5. A 47-year-old male is keen to donate a kidney to his brother, 000 mismatch, no DSA and FCXM is negative. Excellent kidney function. He gave a past history Roux en Y gastric bypass for morbid obesity 7 years ago. His current BMI is 32. He also passed a small stone 5 years ago, never recurred. CT KUB is normal.
- How do you manage this case?
- What is the long-term outcome of kidney donation?
- Please substantiate your answer
Pt cannot be accepted for kidney donation
as he is still Obese despite bypass surgery
regarding the stone :should do work up to exclude recurrent stone formation like hyperoxaluria
this patient has the following risk factors for donation
1- obesity inspite of the surgery which signify his compliance with eating habits. he will be having high risk for hypertension after donation.
2- underwent Roux en Y gastric bypass hence prone for oxalate stones .I will not accept him as a donor as he has a risk of forming stones.
This potential donor has 3 Main risk factors :
1st obesity (moderate obesity) with high risk of perioperative complications and risk of metabolic syndrome
2nd is RYGB operation which has short term surgical complications and long term complications especially hyperoxaluria which may cause oxalate stones
3rd is previous history of passing small kidney stones which is in itself , not a contraindication for Transplantation.
So from the above mentioned risks , this donor should be discarded despite being immunogical good match .
this donor has many risk for renal disease:
1- BMI 32 ( FSGS)
2- past history Roux en Y gastric bypass3- H/O pass small stone
can has recurrent stone
because of the above, this donor has high risk of renal disease so I will not accept him for donation
He is not accepted as a donor due to following issues:
Long-term consequences of kidney donation in such patients(1):
He should be counselled for
Reference:
47 years old male patient has main 3 problems
moderate obesity BMI 32
history of Roux en Y bypass 7 years back
history of stone 5 years back (2 years post-operative).
Roux en Y bypass is associated with an increased risk of 2ry hyperostosis and nephrolithiasis which already occurred 2 years post-operative that’s why the patient is at high risk of recurrence even with a normal metabolic profile
this patient is at high risk of nephrolithiasis and renal disease
as regards a potential kidney being a healthy person with a low risk of developing chronic kidney disease I will decline this patient as a potential donor.
References:
1) Lentine KL, Kasiske BL, Levey AS, Adams PL, Alberú J, Bakr MA, Gallon L, Garvey CA, Guleria S, Li PK, Segev DL, Taler SJ, Tanabe K, Wright L, Zeier MG, Cheung M, Garg AX. KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors. Transplantation. 2017 Aug;101(8S Suppl 1):S1-S109. doi: 10.1097/TP.0000000000001769. PMID: 28742762; PMCID: PMC5540357.
2) British Transplantation Society. Renal Association Guidelines for Living Donor Kidney Transplantation, 4th ed.; British Transplantation Society: Macclesfield, UK, 2018; Available online: https//bts.org.uk/wp-content/uploads/2018/07/FINAL_LDKT-guidelines_June-2018.pdf (accessed on 3 October 2022).
3) Praga M, Hernández E, Herrero JC, Morales E, Revilla Y, Díaz-González R, Rodicio JL. Influence of obesity on the appearance of proteinuria and renal insufficiency after unilateral nephrectomy. Kidney Int. 2000 Nov;58(5):2111-8. doi: 10.1111/j.1523-1755.2000.00384.x. PMID: 11044232.
4) Lim R, Beekley A, Johnson DC, Davis KA. Early and late complications of bariatric operation. Trauma Surg Acute Care Open. 2018 Oct 9;3(1):e000219. doi: 10.1136/tsaco-2018-000219. PMID: 30402562; PMCID: PMC6203132.
5) Chang AR, Grams ME, Navaneethan SD. Bariatric Surgery and Kidney-Related Outcomes. Kidney Int Rep. 2017 Mar;2(2):261-270. doi: 10.1016/j.ekir.2017.01.010. Epub 2017 Jan 26. PMID: 28439568; PMCID: PMC5399773.
6) Carbone A, Al Salhi Y, Tasca A, Palleschi G, Fuschi A, De Nunzio C, Bozzini G, Mazzaferro S, Pastore AL. Obesity and kidney stone disease: a systematic review. Minerva Urol Nefrol. 2018 Aug;70(4):393-400. doi: 10.23736/S0393-2249.18.03113-2. Epub 2018 May 31. PMID: 29856171.
7) Espino-Grosso PM, Canales BK. Kidney Stones After Bariatric Surgery: Risk Assessment and Mitigation. Bariatr Surg Pract Patient Care. 2017 Mar 1;12(1):3-9. doi: 10.1089/bari.2016.0048. PMID: 28465866; PMCID: PMC5361755.
47-year-old male his main risk factors are: Obesity, stone history and previous bariatric surgery.
According to BTS:
Ø Moderately obese patients (BMI 30-35 kg/m2) must undergo careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease.
Ø Must be counselled about the increased risk of peri-operative complications based on extrapolation of outcome data from very obese donors (BMI >35 kg/m2).
Ø Must be counselled about the long-term risk of kidney disease and be advised to lose weight before donation and to maintain their ideal weight following donation
Ø Adding the risk of Roux en Y gastric bypass surgery and stone passage. He need detailed medical and dietary history, serum chemistries and urinalysis. Metabolic testing of one or two 24-hour urine collections obtained on a random diet and analyzed at minimum for total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium and creatinine.
Ø Overweight and obese individuals are at increased risk of hypertension, hypercholesterolemia, insulin resistance and diabetes, heart disease, stroke, sleep apnoea and certain cancers.
What is the long-term outcome of kidney donation?
Ø Increase in peri-operative complications
Ø Focal glomerulosclerosis and obesity-related glomerulopathy
Ø Recurrence of stone
Reference:
BTS/RA Living Donor Kidney Transplantation Guidelines 2018
Montgomery JR, Telem DA, Waits SA. Bariatric surgery for prospective living kidney donors with obesity? Am J Transplant. 2019 Sep;19(9):2415-2420. doi: 10.1111/ajt.15260. Epub 2019 Feb 19. PMID: 30632698.
Kidney donation after bariatric surgery needs more evaluation. This donor is moderately obese (BMI:32) with an increased risk of cardiovascular, respiratory (sleep apnea) and kidney disease. After bariatric surgery, risk of renal stones is increased related to bile malabsorption which leads to secondary hyperoxaluria, hypovolemia, hyperuricosuria (he still has metabolic syndrome), risks of adhesions and re-operation and so on. He should receive plenty of fluid intake, low sodium and oxalate diet and high calcium intake after donation. After determining other cardiovascular risk factors like hypertension, hyperlipidemia or diabetes, which they should be controlled, too.
Long term outcome:
Locke showed higher risk of CKD for obese donors. Obese donors have more surgical complications such as wound dehiscence, bleeding, adhesions, and post-surgical hernia.
Considering these conditions, even though he has not an absolute contraindication, it is better for him not to be a donor.
Nalesnik MA, Woodle ES, Dimaio JM, Vasudev B, Teperman LW, Covington S, Taranto S, Gockerman JP, Shapiro R, Sharma V, Swinnen LJ, Yoshida A, Ison MG. Donor-transmitted malignancies in organ transplantation: assessment of clinical risk. Am J Transplant. 2011 Jun;11(6):1140-7.
How do you manage this case?
What is the long-term outcome of kidney donation?
Please substantiate your answer
47 y old male potential donor for his brother with low immunologic risk offer including 000 mismatch, absent DSA, and negative flowcytometry. However, this potential donor is moderately obese with BMI 32 with history of gastric bypass surgery 7 years ago and passing a small renal stone 5 years ago.
Proper pre-donation counselling is important especially regarding:
1- higher risk of peri-operative complications in obese donors.
2- High BMI is a risk factor for DM, HTN and CKD in patients with solitary kidney.
3- High BMI is a risk factor for proteinuria especially post donation.
RYGB bypass surgery is associated with the following long-term complications:
1- GB stones.
2- Malignant ulceration.
3- Internal Hernia and intussception.
4- Peri-operative AKI, renal stones and oxalate nephropathy.
5- Steatorrhea, enteric hyperoxaluria, increased oxalate absorption and oxalate renal disease.
