Long-term clinical impact of vesicoureteral reflux in kidney transplantation

Surgical and Infectious Complications Following Kidney Transplantation: A Contemporary Review

Kidney transplantation significantly improves outcomes in patients with end-stage renal disease; however, postoperative complications remain a substantial concern. This review summarizes the incidence, risk factors, and management strategies for common complications after kidney transplantation. Reported incidence varies widely due to differences in definitions, diagnostic methods, and study designs. Ureteral stenosis occurs in 2.8-18.0% of recipients, vesicoureteral reflux in 0.5-86%, and urinary leakage in 1.1-7.2%. Lymphatic complications, including lymphocele and lymphorrhea, range from 0.6% to 35.2%, with one-third of complications requiring intervention. The incidence of urinary tract infections ranges from 20 to 43%, while asymptomatic bacteriuria is reported in up to 53% of recipients. Surgical site infections have a median incidence of 3.7%, and incisional hernias develop in 2.5-10% of cases, depending on follow-up duration. Vascular complications affect approximately 10% of recipients, with renal artery stenosis and thrombosis being the most prevalent. Neurologic complications, such as femoral nerve palsy and immunosuppression-related neurotoxicity, though less frequent, can impair recovery. Management strategies vary depending on severity, ranging from observation to surgical intervention. Preventive measures-including optimized ureteral stenting protocols, early catheter removal, careful immunosuppression, and appropriate antimicrobial use-play a crucial role in reducing complication risk. Despite advances in transplantation techniques and perioperative care, these complications continue to affect graft survival and patient outcomes. Further research is needed to standardize definitions and establish evidence-based protocols.

The Effectiveness of the Surgical Correction of Vesicoureteral Reflux on Febrile Urinary Tract Infections after a Kidney Transplant: A Single-Center Retrospective Study

Background/Objectives: Vesicoureteral reflux (VUR) is considered one of the major causes of post-renal transplant febrile urinary tract infections (UTI), leading to impaired renal function and the premature loss of the renal graft. We aimed to evaluate whether surgical VUR correction, such as open redo ureteric reimplantation, could be an option for treatment and provide better outcomes in post-transplant care for patients with UTI compared to their pre-VUR correction clinical state. Methods: Our study presents a retrospective analysis of 10 kidney transplant recipients with febrile UTI at the Renal Transplant Service of a Brazilian public hospital from 2010 to 2020. We selected patients who primarily underwent a surgical correction of post-transplant VUR, which was corrected by extravesical reimplantation without a stent in all patients by the same professional surgeon. Results: From 710 patients who received kidney transplants, 10 patients (1.4%) suffered from febrile UTI post-transplant and underwent surgical correction for VUR. Despite the study's limitations, such as its retrospective nature and limited sample size, the efficacy of open extravesical ureteral reimplantation in reducing post-operative febrile UTI in renal transplant patients was observed. Conclusions: As febrile UTI can contribute significantly to patient mortality after kidney transplantation and VUR emerges as a major cause of post-transplant febrile UTI, it is essential to treat it and consider the surgical outcome. This study emphasizes the timely detection and effective treatment of VUR via extravesical techniques to reduce febrile UTI occurrences post-transplant and it contributes insights into the role of surgical interventions in addressing VUR-related complications post-kidney transplantation.

Vesicoureteral reflux treatment following kidney transplantation potentially prevents graft function deterioration and allows long-term graft survival

OBJECTIVES

The impact of vesicoureteral reflux post-kidney transplantation on graft survival remains unclear, and guidelines on appropriate vesicoureteral reflux management post-kidney transplantation are lacking. For this reason, we conducted a retrospective study on the impact of vesicoureteral reflux and its treatment on graft survival.

METHODS

We evaluated 347 consecutive kidney transplantation recipients, who also underwent a ureteroneocystostomy, between 1996 and 2012.

RESULTS

Vesicoureteral reflux was diagnosed in 55 cases (15.9%), with a median post-kidney transplantation duration of 50 months (range 0-172 months). Among these, 22 were monitored, 17 underwent transurethral collagen injections, and 16 received a ureteroneocystostomy. The 10-year graft survival rate was significantly lower in recipients with vesicoureteral reflux (68.9%) than in those without vesicoureteral reflux (84.4%) (P = 0.0165). Moreover, among the vesicoureteral reflux recipients, the 10-year graft survival rate was significantly higher in those whose vesicoureteral reflux was cured (80.1%) than in those whose vesicoureteral reflux persisted (53.6%) (P = 0.0062). Multivariate analysis showed that vesicoureteral reflux was significantly associated with both overall and death-censored graft loss (odds ratio 3.737 and 3.685; P = 0.0015 and P = 0.0052, respectively). Lastly, the incidence of interstitial fibrosis and tubular atrophy was higher in recipients with vesicoureteral reflux than in those without vesicoureteral reflux (P = 0.0009).

