This is a narrative review with level of evidence V
Renal transplantation outcomes are better than long term dialysis outcomes…A lot of patients are on waiting list for transplantation because of organ donor shortage….Dual Kidney transplantation is way to accept marginal kidneys and increase nephron mass for donation especially with ECD and DCD…
IT was there 1966, Johnson and his team did the first dual kidney transplant from donor above 60 years with history of HTN,DM and creatinine clearance between 40-80ml/min/m2…
There are no guidelines for dual kidney transplants. All the available evidence are usually center based and experience based…
The most widely used criteria for donors of dual kidney transplant are; Donor age>60 years, Donor’s creatinine clearance between 30-60ml/min/m2, donor terminal creatinine>1.97, donors with diabetes, hypertension non heart beating donors, proteinuria and renal anatomical abnormality…It is customary to do a renal biopsy for donors if there is ECD or kidney with abnormalities….If the donors pre transplant kidney biopsy shows less than 50% GS we can accept…If the remuzzi score is between 7 to 12 we should discard the kidney….
It is important to select the recipient that it should be age matches with the donors, they should be of less immunological risk and minimal co morbidities with low BMI….
.
Surgical techniques: There are bilateral Gibson incision to place both the kidneys but this is a longer procedure and required longer anesthesia….The midline infra umbilical incision is used as it is associated with less dissection and shorter duration…Unilateral placement of both the kidneys are preferred where right kidney is above the left kidney..Right renal arery is anastamosed with right CIA…right renal artery is anastamosed to IVC.. The left renal vessels are anastomosed with the recipients external iliac vessels…
Pediatric En block kidneys are also taken up and there is a higher chance of graft thrombosis….
The rates of DGF in DKT is similar to single kidney transplant with standared criteria donor…The overall patient survival is similar in dual kidney and single kidney transplant …GRaft survvial is similar in Dual kidney transplant and single kidney transplant….
Nazik Mahmoud
2 years ago
Dual kidney transplant is used mainly for marginal kidneys like in ECD ( old age ,low GFR with high serum creatinine so by this method you will increase the nephron mass and the result was comparable with the single kidney transplant
Theepa Mariamutu
2 years ago
Dual kidney transplant may increase the functional nephrons. Kidneys being rejected for a single kidney transplant by other units were accepted for dual kidney transplantation
Donors were considered for DKT if any 2 of the following criteria present:
1. age greater than 60 years
2. creatinine clearance greater than 65 mL/min,
3. rising serum creatinine greater than 2.5 mg/dL at retrieval,
4. chronic hypertension or type 2 diabetes mellitus,
5. glomerulosclerosis on biopsy between 15% and 50%
Donors older than 65 years old with at least 1 of the following risk factors were considered:
HTN,
type 2 DM
atherosclerotic disease
death from a cardiovascular event
Best candidate for DKTs:
suggested to match recipients with donors by age and size, e.g., matching an older donor with an older recipient
To reduce possible injury to limited nephron mass, most authors have suggested DKTs to recipients with lower immunologic risk
Younger candidates can more easily recover from the longer operative time necessary for DKTs
Surgical technique
Haider and associates described midline infraumbilical incision in 2007, with blunt dissection of extraperitoneal space bilaterally to expose iliac vessels. Midline incision has a shorter operative time and dissection and fewer hernia complications
Mason and Hefty in 1998-Unilateral placement of both kidneys The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava.left kidney vascular pedicle anastomosed to external iliac vessels, after de-clamping of the common iliac artery and renal vein, and clamping the external iliac vessels distally
Ekser and associates modified the unilateral extraperitoneal DKTs-The right kidney was placed superiorly, but the renal vein was extended and anastomosed to the external iliac vein instead of the inferior vena cava. The transplant ureters were anastomosed through 2 separate extravesical ureteroneocystostomies on ureteric stents. This technique has shorter operative time and length of hospital stay and a lower delayed graft function rate versus bilateral placement of DKT done by same team
Graft and patient survival
The 2007 review of the UNOS database found that recipients of DKTs from ECDs had similar death-censored graft survival, but during follow up recipients of kidneys from standard criteria donors had better survival of 80%
Spanish report that compared survival of DKT recipients with SKT recipients of SKT found that there were no significant differences in patient or graft survival at 1 year
The 2008 report from the UNOS database, found that incidence of DGF in DKT was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors
En block kidney transplant was associated with slightly increased risk of graft loss when compared to SKTs
Challenges:
technical difficulties, with longer operative time and lower kidney quality
Urinary tract complications are slightly higher, mainly urinary tract fistulas that may need surgery
vascular thrombosis was higher
Ekser and associates found that 2% renal vein thrombosis occurred in both the bilateral and ipsilateral DKT groups
Hobart and associates reported a higher EBK complication rate than SKT mostly due to smaller vessels
In Nutshell:
increased the pool of donation by using marginal kidneys
outcome is comparable to SKTs
Mohammed Sobair
2 years ago
Introduction:
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.” Which kidney is suitable for dual transplant?
In a review of UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%. Three-year graft survival was 79.8%.
United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present:
history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
Kidneys with prolonged warm ischemia time, small kidneys, e GFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus.
Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
Kidneys were used for SKT if pressure flow index was 0.4 mL/min per 100 g/mm Hg and glutathione transferase was less than 100 IU/L/100 grams renal mass.
If pressure flow index was less than 0.4, kidneys were discarded. Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (e.g., comorbidities or cold ischemia). Who is a suitable recipient?
Most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
Most authors have suggested DKTs to recipients with lower immune – logic risk (i.e., recipients without previous transplant and panel reactive antibody titer < 50%)
In general, DKT is offered to patients 60 years or older.
DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2. Surgical technique:
Because most recipients are 55 years or older, reduction of total anesthetic, a shorter operative time, and less vascular anastomoses are desirable.
Unilateral placement of both kidneys:
The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava. Clamps were released, allowing perfusion of transplanted kidney before both the external iliac vein and external iliac artery were clamped distally to allow the anastomosis of left kidney vascular pedicle to external iliac vessels.
A modification was described in Ekser and associates in a report of 29 unilateral extra peritoneal DKTs.
Pediatric kidneys have higher risk of surgical complications, especially vascular as a result of small vessel size. En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk. Graft and patient survival:
Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%. During the same follow-up, recipients of kidneys from standard criteria donors had better survival of 80%. Complications
Local wound dehiscent.
Renal graft thrombosis.
Urinary tract fistulas.
Dalia Ali
2 years ago
Introduction
During the past decades, there have been major improvements in kidney transplant. Better peri operative care and immunosuppressive agents have improved patient outcomes. Renal transplant is the treatment of choice for patients with end-stage renal disease. In the United States, patients waiting for kidney transplant now number 50000 with an annual death rate of 6.3%.1 To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
which kidney is suitable for dual transplant? Dual kidney transplant is a waste of resources if a single kidney will keep the recipient dialysis independent. Equally, having a DKT with insufficient function is extremely unwelcomed. Thus, the decision of which kidney is suitable for dual transplant is crucial. There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers. In addition, the variations in practice and protocols between different surgeons and centers have led to differences in kidney selection criteria.
who is a suitable recipient? Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size. Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested. One reason is that the limited functioning nephron mass would be enough for an elderly recipient with limited metabolic demands and the elderly would not require graft survival of greater than 20 years based on their expected lifespan.
Surgical technique Johnson and associates6 described the first DKT; the original technique included bilateral Gibson incision and transplanting 1 kidney to each side. This method required more tissue dissection and a longer operative time. Because most recipients are 55 years or older, reduction of total anesthetic, a shorter operative time, and less vascular anastomoses are desirable.
Graft and patient survival The earliest report of DKT documented 100% graft and patient survival in 9 DKTs. Although the mean follow-up was short (6 months; range, 2-14 months), recipients of DKT had better graft function than both control groups (recipients of SKT from donors > 60 y or from donors < 50 y).
Complications
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality. Lee and associates14 reported a local wound dehiscence rate of 5% in their series of 41 DKTs. Their approach was midline extraperitoneal bilateral placement of both kidneys. Early renal graft thrombosis is a cause of concern in DKT. In a report, 5 kidneys (12%) of 42 transplanted kidneys showed thrombosis. One patient had bilateral thrombosis, and 3 recipients had single kidney thrombosis but with renal function preserved by the other kidney.
Conclusions
Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys. Ipsilateral placement of both grafts is widely accepted and performed. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs. Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate. The main question is which kidney is more suitable as DKT or SKT. Selection criteria for DKTs are still variable and center dependent. There is reluctance of many centers to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide. More research should help to develop standardized criteria for DKT kidney allocation.
Hinda Hassan
2 years ago
Dual Kidney Transplant
The concept of dual kidney transplant orginated from the fact that single marginal kidney provide suboptimal number of functional nephrons while receiving 2 marginal kidneys would provide more nephrons. Criteria for selection of the kidneys for dual transplant:
There is consensus due to the fact that few centers adopt this and furthermore they use different protocols. criteria used in the early studies were age more than 60 years , long history of hypertension or diabetes with cold ischemia time less than 30 hours, creatinine clearance levels between 80 and 40 mL/min , kidneys that showed less than 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy and rejected kidneys from a single kidney transplant.
Remuzzi scoring system is based on pretransplant biopsy findings and kidneys with a score was between 4 and 6 are used for dual kidney transplant.
UNOS data used kidneys for dual transplant if any 2 of the following are present: age more than 60 years, creatinine clearance more than 65 mL/min, rising serum creatinine more than 2.5 mg/dL at retrieval, chronic HTN or type 2 DM, and glomerulosclerosis on biopsy between 15% and 50%.
sclerosis was > 20% in donated kidneys was associated with higher delayed graft function (80%) . donor eFGR used instead of biopsy-based decisions. the eGFR between 60 mL/min and 30 mL/min were used for DKT. Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. eGFR between 60 mL/min and 30 mL/min.
United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
The auther’s center also uses the last approach. Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus. Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
Newcastle experience used kidney donations for DKT. Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (eg, comorbidities or cold ischemia).
Recipient selection:
matching recipients with donors by age and size.
recipients with lower immuno logic risk
DKT is offered to patients 60 years or older.
The auther criteria are low immunological risk, less than 60 years old, have minimal comorbidities and body mass index < 30 kg/m2. Surgical technique
bilateral Gibson incision and transplanting 1 kidney to each side.
A midline extraperitoneal approach was described to minimize dissection and operative time.
Because the left iliac vein is in a deeper anatomic position, the left kidney with its longer renal vein was placed on the left side. Drains were placed bilaterally.
single midline incision advantages are : a shorter operative time and dissection , fewer hernia complications , a potential wound infection would be far away from the graft, can be converted easily to an intraperitoneal approach,
The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava. Clamps were released, allowing perfusion of transplanted kidney before both the external iliac vein and external iliac artery were clamped distally to allow the anastomosis of left kidney vascular pedicle to external iliac vessels. With this method, both ureters were spatulated and joined to each other. The conjoint ureters were anastomosed to the bladder with ureteric double J stent. This technique reduced trauma from the surgical procedure and operative time. Moreover, the contralateral side remained untouched for possible future transplant.
A modification was right kidney was placed superiorly, but the renal vein was extended using the donor’s inferior vena cava patch. It was anastomosed to the external iliac vein instead of the inferior vena cava. The group also anastomosed the transplant ureters through 2 separate extravesical ureteroneocystostomies on ureteric stents. The upper kidney ureter was placed lateral to the lower kidney ureter. Less dissection as the inferior vena cava is not used for anastomosis is an advantage.
Auther center extend the short right renal vein using the donor inferior vena cava anastomosed to the recipient’s inferior vena cava and use the common iliac artery as an inflow artery . Graft and patient survival
The quality of DKT function is as important as how long it will keep functioning since the aim is to keep the patient dialysis independent for as long as possible. Many factors affect graft function, including donor factors, donation circumstances, cold ischemia time, and perioperative events. Complications
technical difficulties, with longer operative time and lower kidney quality. a local wound dehiscence Early renal graft thrombosis Urinary tract complications especially urinary tract fistulas ureteric stenosis
Postoperatively, recipients of DKT have a higher risk of developing myocardial infarctions ,Higher postoperative admission rates to an intensive care unit
“wandering kidney,” the upper graft wandering to lay posterior to the lower graft.
Ahmed Omran
2 years ago
The practice of DKT into a recipient has been implemented to augment nephron mass in marginal single kidneys, ECD, donors due to cardiac death.
Usually the DKT is thought of if donors age >60years, Cr cLl >65ml/min/m2, serum Cr >2.5mg/dl at the time of retrieval, HTN , DM with end organ damage, or biopsy showing glomerulosclerosis is 15-50%.
The suitable candidates are those having age 60 years or more and minimal immunological risk.
The dual kidney transplant increased the pool of potential organs for donation through increasing use of marginal kidneys.
Rihab Elidrisi
2 years ago
The concept of DKT in a recipient has been adapted to increase nephron mass in marginal single kidneys, ECD, and donors with cardiac death. Usually, the DKT is considered if donors age > 60 years, CrCl >65ml/minutes/m2, s.Cr >2.5mg/dl at the time of retrieval, hypertension, DM with end-organ damage, on biopsy the glomerulosclerosis is 15-50%. The suitable candidates are those with aged 60 years or more and minimal immunological risk. In a sense, the dual kidney transplant has increased the pool of potential organs by increasing the use of marginal kidneys.
Conclusions · DKT increased the pool of donation by using marginal kidneys · DKTs outcome is comparable to SKTs · which kidney is more suitable as DKT or SKT is still questionable
CARLOS TADEU LEONIDIO
2 years ago
Please provide a summary of this article
With the increased use of organs with extended criteria (marginal kidney), there is an increase in organ transplants with a suboptimal number of functioning nephrons, bringing the risk of recipients not becoming independent of hemodialysis. And this risk becomes even greater when we remember that episodes of acute rejection, drug toxicity (particularly of calcineurin inhibitors), and the effect of recipient comorbidities on the transplanted kidney will also adversely affect these limited functional nephrons.
This need to increase the viable “mass of nephrons” gave rise to the idea of performing a transplant of two marginal organs from the same donor – double kidney transplantation, which in animal models has already been shown to effectively prevent the progressive deterioration of kidney function compared to controls of single transplant.
However, not everything is benefits. With the use of Double Transplantation (DKT) there is an increased risk of surgical complications due to the longer surgical procedure and the double risk associated with double vascular and ureteral anastomoses (increased early renal thrombosis, increased urinary tract fistulas requiring surgical repair, dehiscence of surgical wounds, among others), among other events that should be considered:
– which organs are suitable for DKT? So that it is not wasteful for 2 individual transplants, or even an insufficient double;
– which receiver is suitable for DKT ? Older patients would have a lower metabolic need for marginal kidneys and would use less immunosuppressants with a risk of kidney damage;
Despite these points, double kidney transplantation has increased the pool of potential organs by increasing the use of marginal kidneys, with graft and patient survival outcomes, complications, and quality of kidney function provided by double transplants being comparable to single kidney transplants. Therefore, the adoption of DKT by more centers depends only on the adoption of clearer criteria for organ allocation.
rindhabibgmail-com
2 years ago
The concept of DKT into a recipient has been adapted to increase nephron mass in marginal single kidneys, ECD, donors with cardiac death.
Usually the DKT is considered if donors age >60years, CrCl >65ml/minutes/m2, s.Cr >2.5mg/dl at the time of retrieval, hypertension, DM with end organ damage, on biopsy the the glomerulosclerosis is 15-50%.
The suitable candidates are those with age 60 years or more and minimal immunological risk.
In a sense the dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys.
hussam juda
2 years ago
INTRODUCTION
· The transplant of a single marginal kidney may result in a suboptimal number of functional nephrons
· Transplanting 2 marginal kidneys to the same recipient, may increase the functional nephrons
· Kidneys being rejected for a single kidney transplant by other units were accepted for dual kidney transplantation
· Donors were considered for DKT if any 2 of the following criteria present:
1. age greater than 60 years
2. creatinine clearance greater than 65 mL/min,
3. rising serum creatinine greater than 2.5 mg/dL at retrieval,
4. chronic hypertension or type 2 diabetes mellitus,
5. glomerulosclerosis on biopsy between 15% and 50%
· Donors older than 65 years old with at least 1 of the following risk factors were considered: HTN, type 2 DM, atherosclerotic disease, or death from a cardiovascular event
· To select the best candidate for DKTs, it was suggested to match recipients with donors by age and size, e.g., matching an older donor with an older recipient
· To reduce possible injury to limited nephron mass, most authors have suggested DKTs to recipients with lower immunologic risk
· Younger candidates can more easily recover from the longer operative time necessary for DKTs
Surgical technique
· The first DKT was described by Johnson and associates; the original technique included bilateral Gibson incision and transplanting 1 kidney to each side. This procedure needs more tissue dissection and a longer operative time
· Haider and associates described midline infraumbilical incision in 2007, with blunt dissection of extraperitoneal space bilaterally to expose iliac vessels. Midline incision has a shorter operative time and dissection and fewer hernia complications
· Unilateral placement of both kidneys was described by Mason and Hefty in 1998.
– The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava
– left kidney vascular pedicle anastomosed to external iliac vessels, after de-clamping of the common iliac artery and renal vein, and clamping the external iliac vessels distally
· Ekser and associates modified the unilateral extraperitoneal DKTs:
1. The right kidney was placed superiorly, but the renal vein was extended and anastomosed to the external iliac vein instead of the inferior vena cava
2. the transplant ureters were anastomosed through 2 separate extravesical ureteroneocystostomies on ureteric stents
3. This technique has shorter operative time and length of hospital stay and a lower delayed graft function rate versus bilateral placement of DKT done by same team
· En block kidney transplant using pediatric donor aorta and the inferior vena cava used to reduce vascular complications of pediatric kidneys.
Graft and patient survival
· The earliest report of DKT documented 100% graft and patient survival in 9 DKTs
· Lee and associates suggested an older donor for older recipient strategy
· The 2007 review of the UNOS database found that recipients of DKTs from ECDs had similar death-censored graft survival, but during follow up recipients of kidneys from standard criteria donors had better survival of 80%
· Spanish report that compared survival of DKT recipients with SKT recipients of SKT found that there were no significant differences in patient or graft survival at 1 year
· Pediatric kidneys transplanted into adults as EBK have shown encouraging results
· The 2008 report from the UNOS database, found that incidence of DGF in DKT was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors
· En block kidney transplant was associated with slightly increased risk of graft loss when compared to SKTs
Complications
· with DKT are higher due to technical difficulties, with longer operative time and lower kidney quality
· Urinary tract complications are slightly higher, mainly urinary tract fistulas that may need surgery
· vascular thrombosis in the DKT group was higher
· Ekser and associates found that 2% renal vein thrombosis occured in both the bilateral and ipsilateral DKT groups
· Hobart and associates reported a higher EBK complication rate than SKT mostly due to smaller vessels
Conclusions
· DKT increased the pool of donation by using marginal kidneys
· DKTs outcome is comparable to SKTs
· which kidney is more suitable as DKT or SKT is still questionable
AMAL Anan
2 years ago
It is considering if SKT make patient dialysis I dependent
by increasing the pool of potential organs by increasing use of marginal
kidneys.
According to clinical practice guidelines
Pretransplant Biopsy Protocol
Glomerular Global Sclerosis: Based on 3 sections (First, Middle and Last if
available), the number of globally sclerosed glomeruli expressed as
percentage
0 None globally sclerosed
1 < 20% global glomerulosclerosis
2 20% – 50% global glomerulosclerosis
3 > 50% global glomerulosclerosis
Tubular Atrophy
0 Absent
1 < 20% tubuli affected
2 20% – 50% tubuli affected
3 > 50% tubuli affected
Interstitial Fibrosis
0 Absent
1 < 20% of renal tissue replaced by fibrous connective tissue
2 20% – 50% renal tissue replaced by fibrous connective tissue
3 > 50% of renal tissue replaced by fibrous connective tissue
Arterial and arteriolar narrowing: For the vascular lesions, if the changes are
focal, the most severe lesion present gives the final grade
0 Absent
1 Increased wall thickness but to a degree that is less than the
diameter of the lumen
2 Wall thickness that is equal or slightly greater to the diameter of the
lumen
3 Wall thickness that far exceeds the diameter of the lumen with
extreme luminal narrowing or occlusion
Only biopsies with ≥ 25 glomerules considered for evaluation. Kidneys with
evidence of acute tubular necrosis are not considered for DKT
Esraa Mohammed
2 years ago
Introduction
*Renal transplant is the treatment of choice for patients with end-stage renal disease.
*The transplant of a single marginal kidney (from
ECDs, donors with cardiac death, and pediatric
donors) may result in a suboptimal number of
functional nephrons to allow recipients to become
dialysis independent.
*The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.
which kidney is suitable for dual transplant?
Donors were considered for DKT if any
2 of the following criteria present:
-age greater than 60 years
-creatinine clearance greater than 65 mL/min,
-rising serum creatinine greater than 2.5 mg/dL at
retrieval
– chronic hypertension or type 2 diabetesmellitus,
– glomerulosclerosis on biopsy between 15% and 50%
who is a suitable recipient?
-patients 60 years or older.
-low immunological risk
– who are less than 60 years old, and who have minimal comorbidities
-body mass index < 30 kg/m2.
Graft and patient survival
Many factors affect graft function, including
donor factors, donation circumstances, cold ischemia
time, and perioperative events.
In the initial reports of DKT, delayed graft function was 11%. In the same study, delayed graft function reached 50% in SKT from older donors (> 60 y) and 20% in SKT from
younger donors (< 50 y).
Complications
*Complications with DKT are perceived to be higher
due to technical difficulties, with longer operative
time and lower kidney quality.
*Urinary tract complications
*vascular thrombosis
Conclusions
-Dual kidney transplant has increased the pool of
potential organs by increasing use of marginal kidneys.
-Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
-Selection criteria for DKTs are still variable and center dependent.
Hamdy Hegazy
2 years ago
Please provide a summary of this article
Limitations
Evidence level
This a narrative review study with level V evidence. Renal transplantation outcomes are better than long term dialysis outcomes. A lot of patients are on the waiting list for transplantation because of shortage of donors. Dual kidney transplantation (DKT) is a way to accept marginal kidneys and increase nephron mass for donation especially with ECD after DCD. In 1996, Johson and his team did the first adult DKT when they transplanted kidneys from donors above 60-year-old with history of HTN, DM and Creatinine clearance between 40-80 ml/min/m2, CIT below 30 hours with GS less than 40% without severe IF or arteriosclerosis. 6 months patient and graft survival were 100%.
There are no available guidelines for allocation of DKT, it is usually center based.
Most widely used criteria for Donors of DKT: 1- Donor’s age>60 2- Donor’s Creatinine clearance between 30-60 ml/min/m2. 3- Donor’s terminal creatinine> 1.97 mg/dl. 4- Donor’s medical background: DM, HTN, non-heart beating donors, proteinuria below 3 gm/day or renal anatomical abnormalities. 5- Donor’s pre-transplant kidney biopsy: GS<50%, discard kidneys with Remuzzi score 7-12. Most widely used criteria for Recipients of DKT: 1- Age matched recipient with the donor. 2- Low immunological risk. 3- Minimal co-morbidities, low BMI. Surgical Techniques: 1- Bilateral Gibson incision (longer procedure and longer anesthesia). 2- Mid-line infra-umbilical incision (less dissection, shorter duration, less incidence of hernia). 3- preferred one is unilateral placement of both kidneys where right kidney is above left kidney and the right renal artery is anastomosed with the recipient CIA, right renal vein is anastomosed with the IVC. The left renal vessels are anastomosed with the recipient external iliac vessels. 4- In pediatric donors, the technique is En-block DKT which carries a higher risk of vascular complications up to graft thrombosis. The age of pediatric donors is usually between 2-5 years. Outcomes of DKT: 1- Rate of DGF in DKT is similar to SKT with SCD. 2- Rate of DGF in DKT is lower than SKT with ECD. 3- Patients survival is similar in DKT to SKT. 4- Graft survival is similar in DKT to SKT. 5- DKT with ECD has similar death censored graft survival. 6- En-block DKT has better graft survival at 1,3 and 5 years with similar rates of DGF. 7- DKT carries higher risk of surgical complications compared to SKT. 8- Longer stay in ITU.
Limitations of the study: 1- Retrospective data. 2- The donors were not matched. 3- No trial to compare DKT vs SKT.
Manal Malik
2 years ago
Summary of Dual Kidney TransplantUse the kidney from extended criteria a donors increase donor pool and organ shortage especially for whom on long time wating list .
Dual renal transplant into recipient aim to increase the nephron mass.
DKT has ahigh risk of surgical complication included vascular and ureteric anastomoses.
Many centres lack experience with DKT .
Absence of guidelines and allocation policies. Selection criteria for DKT
First DKT recipient Jonson used kidney from donors more than 60 years old or long history of HTN or DM with cold ischemia less than 30 hours or creatinine clearance between 40 to 60 ml/min and less than 40% glommularscleosis without interatrial fibrosis or arteriosclerosis on biopsy.
Remuzzi used scoring system based on pretransplant biopsy for selection of a kidney for DKT .
Brain death donor more than 60 years old who were DM or donor with presence of proteinuria of less than 3 gm/24hours were considered.
Both kidney were biopsied and less 25 glommuleri were excluded.
4- 6 score so DKT can be carry on ,
Limitation of kidney biopsy :
Can be taken from kidney surface and be misleading which will overestimate glommuloscleosis.
Risk od bleeding and AVF as complication of kidney biopsy .
Using eGFR as criteria to select donor(sues Cockcroft and Gault):
eGFR more than 60 ml/min for SKT.
eGFR less than 30 ml/min kidney were discarded .
eGFR in between for DKT.
Using hypothermic machine perfusion to decided kidney donors:
Depend on pressure flow index which is enzyme marker of ischemic injury .
Pressure of flow index was 0.4ml/min per 100gmmHg and glutathione transferee less than 100iu /L 100gm renal mass.
If less than 0.4 kidney were discarded.
DKT if :
Pressure flow index was satisfactory but GST was higher than cut off value for SKT or other risk factor such as cold ischemia or other comorbidities. Suitable recipient for DKT
Recipient with low immunological risk or PRA less than 50%.
Recipient age less than 60 years old.
Recipient with BMI less than 30 gm kg/ml.
Larger study showed no difference in complication rates between ipsilateral DKT and SKT . Conclusion
· DKT increased the pool of potential organs.
· Ipsilateral placement of both graft is accepted and performed.
· Result of graft and patient survival complication and quality of renal function by DKT are comparable to SKTs .
· Selection criteria for DKT is centre dependent.
· Many centre still not performing DKT as no clear guidelines and this decision transplant dependence.
Huda Saadeddin
2 years ago
During the past decades, dual kidney transplant has enabled greater use of marginal kidneys and reduced waiting time.
Kidney survival and function are encouraging and close to results with standard criteria single kidney transplant.
To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available versus with a single suboptimal organ or as many functioning nephrons versus with a single ideal kidney
Nephron mass as a determinant of chronic allograft failure has been experimentally tested in animals, with results showing that increasing the size of viable nephron mass by transplanting 2 kidneys to the same recipient effectively prevents progressive deterioration in renal function compared with single transplant controls.
In a review of UNOS practices by Gill and associates, between 2000 and 2005, DKTs from donors > 50 years old accounted for only 4% of transplants.
Moreover, 54% of the kidneys from donors > 65 years old in the United States and 12% in Europe are discarded.
These limitations clearly indicate the need to expand DKT practice.
which kidney is suitable for dual transplant?
There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers.
Johnson and associates 6 used kidneys from donors
older than 60 years
long history of hypertension or diabetes
cold ischemia time less than 30 hours.
creatinine clearance levels between 80 and 40 mL/min and
with kidneys that showed less than 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy.
Kidneys being rejected for a single kidney transplant (SKT) by other units were criteria.
Remuzzi and associates suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT. > Brain dead donors older than 60 years- >donors who were diabetic, or >donors with presence of proteinuria of less than three grams/24 hours were considered. >Kidneys with macroscopic major vascular abnormality or evidence of focal scarring (ie, chronic pyelonephritis) were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. Dual kidney transplants were performed if a priori score was between 4 and 6
Spanish group, kidneys from brain dead donors.
normal serum creatinine levels were considered for DKT if donors older than 75 years old.
In addition, donors between 60 and 74 years old with glomerulosclerosis of 15% to 50% at biopsy also were included.
Both kidneys were biopsied, and the higher glomerulosclerosis percentage was considered. Kidneys with less than 15% glomerulosclerosis were transplanted separately, and kidneys with greater than 50% glomerulosclerosis were discarded.
UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present:
age greater than 60 years,
creatinine clearance greater than 65 mL/min,
rising serum creatinine greater than 2.5 mg/dL at retrieval,
chronic hypertension or type 2 diabetes mellitus,
and glomerulosclerosis on biopsy between 15% and 50%.
who is a suitable recipient?
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size. Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
To reduce possible injury to limited nephron mass, most authors have suggested DKTs to recipients with lower immunologic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%).
In general, DKT is offered to patients 60 years or older. Our group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2 .
>>>>>>>> The quality of DKT function is as important as how long it will keep functioning since the aim is to keep the patient dialysis independent for as long as possible. Many factors affect graft function, including donor factors, donation circumstances, cold ischemia time, and perioperative events. In the initial reports of DKT, delayed graft function was 11%. In the same study, delayed graft function reached 50% in SKT from older donors (> 60 y) and 20% in SKT from younger donors (< 50 y).
Complications Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality.
Early renal graft thrombosis is a cause of concern in DKT.
Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery
Conclusions
Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys. Ipsilateral placement of both grafts is widely accepted and performed. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate.
The main question is which kidney is more suitable as DKT or SKT. Selection criteria for DKTs are still variable and center dependent.
There is reluctance of many centers to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide.
More research should help to develop standardized criteria for DKT kidney allocation.
Marius Badal
2 years ago
Summary of the article.
Introduction:
Over the years the use of immunosuppressive and peri-operative care has improved the outcome of a kidney transplant. However, there was still the need to improve the post-transplant outcome of the kidney. This is why the introduction of dual kidney transplantation was introduced. The reason is that kidney transplantation is still the best option for kidney failure. In other to continue to improve kidney outcomes more research is being conducted with a combination of the currently well-known ones to continue improving the renal outcomes. This is why the introduction of dual transplantation.
It was first introduced in the United States around 1996 by Johnson and associates. The transplantation of a single kidney from ECD, DCD, AND DBD may give a suboptimal renal function due to a reduction of renal mass and nephrons. So the introduction of dual renal transplantation was adopted and as such give the possibility increase renal mass and possibly better renal function and outcome. So the idea came when 2 kidneys can be given when they have marginal functions and as such will have better kidney function rather than giving only one suboptimal kidney.