This potential donor should have CT-KUB done to make sure that there is no stones, and should have stone work up like urinary collection for stone work up including (citrate, oxalate, urate, Mg, Na, K, PH).
I would not accept this donor because of potential risks.
He should be conselled regarding his high BMI and advised for healthy life style including low oxalate low salt low fat diet, exercise, fluid intake
Regarding the obesity:
The BMI is 32, considered moderate obesity and is associated with increased morbidity as increased risk of HTN, DM, hypercholesterolemia and cardiovascular complications.
Obesity also is associated with increased risk of perioperative complications and delayed wound healing.
Regarding the stone:
The donor has history of single stone with no history of recurrence and normal CTUT, metabolic screen should be done and if there is significant metabolic abnormality detected, the donor will be declined.
Our donor may be accepted for donation if there is no other donor available for donation.
He should be counselled about the importance of maintaining ideal weight after donation and the need for follow up of kidney functions after donation as well as blood pressure, proteinuria and blood glucose
The long term outcome:
Increased risk of renal stone formation
Obesity associated comorbidities as HTN
obesity related FSGS
BTS/RA Living Donor Kidney Transplantation Guidelines 2018
How do you manage this case?
Comorbidities:
· Post bariatric surgery which is associated with hyperoxaluria and increased risk of kidney stones due to high urinary calcium oxalate, low urine citrate, and low urine volume. Despite absence of current stones in CT, the history of previous stone disease indicates his underlying metabolic disturbance and increased risk of stone formation in the future
· Grade 1 obesity increases the risk for development of DM , HTN ,obesity related glomerulopathy and seconadary FSGS
Management:
· Reduce the risk of hyperoxaluria and stone formation by encouraging for more fluid intake, reduce dietary oxalate and sodium intake and calcium rich food. Also, go for metabolic work up and 24 hr stone panel beside following renal functions
· For obesity, encourage weight loss, exercise program and screen for cardiovascular risk factors
What is the long-term outcome of kidney donation?
· Bariatric surgery increases the risk of secondary hyperoxaluria that may result in stone formation and this may affect the remaining kidney after donation.
· Moderate obesity is associated with increased risk for perioperative complications after kidney donation
Please substantiate your answer
· This donor should be declined in view of the previously metioned comorbidities unless no other donors are available.
· An MDT approach and full explanation for both the donor and the recipient about the risks for donation.
· If no other donors are available and the donor is quite willing to donate:
1. Encourage the donor for weight reduction, regular exercise and life style modification to reduce the incidence of CV risk factors
2. Reduce the incidence of hyperoxaluria and stone formation by increasing fluid intake, increase oral calcium to chelate oxalate and use K citrate to alkalinize the urine and prevent stone formation
3. Provide full explanation for the donor and the recipient about the possible future problems with this donation and obtain informed consent
References:
1- BTS/RA Living Donor Kidney Transplantation Guidelines 2018
2-Upala S, Jaruvongvanich V, Sanguankeo A. Risk of nephrolithiasis, hyperoxaluria, and calcium oxalate super-saturation increased after Roux-en-Y gastric bypass surgery: a systematic review and meta-analysis. Surg Obes Relat Dis. 2016;12(8):1513-1521.
This male candidate donor, 47 year old, with history of morbid obesity, Roux en Y operation 7 years ago, history of stone formation and passage 5 years ago, current BMI: 32, cannot be allowed for donation owing to the following:
Morbid obesity is associated with metabolic syndrome worldwide with high incidence of HTN ,DM ,prediabetes , obstructive sleep apnea , accelerated atherosclerosis ,cardiovascular events ,renal affection could also result due to development of FSGS ,adding on this this bariatric surgery operation possibly leads to secondary hyperoxaluria ,subsequent renal stones formation, disrupted metabolic profile , dehydration states ,multivitamin deficiency ,yet still his BMI is too high poses him to subsequent surgical complications in the perioperative period ( difficulty retrieval of the kidney ,injury to abdominal organs and nearby tissues, delayed wound healing ,wound infections ,difficulty mobilization after the opera ration ,thromboembolic events as well) .
The long-term outcome for renal donation for him is hazardous ,according to studies patients with known morbid obesity is more liable to suffer renal impairment and CKD by various aetiologies as hyperfiltration pressure injury and FSGS,also the risk of comorbid conditions that would probably result from obesity as uncontrolled HTN ,DM ,OSA, in addition to tendency of renal stone formation after Roux en Y procedures adding to this all the metabolic derangement .
This donor to be frankly counselled with all the previous risks to be highlighted .he is not allowed to donate unless:
Weight control to achieve BMI below 30.
Metabolic workup to be negative.
Cardiology examination with detailed investigations to rule out any cardiac risk.
Endocrinologist and diabetologist with intact HBA1c, OGTT, fasting and post prandial blood sugar.
Respiratory functions and chest medicine approval for donation.
Dietician should be counselled as well for proper management of nutritional derangement after Roux en Y procedures and the use of on demand supplements according to his needs.
This is according to the KDIGO and British Transplantation Society guidelines, with frequent close monitoring for such donors for weight gain, glycemic control, smoking cessation, high fluid intake, exclusion of renal stones, metabolic work up and renal functions.
Currently could not donate, because history of stone disease and future risk of stone formation(oxalate over absorption).
moderately high BMI,
So there will be perioperative complication, wound dehiscence, infection, delayed healing, long term complication would be hypertension, DM, stone disease, OSA, needed high drug( level) level, FSGS.
BTS 2018, KDIGO.
1) Not to proceed with kidney donation at this moment.
2) MDT meeting for patient progress post gastric bypass surgery. BMI reduction trend. Cardiovascular assessment by cardiologist, assessment of possible etiology for renal stone, screening for UTI, screening for metabolic disorder eg DM, hyperlipidemia by endocrinologist. Respiratory function assessment / Sleep study by respiratory physician exclude OSA.
What is the long-term outcome of kidney donation?
Obesity associated co-morbidities such as hypertension, diabetes and the metabolic syndrome may compromise future kidney function. Obesity is associated with FSGS which 25% may lead to ESRD.
British Transplant Association 2018
Recommendations
1) Otherwise healthy overweight patients (BMI 25-30 kg/m2 ) may safely proceed to kidney donation.
2) Moderately obese patients (BMI 30-35 kg/m2 ) must undergo careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease
This potential donor although have a good immunological match but he is not suitable for donation and will be declined by most centers.
-Most centers avoid donations from individuals with BMI above 35 kg/m2 .
His BMI is 32 so he is grade 2 Obesity according to World Health Organization (WHO) definition and classification of obesity
some centers use lower limits for BMI for younger donors and there is some variability in the upper limit by center.
-Obesity has greater operative complication and is a risk factor for the development of type 2 diabetes mellitus and diabetic kidney disease.
-Obesity is also associated with hyperfiltration and may lead to obesity related glomerulopathy although not common.
-potential donor with obesity may be at greater risk for cardiovascular disease such as hypertension, elevated cholesterol and triglyceride levels.
UNOS recommends that potential donors with multiple metabolic abnormalities must be carefully evaluated for their potential risk for cardiovascular complications at the time of or after donor surgery. If that risk is felt to be too high, the donor would be excluded from donation.
-weight loss procedures cause high urine oxalate levels related to food malabsorption that may increase the risk for kidney stones.
Individuals who have undergone a surgical procedure (gastric bypass or gastric sleeve) may require additional testing of oxalate metabolism in order to be considered as donors and may be excluded at some centers even if oxalate metabolism is normal.
– patient already had a stone 2 years after Roux en Y gastric bypass ,incidence of recurrence of renal stones is high and full metabolic work up and follow-up is required.
Taler.The Obese Kidney Donor.Living Donor Community of Practice of AST.
This potential donor is unfit for transplantation due :
thanks
· RYGB has been linked to metabolic changes that could alter urine chemistry profiles, resulting in both higher calcium oxalate supersaturation and urine oxalate, lower citrate, and lower volume.
