Risk factors for urinary complications after renal transplantation

Approach to Kidney Allograft Dysfunction: A Brief Review

It is important for providers caring for kidney transplant recipients to be familiar with the common causes of allograft dysfunction. Early detection of allograft dysfunction leads to timely management, with the goal of preventing or delaying progression to allograft failure. Although transplant rejection is always a concern, the differential diagnoses for allograft dysfunction are broad and include perioperative complications, infections, recurrent disease, and calcineurin nephrotoxicity. In this review, we will go over early and late causes of allograft dysfunction and discuss the basic workup and principles of management for each condition.

Rectus sheath patch. A novel surgical technique in the repair of isolated renal pelvis necrosis in a transplanted kidney. A case report

INTRODUCTION

Focal necrosis of the renal pelvis in a transplanted kidney is a rare but often morbid complication that may lead to graft loss. Given the scarcity of donor organs, all attempts are made to preserve the graft. Currently there is no standard surgical technique for reconstruction or repair of isolated renal pelvic necrosis.

PRESENTATION OF CASE

A 70-year-old male with end stage kidney disease underwent renal transplantation. The patient developed a day-three post-operative urine leak. During surgical exploration, a focal area of pelvic necrosis was observed without evidence of proximal or distal ureteric involvement. Given the excellent function of the renal allograft, a novel surgical technique was successfully used to repair the necrotic defect. Reconstruction of the renal pelvis was performed using an avascular rectus sheath patch. The patch was secured over the open pelvis following necrotic tissue debridement. The patient made a successful recovery with complete resolution of urine leak. A 6-week post-operative retrograde pyelogram confirmed no ongoing urine leak.

DISCUSSION

To restore anatomy, the pelvic defect was patched with avascular rectus sheath fascia. Advantages of this reconstructive method were technique simplicity and low donor site morbidity. Potential complications included patch failure with ongoing urine leak, ventral wall hernia through the fascial donor site and stenosis of the ureteropelvic junction.

CONCLUSION

This case highlights the successful surgical management of a renal pelvis urine leak patched with rectus sheath fascia. This technique could be considered as a graft saving procedure in similar cases where the alternative is transplant nephrectomy.

Contrast-enhanced US in Renal Transplant Complications: Overview and Imaging Features

Renal transplant is the first-line treatment of end-stage renal disease. The increasing number of transplants performed every year has led to a larger population of transplant patients. Complications may arise during the perioperative and postoperative periods, and imaging plays a key role in this scenario. Contrast-enhanced US (CEUS) is a safe tool that adds additional value to US. Contrast agents are usually administered intravenously, but urinary tract anatomy and complications such as stenosis or leak can be studied using intracavitary administration of contrast agents. Assessment of the graft and iliac vessels with CEUS is particularly helpful in identifying vascular and parenchymal complications, such as arterial or venous thrombosis and stenosis, acute tubular injury, or cortical necrosis, which can lead to graft loss. Furthermore, infectious and malignant graft involvement can be accurately studied with CEUS, which can help in detection of renal abscesses and in the differentiation between benign and malignant disease. CEUS is also useful in interventional procedures, helping to guide percutaneous aspiration of collections with better delimitation of the graft boundaries and to guide renal graft biopsies by avoiding avascular areas. Potential postprocedural vascular complications, such as pseudoaneurysm, arteriovenous fistula, or active bleeding, are identified with CEUS. In addition, newer quantification tools such as CEUS perfusion are promising, but further studies are needed to approve its use for clinical purposes. ©RSNA, 2024 Supplemental material is available for this article.

Ureterovesical Leak Following Renal Transplant and Effects of Acute Rejection and Antirejection Therapy: A Nested Case-Control Analysis and Outcome of 1102 Consecutive Renal Transplant Recipients

OBJECTIVES

Studies on nontechnical risk factors for ureterovesical leak after renal transplant are scarce. This study aimed to report the possible pre- and postoperative risk factors and the role of acute rejection and antirejection therapies for urine leak after transplant and its effect on graft and patient survival.

MATERIALS AND METHODS

We conducted a retrospective analysis of 13 patients (1.17%) with urine leak (case group) and 52 patients without leak (control group) (case-to-control ratio of 1:4) from 1102 living related (first degree) renal transplant recipients seen between January 2012 and December 2021. We analyzed demographic and clinical details and biochemical and outcome parameters using a nested case-control design.

RESULTS

Cases were olderthan controls (P = .018), were more ABO incompatible (P = .009), and had more 6/6 HLA mismatch transplants (P = .047). Donors of cases were older than donors of controls (P = .049). The rate of postoperative hypoalbuminemia was greaterin the case group (P = .050). Rates of acute rejection (P = .012) and plasmapheresis (P = .003) were greaterin the case group than in the control group. On multivariate logistic regression analysis, recipient age, 6/6 HLA mismatch, and plasmapheresis were found to independently associated with urine leak. None ofthe patient required surgical repair, as all responded to conservative therapy. Urine leak did not affect graft outcomes (P = .324), but overall survival was less in cases than in controls.

CONCLUSIONS

Nontechnical risk factors that cause posttransplant ureteric leak include older donor and recipient age and ABO incompatible and 6/6 HLA mismatch transplants. Acute rejection and plasmapheresis predispose leak, and an indwelling double J stent can allow adequate healing of the anastomosis. High index of suspicion and prompt management are imperative to preserve graft and patient outcome.

Evaluation of technical urinary tract complications in kidney transplantation recipients with a prolonged dialysis history

BACKGROUND

The kidney transplant waiting list continues to expand, resulting in prolonged dialysis times exceeding 8 years before transplantation in some regions. The relationship between long-term dialysis and urinary tract complications after kidney transplant remains largely unexplored. This study aims to evaluate post-kidney transplant complications in patients with a history of prolonged dialysis.

METHODS

A single-center, retrospective cohort study of patients maintained on dialysis ≥8 years before kidney transplant between January 2000 and July 2020 was conducted. Clinical variables, including demographics and comorbidities, were reviewed. The primary objective was the development of a technical urinary tract complication. Secondary outcomes included any postoperative complication by type, stratified by medical and surgical complications.

RESULTS

Overall, 376 patients met the inclusion criteria. The mean pre-kidney transplant dialysis time was 10.2 ± 2.6 years. The majority (65.7%) of the study participants were anuric. Four patients (1.1%) experienced a urine leak, and 8 patients (2.1%) had a ureteral stricture. Any complication was observed in 111 (29.5%) patients, with urinary tract infections being the most common. Urinary catheters remained in place for a median of 4 (3, 5) days. Drains were commonly used (62.8%) for a median of 5 (4, 6) days.