So with such a trial transplanting 2 kidneys, to the same recipient may prevent the progression of kidney failure and improve renal function when it is compared to a single transplant. It must be noted that dual kidney transplantation may carry higher risks like surgical complications due to a longer procedure, and the possibility of thrombosis.
Who has the criteria for dual kidneys?
1) Donors that are older than 60 years old
2) Duration of baseline pathologies like HTN and DM and also the presence of cold ischemia
3) The creatinine clearance is about 40-80 ml/min
4) On biopsy may show arteriosclerosis, or a less than 40 % GS
5) The Remuzzi criteria about 4-6
The recipient may be someone who is older than 60 years old, has lower immunological risk, and has a BMI of less than 30 kg/m2 and minimal comorbidities.
There have been special surgical techniques that have been described like the midline extraperitoneal approach and the unilateral placement of both kidneys.
Conclusion:
The outcome of the graft survival and the patient outcome and complication is comparable to single kidney transplantation. However, it must be noted that there are complications to the procedure like renal graft thrombosis, and urinary fistula.
Dual kidney transplantation has improved the donor pool by increasing marginal kidneys.
The use of the pediatric block technique in adult recipients has been in an encouraging outcome.
The concept and use of dual kidneys have not been accepted in some centers due to a possible lack of knowledge and guidelines and as such more studies need to done and the creation of guidelines.
Dr. Tufayel Chowdhury
2 years ago
Introduction: The transplant of a single marginal kidney (from ECDs, donors with cardiac death, and pediatric donors) may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent.
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available nephron mass. The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available.
Which kidney is suitable for dual transplant?
There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers.
In 1999, Remuzzi and associates 4 suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT. Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered. Kidneys with macroscopic major vascular abnormality or evidence of focal scarring (ie, chronic pyelonephritis) were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. Dual kidney transplants were performed if a priori score was between 4 and 6.
In a 2000 study by a Spanish group, kidneys from brain dead donors with normal serum creatinine levels were considered for DKT if donors older than 75 years old. In addition, donors between 60 and 74 years old with glomerulosclerosis of 15% to50% at biopsy also were included.
In a review of UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%.
To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead. Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
who is a suitable recipient?
Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
Surgical technique:
The single midline incision has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision. A modification was described in Ekser and associates in a report of 29 unilateral extraperitoneal DKT. The right kidney was placed superiorly, but the renal vein was extended using the donor’s inferior vena cava patch. It was anastomosed to the external iliac vein instead of the inferior vena cava. The group also anastomosed the transplant ureters through 2 separate extravesical ureteroneocystostomies on ureteric stents. The upper kidney ureter was placed lateral to the lower kidney ureter. Less dissection as the inferior vena cava is not used for anastomosis is an advantage.
Conclusion:
Kidney survival and function are encouraging and close to results with standard criteria single kidney transplant.
Shereen Yousef
2 years ago
This literature review of different DKT aspects, techniques, and results that address points for further research.
dual kidney transplant has enabled greater use of marginal kidneys and reduced waiting time.
transplant of a single marginal kidney result in a suboptimal number of functional nephrons which will be fragile and easily affected by episodes of acute rejection, medication toxicity, and effect of the recipient’s comorbidities.
concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
Although no randomized prospective studies to compar results of DKT with single transplant, but some studies have reported acceptable results even with kidneys considered unacceptable by others.
It still uncommon in many centres due to lack of solid guidelines and relatively higher surgical complications.
▪︎which kidney is suitable for dual transplant?
the decision of which kidney is suitable for dual transplant is crucial.
There is no global consensus about it,
the variations in practice and protocols between different surgeons and centers have led to differences in kidney selection criteria.
a review of UNOS published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005.
Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%.
Three-year graft survival was 79.8%.
Pretransplant biopsy is important to evaluate donor kidneys as it was shown that Five-year survival was 80% when protocol biopsy showed no glomerulosclerosis and dropped to 35% when sclerosis was > 20% in donated kidneys,with higher incidence of DGF ( 80%) with sclerosis > 20%.
Biopsy may sometimes be misleading to avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead ,donors with eGFR 30-60 mL/min were considered for DKT.
▪︎who is a suitable recipient?
there is debate about the best candidate for DKTs.
matching an older donor with an older recipient is suggested.
To reduce possible injury to limited nephron mass, it was suggested DKTs to recipients with lower immuno-logic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%). The study group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2 .
▪︎Graft and patient survival
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs. Although the mean follow-up was short (6 months; range, 2-14 months).
studies on older donor for older recipient strategy reported similar patient and graft survival at 1 year.
Few Studies that compared patient and graft survival for SKT and DKT found no difference.
reports on pediatric kidneys transplanted into adults as EBK have also shown encouraging results.
2003 reported results of 2160 recipients of EBK. The report showed that 77% of EBKs were from donors < 5 years old; however, graft survival at 1, 3, and 5 years was superior (85%, 76%, 71%) versus SKT (81%, 68%, 63%).
Two large analyses of the UNOS database have been published. The 2008 report documented 625 DKTs , despite a longer cold ischemia time in the DKT group versus that shown for groups who underwent SKT with ECD and standard criteria donor kidneys but delayed graft function incidence was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors.
▪︎complications
Complications of DKT are higher than SKT due to technical difficulties, with longer operative time and lower kidney quality.
-graft thrombosis and vascular thrombosis were reported in many cases of DKT.
-Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery.
– higher incidence of post operative MI and admission to icu . ▪︎Limitations of the study
-data is retrospective no control group .
– no match in donors age ,medical conditions, cause of death
-Small number of patients and short follow-up period in many of reported studies.
▪︎Conclusions
Dual kidney transplant increased the pool of potential organs by increasing use of marginal kidneys.
Ipsilateral placement of both grafts is widely accepted and performed.
Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
use of pediatric kidneys by an en block technique into adult recipients has resulted good resullts.
Selection criteria for DKTs are still variable and center dependent.
More research should help to develop standardized criteria for DKT kidney allocation.
KAMAL YOUSIF ELGORASHI ADAM
2 years ago
This review is done by our prof; Ahmed Halawa Summary of the article; Introduction; Kidney transplantation is the best treatment modality for ESKD, with improving transplantation, and increasing N0. of waiting list dialysis patient who is fit for transplantation, lead to an increase the need for kidneys to face this need, However, the use of marginal kidneys, ECD, DCD, donors, may help to meet this demand. And with the improvement of preparation o donated kidneys and measures used to keep kidneys of good quality, and gain successful graft function. In considering such kidneys with low nephron mass, the dual kidney transplant practice had been improved and established, so the number of discarded kidneys had become less. And this also can help the usage of the pediatric kidney in adult recipients to achieve a compatible nephron mass. The 1st DKT was done in Us in 1996 by Johnson and associates. DKT carries a potential risk of surgical complication, so it takes more time and hence requires a fit recipient. UNOS practices by Gill and associates in the US between 2000 and 2005, only 4% of transplants were DKT. Donor considered for KDT if any 2 of the following;
Age older than 60 years.
CrCL greater than 65 ml/min.
Rising SCr > 2.5 mg/dl at retrieval.
Chronic HTN.
T2 DM.
GS between 15-50%.
Three years of graft survival was 79.8%. Moreover, 54% of kidneys from donors> 65 years old in the US and 12 % in Europe are discarded, and actually, these limitations rose the need of using a DKT. Kidney’s criteria for DKT:
No global consensus on which donor’s kidney is suitable for DKT.
Different centers and surgeon practices led to different criteria for selection.
Johnsons and associates used kidneys from donors older than 60 years and/or long Hx of HTN, or DM, with CIT less than 30 Hrs.
Kidneys with CrCL between 80 -40 ml/min.
Kidneys that showed GS less than 40%, without severe IF or AS on biopsy.
Rumuzzi and associates DKT criteria based on a pre-transplant biopsy;
DBD, older than 60 years.
Diabetic donor.
Donor with proteinuria less than 3 grams/24 Hr.
Kidneys score between 4 and 6.
All 24 kidneys reported in this study had graft survival of 100%, at 6 months.
Exclude kidneys with macroscopic major vascular abnormality, focal scoring, and those with less than 25 glomeruli in the biopsy.
Spanish group in a 2000 study; Kidneys from BDD with normal S.Cr are considered for DKT if;
Donors older than 75 years.
Donors between 60-74 years, with GS of 15% to 50%, at biopsy.
Kidneys with GS <15% were considered for a single kidney transplant.
Kidneys with GS> 50% were discarded.
Mean donor age was 75+/-7 years.
Graft survival at 6 months was 95% in 21 recipients.
Italian Study between 2003-2009;
involve 100 unilateral DKTs.
Study based on donors age, and histopathological finding.
Mean age was 72+/-5 years old.
Three years graft survival reached 90.9%.
Sever histopathological finding was associated with impaired allograft function, which indicate using biopsy to determine suitability for using marginal kidneys .
5 years survival rate was 80%, with no GS, dropped to 35%, when GS was >20%.
Higher DGF (80%), when GS > 20%.
eGFR donor > 60 ml/min considered for SKD.
Kidney discarded when eGFR < 30 ml/min. Center of the publisher of this study use the following for DKTs;
Kidneys with prolonged WIT.
Small kidneys.
eGFR < 60 ml/min.
Kidneys from donors > 70 years old.
Specially if donor associated with one of the following; HTN, T2DM.
DKTs; from donors with maastricht category 2,(15) donors, and category 3 (8) donors;
All kidneys had hypothermic MP.
Kidneys considered for DKTs if pressure flow index was satisfactory, but GST was higher than cutoff value for SKT, or if other risk factor were present; (comorbidities, CIT).
Mean donor age was 49+/-11 years.
DGF rate of 81%, but 3 month GFR of 46.2+/-13.7 ml/min.
EBK;
Habort and associates, suggest using en bloc KT, when donor age less than 2 years.
33 EBKs, with a 3 years survival rate reaching 87.3%.
In UNOS study of EBK was recommended when BDD were less than 5 years old, reported graft survival was 85% at 1 year, 76% at 3 years, and 71% at 5 years.
Suitable recipients suggestions;
Matched recipients and donor by age and size.
Matched older with older, (limited nephron mass of donor matched with limited metabolic demand of recipient and his/her life expectancy)
Limited acute rejection episodes of elderly recipient as a result of antiproliferative agent with lower dose of nephrotoxic CNIs, would reduce long-term nephron insults.
DKTs to recipients with lower immunogenicity.
Younger recipients with lower immunogenicity, had a benefit over older recipients in that they can tolerate long operation time and can recover faster from anesthesia with lower complication rate.
This article center preferred; recipients with low immunogenicity, who are less than 60 years old, with minimal comorbidities, and BMI <30 kg/m2.
Surgical technique;
Johnson and associates; bilateral Gibson incision, and transplanting each kidney to each side, required longer time and more tissue dissection.
A midline extracorporeal approach, to minimize dissection and operative time.
Left kidney with its renal veins placed on the left side, (left kidney located deeper, with the longer renal vein).
drains placed bilaterally.
Haider and associates; surgical technique in 2007; a single midline incision have advantages of Gibson bilateral incision, with a shorter operation time, less hernia complication, in addition regarding the side of incision the graft will be a way from the wound and its possible infection, but with a higher ileus and bowel complication, mobile graft, and more difficult to biopsy.
Mason and Hefty technique in 1998; the right kidney located up, with renal artery connected to the common iliac artery, and the renal vein to the IVC, remove the clamp and allow perfusion of the 1st kidney. the other kidney anastomosed below with the renal vessels connected to the external iliac vessels. With both ureter conjoined together and anastomosed with the bladder, the other side left free for possible future Tx.
Unilateral DKTs;
Shorter operation time compared with the bilateral DKTs.
95% placed in the right side.
Outcome and surgical complication the same as SKTs.
This article center technique; Use unilateral DKTs, renal vessels anastomosed to the IVC, (exten the short right renal vein with the donor IVC), and common renal artery.
Pediatric kidney transplant;
Higher risk of complication, due to small vessels.
En bloc technique, used a donor aorta, and IVC reduce the risk of small vessels.
Unilateral modified Gibson incision, the donor IVC was anastomose to the recipient EIV, while distal aorta was anastomosed to the EIA, interrupted knot anastomoses to allow the graft grow, and to avoid anastomotic stenosis conjoined ureter anastomosed to the bladder.
In 2003, report of 15 patient show 1- year graft survival was 93%, and 100% patient survival, no vascular complication reported.
Graft and patient survival ;
Recipients with DKT, had better graft function than both SKT from donors >60 years, and < 50 years.
Similar patients and graft survival at 1-year(98% and 89% in DKT vs 97% and 90% in SKT), and 2-years, (86% and 77% in DKT vs 95% and 86% in SKT).
There was significant age difference (59+/-12Y,) and SKT donors (42 +/-17y).
2007 UNOS report, Recipients of DKTs from ECDs had a similar death-censored graft survival, which reached 70%, while kidneys from SCD had better survival 80%.
A French team with older donor reports DKTs (age 75+/-5.8y) graft survival at 3 years, reached about 50%.
Ireland report by D Arcy and associates; superior 3-month patient(92% vs 100%), and graft survival, (88% vs 93%), in recipients of SKT vs DKT.
Mahmud Islam
2 years ago
With improved outcomes of kidney transplants in the face of increased need, the usage of organs from age extremes was suggested. The problem with pediatric donors is the low number of nephrons. The same is applicable for advanced age due to glomerular sclerosis. The renal biopsy (used to be wedge biopsy) exaggerates the number of sclerosed glomeruli because the sample includes a sample from the periphery (renal capsule) where sclerosis begins. this lead /may lead to the avoidance of kidneys unnecessarily. In 2003 UNOS implemented the use of kidneys from extended criteria donors. ECD included donors>60 years and those >50 with a history of HT, CVA or scr>1.97 mg/dl.
Dual kidney transplantation aims to increase the number of functional nephron mass. The first DKT into adults was performed in 1996, preceded 2 decades earlier by transplanting pediatric kidneys into adults. The lengths of operation of DKT discouraged many surgeons because of either lack of experience, lack of consensus guidelines and high probability of surgical complications either because of long duration or vascular complications.
Many trials and groups performed successful operations with encouraging results but the survival of kidneys was higher in the short term than the long term (2- 3 years or more).
To avoid misleading biopsy-based decisions, the eGFR in donor was used for estimation. maximal eGFR > 60 was considered for single kidney transplantation, while eGFR <30 was a reason for avoidance. eGFR between 30-60 was considered for DKT.
Donor selection is an issue, but most centres agree that matching donors’ age is better. Old for old.
Many surgical techniques were performed. First, it was done by bilateral Gibson incision and transplanting each kidney in opposite sides. Later in 2007, Haider and associates used midline incision with the advantage of shorter operation time. In 1998 Mason & Hefty introduced unilateral placement of both kidneys in 1998. The right kidney was placed superiorly with renal a. anastomosed into the common iliac artery and renal v into IVK. EKSER and associates modified this operation by anastomosing the right kidney vein into the external iliac vein instead of IVK using the donor’s IVC patch.
Monolateral placement of kidneys has the advantage of shorter operation time and stay at the hospital.
Hussein Bagha baghahussein@yahoo.com
2 years ago
Introduction
Kidney transplantation is the treatment of choice for ESKD as it offers a mortality benefit over dialysis. However, the number of patients on the waiting list is increasing and the number of organs available for transplantation has reduced. To increase the number of transplants organs from DCDs donors are ECD are being utilized as well as pediatric donors. Transplantation of organs from marginal donors poses a challenge due to the lower number of functioning nephrons and increased risk of DGF and reduced graft survival. Dual kidney transplantation has been utilized to increase the nephron mass and prolong graft survival. This has been tested in animal studies that showed that by increasing the viable nephron mass by transplanting 2 kidneys to the recipient prolongs graft survival. The first adult DKT was performed in 1996 by Johnson and associates. DKT carries a higher risk of surgical complications due to the longer surgical procedure and dual ureteric and vascular anastomoses.
There are no criteria and guidelines as to which donor kidneys can undergo SKT and which ones undergo DKT. There are also no guidelines as to which surgical technique is the best for DKT. Therefore, not very many centers perform DKTs.
Which Kidney Is Suitable For DKT?
The transplant team will have to decide which kidneys can be used for SKT or DKT. If kidneys suitable for SKT are both transplanted in one recipient, it will be a waste of resources and one potential recipient will be on the waiting list for longer. If kidneys that are marginal and have a lower nephron mass undergo SKT, then they will have reduced graft survival.
In the first adult DKT the criteria used was donors older than 60 years, h/o DM and/or HTN and a long cold ischemia time of more than 30 hours. The terminal donor creatinine was between 40-80 mls/min/m2 and the kidneys had less than 40% glomerulosclerosis.
They reported 100% patient and graft survival at six months.
Remuzzi and associates have suggested a scoring system based on pre-transplant biopsy for selection of kidneys for DKT. Kidneys with macroscopic vascular abnormalities, focal scarring or where the biopsy core had less than 25 glomeruli were excluded. DKT was performed if the priori score was between 4 and 6 and they reported a 100% patient and graft survival at six months
In a Spanish study of DKT, they included kidneys form DBD donors who had a normal serum creatinine and were more than 75 years of age or between 60 and 74 years with glomerulosclerosis of between 15% and 50%. Graft survival was 95% in 21 recipients.
Histologic findings determine the rate of graft survival. Five year graft survival was 80% when protocol biopsy showed no glomerulosclerosis and reduced to 35% when glomerulosclerosis was more than 20%. However, on e of the major limitations of using histological criteria is that the biopsies are dependent on the person doing the biopsies. Most surgeon obtain elliptical biopsies from the surface of the kidney and that will give a falsely higher rate of glomerulosclerosis and will lead to DKT or discarding of kidneys.
The terminal donor creatinine and eGFR can be used to avoid biopsy based decisions. eGFR of more than 60 mls/min is considered for SKT and eGFR between 30 and 60 mls/min for DKT. Kidneys with eGFR of less than 30 mls/min were discarded. Snanoudj et al used this protocol and performed 81 DKTs with a 2 year graft survival 90%.
The UK kidney advisory group has suggested that kidneys from donors aged more than 70 years or older can be used for DKT if one or more of the clinical risk factors were present:
History of HTN, MI, DM
CVA as cause of death
Serum creatinine of > 1.97 mg/dL at retrieval
Presence of any anatomic anomaly
Newcastle criteria can also be used to determine if the kidneys should undergo DKT or SKT depending on the HMP characteristics including pressure flow index and perfusate glutathione transferase. If the pressure flow index was 0.4 and the GT was more than 100, then both kidneys would be transplanted in one recipient. If the perfusion pressure was less than 0.4, the kidneys would be discarded.
Who Is A Suitable Recipient?
Many authors suggest matching recipients by donor age and size. An older recipient is normally selected for DKT due to the reduced immune response they generate and limited metabolic demands of elderly recipients. Most authors have also suggested DKTs for recipients with lower immunological risks
Utilizing younger recipients for DKTs has an advantage due to longer operative time for DKTs which can result in prolonged recovery time in the elderly. In general DKT is offered to patients 60 years or older. At the authors center, the recipients given DKTs are younger than 60 years of age, have minimal comorbids and have a BMI less than 30.
Surgical Techniques
The first adult DKT was performed using bilateral Gibson incision and transplanting one kidney on each side. This method required more tissue dissection and a longer operative time. A midline extraperitoneal approach was described to minimize dissection and operative time. It has the advantage of a shorter operative time and dissection and fewer hernia complications compared to a bilateral Gibson incision.
Unilateral placement of both kidneys was described by Mason and Hefty in 1998. The right kidney was placed superiorly with the renal artery anastomosed into the common iliac artery and renal vein into the IVC. With this method, both ureters were spatulated and joined to each other. The conjoined ureters were anastomosed to the bladder with a ureteric double J stent
A modification was described by Esker and colleagues. The right kidney was placed superiorly, but the renal vein was extended using the donor’s IVC patch. It was anastomosed to the external iliac vein instead of the IVC. The group also anastomosed the transplant ureters through 2 separate extravesical ureteroneocytostomies. The upper kidney ureter was placed lateral to the lower kidney ureter.. This technique has shorter operative time and length of hospital stay and a lower DGF
Pediatric kidneys have a higher risk of surgical complications especially vascular due to the small vessel size. En bloc kidney transplant using donor aorta and IVC can theoretically reduce that risk. One of the main concerns of transplanting the kidneys en bloc is the risk of torsion of the whole bloc or one kidney at risk of thrombosis due to a longer vascular pedicle Graft and Patient Survival
Earlier reports showed that the patient and graft survival was 100% although the mean follow up was for only six months
Using an older donor to older recipient strategy, Lee et al reported similar graft and patient survival outcomes compared to SKTs. However, the 2007 review of the UNOS database showed that the SKTs had better survival than DKTs
DKTs had lower rates of DGF when compared to SKTs from ECDs and similar rates when SKTs from SCDs
The PNF was also low at 1.8% Complications
Complications are perceived to be higher with DKTs due to the technical challenges and the longer operative times with low quality kidneys. Midline extraperitoneal approach is associated with a dehiscence rate of 5%. Early renal graft thrombosis is also a concern in DKTs.
urinary tract complications have also been reported to be slightly higher especially urinary tract fistulas requiring surgery. In a French report, 11% of the recipients had ureteric stenosis and a similar rate urinary fistula.
Postoperatively, recipients of DKTs have a higher risk of developing MIs compared to SKT candidates.
Monolateral placement of both kidneys reduces the length of the surgical procedure and the length of the hospital stay. A large study showed no differences in complication rates between ipsilateral DKT and SKTs
En bloc kidney transplantation has a higher risk of complications compared to SKT. Thrombosis of the renal vein, artery or even the donors aorta was observed in the series reported by Hobart et al
One can also get a wandering kidney where one of the kidneys can move from its location. Conclusion
DKT has increased the donor pool and has the potential of reducing waiting times. If carefully selected, DKTs have similar graft and patient survival as compared to SKTs. DKTs reduce the rates of DGF and PNF.
The surgical complications of DKT can be reduced by ipsilateral placement of the kidneys as this reduces surgical time and the length of hospital stay
Abdulrahman Ishag
2 years ago
Dual Kidney Transplant;
Introduction;
The transplant of a single marginal kidney may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent. Episodes of acute rejection, medication toxicity , and effect of the recipient’s comorbidities on the transplanted kidney will adversely affect these limited functional nephrons.
The concept of trans-planting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
Dual kidney transplant carries a potentially higher risk of surgical complications because of the;
1- longer surgical procedure .
2- fold risk associated with double vascular and ureteric anastomoses .
History ;
The first adult dual kidney transplant (DKT) was in the United States in 1996 .
Which kidney is suitable or dual transplant ;
Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus. Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
Selection criteria for DKTs are still variable and center dependent. 1-Biopsy based criteria;
Needle biopsy is usually avoided by surgeons because of risk of;
1- bleeding .
2- arterio- venous fistula formation.
3- there might be an element of individual interpretation variations in biopsy scoring, despite a structured scoring system.
A-In 1999, Remuzzi and associates suggested ascoring system based on pretransplant biopsy for selection of a kidney for DKT.
This scoring exclude Kidneys with ;
1- macroscopic major vascular abnormality .
2-evidence of focal scarring .
B- In a review of UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005.
Donors were considered for DKT if glomerulosclerosis on biopsy between 15% and 50%.
2-eGFR based criteria;
To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead.
Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula;
1-donors with eGFR > 60 mL/min were considered for SKT.
2-Kidneys were discarded when eGFR was < 30 mL/min, and
3-eGFR between these results was an indicator for DKT.
Snanoudj and associates performed 81 DKTs using this protocol, with 2-year graft survival of 90%.
Who is a suitable recipient?
1-DKT is offered to patients 60 years or older.
2-Patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m.
Surgical technique;
Ipsilateral placement of both grafts is widely accepted and performed.
Graft and patient survival ;
Results of graft and patient survival, complications, and quality of renal function
provided by DKTs are comparable to SKTs
Complications ;
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality. Although there is a higher prevalence of vascular complications, mainly in the form of graft thrombosis, the overall complication rate with dual kidney transplant is comparable to single kidney transplant.
Rihab Elidrisi
2 years ago
According to this article ,it will increase the chance of transplantation and will reduce the waiting list ,but still DKY have a lot of area of debate and it is mainly depending on the center and the nephrologist physician .
This article give us some information about the DKT and the complication associated with it.
IF we speak about kidney suitability for DKT it depend on different approach;
UNOS data base of donor > 60 years, crcl >65ml/min, 2.5mg/dl serum creatinine, diabetic type 2, and hypertensive found 79.8% graft survival at 3 years, while the Italian series found 90.9% after 3 years also
Hobart and associates suggested En block kidney transplant if donor is less than 2 years
a Spanish group study with biopsy using those with 15%- 50% glomerulosclerosis and mean age of 75 ± 7 years found graft survival at 6 months to be 95%
Most of the data available is suggested the following criteria for the recipient :
matching donor age and size with recipient
recipient without previous transplantation
recipient with panel reactive antibodies titer< 50%
Isaac Abiola
2 years ago
SUMMARY
Introduction
The increasing general public acceptance of kidney transplantation as the best form of renal replacement therapy is due increase in surgical skills and the availability of potent immunosuppressives which has greatly increased the recipient and graft survival. In order to increase the number of available organs for transplantation, the use kidneys from donors with extremes of age has been recommended. However, episodes of acute rejection, CNI toxicity, and recipient background comorbidity will ultimately affect the marginal functioning kidneys, hence the concept of dual kidney transplant has been suggested. The theory is that two marginal kidneys will contain more good nephrons than single marginal kidney. Nevertheless, the procedure involved carries a higher vascular and ureteric risk with long duration of surgery in mostly elderly patient.
Suitable kidney for DKT
It is unfortunate that there is no general consensus or agreement on the kidney to be used for DKT as most criteria are center specific and depend largely on the attending physicians. However, few authors have reported their various experiences
Remuzzi and associates using donors with brain dead, > 60 years, diabetic, and <3g 24 hours proteinuria reported patient and graft survival of 100% in 6 months among their 24 DKT recipient participants
a Spanish group study with biopsy using those with 15%- 50% glomerulosclerosis and mean age of 75 ± 7 years found graft survival at 6 months to be 95%
UNOS data base of donor > 60 years, crcl >65ml/min, 2.5mg/dl serum creatinine, diabetic type 2, and hypertensive found 79.8% graft survival at 3 years, while the Italian series found 90.9% after 3 years also
Hobart and associates suggested En block kidney transplant if donor is less than 2 years
United Kingdom Kidney Advisory group have suggested kidney from > 70 years could be used as DKT if one of the following like, cerebrovascular death, hypertensive, diabetic, MI serum creatinine at retrieval >1.97mg/dl
Suitable recipient for DKT
-many authors suggested the following
matching donor age and size with recipient
recipient without previous transplantation
recipient with panel reactive antibodies titer< 50%
The surgical technique has been either bilateral Gibson or use of unilateral Gibson which is more accepted because of lesser surgery time and early recovery from surgery
Complications of DKT
renal graft thrombosis
wound dehiscence
UTI
ureteric stenosis
post operative MI
higher post operative admission
Conclusion
The use of marginal kidney as DKT has helped to increase kidney donation pool and the outcome has been favorable compared with SKT in term of graft and patient survival even among pediatric where En block method has been used. However, lack of unified criteria for selection of kidneys for DKT is still a challenge that must be overcome.
Summary of the article Dual Kidney Transplant
1996: The first adult dual kidney transplant (DKT) was in the USA, by Johnson and assoiates, with 100% patient and graft survival at 6 months;
a) older than 60 years.. and/or
b) long history of hypertension or diabetes.
c) cold ischemia time less than 30 hours.
They picked donors who had creatinine clearance levels between 80 and 40 mL/min and with kidneys that showed less than 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy. Pre-transplant biopsy scoring system Pre-transplant Biopsy Protocol
a) Glomerular Global Sclerosis: Based on 3 sections (First, Middle and Last if available), the number of globally sclerosed glomeruli expressed as percentage
0 None globally sclerosed
1 < 20% global glomerulosclerosis
2 20% – 50% global glomerulosclerosis
3 > 50% global glomerulosclerosis b) Tubular Atrophy
0 Absent
1 < 20% tubuli affected
2 20% – 50% tubuli affected
3 > 50% tubuli affected c) Interstitial Fibrosis
0 Absent
1 < 20% of renal tissue replaced by fibrous connective tissue
2 20% – 50% renal tissue replaced by fibrous connective tissue
2 > 50% of renal tissue replaced by fibrous connective tissue
d) Arterial and arteriolar narrowing: For the vascular lesions, if the changes are focal, the most severe lesion present gives the final grade
0 Absent
1 Increased wall thickness but to a degree that is less than the
diameter of the lumen.
2 Wall thickness that is equal or slightly greater to the diameter of the lumen.
3 Wall thickness that far exceeds the diameter of the lumen with extreme luminal narrowing or occlusion. Only biopsies with ≥ 25 glomerules considered for evaluation. Kidneys with evidence of acute tubular necrosis are not considered for DKT
When to consider DKT: 1. According to a review of UNOS database (2000 – 2005), donors were considered for DKT if any 2 of the following criteria present: a) Age greater than 60 years. b) Creatinine clearance greater than 65 mL/min. c) Rising serum creatinine greater than 2.5 mg/dL at retrieval. d) Chronic hypertension or type 2 diabetes mellitus. e) Glomerulosclerosis on biopsy between 15% and 50%.
2. Italian series of 100 unilateral DKTs performed between 2003 and 2009, allocation was based on: a) donor age (mean donor age was 72 ± 5 years). b) clinical and histologic findings. 3. To avoid biopsy-based decisions (Snanoudj and associates): the 2-year graft survival of this protocol is 90%. a) The eGFR (according to CG formula) in the donor as a criterion was used instead. 1) donors with eGFR > 60 mL/min were considered for SKT. 2) Kidneys were discarded when eGFR was < 30 mL/min. 3) eGFR between 30 – 60 was an indicator for DKT. b) Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. 4. United Kingdom Kidney Advisory Group: DKT to be considered from donors who are age 70 years or older if 1 or more of the following clinical risk factors were present: a) history of hypertension. b) myocardial infarction. c) type 2 diabetes mellitus. d) cerebrovascular event as cause of death. e) serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys). 5. Newcastle team experience (donors with Maastricht-II(15 donors) and Maastricht-III (8 donors) were reported): a) All kidneys had hypothermic machine perfusion. b) Pressure flow index, defined as flow per 100 grams renal mass divided by systolic blood pressure, and concentration of glutathione transferase, an enzyme marker of ischemic injury, in the perfusate were measured. c) Kidneys were used for SKT if pressure flow index was 0.4 mL/min per 100 g/mm Hg and glutathione transferase was less than 100 IU/L/100 grams renal mass. d) If pressure flow index was less than 0.4, kidneys were discarded. e) Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (eg, comorbidities or cold ischemia). f) The study showed delayed graft function rate of 81% but 3-month GFR of 46.2 ± 13.7 mL/min. who is a suitable recipient for DKT ? 1. Matching recipients with donors by age and size(suggested by many authors). 2. DKT is offered to patients 60 years or older. 3. The study’s group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2. 4. Selection criteria for DKTs are still variable and center dependent.
