When does vesicoureteral reflux in pediatric kidney transplant patients need treatment?

Role of vesicoureteral reflux on pediatric kidney allograft function

BACKGROUND

Vesicoureteral reflux (VUR) is a common urologic complication of pediatric kidney transplant, though there is little data on the effect of VUR on histologic graft changes or graft survival.

METHODS

All pediatric patients who received a kidney transplant from 2007 to 2020 were selected for retrospective chart review. All participants underwent a voiding cystourethrogram (VCUG) at a 6-month post-transplant. Patients were then categorized into two groups based on vesicoureteral reflux grade: no/low-grade VUR (grades 0-2) and high-grade VUR (grades 3-5). Outcomes collected included graft failure rates, graft function, urinary tract infections (UTIs), proteinuria, and Banff scores at 3- and 12-month post-transplant surveillance kidney biopsies.

RESULTS

There were 74 pediatric patients who received a kidney transplant in the designated time-period, and of those 39 had no/low-grade VUR and 35 had high-grade VUR. There was no difference in graft failure among the two groups over time when stratified for age (p = 0.389, CI 0.53-5.08). Patients with high grade VUR had a higher risk of UTI development overall (RR 1.89, 95%CI 1-3.6, p = 0.041), mostly accounted for from increased development of febrile UTI (RR 1.66, 95%CI 1.1-2.6, p = 0.038).

CONCLUSIONS

Unselected pediatric kidney transplant recipients with high-grade vesicoureteral reflux on VCUG at a 6-month post-kidney transplant are more likely to have febrile UTI compared to those in the low-grade VUR group. There is no difference in graft survival among the two groups.

The Extended Utilization of Bulking Agents in Pediatric Urology

PURPOSE OF REVIEW

Traditional surgical management for urinary incontinence and vesicoureteral reflux often requires complex reconstructive surgery and extended hospitalizations. Since the introduction of endoscopic bulking agents in 1973, there has been increasing interest in the use of endoscopic injection (EI) and bulking for the treatment of a variety of pediatric urologic disorders. The purpose of this review is to summarize the most recent literature addressing the use of bulking agents in pediatric urology.

RECENT FINDINGS

The most recent literature has focused primarily on the use of EI of bulking agents at the bladder neck for the treatment of urinary incontinence. Other uses of EI of bulking agents has focused on the treatment of vesicoureteral reflux (VUR) in patients with anatomic abnormalities or treatment of incontinence catheterizable channels. The development of advanced techniques for endoscopic injection along with safe, stable bulking agents has allowed for the treatment of a variety of urologic conditions. This minimally invasive procedure offers an additional tool for the pediatric urologist's armamentarium in the treatment of urinary incontinence and VUR.

Different profiles of acute graft pyelonephritis among kidney recipients from standard or elderly donors

Background

Acute graft pyelonephritis (AGPN) is a relatively common complication in kidney transplants (KTs); however, the effects on allograft function, diagnostic criteria, and risk factors are not well established.

Methods

Retrospective analysis of all consecutive adult KTs was performed between 01 January 2011 and 31 December 2018 (follow-up ended on 31 December 2019) to examine the association between the diagnosis of AGPN (confirmed with magnetic resonance imaging [MRI]) during the first post-transplantation year and graft outcomes.

Results

Among the 939 consecutive KTs (≈50% with donors ≥60 years), we identified 130 MRI-confirmed AGPN episodes, with a documented association with recurrent and multidrug-resistant bacterial urinary tract infections (UTIs) (p < 0.005). Ureteral stenosis was the only risk factor associated with AGPN (OR 2.9 [95% CI, 1.6 to 5.2]). KTs with AGPN had a decreased allograft function at the first year (ΔeGFR 6 mL/min/1.73 m2 [-2-15] in non-AGPN vs. -0.2 [-6.5-8.5] in AGPN, p < 0.001), with similar and negative profiles in KTs from standard or elderly donors. However, only KTs with AGPN and a donor <60 years showed reduced death-censored graft survival (p = 0.015); most of this subgroup received anti-thymocyte globulin (ATG) induction (40.4% vs. 17.7%), and their MRI presented either a multifocal AGPN pattern (73.9% vs. 56.7%) or abscedation (28.3% vs. 11.7%). No difference was noted in death-censored graft survival between early (<3 months post-KT) or late (3-12 months) AGPN, solitary/recurrent forms, or types of multidrug-resistant pathogens. Linear regression confirmed the independent role of multifocal pattern, abscedation, ATG induction, and donor age on the eGFR at the first year.

