Urologic complications in renal transplants

Optimizing the kidney donor pool: transplanting donor kidneys after partial nephrectomy of masses or cysts

Background

A limiting factor in expanding the kidney donor pool is donor kidneys with renal tumors or cysts. Partial nephrectomy (PN) to remove these lesions prior to transplantation may help optimize organ usage without recurrence of malignancy or increased risk of complications.

Methods

We retrospectively analyzed all recipients of a living or deceased donor graft between February 2009 and October 2022 in which a PN was performed prior to transplant due to the presence of one or more concerning growths. Donor and recipient demographics, perioperative data, donor allograft pathology, and recipient outcomes were obtained.

Results

Thirty-six recipients received a graft in which a PN was performed to remove suspicious masses or cysts prior to transplant. Majority of pathologies turned out to be a simple renal cyst (65%), followed by renal cell carcinoma (15%), benign multilocular cystic renal neoplasm (7.5%), angiomyolipoma (5%), benign renal tissue (5%), and papillary adenoma (2.5%). No renal malignancy recurrences were observed during the study period (median follow-up: 67.2 months). Fourteen complications occurred among 11 patients (30.6% overall) during the first 6mo post-transplant. Mean eGFR (± standard error) at 36 months post-transplant was 51.9 ± 4.2 ml/min/1.73 m2 (N = 23). Three death-censored graft losses and four deaths with a functioning graft and were observed.

Conclusion

PN of renal grafts with suspicious looking masses or cysts is a safe option to optimize organ usage and decrease the kidney non-use rate, with no observed recurrence of malignancy or increased risk of complications.

Current Evidence on Surgical Management for Benign Prostatic Hyperplasia in Renal Transplant Recipients: A Systematic Review

Background: Patients who have undergone renal transplant may have a concomitant benign prostatic hyperplasia (BPH), a condition that can potentially hinder the recovery of the renal graft and necessitate surgical intervention. However, endoscopic treatment of BPH should be performed carefully because of the associated perioperative risks. We aimed to systematically assess the factors affecting surgical indications and perioperative outcomes of BPH surgical treatment in renal transplantation (RT) recipients. Methods: A systematic literature search was performed on January 28, 2023, using Scopus, PubMed, and EMBASE with no date limit. Preclinical and animal studies, reviews, letters to the editor, case reports, and meeting abstracts were excluded. Results: Eighteen articles were accepted and included. Clinical BPH has a high incidence rate after RT, particularly in elderly men. Secondary events associated with BPH, such as acute urinary retention and urinary tract infections, can lead to a gradual decline of renal graft function and patient survival. BPH procedure can prevent these events and guarantee improvements in serum creatinine levels, voiding parameters, and lower urinary tract symptoms. When the urine culture is negative, the endoscopic procedure of the prostate may be performed within 1 month of the initial procedure, particularly in older patients, more prone to develop voiding dysfunction. Alternatively, a transurethral incision of the prostate may be recommended for patients with smaller prostates who wish to preserve ejaculatory function. Data on comparative BPH surgical procedures are lacking. Conclusions: BPH procedure should be offered in RT recipients who develop bladder outlet obstruction owing to BPH. Endoscopic treatment should be performed after a few weeks from RT to avoid further graft deterioration.

Ureteral Stenosis and Fistula after Kidney Transplantation

INTRODUCTION

Ureteral complications after kidney transplantation are frequent and may have a negative impact on morbidity and graft function. Treatment modalities include conservative, endourological, and surgical techniques, with variable outcomes. The purpose of this study was to report the incidence, characteristics, treatment, and outcomes of ureteral complications at our center.

METHODS

Retrospective study of kidney transplants performed at our unit between 2015 and 2020, analyzing incidence, characteristics, treatment, and outcomes of ureteral stenoses and fistulas.

RESULTS

Of 648 kidney transplants, we present 3.24% stenosis and 2.16% ureteral fistulas, with a mean time from transplantation of 101.4 and 24.4 days, respectively. Primary treatment was open surgical repair in 52.4% stenosis and 100% fistulas, with a success rate of 90.9% and 71.4%, respectively. Anterograde balloon dilatations were performed in 33.3% of stenosis with 40% success. Three patients required surgery as a secondary approach with 100% success. Major complications (Clavien-Dindo III) were observed in 18.5% following surgical repair. After a mean follow-up of 31.1 ± 20.9 months, we observe 88.6% of functioning grafts. We found no significant differences in graft survival between patients with or without ureteral complications (p 0.948).