Surgical technique 1. A midline extraperitoneal approach, through midline infraumbilical incision, blunt dissection of extraperitoneal space bilaterally to expose iliac vessels. 2. Bilateral Gibson incision. 3. Unilateral modified Gibson incision in En Block Kidney(EBK) transplant in pediatrics. 4. Unilateral placement of both kidneys was described by Mason and Hefty in 1998. 5. EBK with 2 adult kidneys performed in the same manner as with pediatric donors was also described. An Iranian center transplanted adult kidneys en block.
Outcome of DKT 1. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs. 2. The use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomedespite the higher surgical complication rate. Complications of DKT 1. Complications with DKT are due to technical difficulties, with longer operative time and lower kidney quality; a) Early renal graft thrombosis. b) Urinary tract complications(ureteral complication or urine leak), especially urinary tract fistulas requiring surgery. c) Higher risk of developing MI when compared to SKT candidates. Possibly due to longer operative procedure and anesthetic time in addition to older recipient’s age. d) Wandering kidney is an interesting radiologic finding rather than a true complication. 2. A larger study also showed no differences in complication rates between ipsilateral DKT and SKT.
– Here, this is a review of the current experience of dual kidney transplantation. The hypothesis is that transplanting 2 kidney donors in one recipient especially if ECDs with marginal kidney, will allow for available more nephron mass & improve the outcome. The first adult dual kidney transplant was in the United States in 1996 by Johnson and associates. still there is no strong evidence or consensus regarding DKT & the fear of increased surgical complications makes some centre reluctant especially with lack of experience.
– Combination of biopsy results with use of remuzzi score, donor criteria ( age , hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event & eGFR) & DCD will affect the decision of which kidney is suitable for DKT .
– Generally , DKT is offered to patients 60 years or older. offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2 is also preferable.
– Unilateral Placement of the 2 kidneys is the preferable technique with many benefits regarding decreasing time of the surgery, keeping the other side untouched for possible another transplant & the complications are comparable to that of SKT , the author here prefer to extend the short right renal vein using the donor inferior vena cava anastomosed to the recipient’s inferior vena cava & use the common iliac artery as an inflow artery .
– Two large analyses of the UNOS database have been published. The 2008 report documented 625 DKTs performed between January 2000 and December 2005. Despite a longer cold ischemia time in the DKT group versus that shown for groups who underwent SKT with ECD and standard criteria donor, delayed graft function incidence was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors
– Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality. Unilateral placement of both kidneys reduces length of the surgical procedure and hospital stay. Ekser and associates reported 2% renal vein thrombosis in both the bilateral and ipsilateral DKT groups (total of 58 DKTs), and no difference in the complication rates between both techniques. A larger study also showed no differences in complication rates between ipsilateral DKT and SKT. The ipsilateral placement reduced dissection time and made lymphocele risk similar to that for SKT procedures
Conclusion :
– Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys.
– Unilateral placement of both grafts is widely accepted and performed. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
– Selection criteria for DKTs are still variable and centre dependent. There is reluctance of many canters to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide.
– More research should help to develop standardized criteria for DKT kidney allocation
This study is concerning dual kidney transplantation. Most centers perform unilateral kidney placement. Deciding to do dual kidney transplant is dependent on several factors. Due to the fact that dual kidney transplant is not performed regularly in many centers it is difficult to assess accurately which donor kidneys are best for this.
General characteristics of kidneys used for DKT include kidneys from brain dead donors, normal serum creatinine levels, above age of 60, glomerulosclerosis allowed unto 50% and BMI less than 30 kg/m2 with minimal co-morbidities. Graft survival can be good.
Older recipients are picked for DKT. This is because of the limited functioning nephron mass, limited metabolic demands, and the fact that expected lifespan would not be above 20 years. Recipients with lower immunological risk are better chosen for DKT such as those who did not undergo a previous transplant, and those with PRA titer less than 50%.
Operative method used for this is midline extraperitoneal approach.
DKT has good outcome with excellent creatinine levels and lower risk of acute rejection. This means that they can also be used in younger recipients and expected to have good outcome. In addition, an advantage is that younger recipients can recover quicker post transplant which is very helpful in the case of DKT.
Expected complications include longer operative time due to perceived technical difficulties and lower kidney quality. Early renal graft thrombosis can pose a serious complication. Urinary tract complications include urinary fistulas, urinary stenosis, vascular thrombosis. Post op complications in other areas include increased risk of myocardial infarction.
However, it is to be noted that mono lateral placement of both kidneys reduces the length of operative time as well as hospital stay. There is no difference in the incidence of complications in either approach. Ipsilateral placement is more widely accepted and done.
Use of pediatric kidneys by en block technique into adult recipients has good outcome for graft and patient, but the risk of complications is significantly higher.
Further research is needed to delineate which kidneys are to be selected for DKT, kidney allocation for which recipients, and standardized guidelines need to be developed so that DKT can become a more widely accepted and performed practice among transplant centers worldwide.
This article focus on indications and results of dull kidney donor in marginal kidney and extended kidney criteria to reduce waiting list for donation and improve quality of life in patients on dialysis for long time. Also due to super effectiveness of immunosuppressive therapy leading to increase incidence of survival graft.
Marginal kidney means older age more than 60 or less with history of diabetes and hypertension and serum creatinine level > 1.5. eGFR between 40 to 80ml/min. or evidence of cerebrovascular disease and causes of death are cardiac and circulatory arrest.
In 1999, Remuzzi groups suggest pretransplant biopsy for selection of a kidney for DKT.
Many centers not familiar with DKT. However survival rate with DKT 100% in first 6 months but risk of surgical procedure and complications of vascular anastomoses are doubled.
Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered. Kidneys with macroscopic major vascular abnormality or evidence of focal scarring (chronic pyelonephritis) were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. The study shows DKD graft survival was 100% at 6 months.
In a 2000 study by a Spanish group, kidneys from brain dead donors with normal serum creatinine levels were considered for DKT if donors older than 75 years old. Also donors between 60 and 74 years old with glomerulosclerosis between 15% to 50%.
In this study pre transplant biopsy done and Kidneys with less than 15% glomerulosclerosis were transplanted separately, and kidneys with greater than 50% glomerulosclerosis were discarded.
Consider DKT to recipients with lower immunologic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%.
Surgical technique mainly in right iliac fossa area, bilateral Gibson incision and transplanting one kidney to each side.
Ipsilateral placement of both grafts is widely accepted and performed and less wound infection.
The quality of DKT function is important since it will keep functioning for long time and keep the patient dialysis independent for as long as possible. Many factors affect graft function, including donor factors, donation circumstances, cold ischemia time, and perioperative events. Complications of DKT:
Thrombosis of renal graft
urinary tract infection
Renal transplant is the treatment of choice for patients with end-stage renal disease. To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
In late 2003, the United Network for Organ Sharing (UNOS) was implemented using kidneys from extended criteria donors (ECDs). Comprehensive criteria donors include donors older than 60 years or those older than 50 with a history of hypertension, who had a cause of death due to cerebrovascular events, or who have serum creatinine levels at retrieval of more than 1.97 mg/dL. In addition, donations after cardiac death have also been accepted worldwide as the source of organs despite being regarded as marginal due to their association with warm ischemic injury.
The concept of trans-planting both donor’s kidneys into one recipient as dual renal transplant has been adopted to increase available “nephron mass.”
The first adult dual kidney transplant (DKT) was in the United States in 1996 by Johnson and associates
which kidney is suitable for a dual transplant?
A dual kidney transplant is a waste of resources if a single kidney will keep the recipient dialysis independent.
In 1999, Remuzzi and associates suggested a scoring system based on pretransplant biopsy to select a kidney for DKT.
Dual kidney transplants were performed if the a priori score was between 4 and 6
Pediatric donors were first considered pediatric recipients. Because of increased surgical complications, inadequate nephron mass, relative sensitivity regarding rejection, and risk of hyperfiltration injury, pediatric SKT remains controversial
who is a suitable recipient?:
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size.
In general, DKT is offered to patients 60 years or older. Our group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m
Surgical technique
Johnson and associates6 described the first DKT; the original technique included bilateral Gibson incision and transplanting 1 kidney to each side. This method required more tissue dissection and a longer operative time. Because most recipients are 55 years or older, a reduction of total anesthetic, a shorter operative time, and fewer vascular anastomoses are desirable.
The closing of the aorta below the origin of renal arteries, with the donor inferior vena cava closed above the source of renal veins and the lower end used for anastomosis into iliac vessels
Joining both renal arterial patches into one and using an inferior vena cava patch to elongate the right renal vein and then attaching both veins into a common ostium to allow single arterial and venous anastomosis was also described
Graft and patient survival:
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality than the other kidney. Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery (17%; P = .06), although no significant difference in overall surgical complications was shown.
Conclusions:
Dual kidney transplant has increased the pool of potential organs by increasing the use of marginal kidneys. As a result, the ipsilateral placement of both grafts is widely accepted.
What about the New Castle method of decision for DKT
Abdul Rahim Khan
2 years ago
Please provide a summary of this article Dual kidney transplant is done when the donor is marginal and are placed in on recipient. It may improve the graft outcome. Technique Usually midline incision is given and both kidneys are placed extraperitoneally. Right kidney is placed over the left. the dual renal transplant is associated with higher complications as compare to single kidney transplant. Anastomosis are done as below- Right renal artery to Right Common illiac artery Right renal vein to – IVC Left renal artery to external illiac vein Left renal vein to external illiac vein. Both Ureters can be joined together and anastomosed to bladder or can be reimplanted separately . Kidney donation based on eGFR- e GFR > 60 ml/min- Single kidney donation eGFR 30-60 ml/min- Dual transplant eGFR < 30 ml/min – Cannot donate Kidney donation from marginal donors- History of diabetes, hypertension, age> 60 yrs, CVA, IHD, Proteinuria > 3 gm/day Donor kidney renal biopsy assesses the Glomerulosclerosis, interstitial fibrosis, tubular atrophy and arterial narrowing- The Remuzzi Score 0-3- Single kidney transplant 4-6- Dual renal transplant >6- Discard. Dual transplant- ideal recipient. Elderly recipient do better than younger ones PRA <5% First transplant BMI < 30 Less medical conditions. Conclusion- Dual transplant has increased donor pools. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs. Use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes Selection criteria for DKTs are still variable and center dependent.
Please provide a summary of this article REVIEW ARTICLE – EVIDENCE LEVEL V Introduction: Due to increased waiting list for kidney transplant in the last decades, the trend to accept donors from age extremes (pediatrics and older) donors, extended criteria donors(ECD) > 60 Years or > 50 Year old with history of HTN, cardiovascular cause of death, serum creatinine at retrieval of 1.97 mg/dl. Donors from cardiac death patients and pediatrics had nephron mass loss, which may be affected with episodes of acute rejection, immunosuppressive medications, and recipient’s comorbidities after kidney transplantation. Raise the dual kidney transplant idea in several transplant centers in order to over come these marginal kidneys outcome, the first dual kidney transplant done in USA in 1996 by Johnson and colleagues.
Which kidney is suitable for dual transplant? Several studies were published in dual kidney transplant with different protocols, with no obvious straight forward guidelines for such practice. Remuzzi and associates, suggested a scoring system based on pre-transplant biopsy for selection of a kidney for DKT. Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered. Kidneys with macroscopic major vascular abnormality or evidence of focal scarring were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. Dual kidney transplants were performed if a priori score was between 4 and 6. In the 24 DKTs reported in the study, patient and graft survival was 100% at 6 months. In a review of UNOS database published on 2008, 525 DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%. Three-year graft survival was 79.8%. The limitation is the surgeons take an elliptical biopsy from kidney surface, this due to the fear of bleeding or arterio – venous fistula formation in needle biopsies. This could be misleading and overestimate the glomerulosclerosis, as glomeruli sclerose from outside in, leads to excess in organ discard for marginal kidneys, thus, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead of biopsy. Donors older than 65 years with one of the following risk factors were considered: HTN, T2DM, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT. Snanoudj and associates performed 81 DKTs using this protocol, with 2-year graft survival of 90%.
Who is a suitable recipient? Matching age and size of donors and recipients in ECDs, best suggested for DKTs, they had nephron loss, less risk for rejection, limited life span for the elder recipients, this was ideal to low immunological risk recipients whom no history of previous transplant, and PRA <50%. DKT is offered to patients 60 years or older, offering DKTs to patients with low immunological risk, who are less than 60 years old, and minimal comorbidities and body mass index < 30 kg/m2 recipients.
Surgical techniques Different approaches were dicussed with the potential complications, special concern to kidneys from pediatric donors illustrated, however these procedures needs expert team to perform them, to decrease the complications risk.
Graft and patient survival Different data from several studies on patient and graft survival, but it was equivocal or better among DKTs versus SKTs. Surgical complications were more in DKTs.
Complications Higher postoperative admission rates to an intensive care unit (more among DKTs). Wound dehiscence (more among DKTs). Early renal graft thrombosis (more among DKTs). Urinary tract complications- fistulas, ureteric stenosis (comparable). Recipients of DKT have a higher risk of developing myocardial infarction (more among DKTs). Reduced dissection time and low lymphocele risk in ipsilateral DKTs versus bilateral DKTs. Infections were less among ipsilateral DKTs.
Conclusions DKTs increased the pool of potential organs by increasing use of marginal kidneys. Ipsilateral placement of both grafts is widely accepted with less complications comparable to SKTs. Graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs. Up to now no clear criteria to choose either DKTs vs SKTs among ECD, this make it wise to standardize criteria for DKTs allocation.
Well done but although the Remuzzi score is time consuming and not prefer Ed by some but proteinuria even less tha 3gm a biopsy is a must and might show surprises.
Introduction In the past few decades, dual kidney transplantation has enabled a larger use of kidneys that were considered to be on the verge of failing and has shortened the waiting period. Both the absence of a well-defined allocation policy and the fact that clinicians alone are responsible for making judgments about dual kidney transplants, are obstacles that prevent many centers from implementing DKT program. The implantation of both kidneys on one side is the approach that is preferred in many different centers. Although there is a higher incidence of vascular complications, primarily in the form of graft thrombosis, the overall complication rate is comparable between single and dual kidney transplants. Kidney survival and function are encouraging and close to results with a single kidney transplant using conventional criteria. One marginal kidney (from ECDs, donors with cardiac death, or pediatric donors) may not have enough functional nephrons to allow a receiver to become dialysis independent after transplantation. In order to expand the available “nephron mass,” the practice of transplanting both kidneys from a single donor into a single recipient as a dual renal transplant has gained popularity.
Which kidney is suitable for dual transplant?
One reason why DKTs are not commonly performed at many transplant hospitals is that there is no universal consensus on which donor kidney is best for DKT. In addition, there are distinct criteria for choosing kidneys due to the fact that surgical practices and protocols vary widely from one institution to the next. A total of 525 DKTs were reported between 2000 and 2005 in a review of the UNOS database published in 2008. Donors were selected for DKT if they fulfilled 2 out of the following 4 criteria: age >60, creatinine clearance >65 mL/min, serum creatinine >2.5 mg/dL and rising at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy 15%-50%. The three-year graft survival rate was 79.8%. Remuzzi and colleagues proposed a pretransplant biopsy-based grading system for selecting a kidney for DKT in 1999. Dual kidney transplants were performed for patients with an a priori score between 4 and 6. Six months after the 24 DKTs reported in the study, both patient and graft survival were 100%. In a 2000 trial conducted by a Spanish group, brain-dead donors with normal serum creatinine levels were considered for DKT if they were at least 75 years old. United Kingdom Kidney Advisory Group recommended that kidneys from donors aged 70 or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, MI, type 2 DM, CV event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
who is a suitable recipient?
Numerous authors recommend matching recipients with donors based on their age and size. Given that the majority of DKTs involve donors at extreme ages, it is proposed that older donors be paired with older recipients.
Surgical technique
Johnson and colleagues described the first DKT, which involved bilateral Gibson incisions and the transplantation of one kidney on each side. However, this technique requires more tissue dissection and loner operative time. A midline extraperitoneal approach was described to minimize dissection and operative time. Haider and associates described this technique in 2007.16 The single midline incision has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision. Unilateral placement of both kidneys was described by Mason and Hefty in 1998.
Graft and patient survival
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs. Lee and associates reported similar patient and graft survival at 1 year (98% and 89% in DKT vs 97% and 90% in SKT) and 2 years (86% and 77%). UNOS database from 2000 until 2005 followed 625 recipients of DKT for 48 months. Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%. A French team with older donors (age, 75 ± 5.8 y) recorded DKT patient and graft survival at 3 years that reached around 50%. In a study of ECD donors, D’Arcy and associates from Ireland reported superior 3-month patient (92% vs 100%) and graft survival (88% vs 93%) in recipients of SKT vs DKT.
Complications
Due to technical obstacles, longer operative time, and inferior kidney quality, complications with DKT are believed to be greater. Following complications were more frequently observed with DKTs.
local wound dehiscence Early renal graft thrombosis Urinary tract complications (fistulas requiring surgery) Ureteric stenosis Ureteral complication or urine leak Wound infection
1.Please provide a summary of this article Introduction
·A wide gap exists between the numbers of ESRD cases on the DKD waiting lists & the number of deceased donors available.
This fact has dictated the use of ECD for donation.
·Donor age was reported to have adverse effect on graft survival in most studies.
·Patient survival in the 1st & 2ndyear post-transplant were similar between ECD & SCD donors.
·However, graft survival & function were reduced with increased incidence of DGF & AR events.
·DGF & AR events are reported as risk factors for graft failure (Ferrer et al).
·Some studies reported that there is no significant relation between donor age & 5-year graft function.
·So, donors previously deemed as not suitable are now acceptable.
·This retrospective single center study reports outcomes of patients transplanted by kidneys from elderly donors (=/> 60). The study Population
All patients who received DKD grafts from elderly donors (=/> 60 at SKI between 3/1969 & 2/2009.
Exclusion criteria:
DKD transplants from donors < 60 years.
LKD transplants of any donor age.
Transplants before 3/1969 or after 2/ 2009. Aim
To determine graft & patient survival outcomes of kidney transplants from elderly donors. Donor factors:
Age
Sex
Serum creatinine
eGFR
CIT
HLA mm
HLA-DR only mm
Total follow-up,
Total duration of graft survival
Graft & recipient survival at 1, 3, & 5 years post-transplant
AR episodes Recipient factors:
Patient status (dead or alive)
Age
Sex
Co-morbidities (CVD, T2DM type 2, CVD, &HTN)
Type of IS agents used
Number of AR events
DGF
eGFR (MDRD equation) at 3, 12, & 60 months post-transplant.
Graft loss or non-graft survival was defined by a creatinine rise requiring RRT.
Recipient death was defined as non-patient survival.
Statistical analyses done with SPSS Software. Results
· A total of 112 TX were done during the study period.
· Total number of donors: 112 donors.
· 59 of the donors are females (52.7%).
· Mean donor age: 64.71 +/- 4.
· Of 112 recipients, 38 are females (33.9%).
· Patient survival at 1 yr was 91.9%, at 3 yrs 82.1 %, & at 5 yrs 78.2%.
· Graft survival at 1 yr was 80.4%, at 3 yrs 67.7%, & at 5 yrs 63.6%.
· Donor age ( P = .008) & donor serum creatinine level (P = .011) were significantly associated with total duration of graft survival.
· Age differences (P = .001), donor eGFR (P = .04), & donor age (P = .03) are predictors of total duration of graft survival. Donor eGFR & age had negative impact on graft survival.
·Better cumulative graft survival was associated with the use of kidneys from donors with eGFR of 60 mL/min as compared to those with eGFR <60 mL/min.
·In a multivariate analysis donor age was not a significant predictor duration of graft survival (P> .05), while AR events (P< .001) & donor eGFR (P = .035) significantly predicted cumulative graft survival. Discussion
·Expanding the criteria for deceased donors ECD was dictated shortage of donor organs for kidney transplant.
·Graft function was independent of age of the donor.
·The authors found no significant effect of donor age when considered with other donor variables (e.g. kidney function) & donor-recipient variables (DGF & AR).
·CIT, recipient co-morbidity, & total number of HLA mm are also not associated with any short or long term effect on graft survival.
·Opelz et al. (data from Collaborative Transplant Study) reported that HLA mm significantly affected the outcome of kidney transplants.
·Reisaeter et al.(655 non-sensitized recipients of DD grafts):
-1-yr HLA-DR m graft survival 90% vs 82% & 73% for 1 & 2 HLA-DR mm grafts.
– 5-yr survival rates were 76%, 62%, & 56%.
– HLA-A & HLA-B did not improve overall graft survival but improved graft survival at 1 yr.
·Moreira et al. (997 DD kidney transplants) reported an incidence of DGF of 19%.
·DGF was quite high (40.2%) in the current study; this may indicate that kidneys from elderly donors are more susceptible to DGF.
·Moreira et al. also report that DGF significantly reduced long-term graft survival without any effect on patient survival.
·In this study, DGF had no long-term effect in the elderly donors who were > 60 yrs.
· Donor eGFR has significant associated with duration of graft survival.
· The significant association between eGFR & graft survival may indicate that the quality of donor kidneys (eGFR) is more important than age.
· Ferrari et al. showed no significant effect of age difference on patient & graft survival in LDK transplant; however, the current study shows that age difference predicts graft survival. This may indicate a role for age difference in DKD transplants in the presence of other risk factors.
·High incidence of AR episodes in the study (33.9%) could be due to the high incidence of DGF or to reduction of IS therapy done to help the elderly kidneys recover from DGF.
·Patient survival in the study is comparable with other single center survival results. Conclusions
·Deceased elderly donors kidneys may significantly expand the donor pool if the associated risk factors are avoided.
·Better donor selection based on eGFR is related to better post-transplant function & better graft survival.
·Better HLA-DR m kidneys gives better outcome.
A shorter summary would be better
LDT as exclusion criterion?.????
but good work
Sherif Yusuf
2 years ago
Dual kidney transplant refer to transplantation of two kidneys from a marginal donor in one recipient that is theoretically may increase graft survival.
Technique
The best approach is through midline infraumblical incision and the 2 kidney are put at one site in the extraperitoneal region to reduce operation time with the right kidney above the Lt Kidney.
En bloc DKT can be done in transplantation of pediatric kidneys using donor aorta and IVC
The right renal artery is anastomosed to the common iliac artery
The Right renal vein is anastomosed to the IVC
The left renal artery is anastomosed to the external iliac artery
The let renal vein is anastomosed to the external iliac vein
Both ureters are joined together and the conjoint ureters are anastomosed to the urinary bladder with ureteric double J stent.
Technically operation is difficult and time consuming, associated with higher incidence of wound dehiscence, and associated with more post-operative complications especially vascular thrombosis and ureteric complications when compared to single kidney transplantation.
Ideal Donor for DKT should has the following 3 requirements
1- GFR
If GFR > 60 ml / min single kidney transplantation is selected
If GFR < 30 ml / min this donor is excluded
If GFR is between 30-60 this donor can be a candidate for dual kidney transplantation
2- Donor kidney should be a marginal kidney taken from the following type of patients:
Elderly patients > 60 years, or pediatric kidney
Patients with history of long standing hypertension, DM
Patient with proteinuria < 3 grams
Patients with history of myocardial infarction
Patients who died from cerebrovascular event
·
Kidneys with anatomical abnormalities (cysts, renal artery stenosis, kidneys with multiple arteries, small kidneys)
Damaged kidney (but still transplantable such as kidney with short artery, short vein, skinned ureter)
3- Donor renal biopsy
Addressing 4 parameters including assessment of glomerulosclerosis, interstitial fibrosis, tubular atrophy and arterial/arteriolar narrowing.
A score of 0-3 proceed to single kidney transplant
A score of 4-6 proceed for dual kidney transplant
A score of 7 or more discard these kidneys
Ideal recipient for DKT:
1) Age; elderly may be better candidates for DKT due to the following:
Elderly has lower immunological risk due to immunosenssense, but on the other hand they may not withstand long time of operation and complications that may occur post operatively
Dual kidney transplantation offer limited amount of functioning nephrons which will fit better with elderly recipient
2) Having lower immunologic risk (PRA less than 5%, first transplant)
3) Minimal co-morbidities especially atherosclerotic vascular diseases (due to technical difficulties in vascular anastomosis)
4) BMI less than 30 or body weight less than 80 kilograms (to prevent post-operative surgical complications like wound dehiscence)
Outcome
Outcome regarding patient, graft survival and DGF is the same when compared to single kidney transplantation, but with more incidence of CAN and more surgical complications.
The first adult dual kidney transplant (DKT) was in the United States in 1996 by Johnson and associates.
Two decades earlier, dual kidneys from pediatric donors had been transplanted into adults
Which kidney is suitable for dual transplant?
Dual kidney transplants were performed if Pretransplant Biopsy Scoring System priori score was between 4 and 6
Kidneys with prolonged warm ischemia time,
small kidneys, eGFR < 60 mL/min,
kidneys with multiple cysts,
kidneys from elderly donors (> 70 y),
donors who have a history of hypertension or type 2 diabetes mellitus.
Kidney donations after cardiac death
Kidneys were used for SKT if pressure flow index was 0.4 mL/min per 100 g/mm Hg and glutathione transferase was less than 100 IU/L/100 grams renal mass.
If pressure flow index was less than 0.4, kidneys were discarded.
Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (eg, comorbidities or cold ischemia).
Who is a suitable recipient?
Patients with low immunological risk,
who are less than 60 years old
who have minimal comorbidities
body mass index < 30 kg/m2
Surgical technique
midline extraperitoneal approach was described to minimize dissection and operative time Because the left iliac vein is in a deeper anatomic position, the left kidney with its longer renal vein was placed on the left side.
Unilateral placement of both kidneys :
Mason and Hefty1998:
Right kidney placed superiorly (RA–> CIA, RV –> IVC)
Clamps were released, allowing perfusion of transplanted kidney
Left Kidney (RA–>EIA, RV–>EIV)
The conjoint ureters were anastomosed to the bladder with ureteric double J stent. Esker method:
Right kidney placed superiorly(RV–>EIV)
Transplant ureters had 2 separate extravesical ureteroneocystostomies on ureteric stents. The upper kidney ureter was placed lateral to the lower kidney ureter.
Many surgeons now prefer this technique for DKT
Adv: Less dissection Authors preference:
Extend the short right renal vein using the donor inferior vena cava–>recipient’s IVC.
RA–> CIA En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
Outcomes:
Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
Use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes albeit with higher surgical complication rate.
y have all the information but with minimal organization.
Reem Younis
2 years ago
Please provide a summary of this article
-Renal transplant is the treatment of choice for patients with end-stage renal disease. To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
-Extended criteria donors include donors older than 60 years or those who are older than 50 with a history of hypertension, had cause of death due to cerebrovascular events, or have serum creatinine level
at retrieval of more than 1.97 mg/dL.
-The transplant of a single marginal kidney (from ECDs, donors with cardiac death, and pediatric donors) may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent. Episodes of acute rejection, medication toxicity (particularly from calcineurin inhibitors), and effect of the recipient’s comorbidities on the transplanted kidney will adversely affect these
limited functional nephrons.
-The concept of trans – planting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.” The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available versus with a single suboptimal organ or as many functioning nephrons versus with a single idealkidney.
– Transplanting 2 kidneys to the same recipient effectively prevents progressive deterioration in renal function compared with single
transplant controls.
– Dual kidney transplant carries a potentially higher risk of surgical complications because of the longer surgical procedure and the 2-fold risk associated with double vascular and ureteric anastomoses.
– Remuzzi and associates suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT.
– Five-year survival was 80% when protocol biopsy showed no glomerulosclerosis and dropped to 35% when sclerosis was > 20% in donated kidneys.
-Some authors also have reported higher delayed graft function (80%) with sclerosis > 20%.
-One of the limitations is that most surgeons obtain an elliptical biopsy from kidney surface. This could be misleading as glomeruli sclerose from outside in. As a result, these biopsies could overestimate
glomerulosclerosis. Needle biopsy is usually avoided by surgeons because of risk of bleeding or arterio – venous fistula formation.
– Greater use of kidneys for DKT that are more suitable for SKT could result in a reduced organ pool for transplant.
-To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead.
– Donors older than 65years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
-United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of
> 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
-Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus.
-Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
– Many authors suggested DKT with matching recipients with donors by age and size and recipients with lower immuno -logic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%).
-The earliest report of DKT documented 100% graft and patient survival in DKTs.
– The quality of DKT function is as important as how long it will keep functioning since the aim is to keep the patient dialysis independent for as long as possible. Many factors affect graft function, including
donor factors, donation circumstances, cold ischemia time, and perioperative events.
– In multivariate analysis, DKT had a protective effect against delayed graft function . Kidney discard rate was 3 times lower when the high-risk ECD kidneys were offered as DKT.
-Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality.
-Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery . The kidneys for DKT were from older donors; these more atherosclerotic vessels
might suggest this higher risk.
-Postoperatively, recipients of DKT have a higher risk of developing myocardial infarctions when compared to SKT candidates.
-Monolateral placement of both kidneys reduces length of the surgical procedure and hospital stay.
-A larger study also showed no differences in complication
rates between ipsilateral DKT and SKT.
-The ipsilateral placement reduced dissection time and made lymphocele risk similar to that for SKT procedures.
-Thrombosis of renal vein, artery, or even the donor’s aorta was observed.
● Dual kidney transplant has enabled greater use of marginal kidneys and reduced waiting time
● The overall complication rate with dual kidney transplant is comparable to single kidney transplant.
● Use of kidneys from donors from age extremes (pediatric or elderly) has been suggested for increase pool donors
● Dual kidney transplant carries a potentially higher risk of surgical complications
● Most of DKTs were from donors > 65 years
● which kidney is suitable for dual transplant?