Conclusion

AGPN, influenced by multifocal presentation, ATG induction, donor age, and abscedation, affects kidney function and significantly impacts allograft survival in KTs with donors <60 years.

Current management of symptomatic vesicoureteral reflux in pediatric kidney transplantation-A European survey among surgical transplant professionals

BACKGROUND

Vesicoureteral reflux (VUR) is common in children and adolescents undergoing kidney transplantation (KTx) and may adversely affect allograft kidney function.

METHODS

To explore the current management of symptomatic native and allograft VUR in pediatric KTx recipients, an online survey was distributed to European surgical transplant professionals.

RESULTS

Surgeons from 40 pediatric KTx centers in 18 countries participated in this survey. Symptomatic native kidney VUR was treated before or during KTx by 68% of the centers (all/selected patients: 33%/67%; before/during KTx: 89%/11%), with a preference for endoscopic treatment (59%). At KTx, 90% favored an anti-reflux ureteral reimplantation procedure (extravesical/transvesical approach: 92%/8%; preferred extravesical technique: Lich-Gregoir [85%]). Management strategies for symptomatic allograft VUR included surgical repair (90%), continuous antibiotic prophylaxis (51%), bladder training (49%), or noninterventional surveillance (21%). Redo ureteral implantation and endoscopic intervention for allograft VUR were equally reported (51%/49%).

CONCLUSIONS

This survey shows uniformity in some surgical aspects of the pediatric KTx procedure. However, with regard to VUR, there is a significant variation in practice patterns that need to be addressed by future well-designed and prospective studies. In this way, more robust data could be translated into consensus guidelines for a more standardized and evidence-based management of this common condition in pediatric KTx.

Contrast-enhanced voiding urosonography (CEVUS) as a safe alternate means of assessing vesicoureteral reflux in pediatric kidney transplant patients

BACKGROUND

Although voiding cystourethrogram (VCUG) is currently the gold standard in VUR evaluation, there is ionizing radiation exposure. Contrast-enhanced voiding urosonography (CEVUS) uses ultrasound contrast agents to visualize the urinary tract and has been reported to be safe and effective in VUR evaluation in children. CEVUS application has yet to be specifically described in VUR evaluation in the pediatric kidney transplant population. The purpose of this study was to report the use of CEVUS and VCUG in evaluating and managing VUR in pediatric renal transplant patients.

METHODS

Retrospective review was conducted for pediatric kidney transplant patients (18 years and younger) who underwent VCUG or CEVUS to assess for transplant VUR from July 2019 through June 2021. Demographic information, reason for VUR evaluation, fluoroscopy time, and postimaging complications were evaluated. Costs of imaging modalities were also considered.

RESULTS

Eight patients were evaluated for transplant VUR during the study period. Of the 3 patients who underwent VCUG, all 3 had VUR (median grade 3). Median fluoroscopy time was 18 s and dose-area product was 18.7 uGy*m² . Of the 5 patients who underwent CEVUS, 4 had VUR (median grade 4). There were no complications for either modality. Based on clinical and radiographic findings, patients were recommended no intervention, behavioral modification, or ureteral reimplantation. The total cost of CEVUS was $800 less than that of VCUG.

CONCLUSION

CEVUS can provide an alternate means of safely evaluating VUR in kidney transplant patients with similar outcomes, potentially lower costs, and no exposure to ionizing radiation.

