Increased urologic complications in children after kidney transplants for obstructive and reflux uropathy

Posterior urethral valves and kidney transplantation: Identifying opportunities for improvement

BACKGROUND

Posterior urethral valves (PUV) represents a heterogenous spectrum in which guidelines for management are lacking particularly for those patients facing end-stage kidney disease and transplant. In this study we aim to 1) evaluate our long term PUV pediatric transplant outcomes compared to those without lower urinary tract dysfunction and 2) assess our PUV cohort for trends in bladder management and evaluate outcomes to inform development of institutional guidelines.

MATERIALS AND METHODS

A retrospective cohort analysis of all patients with a diagnosis of PUV who underwent kidney transplant from 2000 to 2023 was completed. A matched cohort of patients without lower urinary tract dysfunction was identified for comparison of graft function. Charts of PUV patients were reviewed for both sociodemographic and clinical variables. Patients were classified by bladder management at the time of transplantation into three separate groups for analysis: voiding, clean intermittent catheterization, and incontinent diversion. Primary outcomes of interest were eGFR, graft failure, and UTIs post-transplant.

RESULTS

45 patients met inclusion criteria. 69% were on dialysis prior to transplant. 51% of grafts were from a deceased donor. Bladder management consisted of voiding (62%), CIC (4 via urethra, 10 via channel) (31%), and incontinent diversion (7%). 20% underwent augmentation cystoplasty (5 = ureter, 2 = gastric, 1 = colon, and 1 = ileum) prior to or at the time of transplant. Median follow up duration was 5.4 years (3.0, 10.8). Patients on CIC had higher rates of UTI; however, we found no significant difference in graft function outcomes (eGFR, graft failure) between bladder management groups or year of transplant. VUR in the transplant kidney was associated with vesicostomy (p = 0.028). 2 of 2 gastric augments developed malignancy, one of which was cause of death. Graft failure rate was 22% in both the PUV group and matched cohort, with median interval times to failure of 6.7 years and 3.7 years, respectively (p = 0.71). There were no differences in eGFR at follow-up time points between the PUV and matched cohort.

CONCLUSIONS

Patients with PUV represent a spectrum of disease with heterogeneous management before and after kidney transplant. Overall, graft function outcomes were similar when compared to matched cohort without lower urinary tract dysfunction. Patients on CIC had higher rates of UTI but without impact on graft function. Gastric augmentation cystoplasty should be avoided given risk for malignancy. Guidelines to standardize evaluation and management would be helpful for patient care and outcomes.

Ureteral stricture after pediatric kidney transplantation: Is there a role for percutaneous antegrade ureteroplasty?

INTRODUCTION

Ureteral obstruction following pediatric kidney transplantation occurs in 5-8% of cases. We describe our experience with percutaneous antegrade ureteroplasty for the treatment of ureteral stricture in pediatric kidney transplant patients.

METHODS

We retrospectively reviewed all pediatric kidney transplantation patients who presented with ureteral stricture and underwent percutaneous antegrade ureteroplasty at our institution from July 2009 to July 2021. Variables included patient demographics, timing of presentation, location and extent of stricture, ureteroplasty technique and clinical outcomes. Our primary outcome was persistent obstruction of the kidney transplant.

RESULTS

Twelve patients met inclusion criteria (4.2% of all transplants). Median age at time of ureteroplasty was 11.5 years (range: 3-17.5 years). Median time from kidney transplantation to ureteroplasty was 3 months. Patency was maintained in 50% of patients. Seven patients (58.3%) required additional surgery. Four patients developed vesicoureteral reflux. Patients with persistent obstruction had a longer time from transplant to ureteroplasty compared to those who achieved patency (19.3 vs 1.3 months, p = 0.0163). Of those treated within 6 months after transplantation, two patients (25%) required surgery for persistent obstruction (p = 0.06). All patients treated >1 year after transplantation had persistent obstruction following ureteroplasty (p = 0.06).

CONCLUSION

Percutaneous antegrade ureteroplasty can be considered a viable minimally invasive treatment option for pediatric patients who develop early ureteral obstruction (<6 months) following kidney transplantation. In patients who are successfully treated with ureteroplasty, 67% can develop vesicoureteral reflux into the transplant kidney. Patients who fail early percutaneous ureteroplasty or develop obstruction >1 year after transplantation are best managed with surgical intervention.