* Donors older than 60 years
* Long history of hypertension or diabetes * Cold ischemia time less than 30 hours
* CrCl between 80 and 40 mL/min
* Kidneys showed < 40% GS without IF or arteriosclerosis on biopsy
* Rejected Single Kidney by other units
* Remuzzi criteria 4 – 6
● who is a suitable recipient?
* Older recipient > 60 year
* Lower immunologic risk low who are less than 60 years old, and who have minimal comorbidities and BMI < 30 kg/m2.
● Surgical technique
The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava. And left kidney vascular pedicle to external iliac vessels.
● En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
● Concerns related to pediatric EBK
* More difficult surgical anastomosis,
* Inadequate nephron mass
* Relative sensitivity of pediatric kidneys to rejection
* Hyperfiltration injury
● Complications :
* Early renal graft thrombosis
* Urinary tract complications
* A higher risk of developing MI in DKT recipiants
● Results of graft and patient survival, complications, and quality of renal function
provided by DKTs are comparable to SKTs
During the past decades, there have been major improvements in kidney transplant.
Better perioperative care and immunosuppressive agents have improved patient outcomes.
Renal transplant is the treatment of choice for patients with end-stage renal disease.
In late 2003, the United Network for Organ Sharing (UNOS) implemented the use of kidneys from extended criteria donors (ECDs).
Extended criteria donors include donors older than 60 years or those who are older than 50 with a history of hypertension, had cause of death due to cerebrovascular events, or have serum creatinine level at retrieval of more than 1.97 mg/dL.
Donation after cardiac death also has been accepted worldwide as source of organs despite organs regarded as marginal due to association with warm ischemic injury.
The transplant of a single marginal kidney (from ECDs, donors with cardiac death, and pediatric donors) may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent.
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available versus with a single suboptimal organ or as many functioning nephrons versus with a single idealkidney.
Nephron mass as a determinant of chronic allograft failure has been experimentally tested in animals, with results showing that increasing the size of viable nephron mass by transplanting kidneys to the same recipient effectively prevents progressive deterioration in renal function compared with single transplant controls.
The first adult dual kidney transplant (DKT) was in the United States in 1996 by Johnson andassoiates.
Two decades earlier, dual kidneys from pediatric donors had been transplanted into adults.
DKTs using different organ selection criteria and techniques.
Dual kidney transplant carries a potentially higher risk of surgical complications because of the longer surgical procedure and the 2-fold risk associated with double vascular and ureteric anastomoses.
Differences in practice among different centers, absence of clear guidelines and allocation policies, and the belief that these grafts are suboptimal can contribute to this reluctance.
In a review of UNOS practices by Gill and associates, between 2000 and 2005, DKTs from donors > 50 years old accounted for only 4% of transplants.Moreover, 54% of the kidneys from donors > 65 years old in the United States and 12% in Europe are discarded.
These limitations clearly indicate the need to expand DKT practice.
There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers.
In addition, protocols between different surgeons and centers have led to differencesin kidney selection criteria.
In the first DKT report, Johnson and associates 6 used kidneys from donors older than 60 years and/or long history ofhypertension or diabetes with cold ischemia time less than 30 hours.
They picked donors who had creatinine clearance levels between 80 and 40 mL/min and with kidneys that showed less than 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy.
Kidneys being rejected for a single kidney transplant (SKT) by other units were criteria.
The group reported 100% patient and graft survival at 6 months.6
In 1999, Remuzzi and associates suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT.
Brain dead donors older than 60 years, donors who were diabetic, or with of proteinuria of less than three grams/24 hours were considered.
Kidneys with macroscopic major vascular abnormality or evidence of focal scarring (ie, chronic pyelonephritis) were excluded.
Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. Dual kidney transplants were performed if a priori scorewas between 4 and 6 ز
Pretransplant Biopsy Scoring System Pretransplant Biopsy Protocol
Glomerular Global Sclerosis:
Based on 3 sections (First, Middle and Last if
available), the number of globally sclerosed glomeruli expressed as percentage
0 None globally sclerosed
1 < 20% global glomerulosclerosis
2 20% – 50% global glomerulosclerosis
3 > 50% global glomerulosclerosis
Tubular Atrophy
0 Absent
1 < 20% tubuli affected
2 20% – 50% tubuli affected
3 > 50% tubuli affected
Interstitial Fibrosis
0 Absent
1 < 20% of renal tissue replaced by fibrous connective tissue
3 > 50% of renal tissue replaced by fibrous connective tissue
Arterial and arteriolar narrowing: For the vascular lesions, if the changes are focal, the most severe lesion present gives the final grade
0 Absent
1- Increased wall thickness but to a degree that is less than the diameter of the lumen
2- Wall thickness that is equal or slightly greater to the diameter of the lumen
3 -Wall thickness that far exceeds the diameter of the lumen with extreme luminal narrowing or occlusion
Only biopsies with ≥ 25 glomerules considered for evaluation. Kidneys with evidence of acute tubular necrosis are not considered for DKTز
In the 24 DKTs reported in the study, patient and graft survival was 100% at 6 months.
In a 2000 study by a Spanish group, kidneys from brain dead donors with normal serum creatinine levels were considered for DKT if donors older than 75 years old.
In addition, donors between 60 and 74 years old with glomerulosclerosis of 15% to 50% at biopsy also were included.
. Kidneys with less than 15% glomerulosclerosis were transplanted separately, and kidneys with greater than 50% glomerulosclerosis were discarded.
Mean donor age in the study was 75 ± 7 years. Graft survival at 6 months was 95% in 21 recipients.
Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%.
Three-year graft survival reached 90.9%.8
Severe histologic findings are associated with impaired allograft function and are the rationale of using biopsy to determine suitability of marginal kidneys.
Five-year survival was 80% when protocol biopsy showed no glomerulosclerosis and dropped to 35% when sclerosis was > 20% in donated kidneys. also have reported higher delayed graft function (80%) with sclerosis > 20%.
One of the limitations is that most surgeons obtain an elliptical biopsy from kidney surface.
In the Spanish series, of the 21 DKTs recipients had single kidney thrombosis.
Renal function was maintained in 3 of recipients by the single nonthrombosed kidney raising the questionwhether the patients should have received SKT
DKT that are more suitable for SKT could result in a reduced organ pool for transplant.
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size.
Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
In general, DKT is offered to patients 60 years or older.
Our group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities andbody mass index < 30 kg/m.
Original technique included a bilateral Gibson incision and the transplanting of 1 kidney to each side. This method required more tissue dissection and a longer operative time.
A midline extraperitoneal approach was described and it has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision. In addition, a potential wound infection would be far away from the graft.
Pediatric kidneys have a higher risk of surgical complications, especially vascular as a result of small vessel size. En block kidney transplant using a pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
==================================================================== Graft and patient survival
DKT documented 100% graft and patient survival in 9 DKTs.
Although the meanfollow-up was short (6 months; range, 2-14 months), recipients of DKT had better graft function than both control groups (recipients of SKT from donors > 60 y or from donors < 50 y).
Lee and associates14 suggested an older donor for older recipient strategy. They reported similar patient and graft survival at 1 year (98% and 89% in DKT vs 97% and 90% in SKT) and 2 years (86% and 77% in DKT vs 95% and 86% in SKT; P = not significant).
The 2007 review of the UNOS database from 2000 until 2005 followed 625 recipients of DKT for 48 months.
Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%.
During the same follow-up, recipients of kidneys from standard criteria donors had better survival of 80%.
A French team with older donors (age, 75 ± 5.8 y) recorded DKT patient and graft survival at 3 years that reached around 50%.10 In a study of ECD donors, D’Arcy and associates24 from Ireland reported superior 3-month patient (92% vs 100%; P = .05) and graft survival (88% vs 93%; P = .02) in recipients of SKT vs DKT.
On pediatric kidneys transplanted into adults as EBK have shown encouraging results.
A review of the UNOS database from 1987 to 2003 reported results of 2160 recipients of EBK.
The report showed that 77% of EBKs were from donors < 5 years old; however, graft survival at 1, 3, and 5 years was superior (85%, 76%, 71%) versus SKT (81%, 68%,63%; P = .001).
Complications with DKT are perceived to be higherdue to technical difficulties, with longer operative time and lower kidney quality.
Lee and associates14 reported a local wound dehiscence rate of 5% in their series of 41 DKTs.
Early renal graft thrombosis is a cause of concern in DKT.
In a report, 5 kidneys (12%) of 42 transplanted kidneys showed thrombosis. One patient had bilateral thrombosis, and 3 recipients had single kidney thrombosis but with renal function preserved by the other kidney.
Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery (17%; P = .06),
Although no significant difference in overall surgical complications was shown.
In a French report, 11% of recipients had ureteric stenosis and a similar rate ofurinary fistula.
The kidneys for DKT were from older donors; these more atherosclerotic vessels might suggest this higher risk.
Postoperatively, recipients of DKT have a higher risk of developing myocardial infarctions (12% vs 0%; P = .002) when compared to SKT candidates. Longer operative procedure and anesthetic time in addition to older recipients might provide an explanation.
Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys.
Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate.
The main question is which kidney is more suitable as DKT or SKT.
Selection criteria for DKTs are still variable and center dependent.
There is reluctance of many centers to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide.
More research should help to develop standardized criteria for DKT kidney allocation.
Summary
This study reviews the current practice for Dual kidney transplantation (DKT), there is no standardized guideline for DKT, and most of the evidence available from local centers’ experience, and the decision for DKT is based on clinical judgment with preferred surgical techniques of unilateral grafting or en block transplantation more in the pediatric population taken in consideration the vascular complexity, the graft and patient survival are comparable to the outcome of SKT but surgical complication including vascular thrombosis should be taken carefully in DKT.
The DKT started in 2003 according to the data from the united network of organ sharing (UNOS ) as part of ECD selection and after cardiac death with marginal kidneys from ECDs, pediatric donors with low nephron mass and prolonged warm ischemia time which further affects the limited nephron mass by CIT, acute rejection drug toxicity ( CNI ) and recipients comorbidities which can impact the graft survival and outcome so the concept of DKT in one recipient in order to raise the functioning nephron mass which has been confirmed from animal and human studies that increasing the size of viable nephron mass successfully improved graft function.
No consistent allocation criteria for DKT, it depends on the local center-based experience with diverse allocation criteria
UNOS database registry reported in 2008 data of 525 DKT surgery done between 2000-2005 and the selection criteria for DKT based on donor age > 60 with creatinine clearance > 65ml/min and raising creatinine > 2.5mg/dl at the time of organ retrieval, along donors’ history of HTN, DM type2 and biopsy score of GS 15-50% with 3-year survival was almost 80%.
In another Italian series of 100 DKT done between 2003-2009, allocation criteria were based only on donor age with, the mean donor age being 72 and true cut biopsy histological criteria between 4-6 for DKT and again the overall three-year graft survival was 90%.
Donors selected between the age of 60-69years with creatinine clearance above 60ml/min, and negative medical history for DM, HTN with normal serum creatinine no pre-OP biopsy indicated, and can be selected for SKD (esker and associate)
Kidney biopsy pre-OP has its limitations being invasive with the associated risk of bleeding and AVF in addition to variation in reporting these biopsies might be misleading and result in unnecessary organ discard so alternative to that some centers use the clinical donor’s criteria along with e GFR level by Cockcroft gault formula.in donors above the age of 65years with one or more of the medical comorbidities like HTN, type 2DM, death with CVA or CVD
GFR > 60ml/min for SKD
GFR 30-60ml/min allocation for DKT
GFR < 30ml/min the organ should be discarded
The above selection criteria were Studied by Snanoudj in 81 DKT with 2 years graft survival reached 90%
UK kidney advisory group proposes that donors above the age of 70s with a medical history of one or more of HTN, MI, type 2 DM, or CVA as the cause of death with a serum creatinine of 1.97mg/dl at the time of donation, presence of any anatomic variance (like RAS, PCKD) Small size kidneys) preferred to be used for DKT
Another group from Newcastle the use hypothermic machine perfusion pressure index as part of the selection criteria for DKT in donors from Maastricht categories 2, 3 with glutathione transferase level ( one enzyme marker for ischemic injury ).
Surgical complications of DKT
include longer procedures in compromised recipients lead to a higher rate of post-operative ICU admission, especially with double vascular and ureteric anastomosis, and vascular thrombosis, and the surgical complication even more in pediatric enblock procedures due to technical difficulties with vascular anastomosis and longer operative time, space in case of size difference with risk of functional and structural hyperfiltration and Secondary FsGS, urinary tract surgical complications with fistulas and ureteric stenosis.
Selection of the recipients for DKT
preferred to be age and size mass match, less comorbid diseases, low immunological risk means no previous transplantation and PRA < 50% this will allow to spare them the CNI toxicity risk with the use of CNI minimization or CNI free protocol
Summary:
Renal transplant is the treatment of choice for patients with end-stage renal disease. All over the world, there is a shortage of organs available for donation. To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested. In late 2003, UNOS implemented the use of kidneys from extended criteria donors. Donations after cardiac death also have been accepted worldwide.
The transplant of a single marginal kidney may result in a suboptimal number of functional nephrons to allow recipients to become dialysis-independent. The concept of transplanting both donor kidneys into 1 recipient as a dual renal transplant has been adopted to increase available “nephron mass.
which kidney is suitable for a dual transplant?
There is so far no global consensus as to which donor’s kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers. In addition, the variations in practice and protocols between different surgeons and centers have led to differences in kidney selection criteria.
In the first DKT report, Johnson and associates used kidneys from donors older than 60 years and/or long history of hypertension or diabetes with cold ischemia time less than 30 hours.
In 1999, Remuzzi and associates4 suggested a scoring system based on pretransplant biopsy for the selection of a kidney for DKT.
In a 2000 study by a Spanish group, kidneys from brain-dead donors with normal serum creatinine levels were considered for DKT if donors were older than 75 years old.
In a review of the UNOS database published in 2008, five hundred twenty-five DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria were present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%.
In another large Italian series of 100 unilateral DKTs performed between 2003 and 2009, the allocation was based on donor age and clinical and histologic findings.
To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead. Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with the use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as the cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
Pediatric donors were first considered for pediatric recipients. Because of increased surgical complications, inadequate nephron mass, relative sensitivity regarding rejection, and risk of hyperfiltration injury, pediatric SKT remains controversial.
who is a suitable recipient?
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size.
In general, DKT is offered to patients 60 years or older, patients with low immunological risk who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2.
Surgical technique
the original technique included a bilateral Gibson incision and the transplanting of 1 kidney to each side. This method required more tissue dissection and a longer operative time.
A midline extraperitoneal approach was described and it has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision. In addition, a potential wound infection would be far away from the graft.
Pediatric kidneys have a higher risk of surgical complications, especially vascular as a result of small vessel size. En block kidney transplant using a pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
Graft and patient survival
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs.
Lee and associates suggested an older donor for an older recipient strategy. They reported similar patient and graft survival at 1 and 2 years.
The 2007 review of the UNOS database from 2000 until 2005 followed 625 recipients of DKT for 48 months. Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%. During the same follow-up, recipients of kidneys from standard criteria donors had better survival of 80%.
A French team with older donors (age, 75 ± 5.8 y) recorded DKT patient and graft survival at 3 years that reached around 50%.
reports on pediatric kidneys transplanted into adults as EBK have shown encouraging results. A review of the UNOS database from 1987 to 2003 showed that 77% of EBKs were from donors < 5 years old; however, graft survival at 1, 3, and 5 years was superior to SKT.
Complications
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality.
Early renal graft thrombosis is a cause of concern in DKT.
y. Lee and associates reported a local wound dehiscence rate of 5%.
Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery.
a radiologic finding rather than a true complication is a “wandering kidney reported in a patient with abdominal pain and elevated serum creatinine level.
Kidney transplantation proved to be the treatment of choice for patients suffering from End Stage Kidney Disease (ESKD) as it will improve the quality of life and decrease mortality. However, the global shortage of suitable organs for transplantation remains a major obstacle.
One possible solution was to use double kidney transplantation (DKT) of a marginal kidney that would have been unsuitable for single kidney transplantation (SKT). Johnson and his colleagues performed the first adult DKT in 1996 after about two decades of the first paediatric DKT. Afterwards, several approaches to DKT were adopted by different centres.
DKT was not a popular option due to many reasons, which include: complex technique (double ureter and vascular anastomosis), prolonged operative time, higher peri-operative complications, and lack of standard criteria for DKT (regarding both donor and recipient criteria). However, the introduction of the Remuzzi score in 1999 provided a helpful tool for allocating deceased kidneys to DKT or SKT based on kidney biopsy findings.
Possible surgical techniques for DKT:
· Bilateral Gibson incision and transplanting of one kidney to each side:
Described by Johnson and associates. The technique was associated with prolonged operative time and more dissection for bilateral placement of allografts, which significantly increased peri-operative complications.
· A midline extraperitoneal approach:
A midline infra-umbilical incision with blunt dissection of extraperitoneal space to expose the iliac vessels bilaterally, and then one allograft will be placed in each side. This technique had the advantages of shorter operative time and lower risk of incisional hernia. Additionally, whenever there is wound infection, it will be away from the allograft.
· Unilateral placement of both kidneys:
In this technique, the right kidney allograft was placed superior to the left kidney, with the arterial anastomosis to the common iliac artery for the right kidney and the external iliac artery for the left allograft. The venous anastomosis for the right kidney will be with the IVC, and the left allograft with the external iliac vein. This technique had lowered the operative time further. Moreover, this approach preserved the contra-lateral iliac vessels for any future transplantation whenever needed.
· En block kidney transplant:
A technique that was initially described in paediatric DKT. This technique utilizes the donor aorta and IVC to be anastomosed with the external iliac artery and vein.
Patient and allograft survival:
Generally speaking, the overall patient and allograft survival with DKT from ECD were comparable to SKT from SCD. The primary documented complications were mainly related to surgical complications due to the challenging operative demands, wound infection, anastomotic leak and allograft vascular complications. Nevertheless, other factors may also affect the outcome as the donor age, prolonged cold ischaemia time, and donation circumstances.
Study designs and level of evidence:
This article is a narrative review which makes it level 5.
Limitations of the study:
The study is a review of retrospective, single-centre trials with no standardization of the donor or recipient characteristics. Therefore, the data provided needs more validation through more organized prospective trials.
Very good but you missed the UK Kidney Advisory Group method which is more practical tha than the Remuzzi score which will make an impact on the second WIT
Eusha Ansary
2 years ago
To mitigate the need for kidney recipients, dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys. This review article showed, graft and patient survival, complications, and quality of renal function provided by dual kidney transplants are comparable to standard kidney transplants. Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate. Donor age, clinical and histopathological findings, baseline renal function, should take into consideration.
Due to the emerging era of using marginal kidnies with lackage of organs , transplant physicians started to think about usage of dual kidney transplant.
No allocation scheme approved from the physicians to such kind of kidneis worldwide and it is a clincal based dependenet.
Dual kidney transplant carries a potentially higher risk of surgical complications because of the longer surgical procedure and the 2-fold risk associated with double vascular and ureteric anastomoses .
In 1999, Remuzzi and associates suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT. Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered .
One of the limitations is that most surgeons obtain an elliptical biopsy from kidney surface, this could be misleading as glomeruli sclerose from outside in,As a result, these biopsies could overestimate glomerulosclerosis .
The estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead .
United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys) .
Sutiable recipent can be old with to low metabloic activity with dcresed requriments of nephron mass, low immunological risk with usage of low target levels of CNI.
UNOS database shown that recipients of DKTs from ECDs had similar death-censored graft survival and also showed that 77% of EBKs were from donors < 5 years old, graft survival at 1, 3, and 5 years was superior (85%, 76%, 71%) versus SKT.
Complications with DKT are perceived to be higher ,like (wound dehiscence rate of 5% ,urinary tract comaplictions like urinary fistula,post transplant MI,higher EBK complication rate )
Very good but please revise the UK Kidney Advisory Group as you did not mention the eGFR to start with!
Doaa Elwasly
2 years ago
Introduction
ECD have been an option to face the increased demand of organs due to the shortage of available organs .
Organs retrieved from DCD donors are considered as marginal organs due to the warm ischemia time.
Transplanting a single marginal kidney from an ECD ,or DCD or paediatric donor provides insufficient functional nephron mass for recipients therefore dual kidney transplantation (DKT)policy was adopted to get use of those marginal kidneys by increasing the number of functioning nephron by transplanting to suboptimal kidneys in a single recipient and decrease the waiting list candidates.
DKT is carried out in multiple centres by variable techniques and organ selection criteria.
Although it carries high potential risks of surgical complications , it’s results are acceptable.
Absence of definite guidelines ,allocation criteria and suboptimal grafts lead to the reluctancy of different centres to apply DKT policy. Kidneys suitable for DKT
There are no standerdised criteria available for organ selection for DKT.
Johnson et al used kidneys from donors elder than 60 years with hypertension or diabetes history, having cold ischemia time < 30 hours, with creatinine clearance ranging from40 -80 mL/min and with kidneys < 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy they demonstrated that at 6 months the patient and graft survival were 100%.
Remuzzi at al,1999 designed a scoring system depending on biopsy done before transplantation to select a kidney for DKT . DBD donors > 60 years whom were diabetic, or with proteinuria < 3grams/24 hours were included excluding kidneys with less than 25 glomeruli and those with vascular anomalies.DKT was done if a priori score was between 4 and 6.
DKT was performed in 2000 in Spain from DBD donors with normal serum creatinine , aged >75 y and 60-74 y with 15%-50% glomerulosclerosis were included but they transplanted kidneys with <15% glomerulosclerosis and discarded those with > 50 % glomerulosclerosis .
In 21recipients at 6 months graft survival was 95%.
UNOS at 2000 studied 525 DKT cases within 5 years and found that graft survival was 79.8% at 3 years .
In Italy unilateral DKT was performed and results revealed graft survival of 90.9% at 3 years .A truecut needle was used for biopsies.
Protocol biopsy that showed no glomerulosclerosis had 5 years graft survival of 80% and decreased to 35% when sclerosis was > 20% in the kidneys.
There are some limitations as needle biopsies are not preferred due to bleeding risk and AV fistula formation that can occur also biopsies can overestimate glomerulosclerosis along with variable interpretation.
Unexpectedly the increased use of kidneys for DKT
that are more fit for SKT could lead to reduction of organ pool for transplant.
eGFR was used now to avoid decisions depending solely on biopsy results.
eGFR > 60 mL/min were considered for SKT, eGFR < 30 mL/min was discarded, and eGFR between these results was an indicator for DKT form donors> 65 y with certain risk factors.
Using such a policy 2-year graft survival reached 90% in 81 DKT cases.
The advisory kidney group in UK adviced that donors aged 70 years or more can be included in DKTs
if 1 or more of these risk factors were found as hypertension history ,MI , type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level > 1.97 mg/dL at retrieval, or any anatomic anomaly presence.
Some centres add to it prolonged warm ischemia time, , eGFR < 60 mL/min, kidneys with multiple cysts.
New Castle team documented in 2008 results of DKT outcome of donors with Maastrichit category 2 and 3 having HMP.Donors were chosen for SKT or DKT according pressure flow index and glutathione transferase,DGF rate was 81% but 3-month GFR was 46.2 ± 13.7 mL/min.
Pediatric SKT is debatable. Hobart et al adviced using en block kidney transplant when donor age is < 2 years. Appropriate recipients
It is controversial too but it was suggested to match recipients and donors according to age and size.
Others adviced to consider elder recipients due to their lower life expectancy and acute rejection rates and those with low immunological risk.
Contrarily others considered younger recipients as they will cope better with the longer operative time needed for DKT . Surgical technique
A midline extraperitoneal approach was introduced
to minimize dissection and operative time in comparison to the classical method added to this it can be turned to intraperitoneal approach, on the other hand it has higher ileus and bowel complications,
mobile grafts, and taking a biopsy will be more difficult.
In 1998 Mason and Hefty reported the unilateral placement of both kidneys preserving the other side for possible future transplantation and having similar 1 year graft survival as bilateral technique and less operative period taken.
Ekser et al introduced some modifications that lead to renal vein thrombosis in 2 of the studied cases in the unilateral group. This technique has shorter operative time and hospital stay and a lower GDF compared to bilateral technique of DKT .
Also unilateral DKT had similar outcomes to SKT .
Pediatric kidneys are at higher risk of complications.
EBK modification was introduced by NewCastle team by transposing the infrarenal aortic and IVC segment of the donor to the top, and the new inferior stump was stitched. The new vascular pedicle was anastomosed to iliac vessels, so that kidneys can drop to the extraperitoneal pelvic space, with favourable results. Graft and patient survival
DKT recipients had better graft function than recipients of SKT from donors > 60 y or from donors < 50 y.
The 2007 UNOS review within 5 years following cases for 48 months ,the recipients of DKTs from ECDs had similar death-censored graft survival, that was 70% and recipients of kidneys from standard criteria donors had better survival of 80%.
In a French study ,using older donors the DKT patient and graft survival at 3 years was nearly 50%.
A Spanish report mentioned that DKT and SKT from old donors nearly had the same graft and patient survival outcome at 1 year interval opposite to an Irish study that reported SKT to have a better graft and patient survival in a 3 months period but follow up at 3 years showed that the outcome was comparable to DKT from ECD.
EBK transplant of paediatric donors into adults had acceptable results.
The quality of DKT function is mandatory to be sufficient to keep the recipient dialysis independent.
This is affected by multiple factors as donor factors, donation circumstances, cold ischemia time, and perioperative events.
The UNOS 2008 report published that DKT recipients whom experienced prolonged cold ischemia time , had lower DGF than SKT from ECD and similar to SKT from standard donors.
For DKT recipients , PNF was 1.8% .
New Castle study demonstrated similar e GFR at 3 and 12 months posttransplant for DKT from DCD donors compared to SKT.
En block kidney transplant was associated with slight increased risk of graft loss compared to SKTs.
Paediatric EBK has more difficulties as surgical anastomosis increasing complications risk, low nephron mass, more liability to rejection, and
hyperfiltration injury that can lead to FSGS. Complications
DKT complications are higher due to technical difficulties, and longer operative time and lower kidney quality.
These complications include wound dehiscence ( reported in 5% ) , early renal graft thrombosis ,urinary tract fistula, vascular thrombosis,postoperatively recipients were more liable to MI.
It was reported that there is no differences in complication rates between ipsilateral DKT and SKT.
Studies demonstrated higher complication rates for EBK compared to SKT.
Wandering kidney can mislead diagnosis . Conclusion
DKT from marginal donors increased the pool of organs available.
Unilateral placement of both grafts have comparable outcomes to SKT.
Standardized criteria is needed for DKT kidney allocation.
The demand for renal transplants increases as the number of patients on the waiting list is rising. In the last decade, major advancements in kidney transplantation occurred, and the use of marginal kidneys is increasingly acceptable to fill the gap between demand and supply.
The transplant of a single marginal kidney (from ECDs DCD / DBD or pediatric donors) may result in a suboptimal number of functional nephrons, and nephron mass is a determinant of long-term graft function. Therefore, dual kidney transplantation evolved by using 2 marginal kidneys in the same recipient to increase nephron mass.
Several reports showed the acceptable outcome of using DKT. There are no clear guidelines, allocation policies, and practice varies among centers.
Which kidney is suitable for a dual transplant?
There is so far no consensus for DKT selection criteria, variation in protocol and practice among centers.
Remuzzi scoring system based on pre-transplant biopsy to select a kidney for DKT. Both kidneys were biopsied, and DKT was done if score was between 4-6. Sometimes, biopsies overestimate glomerulosclerosis when taken superficially.
Incorporating donor age and clinical and histologic findings for better decisions.
Another approach to use maximal eGFR calculated along with clinical data on comorbidities donors with eGFR > 60 mL/min were considered for SKT when eGFR 30-60 indicate DKT, and if eGFR < 30 Kidneys were discarded.
Hypothermic machine perfusion can guide the decision by measuring Pressure flow index and glutathione transferase GST concentration.
Kidneys were used for SKT if the pressure flow index was 0.4 mL/min per 100 g/mm Hg and GST was less than 100 IU/L/100 grams renal mass.
The kidneys were discarded if the pressure flow index was less than 0.4.
Kidneys were considered for DKT if the pressure flow index was satisfactory, but GST was higher than the cutoff value for SKT or if other risk factors were present (e.g., comorbidities or cold ischemia).
Using en block kidney transplant (EBK) when the donor ages less than 5 years.
Who is a suitable recipient?
– Matching recipients with donors by age and size.
– Elderly individuals have limited metabolic demands would not require graft survival of greater than 20 years
based on their expected lifespan; therefore, using kidneys with limited nephron mass is justified.
– DKTs to recipients with lower immunologic risk (recipients without previous transplant and PR < 50%), to reduce possible injury to limited nephron mass.
– Preferably offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and BMI < 30 kg/m2.
Surgical technique:
– Bilateral Gibson incision and transplanting 1 kidney to each side; more dissection and a longer OR time.
– A midline extraperitoneal approach with bilateral implantation; shorter OR time and dissection and fewer hernia
– Unilateral placement of both kidneys, the contralateral side remained untouched for possible future transplant
Graft and patient survival
Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%.
During the same follow-up, recipients of kidneys from standard criteria donors had better survival of 80%.
UNOS database showed that DGF incidence (29.3%) was lower than shown in recipients of SKT from
ECD (33.6%) and similar to recipients of SKT from standard criteria donors (28.3%). Primary nonfunction was as low as 1.8%.
Outcomes of EBK UNOS database showed a slightly increased risk of graft loss (aHR, 1.18) compared to SKTs. DGF was reported in 17.9% of EBK, with 23.44% in the SKT arm.
Complications:
Challenges includetechnical difficulties, longer operative time and lower kidney quality.
– local wound dehiscence rate of 5%.
– Early renal graft thrombosis 12%
– Urinary tract complications; fistulas requiring surgery, ureteric stenosis.
– Myocardial infarctions (12% vs 0%); in recipients of DKT when compared to SKT candidates. Explained by longer operative procedures and anesthetic time in addition to older recipients.
– In EBK, vascular complications were due to smaller vessels
Of course renal transplantation either from living or deceased donor is the best option and solution for CKD stage 5 on dialysis, as the dialysis is associated with increased morbidity and mortality, also it cost is higher than the cost of transplantation so it has financial burden on the government and also psychological burden on the patients themselves.
The number of patients on dialysis increasing every year because of increased incidence of diabetes, hypertension and obesity, and this is not matched with availability of transplantation as a solution to improve quality of life because of lack of donors, so the only option in that context to expand the donor pool to increase number of transplanted patients to match the rise in the numbers of patients being on dialysis and to decrease the waiting time staying on dialysis and shorten the transplant waiting list.