· So, patients have a higher risk of developing nephrolithiasis after RYGB
· While uncommon, increased absorption of calcium oxalate could also lead to deposition in the renal parenchyma, resulting in oxalate nephropathy and renal failure
· A retrospective review of 11 patients with oxalate nephropathy found that all were hypertensive and nine were diabetic before the procedure
To conclude, the donor with history of post RYGB, has high risk of acute and chronic kidney disease, and should be excluded from donation
1)https://pubmed.ncbi.nlm.nih.gov/27396545/#:~:text=Risk%20of%20nephrolithiasis%2C%20hyperoxaluria%2C%20and%20calcium%20oxalate%20supersaturation%20increased%20after%20Roux%2Den%2DY%20gastric%20bypass%20surgery%3A%20a%20systematic%20review%20and%20meta%2Danalysis
2)https://pubmed.ncbi.nlm.nih.gov/27692909/#:~:text=Oxalate%20mediated%20renal%20complications%20after%20Roux%2Den%2DY%20gastric%20bypass%3A%20weighing%20the%20risks%20versus%20benefits
3)://pubmed.ncbi.nlm.nih.gov/18701613/#:~:text=Oxalate%20nephropathy%20complicating%20Roux%2Den%2DY%20Gastric%20Bypass%3A%20an%20underrecognized%20cause%20of%20irreversible%20renal%20failure
There are multiple issues in this donor to be analyzed
Although the donor is a perfect immunological match for his brother, we should counsel the patient against kidney donation in this case
The patient has morbid obesity and has undergone bariatric surgery for the same 7 years ago…The weight loss journey after bariatric surgery is slow in the initial 1 or 2 years after surgery and it proceeds to have a weight loss of 20 – 30% after 2 or 3 years…Diet restriction often needs to be maintained after surgery.. It is surprising that the current BMI is 32 which is very much in the obese category….Obesity has surgical difficulties in laproscopic nephrectomy..There could be increased chances of wound infections in the post operative period and long term risk of incisional hernia is there…10 years after nephrectomy those patients with obesity (BMI>30 kg/m2) nearly 60% of them develop proteinuria and 20% have developed renal insufficiency …So obesity itself has poor long term consequences after kidney donation…
This patient also had features of secondary oxalosis after Roux-En Y Bypass surgery…This surgery leads to increased oxalate absorption and can cause nephrolithiasis and oxalate nephropathy itself….The patient has passed a small stone 2 years after the bariatric surgery and this will need urinary and serum oxalate assessment with urine pH and urine calcium and urine citrate analysis..The donor should be counselled about the lifetime recurrence of stone about 30 to 50% depending on the size of the stone ….
So based on the above two factors he is not a suitable donor
The Roux-en-Y gastric bypass is considered the gold-standard weight loss operation as it has proven successful at durable weight reduction and reversal of obesity-associated comorbidities.
Due to its malabsorptive nature, the Roux-en-Y gastric bypass is, however, associated with the potential for long-term nutritional and metabolic derangements. In the particular context of kidney donation, these metabolic derangements can alter the urinary milieu, leading to an approximately twofold increased risk of calcium oxalate nephrolithiasis and the rare possibility of developing oxalate nephropathy.
For this potential donor:
His BMI is 32, and this required intensive investigations before accepting him as a donor, including CV evaluation, DM, Hyperuricemia, and evaluation for ca oxalate stone risk.
The potential donor needs to be informed about the perioperative risk, maintaining weight loss and dietary restrictions to avoid hyperoxaluria.
Reference:
Nguyen MJP, Carpenter D, Tadros J, Mathur A, Sandoval PR, Woodle ES, et al. Bariatric surgery prior to living donor nephrectomy: a solution to expand the living donor kidney pool–a retrospective study. Transplant International. 2019; 32: 702–709.
As regard to his obesity:
He has moderate obesity which means more perioperative complication and inferior long term outcomes
Need through assessment for cardiovascular, dyslipidemia and counselling about risk for developing proteinuria and FSGS after donation.
As regards passing stone once 2 years after bypass surgery
Stone formation could complicate bariatric surgery:
De novo hyperoxaluria complicates 50% of RYGB operation
-Due to decrease fat absorption leading to an increase unbounded oxalate and oxalate stone formation, increased oxalate permeability after increase unconjugated bile salts
– stone formation starts 1.5-2 years after operation and still up to 10 years after the operation.
So, I could not accept him as a donor
references:
1- Tarplin S, Ganesan V, Monga M. Stone formation and management after bariatric surgery. nature reviews 2015
2-Nelson, W. K., Houghton, S. G., Milliner, D. S.,Lieske, J. C. & Sarr, M. G. Enteric hyperoxaluria, nephrolithiasis, and oxalate nephropathy: potentially serious and unappreciated complications of Roux‑en‑Y gastric bypass. Surg. Obes. Relat. Dis. 1, 481–485 (2005).
3- Lieske, J. C. et al. Kidney stones are common after bariatric surgery. Kidney Int. http:// dx.doi.org/10.1038/ki.2014.352
4- BTS/RA Living Donor Kidney Transplantation Guidelines 2018.
Although bariatric surgery is associated with improvements in metabolic outcomes, malabsorptive bariatric surgery procedures are also associated with increased risk of kidney stones. Restrictive bariatric surgeries have not been associated with kidney-stone risk. Higher risk of kidney stones after malabsorptive procedures is associated with postsurgical changes in urine composition, including high urine oxalate, low urine citrate, and low urine volume. Certain dietary recommendations after surgery may help mitigate these urine changes and reduce risk of kidney stones. Understanding risk of kidney stones after surgery is essential to improving patient outcomes afer bariatric surgery surgery
this pateint investigate for other CVS risk factor such as DM ,HTN and lipid profile to avoid cvs event and postoperative complication
reference
risk Factors for Kidney Stone Formation following Bariatric Surgery:Megan Prochaska and Elaine Worcester Kidney360 December 2020, 1 (12) 1456-1461; DOI:
Kidney transplantation for this recipient has chance for the best allograft and survival rate from the immunological point of view. Despite that, donation can be associated with post-donation complications due to bariatric surgery and BMI of 32.
Metabolic syndrome lab work up includes : BP check and for DM &dyslipidemia .Obesity is associated with postsurgical complications and higher incidence of cardiovascular sequalae.
Even without detected metabolic disorders, patient should be advised a life style modification ;diet and exercise, for weight reduction and combating related complications.
RYGB is associated with long term stone formation especially of calcium oxalate stones and nephrocalcinosis. The patient has history of small stone 5 years ago and is at risk of recurrent stone formation.
As the potential donor has best immunological match, he should reduce his BMI to 20-25 –, intensive metabolic workup including urine collection to test for hypocitraturia/hyperoxaluria to lower risk of stone formation .Vitamin 6 and citrate supplementation could be needed.
BTS guidelines,2018
*This 47 year male with low immunological risk, 0-0-0 mismatch, no DSA, and negative FCXM, and excellent kidney function, had past history of Roux en Y gastric by pass for mobid obesity, 7 years ago, his current BMI is 32 and he passed a small stone 5 years ago, never recurred . CT KUB is normal. *According to BTS/RA Living Donor Kidney Transplantation Guidelines 2018.
Otherwise healthy overweight patients (BMI 25-30 kg/m2) may safely proceed to kidney donation. (B1)
Moderately obese patients (BMI 30-35 kg/m2) must undergo careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease. (C2)
Moderately obese patients (BMI 30-35 kg/m2) must be counseled about the increased risk of peri-operative complications based on extrapolation of outcome data from very obese donors (BMI >35 kg/m2).(B1)
Moderately obese patients (BMI 30-35 kg/m2) must be counselled about the long-term risk of kidney disease and be advised to lose weight before donation and to maintain their ideal weight following donation. (B1)
Data on the safety of kidney donation in the very obese (BMI >35 kg/m2) are limited and donation should be discouraged. (C1)
Obese individuals are at increased risk of hypertension, hypercholesterolemia, insulin resistance and diabetes, heart disease, stroke, sleep apnoea and certain cancers (3).
Obesity is considered a relative contra-indication to living kidney donation because of the increased risk of surgical complications and the adverse impact of obesity on renal function in the longer term.