CONCLUSION

In our large, single-center experience with kidney transplants in high-risk patients with prolonged dialysis and anuria, the technical urinary tract complications rate remained low. With the current literature consisting of small cohorts and having relatively short pre-kidney transplant dialysis periods, our analysis addresses the shortcomings of the literature while suggesting that this patient population may not truly be "high risk."

Ureterovesical Anastomosis Complications in Kidney Transplantation: Definition, Risk Factor Analysis, and Prediction by Quantitative Fluorescence Angiography with Indocyanine Green

Ureteral stenosis and urinary leakage are relevant problems after kidney transplantation. A standardized definition of ureterovesical anastomosis complications after kidney transplantation has not yet been established. This study was designed to demonstrate the predictive power of quantitative indocyanine green (ICG) fluorescence angiography. This bicentric historic cohort study, conducted between November 2015 and December 2019, included 196 kidney transplantations. The associations between quantitative perfusion parameters of near-infrared fluorescence angiography with ICG and the occurrence of different grades of ureterovesical anastomosis complications in the context of donor, recipient, periprocedural, and postoperative characteristics were evaluated. Post-transplant ureterovesical anastomosis complications occurred in 18%. Complications were defined and graded into three categories. They were associated with the time on dialysis (p = 0.0025), the type of donation (p = 0.0404), and the number of postoperative dialysis sessions (p = 0.0173). Median ICG ingress at the proximal ureteral third was 14.00 (5.00–33.00) AU in patients with and 23.50 (4.00–117.00) AU in patients without complications (p = 0.0001, cutoff: 16 AU, sensitivity 70%, specificity 70%, AUC = 0.725, p = 0.0011). The proposed definition and grading of post-transplant ureterovesical anastomosis complications is intended to enable valid comparisons between studies. ICG Fluorescence angiography allows intraoperative quantitative assessment of ureteral microperfusion during kidney transplantation and is able to predict the incidence of ureterovesical anastomosis complications. Registration number: NCT-02775838.

Contemporary risk factors for ureteral stricture following renal transplantation

INTRODUCTION

Allograft ureteral strictures after renal transplantation impact graft function and increase patient morbidity. They can be challenging to treat and may require complex surgical repair. Therefore, the objective of this study was to identify contemporary risk factors for the development of post-renal transplant ureteral strictures.

METHODS

A retrospective analysis was performed on all renal transplant patients at Vancouver General Hospital from 2008-2019. Demographics, clinical parameters, and outcomes were compared between patients who did and did not develop ureteral strictures. Putative risk factors for ureteral stricture were analyzed using logistic regression.

RESULTS

A total of 1167 patients were included with a mean followup of 61.9±40.8 months. Ureteral strictures occurred in 25 patients (2.1%). Stricture patients had no demographic differences compared to non-stricture patients but had significantly higher rates of postoperative complications, longer hospital stays, and decreased renal function one year post-transplant (all p<0.05). On multivariable analysis, cold ischemia time >435 minutes (odds ratio [OR] 43.9, confidence interval [CI] 1.6-1238.8, p=0.027), acute rejection (OR 3.0, CI 1.1-7.4, p=0.027), and postoperative complications (OR 112.4, CI 2.4-5332.6, p=0.016) were risk factors for stricture.

CONCLUSIONS

Renal transplant patients with ureteral stricture experience greater morbidity and reduced post-transplant renal function compared to non-stricture patients. Our findings support attempts to reduce cold ischemia time, acute rejection, and postoperative complications to mitigate this potential complication. Our study is limited by the low incidence of ureteral stricture resulting in a small sample of stricture patients. Future research in a larger, multicenter setting is warranted.

Urolithiasis in a Deceased Donor Kidney Transplant Recipient: Case Report

Urolithiasis is a rare complication among kidney transplant recipients, with an incidence of 0.4% to 4.4%. Saudi Arabia has a very hot environment for most of the year, which has been linked to an increased incidence of nephrolithiasis. Additionally, animal protein consumption promotes stone development. Saudi Arabia has 2.5 times the number of stone formation indications as the rest of the world. Several features of urolithiasis and stone composition have already been discussed. The most frequent stone composition is calcium oxalate, followed by uric acid. We discuss the case of a 35-year-old Indian male brain death donor who presented after an automobile accident and had no history of chronic illness. One of his kidneys was transplanted into a female patient. She complained with flank pain and dysuria numerous times after transplant, which turned out to be a urinal track infection. She thereafter developed hematuria with burning micturition, and tests revealed that she had a large renal bladder stone as well as several pelvic kidney stones. The patient received lithotripsy and the stone was removed, and her kidney function was restored.

Taguchi versus Lich-Grégoir Extravesical Ureteroneocystostomy in Kidney Transplantation: A Systematic Review

INTRODUCTION

Ureteric implantation of the transplanted ureter into native urinary bladder tissue in kidney transplantation recipients is essential for post-operative kidney function. We aimed to determine the effects of Taguchi versus Lich-Grégoir extravesical ureteroneocystostomy in kidney transplantation.

METHODS

We searched multiple databases (MEDLINE, Cochrane Library, and Web of Science), trial registries, and conference proceedings until March 2021. We included prospective studies comparing Taguchi and Lich-Grégoir ureteroneocystostomy in kidney transplantation. Two review authors independently screened the identified records, extracted data, evaluated the risk of bias using ROBINS-I, and assessed the certainty of evidence according to GRADE.

RESULTS

We identified 3 prospective studies with serious or critical risk of bias, leading to low-certainty evidence. We downgraded the risk of bias due to study limitations. Assessment and/or reporting of baseline imbalances, co-interventions, and confounding factors was insufficient in all included studies. The effect of Taguchi ureteroneocystostomy remains unclear.

CONCLUSION

Currently available evidence is not useful to determine the effect of Taguchi versus Lich-Grégoir ureteroneocystostomy in kidney transplantation. There is a need for methodologically better designed and executed studies, such as randomized controlled trials with long-term follow-up reporting baseline imbalances, co-interventions, and confounding factors.

Kidney transplantation from expanded criteria donors: an increased risk of urinary complications - the UriNary Complications Of Renal Transplant (UNyCORT) study

OBJECTIVES

To assess the impact of expanded criteria donors (ECD) on urinary complications in kidney transplantation.