CONCLUSION

Surgical repair of ureteral complications offers satisfactory results with low associated morbidity. Endourological techniques are less effective and should be reserved for selected cases. With adequate management, there is no impact on graft survival.

Risk Factors for Urologic Complications After Kidney Transplantation and Impact in Graft Survival

Background and Purpose

Kidney transplantation (KT) is the best therapy for chronic kidney disease (CKD). Major urologic complications (MUCs) are the second etiology associated to morbidity and graft loss following KT, after rejection episodes. The objective of this study was to estimate the incidence, risk factors and impact on graft survival associated to urological complications in KT patients.

Patients and Methods

A retrospective cohort based on electronic patient files of kidney transplant recipients from Colombiana de Trasplantes was created for the period August 2008 to September 2019. Initiation of follow-up was defined as the date of transplantation up to 3 years post-transplantation. Incidence of ureteral stenosis, ureteral obstruction, and ureteral leak was measured. A logistic regression multivariate model was adjusted to determine the associated factors to MUCs (yes/no). Patient and graft survival time were analyzed using a Kaplan-Meier method.

Results

A total of 1584 KT patients were included in the cohort. MUCs were present in 195 (12.6%) KT patients. We found that dialysis duration (OR: 1.004; p = 0.02) remained significant for the incidence of MUCs in KT patients of deceased donors. Probability of graft and patient survival at 3 years of follow-up was 90.5% and 85.5%, respectively. No significant difference was found on graft and patient survival in KT patients with or without MUCs.

Conclusion

MUCs are frequent complications for KT. We did not observe significant differences in graft or patient survival according to the presence of MUCs. The identification of MUCs and risk factors may guide transplant teams for future surgical and clinical decisions.

Partial Nephrectomy of Transplanted Kidney with Calyceal Fistula

Kidney transplant is the established treatment for patients with chronic kidney disease but is associated with complications due to the complexity of the procedure. Calyceal fistulas are rare urological complications in transplants caused by arterial occlusion with segmental infarction of the graft. Treatment is based on the extension of the affected area and the clinical status of the patient. For extensive infarctions treated surgically, a total nephrectomy of the transplanted kidney is generally performed. We present a case of a transplanted kidney with polar necrosis and calyceal fistula treated with partial nephrectomy of the affected area, maintaining the graft and preserving kidney function.

Transplant Ureteral Stenosis after Renal Transplantation: Risk Factor Analysis

INTRODUCTION

The results of kidney transplants have improved dramatically in recent years, leading to reduced morbidity and mortality. Despite continuous improvements, urological complications occur at a rate of 2.6%-15%. Ureteral stenosis of graft ureters is the most common complication, with a probability of 0.5%-6.3%. This study aimed to determine the incidence of ureteral stenosis after kidney transplantation and identify risk factors that distinguish transplant patients with and without ureteral stenosis.

METHODS

This study retrospectively analyzed patients who had undergone kidney transplantation at the Department of Urology of the Friedrich-Alexander University Erlangen-Nuremberg between 2001 and 2015. Forty-seven patients developed ureteral stenosis during the operation. Most of the ureteral stenosis cases occurred in the first 4 months after transplantation. Kaplan-Meier analysis and the log-rank test were used to calculate the cumulative risk, and the Mann-Whitney U test was used nonparametrically. The significance level was set at p < 0.05.

RESULTS

Statistical analysis showed that residual diuresis (p = 0.008), cold ischemia time (CIT) (p = 0.040), the body mass index (p = 0.027), and donor serum creatinine value (p = 0.039) showed a significantly different distribution between recipients with or without ureteral stenosis after kidney transplantation. In multivariate Cox's regression modeling, residual diuresis and the donor serum creatinine level were identified as the only independent predictors of patients' stenosis-free survival.

CONCLUSION

Urological complications not diagnosed and treated in time endanger the success of kidney transplantation. After evaluating the kidney transplantation data of the patients at the Transplant Center Erlangen-Nuremberg from 2001 to 2015, residual diuresis, CIT, the body mass index, and donor serum creatinine value were found to influence the development of ureteral stenosis.

The utility of native ureter in the management of ureteral complications in children after renal transplantation

BACKGROUND

Ureteral complications after renal transplantation in children are a major source of morbidity. Management is complex and variable.

METHODS

With IRB approval, health records were retrospectively reviewed of patients who: were <18 years, underwent kidney transplant between 1997 and 2017, had at least 2 years of follow-up, and underwent interventions due to post-transplant ureteral complications.