Outcomes of kidney transplants in pediatric patients with the vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, limb abnormalities association

In this single-center retrospective study, we analyzed kidney transplant outcomes in nine pediatric patients with VACTERL [vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, limb abnormalities] association-making this the largest study of its kind. Of 743 pediatric kidney transplant recipients at our center (1980-2017), nine had documented diagnoses of VACTERL association. All nine had congenital anorectal malformations and renal anomalies, five had vertebral defects, and one had a bifid thumb and tracheoesophageal fistula. Renal anomalies included dysplasia (n = 6), aplasia (n = 3), and horseshoe kidney (n = 2). Congenital lower urinary tract anomalies included neurogenic bladder (n = 6), obstructive uropathy (n = 4), anovesicular fistula (n = 1), rectourethral fistula (n = 1), and posterior urethral valves (n = 1). Age at transplant ranged from 1.2 to 15 years (mean, 7.3; standard deviation [SD], 5.5); 6 (67%) were male, and 3 (33%) were female; 6 (67%) had a living related donor, and 3 (33%) had a deceased donor. The overall graft survival rate was 78% (range, 1.5 to 25.2 years; mean, 10.5; SD, 8.9). One month post-transplant, one recipient died with a functioning graft. At 3.7 years post-transplant, one graft failed because of recurrent pyelonephritis. Post-transplant urologic complications included pyelonephritis (n = 6), vesicoureteral reflux (n = 5), and graft hydronephrosis (n = 4). We conclude that pediatric patients with VACTERL association can be safely transplanted-careful patient selection with vigilance and intervention for pre- and post-transplant urologic complications is essential.

Comparing treatment modalities for transplant kidney vesicoureteral reflux in the pediatric population

INTRODUCTION

Non-refluxing ureteral reimplantation is favored in pediatric renal transplantation to prevent complications, such as vesicoureteral reflux (VUR) in the transplant ureter. VUR resulting in febrile urinary tract infections remains a problem in this population, leading to repeated hospitalizations and increased morbidity. Revision of the vesicoureteral anastomosis can be a surgical challenge due to scar tissue and tenuous vascularity of the transplant ureter. Therefore, alternative options such as endoscopic injection of Deflux at the neo-orifice and surveillance with prophylactic antibiotics have emerged as potential treatment modalities for transplant ureter VUR.

OBJECTIVE

The authors reviewed their experience of the management of VUR in the transplant ureter, comparing outcomes of various modalities.

STUDY DESIGN

With Institutional Review Board approval, a retrospective chart review of all renal transplant patients from January 2002 to January 2017 was conducted. All patients with VUR on voiding cystourethrogram (VCUG) after surgery were identified. Indications for end-stage renal disease, urologic comorbidities, pretransplant VCUG, and operative details were recorded. After transplantation, febrile urinary tract infections, ultrasound findings, and any further interventions-surveillance, subureteral endoscopic injection of Deflux, or ureteral reimplantation-were documented along with their outcomes.

RESULTS

Overall, VUR was identified in 35/285 (12.3%) transplant patients after a non-refluxing ureteroneocystostomy. VUR was managed with surveillance in 17/35 (49%), intravesical Deflux injection in 11/35 (31%), and immediate redo ureteral reimplantation in 7/35 (20%). Ten out of 11 patients undergoing Deflux injection had a postoperative VCUG. All patients developed VUR recurrence; the majority showed immediate failure and only 1/10 showed late recurrence. Of the immediate failures, 3/9 patients were maintained on prophylactic antibiotics, and 6/9 patients underwent ureteral reimplantation. In these six patients undergoing reimplantation after failed Deflux, 3/6 (50%) patients required additional surgeries: One patient developed recurrence of reflux and two patients developed ureterovesical junction obstruction. In contrast, no complications were seen in patients undergoing primary ureteral reimplantation.

DISCUSSION

The study is limited by low numbers and a retrospective design. However, the results of this study differ significantly from the published Deflux series showing a success rate of more than 50% in the treatment of transplant kidney VUR. In fact, post-Deflux redo ureteral reimplantation was associated with an increased risk of postoperative complication.

CONCLUSION

The use of Deflux in the post-transplant setting has poor results. In the study series, 11/11 patients demonstrated clinical and radiographic failure. Therefore, as an institution the authors do not recommend Deflux as first-line treatment of VUR in the transplant patient.

Urologic Evaluation and Management of Pediatric Kidney Transplant Patients

Urologic causes of end-stage renal disease are estimated between 25% and 40% of causes. The goal of renal transplantation in chronic kidney disease patients is to provide renal replacement therapy with less morbidity, better quality of life, and improved overall survival compared with dialysis. A patient's urologic history can be a significant source of problems related to infections, recurrence of disease, and surgical complications. Many of the urologic risks are modifiable. Proper evaluation and management can mitigate the potential problems after transplantation, and these patients with complex urologic problems are seen to have similar graft function outcomes.