PATIENTS AND METHODS

The UriNary Complications Of Renal Transplant (UNyCORT) is a cohort study based on the French prospective Données Informatisées et VAlidées en Transplantation/Computerized and VAlidated Data in Transplantation (DIVAT) cohort. Data were extracted between 1 January 2002 and 1 January 2018 with 1-year minimum follow-up, in relation to 44 pre- and postoperative variables. ECD status was included according to United Network for Organ Sharing (UNOS) definition. The primary outcome of the UNyCORT study was the association between the donor's ECD/standard criteria donors (SCD) status and urinary complications at 1 year in uni- and multivariate analysis. Sub-group analysis, stratified analysis on ECD/SCD donor's status and transplant failure analysis were then conducted.

RESULTS

Between 1 January 2002 and 1 January 2018, 10 279 kidney transplants in adult recipients were recorded within the DIVAT network. A total of 8559 (83.4%) donors were deceased donors and 1699 (16.6%) were living donors (LD). Among donation after circulatory death (DCD) donors, 224 (2.85%) were uncontrolled DCD and 93 (1.09%) were controlled DCD donors. A total of 3617 (43.9%) deceased donors were ECD. The overall urological complication rate was 16.26%. The donor's ECD status was significantly associated with an increased risk of urological complications at 1 year in multivariate analysis (odds ratio: 1.50, 95% CI 1.31-1.71; P < 0.001) and especially with stenosis and ureteric fistulae at 1 year. There is no association with LD, uncontrolled and controlled DCD. The placement of an endo-ureteric stent was beneficial in preventing urinary complications in all donors and particularly in ECD donors.

CONCLUSION

The donor's ECD status is associated with a higher likelihood of stenosis and ureteric fistulae at 1 year. Recipients of grafts from ECD donors should probably be considered for closer urological monitoring and systematic preventive measures.

Ureteric Trauma following Stent Removal in Kidney Transplant Recipient: A Unique Case of Prolonged Morbidity

A 52-year-old African-American male patient with end-stage renal disease due to hypertension underwent deceased donor kidney transplant procedure with no immediate complications. The postprocedure complications, interventions, and course were abstracted by chart review. The ureteric stent was removed with flexible cystoscopy on postoperative day (POD) 24. 24 hours later, the patient presented with abdominal pain and inability to urinate. An urgent ultrasound and noncontrast CT scan showed grade 4 hydronephrosis of the transplanted kidney. A percutaneous nephrostomy stent was placed for urinary diversion. A large ureteric hematoma filling the lumen of the mid to distal ureter was identified on the nephrostogram and was evacuated. A follow-up nephrostogram on POD 44 revealed a distal ureter stricture and persistent well-formed midureter filling defect. A repeat nephrostogram performed at POD 72 was done with stricture dilatation, internalization of stents, and removal of a percutaneous nephrostomy tube. The patient was maintained on antibiotics for UTI prophylaxis throughout the course.

Tubeless percutaneous nephrolithotomy (PCNL) for forgotten and retained stent in renal allograft recipient: an interesting case report and lessons learnt

Complications after renal allograft transplantation are not so uncommon. Most complications are related to graft rejection, immune-suppressive drug toxicity and the operative procedure. Stents are placed after a transplant to prevent urine leak at the site of ureteric reimplantation, to facilitate an early healing in immune-suppressed individuals and to prevent obstruction at the site of ureteral anastomosis. We report a case of a renal allograft recipient with a forgotten ureteral double J stent. where the stent remained in situ for more than 4 years and further complicated by encrustation and stone formation at both the bladder and renal pelvic ends. The stone over the bladder coil was removed by holmium laser cystolithotripsy while the encrusted renal pelvic coil was removed by percutaneous approach. This case is presented for its rarity and also to emphasise on the need for maintenance of a stent register in order to ensure avoidance of such preventable complications.

Urological Complications in Kidney Transplant Recipients: Analysis of the Risk Factors and Impact on Transplant Outcomes in the Era of “Extended Criteria Donors”

Urological complications (UC) following kidney transplantation (KT) are associated with increased morbidity. The aim of this study is to evaluate the risk factors for UC in the era of “extended criteria donors” (ECD) and their impact on patient and graft survivals. A retrospective monocentric study of all patients undergoing KT from 2010 to 2019 with a follow-up ≥30 days was performed. Out of 459 patients (males: 296 (64.5%); age: 57 (19–77) years) enrolled, 228 (49.7%) received ECD organs, moreover, 166 (67.2%) grafts had a cold ischemia time ≥10 h. UCs were reported in 32 (7%) patients. In 21 (65.6%) cases UC occurred within 3 months post-KT and 24 (5.2%) were associated with early urinary tract infection (UTI). The overall 5 year patient and graft survival rates were 96.5% and 90.6%, respectively. UC decreased graft survival (UC-group: 75.0% vs. noUC-group: 91.8%, p < 0.001), especially if associated with early UTI (UC-group: 71.4% vs. noUC-group: 77.8%, p < 0.001). At multivariate analysis, early UTI after KT (OR: 9.975, 95%-IC: 2.934–33.909, p < 0.001) and delayed graft function (DGF) (OR: 3.844, 95%-IC: 1.328–11.131, p: 0.013) were significant risk factors for UC, while ECD graft did not increase the risk of post-transplant UC. ECD grafts are not associated with UC. DGF and early UTI post-KT increase the risks of UC and reduce graft survival in the long-term. Therefore, aggressive management of early post-transplant UTI and strategies to reduce DGF incidence, such as machine preservation, are essential to prevent UC after KT.

Risk Factors for Anastomosis Leakage After Kidney Transplantation

Purpose

Kidney transplantation is one of the best treatment options for end-stage renal disease with an incidence of urologic complications of 2.5 to 30%. One of the most serious and frequent urological complications is urinary leakage from ureteroneocystostomy anastomosis. The purpose of this study was to evaluate risk factors of urinary leakage from ureteroneocystostomy anastomosis after kidney transplantation.

Patients and Methods

A retrospective study was performed on patients who received kidney transplantation and were diagnosed with urinary leakage thereafter based on renal scan or drain creatinine per serum creatinine compared with patients in control group. Risk factor assessment was based on inpatient and outpatient information from hospital database.

Results

From 459 patients who received kidney transplantation in 2016-2018, there were 20 patients who were diagnosed with urinary leakage after they underwent ureteroneocystostomy anastomosis. The significant risk factors for anastomosis leakage were size of suture materials and duration of ureteral stent insertion. No statistically significant difference in other factors such as underlying disease, surgical technique or duration of urinary catheter was found. About overall urological complication, gender and body mass index significantly affected the outcome.