Many options brought to expand the donor pool like deceased kidney donor with expanded criteria like old age donor, donation after cardiac death, history of hypertension or diabetes or even acute renal impairment like AKI acute kidney injury.
The recipient, who received such ECD expanded criteria donor mostly old age, has low immunological profile, patient with running out vascular access, and small size patient like female or small size male.
These criteria of ECD yields suboptimal graft function and outcome, more DGF delayed graft function and more PNF primary nonfunctioning graft, so to increase the nephron mass to improve GFR to make the patient dialysis independent and to improve graft outcome and graft and patient survival , we can do DKT dual kidney transplant means transplanting both donor kidneys in a single recipient and this approach has more than one technique.
Biopsy can be done for the kidney donor pre-transplant to decide whether discarding or not the kidney donor based on the scoring system called Remuzzi score depends on the percent of glomeulosclerosis, tubular atrophy , interstitial fibrosis and vascular changes like arterial or arteriolar narrowing, this also will help to make a decision for DKT.
DKT can be done on both sides or transplanted unilateral as both kidneys were put in one side right kidney lying superior to the left kidney with anastomosis of renal artery to common iliac artery and renal vein to inferior vena cava and left kidney renal artery and vein anastomosed to external renal artery and vein, both right and left ureters are joined together then anastomosed to the urinary bladder, this technique is better than bilateral transplant both kidneys as it has lower surgical complications, lesser operative time.
Complications can happen like bleeding, graft thrombosis , renal vein or artery thrombosis, urinary fistula, also DKD for pediatric kidneys is associated with higher thrombotic complications because of small size vessels.
What are the the other simpler ways to help choose SKT or DKT ,you can find in the article
Filipe Prohaska Batista
2 years ago
This is a narrative review study discussing the importance and impact of double kidney transplantation and comparing several articles showing their experiences.
With the extended criteria donor concept established by UNOS in 2003, the availability of organs has increased, but often with a marginal response and smaller renal masses. Added to this is the concept of cardiovascular deceased donors, increasing warm ischemia time. In this context of criteria that increase the risk of late graft response, there was the idea of increasing kidney mass by providing two instead of one kidney from the same donor.
DKT has a higher risk of surgical complications due to the high warm ischemia time added to a greater number of anastomoses and tissue injuries, being twice as risky as SKT.
Johnson et al used donors older than 60 years with a history of SAH or DM with cold ischemia time of fewer than 30 hours. CrCl between 80 and 40mL/min and less than 40% glomerulosclerosis with 100% six-month survival.
Remuzzi et al established histopathological criteria in patients over 60 years of age, diabetic, and with proteinuria less than 3g in 24h, excluding patients with insufficient biopsies (< 25 glomeruli) or signs of organ ischemia. 100% survival at six months.
Andres et al considered patients over 75 years of age or between 60 and 75 years of age with 15-50% glomerulosclerosis. Six-month graft survival was 95%.
UNOS considered over 60 years of age, CrCl > 65mL/min, creatinine above 2.5mg/dL, chronic SAH or DM2 with glomerulosclerosis between 15-50%. Three-year survival was 79.8%.
Ekser et al considered donor age, and clinical and histopathological findings. The three-year graft survival was 90.9%.
Snanoujd et al considered CrCl < 30mL/min discarding the organ, above 60mL/min performing SKT, and between these values DKT with graft survival in two years of 90%.
United Kingdom suggested that donors over 70 years old with at least one risk factor: SAH, AMI, DM 2, cardiovascular death, serum creatinine above 2, and presence of a renal anatomic anomaly. In addition, prolonged warm ischemia time and small kidneys must be considered.
In pediatric patients, there is a great anatomical challenge (high risk of thrombosis and vascular lesions) as well as the match between age, weight, and immunological context.
To minimize low renal mass, it is preferable to make these organs available to patients with low immunological risk, younger than 60 years, and with a BMI less than 30. Weight and height should be considered.
The surgical technique is a challenge, as one kidney on each side increases the surgical time and the trauma area, compromising the patient’s warm ischemia time and perioperative recovery. Even when establishing unilateral deployment, several techniques have been established to minimize the risks discussed above.
Studies by Lee, UNOS, D Arcy, and Snanoujd reiterated the groups with the greatest advantage for DKT, with good results in three years. Tanriover places DKT with OR 0.76 when compared to SKT in ECD patients. In fact, DKT decreased the discard rate of organs that would be submitted to SKT by three times.
Complications are related to greater surgical trauma, greater risk of thrombosis, vascular injuries, leakage of anastomoses, increased warm ischemia time, ureteral stenosis, urinary fistula, recurrent urinary tract infection, and the need for an intensive care unit. But the positive impact of performing DKT in patients with ECD or suboptimal renal function is undeniable.
Dual Kidney Transplant. Introduction.
One of the ways to increase donor pool is to increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) , and using donors older than 60 years or those who are older than 50 with a history of hypertension, had cause of death due to cerebrovascular events, or have serum creatinine level at retrieval of more than 1.97 mg/dL which they called ECD and also DCD but using kidney with marginal criteria has high risk of mal-functioning graft due to decreased nephron mass therefore dual kidney transplantation has been adopted but still there are some limitations as surgical and vascular complications and poor graft outcome.
which kidney is suitable for dual transplant?
No global consensus regarding criteria for DKT but each center has his own experience but UNOS database published on 2008,about 525 DKT from 2000 to 2005, they were considering DKT if two criteria fulfilled from these criteria :
1-age greater than 60 years.
2-Creatinine clearance greater than 65 mL/min.
3-Rising serum creatinine greater than 2.5 mg/dL at retrieval.
4-Chronic hypertension or type 2 diabetes mellitus.
5-glomerulosclerosis on biopsy between 15% and 50%.
We can avoid biopsy based decision depending on e GFR ,donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
United Kingdom Kidney Advisory Group: kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
Sheffield center:
uses this approach. Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus. who is a suitable recipient?
Better thing to match the recipient regarding age and size as older recipient can tolerate nephron mass and expected life time and better to be low immunological risk as recipients without previous transplant and panel reactive antibody titer < 50% to avoid over immunosuppression and attacks of rejections.
Sheffield center: prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2. Surgical technique.
Transplanting 1 kidney to each side was the first approach and had more tissue dissection and a longer operative time.
A midline extra peritoneal approach characterized by a shorter operative time and dissection and fewer hernia complications.
Unilateral placement of both kidneys reduced trauma from the surgical procedure and operative time. Moreover, the contralateral side remained untouched for possible future transplant which is the preferred technique in most centers .
To avoid vascular complications in pediatric DKT, En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk. Graft and patient survival.
Studies shown that recipients of DKT had better graft function than both control groups (recipients of SKT from donors > 60 y or from donors < 50 y but the follow up period was short.
Lee and associates reported similar patient and graft survival at 1 year and 2 years between DKT and SKT.
UNOS database shown that recipients of DKTs from ECDs had similar death-censored graft survival and also showed that 77% of EBKs were from donors < 5 years old, graft survival at 1, 3, and 5 years was superior (85%, 76%, 71%) versus SKT.
The Newcastle team reported similar eGFR results at 3 and 12 months post-transplant in a comparison of DKT with donations after cardiac death versus SKT.
Proteinuria was slightly increased during follow-up. Of note, the pediatric kidneys grew to approach adult kidney size in the first months due to increasing nephron mass and risk of sclerosis. Complications.
Local wound dehiscence which is now low with new techniques.
Early renal graft thrombosis & vascular thrombosis.
Urinary tract complications(fistulae, stenosis).
Myocardial infarctions when compared to SKT candidates due to longer operative procedure and anesthetic time. Conclusions.
Dual kidney transplant allocation criteria still need more randomized control studies to give us consensus in selection the donors and recipients because it considered a great source of donation from marginal kidneys and has same graft and patient survival as SKT, Ipsilateral placement of both grafts is widely accepted and performed approach with less surgical and vascular complications.
To increase the number of donor pool, DKT from marginal kidneys are used (ECD and DCD) to maximize nephron mass
Many centers discard DKT as there in no clear guidelines, lack of experience and higher risk of surgical complications
Which kidney is suitable for dual transplant?
There are no guidelines to determine which kidney is suitable for DKT as there is no experience
Donor age, clinical risk factors and histology may be the most important factors
Donors with eGFR > 60 mL/min is considered for SKT, discard when eGFR < 30 mL/min, and eGFR between these results is for DKT
For biopsy score, 0-3 score or SKT, 4-6 for DKT, and discard if score is 7-12
The United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of HTN, MI, type 2 DM, CVA as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (RAS,APKD, small kidneys)
Histology is according to Remuzzi score of pretransplant biobsy (Glomerular global Sclerosis, tubular Atrophy, interstitial Fibrosis, and arterial and arteriolar narrowing)
Who is a suitable recipient?
The best candidate for DKT is not known
Suitable may be may be older recipients (older for older), recipient size and lower immunologic risk
Surgical technique
Unilateral placement of both kidneys through midline infraumbilical incision (extraperitoneal approach). This leads to shorter operative time and the graft survival at 1 year is similar to the bilateral technique
Outcomes and surgical complications were similar to SKT
Graft and patient survival
Patient and graft survival are comparable to SKT in most studies
In one study (Lee and associates), patient and graft survival at 1 year were (98% and 89% in DKT vs 97% and 90% in SKT) and 2 years (86% and 77% in DKT vs 95% and 86% in SKT).
Factors affect graft function are donor factors, donation circumstances, cold ischemia time, and perioperative events
En block kidney transplant was associated with slightly increased risk of graft loss when compared to SKTs
Complications
Complications are usually higher due to technical difficulties (long surgery time)
The most worrying complication is the early graft thrombosis
Other complications are wound dehiscence, urinary tract fistulas, higher risk of postoperative MI, and higher postoperative admission to ICU
According to a larger study, no difference in complications between ipsilateral DKT and SKT
EBK has a higher complication rate when compared to SKT
limitations of the study: level 5 study and limited cases in many centers
Conclusions
The outcomes of ipsilateral DKT are comparable to SKT
Despite the higher surgical complications, the outcome of an en block technique used in pediatric kidneys is the same
Further studies are required to determine which kidney is more suitable as DKT or SKT and to standardize criteria for DKT kidney allocation
This is a narrative review with level of evidence V
Renal transplantation outcomes are better than long term dialysis outcomes…A lot of patients are on waiting list for transplantation because of organ donor shortage….Dual Kidney transplantation is way to accept marginal kidneys and increase nephron mass for donation especially with ECD and DCD…
IT was there 1966, Johnson and his team did the first dual kidney transplant from donor above 60 years with history of HTN,DM and creatinine clearance between 40-80ml/min/m2…
There are no guidelines for dual kidney transplants. All the available evidence are usually center based and experience based…
The most widely used criteria for donors of dual kidney transplant are; Donor age>60 years, Donor’s creatinine clearance between 30-60ml/min/m2, donor terminal creatinine>1.97, donors with diabetes, hypertension non heart beating donors, proteinuria and renal anatomical abnormality…It is customary to do a renal biopsy for donors if there is ECD or kidney with abnormalities….If the donors pre transplant kidney biopsy shows less than 50% GS we can accept…If the remuzzi score is between 7 to 12 we should discard the kidney….
It is important to select the recipient that it should be age matches with the donors, they should be of less immunological risk and minimal co morbidities with low BMI….
.
Surgical techniques: There are bilateral Gibson incision to place both the kidneys but this is a longer procedure and required longer anesthesia….The midline infra umbilical incision is used as it is associated with less dissection and shorter duration…Unilateral placement of both the kidneys are preferred where right kidney is above the left kidney..Right renal arery is anastamosed with right CIA…right renal artery is anastamosed to IVC.. The left renal vessels are anastomosed with the recipients external iliac vessels…
Pediatric En block kidneys are also taken up and there is a higher chance of graft thrombosis….
The rates of DGF in DKT is similar to single kidney transplant with standared criteria donor…The overall patient survival is similar in dual kidney and single kidney transplant …GRaft survvial is similar in Dual kidney transplant and single kidney transplant….
Dual kidney transplant is used mainly for marginal kidneys like in ECD ( old age ,low GFR with high serum creatinine so by this method you will increase the nephron mass and the result was comparable with the single kidney transplant
Dual kidney transplant may increase the functional nephrons. Kidneys being rejected for a single kidney transplant by other units were accepted for dual kidney transplantation
Donors were considered for DKT if any 2 of the following criteria present:
1. age greater than 60 years
2. creatinine clearance greater than 65 mL/min,
3. rising serum creatinine greater than 2.5 mg/dL at retrieval,
4. chronic hypertension or type 2 diabetes mellitus,
5. glomerulosclerosis on biopsy between 15% and 50%
Donors older than 65 years old with at least 1 of the following risk factors were considered:
Best candidate for DKTs:
Surgical technique
Graft and patient survival
Challenges:
In Nutshell:
Introduction:
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
Which kidney is suitable for dual transplant?
In a review of UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%. Three-year graft survival was 79.8%.
United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present:
history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
Kidneys with prolonged warm ischemia time, small kidneys, e GFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus.
Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
Kidneys were used for SKT if pressure flow index was 0.4 mL/min per 100 g/mm Hg and glutathione transferase was less than 100 IU/L/100 grams renal mass.
If pressure flow index was less than 0.4, kidneys were discarded. Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (e.g., comorbidities or cold ischemia).
Who is a suitable recipient?
Most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
Most authors have suggested DKTs to recipients with lower immune – logic risk (i.e., recipients without previous transplant and panel reactive antibody titer < 50%)
In general, DKT is offered to patients 60 years or older.
DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2.
Surgical technique:
Because most recipients are 55 years or older, reduction of total anesthetic, a shorter operative time, and less vascular anastomoses are desirable.
Unilateral placement of both kidneys:
The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava. Clamps were released, allowing perfusion of transplanted kidney before both the external iliac vein and external iliac artery were clamped distally to allow the anastomosis of left kidney vascular pedicle to external iliac vessels.
A modification was described in Ekser and associates in a report of 29 unilateral extra peritoneal DKTs.
Pediatric kidneys have higher risk of surgical complications, especially vascular as a result of small vessel size. En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
Graft and patient survival:
Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%. During the same follow-up, recipients of kidneys from standard criteria donors had better survival of 80%.
Complications
Local wound dehiscent.
Renal graft thrombosis.
Urinary tract fistulas.
Introduction
During the past decades, there have been major improvements in kidney transplant. Better peri operative care and immunosuppressive agents have improved patient outcomes. Renal transplant is the treatment of choice for patients with end-stage renal disease. In the United States, patients waiting for kidney transplant now number 50000 with an annual death rate of 6.3%.1 To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
which kidney is suitable for dual transplant? Dual kidney transplant is a waste of resources if a single kidney will keep the recipient dialysis independent. Equally, having a DKT with insufficient function is extremely unwelcomed. Thus, the decision of which kidney is suitable for dual transplant is crucial. There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers. In addition, the variations in practice and protocols between different surgeons and centers have led to differences in kidney selection criteria.
who is a suitable recipient? Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size. Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested. One reason is that the limited functioning nephron mass would be enough for an elderly recipient with limited metabolic demands and the elderly would not require graft survival of greater than 20 years based on their expected lifespan.
Surgical technique Johnson and associates6 described the first DKT; the original technique included bilateral Gibson incision and transplanting 1 kidney to each side. This method required more tissue dissection and a longer operative time. Because most recipients are 55 years or older, reduction of total anesthetic, a shorter operative time, and less vascular anastomoses are desirable.
Graft and patient survival The earliest report of DKT documented 100% graft and patient survival in 9 DKTs. Although the mean follow-up was short (6 months; range, 2-14 months), recipients of DKT had better graft function than both control groups (recipients of SKT from donors > 60 y or from donors < 50 y).
Complications
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality. Lee and associates14 reported a local wound dehiscence rate of 5% in their series of 41 DKTs. Their approach was midline extraperitoneal bilateral placement of both kidneys. Early renal graft thrombosis is a cause of concern in DKT. In a report, 5 kidneys (12%) of 42 transplanted kidneys showed thrombosis. One patient had bilateral thrombosis, and 3 recipients had single kidney thrombosis but with renal function preserved by the other kidney.
Conclusions
Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys. Ipsilateral placement of both grafts is widely accepted and performed. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs. Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate. The main question is which kidney is more suitable as DKT or SKT. Selection criteria for DKTs are still variable and center dependent. There is reluctance of many centers to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide. More research should help to develop standardized criteria for DKT kidney allocation.
Dual Kidney Transplant
The concept of dual kidney transplant orginated from the fact that single marginal kidney provide suboptimal number of functional nephrons while receiving 2 marginal kidneys would provide more nephrons.
Criteria for selection of the kidneys for dual transplant:
There is consensus due to the fact that few centers adopt this and furthermore they use different protocols. criteria used in the early studies were age more than 60 years , long history of hypertension or diabetes with cold ischemia time less than 30 hours, creatinine clearance levels between 80 and 40 mL/min , kidneys that showed less than 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy and rejected kidneys from a single kidney transplant.
Remuzzi scoring system is based on pretransplant biopsy findings and kidneys with a score was between 4 and 6 are used for dual kidney transplant.
UNOS data used kidneys for dual transplant if any 2 of the following are present: age more than 60 years, creatinine clearance more than 65 mL/min, rising serum creatinine more than 2.5 mg/dL at retrieval, chronic HTN or type 2 DM, and glomerulosclerosis on biopsy between 15% and 50%.
sclerosis was > 20% in donated kidneys was associated with higher delayed graft function (80%) .
donor eFGR used instead of biopsy-based decisions. the eGFR between 60 mL/min and 30 mL/min were used for DKT. Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. eGFR between 60 mL/min and 30 mL/min.
United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
The auther’s center also uses the last approach. Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus. Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
Newcastle experience used kidney donations for DKT. Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (eg, comorbidities or cold ischemia).
Recipient selection:
matching recipients with donors by age and size.
recipients with lower immuno logic risk
DKT is offered to patients 60 years or older.
The auther criteria are low immunological risk, less than 60 years old, have minimal comorbidities and body mass index < 30 kg/m2.
Surgical technique
bilateral Gibson incision and transplanting 1 kidney to each side.
A midline extraperitoneal approach was described to minimize dissection and operative time.
Because the left iliac vein is in a deeper anatomic position, the left kidney with its longer renal vein was placed on the left side. Drains were placed bilaterally.
single midline incision advantages are : a shorter operative time and dissection , fewer hernia complications , a potential wound infection would be far away from the graft, can be converted easily to an intraperitoneal approach,
The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava. Clamps were released, allowing perfusion of transplanted kidney before both the external iliac vein and external iliac artery were clamped distally to allow the anastomosis of left kidney vascular pedicle to external iliac vessels. With this method, both ureters were spatulated and joined to each other. The conjoint ureters were anastomosed to the bladder with ureteric double J stent. This technique reduced trauma from the surgical procedure and operative time. Moreover, the contralateral side remained untouched for possible future transplant.
A modification was right kidney was placed superiorly, but the renal vein was extended using the donor’s inferior vena cava patch. It was anastomosed to the external iliac vein instead of the inferior vena cava. The group also anastomosed the transplant ureters through 2 separate extravesical ureteroneocystostomies on ureteric stents. The upper kidney ureter was placed lateral to the lower kidney ureter. Less dissection as the inferior vena cava is not used for anastomosis is an advantage.
Auther center extend the short right renal vein using the donor inferior vena cava anastomosed to the recipient’s inferior vena cava and use the common iliac artery as an inflow artery .
Graft and patient survival
The quality of DKT function is as important as how long it will keep functioning since the aim is to keep the patient dialysis independent for as long as possible. Many factors affect graft function, including donor factors, donation circumstances, cold ischemia time, and perioperative events.
Complications
technical difficulties, with longer operative time and lower kidney quality. a local wound dehiscence Early renal graft thrombosis Urinary tract complications especially urinary tract fistulas ureteric stenosis
Postoperatively, recipients of DKT have a higher risk of developing myocardial infarctions ,Higher postoperative admission rates to an intensive care unit
“wandering kidney,” the upper graft wandering to lay posterior to the lower graft.
The practice of DKT into a recipient has been implemented to augment nephron mass in marginal single kidneys, ECD, donors due to cardiac death.
Usually the DKT is thought of if donors age >60years, Cr cLl >65ml/min/m2, serum Cr >2.5mg/dl at the time of retrieval, HTN , DM with end organ damage, or biopsy showing glomerulosclerosis is 15-50%.
The suitable candidates are those having age 60 years or more and minimal immunological risk.
The dual kidney transplant increased the pool of potential organs for donation through increasing use of marginal kidneys.
The concept of DKT in a recipient has been adapted to increase nephron mass in marginal single kidneys, ECD, and donors with cardiac death.
Usually, the DKT is considered if donors age > 60 years, CrCl >65ml/minutes/m2, s.Cr >2.5mg/dl at the time of retrieval, hypertension, DM with end-organ damage, on biopsy the glomerulosclerosis is 15-50%.
The suitable candidates are those with aged 60 years or more and minimal immunological risk.
In a sense, the dual kidney transplant has increased the pool of potential organs by increasing the use of marginal kidneys.
Conclusions
· DKT increased the pool of donation by using marginal kidneys
· DKTs outcome is comparable to SKTs
· which kidney is more suitable as DKT or SKT is still questionable
With the increased use of organs with extended criteria (marginal kidney), there is an increase in organ transplants with a suboptimal number of functioning nephrons, bringing the risk of recipients not becoming independent of hemodialysis. And this risk becomes even greater when we remember that episodes of acute rejection, drug toxicity (particularly of calcineurin inhibitors), and the effect of recipient comorbidities on the transplanted kidney will also adversely affect these limited functional nephrons.
This need to increase the viable “mass of nephrons” gave rise to the idea of performing a transplant of two marginal organs from the same donor – double kidney transplantation, which in animal models has already been shown to effectively prevent the progressive deterioration of kidney function compared to controls of single transplant.
However, not everything is benefits. With the use of Double Transplantation (DKT) there is an increased risk of surgical complications due to the longer surgical procedure and the double risk associated with double vascular and ureteral anastomoses (increased early renal thrombosis, increased urinary tract fistulas requiring surgical repair, dehiscence of surgical wounds, among others), among other events that should be considered:
– which organs are suitable for DKT? So that it is not wasteful for 2 individual transplants, or even an insufficient double;
– which receiver is suitable for DKT ? Older patients would have a lower metabolic need for marginal kidneys and would use less immunosuppressants with a risk of kidney damage;
Despite these points, double kidney transplantation has increased the pool of potential organs by increasing the use of marginal kidneys, with graft and patient survival outcomes, complications, and quality of kidney function provided by double transplants being comparable to single kidney transplants. Therefore, the adoption of DKT by more centers depends only on the adoption of clearer criteria for organ allocation.
The concept of DKT into a recipient has been adapted to increase nephron mass in marginal single kidneys, ECD, donors with cardiac death.
Usually the DKT is considered if donors age >60years, CrCl >65ml/minutes/m2, s.Cr >2.5mg/dl at the time of retrieval, hypertension, DM with end organ damage, on biopsy the the glomerulosclerosis is 15-50%.
The suitable candidates are those with age 60 years or more and minimal immunological risk.
In a sense the dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys.
INTRODUCTION
· The transplant of a single marginal kidney may result in a suboptimal number of functional nephrons
· Transplanting 2 marginal kidneys to the same recipient, may increase the functional nephrons
· Kidneys being rejected for a single kidney transplant by other units were accepted for dual kidney transplantation
· Donors were considered for DKT if any 2 of the following criteria present:
1. age greater than 60 years
2. creatinine clearance greater than 65 mL/min,
3. rising serum creatinine greater than 2.5 mg/dL at retrieval,
4. chronic hypertension or type 2 diabetes mellitus,
5. glomerulosclerosis on biopsy between 15% and 50%
· Donors older than 65 years old with at least 1 of the following risk factors were considered: HTN, type 2 DM, atherosclerotic disease, or death from a cardiovascular event
· To select the best candidate for DKTs, it was suggested to match recipients with donors by age and size, e.g., matching an older donor with an older recipient
· To reduce possible injury to limited nephron mass, most authors have suggested DKTs to recipients with lower immunologic risk
· Younger candidates can more easily recover from the longer operative time necessary for DKTs
Surgical technique
· The first DKT was described by Johnson and associates; the original technique included bilateral Gibson incision and transplanting 1 kidney to each side. This procedure needs more tissue dissection and a longer operative time
· Haider and associates described midline infraumbilical incision in 2007, with blunt dissection of extraperitoneal space bilaterally to expose iliac vessels. Midline incision has a shorter operative time and dissection and fewer hernia complications
· Unilateral placement of both kidneys was described by Mason and Hefty in 1998.
– The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava
– left kidney vascular pedicle anastomosed to external iliac vessels, after de-clamping of the common iliac artery and renal vein, and clamping the external iliac vessels distally
· Ekser and associates modified the unilateral extraperitoneal DKTs:
1. The right kidney was placed superiorly, but the renal vein was extended and anastomosed to the external iliac vein instead of the inferior vena cava
2. the transplant ureters were anastomosed through 2 separate extravesical ureteroneocystostomies on ureteric stents
3. This technique has shorter operative time and length of hospital stay and a lower delayed graft function rate versus bilateral placement of DKT done by same team
· En block kidney transplant using pediatric donor aorta and the inferior vena cava used to reduce vascular complications of pediatric kidneys.
Graft and patient survival
· The earliest report of DKT documented 100% graft and patient survival in 9 DKTs
· Lee and associates suggested an older donor for older recipient strategy
· The 2007 review of the UNOS database found that recipients of DKTs from ECDs had similar death-censored graft survival, but during follow up recipients of kidneys from standard criteria donors had better survival of 80%
· Spanish report that compared survival of DKT recipients with SKT recipients of SKT found that there were no significant differences in patient or graft survival at 1 year
· Pediatric kidneys transplanted into adults as EBK have shown encouraging results
· The 2008 report from the UNOS database, found that incidence of DGF in DKT was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors
· En block kidney transplant was associated with slightly increased risk of graft loss when compared to SKTs
Complications
· with DKT are higher due to technical difficulties, with longer operative time and lower kidney quality
· Urinary tract complications are slightly higher, mainly urinary tract fistulas that may need surgery
· vascular thrombosis in the DKT group was higher
· Ekser and associates found that 2% renal vein thrombosis occured in both the bilateral and ipsilateral DKT groups
· Hobart and associates reported a higher EBK complication rate than SKT mostly due to smaller vessels
Conclusions
· DKT increased the pool of donation by using marginal kidneys
· DKTs outcome is comparable to SKTs
· which kidney is more suitable as DKT or SKT is still questionable
It is considering if SKT make patient dialysis I dependent
by increasing the pool of potential organs by increasing use of marginal
kidneys.
According to clinical practice guidelines
Pretransplant Biopsy Protocol
Glomerular Global Sclerosis: Based on 3 sections (First, Middle and Last if
available), the number of globally sclerosed glomeruli expressed as
percentage
0 None globally sclerosed
1 < 20% global glomerulosclerosis
2 20% – 50% global glomerulosclerosis
3 > 50% global glomerulosclerosis
Tubular Atrophy
0 Absent
1 < 20% tubuli affected
2 20% – 50% tubuli affected
3 > 50% tubuli affected
Interstitial Fibrosis
0 Absent
1 < 20% of renal tissue replaced by fibrous connective tissue
2 20% – 50% renal tissue replaced by fibrous connective tissue
3 > 50% of renal tissue replaced by fibrous connective tissue
Arterial and arteriolar narrowing: For the vascular lesions, if the changes are
focal, the most severe lesion present gives the final grade
0 Absent
1 Increased wall thickness but to a degree that is less than the
diameter of the lumen
2 Wall thickness that is equal or slightly greater to the diameter of the
lumen
3 Wall thickness that far exceeds the diameter of the lumen with
extreme luminal narrowing or occlusion
Only biopsies with ≥ 25 glomerules considered for evaluation. Kidneys with
evidence of acute tubular necrosis are not considered for DKT
Introduction
*Renal transplant is the treatment of choice for patients with end-stage renal disease.
*The transplant of a single marginal kidney (from
ECDs, donors with cardiac death, and pediatric
donors) may result in a suboptimal number of
functional nephrons to allow recipients to become
dialysis independent.
*The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.
which kidney is suitable for dual transplant?
Donors were considered for DKT if any
2 of the following criteria present:
-age greater than 60 years
-creatinine clearance greater than 65 mL/min,
-rising serum creatinine greater than 2.5 mg/dL at
retrieval
– chronic hypertension or type 2 diabetesmellitus,
– glomerulosclerosis on biopsy between 15% and 50%
who is a suitable recipient?
-patients 60 years or older.
-low immunological risk
– who are less than 60 years old, and who have minimal comorbidities
-body mass index < 30 kg/m2.
Graft and patient survival
Many factors affect graft function, including
donor factors, donation circumstances, cold ischemia
time, and perioperative events.
In the initial reports of DKT, delayed graft function was 11%. In the same study, delayed graft function reached 50% in SKT from older donors (> 60 y) and 20% in SKT from
younger donors (< 50 y).
Complications
*Complications with DKT are perceived to be higher
due to technical difficulties, with longer operative
time and lower kidney quality.
*Urinary tract complications
*vascular thrombosis
Conclusions
-Dual kidney transplant has increased the pool of
potential organs by increasing use of marginal kidneys.
-Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
-Selection criteria for DKTs are still variable and center dependent.
This a narrative review study with level V evidence.
Renal transplantation outcomes are better than long term dialysis outcomes. A lot of patients are on the waiting list for transplantation because of shortage of donors. Dual kidney transplantation (DKT) is a way to accept marginal kidneys and increase nephron mass for donation especially with ECD after DCD.
In 1996, Johson and his team did the first adult DKT when they transplanted kidneys from donors above 60-year-old with history of HTN, DM and Creatinine clearance between 40-80 ml/min/m2, CIT below 30 hours with GS less than 40% without severe IF or arteriosclerosis. 6 months patient and graft survival were 100%.
There are no available guidelines for allocation of DKT, it is usually center based.
Most widely used criteria for Donors of DKT:
1- Donor’s age>60
2- Donor’s Creatinine clearance between 30-60 ml/min/m2.
3- Donor’s terminal creatinine> 1.97 mg/dl.
4- Donor’s medical background: DM, HTN, non-heart beating donors, proteinuria below 3 gm/day or renal anatomical abnormalities.
5- Donor’s pre-transplant kidney biopsy: GS<50%, discard kidneys with Remuzzi score 7-12.
Most widely used criteria for Recipients of DKT:
1- Age matched recipient with the donor.
2- Low immunological risk.