*In the absence of a significant metabolic abnormality, potential donors with a limited history of previous kidney stones, or small renal stone(s) on imaging, may still be considered as potential kidney donors. Full counselling of donor and recipient is required along with access to appropriate long-term donor follow up. (C2)
Potential donors with metabolic abnormalities detected on screening should be discussed with a specialist in renal stone disease. (C2)
In appropriate donors with unilateral kidney stone(s) the stone-bearing kidney can be considered for donation (if vascular anatomy and split kidney function permit) in order to leave the donor with a stone-free kidney after donation. (C2)
the risks of recurrent stone formation are low in asymptomatic potential kidney donors. However, in the absence of a reliable evidence base, a degree of caution is warranted.
*After bariatric surgery, patients have an increased risk for kidney stones.
Research shows that gastric bypass patients have changes in urine and higher levels of particles, called oxalates, which form kidney stones. You see, the gastrointestinal (GI) tract naturally absorbs oxalate. However, once the GI tract is altered during surgery, higher levels of oxalate can occur in the urinary tract. The oxalate can form crystals, which may lead to the formation of kidney stones.
*There are ways to prevent kidney stones from forming.
Drink alots of water.
Reduce sodium intake.
Limit oxalate containing food.
BTS/RA Living Donor Kidney Transplantation Guidelines 2018.
This potential kidney donor has obesity despite gastric bypass surgery 7years before, Also, had history of passing stone 5years before. From above mentioned history he is not good candidate for donation. As he has moderate obesity plus history of renal stone plus diabetes. This is stated clearly in BTS guidelines: moderately obese patients (BMI 30-35 kg/m2) must undergo careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease. (C2) Moderately obese patients (BMI 30-35 kg/m2) must be counselled about the increased risk of peri-operative complications-based extrapolation of outcome data from very obese donors (BMI >35 kg/m2). (B1)
Moderately obese patients (BMI 30-35 kg/m2) must be counselled about
the long-term risk of kidney disease and be advised to lose weight before donation and to maintain their ideal weight following donation.
Increased risk of peri operative complications, hypertension, proteinuria and renal failure. Also because of his history of bariatric surgery he has increased risk of renal stone.
BTS guidelines 2018
He is moderately obese as his BMI is 32 ((BMI 30-35 kg/m2). He should be informed about about the increased risk of peri-operative complications. He should have a careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease. He should be informed about the long-term risk of kidney disease and advised to lose weight before donation.
Overweight and obese individuals are at increased risk of hypertension, Hypercholesterolemia, diabetes, heart disease, sleep apnoea etc. .
This patient should be informed that he is at increased risk of surgical complications and the adverse impact of obesity on renal function. Obesity is associated with a higher risk of developing end stage kidney disease.
Patient with Roux Y gastric bypass (RYGB) have an increased calcium oxalate kidney-stone risk due to high CaOx SS from high urine oxalate, low urine citrate, and low urine volume. Roux gastric bypass is also associated with increased risk of dehydration and malnourishment
Therefore this patient should be advised a weight reduction (dietician referral) and metabolic screen in view of previous history of renal stones as he is at risk of nephrolityiasis. He will also need an MDT to discuss the suitability of this potential donor
As I mentioned above in terms of comorbidities, obesity is associated hypertension, diabetes, cardiovascular risk and metabolic syndrome which all of them may increase the risk of future renal impairment. He is also at increased risk of calcium oxalate kidney-stone in view of his gastric bypass (RYGB). He is also at higher risk of developing end stage kidney disease (obesity is independently associated with ESRF). Patient with obesity after neprectomy are also at increased risk of proteinuria and renal impairment.
References:
BTS/RA Living Donor Kidney Transplantation Guidelines 2018
Risk Factors for Kidney Stone Formation following Bariatric Surgery:Megan Prochaska and Elaine Worcester Kidney360 December 2020, 1 (12) 1456-1461; DOI:
The index donor is
000 mismatches.
no DSA Negative
flowcytometry
Moderate obesity with BMI 32
Past history ROUX EN Y gastric by pass 7 years ago.
History of passing small stone years ago with no history of recurrence and normal
CT
Obesity carry’s risk of dyslipideria, hypertension diabetes and cardiovascular diease
It may associated with nephrotic range posteinmia and subsequent FSGS carry bad
bad prognosis.
I will postpone this donor until patient reduce body weight with follow up by lab
Donor : 47 years ,he gave a past history Roux en Y gastric bypass for morbid obesity 7 years ago. His current BMI is 32. He also passed a small stone 5 years ago, never recurred. CT KUB is normal.According to kidney stone
there is history of passing small stone 5 years ago ,
in absence of a significant metabolic abnormality , potential donor with limited history of previous kidney stones may still be considered as potential donor.
According to obesity
body mass index is 32 which is moderate obese
moderately obese patients must undergo careful pre-operative evaluation to exclude cardiovascular, respiratory and kidney disease.
and must be counselled about the increased risk of peri-operative complications
and must be counselled about the long term risk of kidney disease and be advised to lose weight before donation.
overweight are at increased risk of hypertension , DM , insulin resistance , heart disease and stroke. higher risk of developing end stage renal disease
Focal glomerulosclerosis with associated proteinuria
peri-operative complications from minor ( wound complication ) to major ( conversion of laparoscopic to open nephrectomy)
Past history Roux en Y gastric bypassand its complications ( anastomotic stricture, marginal ulceration , gastro gastric fistula , cholelithiasis and nutritional complications ( B12, folate and thiamine )
I can accept him 000 mismatch
The first issue obesity
Recommendations of BTS/RA Living Donor Kidney Transplantation Guidelines 2018
overweight and obese individuals are at increased risk of hypertension, hypercholesterolemia, insulin resistance and diabetes, heart disease, stroke, sleep apnoea and certain cancers.
Obesity is considered a relative contra-indication to living kidney donation because of the increased risk of surgical complications and the adverse impact of obesity on renal function in the longer term.
obesity is independently associated with a higher risk of developing end stage kidney disease (11). Focal glomerulosclerosis and obesity-related glomerulopathy (glomerular enlargement and mesangial expansion) with associated proteinuria have been described in patients with severe obesity (12) and may be reversible with weight loss. Obesity is also a risk factor for renal insufficiency after unilateral nephrectomy.
The second issue RYGB, are associated with increased calcium oxalate kidney-stone risk. Higher kidney-stone risk after RYGB is related to high CaOx SS from high urine oxalate, low urine citrate, and low urine volume.
Common recommendations include a low-oxalate diet, timing calcium supplementation with meals, increased fluid intake, and possible citrate supplementation.
Third issue is hx of stone formation
All these issues making this donor till now not suitable enough for donation with high risk of future nepholithiasis formation
Substitute your answer
Risk Factors for Kidney Stone Formation following Bariatric Surgery
Megan Prochaska and Elaine Worcester
Kidney360 December 2020, 1 (12) 1456-1461; DOI: https://doi.org/10.34067/KID.0004982020
BTS/RA Living Donor Kidney Transplantation Guidelines 2018
This patient from immunological point of view has no immunological risk with low risk but the main issues came from:
1/ obesity with BMI of 32 which need to be discussed ,his past history of Roux v gastric bypass may increase the chance of metabolic derangement and further stone formation .
As we all know obesity with increased preoperative risk factors and increase morbidity post RTX with DM,,HTN, and CVD .
Roux gastric bypass associated with increase risk of dehydration and malnourishment .
Such donation need MDT to take the final decision of donation .
Obesity by it self is a relative contraindication for kidney donation.
It may predispose to many risk factors like HT, DM , hyperlipidemia , CVD and renal failure .
Obesity associated with hyperfiltration injury and proteinuria with secondary FSGS which can lead to ESRD.
Also obesity associated with peri operative complications like wound infection, wound dehiscence and hernias.
Obesity is also a risk factor for renal insufficiency after unilateral nephrectomy
In the other hand, hx of bariatric surgery increase the risk of malnutrition and metabolic abnormalities. It can lead to fat soluble vitamins deficiency and increase risk of calcium oxalate nephrolithiasis.
This donor must be precluded from donation because of high risk of recurrence stone and increase incidence of HT,DM , hyperlipidemia and peri operative complications.