Conclusion

The rate of urinary leakage complications was found to be about 4.36%. The risk factors of overall complication comprised gender and body mass index. Although a lot of previous studies revealed many risk factors that could affect urinary leakage, size of suture materials and duration of ureteral stent insertion were the significant risk factors in our study. Proper consideration should be given to the size of suture materials and optimal duration of ureteral stent.

Comparison of a magnetic retrieval device vs. flexible cystoscopy for removal of ureteral stents in renal transplant patients: A randomized controlled trial

INTRODUCTION

Placement of a ureteral stent at the time of renal transplantation can reduce complications when compared to non-stented anastomoses. Removal by flexible cystoscopy can be associated with discomfort, risk for infection, and high costs. New magnetic stents offer a means of bypassing cystoscopy by use of a magnetic retrieval device. Our objective was to compare clinical and cost-related outcomes of conventional and magnetic stents in patients undergoing deceased donor renal transplantation.

METHODS

Patients were randomized to receive either a conventional or a Black-Star^® magnetic stent. Clinical, procedural, and cost outcomes were assessed, and the Ureteral Stent Symptom Questionnaire (USSQ) was administered with the stent in situ and after stent removal. All variables were compared between groups.

RESULTS

Forty-one patients were randomized to conventional (n=19) or Black-Star (n=22) stent. The total time for stent removal under cystoscopy was significantly longer compared to Black-Star removal (6.67±2.47 and 4.80±2.21 minutes, respectively, p=0.019). No differences were found in the USSQ domains between groups. Rates of urinary tract infections and surgical complications between groups were similar. Stent removal was well-tolerated in both groups. Black-Star stent use resulted in a cost savings of $304.02 Canadian dollars (CAD) per case.

CONCLUSIONS

USSQ scores suggest that stent removal with the Black-Star magnetic stent is as equally well-tolerated as flexible cystoscopy by renal transplant patients. Black-Star stent removal was significantly faster than conventional stents. No differences in discomfort, infection rate, or complication rate were found. Use of the Black-Star stent resulted in an estimated annual savings of $27 360 CAD at our centre.

Timely surgical intervention for ureteric complications ensures adequate graft function in renal transplantation: a 10-year review

BACKGROUND

Ureteric complications can cause significant morbidity in renal and simultaneous pancreas-kidney (SPK) transplantation. This 10-year review identified transplant patients with ureteric complications necessitating surgical intervention in an Australian tertiary centre.

METHODS

The hospital records were scrutinized in detail to identify all patients who underwent renal or SPK transplantation from 1 June 2009 to 31 May 2019 with subsequent surgical management of ureteric complications. A case series of patients with ureteric complications was generated and findings were analysed.

RESULTS

A total of 893 renal and SPK transplants were performed over the 10-year period. Ten of these (1.12%; seven renal and three SPK) had ureteric complications. All were managed surgically. Five of the 10 had ureteric leaks (0.56%); three had ureteric strictures (0.34%), one had ureteric obstruction from extraluminal compression (0.11%) and one had both leak and stricture (0.11%). All 10 patients underwent ureteric reimplantation. Two patients required more than one operation for their ureteric complication. No graft loss or surgical mortality occurred. All 10 patients currently have functioning kidney transplants and none require maintenance dialysis.

CONCLUSION

We report a low rate (1.12%) of ureteric complications in our renal and SPK transplants. Our standard practice of definitive correction by ureteric reimplantation is proving successful. The authors confirm that appropriate surgery is a viable and durable option in renal transplant patients with excellent graft outcomes.

Is peritoneal dialysis prior to kidney transplantation a risk factor for ureteral stenosis after adult to adult live kidney transplantation

Objectives

Major urinary complications such as urinary leaks, stenosis or urinary tract infections after kidney transplantation can lead to graft or patient loss. The effect of peritoneal dialysis on post-kidney transplantation complications have been discussed but its effect on ureteral stenosis is unknown. In this study, it was aimed to analyze factors effecting major ureteral complications after living donor kidney transplantation and impact of peritoneal dialysis and double J-stents (JJ stents).

Material and Methods

This study included 116 adult to adult living donor kidney transplant patients. Factors effecting major urologic complications after living donor kidney transplantation were analyzed. The donors were primary relatives of the recipients.

Results

Major urologic complications after living donor kidney transplantation was 8/116 (6.9%). Urinary leak was present in 2 (1.7%) patients. Ureteral stenosis was encountered in 6 (5.2%) patients. Double J stents were used in 84 (72.4%) of the cases. The effect of JJ ureteral stent was not statistically significant for urinary leak, ureteral stenosis (p= 0.074, p= 0.470, respectively). A total of 29 (25%) patients had peritoneal dialysis before kidney transplantation. Preoperative peritoneal dialyses and bacteriuria after kidney transplantation were independent risk factors for ureteral stenosis in multivariate analysis (p= 0.013, and p= 0.010 respectively).

Conclusion

In the guidance of the results of the present study, peritoneal dialysis prior to kidney transplantation and bacteriuria are independent risk factors for ureteral stenosis after living donor kidney transplantation. JJ stents have no effect on urologic complications after living donor kidney transplantation.

Results of Pediatric Kidney Transplants in an 8-Year Period: A Retrospective Study

BACKGROUND

Patient survival and quality of life is better after a kidney transplant compared with dialysis. In this retrospective study, we analyzed the results of pediatric kidney transplants in an 8-year period in our center.

METHODS

We reviewed the files of 166 children and adolescents who had undergone kidney transplants between 2008 and 2015 in our center. All the patients were younger than 18 years old and had been followed up for at least 2 years.

RESULTS

The transplanted kidneys were taken from live donors in 146 (88%) of the cases and from cadavers in 20 (12%) of the cases. They were procured from unrelated and related donors in 129 (90%) and 17 (10%) of the cases, respectively. Laparoscopic nephrectomy was done on 141 donors. The kidney vessels were anastomosed to the aorta, the common iliac, and the internal iliac in 3.6%, 56%, and 40.4% of cases, respectively. Preemptive kidney transplants were performed on 62 patients. The mean of patient survival was 124 ± 1.37 months. One- and five-year patient survival rates were 99% and 97%, respectively. The mean of graft survival was 118.29 ± 2.47 months. One- and five-year graft survival rates were 94% and 93%, respectively. Preemptive kidney transplants had a higher graft survival rate (P < .02).