RESULTS

Of 136 patients, seventeen (13%) required ureteral intervention due to stricture (n = 3), reflux (n = 12), or both (n = 2). Transplant occurred at median 10.5 years (3.1-14.7). Reconstruction occurred at median 10 months (7-15) after transplant. Pre-existing bladder pathology was present in 6 (35%) patients. Four of five patients with strictures had at least one endoscopic balloon dilation. Ultimate management included reimplantation, ureteroureterostomy of native to transplant ureter, pyeloureterostomy to native ureter, multiple endoscopic interventions followed by a Boari flap, or multiple failed endoscopic interventions. Fourteen patients with VUR underwent reimplantation (n = 5), ureteroureterostomy of native to transplant ureter (n = 4), pyeloureterostomy to native ureter (n = 4), and one underwent endoscopic injection with Deflux of the transplant ureter. Only one patient had a non-functioning graft due to ureteral complication. All patients were alive at follow-up (median 17 years [12-19]).

CONCLUSIONS

Transplant ureteral reflux and stricture are significant complications following pediatric renal transplantation and may require surgical management. In our population, reflux or stricture requiring ureteral reconstruction occurred in 10% and 4%, respectively. Endoscopic interventions were rarely successful. Native ureters were used for ureteral reconstruction in more than two thirds of patients should be considered in management of ureteral complications.

Management of a ureteric stricture post ureteroileal anastomosis of a renal transplant

A 58-year-old woman with a prior radical cystectomy and ileal conduit underwent a living-related donor renal transplant for end-stage renal disease secondary to autoimmune glomerulonephritis. She subsequently developed an ischaemic stricture of the transplant ureter. A successful ureteropyelostomy was performed with the native right ureter anastomosed to the pelvis of the renal transplant. She presented to the emergency department 18 months later feeling unwell and with raised inflammatory markers. Imaging demonstrated a large soft tissue mass over the right psoas muscle and hydronephrosis of the native right kidney. A nephrostomy and nephrostogram of the native right kidney diagnosed a urine leak from the native right kidney and she underwent an open right native nephrectomy. She recovered well postoperatively and continues to have excellent graft function. Renal transplantation in an abnormal urinary tract carries a high risk of complications. A multidisciplinary team approach is essential in offering the most appropriate treatment and ensuring good graft function is preserved.

Imaging findings of en bloc simultaneous liver-kidney transplantation

Simultaneous liver-kidney transplantations (SLKTs) are increasing in incidence, and the en bloc surgical approach is associated with a unique spectrum of vascular complications. En bloc SLKTs have a common arterial supply from the celiac axis and post-operative assessment with Doppler ultrasound can help to localize vascular lesions as either proximal in the shared arterial supply or distal in the organ-specific arteries. Venous complications predominantly include thrombosis or stenosis of the portal vein, hepatic veins, renal vein, or IVC, but have a much lower incidence. Radiologists familiar with the post-operative anatomy and complications can provide meaningful and accurate assessment to help direct clinical care. The purpose of this article is to provide a targeted review of SLKT, review the post-surgical anatomy associated with en bloc SLKT, and review the imaging evaluation of vascular complications associated with SLKT.

Egyptian clinical practice guideline for kidney transplantation

Objective: To present the first Egyptian clinical practice guideline for kidney transplantation (KT).

Methods: A panel of multidisciplinary subspecialties related to KT prepared this document. The sources of information included updates of six international guidelines, and review of several relevant international and Egyptian publications. All statements were graded according to the strength of clinical practice recommendation and the level of evidence. All recommendations were discussed by the panel members who represented most of the licensed Egyptian centres practicing KT.

Results: Recommendations were given on preparation, surgical techniques and surgical complications of both donors and recipients. A special emphasis was made on the recipient’s journey with immunosuppression. It starts with setting the scene by covering the donor and recipient evaluations, medicolegal requirements, recipient’s protective vaccines, and risk assessment. It spans desensitisation and induction strategies to surgical approach and potential complications, options of maintenance immunosuppression, updated treatment of acute rejection and chemoprophylactic protocols. It ends with monitoring for potential complications of the recipient’s suppressed immunity and the short- and long-term complications of immunosuppressive drugs. It highlights the importance of individualisation of immunosuppression strategies consistent with pre-KT risk assessment. It emphasises the all-important role of anti-human leucocyte antigen antibodies, particularly the donor-specific antibodies (DSAs), in acute and chronic rejection, and eventual graft and patient survival. It addresses the place of DSAs across the recipient’s journey with his/her gift of life.