CONCLUSIONS

Post-kidney transplantation vesicoureteral reflux has a negative impact on long-term graft survival, and that treatment prevents graft deterioration. From the perspective of maintaining long-term graft function in kidney recipients, vesicoureteral reflux may be one of the most important complications to be addressed.

Allograft Vesicoureteral Reflux after Kidney Transplantation

Allograft vesicoureteral reflux (VUR) is a leading urological complication of kidney transplantation. Despite the relatively high incidence, there is a lack of consensus regarding VUR risk factors, impact on renal function, and management. Dialysis vintage and atrophic bladder have been recognized as the most relevant recipient-related determinants of post-transplant VUR, whilst possible relationships with sex, age, and ureteral implantation technique remain debated. Clinical manifestations vary from an asymptomatic condition to persistent or recurrent urinary tract infections (UTIs). Voiding cystourethrography is widely accepted as the gold standard diagnostic modality, and the reflux is generally graded following the International Reflux Study Committee Scale. Long-term transplant outcomes of recipients with asymptomatic grade I-III VUR are yet to be clarified. On the contrary, available data suggest that symptomatic grade IV-V VUR may lead to progressive allograft dysfunction and premature transplant loss. Therapeutic options include watchful waiting, prolonged antibiotic suppression, sub-mucosal endoscopic injection of dextranomer/hyaluronic acid copolymer at the site of the ureteral anastomosis, and surgery. Indication for specific treatments depends on recipient's characteristics (age, frailty, compliance with antibiotics), renal function (serum creatinine concentration < 2.5 vs. ≥ 2.5 mg/dL), severity of UTIs, and VUR grading (grade I-III vs. IV-V). Current evidence supporting surgical referral over more conservative strategies is weak. Therefore, a tailored approach should be preferred. Properly designed studies, with adequate sample size and follow-up, are warranted to clarify those unresolved issues.

Minimal-invasive management of urological complications after kidney transplantation

Kidney transplantation represents the gold standard treatment option for patients with end-stage renal disease. Improvements in surgical technique and pharmacologic treatment have continuously prolonged allograft survival in recent years. However, urological complications are frequently observed, leading to both postoperative morbidity and putative deterioration of allograft function. While open redo surgery in these patients is often accompanied by elevated surgical risk, endoscopic management of urological complications is an alternative, minimal-invasive option. In the present article, we reviewed the literature on relevant urological postoperative complications after kidney transplantation and describe preventive approaches during the pre-transplantation assessment and their management using minimal-invasive approaches.

Endourological application of polydimetilsiloxane in patients with symptomatic vesicoureteral reflux in the kidney graft

OBJECTIVE

To identify the results of polydimethylsiloxane application in the endourological management of symptomatic vesicoureteral reflux to the kidney graft and to determine the factors associated with persistent symptoms and with vesicoureteral reflux.

MATERIAL AND METHODS

We included 23 patients diagnosed with symptomatic VUR in kidney graft, evaluated from January 2010 to August 2018 in the High Specialty Medical Unit # 14 in Veracruz. These patients received endourological application of polydimethylsiloxane. The descriptive analysis was carried out, and, if possible, the relative risk measures for clinical failure (CF) were determined with odds ratio (OR).

RESULTS

18 (78.3%) patients presented clinical success (CS). There was a significant difference in the mean age (CS 30.61±9.7, CF 46.0±11.46; U Mann Whitney, P=.037), and in the number of episodes of AGPN prior to the application of PDMS (CS 2.27±1.27, CF 3.6±0.89, U Mann Whitney, P=.019). The most frequently identified pathogen was E. Coli, with 45.4%. VUR resolution was observed in 47.8% of the cases. There was a decreased degree of VUR in 73.9% of cases. A lower degree of VUR was determined as a protective factor for CF (OR: 0.031, 95% CI: 0.002-0.437, with P=.008).

CONCLUSIONS

The endourological application of PDMS proved to be useful in the management of patients with symptomatic VUR in kidney graft, as it decreased the VUR degree and allowed CS in most cases.