CONCLUSION

Kidney transplant is a safe and feasible procedure in children and adolescents based on patient and graft survival outcomes. In our center, surgery complications led to kidney loss in very few cases.

An Update on Early Urological Complications in Kidney Transplantation: A National Cohort Study

<strong>BACKGROUND</strong> This study aimed to provide an update on the occurrence of early urological complications in living-donor and deceased-donor kidney transplantation (KTX). <strong>MATERIAL AND METHODS</strong> Data on all kidney transplant recipients in the Netherlands between January 2005 and December 2015 were retrieved from the prospectively collected Dutch National Organ Transplant Registry Database (NOTR). We assessed the incidence of major urological complications (MUCs) within 3 months after KTX, defined as urinary leakage and ureteral obstruction. Outcomes of living donor and deceased donor kidney transplants were compared. We performed regression analysis to identify predictive factors of urological complications and studied the influence of early urological complications on graft and patient survival. We performed an additional sub-study to explore the influence of preservation of the peri-ureteric connective tissue in living-donor KTX on the occurrence of urological complications. <strong>RESULTS</strong> Among 3329 kidney transplant recipients, urological complications occurred in 208 patients (6.2%) within 3 months after surgery. There were no significant differences in complication rates between recipients from living donors and deceased donors. Multiple regression analysis showed that older donor age and previous cardiac events of the recipient were predictors for the development of urological complications. Graft and patient survival were not affected by early MUCs. The additional sub-study showed that preservation of peri-ureteric tissue within living-donor KTX was not independently associated with urological complications. <strong>CONCLUSIONS</strong> Many living- and deceased-donor KTX recipients have early urological complications. MUCs did not affect long-term graft or patient survival.

Tubular Ectasia in Renal Allograft Biopsy: Associations With Occult Obstructive Urological Complications

BACKGROUND

Urological obstructive complications (UOC) affect up to 15% of kidney transplants (KTX). Most cases are excluded by ultrasonography (US); however, accuracy may be limited in the early transplant phase. Features of acute tubular injury (ATI) in KTX biopsy may be informative but histological features indicating UOC are ill defined. Tubular ectasia (TE) was shown to be associated with UOC in experimental data. We evaluated the association of histomorphological features, particularly TE, with occult (=without relevant hydronephrosis in US) UOC and renal outcomes.

METHODS

We included all recipients with an early indication biopsy (976 of 1537 consecutive KTX). The biopsy finding of TE classified as "suspicious of UOC" was compared with the following endpoints: delayed graft function, estimated glomerular filtration rate, and occult UOC. Additionally, histopathological features of ATI were reevaluated by a single pathologist to increase diagnostic accuracy.

RESULTS

Fifty-eight (5.9%) patients presented with TE, which was not related to delayed graft function or estimated glomerular filtration rate. Forty percent of patients had a UOC (most frequently ureteral stenosis) close to biopsy. Comparing these biopsies to matched controls, TE was significantly associated with UOC (odds ratio 2.69; P = 0.018). After histopathological reevaluation of these biopsies including additional features of ATI, we developed a final multivariate model with a highly significant relationship to UOC (Receiver operating characteristic-area under the curve: 0.77; P = 0.001). The model provides a specificity of 78% and negative predictive value of 73%.

CONCLUSIONS

TE together with additional signs of ATI indicates occult UOC. This histological phenotype should trigger more detailed evaluation for UOC when there is no evidence of relevant hydronephrosis in the ultrasonography.

Early urological complications after kidney transplantation: An overview

Urological complications, especially urine leaks, remain the most common type of surgical complication in the early post-transplant period. Despite major advances in the field of transplantation, a small minority of kidney transplants are still being lost due to urological problems. Many of these complications can be traced back to the time of retrieval and implantation. Serial ultrasound examination of the transplanted graft in the early post-operative period is of key importance for early detection. The prognosis is generally excellent if recognized and managed in a timely fashion. The purpose of this narrative review is to discuss the different presentations, compare various ureterovesical anastomosis techniques and provide a basic overview for the management of post-transplant urological complications.

Preoperative Risk Factors Associated With Urinary Complications After Kidney Transplantation

BACKGROUND

Only surgically irrelevant risk factors including sex, African-American ancestry, or exceptional U-stitch anastomosis have been identified to associate with urinary complications after kidney transplantation. The objective was to identify modifiable and nonmodifiable risk factors associated with urinary complications after kidney transplantation.

METHODS

A single-center study of 3,129 kidney transplants performed over 40 years was conducted to identify independent risk factors using χ² tests and logistic regression analysis.

RESULTS

We identified the quality of the transplant's ureter, cystographic abnormalities in the recipient, and repeat transplantations as independent risk factors for overall urinary complications occurring after kidney transplantation in multivariable analysis. Obesity was associated with an increased risk of urinary fistula, while the presence of a JJ stent was associated with a reduced risk of urinary fistula. The risk of urinary surgical complications for kidney transplantations was reduced when the kidney was recovered from a living related compared to a deceased donor.

CONCLUSIONS

The risk factors identified in the present study will allow candidates for kidney transplantation to be more informed and will also allow for surgical modifications to limit the occurrence of urinary complications.

Initial Experience in the Use of Novel Auto-expandable Metal Ureteral Stent in the Treatment of Ureter Stenosis in Kidney Transplanted Patients

INTRODUCTION

Ureter stenosis in renal transplantation patients is a relatively frequent complication that negatively conditions graft evolution. The use of ureteral stents is a valid treatment alternative to the use of double-J catheters in patients for whom surgery is not contemplated or after surgical recurrence. We present our initial experience with five patients treated using this technique.

MATERIALS AND METHODS

We describe a total of five patients with ureteral stenosis after renal transplantation who were treated using ureteral stent model UVENTA (Taewoong Medical, Seoul, Korea) in our center. The median follow-up was 18 months (range, 4 to 38 months). We describe the clinical history of patients and previous treatments on ureteral stenosis. The technical procedure of placement is described. The clinical course is analyzed by measurement of renal function and imaging tests, as well as post-stent complications. Survival of the renal graft is evaluated.

RESULTS

The procedure could be completed in all patients without complications. The technique was effective in all patients, with correction of creatinine value and hydronephrosis during the renal ultrasound test. One patient suffered a urinary tract infection episode associated with the use of the ureteral stent. One patient suffered the loss of the renal graft secondary to the development of cryoglobulins. One hundred percent of the ureteral stents are functioning as of the writing of this article.