3- Minimal co-morbidities, low BMI.
Surgical Techniques:
1- Bilateral Gibson incision (longer procedure and longer anesthesia).
2- Mid-line infra-umbilical incision (less dissection, shorter duration, less incidence of hernia).
3- preferred one is unilateral placement of both kidneys where right kidney is above left kidney and the right renal artery is anastomosed with the recipient CIA, right renal vein is anastomosed with the IVC. The left renal vessels are anastomosed with the recipient external iliac vessels.
4- In pediatric donors, the technique is En-block DKT which carries a higher risk of vascular complications up to graft thrombosis. The age of pediatric donors is usually between 2-5 years.
Outcomes of DKT:
1- Rate of DGF in DKT is similar to SKT with SCD.
2- Rate of DGF in DKT is lower than SKT with ECD.
3- Patients survival is similar in DKT to SKT.
4- Graft survival is similar in DKT to SKT.
5- DKT with ECD has similar death censored graft survival.
6- En-block DKT has better graft survival at 1,3 and 5 years with similar rates of DGF.
7- DKT carries higher risk of surgical complications compared to SKT.
8- Longer stay in ITU.
Limitations of the study:
1- Retrospective data.
2- The donors were not matched.
3- No trial to compare DKT vs SKT.
Summary of Dual Kidney TransplantUse the kidney from extended criteria a donors increase donor pool and organ shortage especially for whom on long time wating list .
Dual renal transplant into recipient aim to increase the nephron mass.
DKT has ahigh risk of surgical complication included vascular and ureteric anastomoses.
Many centres lack experience with DKT .
Absence of guidelines and allocation policies.
Selection criteria for DKT
First DKT recipient Jonson used kidney from donors more than 60 years old or long history of HTN or DM with cold ischemia less than 30 hours or creatinine clearance between 40 to 60 ml/min and less than 40% glommularscleosis without interatrial fibrosis or arteriosclerosis on biopsy.
Remuzzi used scoring system based on pretransplant biopsy for selection of a kidney for DKT .
Brain death donor more than 60 years old who were DM or donor with presence of proteinuria of less than 3 gm/24hours were considered.
Both kidney were biopsied and less 25 glommuleri were excluded.
4- 6 score so DKT can be carry on ,
Limitation of kidney biopsy :
Can be taken from kidney surface and be misleading which will overestimate glommuloscleosis.
Risk od bleeding and AVF as complication of kidney biopsy .
Using eGFR as criteria to select donor(sues Cockcroft and Gault):
eGFR more than 60 ml/min for SKT.
eGFR less than 30 ml/min kidney were discarded .
eGFR in between for DKT.
Using hypothermic machine perfusion to decided kidney donors:
Depend on pressure flow index which is enzyme marker of ischemic injury .
Pressure of flow index was 0.4ml/min per 100gmmHg and glutathione transferee less than 100iu /L 100gm renal mass.
If less than 0.4 kidney were discarded.
DKT if :
Pressure flow index was satisfactory but GST was higher than cut off value for SKT or other risk factor such as cold ischemia or other comorbidities.
Suitable recipient for DKT
Recipient with low immunological risk or PRA less than 50%.
Recipient age less than 60 years old.
Recipient with BMI less than 30 gm kg/ml.
Larger study showed no difference in complication rates between ipsilateral DKT and SKT .
Conclusion
· DKT increased the pool of potential organs.
· Ipsilateral placement of both graft is accepted and performed.
· Result of graft and patient survival complication and quality of renal function by DKT are comparable to SKTs .
· Selection criteria for DKT is centre dependent.
· Many centre still not performing DKT as no clear guidelines and this decision transplant dependence.
During the past decades, dual kidney transplant has enabled greater use of marginal kidneys and reduced waiting time.
Kidney survival and function are encouraging and close to results with standard criteria single kidney transplant.
To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available versus with a single suboptimal organ or as many functioning nephrons versus with a single ideal kidney
Nephron mass as a determinant of chronic allograft failure has been experimentally tested in animals, with results showing that increasing the size of viable nephron mass by transplanting 2 kidneys to the same recipient effectively prevents progressive deterioration in renal function compared with single transplant controls.
In a review of UNOS practices by Gill and associates, between 2000 and 2005, DKTs from donors > 50 years old accounted for only 4% of transplants.
Moreover, 54% of the kidneys from donors > 65 years old in the United States and 12% in Europe are discarded.
These limitations clearly indicate the need to expand DKT practice.
which kidney is suitable for dual transplant?
There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers.
who is a suitable recipient?
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size. Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
To reduce possible injury to limited nephron mass, most authors have suggested DKTs to recipients with lower immunologic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%).
In general, DKT is offered to patients 60 years or older. Our group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2 .
>>>>>>>> The quality of DKT function is as important as how long it will keep functioning since the aim is to keep the patient dialysis independent for as long as possible. Many factors affect graft function, including donor factors, donation circumstances, cold ischemia time, and perioperative events. In the initial reports of DKT, delayed graft function was 11%. In the same study, delayed graft function reached 50% in SKT from older donors (> 60 y) and 20% in SKT from younger donors (< 50 y).
Complications Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality.
Early renal graft thrombosis is a cause of concern in DKT.
Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery
Conclusions
Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys. Ipsilateral placement of both grafts is widely accepted and performed. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate.
The main question is which kidney is more suitable as DKT or SKT. Selection criteria for DKTs are still variable and center dependent.
There is reluctance of many centers to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide.
More research should help to develop standardized criteria for DKT kidney allocation.
Summary of the article.
Introduction:
Over the years the use of immunosuppressive and peri-operative care has improved the outcome of a kidney transplant. However, there was still the need to improve the post-transplant outcome of the kidney. This is why the introduction of dual kidney transplantation was introduced. The reason is that kidney transplantation is still the best option for kidney failure. In other to continue to improve kidney outcomes more research is being conducted with a combination of the currently well-known ones to continue improving the renal outcomes. This is why the introduction of dual transplantation.
It was first introduced in the United States around 1996 by Johnson and associates. The transplantation of a single kidney from ECD, DCD, AND DBD may give a suboptimal renal function due to a reduction of renal mass and nephrons. So the introduction of dual renal transplantation was adopted and as such give the possibility increase renal mass and possibly better renal function and outcome. So the idea came when 2 kidneys can be given when they have marginal functions and as such will have better kidney function rather than giving only one suboptimal kidney.
So with such a trial transplanting 2 kidneys, to the same recipient may prevent the progression of kidney failure and improve renal function when it is compared to a single transplant. It must be noted that dual kidney transplantation may carry higher risks like surgical complications due to a longer procedure, and the possibility of thrombosis.
Who has the criteria for dual kidneys?
1) Donors that are older than 60 years old
2) Duration of baseline pathologies like HTN and DM and also the presence of cold ischemia
3) The creatinine clearance is about 40-80 ml/min
4) On biopsy may show arteriosclerosis, or a less than 40 % GS
5) The Remuzzi criteria about 4-6
The recipient may be someone who is older than 60 years old, has lower immunological risk, and has a BMI of less than 30 kg/m2 and minimal comorbidities.
There have been special surgical techniques that have been described like the midline extraperitoneal approach and the unilateral placement of both kidneys.
Conclusion:
The outcome of the graft survival and the patient outcome and complication is comparable to single kidney transplantation. However, it must be noted that there are complications to the procedure like renal graft thrombosis, and urinary fistula.
Dual kidney transplantation has improved the donor pool by increasing marginal kidneys.
The use of the pediatric block technique in adult recipients has been in an encouraging outcome.
The concept and use of dual kidneys have not been accepted in some centers due to a possible lack of knowledge and guidelines and as such more studies need to done and the creation of guidelines.
Introduction:
The transplant of a single marginal kidney (from ECDs, donors with cardiac death, and pediatric donors) may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent.
The concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available nephron mass. The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available.
Which kidney is suitable for dual transplant?
There is so far no global consensus as to which donor kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers.
In 1999, Remuzzi and associates 4 suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT. Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered. Kidneys with macroscopic major vascular abnormality or evidence of focal scarring (ie, chronic pyelonephritis) were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. Dual kidney transplants were performed if a priori score was between 4 and 6.
In a 2000 study by a Spanish group, kidneys from brain dead donors with normal serum creatinine levels were considered for DKT if donors older than 75 years old. In addition, donors between 60 and 74 years old with glomerulosclerosis of 15% to50% at biopsy also were included.
In a review of UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min,
rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%.
To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead. Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when
eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
who is a suitable recipient?
Because most DKTs involve donors at age extremes, matching an older donor with an older recipient is suggested.
Surgical technique:
The single midline incision has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision.
A modification was described in Ekser and associates in a report of 29 unilateral extraperitoneal DKT. The right kidney was placed superiorly, but the renal vein was extended using the donor’s inferior vena cava patch. It was anastomosed to the external iliac vein instead of the inferior vena cava. The group also anastomosed the transplant ureters through 2 separate extravesical ureteroneocystostomies on ureteric stents. The upper kidney ureter was placed lateral to the lower kidney ureter. Less dissection as the
inferior vena cava is not used for anastomosis is an advantage.
Conclusion:
Kidney survival and function are encouraging and close to results with standard criteria single kidney transplant.
This literature review of different DKT aspects, techniques, and results that address points for further research.
dual kidney transplant has enabled greater use of marginal kidneys and reduced waiting time.
transplant of a single marginal kidney
result in a suboptimal number of functional nephrons which will be fragile and easily affected by episodes of acute rejection, medication toxicity, and effect of the recipient’s comorbidities.
concept of transplanting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
Although no randomized prospective studies to compar results of DKT with single transplant, but some studies have reported acceptable results even with kidneys considered unacceptable by others.
It still uncommon in many centres due to lack of solid guidelines and relatively higher surgical complications.
▪︎which kidney is suitable for dual transplant?
the decision of which kidney is suitable for dual transplant is crucial.
There is no global consensus about it,
the variations in practice and protocols between different surgeons and centers have led to differences in kidney selection criteria.
a review of UNOS published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005.
Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%.
Three-year graft survival was 79.8%.
Pretransplant biopsy is important to evaluate donor kidneys as it was shown that Five-year survival was 80% when protocol biopsy showed no glomerulosclerosis and dropped to 35% when sclerosis was > 20% in donated kidneys,with higher incidence of DGF ( 80%) with sclerosis > 20%.
Biopsy may sometimes be misleading to avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead ,donors with eGFR 30-60 mL/min were considered for DKT.
▪︎who is a suitable recipient?
there is debate about the best candidate for DKTs.
matching an older donor with an older recipient is suggested.
To reduce possible injury to limited nephron mass, it was suggested DKTs to recipients with lower immuno-logic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%).
The study group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2 .
▪︎Graft and patient survival
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs. Although the mean follow-up was short (6 months; range, 2-14 months).
studies on older donor for older recipient strategy reported similar patient and graft survival at 1 year.
Few Studies that compared patient and graft survival for SKT and DKT found no difference.
reports on pediatric kidneys transplanted into adults as EBK have also shown encouraging results.
2003 reported results of 2160 recipients of EBK. The report showed that 77% of EBKs were from donors < 5 years old; however, graft survival at 1, 3, and 5 years was superior (85%, 76%, 71%) versus SKT (81%, 68%, 63%).
Two large analyses of the UNOS database have been published. The 2008 report documented 625 DKTs , despite a longer cold ischemia time in the DKT group versus that shown for groups who underwent SKT with ECD and standard criteria donor kidneys but delayed graft function incidence was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors.
▪︎complications
Complications of DKT are higher than SKT due to technical difficulties, with longer operative time and lower kidney quality.
-graft thrombosis and vascular thrombosis were reported in many cases of DKT.
-Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery.
– higher incidence of post operative MI and admission to icu .
▪︎Limitations of the study
-data is retrospective no control group .
– no match in donors age ,medical conditions, cause of death
-Small number of patients and short follow-up period in many of reported studies.
▪︎Conclusions
Dual kidney transplant increased the pool of potential organs by increasing use of marginal kidneys.
Ipsilateral placement of both grafts is widely accepted and performed.
Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
use of pediatric kidneys by an en block technique into adult recipients has resulted good resullts.
Selection criteria for DKTs are still variable and center dependent.
More research should help to develop standardized criteria for DKT kidney allocation.
This review is done by our prof; Ahmed Halawa
Summary of the article;
Introduction;
Kidney transplantation is the best treatment modality for ESKD, with improving transplantation, and increasing N0. of waiting list dialysis patient who is fit for transplantation, lead to an increase the need for kidneys to face this need, However, the use of marginal kidneys, ECD, DCD, donors, may help to meet this demand. And with the improvement of preparation o donated kidneys and measures used to keep kidneys of good quality, and gain successful graft function.
In considering such kidneys with low nephron mass, the dual kidney transplant practice had been improved and established, so the number of discarded kidneys had become less.
And this also can help the usage of the pediatric kidney in adult recipients to achieve a compatible nephron mass.
The 1st DKT was done in Us in 1996 by Johnson and associates.
DKT carries a potential risk of surgical complication, so it takes more time and hence requires a fit recipient.
UNOS practices by Gill and associates in the US between 2000 and 2005, only 4% of transplants were DKT.
Donor considered for KDT if any 2 of the following;
Three years of graft survival was 79.8%.
Moreover, 54% of kidneys from donors> 65 years old in the US and 12 % in Europe are discarded, and actually, these limitations rose the need of using a DKT.
Kidney’s criteria for DKT:
Rumuzzi and associates DKT criteria based on a pre-transplant biopsy;
Spanish group in a 2000 study; Kidneys from BDD with normal S.Cr are considered for DKT if;
Italian Study between 2003-2009;
eGFR donor > 60 ml/min considered for SKD.
Kidney discarded when eGFR < 30 ml/min.
Center of the publisher of this study use the following for DKTs;
DKTs; from donors with maastricht category 2,(15) donors, and category 3 (8) donors;
EBK;
Suitable recipients suggestions;
Surgical technique;
Unilateral DKTs;
Pediatric kidney transplant;
Graft and patient survival ;
With improved outcomes of kidney transplants in the face of increased need, the usage of organs from age extremes was suggested. The problem with pediatric donors is the low number of nephrons. The same is applicable for advanced age due to glomerular sclerosis. The renal biopsy (used to be wedge biopsy) exaggerates the number of sclerosed glomeruli because the sample includes a sample from the periphery (renal capsule) where sclerosis begins. this lead /may lead to the avoidance of kidneys unnecessarily. In 2003 UNOS implemented the use of kidneys from extended criteria donors. ECD included donors>60 years and those >50 with a history of HT, CVA or scr>1.97 mg/dl.
Dual kidney transplantation aims to increase the number of functional nephron mass. The first DKT into adults was performed in 1996, preceded 2 decades earlier by transplanting pediatric kidneys into adults. The lengths of operation of DKT discouraged many surgeons because of either lack of experience, lack of consensus guidelines and high probability of surgical complications either because of long duration or vascular complications.
Many trials and groups performed successful operations with encouraging results but the survival of kidneys was higher in the short term than the long term (2- 3 years or more).
To avoid misleading biopsy-based decisions, the eGFR in donor was used for estimation. maximal eGFR > 60 was considered for single kidney transplantation, while eGFR <30 was a reason for avoidance. eGFR between 30-60 was considered for DKT.
Donor selection is an issue, but most centres agree that matching donors’ age is better. Old for old.
Many surgical techniques were performed. First, it was done by bilateral Gibson incision and transplanting each kidney in opposite sides. Later in 2007, Haider and associates used midline incision with the advantage of shorter operation time. In 1998 Mason & Hefty introduced unilateral placement of both kidneys in 1998. The right kidney was placed superiorly with renal a. anastomosed into the common iliac artery and renal v into IVK. EKSER and associates modified this operation by anastomosing the right kidney vein into the external iliac vein instead of IVK using the donor’s IVC patch.
Monolateral placement of kidneys has the advantage of shorter operation time and stay at the hospital.
Introduction
Kidney transplantation is the treatment of choice for ESKD as it offers a mortality benefit over dialysis. However, the number of patients on the waiting list is increasing and the number of organs available for transplantation has reduced. To increase the number of transplants organs from DCDs donors are ECD are being utilized as well as pediatric donors. Transplantation of organs from marginal donors poses a challenge due to the lower number of functioning nephrons and increased risk of DGF and reduced graft survival. Dual kidney transplantation has been utilized to increase the nephron mass and prolong graft survival. This has been tested in animal studies that showed that by increasing the viable nephron mass by transplanting 2 kidneys to the recipient prolongs graft survival. The first adult DKT was performed in 1996 by Johnson and associates. DKT carries a higher risk of surgical complications due to the longer surgical procedure and dual ureteric and vascular anastomoses.
There are no criteria and guidelines as to which donor kidneys can undergo SKT and which ones undergo DKT. There are also no guidelines as to which surgical technique is the best for DKT. Therefore, not very many centers perform DKTs.
Which Kidney Is Suitable For DKT?
The transplant team will have to decide which kidneys can be used for SKT or DKT. If kidneys suitable for SKT are both transplanted in one recipient, it will be a waste of resources and one potential recipient will be on the waiting list for longer. If kidneys that are marginal and have a lower nephron mass undergo SKT, then they will have reduced graft survival.
In the first adult DKT the criteria used was donors older than 60 years, h/o DM and/or HTN and a long cold ischemia time of more than 30 hours. The terminal donor creatinine was between 40-80 mls/min/m2 and the kidneys had less than 40% glomerulosclerosis.
They reported 100% patient and graft survival at six months.
Remuzzi and associates have suggested a scoring system based on pre-transplant biopsy for selection of kidneys for DKT. Kidneys with macroscopic vascular abnormalities, focal scarring or where the biopsy core had less than 25 glomeruli were excluded. DKT was performed if the priori score was between 4 and 6 and they reported a 100% patient and graft survival at six months
In a Spanish study of DKT, they included kidneys form DBD donors who had a normal serum creatinine and were more than 75 years of age or between 60 and 74 years with glomerulosclerosis of between 15% and 50%. Graft survival was 95% in 21 recipients.
Histologic findings determine the rate of graft survival. Five year graft survival was 80% when protocol biopsy showed no glomerulosclerosis and reduced to 35% when glomerulosclerosis was more than 20%. However, on e of the major limitations of using histological criteria is that the biopsies are dependent on the person doing the biopsies. Most surgeon obtain elliptical biopsies from the surface of the kidney and that will give a falsely higher rate of glomerulosclerosis and will lead to DKT or discarding of kidneys.
The terminal donor creatinine and eGFR can be used to avoid biopsy based decisions. eGFR of more than 60 mls/min is considered for SKT and eGFR between 30 and 60 mls/min for DKT. Kidneys with eGFR of less than 30 mls/min were discarded. Snanoudj et al used this protocol and performed 81 DKTs with a 2 year graft survival 90%.
The UK kidney advisory group has suggested that kidneys from donors aged more than 70 years or older can be used for DKT if one or more of the clinical risk factors were present:
Newcastle criteria can also be used to determine if the kidneys should undergo DKT or SKT depending on the HMP characteristics including pressure flow index and perfusate glutathione transferase. If the pressure flow index was 0.4 and the GT was more than 100, then both kidneys would be transplanted in one recipient. If the perfusion pressure was less than 0.4, the kidneys would be discarded.
Who Is A Suitable Recipient?
Many authors suggest matching recipients by donor age and size. An older recipient is normally selected for DKT due to the reduced immune response they generate and limited metabolic demands of elderly recipients. Most authors have also suggested DKTs for recipients with lower immunological risks
Utilizing younger recipients for DKTs has an advantage due to longer operative time for DKTs which can result in prolonged recovery time in the elderly. In general DKT is offered to patients 60 years or older. At the authors center, the recipients given DKTs are younger than 60 years of age, have minimal comorbids and have a BMI less than 30.
Surgical Techniques
The first adult DKT was performed using bilateral Gibson incision and transplanting one kidney on each side. This method required more tissue dissection and a longer operative time. A midline extraperitoneal approach was described to minimize dissection and operative time. It has the advantage of a shorter operative time and dissection and fewer hernia complications compared to a bilateral Gibson incision.
Unilateral placement of both kidneys was described by Mason and Hefty in 1998. The right kidney was placed superiorly with the renal artery anastomosed into the common iliac artery and renal vein into the IVC. With this method, both ureters were spatulated and joined to each other. The conjoined ureters were anastomosed to the bladder with a ureteric double J stent
A modification was described by Esker and colleagues. The right kidney was placed superiorly, but the renal vein was extended using the donor’s IVC patch. It was anastomosed to the external iliac vein instead of the IVC. The group also anastomosed the transplant ureters through 2 separate extravesical ureteroneocytostomies. The upper kidney ureter was placed lateral to the lower kidney ureter.. This technique has shorter operative time and length of hospital stay and a lower DGF
Pediatric kidneys have a higher risk of surgical complications especially vascular due to the small vessel size. En bloc kidney transplant using donor aorta and IVC can theoretically reduce that risk. One of the main concerns of transplanting the kidneys en bloc is the risk of torsion of the whole bloc or one kidney at risk of thrombosis due to a longer vascular pedicle
Graft and Patient Survival
Earlier reports showed that the patient and graft survival was 100% although the mean follow up was for only six months
Using an older donor to older recipient strategy, Lee et al reported similar graft and patient survival outcomes compared to SKTs. However, the 2007 review of the UNOS database showed that the SKTs had better survival than DKTs
DKTs had lower rates of DGF when compared to SKTs from ECDs and similar rates when SKTs from SCDs
The PNF was also low at 1.8%
Complications
Complications are perceived to be higher with DKTs due to the technical challenges and the longer operative times with low quality kidneys. Midline extraperitoneal approach is associated with a dehiscence rate of 5%. Early renal graft thrombosis is also a concern in DKTs.
urinary tract complications have also been reported to be slightly higher especially urinary tract fistulas requiring surgery. In a French report, 11% of the recipients had ureteric stenosis and a similar rate urinary fistula.
Postoperatively, recipients of DKTs have a higher risk of developing MIs compared to SKT candidates.
Monolateral placement of both kidneys reduces the length of the surgical procedure and the length of the hospital stay. A large study showed no differences in complication rates between ipsilateral DKT and SKTs
En bloc kidney transplantation has a higher risk of complications compared to SKT. Thrombosis of the renal vein, artery or even the donors aorta was observed in the series reported by Hobart et al
One can also get a wandering kidney where one of the kidneys can move from its location.
Conclusion
DKT has increased the donor pool and has the potential of reducing waiting times. If carefully selected, DKTs have similar graft and patient survival as compared to SKTs. DKTs reduce the rates of DGF and PNF.
The surgical complications of DKT can be reduced by ipsilateral placement of the kidneys as this reduces surgical time and the length of hospital stay
Dual Kidney Transplant;
Introduction;
The transplant of a single marginal kidney may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent. Episodes of acute rejection, medication toxicity , and effect of the recipient’s comorbidities on the transplanted kidney will adversely affect these limited functional nephrons.
The concept of trans-planting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.”
Dual kidney transplant carries a potentially higher risk of surgical complications because of the;
1- longer surgical procedure .
2- fold risk associated with double vascular and ureteric anastomoses .
History ;
The first adult dual kidney transplant (DKT) was in the United States in 1996 .
Which kidney is suitable or dual transplant ;
Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus. Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
Selection criteria for DKTs are still variable and center dependent.
1-Biopsy based criteria;
Needle biopsy is usually avoided by surgeons because of risk of;
1- bleeding .
2- arterio- venous fistula formation.
3- there might be an element of individual interpretation variations in biopsy scoring, despite a structured scoring system.
A-In 1999, Remuzzi and associates suggested ascoring system based on pretransplant biopsy for selection of a kidney for DKT.
This scoring exclude Kidneys with ;
1- macroscopic major vascular abnormality .
2-evidence of focal scarring .
B- In a review of UNOS database published on 2008, five hundred twenty-five DKTs were performed from 2000 to 2005.
Donors were considered for DKT if glomerulosclerosis on biopsy between 15% and 50%.
2-eGFR based criteria;
To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead.
Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula;
1-donors with eGFR > 60 mL/min were considered for SKT.
2-Kidneys were discarded when eGFR was < 30 mL/min, and
3-eGFR between these results was an indicator for DKT.
Snanoudj and associates performed 81 DKTs using this protocol, with 2-year graft survival of 90%.
Who is a suitable recipient?
1-DKT is offered to patients 60 years or older.
2-Patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m.
Surgical technique;
Ipsilateral placement of both grafts is widely accepted and performed.
Graft and patient survival ;
Results of graft and patient survival, complications, and quality of renal function
provided by DKTs are comparable to SKTs
Complications ;
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality. Although there is a higher prevalence of vascular complications, mainly in the form of graft thrombosis, the overall complication rate with dual kidney transplant is comparable to single kidney transplant.
According to this article ,it will increase the chance of transplantation and will reduce the waiting list ,but still DKY have a lot of area of debate and it is mainly depending on the center and the nephrologist physician .
This article give us some information about the DKT and the complication associated with it.
IF we speak about kidney suitability for DKT it depend on different approach;
Most of the data available is suggested the following criteria for the recipient :
SUMMARY
Introduction
The increasing general public acceptance of kidney transplantation as the best form of renal replacement therapy is due increase in surgical skills and the availability of potent immunosuppressives which has greatly increased the recipient and graft survival. In order to increase the number of available organs for transplantation, the use kidneys from donors with extremes of age has been recommended. However, episodes of acute rejection, CNI toxicity, and recipient background comorbidity will ultimately affect the marginal functioning kidneys, hence the concept of dual kidney transplant has been suggested. The theory is that two marginal kidneys will contain more good nephrons than single marginal kidney. Nevertheless, the procedure involved carries a higher vascular and ureteric risk with long duration of surgery in mostly elderly patient.
Suitable kidney for DKT
It is unfortunate that there is no general consensus or agreement on the kidney to be used for DKT as most criteria are center specific and depend largely on the attending physicians. However, few authors have reported their various experiences
Suitable recipient for DKT
-many authors suggested the following
The surgical technique has been either bilateral Gibson or use of unilateral Gibson which is more accepted because of lesser surgery time and early recovery from surgery
Complications of DKT
Conclusion
The use of marginal kidney as DKT has helped to increase kidney donation pool and the outcome has been favorable compared with SKT in term of graft and patient survival even among pediatric where En block method has been used. However, lack of unified criteria for selection of kidneys for DKT is still a challenge that must be overcome.
Thankyou
Summary of the article
Dual Kidney Transplant
1996: The first adult dual kidney transplant (DKT) was in the USA, by Johnson and assoiates, with 100% patient and graft survival at 6 months;
a) older than 60 years.. and/or
b) long history of hypertension or diabetes.
c) cold ischemia time less than 30 hours.
They picked donors who had creatinine clearance levels between 80 and 40 mL/min and with kidneys that showed less than 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy.
Pre-transplant biopsy scoring system
Pre-transplant Biopsy Protocol
a) Glomerular Global Sclerosis: Based on 3 sections (First, Middle and Last if available), the number of globally sclerosed glomeruli expressed as percentage
0 None globally sclerosed
1 < 20% global glomerulosclerosis
2 20% – 50% global glomerulosclerosis
3 > 50% global glomerulosclerosis
b) Tubular Atrophy
0 Absent
1 < 20% tubuli affected
2 20% – 50% tubuli affected
3 > 50% tubuli affected
c) Interstitial Fibrosis
0 Absent
1 < 20% of renal tissue replaced by fibrous connective tissue
2 20% – 50% renal tissue replaced by fibrous connective tissue
2 > 50% of renal tissue replaced by fibrous connective tissue
d) Arterial and arteriolar narrowing: For the vascular lesions, if the changes are focal, the most severe lesion present gives the final grade
0 Absent
1 Increased wall thickness but to a degree that is less than the
diameter of the lumen.
2 Wall thickness that is equal or slightly greater to the diameter of the lumen.
3 Wall thickness that far exceeds the diameter of the lumen with extreme luminal narrowing or occlusion.
Only biopsies with ≥ 25 glomerules considered for evaluation. Kidneys with evidence of acute tubular necrosis are not considered for DKT
When to consider DKT:
1. According to a review of UNOS database (2000 – 2005), donors were considered for DKT if any 2 of the following criteria present:
a) Age greater than 60 years.
b) Creatinine clearance greater than 65 mL/min.
c) Rising serum creatinine greater than 2.5 mg/dL at retrieval.
d) Chronic hypertension or type 2 diabetes mellitus.
e) Glomerulosclerosis on biopsy between 15% and 50%.
2. Italian series of 100 unilateral DKTs performed between 2003 and 2009, allocation was based on:
a) donor age (mean donor age was 72 ± 5 years).
b) clinical and histologic findings.
3. To avoid biopsy-based decisions (Snanoudj and associates): the 2-year graft survival of this protocol is 90%.
a) The eGFR (according to CG formula) in the donor as a criterion was used instead.
1) donors with eGFR > 60 mL/min were considered for SKT.
2) Kidneys were discarded when eGFR was < 30 mL/min.
3) eGFR between 30 – 60 was an indicator for DKT.
b) Donors older than 65 years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event.
4. United Kingdom Kidney Advisory Group: DKT to be considered from donors who are age 70 years or older if 1 or more of the following clinical risk factors were present:
a) history of hypertension.
b) myocardial infarction.
c) type 2 diabetes mellitus.
d) cerebrovascular event as cause of death.
e) serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
5. Newcastle team experience (donors with Maastricht-II(15 donors) and Maastricht-III (8 donors) were reported):
a) All kidneys had hypothermic machine perfusion.
b) Pressure flow index, defined as flow per 100 grams renal mass divided by systolic blood pressure, and concentration of glutathione transferase, an enzyme marker of ischemic injury, in the perfusate were measured.
c) Kidneys were used for SKT if pressure flow index was 0.4 mL/min per 100 g/mm Hg and glutathione transferase was less than 100 IU/L/100 grams renal mass.
d) If pressure flow index was less than 0.4, kidneys were discarded.
e) Kidneys were considered for DKT if pressure flow index was satisfactory but GST was higher than cutoff value for SKT or if other risk factors were present (eg, comorbidities or cold ischemia).
f) The study showed delayed graft function rate of 81% but 3-month GFR of 46.2 ± 13.7 mL/min.
who is a suitable recipient for DKT ?
1. Matching recipients with donors by age and size(suggested by many authors).
2. DKT is offered to patients 60 years or older.
3. The study’s group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2.
4. Selection criteria for DKTs are still variable and center dependent.
Surgical technique
1. A midline extraperitoneal approach, through midline infraumbilical incision, blunt dissection of extraperitoneal space bilaterally to expose iliac vessels.