If he is the only offer available so counseling him regarding the advers outcome after kidney donation in obese donor and advise him to decrease his weight and increase water intake and decrease protein and increase calcium in diet.
This 47-year- potential donor for his brother with 000 mis-match, no DSA and negative FCXM and normal kidney function. But with risk factors of obesity i.e., BMI 32 kg/m2 which is associated with both peri-operative and long term cardiovascular risks, also chances of kidney stones (uric acid with obesity) .Another major risk factor present is the past history of Roux en Y gastric bypass which causes nutritional and metabolic abnormalities and also increases the chances of recurrent stones especially oxalate stones due to 25% increase in urinary oxalate and 30 % decrease the urinary citrate .Considering all these risk factors ,it is better not to consider this patient for donation but if anted to consider then patient needs detailed metabolic profile evaluation and counseling for weight loss strategies and some dietary modification and explaining the risks in the long term of cardiovascular ,DM ,Hypertension and renal failure.
REFERENCES:
1-Nasr SH, D’Agati VD, Said SM, et al. Oxalate nephropathy complicating Roux-en-Y Gastric Bypass: an under-recognized cause of irreversible renal failure. Clin J Am Soc Nephrol. 2008;3(6):1676-1683.
2-BTS/RA Living Donor Kidney Transplantation Guidelines 2018
Immunologically, kidney transplant using the index prospective donor has low risk (in view of 000 mismatch, no DSA and negative FCXM).
But there are 3 important issues in this prospective donor
a) Moderate obesity (BMI 32)
b) A prior history of Roux en Y gastric bypass (RYGB)
c) A history of passing small stone
These issues are important and considering these issues, the donor should not be accepted.
There is increased risk of perioperative complications in obese individuals undergoing a surgery (1). Obesity is a risk factor for diabetes mellitus, hypertension, and kidney disease (2). Obesity has been shown to be a risk factor for renal function worsening and proteinuria after unilateral nephrectomy (3).
Bariatric surgery RYGB is associated with certain long-term complications (in addition to early complications like leaks, stenosis, and bleeding) including gallstone disease, marginal ulcerations, internal hernias and intussusception (4). Bariatric surgery RYGB has been shown to be associated with remission of hypertension in 60.4% and diabetes in 66.7% of subjects (5).
But RYGB is associated with renal risks including perioperative AKI, nephrolithiasis, and oxalate nephropathy (5). RYGB is associated with steatorrhea, leading to enteric hyperoxaluria and increased oxalate absorption (6).
A donor with prior history of passing small stone without recurrence and in presence of a normal CT KUB can be taken up, but considering history of RYGB, it is a red flag.
Long-term outcome in this scenario would be increased risk of nephrolithiasis and oxalate nephropathy (7).
In view of the reasons cited above, this donor should not be taken-up.
Instead, the person should be counselled regarding lifestyle modifications including further weight loss to reduce BMI, and dietary changes to prevent stone formation, including having adequate liquid intake, low oxalate, low salt, and low-fat diet. Vitamin B6 and potassium citrate supplementation might be required.
References:
1) Lentine KL, Kasiske BL, Levey AS, Adams PL, Alberú J, Bakr MA, Gallon L, Garvey CA, Guleria S, Li PK, Segev DL, Taler SJ, Tanabe K, Wright L, Zeier MG, Cheung M, Garg AX. KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors. Transplantation. 2017 Aug;101(8S Suppl 1):S1-S109. doi: 10.1097/TP.0000000000001769. PMID: 28742762; PMCID: PMC5540357.
2) British Transplantation Society. Renal Association Guidelines for Living Donor Kidney Transplantation, 4th ed.; British Transplantation Society: Macclesfield, UK, 2018; Available online: https//bts.org.uk/wp-content/uploads/2018/07/FINAL_LDKT-guidelines_June-2018.pdf (accessed on 3 October 2022).
3) Praga M, Hernández E, Herrero JC, Morales E, Revilla Y, Díaz-González R, Rodicio JL. Influence of obesity on the appearance of proteinuria and renal insufficiency after unilateral nephrectomy. Kidney Int. 2000 Nov;58(5):2111-8. doi: 10.1111/j.1523-1755.2000.00384.x. PMID: 11044232.
4) Lim R, Beekley A, Johnson DC, Davis KA. Early and late complications of bariatric operation. Trauma Surg Acute Care Open. 2018 Oct 9;3(1):e000219. doi: 10.1136/tsaco-2018-000219. PMID: 30402562; PMCID: PMC6203132.
5) Chang AR, Grams ME, Navaneethan SD. Bariatric Surgery and Kidney-Related Outcomes. Kidney Int Rep. 2017 Mar;2(2):261-270. doi: 10.1016/j.ekir.2017.01.010. Epub 2017 Jan 26. PMID: 28439568; PMCID: PMC5399773.
6) Carbone A, Al Salhi Y, Tasca A, Palleschi G, Fuschi A, De Nunzio C, Bozzini G, Mazzaferro S, Pastore AL. Obesity and kidney stone disease: a systematic review. Minerva Urol Nefrol. 2018 Aug;70(4):393-400. doi: 10.23736/S0393-2249.18.03113-2. Epub 2018 May 31. PMID: 29856171.
7) Espino-Grosso PM, Canales BK. Kidney Stones After Bariatric Surgery: Risk Assessment and Mitigation. Bariatr Surg Pract Patient Care. 2017 Mar 1;12(1):3-9. doi: 10.1089/bari.2016.0048. PMID: 28465866; PMCID: PMC5361755.
Three problems must be studied carefully
First: Risk of obesity on the donor
due to increased intraoperative complications with increase time of operation with the association of perioperative poorer wound healing and complications
Also, obesity may be associated with glomerular hyperfiltration and increased risk of proteinuria also may be at risk of secondary FSGS ((obesity-related glomerulopathy)) as Patients with higher BMI (31.6 ± 5.6 kg/m2) had a greater risk for the development of proteinuria and kidney insufficiency, with proteinuria appearing after 10.1 ± 6.1 years of donation )
African American kidney donors with BMI ≥ 35 kg/m2 had the highest rate of losing eGFR at a mean follow-up of 7.1 years. While the International Forum for the Care of the Live Kidney Donor advised that accepting obese candidates as potential kidney donors should be individualized according to acute and long-term risks, they still discourage donations from those with BMI > 35 kg/m2 and recommend weight loss prior to donation
Also, Obesity is associated with risk of Hypertension , DM , Fatty liver and steatosis which may affect kidney functions later on .
The second problem was a history of Gastric Bypass with risk of Malnourishment , fluid loss, dehydration , vitamin D loss, and Hypocalcaemia with an increase of Oxalates absorption >> so an increase risk of Oxalates stones
Third Problem Previous history of renal stones
so I will accept the donor if the only donor is available and long waiting list for the deceased donor
the donor must lose Weight and council about to keeping on his weight
increase fluid intake by more than 3 liters per day
the metabolic profile must be done to ensure a low risk of renal stones recurrence
Close follow-up of the donor is needed
Rashidbeygi E., Safabakhsh M., Aghdam S.D., Mohammed S.H., Alizadeh S. Metabolic syndrome and its components are related to a higher risk for albuminuria and proteinuria: Evidence from a meta-analysis on 10,603,067 subjects from 57 studies. Diabetes Metab. Syndr. Clin. Res. Rev. 2018;13:830–843. doi: 10.1016/j.dsx.2018.12.006
Acute Kidney Injury after Gastric Bypass Surgery
Charuhas V. Thakar, Varsha Kharat, Sheila Blanck and Anthony C. Leonard
CJASN May 2007, 2 (3) 426-430; DOI: https://doi.org/10.2215/CJN.03961106
A 47-year-old male is keen to donate a kidney to his brother, 000 mismatches, no DSA and FCXM is negative. Excellent kidney function. He gave a past history of Roux en Y gastric bypass (RYGB) for morbid obesity 7 years ago. His current BMI is 32. He also passed a small stone 5 years ago, which never recurred. CT KUB is normal.