CONCLUSIONS

In renal transplantation patients with ureter stenosis, metallic stents are a useful technique with low morbidity and associated complications.

Ureteral Stenosis After Renal Transplantation-A Single-Center 10-Year Experience

BACKGROUND

Kidney transplantation (KT) is the definitive treatment for ESRD. Ureteral stenosis (US) is one of the most common urologic complications and has been reported in 2.6%-15% of KTs.

METHODS

We reviewed data for 973 consecutive KT procedures performed at our center from January 2004 to September 2014, with evaluation of US management and recurrence rate.

RESULTS

The 973 KTs were performed with the use of the direct ureterovesical (UV) implantation Paquin technique, and the mean follow-up time was 44.3 ± 30.2 [range, 3-111] months. During this period, 33 cases of US (3.39%) were reported. The interval from KT to US diagnosis was 10.6 ± 23.0 (range, 0.5-98.0) months. The majority of the US cases were located in the distal ureter and UV junction (83.9%), with only 2 cases of middle ureter stenosis and 2 cases of ureteropelvic junction. Mean US length was 2.5 ± 1.9 (range, 1.0-10.0) cm. Surgical management and global and treatment-specific recurrence rates were reviewed. Primary surgical treatment recurrence rate was higher for the endoscopic approach, with a mean global time from treatment to US recurrence of 6.9 ± 16.3 (range, 0-65) months and a median of 2.0 months. Open surgical approach was the main recurrence treatment option (74%). There were 2 cases of graft loss. Success rate evaluation of overall and treatment-specific primary surgical management did not reveal significant differences (P > .05) according to stenosis length (<1.5, 1.5-3.0, or >3.0 cm), time between transplant and stenosis (≤3, 3-12, or >12 mo), or stenosis location (distal, middle, or upper ureter). However, there was clearly a trend to higher success rate in smaller stenosis (<1.5 cm) and early management (≤3 mo), particularly with the use of balloon dilation.

CONCLUSIONS

US management should be decided on a case-by-case basis according to clinical characteristics, treatment-specific recurrence rate, and previous surgical options.

Timing and Predictors of Early Urologic and Infectious Complications After Renal Transplant: An Analysis of a New York Statewide Database

OBJECTIVES

The most common complications after renal transplant are urologic and are a cause of significant morbidity in a vulnerable population. We sought to characterize the timing and predictors of urologic complications after renal transplant using a statewide database.

MATERIALS AND METHODS

We queried the New York Statewide Planning and Research Cooperative System database to identify patients who underwent renal transplant from 2005 to 2013. Postoperative complications included hydronephrosis, ureteral stricture, vesicoureteral reflux, nephrolithiasis, and urinary tract infections. Cox proportional hazards model was used to assess independent predictors of urologic complications.

RESULTS

In total, 9038 patients were included in the analyses. Urologic complications occurred in 11.3% of patients and included hydronephrosis (12.0%), nephrolithiasis (2.8%), ureteral stricture (2.4%), and vesicoureteral reflux (1.5%). We found that 23% experienced at least one urinary tract infection. On multivariate analysis, predictors of urologic complications included medicare insurance, hypertension, and prior urinary tract infection. Graft recipients from living donors were less likely to experience urologic complications than deceased-donor kidney recipients (P < .001).

CONCLUSIONS

Urologic complications occur in a significant proportion of renal transplants. Further study is needed to identify risk factors for complications after renal transplantation to decrease morbidity in this vulnerable population.

Atrophic bladder in long-term dialysis patients increases the risk for urological complications after kidney transplantation

OBJECTIVES

To evaluate the risk for urological complications after kidney transplantation at a single medical center in Japan.

METHODS

In the present study, 408 kidney recipients (255 men, 153 women) were enrolled. There were 349 living and 59 deceased donors. The average age of the recipients was 42.5 ± 13.5 years, and the average pretransplant dialysis period was 71.8 ± 88.2 months. Ureteroneocystostomy was carried out on 347 patients, and ureteroureterostomy on 61 patients. We investigated the relationship between pretransplant duration of dialysis and bladder capacity, and examined the risk factors for urological complication. We also evaluated the incidence of vesicoureteral reflux in 191 recipients who underwent ureteroneocystostomy during transplantation.

RESULTS

The preoperative duration of dialysis therapy showed a significant negative correlation with bladder capacity (R²  = 0.33, P < 0.001). The overall urological complication rate was 3.4% (14 patients), including urinary leakage (12 patients) and ureteral stricture (two patients). Univariate analysis showed that atrophic bladder, long-term dialysis therapy, deceased donor and ureteroureterostomy were associated with a higher incidence of urological complications (odds ratio 8.05, 4.43, 3.42 and 3.35; P < 0.01, P = 0.01, P = 0.04 and P = 0.04, respectively). Furthermore, multivariate analysis showed that atrophic bladder was the only significant factor associated with urological complications (odds ratio 10.37; P = 0.01). Among 191 recipients, vesicoureteral reflux was observed in 32 (16.8%). The incidence of vesicoureteral reflux was significantly higher in patients with atrophic bladder.

CONCLUSIONS

Bladder atrophy in renal transplant recipients after long-term dialysis therapy is associated with a higher risk of urological complications.

Percutaneous removal of impacted double J stent in a transplant kidney

Prophylactic double J (DJ) stent insertion has been adopted as a routine procedure in renal transplant patients for internal urinary diversion and for protecting ureteroneocystostomy anastomosis. The timely and early removal of stent has been proved to reduce the occurrence of stent-associated complications such as migration, encrustation, and infection. The most commonly used procedure of stent removal via retrograde cystoscopic approach can sometimes be technically very difficult leaving antegrade approach as another alternative to open surgery as the last resort. Here, we describe a case of antegradely removed impacted DJ stent by pushing it free into the urinary bladder followed by cystoscopic removal.

Understanding Inpatient Cost Variation in Kidney Transplantation: Implications for Payment Reforms

OBJECTIVE

To examine the magnitude and sources of inpatient cost variation for kidney transplantation.

METHODS

We used the 2005-2009 Nationwide Inpatient Sample to identify patients who underwent kidney transplantation. We first calculated the patient-level cost of each transplantation admission and then aggregated costs to the hospital level. We fit hierarchical linear regression models to identify sources of cost variation and to estimate how much unexplained variation remained after adjusting for case-mix variables commonly found in administrative datasets.