2. Bilateral Gibson incision.
3. Unilateral modified Gibson incision in En Block Kidney(EBK) transplant in pediatrics.
4. Unilateral placement of both kidneys was described by Mason and Hefty in 1998.
5. EBK with 2 adult kidneys performed in the same manner as with pediatric donors was also described. An Iranian center transplanted adult kidneys en block.
Outcome of DKT
1. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
2. The use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcome despite the higher surgical complication rate.
Complications of DKT
1. Complications with DKT are due to technical difficulties, with longer operative time and lower kidney quality;
a) Early renal graft thrombosis.
b) Urinary tract complications(ureteral complication or urine leak), especially urinary tract fistulas requiring surgery.
c) Higher risk of developing MI when compared to SKT candidates. Possibly due to longer operative procedure and anesthetic time in addition to older recipient’s age.
d) Wandering kidney is an interesting radiologic finding rather than a true complication.
2. A larger study also showed no differences in complication rates between ipsilateral DKT and SKT.
Excellent
– Here, this is a review of the current experience of dual kidney transplantation. The hypothesis is that transplanting 2 kidney donors in one recipient especially if ECDs with marginal kidney, will allow for available more nephron mass & improve the outcome. The first adult dual kidney transplant was in the United States in 1996 by Johnson and associates. still there is no strong evidence or consensus regarding DKT & the fear of increased surgical complications makes some centre reluctant especially with lack of experience.
– Combination of biopsy results with use of remuzzi score, donor criteria ( age , hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event & eGFR) & DCD will affect the decision of which kidney is suitable for DKT .
– Generally , DKT is offered to patients 60 years or older. offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2 is also preferable.
– Unilateral Placement of the 2 kidneys is the preferable technique with many benefits regarding decreasing time of the surgery, keeping the other side untouched for possible another transplant & the complications are comparable to that of SKT , the author here prefer to extend the short right renal vein using the donor inferior vena cava anastomosed to the recipient’s inferior vena cava & use the common iliac artery as an inflow artery .
– Two large analyses of the UNOS database have been published. The 2008 report documented 625 DKTs performed between January 2000 and December 2005. Despite a longer cold ischemia time in the DKT group versus that shown for groups who underwent SKT with ECD and standard criteria donor, delayed graft function incidence was lower than shown in recipients of SKT from ECD and similar to recipients of SKT from standard criteria donors
– Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality. Unilateral placement of both kidneys reduces length of the surgical procedure and hospital stay. Ekser and associates reported 2% renal vein thrombosis in both the bilateral and ipsilateral DKT groups (total of 58 DKTs), and no difference in the complication rates between both techniques. A larger study also showed no differences in complication rates between ipsilateral DKT and SKT. The ipsilateral placement reduced dissection time and made lymphocele risk similar to that for SKT procedures
Conclusion :
– Dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys.
– Unilateral placement of both grafts is widely accepted and performed. Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
– Selection criteria for DKTs are still variable and centre dependent. There is reluctance of many canters to perform DKTs because of lack of clear guidelines regarding allocation, which is usually left to the transplant clinicians to decide.
– More research should help to develop standardized criteria for DKT kidney allocation
Well done
Summary
This study is concerning dual kidney transplantation. Most centers perform unilateral kidney placement. Deciding to do dual kidney transplant is dependent on several factors. Due to the fact that dual kidney transplant is not performed regularly in many centers it is difficult to assess accurately which donor kidneys are best for this.
General characteristics of kidneys used for DKT include kidneys from brain dead donors, normal serum creatinine levels, above age of 60, glomerulosclerosis allowed unto 50% and BMI less than 30 kg/m2 with minimal co-morbidities. Graft survival can be good.
Older recipients are picked for DKT. This is because of the limited functioning nephron mass, limited metabolic demands, and the fact that expected lifespan would not be above 20 years. Recipients with lower immunological risk are better chosen for DKT such as those who did not undergo a previous transplant, and those with PRA titer less than 50%.
Operative method used for this is midline extraperitoneal approach.
DKT has good outcome with excellent creatinine levels and lower risk of acute rejection. This means that they can also be used in younger recipients and expected to have good outcome. In addition, an advantage is that younger recipients can recover quicker post transplant which is very helpful in the case of DKT.
Expected complications include longer operative time due to perceived technical difficulties and lower kidney quality. Early renal graft thrombosis can pose a serious complication. Urinary tract complications include urinary fistulas, urinary stenosis, vascular thrombosis. Post op complications in other areas include increased risk of myocardial infarction.
However, it is to be noted that mono lateral placement of both kidneys reduces the length of operative time as well as hospital stay. There is no difference in the incidence of complications in either approach. Ipsilateral placement is more widely accepted and done.
Use of pediatric kidneys by en block technique into adult recipients has good outcome for graft and patient, but the risk of complications is significantly higher.
Further research is needed to delineate which kidneys are to be selected for DKT, kidney allocation for which recipients, and standardized guidelines need to be developed so that DKT can become a more widely accepted and performed practice among transplant centers worldwide.
Thankyou
This article focus on indications and results of dull kidney donor in marginal kidney and extended kidney criteria to reduce waiting list for donation and improve quality of life in patients on dialysis for long time. Also due to super effectiveness of immunosuppressive therapy leading to increase incidence of survival graft.
Marginal kidney means older age more than 60 or less with history of diabetes and hypertension and serum creatinine level > 1.5. eGFR between 40 to 80ml/min. or evidence of cerebrovascular disease and causes of death are cardiac and circulatory arrest.
In 1999, Remuzzi groups suggest pretransplant biopsy for selection of a kidney for DKT.
Many centers not familiar with DKT. However survival rate with DKT 100% in first 6 months but risk of surgical procedure and complications of vascular anastomoses are doubled.
Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered. Kidneys with macroscopic major vascular abnormality or evidence of focal scarring (chronic pyelonephritis) were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. The study shows DKD graft survival was 100% at 6 months.
In a 2000 study by a Spanish group, kidneys from brain dead donors with normal serum creatinine levels were considered for DKT if donors older than 75 years old. Also donors between 60 and 74 years old with glomerulosclerosis between 15% to 50%.
In this study pre transplant biopsy done and Kidneys with less than 15% glomerulosclerosis were transplanted separately, and kidneys with greater than 50% glomerulosclerosis were discarded.
Consider DKT to recipients with lower immunologic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%.
Surgical technique mainly in right iliac fossa area, bilateral Gibson incision and transplanting one kidney to each side.
Ipsilateral placement of both grafts is widely accepted and performed and less wound infection.
The quality of DKT function is important since it will keep functioning for long time and keep the patient dialysis independent for as long as possible. Many factors affect graft function, including donor factors, donation circumstances, cold ischemia time, and perioperative events. Complications of DKT:
Thrombosis of renal graft
urinary tract infection
Well done
Introduction:
Renal transplant is the treatment of choice for patients with end-stage renal disease. To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
In late 2003, the United Network for Organ Sharing (UNOS) was implemented using kidneys from extended criteria donors (ECDs). Comprehensive criteria donors include donors older than 60 years or those older than 50 with a history of hypertension, who had a cause of death due to cerebrovascular events, or who have serum creatinine levels at retrieval of more than 1.97 mg/dL. In addition, donations after cardiac death have also been accepted worldwide as the source of organs despite being regarded as marginal due to their association with warm ischemic injury.
The concept of trans-planting both donor’s kidneys into one recipient as dual renal transplant has been adopted to increase available “nephron mass.”
The first adult dual kidney transplant (DKT) was in the United States in 1996 by Johnson and associates
which kidney is suitable for a dual transplant?
A dual kidney transplant is a waste of resources if a single kidney will keep the recipient dialysis independent.
In 1999, Remuzzi and associates suggested a scoring system based on pretransplant biopsy to select a kidney for DKT.
Dual kidney transplants were performed if the a priori score was between 4 and 6
Pediatric donors were first considered pediatric recipients. Because of increased surgical complications, inadequate nephron mass, relative sensitivity regarding rejection, and risk of hyperfiltration injury, pediatric SKT remains controversial
who is a suitable recipient?:
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size.
In general, DKT is offered to patients 60 years or older. Our group prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m
Surgical technique
Johnson and associates6 described the first DKT; the original technique included bilateral Gibson incision and transplanting 1 kidney to each side. This method required more tissue dissection and a longer operative time. Because most recipients are 55 years or older, a reduction of total anesthetic, a shorter operative time, and fewer vascular anastomoses are desirable.
The closing of the aorta below the origin of renal arteries, with the donor inferior vena cava closed above the source of renal veins and the lower end used for anastomosis into iliac vessels
Joining both renal arterial patches into one and using an inferior vena cava patch to elongate the right renal vein and then attaching both veins into a common ostium to allow single arterial and venous anastomosis was also described
Graft and patient survival:
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs
Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality than the other kidney. Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery (17%; P = .06), although no significant difference in overall surgical complications was shown.
Conclusions:
Dual kidney transplant has increased the pool of potential organs by increasing the use of marginal kidneys. As a result, the ipsilateral placement of both grafts is widely accepted.
What about the New Castle method of decision for DKT
Please provide a summary of this article
Dual kidney transplant is done when the donor is marginal and are placed in on recipient. It may improve the graft outcome.
Technique
Usually midline incision is given and both kidneys are placed extraperitoneally. Right kidney is placed over the left. the dual renal transplant is associated with higher complications as compare to single kidney transplant.
Anastomosis are done as below-
Right renal artery to Right Common illiac artery
Right renal vein to – IVC
Left renal artery to external illiac vein
Left renal vein to external illiac vein.
Both Ureters can be joined together and anastomosed to bladder or can be reimplanted separately .
Kidney donation based on eGFR-
e GFR > 60 ml/min- Single kidney donation
eGFR 30-60 ml/min- Dual transplant
eGFR < 30 ml/min – Cannot donate
Kidney donation from marginal donors- History of diabetes, hypertension, age> 60 yrs, CVA, IHD, Proteinuria > 3 gm/day
Donor kidney renal biopsy assesses the Glomerulosclerosis, interstitial fibrosis, tubular atrophy and arterial narrowing-
The Remuzzi Score
0-3- Single kidney transplant
4-6- Dual renal transplant
>6- Discard.
Dual transplant- ideal recipient.
Elderly recipient do better than younger ones
PRA <5%
First transplant
BMI < 30
Less medical conditions.
Conclusion-
Dual transplant has increased donor pools.
Results of graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
Use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes
Selection criteria for DKTs are still variable and center dependent.
Narrative review
Level V
Thankyou
Please provide a summary of this article
REVIEW ARTICLE – EVIDENCE LEVEL V
Introduction:
Due to increased waiting list for kidney transplant in the last decades, the trend to accept donors from age extremes (pediatrics and older) donors, extended criteria donors(ECD) > 60 Years or > 50 Year old with history of HTN, cardiovascular cause of death, serum creatinine at retrieval of 1.97 mg/dl.
Donors from cardiac death patients and pediatrics had nephron mass loss, which may be affected with episodes of acute rejection, immunosuppressive medications, and recipient’s comorbidities after kidney transplantation. Raise the dual kidney transplant idea in several transplant centers in order to over come these marginal kidneys outcome, the first dual kidney transplant done in USA in 1996 by Johnson and colleagues.
Which kidney is suitable for dual transplant?
Several studies were published in dual kidney transplant with different protocols, with no obvious straight forward guidelines for such practice.
Remuzzi and associates, suggested a scoring system based on pre-transplant biopsy for selection of a kidney for DKT. Brain dead donors older than 60 years, donors who were diabetic, or donors with presence of proteinuria of less than three grams/24 hours were considered. Kidneys with macroscopic major vascular abnormality or evidence of focal scarring were excluded. Both kidneys were biopsied, and those with less than 25 glomeruli were excluded. Dual kidney transplants were performed if a priori score was between 4 and 6. In the 24 DKTs reported in the study, patient and graft survival was 100% at 6 months.
In a review of UNOS database published on 2008, 525 DKTs were performed from 2000 to 2005. Donors were considered for DKT if any 2 of the following criteria present: age greater than 60 years, creatinine clearance greater than 65 mL/min, rising serum creatinine greater than 2.5 mg/dL at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy between 15% and 50%. Three-year graft survival was 79.8%.
The limitation is the surgeons take an elliptical biopsy from kidney surface, this due to the fear of bleeding or arterio – venous fistula formation in needle biopsies. This could be misleading and overestimate the glomerulosclerosis, as glomeruli sclerose from outside in, leads to excess in organ discard for marginal kidneys, thus, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead of biopsy. Donors older than 65 years with one of the following risk factors were considered: HTN, T2DM, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT. Snanoudj and associates performed 81 DKTs using this protocol, with 2-year graft survival of 90%.
Who is a suitable recipient?
Matching age and size of donors and recipients in ECDs, best suggested for DKTs, they had nephron loss, less risk for rejection, limited life span for the elder recipients, this was ideal to low immunological risk recipients whom no history of previous transplant, and PRA <50%.
DKT is offered to patients 60 years or older, offering DKTs to patients with low immunological risk, who are less than 60 years old, and minimal comorbidities and body mass index < 30 kg/m2 recipients.
Surgical techniques
Different approaches were dicussed with the potential complications, special concern to kidneys from pediatric donors illustrated, however these procedures needs expert team to perform them, to decrease the complications risk.
Graft and patient survival
Different data from several studies on patient and graft survival, but it was equivocal or better among DKTs versus SKTs. Surgical complications were more in DKTs.
Complications
Higher postoperative admission rates to an intensive care unit (more among DKTs).
Wound dehiscence (more among DKTs).
Early renal graft thrombosis (more among DKTs).
Urinary tract complications- fistulas, ureteric stenosis (comparable).
Recipients of DKT have a higher risk of developing myocardial infarction (more among DKTs).
Reduced dissection time and low lymphocele risk in ipsilateral DKTs versus bilateral DKTs.
Infections were less among ipsilateral DKTs.
Conclusions
DKTs increased the pool of potential organs by increasing use of marginal kidneys.
Ipsilateral placement of both grafts is widely accepted with less complications comparable to SKTs.
Graft and patient survival, complications, and quality of renal function provided by DKTs are comparable to SKTs.
Up to now no clear criteria to choose either DKTs vs SKTs among ECD, this make it wise to standardize criteria for DKTs allocation.
Well done but although the Remuzzi score is time consuming and not prefer Ed by some but proteinuria even less tha 3gm a biopsy is a must and might show surprises.
Thank you Prof. Dawlat
Introduction
In the past few decades, dual kidney transplantation has enabled a larger use of kidneys that were considered to be on the verge of failing and has shortened the waiting period. Both the absence of a well-defined allocation policy and the fact that clinicians alone are responsible for making judgments about dual kidney transplants, are obstacles that prevent many centers from implementing DKT program. The implantation of both kidneys on one side is the approach that is preferred in many different centers.
Although there is a higher incidence of vascular complications, primarily in the form of graft thrombosis, the overall complication rate is comparable between single and dual kidney transplants. Kidney survival and function are encouraging and close to results with a single kidney transplant using conventional criteria.
One marginal kidney (from ECDs, donors with cardiac death, or pediatric donors) may not have enough functional nephrons to allow a receiver to become dialysis independent after transplantation. In order to expand the available “nephron mass,” the practice of transplanting both kidneys from a single donor into a single recipient as a dual renal transplant has gained popularity.
Which kidney is suitable for dual transplant?
One reason why DKTs are not commonly performed at many transplant hospitals is that there is no universal consensus on which donor kidney is best for DKT. In addition, there are distinct criteria for choosing kidneys due to the fact that surgical practices and protocols vary widely from one institution to the next.
A total of 525 DKTs were reported between 2000 and 2005 in a review of the UNOS database published in 2008. Donors were selected for DKT if they fulfilled 2 out of the following 4 criteria: age >60, creatinine clearance >65 mL/min, serum creatinine >2.5 mg/dL and rising at retrieval, chronic hypertension or type 2 diabetes mellitus, and glomerulosclerosis on biopsy 15%-50%. The three-year graft survival rate was 79.8%.
Remuzzi and colleagues proposed a pretransplant biopsy-based grading system for selecting a kidney for DKT in 1999. Dual kidney transplants were performed for patients with an a priori score between 4 and 6. Six months after the 24 DKTs reported in the study, both patient and graft survival were 100%.
In a 2000 trial conducted by a Spanish group, brain-dead donors with normal serum creatinine levels were considered for DKT if they were at least 75 years old.
United Kingdom Kidney Advisory Group recommended that kidneys from donors aged 70 or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, MI, type 2 DM, CV event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
who is a suitable recipient?
Numerous authors recommend matching recipients with donors based on their age and size. Given that the majority of DKTs involve donors at extreme ages, it is proposed that older donors be paired with older recipients.
Surgical technique
Johnson and colleagues described the first DKT, which involved bilateral Gibson incisions and the transplantation of one kidney on each side. However, this technique requires more tissue dissection and loner operative time.
A midline extraperitoneal approach was described to minimize dissection and operative time. Haider and associates described this technique in 2007.16 The single midline incision has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision.
Unilateral placement of both kidneys was described by Mason and Hefty in 1998.
Graft and patient survival
The earliest report of DKT documented 100% graft and patient survival in 9 DKTs.
Lee and associates reported similar patient and graft survival at 1 year (98% and 89% in DKT vs 97% and 90% in SKT) and 2 years (86% and 77%).
UNOS database from 2000 until 2005 followed 625 recipients of DKT for 48 months. Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%.
A French team with older donors (age, 75 ± 5.8 y) recorded DKT patient and graft survival at 3 years that reached around 50%.
In a study of ECD donors, D’Arcy and associates from Ireland reported superior 3-month patient (92% vs 100%) and graft survival (88% vs 93%) in recipients of SKT vs DKT.
Complications
Due to technical obstacles, longer operative time, and inferior kidney quality, complications with DKT are believed to be greater. Following complications were more frequently observed with DKTs.
local wound dehiscence
Early renal graft thrombosis
Urinary tract complications (fistulas requiring surgery)
Ureteric stenosis
Ureteral complication or urine leak
Wound infection
Well done Thankyou
1.Please provide a summary of this article
Introduction
·A wide gap exists between the numbers of ESRD cases on the DKD waiting lists & the number of deceased donors available.
This fact has dictated the use of ECD for donation.
·Donor age was reported to have adverse effect on graft survival in most studies.
·Patient survival in the 1st & 2ndyear post-transplant were similar between ECD & SCD donors.
·However, graft survival & function were reduced with increased incidence of DGF & AR events.
·DGF & AR events are reported as risk factors for graft failure (Ferrer et al).
·Some studies reported that there is no significant relation between donor age & 5-year graft function.
·So, donors previously deemed as not suitable are now acceptable.
·This retrospective single center study reports outcomes of patients transplanted by kidneys from elderly donors (=/> 60).
The study
Population
All patients who received DKD grafts from elderly donors (=/> 60 at SKI between 3/1969 & 2/2009.
Exclusion criteria:
DKD transplants from donors < 60 years.
LKD transplants of any donor age.
Transplants before 3/1969 or after 2/ 2009.
Aim
To determine graft & patient survival outcomes of kidney transplants from elderly donors.
Donor factors:
Age
Sex
Serum creatinine
eGFR
CIT
HLA mm
HLA-DR only mm
Total follow-up,
Total duration of graft survival
Graft & recipient survival at 1, 3, & 5 years post-transplant
AR episodes
Recipient factors:
Patient status (dead or alive)
Age
Sex
Co-morbidities (CVD, T2DM type 2, CVD, &HTN)
Type of IS agents used
Number of AR events
DGF
eGFR (MDRD equation) at 3, 12, & 60 months post-transplant.
Graft loss or non-graft survival was defined by a creatinine rise requiring RRT.
Recipient death was defined as non-patient survival.
Statistical analyses done with SPSS Software.
Results
· A total of 112 TX were done during the study period.
· Total number of donors: 112 donors.
· 59 of the donors are females (52.7%).
· Mean donor age: 64.71 +/- 4.
· Of 112 recipients, 38 are females (33.9%).
· Patient survival at 1 yr was 91.9%, at 3 yrs 82.1 %, & at 5 yrs 78.2%.
· Graft survival at 1 yr was 80.4%, at 3 yrs 67.7%, & at 5 yrs 63.6%.
· Donor age ( P = .008) & donor serum creatinine level (P = .011) were significantly associated with total duration of graft survival.
· Age differences (P = .001), donor eGFR (P = .04), & donor age (P = .03) are predictors of total duration of graft survival. Donor eGFR & age had negative impact on graft survival.
·Better cumulative graft survival was associated with the use of kidneys from donors with eGFR of 60 mL/min as compared to those with eGFR <60 mL/min.
·In a multivariate analysis donor age was not a significant predictor duration of graft survival (P> .05), while AR events (P< .001) & donor eGFR (P = .035) significantly predicted cumulative graft survival.
Discussion
·Expanding the criteria for deceased donors ECD was dictated shortage of donor organs for kidney transplant.
·Graft function was independent of age of the donor.
·The authors found no significant effect of donor age when considered with other donor variables (e.g. kidney function) & donor-recipient variables (DGF & AR).
·CIT, recipient co-morbidity, & total number of HLA mm are also not associated with any short or long term effect on graft survival.
·Opelz et al. (data from Collaborative Transplant Study) reported that HLA mm significantly affected the outcome of kidney transplants.
·Reisaeter et al.(655 non-sensitized recipients of DD grafts):
-1-yr HLA-DR m graft survival 90% vs 82% & 73% for 1 & 2 HLA-DR mm grafts.
– 5-yr survival rates were 76%, 62%, & 56%.
– HLA-A & HLA-B did not improve overall graft survival but improved graft survival at 1 yr.
·Moreira et al. (997 DD kidney transplants) reported an incidence of DGF of 19%.
·DGF was quite high (40.2%) in the current study; this may indicate that kidneys from elderly donors are more susceptible to DGF.
·Moreira et al. also report that DGF significantly reduced long-term graft survival without any effect on patient survival.
·In this study, DGF had no long-term effect in the elderly donors who were > 60 yrs.
· Donor eGFR has significant associated with duration of graft survival.
· The significant association between eGFR & graft survival may indicate that the quality of donor kidneys (eGFR) is more important than age.
· Ferrari et al. showed no significant effect of age difference on patient & graft survival in LDK transplant; however, the current study shows that age difference predicts graft survival. This may indicate a role for age difference in DKD transplants in the presence of other risk factors.
·High incidence of AR episodes in the study (33.9%) could be due to the high incidence of DGF or to reduction of IS therapy done to help the elderly kidneys recover from DGF.
·Patient survival in the study is comparable with other single center survival results.
Conclusions
·Deceased elderly donors kidneys may significantly expand the donor pool if the associated risk factors are avoided.
·Better donor selection based on eGFR is related to better post-transplant function & better graft survival.
·Better HLA-DR m kidneys gives better outcome.
A shorter summary would be better
LDT as exclusion criterion?.????
but good work
Dual kidney transplant refer to transplantation of two kidneys from a marginal donor in one recipient that is theoretically may increase graft survival.
Technique
Ideal Donor for DKT should has the following 3 requirements
1- GFR
2- Donor kidney should be a marginal kidney taken from the following type of patients:
·
3- Donor renal biopsy
Addressing 4 parameters including assessment of glomerulosclerosis, interstitial fibrosis, tubular atrophy and arterial/arteriolar narrowing.
Ideal recipient for DKT:
1) Age; elderly may be better candidates for DKT due to the following:
2) Having lower immunologic risk (PRA less than 5%, first transplant)
3) Minimal co-morbidities especially atherosclerotic vascular diseases (due to technical difficulties in vascular anastomosis)
4) BMI less than 30 or body weight less than 80 kilograms (to prevent post-operative surgical complications like wound dehiscence)
Outcome
Well done
Summary:
Introduction:
Which kidney is suitable for dual transplant?
Who is a suitable recipient?
Surgical technique
Mason and Hefty1998:
Right kidney placed superiorly (RA–> CIA, RV –> IVC)
Clamps were released, allowing perfusion of transplanted kidney
Left Kidney (RA–>EIA, RV–>EIV)
The conjoint ureters were anastomosed to the bladder with ureteric double J stent.
Esker method:
Right kidney placed superiorly(RV–>EIV)
Transplant ureters had 2 separate extravesical ureteroneocystostomies on ureteric stents. The upper kidney ureter was placed lateral to the lower kidney ureter.
Many surgeons now prefer this technique for DKT
Adv: Less dissection
Authors preference:
Extend the short right renal vein using the donor inferior vena cava–>recipient’s IVC.
RA–> CIA
En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
Outcomes:
Complications:
y have all the information but with minimal organization.
Please provide a summary of this article
-Renal transplant is the treatment of choice for patients with end-stage renal disease. To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested.
-Extended criteria donors include donors older than 60 years or those who are older than 50 with a history of hypertension, had cause of death due to cerebrovascular events, or have serum creatinine level
at retrieval of more than 1.97 mg/dL.
-The transplant of a single marginal kidney (from ECDs, donors with cardiac death, and pediatric donors) may result in a suboptimal number of functional nephrons to allow recipients to become dialysis independent. Episodes of acute rejection, medication toxicity (particularly from calcineurin inhibitors), and effect of the recipient’s comorbidities on the transplanted kidney will adversely affect these
limited functional nephrons.
-The concept of trans – planting both donor kidneys into 1 recipient as dual renal transplant has been adopted to increase available “nephron mass.” The hypothesis is, if 2 marginal organs are given to the same recipient, more functioning nephrons should be available versus with a single suboptimal organ or as many functioning nephrons versus with a single idealkidney.
– Transplanting 2 kidneys to the same recipient effectively prevents progressive deterioration in renal function compared with single
transplant controls.
– Dual kidney transplant carries a potentially higher risk of surgical complications because of the longer surgical procedure and the 2-fold risk associated with double vascular and ureteric anastomoses.
– Remuzzi and associates suggested a scoring system based on pretransplant biopsy for selection of a kidney for DKT.
– Five-year survival was 80% when protocol biopsy showed no glomerulosclerosis and dropped to 35% when sclerosis was > 20% in donated kidneys.
-Some authors also have reported higher delayed graft function (80%) with sclerosis > 20%.
-One of the limitations is that most surgeons obtain an elliptical biopsy from kidney surface. This could be misleading as glomeruli sclerose from outside in. As a result, these biopsies could overestimate
glomerulosclerosis. Needle biopsy is usually avoided by surgeons because of risk of bleeding or arterio – venous fistula formation.
– Greater use of kidneys for DKT that are more suitable for SKT could result in a reduced organ pool for transplant.
-To avoid biopsy-based decisions, the estimated glomerular filtration rate (eGFR) in the donor as a criterion was used instead.
– Donors older than 65years old with at least 1 of the following risk factors were considered: hypertension, type 2 diabetes mellitus, atherosclerotic disease, or death from a cardiovascular event. Depending on maximal eGFR calculated with use of the Cockcroft and Gault formula, donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
-United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of
> 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
-Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus.
-Kidney donations after cardiac death are generally considered marginal because of warm ischemic injury.
– Many authors suggested DKT with matching recipients with donors by age and size and recipients with lower immuno -logic risk (ie, recipients without previous transplant and panel reactive antibody titer < 50%).
-The earliest report of DKT documented 100% graft and patient survival in DKTs.
– The quality of DKT function is as important as how long it will keep functioning since the aim is to keep the patient dialysis independent for as long as possible. Many factors affect graft function, including
donor factors, donation circumstances, cold ischemia time, and perioperative events.
– In multivariate analysis, DKT had a protective effect against delayed graft function . Kidney discard rate was 3 times lower when the high-risk ECD kidneys were offered as DKT.
-Complications with DKT are perceived to be higher due to technical difficulties, with longer operative time and lower kidney quality.
-Urinary tract complications also have been reported to be slightly higher, especially urinary tract fistulas requiring surgery . The kidneys for DKT were from older donors; these more atherosclerotic vessels
might suggest this higher risk.
-Postoperatively, recipients of DKT have a higher risk of developing myocardial infarctions when compared to SKT candidates.
-Monolateral placement of both kidneys reduces length of the surgical procedure and hospital stay.
-A larger study also showed no differences in complication
rates between ipsilateral DKT and SKT.
-The ipsilateral placement reduced dissection time and made lymphocele risk similar to that for SKT procedures.
-Thrombosis of renal vein, artery, or even the donor’s aorta was observed.
Well done
● Dual kidney transplant has enabled greater use of marginal kidneys and reduced waiting time
● The overall complication rate with dual kidney transplant is comparable to single kidney transplant.
● Use of kidneys from donors from age extremes (pediatric or elderly) has been suggested for increase pool donors
● Dual kidney transplant carries a potentially higher risk of surgical complications
● Most of DKTs were from donors > 65 years
● which kidney is suitable for dual transplant?
* Donors older than 60 years
* Long history of hypertension or diabetes * Cold ischemia time less than 30 hours
* CrCl between 80 and 40 mL/min
* Kidneys showed < 40% GS without IF or arteriosclerosis on biopsy
* Rejected Single Kidney by other units
* Remuzzi criteria 4 – 6
● who is a suitable recipient?
* Older recipient > 60 year
* Lower immunologic risk low who are less than 60 years old, and who have minimal comorbidities and BMI < 30 kg/m2.
● Surgical technique
The right kidney was placed superiorly with renal artery anastomosed into the common iliac artery and renal vein into the inferior vena cava. And left kidney vascular pedicle to external iliac vessels.
● En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
● Concerns related to pediatric EBK
* More difficult surgical anastomosis,
* Inadequate nephron mass
* Relative sensitivity of pediatric kidneys to rejection
* Hyperfiltration injury
● Complications :
* Early renal graft thrombosis
* Urinary tract complications
* A higher risk of developing MI in DKT recipiants
● Results of graft and patient survival, complications, and quality of renal function
provided by DKTs are comparable to SKTs
Well done comprehensive.
VI. Dual Kidney Transplant
====================================================================
ntroduction
==============================================================
which kidney is suitable for dual transplant?
Pretransplant Biopsy Scoring System
Pretransplant Biopsy Protocol
Glomerular Global Sclerosis:
Based on 3 sections (First, Middle and Last if
available), the number of globally sclerosed glomeruli expressed as percentage
Tubular Atrophy
Interstitial Fibrosis
Arterial and arteriolar narrowing:
For the vascular lesions, if the changes are focal, the most severe lesion present gives the final grade
1- Increased wall thickness but to a degree that is less than the diameter of the lumen
2- Wall thickness that is equal or slightly greater to the diameter of the lumen
3 -Wall thickness that far exceeds the diameter of the lumen with extreme luminal narrowing or occlusion
=============================================================
who is a suitable recipient?