How do you manage this case?
the problems of this donor include a previous history of morbid obesity and post BYPASS Roux en y still is BMI > 30 so he is at metabolic risk including the risk of DM, HTN, dyslipidemia, secondary oxalosis, CAD.
past surgical history of Roux en Y gastric bypass referred to a malabsorption type of bariatric surgery associated with higher metabolic risk like DM, and secondary hyperaxolosis. RYGB is likely related to the association between obesity and hyperoxaluria. Hyperoxaluria in obesity is thought to be secondary to inflammation causing increased oxalate absorption in the gut. this patient had a previous history of kidney stones 5 years ago so he is at risk of recurrence of oxalosis post-donation.
Hyperoxaluria in obesity is thought to be secondary to inflammation causing increased oxalate absorption in the gut. this patient had previous history of kidney stones 5 years ago so he is at risk of recurrence of oxalosis post donation. the multivariate relative risk for developing kidney stones with a BMI of >30 kg/m2 is 2.09 in young women, 1.90 in older women, and 1.33 in men (2) Calcium oxalate stones are the most common stone type reported after RYGB due to the low urine volume with high urine calcium oxalate excretion and low urine citrate.
Obesity is associated with hyperfiltration and proteinuria which is even more post-donation
he is at risk of surgical complications including surgical hematoma bleeding, infection, and hernia due to obesity
I think this donor better decline for now as he needs to reduce his wt., assess him for other metabolic factors like GTT and proteinuria, Hb aic, lipid profile 24 h urine citrate and oxalate, advise for diet modification low oxalate low fat and high fruits and regular calcium supplement with meals and urinary alkalizer like potassium and calcium citric acid, so need to be discussed in details the above medical and surgical risk for the donor and referred to independent living donor advocate for further assessment.
References
1.BTs guideline 2018
2. Taylor EN, Stampfer MJ, Curhan GC: Obesity, weight gain, and the risk of kidney stones. JAMA 293: 455–462, 2005 10.1001/jama.293.4.455
_ The current potential living kidney donor has risk factors for CKD progression after living donor kidney nephrctomy:
_ being obese now with BMI of 32 which can be associated with all complications of obesity as secondary FSGS with progressive proteinuria and CKD (hyperfilteration injury), hypertension and diabetes which can lead to CKD especially after nephrectomy.
_obesity also affect cardiovascular outcome so evaluation with stress ecg, stress echo and CPET to evaluate his cardiovascular reserve.
_ previous history of roux on Y anastomosis for obesity is another risk factor for malabsorption, vitamin D deficency, hypocalcemia, and hyperoxaluria. This can predispose him to oxalate stones (previous history of stone passing )that can recuer and is hazardous in single kidney, so metabolic screen is essential even if KUB CT us free.
_ higher risk of perioperative complications as wound dehiscence related to obesity.
So the current donor should be declined.
__If he is the only available option , proper counseling as regard the risk of CKD progression, advise him to lose weight before transplant to minimize perioperative complications, and decrease the risk of metabolic syndrome (diabetes, hypertension and dyslipidemia).
In addition, plenty of water up to 3 liters per day to prevent oxalate stone, in addition lit protein intake and increase potassium citrate intake.
Reference is BTS 2018.
Not sure about this. maybe take the opinion of my Gastroenterology and Gastrosurgery colleagues regarding the possibilities of diet modifications to minimise the chances of recurrence. would have to search literature for this kind of situation.
● Roux en y gastric bypass is apredisposing factor for secondry hyperoxaluria which in turn leads to nephrolithiasis formation
● Obesity also leads to metabolic abnormalities and it is arisk factor for hypertention , DM , CKD , and CVD
● So it is better to exclude this donor
● But as the donor 000 mismatch, no DSA and FCXM is negative. Excellent kidney function he is low immune
● So I will recosider him for donation after
◇ Careful evaluating for hypertension , CVD . CKD Prediabetes , PAD , and respiratory diseases
◇ Counselled donor about the increased risk of peri-operative complications
◇ Counselled donor about the long-term risk of kidney disease
◇ Advised to lose weight before donation and to maintain their ideal weight following donation.
◇ ffor protection from stone recurrence I will advise him for adequte hydration with diet rich with calcium and poor oxalate
◇ if the donor BMI decrease to less 30 I will proceed transplantation
● The long-term outcome of kidney donation
* Peri-operative complications
* Hypertension
* CVD
* PAD
* DM
* Metabolic Syndrome
* CKD
* Respiratory disease
● Please substantiate your answer
BTS/RA Living Donor Kidney Transplantation Guidelines 2018
Thank you. How do you make him a suitable donor?
1- BMI >32 despite of bariatric surgery
2- risk of stone formation after the bariatric surgery
Thank you. How do you make him a suitable donor?
How do you manage this case?
The potential donor is obese, despite his past history of gastric bypass for morbid obesity. Obesity is considered a relative contra-indication to living kidney donation because of the increased risk of surgical complications and the adverse impact of obesity on renal function in the longer term1.
I will not accept this donor as his BMI is 32 despite the bypass surgery. He is young and may have all the complications and long-term sequelae of donation.
What is the long-term outcome of kidney donation?
a) The principal concern for the obese living donor is the possibility that donation may have an adverse effect on long-term kidney function.
b) Obesity associated co-morbidities such as hypertension, diabetes and the metabolic syndrome may compromise future kidney function.
c) Data suggest that obesity is independently associated with a higher risk of developing end stage kidney disease.
d) Focal glomerulosclerosis and obesity-related glomerulopathy (glomerular enlargement and mesangial expansion) with associated proteinuria have been described in patients with severe obesity and may be reversible with weight loss.
e) Obesity is a risk factor for renal insufficiency after unilateral nephrectomy.
f) At 10 years post-nephrectomy, 60% of patients whose BMI was >30 kg/m2 at the time of nephrectomy developed proteinuria (>3 g/day) and 30% developed renal insufficiency (creatinine clearance <70 mL/min). These data suggest that nephrectomy in obese patients increases the risk of developing proteinuria and/or renal insufficiency1.
Reference
1. BTS/RA Living Donor Kidney Transplantation Guidelines 2018
Thank you. How do you make him a suitable donor?
I will not accept him as a donor
He is obese though BMI is still less than 35 which is a contraindication for donation
Risk of stone recurrence
Gastric by pass surgery also poses increased risk for stone formation
There will be increased risk of
perioperative complications
Hypertension
Diabetes
Metabolic syndrome
proteinuria
Secondary FSGS
increased risk of mortality
Obese LKDs had a 30% increased risk of long-term mortality compared to their non-obese counterparts (aHR: 1.32, 95%CI: 1.09–1.60, p=0.006). The impact of obesity on mortality risk did not differ significantly by sex, race/ethnicity, biological relationship, baseline eGFR, or among donors who did and did not develop post-donation kidney failure.
Obesity and Long-Term Mortality Risk among Living Kidney DonorsJayme E. Locke, MD, MPH, Rhiannon D. Reed, MPH, […], and Dorry L. Segev, MD,
Thank you. See my question above
Bariatric surgery is an effective bridge before renal transplant both for obese donors and obese recipients. for donors, the risks of obesity are more than with this surgery, but mortality is more with Roux and Y surgery. (1). still is more effective than sleeve gastrectomy. After a successful operation, long-term complications of malabsorption and hyperoxaluria are considerations.
From the donor side, as in our scenario already operated, this operation is done the nephrolithiasis is still a risk but has he passed a small stone 5 years ago, and the CT KUB is normal, we may proceed with transplantation after explaining the possible risks that may he face. Also, we have to ensure maintenance of body weight because as his BMI is 32, non-adherence and an increase in body weight will put him in face of weight gain problems and de novo kidney disease.
There is a risk of renal complications due to hyperoxaluria, calcium oxalate stones and oxalate nephropathy (2).
1- Bariatric surgery for obese live kidney donors: an analysis of risks and benefits (DOI: 10.15761/IOD.1000186)2- (Canales BK, Gonzalez RD. Kidney stone risk following Roux-en-Y gastric bypass surgery. Transl Androl Urol. 2014;3(3):242-249. doi:10.3978/j.issn.2223-4683.2014.06.02).
Thank you. So, do you think he is a suitable donor?