RESULTS

We identified 8866 living donor (LDRT) and 5589 deceased donor (DDRT) renal transplantations. We found that higher costs were associated with the presence of complications (LDRT, 14%; P <.001; DDRT, 24%; P <.001), plasmapheresis (LDRT, 27%; P <.001; DDRT, 27%; P <.001), dialysis (LDRT, 4%; P <.001), and prolonged length of stay (LDRT, 84%; P <.001; DDRT, 82%; P <.001). Even after case-mix adjustment, a considerable amount of unexplained cost variation remained between transplant centers (DDRT, 52%; LDRT, 66%).

CONCLUSION

Although significant inpatient cost variation is present across transplant centers, much of the cost variation for kidney transplantation is not explained by commonly used risk-adjustment variables in administrative datasets. These findings suggest that although there is an opportunity to achieve savings through payment reforms for kidney transplantation, policymakers should seek alternative sources of information (eg, clinical registry data) to delineate sources of warranted and unwarranted cost variation.

Outcome of kidney transplant with double ureter: a multicenter study

OBJECTIVES

Renal transplant with double ureters is uncommon. However, with increasing numbers of en bloc and dual transplants from marginal donors, we frequently observe 2 ureters for implant. The current study reviewed our experience with 76 double-ureter renal transplants.

MATERIALS AND METHODS

We performed a retrospective analysis of renal transplant performed in 2 institutes from 1996 to 2011. We recorded the outcomes of renal transplants with double ureters including complications. We compared outcomes with renal transplants with single ureters.

RESULTS

Irrespective of the technique used for implant, we recorded no significant risk of complications of double, compared with single, ureter renal transplants. There were no significant differences in patient and graft survival.

CONCLUSIONS

We believe that double-ureter transplant does not require additional risk discussion with the recipient because it is safe. However, when ureteral stents are used, we should ensure that a mechanism is in place for both stents to be removed postoperatively.

Independent risk factors for early urologic complications after kidney transplantation

Urologic complications are the most frequent technical adverse events following kidney transplantation (KTX). We evaluated traditional and novel potential risk factors for urologic complications following KTX. Consecutive KTX recipients between December 1, 2006 and December 31, 2010 with at least six-month follow-up (n = 635) were evaluated for overall urologic complications accounting for donor, recipient, and transplant characteristics using univariate and multivariate logistic regression. Urologic complications occurred in 29 cases (4.6%) at a median of 40 d (range 1-999) post-transplantation and included 17 ureteral strictures (2.6%), five (0.8%) ureteral obstructions due to donor-derived stones or intraluminal thrombus, and seven urine leaks (1.1%). All except two complications occurred within the first year of transplantation. Risk factors for urologic complications on univariate analysis were dual KTX (p = 0.04) and renal artery multiplicity (p = 0.02). On multivariate analysis, only renal artery multiplicity remained significant (aHR 2.4, 95% confidence interval 1.1, 5.1, p = 0.02). Donation after cardiac death, non-mandatory national share kidneys, donor peak serum creatinine > 1.5 mg/dL or creatinine phosphokinase > 1000 IU/L, and donor down time were not associated with urologic complications. Our data suggest that donor artery multiplicity is an independent risk factor for urologic complications following KTX.

Removal of foley catheters in live donor kidney transplant recipients on postoperative day 1 does not increase the incidence of urine leaks

Catheterization of the urinary bladder during kidney transplantation is essential. The optimal time to remove the Foley catheter postoperatively is not universally defined. It is our practice to remove the Foley catheter on postoperative day 1 in live donor kidney transplant recipients who meet our standardized protocol criteria. We believe that early removal of Foley catheters increases patient comfort and mobility, decreases the risk of catheter associated urinary tract infections, and allows for decreased hospital length of stay. The hypothetical risk of early removal of Foley catheters would be the increased risk of urine leak. We reviewed 120 consecutive live donor kidney transplant recipients and found that there was not an increased incidence of urine leaks in patients whose Foley catheters were removed on postoperative day 1.

Classification of ureteral stenosis and associated strategy for treatment after kidney transplant

OBJECTIVES

Ureteral stenosis is a common complication after a kidney transplant. Treatment for ureteral stenosis ranges from interventional procedures to open surgery. The aim of this study is to present classification for ureteral stenosis and recommend the targeted strategy for effective treatment.

MATERIALS AND METHODS

Twelve cases of ureteral stenosis were diagnosed among 193 kidney transplants, of which 91 were from a live donor and 102 from a deceased donor. The mean age was 46.22 ± 13.23 years. The diagnosis of ureteral stenosis includes serum creatinine elevation, hydronephrosis, and presence of stricture on a pyelogram. The criterion for classification is based on the severity of stricture.

RESULTS

One of ureteral stenoses was classified as grade 1, six were grade 2, and five were grade 3. Of 12 cases, 10 were live-donor kidney transplant, 4 had lymphocele, and 2 had a hematoma after transplant. The corresponding strategy for each grade of ureteral stenosis is as follows: grade 1, ureteral stent reinsertion; grade 2, cutting balloon dilatation or endoscopic incision of stenosis; grade 3, open surgery urinary tract reconstruction. All cases were successfully treated using these strategies.

CONCLUSIONS

This classification of ureteral stenosis provides guidance for effective management and avoids unnecessary procedures. In this series, ureteral stenosis was significantly associated with a live donor and surgical complications.

Impact of surgeon experience on complication rates and functional outcomes of 484 deceased donor renal transplants: a single-centre retrospective study

OBJECTIVE

To determine how postoperative and functional outcomes after deceased donor renal transplantation (DDRT) are related to surgeon experience.

PATIENTS AND METHODS

The outcomes of 484 adult DDRT performed by 13 urological surgeons were retrospectively reviewed. After completion of a staged renal transplant training programme under supervision of an attending urological transplant surgeon, the 13 surgeons were either assigned to the inexperienced group (n = 8) or the experienced group (n = 5). Surgeons in the experienced group had performed more than 30 unsupervised DDRT in a standard fashion with routine ureteric stenting. Between 1988 and 2005, inexperienced surgeons performed 152 DDRT, whereas experienced surgeons performed 332 DDRT.

RESULTS

Patient and graft survival at 2 hyears were 98% and 94.7%, respectively. Early graft loss in five recipients was unrelated to surgeon experience. Delayed graft function occurred in 29% of cases and median 1-year serum-creatinine was 1.48 mg/dL, with no difference between surgeon groups. Postoperative bleeding and lymphocele formation were the most frequent surgical complications, with an equal distribution between groups. Ureteric complications had a significantly higher incidence among inexperienced surgeons (6.6% versus 2.7%; P = 0.04).