Urologic Considerations in Pediatric Chronic Kidney Disease

Common causes of pediatric ESRD are distinct from those seen in the adult population. In the pediatric population, the most common are congenital anomalies of the kidney and urinary tract (CAKUT), affecting approximately 30% of children with CKD. These structural anomalies often require coordinated care with the pediatric urology team to address voiding issues, bladder involvement, and the potential need for surgical intervention. For pediatric nephrologists and urologists, common CAKUT that are encountered include antenatal hydronephrosis, obstructive uropathies (eg, posterior urethral valves), and vesicoureteral reflux. As more pediatric patients with CAKUT, CKD, and ESRD transition to adult care, it is important for receiving adult nephrologists to understand the clinical presentation, natural history, and prognosis for these diagnoses. This review outlines the diagnosis and potential interventions for these conditions, including strategies to address bladder dysfunction that is often seen in children with CAKUT. A discussion of these management decisions (including surgical intervention) for CAKUT, which are quite common to pediatric nephrology and urology practices, may provide unique learning opportunities for adult nephrologists who lack familiarity with these pediatric conditions.

A systematic review of outcomes of Deflux® treatment for vesicoureteral reflux following pediatric renal transplantation

INTRODUCTION

Vesicoureteral reflux (VUR) after renal transplant in the pediatric population may be associated with an increased incidence of urinary tract infection (UTIs) leading to increased morbidity, including graft dysfunction and graft loss. The non-orthotopic location of the transplanted ureter, and lack of submucosal tunnel may pose challenges in correcting the VUR using endoscopic injection techniques. Herein we report the results of a systematic review evaluating the outcomes of endoscopic treatment of VUR using Deflux® in this population.

METHODS

Pubmed and Embase databases were searched from October 2001 to April 2019. Full-text English articles involving patients less than 18 years old at the time of transplant, with a diagnosis of VUR post-transplantation, who underwent Deflux® treatment were included. Figure 1 outlines our PRISMA-compliant search strategy.

RESULTS

We found 6 eligible studies describing Deflux® treatment outcomes in 67 pediatric patients with post-transplant VUR where voiding cystourethrogram (VCUG) confirmed the diagnosis and resolution of VUR. The mean success rate was 36.8%. Ureteral obstruction occurred in 7/67 cases (10.4%). In all these 7 cases of obstruction, ureteric stenting was the initial management, but was only successful in 1 patient. Open ureteroneocystostomy (UNC) was performed in 4/7 cases, while 2/7 were managed expectantly (unknown outcomes). Persistent VUR with UTI despite Deflux® were reported in 20 out of 67 cases. Of these, 7 were managed with prophylactic antibiotics, and 13 with UNC. Success rates were consistently low for UNC after failed Deflux® in comparison to redo UNC in transplant ureters without prior injection.

CONCLUSION

Low success rates are seen following injection techniques for VUR after pediatric renal transplant. Although an appealing option, Deflux® may prove counterintuitive due to the high rate of obstruction and suboptimal results if open reimplantation is required. A multi-institutional prospective study with a larger population size may further elucidate these results.

Treatment of Vesicoureteral Reflux Detected After Renal Transplant in Pediatric Patients: A Single-Center Experience

OBJECTIVE

In children who undergo renal transplant, vesicoureteral reflux on the transplanted kidney is a serious complication that may result in organ loss. In this study, we aimed to evaluate the results of endoscopic and open surgical techniques in the treatment of patients with recurrent urinary tract infections and vesicoureteral reflux after renal transplant.

MATERIAL AND METHODS

The files of pediatric patients who underwent renal transplant in our hospital between January 2016 and January 2019 were evaluated retrospectively. In this single-center analysis, we investigated the incidence of vesicoureteral reflux in the kidney transplant recipients and the results of various approaches to treat it.

RESULTS

Eighty pediatric patients underwent renal transplant between January 2016 and January 2019. Fourteen of those patients (17.5%, 7 female and 7 male) were diagnosed with vesicoureteral reflux in the postoperative period. Twelve of 14 patients received endoscopic injections as the first treatment. Clinical or radiological success was achieved in 5 patients (5 of 15 injection treatments, 33%); in 4 patients (4/12, 33.3%) success was after the first endoscopic injection treatment, and in 1 patient (1/3, 33.3%) success was after the second injection. Meanwhile, clinical or radiological success was achieved in 6 of 7 patients who underwent redo ureteroneocystostomy (6/7, 85.7%).