A survey of Canadian renal transplant surgeons: Use of ureteric stents and technique of the ureteroneocystotomy

INTRODUCTION

The role of ureteric stenting in renal transplant has been well-demonstrated. The goal of this survey was to determine the utilization of ureteric stents by Canadian transplant surgeons, and how the ureteroneocystotomy and followup is performed.

METHODS

An online survey was sent to the 40 surgeon members of the Canadian Society of Transplantation. The primary outcome was the rate of ureteric stent use at the time of renal transplantation. The secondary outcomes were the ureteric stent dwell time, use and type of prophylactic antibiotics, and the use of routine post-transplant ultrasonography.

RESULTS

All respondents (25) used ureteric stent routinely and 92% remove the stent between four and six weeks postoperatively. Prophylactic antibiotics were used 64% of the time for ureteric stent removal. The majority of surgeons do not routinely perform a post-stent removal ultrasound. Fifty-six percent of respondents perform a refluxing anastomosis.

CONCLUSIONS

Ureteric stents are routinely used in renal transplant in Canada. Areas for improvement and topics of debate identified from this survey are the need for peri-stent removal antibiotics, the role of post-stent removal ultrasound, the duration of stent dwell time, and the need for a non-refluxing ureteroneocystotomy.

Clinicopathologic Impact of Early Medullary Ray Injury in Patients Following Kidney Transplantation

BACKGROUND

Previously, we explored the histopathologic characteristics of medullary ray injury (MRI) inducing interstitial fibrosis and tubular atrophy (IF/TA) to determine its etiologies, which include calcineurin inhibitor (CNI) toxicity and urologic complications. However, we did not examine the effects of these etiologies on long-term kidney allograft prognosis, because biopsy timing differed among cases.

AIM

We examined the influence of early MRI on kidney allograft prognosis using protocol biopsies taken within a 3-month time frame.

METHODS

We defined early MRI as tubular degeneration with interstitial edema or mild fibrosis localized to the medullary ray. We divided 53 protocol biopsies into 2 groups, with and without early MRI. Early MRI+ cases with isometric vacuolization were classified as CNI toxicity; those with Tamm-Horsfall protein in the interstitium and a thyroidlike appearance were classified as urinary tract system abnormalities; remaining cases were classified as "others." We compared changes in serum levels of creatinine (sCr) over 3 years and fibrosis extent at 1 year.

RESULTS

The sCr levels were significantly higher in the MRI+ group than the MRI- group at 3 years (P = .024). Examining the 3 MRI+ subgroups, only the MRI+ urinary tract system abnormalities group had significantly high sCr levels compared to the MRI- group (P = .019). The MRI+ group showed significant signs of IF/TA at 1 year.

CONCLUSIONS

Early MRI after kidney transplantation was significantly more likely to develop IF/TA at 1 year and had higher sCr levels at 3 years. In such cases, intervention might preserve graft function over the long term.

Vesicoureteral Reflux in Kidney Transplantation

BACKGROUND

Vesicoureteral reflux (VUR) is frequently found after transplantation, but its impact on graft function, urine tract infection, and graft loss remains uncertain. Therefore our objective was to evaluate the effects of VUR on the outcome of renal transplantation.

MATERIAL AND METHODS

We included 1008 adult renal transplant recipients of whom a 1-week posttransplant voiding cystourethrogram was available. Study end points included occurrence of bacteriuria, renal function, and graft survival.

RESULTS

In total, 106 (10.5%) of 1008 graft recipients had a diagnosis of VUR on voiding cystography. The incidence of bacteriuria was comparable in the reflux and nonreflux group (17% vs 17.4%, P = .91). There was no significant difference in renal function at 3 months and 1 year in patients with and without VUR. One- and 5-year graft survival in patients with VUR was 85.8% and 82.1% compared to 87.3% and 83.0% in patients without VUR ( P = .68 and P = .80).

CONCLUSION

Posttransplant VUR has no correlations with early bacteriuria, renal function, and graft survival.

Diagnosis and management of ureteral complications following renal transplantation

When compared with maintenance dialysis, renal transplantation affords patients with end-stage renal disease better long-term survival and a better quality of life. Approximately 9% of patients will develop a major urologic complication following kidney transplantation. Ureteral complications are most common and include obstruction (intrinsic and extrinsic), urine leak and vesicoureteral reflux. Ureterovesical anastomotic strictures result from technical error or ureteral ischemia. Balloon dilation or endoureterotomy may be considered for short, low-grade strictures, but open reconstruction is associated with higher success rates. Urine leak usually occurs in the early postoperative period. Nearly 60% of patients can be successfully managed with a pelvic drain and urinary decompression (nephrostomy tube, ureteral stent, and indwelling bladder catheter). Proximal, large-volume, or leaks that persist despite urinary diversion, require open repair. Vesicoureteral reflux is common following transplantation. Patients with recurrent pyelonephritis despite antimicrobial prophylaxis require surgical treatment. Deflux injection may be considered in recipients with low-grade disease. Grade IV and V reflux are best managed with open reconstruction.