Conclusion: This guideline introduces the first proposed standard of good clinical practice in the field of KT in Egypt.

Abbreviations: Ab: antibody; ABMR: Ab-mediated rejection; ABO: ABO blood groups; BKV: BK polyomavirus; BMI: body mass index; BTS: British Transplantation Society; CAN: chronic allograft nephropathy; CDC: complement-dependent cytotoxicity; CKD: chronic kidney disease; CMV: cytomegalovirus; CNI: calcineurin inhibitor; CPRA: Calculated Panel Reactive Antibodies; (dn)DSA: (de novo) donor-specific antibodies; ECG: electrocardiogram; ESWL: extracorporeal shockwave lithotripsy; FCM: flow cytometry; GBM: glomerular basement membrane; GN: glomerulonephritis; HIV: human immunodeficiency virus; HLA: human leucocyte antigen; HPV: human papilloma virus; IL2-RA: interleukin-2 receptor antagonist; IVIg: intravenous immunoglobulin; KT(C)(R): kidney transplantation/transplant (candidate) (recipient); (L)(O)LDN: (laparoscopic) (open) live-donor nephrectomy; MBD: metabolic bone disease; MCS: Mean channel shift (in FCM-XM); MFI: mean fluorescence intensity; MMF: mycophenolate mofetil; mTOR(i): mammalian target of rapamycin (inhibitor); NG: ‘not graded’; PAP: Papanicolaou smear; PCN: percutaneous nephrostomy; PCNL: percutaneous nephrolithotomy; PKTU: post-KT urolithiasis; PLEX: plasma exchange; PRA: panel reactive antibodies; PSI: proliferation signal inhibitor; PTA: percutaneous transluminal angioplasty; RAS: renal artery stenosis; RAT: renal artery thrombosis;:rATG: rabbit anti-thymocyte globulin; RCT: randomised controlled trial; RIS: Relative MFI Score; RVT: renal vein thrombosis; TB: tuberculosis; TCMR: T-cell-mediated rejection; URS: ureterorenoscopy; (CD)US: (colour Doppler) ultrasonography; VCUG: voiding cystourethrogram; XM: cross match; ZN: Ziehl–Neelsen stain

Predictive Model of Ureteral Obstruction of Allograft Kidney Following Living Donor Kidney Transplantation

BACKGROUND

Ureteral obstruction is one of the most frequent urologic complications of kidney transplantation. This study aimed to analyze independent factors that contribute to ureteral obstruction following kidney transplantation and develop predictive models form those factors.

METHODS

As many as 545 kidney transplantations were analyzed. Patients underwent transplantation between January 2014 and December 2018. Logistic regression analysis was used to develop the predictive model. Both donor and recipient demographic characteristics and operative parameters were analyzed and presented.

RESULTS

There were 37 (6.8%) subjects who developed ureteral obstruction. The independent risk factors for ureteral obstruction were multiple allograft renal arteries, older donor ages (>38 years), and older recipient age (>60 years). From the receiver operating characteristic (ROC) curve analysis, the area under the ROC curve of the predictive model was 0.843 (P < .001). Subjects with >2 renal allograft arteries, recipient age >60 years, and donor age >38 years had 83.8% probability of developing ureteral stenosis after kidney transplantation.

CONCLUSION

Donor age, recipient age, and multiple renal arteries were independent risk factors of graft ureteral obstruction. Probability of developing ureteral obstruction should be considered pre-operatively in our population, using the proposed predictive model.

MRI for diagnosis of post-renal transplant complications: current state-of-the-art and future perspectives

Kidney transplantation has developed into a widespread procedure to treat end stage renal failure, with transplantation results improving over the years. Postoperative complications have decreased over the past decades, but are still an important cause of morbidity and mortality. Early accurate diagnosis and treatment is the key to prevent renal allograft impairment or even graft loss. Ideally, a diagnostic tool should be able to detect post-transplant renal dysfunction, differentiate between the different causes and monitor renal function during and after therapeutic interventions. Non-invasive imaging modalities for diagnostic purposes show promising results. Magnetic resonance imaging (MRI) techniques have a number of advantages, such as the lack of ionizing radiation and the possibility to obtain relevant tissue information without contrast, reducing the risk of contrast-induced nephrotoxicity. However, most techniques still lack the specificity to distinguish different types of parenchymal diseases. Despite some promising outcomes, MRI is still barely used in the post-transplantation diagnostic process. The aim of this review is to survey the current literature on the relevance and clinical applicability of diagnostic MRI modalities for the detection of various types of complications after kidney transplantation.