==============================================================
Surgical techniquethe
====================================================================
Graft and patient survival
====================================================================
Complications
==============================================================
Conclusions
Long as usual but excellent
Summary
This study reviews the current practice for Dual kidney transplantation (DKT), there is no standardized guideline for DKT, and most of the evidence available from local centers’ experience, and the decision for DKT is based on clinical judgment with preferred surgical techniques of unilateral grafting or en block transplantation more in the pediatric population taken in consideration the vascular complexity, the graft and patient survival are comparable to the outcome of SKT but surgical complication including vascular thrombosis should be taken carefully in DKT.
The DKT started in 2003 according to the data from the united network of organ sharing (UNOS ) as part of ECD selection and after cardiac death with marginal kidneys from ECDs, pediatric donors with low nephron mass and prolonged warm ischemia time which further affects the limited nephron mass by CIT, acute rejection drug toxicity ( CNI ) and recipients comorbidities which can impact the graft survival and outcome so the concept of DKT in one recipient in order to raise the functioning nephron mass which has been confirmed from animal and human studies that increasing the size of viable nephron mass successfully improved graft function.
No consistent allocation criteria for DKT, it depends on the local center-based experience with diverse allocation criteria
UNOS database registry reported in 2008 data of 525 DKT surgery done between 2000-2005 and the selection criteria for DKT based on donor age > 60 with creatinine clearance > 65ml/min and raising creatinine > 2.5mg/dl at the time of organ retrieval, along donors’ history of HTN, DM type2 and biopsy score of GS 15-50% with 3-year survival was almost 80%.
In another Italian series of 100 DKT done between 2003-2009, allocation criteria were based only on donor age with, the mean donor age being 72 and true cut biopsy histological criteria between 4-6 for DKT and again the overall three-year graft survival was 90%.
Donors selected between the age of 60-69years with creatinine clearance above 60ml/min, and negative medical history for DM, HTN with normal serum creatinine no pre-OP biopsy indicated, and can be selected for SKD (esker and associate)
Kidney biopsy pre-OP has its limitations being invasive with the associated risk of bleeding and AVF in addition to variation in reporting these biopsies might be misleading and result in unnecessary organ discard so alternative to that some centers use the clinical donor’s criteria along with e GFR level by Cockcroft gault formula.in donors above the age of 65years with one or more of the medical comorbidities like HTN, type 2DM, death with CVA or CVD
GFR > 60ml/min for SKD
GFR 30-60ml/min allocation for DKT
GFR < 30ml/min the organ should be discarded
The above selection criteria were Studied by Snanoudj in 81 DKT with 2 years graft survival reached 90%
UK kidney advisory group proposes that donors above the age of 70s with a medical history of one or more of HTN, MI, type 2 DM, or CVA as the cause of death with a serum creatinine of 1.97mg/dl at the time of donation, presence of any anatomic variance (like RAS, PCKD) Small size kidneys) preferred to be used for DKT
Another group from Newcastle the use hypothermic machine perfusion pressure index as part of the selection criteria for DKT in donors from Maastricht categories 2, 3 with glutathione transferase level ( one enzyme marker for ischemic injury ).
Surgical complications of DKT
include longer procedures in compromised recipients lead to a higher rate of post-operative ICU admission, especially with double vascular and ureteric anastomosis, and vascular thrombosis, and the surgical complication even more in pediatric enblock procedures due to technical difficulties with vascular anastomosis and longer operative time, space in case of size difference with risk of functional and structural hyperfiltration and Secondary FsGS, urinary tract surgical complications with fistulas and ureteric stenosis.
Selection of the recipients for DKT
preferred to be age and size mass match, less comorbid diseases, low immunological risk means no previous transplantation and PRA < 50% this will allow to spare them the CNI toxicity risk with the use of CNI minimization or CNI free protocol
Excellent
Summary:
Renal transplant is the treatment of choice for patients with end-stage renal disease. All over the world, there is a shortage of organs available for donation. To increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) has been suggested. In late 2003, UNOS implemented the use of kidneys from extended criteria donors. Donations after cardiac death also have been accepted worldwide.
The transplant of a single marginal kidney may result in a suboptimal number of functional nephrons to allow recipients to become dialysis-independent. The concept of transplanting both donor kidneys into 1 recipient as a dual renal transplant has been adopted to increase available “nephron mass.
which kidney is suitable for a dual transplant?
There is so far no global consensus as to which donor’s kidney is best for DKT, with one reason being that DKTs are not routinely performed in many transplant centers. In addition, the variations in practice and protocols between different surgeons and centers have led to differences in kidney selection criteria.
who is a suitable recipient?
Similarly, there is debate about the best candidate for DKTs. Many authors suggested matching recipients with donors by age and size.
In general, DKT is offered to patients 60 years or older, patients with low immunological risk who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2.
Surgical technique
the original technique included a bilateral Gibson incision and the transplanting of 1 kidney to each side. This method required more tissue dissection and a longer operative time.
A midline extraperitoneal approach was described and it has the advantage of a shorter operative time and dissection and fewer hernia complications in comparison to a bilateral Gibson incision. In addition, a potential wound infection would be far away from the graft.
Pediatric kidneys have a higher risk of surgical complications, especially vascular as a result of small vessel size. En block kidney transplant using a pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
Graft and patient survival
Complications
Excellent
thank you
Introduction:
Kidney transplantation proved to be the treatment of choice for patients suffering from End Stage Kidney Disease (ESKD) as it will improve the quality of life and decrease mortality. However, the global shortage of suitable organs for transplantation remains a major obstacle.
One possible solution was to use double kidney transplantation (DKT) of a marginal kidney that would have been unsuitable for single kidney transplantation (SKT). Johnson and his colleagues performed the first adult DKT in 1996 after about two decades of the first paediatric DKT. Afterwards, several approaches to DKT were adopted by different centres.
DKT was not a popular option due to many reasons, which include: complex technique (double ureter and vascular anastomosis), prolonged operative time, higher peri-operative complications, and lack of standard criteria for DKT (regarding both donor and recipient criteria). However, the introduction of the Remuzzi score in 1999 provided a helpful tool for allocating deceased kidneys to DKT or SKT based on kidney biopsy findings.
Possible surgical techniques for DKT:
· Bilateral Gibson incision and transplanting of one kidney to each side:
Described by Johnson and associates. The technique was associated with prolonged operative time and more dissection for bilateral placement of allografts, which significantly increased peri-operative complications.
· A midline extraperitoneal approach:
A midline infra-umbilical incision with blunt dissection of extraperitoneal space to expose the iliac vessels bilaterally, and then one allograft will be placed in each side. This technique had the advantages of shorter operative time and lower risk of incisional hernia. Additionally, whenever there is wound infection, it will be away from the allograft.
· Unilateral placement of both kidneys:
In this technique, the right kidney allograft was placed superior to the left kidney, with the arterial anastomosis to the common iliac artery for the right kidney and the external iliac artery for the left allograft. The venous anastomosis for the right kidney will be with the IVC, and the left allograft with the external iliac vein. This technique had lowered the operative time further. Moreover, this approach preserved the contra-lateral iliac vessels for any future transplantation whenever needed.
· En block kidney transplant:
A technique that was initially described in paediatric DKT. This technique utilizes the donor aorta and IVC to be anastomosed with the external iliac artery and vein.
Patient and allograft survival:
Generally speaking, the overall patient and allograft survival with DKT from ECD were comparable to SKT from SCD. The primary documented complications were mainly related to surgical complications due to the challenging operative demands, wound infection, anastomotic leak and allograft vascular complications. Nevertheless, other factors may also affect the outcome as the donor age, prolonged cold ischaemia time, and donation circumstances.
Study designs and level of evidence:
This article is a narrative review which makes it level 5.
Limitations of the study:
The study is a review of retrospective, single-centre trials with no standardization of the donor or recipient characteristics. Therefore, the data provided needs more validation through more organized prospective trials.
Very good but you missed the UK Kidney Advisory Group method which is more practical tha than the Remuzzi score which will make an impact on the second WIT
To mitigate the need for kidney recipients, dual kidney transplant has increased the pool of potential organs by increasing use of marginal kidneys. This review article showed, graft and patient survival, complications, and quality of renal function provided by dual kidney transplants are comparable to standard kidney transplants. Moreover, the use of pediatric kidneys by an en block technique into adult recipients has resulted in similar encouraging outcomes despite the higher surgical complication rate. Donor age, clinical and histopathological findings, baseline renal function, should take into consideration.
Too short.
Very good but please revise the UK Kidney Advisory Group as you did not mention the eGFR to start with!
Introduction
ECD have been an option to face the increased demand of organs due to the shortage of available organs .
Organs retrieved from DCD donors are considered as marginal organs due to the warm ischemia time.
Transplanting a single marginal kidney from an ECD ,or DCD or paediatric donor provides insufficient functional nephron mass for recipients therefore dual kidney transplantation (DKT)policy was adopted to get use of those marginal kidneys by increasing the number of functioning nephron by transplanting to suboptimal kidneys in a single recipient and decrease the waiting list candidates.
DKT is carried out in multiple centres by variable techniques and organ selection criteria.
Although it carries high potential risks of surgical complications , it’s results are acceptable.
Absence of definite guidelines ,allocation criteria and suboptimal grafts lead to the reluctancy of different centres to apply DKT policy.
Kidneys suitable for DKT
There are no standerdised criteria available for organ selection for DKT.
Johnson et al used kidneys from donors elder than 60 years with hypertension or diabetes history, having cold ischemia time < 30 hours, with creatinine clearance ranging from40 -80 mL/min and with kidneys < 40% glomerulosclerosis without severe interstitial fibrosis or arteriosclerosis on biopsy they demonstrated that at 6 months the patient and graft survival were 100%.
Remuzzi at al,1999 designed a scoring system depending on biopsy done before transplantation to select a kidney for DKT . DBD donors > 60 years whom were diabetic, or with proteinuria < 3grams/24 hours were included excluding kidneys with less than 25 glomeruli and those with vascular anomalies.DKT was done if a priori score was between 4 and 6.
DKT was performed in 2000 in Spain from DBD donors with normal serum creatinine , aged >75 y and 60-74 y with 15%-50% glomerulosclerosis were included but they transplanted kidneys with <15% glomerulosclerosis and discarded those with > 50 % glomerulosclerosis .
In 21recipients at 6 months graft survival was 95%.
UNOS at 2000 studied 525 DKT cases within 5 years and found that graft survival was 79.8% at 3 years .
In Italy unilateral DKT was performed and results revealed graft survival of 90.9% at 3 years .A truecut needle was used for biopsies.
Protocol biopsy that showed no glomerulosclerosis had 5 years graft survival of 80% and decreased to 35% when sclerosis was > 20% in the kidneys.
There are some limitations as needle biopsies are not preferred due to bleeding risk and AV fistula formation that can occur also biopsies can overestimate glomerulosclerosis along with variable interpretation.
Unexpectedly the increased use of kidneys for DKT
that are more fit for SKT could lead to reduction of organ pool for transplant.
eGFR was used now to avoid decisions depending solely on biopsy results.
eGFR > 60 mL/min were considered for SKT, eGFR < 30 mL/min was discarded, and eGFR between these results was an indicator for DKT form donors> 65 y with certain risk factors.
Using such a policy 2-year graft survival reached 90% in 81 DKT cases.
The advisory kidney group in UK adviced that donors aged 70 years or more can be included in DKTs
if 1 or more of these risk factors were found as hypertension history ,MI , type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level > 1.97 mg/dL at retrieval, or any anatomic anomaly presence.
Some centres add to it prolonged warm ischemia time, , eGFR < 60 mL/min, kidneys with multiple cysts.
New Castle team documented in 2008 results of DKT outcome of donors with Maastrichit category 2 and 3 having HMP.Donors were chosen for SKT or DKT according pressure flow index and glutathione transferase,DGF rate was 81% but 3-month GFR was 46.2 ± 13.7 mL/min.
Pediatric SKT is debatable. Hobart et al adviced using en block kidney transplant when donor age is < 2 years.
Appropriate recipients
It is controversial too but it was suggested to match recipients and donors according to age and size.
Others adviced to consider elder recipients due to their lower life expectancy and acute rejection rates and those with low immunological risk.
Contrarily others considered younger recipients as they will cope better with the longer operative time needed for DKT .
Surgical technique
A midline extraperitoneal approach was introduced
to minimize dissection and operative time in comparison to the classical method added to this it can be turned to intraperitoneal approach, on the other hand it has higher ileus and bowel complications,
mobile grafts, and taking a biopsy will be more difficult.
In 1998 Mason and Hefty reported the unilateral placement of both kidneys preserving the other side for possible future transplantation and having similar 1 year graft survival as bilateral technique and less operative period taken.
Ekser et al introduced some modifications that lead to renal vein thrombosis in 2 of the studied cases in the unilateral group. This technique has shorter operative time and hospital stay and a lower GDF compared to bilateral technique of DKT .
Also unilateral DKT had similar outcomes to SKT .
Pediatric kidneys are at higher risk of complications.
EBK modification was introduced by NewCastle team by transposing the infrarenal aortic and IVC segment of the donor to the top, and the new inferior stump was stitched. The new vascular pedicle was anastomosed to iliac vessels, so that kidneys can drop to the extraperitoneal pelvic space, with favourable results.
Graft and patient survival
DKT recipients had better graft function than recipients of SKT from donors > 60 y or from donors < 50 y.
The 2007 UNOS review within 5 years following cases for 48 months ,the recipients of DKTs from ECDs had similar death-censored graft survival, that was 70% and recipients of kidneys from standard criteria donors had better survival of 80%.
In a French study ,using older donors the DKT patient and graft survival at 3 years was nearly 50%.
A Spanish report mentioned that DKT and SKT from old donors nearly had the same graft and patient survival outcome at 1 year interval opposite to an Irish study that reported SKT to have a better graft and patient survival in a 3 months period but follow up at 3 years showed that the outcome was comparable to DKT from ECD.
EBK transplant of paediatric donors into adults had acceptable results.
The quality of DKT function is mandatory to be sufficient to keep the recipient dialysis independent.
This is affected by multiple factors as donor factors, donation circumstances, cold ischemia time, and perioperative events.
The UNOS 2008 report published that DKT recipients whom experienced prolonged cold ischemia time , had lower DGF than SKT from ECD and similar to SKT from standard donors.
For DKT recipients , PNF was 1.8% .
New Castle study demonstrated similar e GFR at 3 and 12 months posttransplant for DKT from DCD donors compared to SKT.
En block kidney transplant was associated with slight increased risk of graft loss compared to SKTs.
Paediatric EBK has more difficulties as surgical anastomosis increasing complications risk, low nephron mass, more liability to rejection, and
hyperfiltration injury that can lead to FSGS.
Complications
DKT complications are higher due to technical difficulties, and longer operative time and lower kidney quality.
These complications include wound dehiscence ( reported in 5% ) , early renal graft thrombosis ,urinary tract fistula, vascular thrombosis,postoperatively recipients were more liable to MI.
It was reported that there is no differences in complication rates between ipsilateral DKT and SKT.
Studies demonstrated higher complication rates for EBK compared to SKT.
Wandering kidney can mislead diagnosis .
Conclusion
DKT from marginal donors increased the pool of organs available.
Unilateral placement of both grafts have comparable outcomes to SKT.
Standardized criteria is needed for DKT kidney allocation.
Excellent
The demand for renal transplants increases as the number of patients on the waiting list is rising. In the last decade, major advancements in kidney transplantation occurred, and the use of marginal kidneys is increasingly acceptable to fill the gap between demand and supply.
The transplant of a single marginal kidney (from ECDs DCD / DBD or pediatric donors) may result in a suboptimal number of functional nephrons, and nephron mass is a determinant of long-term graft function. Therefore, dual kidney transplantation evolved by using 2 marginal kidneys in the same recipient to increase nephron mass.
Several reports showed the acceptable outcome of using DKT. There are no clear guidelines, allocation policies, and practice varies among centers.
Which kidney is suitable for a dual transplant?
There is so far no consensus for DKT selection criteria, variation in protocol and practice among centers.
Remuzzi scoring system based on pre-transplant biopsy to select a kidney for DKT. Both kidneys were biopsied, and DKT was done if score was between 4-6. Sometimes, biopsies overestimate glomerulosclerosis when taken superficially.
Incorporating donor age and clinical and histologic findings for better decisions.
Another approach to use maximal eGFR calculated along with clinical data on comorbidities donors with eGFR > 60 mL/min were considered for SKT when eGFR 30-60 indicate DKT, and if eGFR < 30 Kidneys were discarded.
Hypothermic machine perfusion can guide the decision by measuring Pressure flow index and glutathione transferase GST concentration.
Kidneys were used for SKT if the pressure flow index was 0.4 mL/min per 100 g/mm Hg and GST was less than 100 IU/L/100 grams renal mass.
The kidneys were discarded if the pressure flow index was less than 0.4.
Kidneys were considered for DKT if the pressure flow index was satisfactory, but GST was higher than the cutoff value for SKT or if other risk factors were present (e.g., comorbidities or cold ischemia).
Using en block kidney transplant (EBK) when the donor ages less than 5 years.
Who is a suitable recipient?
– Matching recipients with donors by age and size.
– Elderly individuals have limited metabolic demands would not require graft survival of greater than 20 years
based on their expected lifespan; therefore, using kidneys with limited nephron mass is justified.
– DKTs to recipients with lower immunologic risk (recipients without previous transplant and PR < 50%), to reduce possible injury to limited nephron mass.
– Preferably offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and BMI < 30 kg/m2.
Surgical technique:
– Bilateral Gibson incision and transplanting 1 kidney to each side; more dissection and a longer OR time.
– A midline extraperitoneal approach with bilateral implantation; shorter OR time and dissection and fewer hernia
– Unilateral placement of both kidneys, the contralateral side remained untouched for possible future transplant
Graft and patient survival
Recipients of DKTs from ECDs had similar death-censored graft survival, which reached 70%.
During the same follow-up, recipients of kidneys from standard criteria donors had better survival of 80%.
UNOS database showed that DGF incidence (29.3%) was lower than shown in recipients of SKT from
ECD (33.6%) and similar to recipients of SKT from standard criteria donors (28.3%). Primary nonfunction was as low as 1.8%.
Outcomes of EBK UNOS database showed a slightly increased risk of graft loss (aHR, 1.18) compared to SKTs. DGF was reported in 17.9% of EBK, with 23.44% in the SKT arm.
Complications:
Challenges include technical difficulties, longer operative time and lower kidney quality.
– local wound dehiscence rate of 5%.
– Early renal graft thrombosis 12%
– Urinary tract complications; fistulas requiring surgery, ureteric stenosis.
– Myocardial infarctions (12% vs 0%); in recipients of DKT when compared to SKT candidates. Explained by longer operative procedures and anesthetic time in addition to older recipients.
– In EBK, vascular complications were due to smaller vessels
Well done as usual
Of course renal transplantation either from living or deceased donor is the best option and solution for CKD stage 5 on dialysis, as the dialysis is associated with increased morbidity and mortality, also it cost is higher than the cost of transplantation so it has financial burden on the government and also psychological burden on the patients themselves.
The number of patients on dialysis increasing every year because of increased incidence of diabetes, hypertension and obesity, and this is not matched with availability of transplantation as a solution to improve quality of life because of lack of donors, so the only option in that context to expand the donor pool to increase number of transplanted patients to match the rise in the numbers of patients being on dialysis and to decrease the waiting time staying on dialysis and shorten the transplant waiting list.
Many options brought to expand the donor pool like deceased kidney donor with expanded criteria like old age donor, donation after cardiac death, history of hypertension or diabetes or even acute renal impairment like AKI acute kidney injury.
The recipient, who received such ECD expanded criteria donor mostly old age, has low immunological profile, patient with running out vascular access, and small size patient like female or small size male.
These criteria of ECD yields suboptimal graft function and outcome, more DGF delayed graft function and more PNF primary nonfunctioning graft, so to increase the nephron mass to improve GFR to make the patient dialysis independent and to improve graft outcome and graft and patient survival , we can do DKT dual kidney transplant means transplanting both donor kidneys in a single recipient and this approach has more than one technique.
Biopsy can be done for the kidney donor pre-transplant to decide whether discarding or not the kidney donor based on the scoring system called Remuzzi score depends on the percent of glomeulosclerosis, tubular atrophy , interstitial fibrosis and vascular changes like arterial or arteriolar narrowing, this also will help to make a decision for DKT.
DKT can be done on both sides or transplanted unilateral as both kidneys were put in one side right kidney lying superior to the left kidney with anastomosis of renal artery to common iliac artery and renal vein to inferior vena cava and left kidney renal artery and vein anastomosed to external renal artery and vein, both right and left ureters are joined together then anastomosed to the urinary bladder, this technique is better than bilateral transplant both kidneys as it has lower surgical complications, lesser operative time.
Complications can happen like bleeding, graft thrombosis , renal vein or artery thrombosis, urinary fistula, also DKD for pediatric kidneys is associated with higher thrombotic complications because of small size vessels.
What are the the other simpler ways to help choose SKT or DKT ,you can find in the article
This is a narrative review study discussing the importance and impact of double kidney transplantation and comparing several articles showing their experiences.
With the extended criteria donor concept established by UNOS in 2003, the availability of organs has increased, but often with a marginal response and smaller renal masses. Added to this is the concept of cardiovascular deceased donors, increasing warm ischemia time. In this context of criteria that increase the risk of late graft response, there was the idea of increasing kidney mass by providing two instead of one kidney from the same donor.
DKT has a higher risk of surgical complications due to the high warm ischemia time added to a greater number of anastomoses and tissue injuries, being twice as risky as SKT.
Johnson et al used donors older than 60 years with a history of SAH or DM with cold ischemia time of fewer than 30 hours. CrCl between 80 and 40mL/min and less than 40% glomerulosclerosis with 100% six-month survival.
Remuzzi et al established histopathological criteria in patients over 60 years of age, diabetic, and with proteinuria less than 3g in 24h, excluding patients with insufficient biopsies (< 25 glomeruli) or signs of organ ischemia. 100% survival at six months.
Andres et al considered patients over 75 years of age or between 60 and 75 years of age with 15-50% glomerulosclerosis. Six-month graft survival was 95%.
UNOS considered over 60 years of age, CrCl > 65mL/min, creatinine above 2.5mg/dL, chronic SAH or DM2 with glomerulosclerosis between 15-50%. Three-year survival was 79.8%.
Ekser et al considered donor age, and clinical and histopathological findings. The three-year graft survival was 90.9%.
Snanoujd et al considered CrCl < 30mL/min discarding the organ, above 60mL/min performing SKT, and between these values DKT with graft survival in two years of 90%.
United Kingdom suggested that donors over 70 years old with at least one risk factor: SAH, AMI, DM 2, cardiovascular death, serum creatinine above 2, and presence of a renal anatomic anomaly. In addition, prolonged warm ischemia time and small kidneys must be considered.
In pediatric patients, there is a great anatomical challenge (high risk of thrombosis and vascular lesions) as well as the match between age, weight, and immunological context.
To minimize low renal mass, it is preferable to make these organs available to patients with low immunological risk, younger than 60 years, and with a BMI less than 30. Weight and height should be considered.
The surgical technique is a challenge, as one kidney on each side increases the surgical time and the trauma area, compromising the patient’s warm ischemia time and perioperative recovery. Even when establishing unilateral deployment, several techniques have been established to minimize the risks discussed above.
Studies by Lee, UNOS, D Arcy, and Snanoujd reiterated the groups with the greatest advantage for DKT, with good results in three years. Tanriover places DKT with OR 0.76 when compared to SKT in ECD patients. In fact, DKT decreased the discard rate of organs that would be submitted to SKT by three times.
Complications are related to greater surgical trauma, greater risk of thrombosis, vascular injuries, leakage of anastomoses, increased warm ischemia time, ureteral stenosis, urinary fistula, recurrent urinary tract infection, and the need for an intensive care unit. But the positive impact of performing DKT in patients with ECD or suboptimal renal function is undeniable.
Excellent Thankyou
Dual Kidney Transplant.
Introduction.
One of the ways to increase donor pool is to increase the number of organs available for transplant, the use of kidneys from donors from age extremes (pediatric or elderly) , and using donors older than 60 years or those who are older than 50 with a history of hypertension, had cause of death due to cerebrovascular events, or have serum creatinine level at retrieval of more than 1.97 mg/dL which they called ECD and also DCD but using kidney with marginal criteria has high risk of mal-functioning graft due to decreased nephron mass therefore dual kidney transplantation has been adopted but still there are some limitations as surgical and vascular complications and poor graft outcome.
which kidney is suitable for dual transplant?
No global consensus regarding criteria for DKT but each center has his own experience but UNOS database published on 2008,about 525 DKT from 2000 to 2005, they were considering DKT if two criteria fulfilled from these criteria :
1-age greater than 60 years.
2-Creatinine clearance greater than 65 mL/min.
3-Rising serum creatinine greater than 2.5 mg/dL at retrieval.
4-Chronic hypertension or type 2 diabetes mellitus.
5-glomerulosclerosis on biopsy between 15% and 50%.
We can avoid biopsy based decision depending on e GFR ,donors with eGFR > 60 mL/min were considered for SKT. Kidneys were discarded when eGFR was < 30 mL/min, and eGFR between these results was an indicator for DKT.
United Kingdom Kidney Advisory Group: kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of hypertension, myocardial infarction, type 2 diabetes mellitus, cerebrovascular event as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (renal artery stenosis, polycystic, small kidneys).
Sheffield center:
uses this approach. Kidneys with prolonged warm ischemia time, small kidneys, eGFR < 60 mL/min, kidneys with multiple cysts, and kidneys from elderly donors (> 70 y) are considered for DKTs, especially in association with donors who have a history of hypertension or type 2 diabetes mellitus.
who is a suitable recipient?
Better thing to match the recipient regarding age and size as older recipient can tolerate nephron mass and expected life time and better to be low immunological risk as recipients without previous transplant and panel reactive antibody titer < 50% to avoid over immunosuppression and attacks of rejections.
Sheffield center: prefers offering DKTs to patients with low immunological risk, who are less than 60 years old, and who have minimal comorbidities and body mass index < 30 kg/m2.
Surgical technique.
Transplanting 1 kidney to each side was the first approach and had more tissue dissection and a longer operative time.
A midline extra peritoneal approach characterized by a shorter operative time and dissection and fewer hernia complications.
Unilateral placement of both kidneys reduced trauma from the surgical procedure and operative time. Moreover, the contralateral side remained untouched for possible future transplant which is the preferred technique in most centers .
To avoid vascular complications in pediatric DKT, En block kidney transplant using pediatric donor aorta and the inferior vena cava can theoretically reduce that risk.
Graft and patient survival.
Studies shown that recipients of DKT had better graft function than both control groups (recipients of SKT from donors > 60 y or from donors < 50 y but the follow up period was short.
Lee and associates reported similar patient and graft survival at 1 year and 2 years between DKT and SKT.
UNOS database shown that recipients of DKTs from ECDs had similar death-censored graft survival and also showed that 77% of EBKs were from donors < 5 years old, graft survival at 1, 3, and 5 years was superior (85%, 76%, 71%) versus SKT.
The Newcastle team reported similar eGFR results at 3 and 12 months post-transplant in a comparison of DKT with donations after cardiac death versus SKT.
Proteinuria was slightly increased during follow-up. Of note, the pediatric kidneys grew to approach adult kidney size in the first months due to increasing nephron mass and risk of sclerosis.
Complications.
Local wound dehiscence which is now low with new techniques.
Early renal graft thrombosis & vascular thrombosis.
Urinary tract complications(fistulae, stenosis).
Myocardial infarctions when compared to SKT candidates due to longer operative procedure and anesthetic time.
Conclusions.
Dual kidney transplant allocation criteria still need more randomized control studies to give us consensus in selection the donors and recipients because it considered a great source of donation from marginal kidneys and has same graft and patient survival as SKT, Ipsilateral placement of both grafts is widely accepted and performed approach with less surgical and vascular complications.
Well done very comprehensively summarized
Please provide a summary of this article
Introduction
To increase the number of donor pool, DKT from marginal kidneys are used (ECD and DCD) to maximize nephron mass
Many centers discard DKT as there in no clear guidelines, lack of experience and higher risk of surgical complications
Which kidney is suitable for dual transplant?
There are no guidelines to determine which kidney is suitable for DKT as there is no experience
Donor age, clinical risk factors and histology may be the most important factors
Donors with eGFR > 60 mL/min is considered for SKT, discard when eGFR < 30 mL/min, and eGFR between these results is for DKT
For biopsy score, 0-3 score or SKT, 4-6 for DKT, and discard if score is 7-12
The United Kingdom Kidney Advisory Group suggested that kidneys from donors who are age 70 years or older could be used for DKTs if 1 or more of the following clinical risk factors were present: history of HTN, MI, type 2 DM, CVA as cause of death, serum creatinine level of > 1.97 mg/dL at retrieval, or presence of any anatomic anomaly (RAS,APKD, small kidneys)
Histology is according to Remuzzi score of pretransplant biobsy (Glomerular global Sclerosis, tubular Atrophy, interstitial Fibrosis, and arterial and arteriolar narrowing)
Who is a suitable recipient?
The best candidate for DKT is not known
Suitable may be may be older recipients (older for older), recipient size and lower immunologic risk
Surgical technique
Unilateral placement of both kidneys through midline infraumbilical incision (extraperitoneal approach). This leads to shorter operative time and the graft survival at 1 year is similar to the bilateral technique
Outcomes and surgical complications were similar to SKT
Graft and patient survival
Patient and graft survival are comparable to SKT in most studies
In one study (Lee and associates), patient and graft survival at 1 year were (98% and 89% in DKT vs 97% and 90% in SKT) and 2 years (86% and 77% in DKT vs 95% and 86% in SKT).
Factors affect graft function are donor factors, donation circumstances, cold ischemia time, and perioperative events
En block kidney transplant was associated with slightly increased risk of graft loss when compared to SKTs
Complications
Complications are usually higher due to technical difficulties (long surgery time)
The most worrying complication is the early graft thrombosis
Other complications are wound dehiscence, urinary tract fistulas, higher risk of postoperative MI, and higher postoperative admission to ICU
According to a larger study, no difference in complications between ipsilateral DKT and SKT
EBK has a higher complication rate when compared to SKT
limitations of the study: level 5 study and limited cases in many centers
Conclusions
The outcomes of ipsilateral DKT are comparable to SKT
Despite the higher surgical complications, the outcome of an en block technique used in pediatric kidneys is the same
Further studies are required to determine which kidney is more suitable as DKT or SKT and to standardize criteria for DKT kidney allocation
Well done,