We have many challenges:
1. Weight
2. Condition that causes hyperoxaluria
3. Passed s stone five years ago
How do you prepare him and make him suitable to donate?
Dear Dr Ahmed,
I think by modifying the risk factors mentioned in this case scenario, we can prepare this person -who is keen to donate to his brother- to be a suitable donor.
How do you manage this case?
-The donor’s BMI is 32 , so he is obese. Obesity is considered a relative contra-indication to living kidney donation because of the increased risk of surgical complications and the adverse impact of obesity on renal function in the longer term. The presence of obesity in kidney donors is associated in some studies with an increase in peri-operative complications, although these are mostly relatively minor.
-RYGB patients demonstrate higher supersaturation of calcium oxalate, higher urinary oxalate levels, lower urine volumes, and hypocitraturia in 24-h urine analysis, placing them at increased stone risk. Supersaturation of the urine with stone-forming salts is a critical factor in crystallization . RYGB can increase stone risk in patients with or without previous kidney stone history.
-I will not accept this donor.
What is the long-term outcome of kidney donation?
The principal concern for the obese living donor is the possibility that donation may have an adverse effect on long-term kidney function. Obesity-associated
co-morbidities such as hypertension, diabetes and metabolic syndrome may compromise future kidney function. In addition, data suggest that obesity is
independently associated with a higher risk of developing end stage kidney disease
. Focal glomerulosclerosis and obesity-related glomerulopathy (glomerular
enlargement and mesangial expansion) with associated proteinuria have been
described in patients with obesity . Obesity is also a risk factor for renal insufficiency after unilateral nephrectomy.
At 10 years post-nephrectomy, 60% of patients whose BMI was >30 kg/m2 at the
time of nephrectomy developed proteinuria (>3 g/day) and 30% developed renal
insufficiency (creatinine clearance <70 mL/min) .
Reference:
-BTS/RA Living Donor Kidney Transplantation Guidelines 2018.
Thank you.
How do you manage this case?
This donor is low immunological risk but has history of bypass. He is at high risk of developing nutritional and metabolic abnormalities. There is high risk of deficiency of Vitamin A,D,E,K, Iron, Folic Acid, negative calcium balance and vitamin D deficiency causing secondary hyperparathyroidism .
There will be mal absorption of bile salts which can lead to Oxalosis. It can lead to stone formation. There can be increased bacterial growth leading to diarrhoea thus causing dehydration. Because of high fats in bowel calcium combines with fats so less calcium is available to chelate oxalate, This caused hyperoxaluria.
Also hypovolemia and hypocitraturia can cause stone formation.
Thus I will decline this donation.
if no alternative option is available then he should have full metabolic screen and both donor and recipient should he counselled in detail explaining risk of stone formation, change of life style. high fluid intake etc.
What is the long-term outcome of kidney donation?
There can higher risk of urolithiasis
Thank you. Very clear
INTRODUCTION :
Ø Bariatric surgery for weight loss has become a common practice in the United States, with about 179,000 operations performed in 2013. The second most common bariatric procedure done today is the Roux-en-Y gastric bypass (RYGB). To be a practicing health professional in the modern era, one must understand the more common chronic complications that may result from altering the gastrointestinal (GI) tract and how to manage these complications.
Ø Roux-en-Y gastric bypass involves creating a small gastric pouch (restricting food intake) connected to a roux limb (typically between 75 to 150 cm) which bypasses a large portion of the small intestine (preventing the absorption of nutrients.) This results in the food bolus bypassing most of the stomach (bypasses the part of the stomach containing most of the parietal cells and stomach acid), the duodenum, and the first 40 to 50 cm of jejunum. Nutrients will only be absorbed distal to these bypassed segments, and the majority will be absorbed in the “common channel,” which is distal to where the biliopancreatic and the roux limb connect.
Ø Roux-en-Y gastric bypass is a commonly performed operation today in the United States. It has many advantages over other weight-loss surgeries but can present with early and late complication
The common chronic complications:
1-Anastomotic Stricture
2- Marginal Ulceration
3- Gastro-Gastric Fistula (GGF)
4- Cholelithiasis
5- Choledocholithiasis
6- Small Bowel Obstruction (SBO)
7- Dumping Syndrome
8- Nutritional Complication
A healthcare practitioner must be aware of these sequelae and their management.
MANAGEMENT :
1-The management of obesity requires an interprofessional team of providers, including an internist, primary care provider, nurse practitioner, dietitian, bariatric surgeon, sociologist, physical therapist, and an endocrinologis
2-Roux-en-Y gastric bypass is a commonly performed operation today in the United States. It has many advantages over other weight-loss surgeries but can present with early and late complications
3- Moderately obese patients (BMI 30-35 kg/m2) must undergo careful preoperative
evaluation to exclude cardiovascular, respiratory and kidney disease.
4- Moderately obese patients (BMI 30-35 kg/m2) must be counselled about
the increased risk of peri-operative complications based on extrapolation of outcome data from very obese donors (BMI >35 kg/m2).
5- Moderately obese patients (BMI 30-35 kg/m2) must be counselled about the long-term risk of kidney disease and be advised to lose weight before donation and to maintain their ideal weight following donation
REFERNCES :
1-BTS guidelines 2-Roux-en-Y Gastric Bypass Chronic Complications
Thank you, Nahla. Will you accept him as a donor or not?
A high BMI that is greater than 35-40 kg/m2 is a contraindication for kidney donation due to the increased risk of peri-operatory and post-operatory complications. Also, they are at high risk of metabolic abnormalities and as such kidney stones. Now a procedure called Roux en Y gastric bypass can be used to help to lose weight. The problem with this surgery is the complications that occur as related to the kidneys.
It was found that there will be renal complications of hyperoxaluria, calcium oxalate stones, and oxalate nephropathy.
The above patient had a history of passing kidney stones over 5 years ago. With this in mind, the patient must be studied that is metabolic studies, imaging like an abdominal ultrasound, and CT Scan to ensure there are no kidney stones or other complications.
Most centers consider a BMI of 30 kg/m2 not allowed to be a donor for kidney transplantation due to the increased risk of morbidity and mortality. As such it is recommended that the patient should be placed on a weight reduction program.
The patient should continue to be on a weight loss plan. The patient due to the surgical procedure will continue to have complications and affectation at the level of the kidney. So as such the patient is not a candidate for a donor.
References:
Canales, K.B., Gonzalez, D.R., TAU (2014). Kidney stone risk following Roux en Y gastric bypass surgery: tau.amegroups.com/article/view/4134/5589
Siegfried, J., Obesity (2020): The risks of obesity for organ donation.
Thank you.
The patient has moderate obesity and must undergo careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease.
He also must be counselled about the increased risk of peri-operative complications based on extrapolation of outcome data from very obese donors (BMI >35 kg/m2) and
the long-term risk of kidney disease and be advised to lose weight before donation and to maintain their ideal weight following donation.
His median life expectancy is reduced by 2-4 years which is comparable with the effects of smoking.
The presence of obesity in kidney donors is associated in some studies with an increase in peri-operative complications, although these are mostly relatively minor in nature such as wound debridement
At 10 years post-nephrectomy, 60% of patients whose BMI was >30 kg/m2 at the
time of nephrectomy developed proteinuria (>3 g/day) and 30% developed renal
insufficiency (creatinine clearance <70 mL/min)
obese patients increases the risk of developing proteinuria and/or renal insufficiency.
Bariatric surgery is associated with improvements in metabolic outcomes, malabsorption occurs and is associated with increased risk of kidney stones related to high 24-hour urine calcium oxalate supersaturation , low urine citrate, and low urine volume. Certain dietary recommendations after surgery may help treat those urine changes and decrease risk of renal stones.
So, moderate obesity with history of bariatric surgery makes him high risk donor. I would exclude him from kidney donation.
As the % of 60% to develop 3gm proteinuria is quite significant so:
was it due to uncontrolled obesity for 10 years or has a relation to nephrectomy?
This donor is obese grade I, should be counselling regarding maintaining weight less than 30 before donation and evaluate for peri operative cardiovascular and pulmonary risk.