CONCLUSION

We conclude that DDRT as performed by inexperienced urological renal transplant surgeons has both acceptable short- and long-term outcomes.

Transplant ureter should be stented routinely

Vesicoureteric complications present early after transplantation and contribute to patient morbidity, graft loss and mortality. Ureteral stenting provides a decrease in ureteroneocystostomy anastomotic complications following renal transplantation. There should be prophylactic stent insertion with endoscopic removal at a designated time post transplantation. With the addition of antibiotic prophylaxis post transplantation, ureteric stenting does not increase the rate of urinary tact infections. There is no significant increase in cost for stenting during transplantation in comparison to management of major ureteric complications. Routine stenting causes significant cost-saving per year and prevents anastomotic complications. It is wise to stent the transplant ureter routinely.

Extraperitoneal urine leak after renal transplantation: the role of radionuclide imaging and the value of accompanying SPECT/CT - a case report

BACKGROUND

The differentiation of the nature of a fluid collection as a complication of kidney transplantation is important for management and treatment planning. Early and delayed radionuclide renography can play an important role in the evaluation of a urine leak. However, it is sometimes limited in the evaluation of the exact location and extent of a urine leak.

CASE PRESENTATION

A 71-year-old male who had sudden anuria, scrotal swelling and elevated creatinine level after cadaveric renal transplantation performed Tc-99 m MAG3 renography to evaluate the renal function, followed by an ultrasound which was unremarkable. An extensive urine leak was evident on the planar images. However, an exact location of the urine leak was unknown. Accompanying SPECT/CT images confirmed a urine leak extending from the lower aspect of the transplant kidney to the floor of the pelvic cavity, presacral region and the scrotum via right inguinal canal as well as to the right abdominal wall.

CONCLUSIONS

Renal scintigraphy is very useful to detect a urine leak after renal transplantation. However, planar imaging is sometimes limited in evaluating the anatomical location and extent of a urine leak accurately. In that case accompanying SPECT/CT images are very helpful and valuable to evaluate the anatomical relationships exactly.

Therapeutic option for infected urinary tract fistulas in renal transplantation

BACKGROUND

Approximately 20% of urinary tract fistulas after renal allografting are complicated by urinary tract infection, which presents a therapeutic challenge.

OBJECTIVE

To evaluate an option for treatment of urinary tract fistulas associated with urinary tract infection and unsuitable for minimally invasive or primary surgical urinary tract repair.

PATIENTS AND METHODS

The study included 650 recipients who underwent transplantation over 17 years. Urinary leakage was initially treated with indwelling bladder catheterization. Patients with fistulas refractory to treatment underwent surgical intervention to repair the urinary tract. In patients who were not candidates for primary repair of the urinary tract, temporary urinary diversion was performed, rather than classic percutaneous or open nephrostomy, using a ureteral stent (ie, a 6F or 8F Foley catheter with the balloon placed inside the renal pelvis).

RESULTS

Overall, urinary leakage occurred in 36 patients (5.5%). Conservative management was successful in 14 vesical fistulas (42.4%) and no ureteral fistulas (0%). Three patients died of sepsis during conservative treatment, before the new surgical approach. Five of 36 urinary leaks (13.9%) were managed using ureteral intubation with an 8F Foley catheter, with a success rate of 80%.

CONCLUSION

Ureteral catheterization with an 8F Foley catheter is a feasible therapeutic option to treat complicated urinary tract fistulas unsuitable for primary surgical repair of the urinary tract.

Risk factors and treatment success for ureteral obstruction after pediatric renal transplantation

PURPOSE

Risk factors and treatment efficacy for ureteral obstruction following pediatric renal transplantation are poorly understood. We describe a single center experience with pediatric transplant recipients in an effort to discern risk factors and treatment efficacy.

MATERIALS AND METHODS

We retrospectively reviewed the pediatric renal transplant database at our institution from January 1984 to March 2008. Donor and recipient demographics, treatment indications, graft characteristics, surgical techniques, treatment course, complications and graft outcomes were abstracted from clinical records.

RESULTS

A total of 449 children (mean age 8.6 years) who underwent 526 renal transplants were included in the study. Ureteral obstruction requiring intervention developed in 42 cases (8%). Recipient age and gender, recipient and donor race, donor harvest technique, ureterovesical anastomosis with or without stenting, number of donor arteries, number of human leukocyte antigen mismatches, prior renal transplant and ischemia time were not significantly associated with increased incidence of ureteral obstruction. Renal failure secondary to posterior urethral valves was the only parameter significantly associated with increased incidence of ureteral obstruction (univariate OR 4.93, p = <0.0001; multivariate point estimate 7.59, p <0.0001). Of patients with ureteral obstruction 48% presented within 100 days after transplant. Kaplan-Meier analysis showed significantly decreased ureteral obstruction-free survival in patients with vs without posterior urethral valves (log rank test, p <0.0001). Ureteral obstruction, stenting and dilation were not significantly associated with increased graft loss or patient death.

CONCLUSIONS

Ureteral obstruction after renal transplantation in children is a challenging complication that demands clinical vigilance. Posterior urethral valves appear to be a significant risk factor for post-transplant ureteral obstruction likely due to local factors such as ischemia, thick bladder wall and collagen remodeling.

Case mix, quality and high-cost kidney transplant patients

A better understanding of high-cost kidney transplant patients would be useful for informing value-based purchasing strategies by payers. This retrospective cohort study was based on the Medicare Provider Analysis and Review (MEDPAR) files from 2003 to 2006. The focus of this analysis was high-cost kidney transplant patients (patients that qualified for Medicare outlier payments and 30-day readmission payments). Using regression techniques, we explored relationships between high-cost kidney transplant patients, center-specific case mix, and center quality. Among 43 393 kidney transplants in Medicare recipients, 35.2% were categorized as high-cost patients. These payments represented 20% of total Medicare payments for kidney transplantation and exceeded $200 million over the study period. Case mix was associated with these payments and was an important factor underlying variation in hospital payments high-cost patients. Hospital quality was also a strong determinant of future Medicare payments for high-cost patients. Compared to high-quality centers, low-quality centers cost Medicare an additional $1185 per kidney transplant. Payments for high-cost patients represent a significant proportion of the total costs of kidney transplant surgical care. Quality improvement may be an important strategy for reducing the costs of kidney transplantation.