The current role of endourologic management of renal transplantation complications

Introduction. Complications following renal transplantation include ureteral obstruction, urinary leak and fistula, urinary retention, urolithiasis, and vesicoureteral reflux. These complications have traditionally been managed with open surgical correction, but minimally invasive techniques are being utilized frequently. Materials and Methods. A literature review was performed on the use of endourologic techniques for the management of urologic transplant complications. Results. Ureterovesical anastomotic stricture is the most common long-term urologic complication following renal transplantation. Direct vision endoureterotomy is successful in up to 79% of cases. Urinary leak is the most frequent renal transplant complication early in the postoperative period. Up to 62% of patients have been successfully treated with maximal decompression (nephrostomy tube, ureteral stent, and Foley catheter). Excellent outcomes have been reported following transurethral resection of the prostate shortly after transplantation for patients with urinary retention. Vesicoureteral reflux after renal transplant is common. Deflux injection has been shown to resolve reflux in up to 90% of patients with low-grade disease in the absence of high pressure voiding. Donor-gifted and de novo transplant calculi may be managed with shock wave, ureteroscopic, or percutaneous lithotripsy. Conclusions. Recent advances in equipment and technique have allowed many transplant patients with complications to be effectively managed endoscopically.

Value of routine voiding cystourethrography after renal transplantation

The impact of vesicoureteral reflux (VUR) on renal allograft outcomes is debatable, with small cohort studies reporting controversial results. The objective of this retrospective study was to evaluate long-term clinical effects of early VUR in a large cohort of kidney transplant patients. Posttransplantation voiding cystourethrography was used to evaluate 646 consecutive kidney transplant recipients before discharge. The study endpoints included VUR grade, death-censored graft or patient survival, renal function, proteinuria and occurrence of urinary tract infections (UTIs). Of the 646 recipients, 263 (40.7%) were diagnosed with VUR. VUR grade II was most common (19.8%), followed by grades III (10.2%), I (7.9%) and IV (2.8%). VUR was less common in transplantations performed by experienced compared to inexperienced surgeons (36% vs. 48%; p = 0.004). VUR did not affect death-censored graft or patient survival and was not associated with proteinuria or occurrence of UTIs. Patients with VUR had a lower eGFR at 1 year after transplantation than did patients without VUR (60 vs. 52 mL/min/1.73 m(2) ; p = 0.02), although this difference was not observed at 3 and 5 years after transplantation. We conclude that early VUR, a common finding among renal transplant patients, may not have a meaningful impact on long-term transplant outcomes.

Endoscopic application of dextranomer/hyaluronic acid copolymer in the treatment of vesico-ureteric reflux after renal transplantation

OBJECTIVE

• To evaluate the success of endoscopic dextranomer/hyaluronic acid copolymer (DHAC) application in the treatment of patients with recurrent urinary tract infections (UTIs) and vesico-ureteric reflux (VUR) into the transplanted graft after renal transplantation.

PATIENTS AND METHODS

• Between January 2008 and April 2009, 19 patients with recurrent UTIs presented VUR proven by voiding cystourethrography. • To correct VUR of the transplanted ureter, DHAC was injected endoscopically using hydrodistention technique. • Pre- and postoperative serum creatinine levels, the number of pre- and postoperative UTIs, postoperative complications and reflux resolution rate were recorded. The mean follow-up was 6.5 months.

RESULTS

• The average number of UTIs was reduced significantly from 4.89 (range 2-14) to 1.31 (range 0-4) on pre- and postoperative follow-up, respectively, of 6 months (P < 0.001). The success rate increased from 57.9% after the first injection to 78.9% after the second injection. • The remaining four patients with residual VUR received long-term low dose antibiotic prophylaxis. In total, two (10.5%) patients developed increasing creatinine levels postoperatively as a result of distal ureteral obstruction, and temporary urinary drainage was necessary in both patients.

CONCLUSIONS

• DHAC appears to be an efficient and minimal invasive method for treating VUR after renal transplantation with respect to short-term success. • Further investigation with a larger group of patients and longer follow-up is needed to evaluate the prolonged effect, as well as any potential side effects.