CONCLUSION

Although symptomatic vesicoureteral reflux after renal transplant is rare in pediatric patients, it is an important cause of morbidity as it requires recurrent surgical procedures. Although endoscopic treatment is safe and minimally invasive, the success rate is lower than expected, and redo of ureteral reimplant may be required in most cases.

Renal Transplant Hydroureteronephrosis as a Manifestation of Rejection: An Under-Recognized Entity?

Hydroureteronephrosis (HUN) of the renal transplant (RT) can be obstructive or non-obstructive, refluxing or non-refluxing, and can cause allograft dysfunction. HUN of the RT as a manifestation of rejection is uncommon and has not been described in children. We describe two pediatric RT recipients who presented with late-onset HUN, 5 and 10 years after transplantation. Both had new-onset HUN which occurred at the time of rejection; HUN resolved in both patients after treatment of rejection. Renal function stabilized in both patients without the need for stent or nephrostomy tube placement. There was no obstruction or vesicoureteral reflux (VUR). Edema of the uroepithelial cells leading to transient obstruction causing HUN is a most likely explanation. We conclude that treatment of rejection in patients without obstruction or VUR may lead to resolution of HUN without the need for urological interventions.

Management of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years?

Vesicoureteral reflux (VUR) is associated with increased risks of urinary tract infection, renal scarring and reflux nephropathy. We review advancements over the last two decades in our understanding and management of VUR. Over time, the condition may resolve spontaneously but it can persist for many years and bladder/bowel dysfunction is often involved. Some factors that increase the likelihood of persistence (e.g., high grade) also increase the risk of renal scarring. Voiding cystourethrography (VCUG) is generally considered the definitive method for diagnosing VUR, and helpful in determining the need for treatment. However, this procedure causes distress and radiation exposure. Therefore, strategies to reduce clinicians' reliance upon VCUG (e.g., after a VUR treatment procedure) have been developed. There are several options for managing patients with VUR. Observation is suitable only for patients at low risk of renal injury. Antibiotic prophylaxis can reduce the incidence of UTIs, but drawbacks such as antibiotic resistance and incomplete adherence mean that this option is not viable for long-term use. Long-term studies of endoscopic injection have helped us understand factors influencing use and the effectiveness of this procedure. Ureteral reimplantation is still performed commonly, and robot-assisted laparoscopic methods are gaining popularity. Over the last 20 years, there has been a shift toward more conservative management of VUR with an individualized, risk-based approach. For continued treatment improvement, better identification of children at risk of renal scarring, robust evidence regarding the available interventions, and an improved VUR grading system are needed.

Increasing bladder capacity and vesicoureteral reflux in pediatric kidney transplant patients

OBJECTIVES

To investigate the frequency of vesicoureteral reflux, and the relationship of pretransplant decreased bladder capacity and post-transplant vesicoureteral reflux in children undergoing kidney transplantation.

METHODS

A voiding cystourethrography was carried out in 172 pediatric kidney transplantation recipients before, and 4 months after, transplantation to evaluate bladder capacity and vesicoureteral reflux. The correlation of post-transplant vesicoureteral reflux with pretransplant bladder capacity, vesicoureteral reflux in the native kidney and the method of ureteral reimplantation (intravesical/extravesical) was analyzed. Atrophic bladder was defined as having ≤50% functional bladder capacity (age in years + 2) × 25 (mL) or ≤150 mL in patients aged >10 years.

RESULTS

Bladder capacity increased remarkably after transplantation in both post-transplant vesicoureteral reflux- group (from 180 to 253 mL) and vesicoureteral reflux+ group (from 82 to 171 mL). Voiding cystourethrography showed vesicoureteral reflux in 12 cases of kidney transplantation (7%; grade 1: 2, grade 2: 3, grade 3: 7). Pretransplant atrophic bladder was an independent risk factor of post-transplant vesicoureteral reflux (P = 0.004, hazard ratio 9.5). There was no difference in renal function between the vesicoureteral reflux- group and vesicoureteral reflux+ group at 4 months to 5 years post-transplantation.

CONCLUSIONS

Pretransplant atrophic bladder is a risk factor of post-transplant vesicoureteral reflux in pediatric patients. However, bladder capacity can remarkably increase after transplantation, and kidney function in the post-transplant vesicoureteral reflux+ group is stable.