He has history of pass renal stone 5 years, so should evaluate regarding recurrence of stone especially patients underwent bariatric surgery because risk of calcium oxalate stone due to low volume and low urinary oxalate.
Also should counselling the donor for risk of hypertension and diabetes. should be monitoring weight and diet to reduce recurrence stone and reduce risk of hypertension
There’s risk of recurrence renal stone of calcium oxalate
So what is your decision for this lady.?
Although bariatric surgery is associated with improvements in metabolic outcomes, malabsorption occurs and is associated with increased risk of kidney stones related to high 24-hour urine calcium oxalate supersaturation , low urine citrate, and low urine volume. Certain dietary recommendations after surgery may help treat those urine changes and decrease risk of renal stones.
A study revealed that the multivariate relative risk for developing kidney stones with a BMI of ≥30 kg/m2 is 1.33 in men and the risk continues to rise to 14% 10 years post surgery.
This donor has 2 morbidities indicating that it is better to decline this donor , those morbidities are obesity and history of renal stones ,although his current CT is free of stones he is liable to recurrence of stones.
Regarding obesity BMI >30 kg considered obesity class I ,which by itself can cause increased risk of perioperative complications and comorbidities as DM , HTN also obesity negatively affects the kidney in the form of obesity related glomerulopathy and focal glomerulosclerosis along with higher risk of renal failure post nephrectomy, superadded to that risk is the renal stone history indicating the presence of metabolic disturbance that occurs post Roux En Y surgeries due to hyperoxaluria .
But if there is necessity to donate the patient needs metabolic profile evaluation along with dietary treatment and weight loss programs will be essential along with pre transplant assessment as he is a risky donor .
Counselling is necessary for both donors and recipeint explaining to the donor the long term risks of stone formation, cardiovascular ,DM ,HTN and renal failure on long term bases.
Reference
-Prochaska M. and Worcester E. Risk Factors for Kidney Stone Formation following Bariatric Surgery. KIDNEY360 1: 1456–1461, 2020.
-Professor Roberto Cacciola lecture.
Well done ,the bariatric surgery will be always there with possible stone formation.
Our patient had history of morbid obesity which is treated by bariatric surgery (Roux en Y gastric bypass) 7 years ago which is complicated by one stone 5years ago and now he is BMI 32.
We should take care of two points:
First is his moderate obesity :
1-Sholud advised to lose weight before donation and to maintain their ideal weight following donation.
2-Should undergo careful preoperative evaluation to exclude cardiovascular, respiratory and kidney disease.
3-Should be counselled about the increased risk of peri-operative complications and the long-term risk of kidney disease.(1).
Second point is Roux en Y gastric bypass and its nephrolithiasis complications:
1- patients have a higher risk of developing nephrolithiasis after RYGB (pooled relative risk 1.79, 95% CI 1.54-2.10) (2) because it is associated with higher calcium oxalate super-saturation and urine oxalate, lower citrate, and lower volume.
2- oxalate nephropathy and renal failure which is due to increased absorption of calcium oxalate particular if associated with other co-morbidity (3).
Our case has moderate obesity & history of one stone 5 years ago so, should be metabolically evaluated for any urinary abnormalities in 24 hour urine if associated with higher calcium oxalate super-saturation and urine oxalate, lower citrate, and lower volume better to exclude him from donation.
What is the long-term outcome of kidney donation?
Obesity was not associated with a statistically significant difference in surgical mortality(4), Obesity is also a risk factor for renal insufficiency after unilateral nephrectomy with mild increase in proteinuria(5,6).
References:
1- BTS/RA Living Donor Kidney Transplantation Guidelines 2018
2-Upala S, Jaruvongvanich V, Sanguankeo A. Risk of nephrolithiasis, hyperoxaluria, and calcium oxalate super-saturation increased after Roux-en-Y gastric bypass surgery: a systematic review and meta-analysis. Surg Obes Relat Dis. 2016;12(8):1513-1521. doi:10.1016/j.soard.2016.04.004.
3-Nasr SH, D’Agati VD, Said SM, et al. Oxalate nephropathy complicating Roux-en-Y Gastric Bypass: an underrecognized cause of irreversible renal failure. Clin J Am Soc Nephrol. 2008;3(6):1676-1683. doi:10.2215/CJN.02940608.
4-Segev DL, Muzaale AD, Caffo BS, et al. Perioperative mortality and long-term survival following live kidney donation. JAMA 2010; 303: 959-66.
5- Kambham N, Marcowitz GS, Valeri AM, Lin J, D’Agati VD. Obesity related glomerulopathy; an emerging epidemic. Kidney Int 2001; 59: 1498-509.
6- Praga M, Hernandez E, Herrero JC, et al. Influence of obesity on the appearance of proteinuria and renal insufficiency after unilateral nephrectomy. Kidney Int 2000; 58: 2111-8.
In your last paragraph :
which degree of obesity BMI can develop significant proteinuria 10 years post nephrectomy and is it a complication of obesity or also related to donation as well.
Thanks prof.Dawlat.
IN this study among the 14 obese (BMI > 30 kg/m(2)) patients at the time of nephrectomy, 13 (92%) developed proteinuria/renal insufficiency. In contrast, among the 59 patients with BMI < 30 kg/m(2), only 7 (12%) developed these complications (P < 0.001).
In the general population, obesity is associated with increased morbidity and mortality. For a BMI of 30-35 kg/m2, the median life expectancy is reduced by 2-4 years and for a BMI of 40-45 kg/m2, it is reduced by 8-10 years, which is comparable with the effects of smoking. In comparison with individuals of normal weight, overweight and obese individuals are at increased risk of hypertension, hypercholesterolemia, insulin resistance and diabetes, heart disease, stroke, sleep apnoea and certain cancers
Obesity is considered a relative contra-indication to living kidney donation because
of the increased risk of surgical complications and the adverse impact of obesity on renal function in the longer term. Obesity is also a risk factor for renal insufficiency after unilateral nephrectomy.
At 10 years post-nephrectomy, 60% of patients whose BMI was >30 kg/m2 at the time of nephrectomy developed proteinuria (>3 g/day) and 30% developed renal insufficiency (creatinine clearance <70 mL/min) (13). These data suggest that nephrectomy in obese patients increases the risk of developing proteinuria and/or renal insufficiency
Moderately obese patients (BMI 30-35 kg/m2) must be counselled about the increased risk of peri-operative complications based on extrapolation of outcome data from very obese donors (BMI >35 kg/m2). (B1)
· Moderately obese patients (BMI 30-35 kg/m2) must be counselled about the long-term risk of kidney disease and be advised to lose weight before donation and to maintain their ideal weight following donation. (B1)
· Data on the safety of kidney donation in the very obese (BMI >35 kg/m2)
are limited and donation should be discouraged. (C1)
The Roue-en-Y gastric bypass is considered the gold-standard weight loss operation as it has proven success at durable weight reduction and reversal of obesity-associated comorbidities. Due to its malabsorptive nature, the Roue-en-Y gastric bypass is, however, associated with the potential of long-term nutritional and metabolic derangements. In the particular context of kidney donation, these metabolic derangements can alter the urinary milieu, leading to an approximately twofold increase risk of calcium oxalate nephrolithiasis and the rare possibility of developing oxalate nephropathy. The BPD with duodenal switch, which leads to even more malabsorption as well as nutritional and metabolic derangements than the Roue-en-Y gastric bypass, carries the similar increased risk of nephrolithiasis and oxalate nephropathy.
My decision
I will no accept her as a kidney donor unless, she is the last option for a patient with exhausted vascular access of dialysis, long waiting list, acceptable cross match
References
· BTS/RA Living Donor Kidney Transplantation Guidelines 2018, page 86- 89
· Bariatric surgery prior to living donor nephrectomy: a solution to expand the living donor kidney pool – a retrospective study
Minh-Tri J. P. Nguyen,Dustin Carpenter,Joseph Tadros,Abhishek Mathur,Pedro Rodrigo Sandoval,E. Steve Woodle,Tayyab Diwan,Lloyd E. Ratner
First published: 05 February 2019
https://doi.org/10.1111/tri.13408
That is a superb, reply, Dr Michael Farag.