Risk factors for urological complications following living donor renal transplantation in children

The aim of this study was to detect possible risk factors for UC and UTI following pediatric renal Tx and effect of these complications on outcome. One hundred and eight children who underwent living donor Tx between 2009 and 2015 were retrospectively included. Extraperitoneal approach was used with stented tunneled extravesical procedure. Mean recipient age was 9.89 ± 3.46 years while mean weight was 25.22 ± 10.43 kg. Seventy-three (67.6%) recipients were boys while 92 (85.2%) were related to donors. Urological causes of ESRD were present in 33 (30.6%) recipients (14 [13%] posterior urethral valve, 16 [14.8%] VUR, and 3 [2.8%] neurogenic bladder). Augmentation ileocystoplasty was performed in 9 (8.3%) patients. Mean follow-up was 39.3 ± 17.33 months. UC were detected in 10 (9.3%) children (leakage 4 [3.7%], obstruction 3 [2.8%], and VUR 3 [2.8%]) while UTIs were reported in 40 (37%) children. After logistic regression analysis, UC were significantly higher in children with cystoplasty (44.4% vs 6.1%; P = .001). UTIs were significantly higher in girls (51.4% vs 30.1%; P = .001) and in children with urological causes of ESRD (51.5% vs 30.7%; P = .049). UC and UTI were not significantly associated with increased graft loss or mortality. UC were significantly higher in children with cystoplasty while UTIs were significantly higher in girls and children with urological causes of ESRD. Presence of UC did not affect the rate of graft loss or mortality due to its early detection and proper management.

Long-term Outcome of 1-step Kidney Transplantation and Bladder Augmentation Procedure in Pediatric Patients

BACKGROUND

Guidelines for bladder augmentation (BA) in kidney transplantation (KT) recipients are not well-defined. In our center, simultaneous BA with KT (BA-KT) is performed. We assessed transplantation outcomes of this unique extensive procedure.

METHODS

A case-control single center retrospective study. Transplantation outcomes were compared with those of KT recipients who did not need BA.

RESULTS

Compared with 22 patients who underwent KT only, for 9 who underwent BA-KT, surgical complications and the need for revision in the early posttransplantation period were similar; early graft function was better: estimated glomerular filtration rate, 96.5 ± 17.1 versus 79.4 ± 16.6 mL/min at 0 to 6 months (P = 0.02); posttransplantation clean intermittent catheterization was more often needed: by 78% (7/9) versus 13% (3/22); and asymptomatic bacteriuria was more common: 100% versus 9% during the first 6 months (P < 0.001), 55% versus 9% (P = 0.02) and 66.6% versus 9% during the first and second years, respectively (P = 0.004). Urinary tract infection (UTI) incidence was also higher: 100% versus 23% during the first 6 months and 44% versus 9% during the second year posttransplantation. Graft function deteriorated significantly in the BA-KT group by the fifth posttransplantation year: estimated glomerular filtration rate was 47.7 ± 39.7 mL/min versus 69 ± 21.3 mL/min, with only 6 (66%) of 9 functioning grafts versus 100% in the KT only group. Causes of graft loss were noncompliance with drug therapy in 2 patients and recurrent UTIs in 2 patients.

CONCLUSIONS

Excellent short-term outcome for simultaneous BA-KT is threatened by graft loss due to a high prevalence of UTIs and patient noncompliance with the demanding complex posttransplantation therapy.

Favorable Outcomes of Renal Transplant in Children With Abnormal Lower Urinary Tract

OBJECTIVES

Chronic kidney disease caused by lower urinary tract abnormalities is a significant complication in pediatric care. Although there are conflicting reports about clinical outcomes in the past, favorable outcomes have been reported in recent years. Despite this, many centers still refrain from performing renal transplant in these patients. Here, we compared clinical outcomes of renal transplant recipients with and without lower urinary tract abnormalities.

MATERIALS AND METHODS

Our study included 71 renal transplant recipients who were divided into 3 groups: 17 patients with abnormal lower urinary tracts having vesicoureteral reflux (group 1), 7 patients with abnormal lower urinary tracts having bladder dysfunction (group 2), and 47 patients with anatomically and functionally normal lower urinary tracts (group 3). We retrospectively compared demographic features, clinical course, graft survival, pre- and posttransplant incidence of urinary tract infections, and final graft function among the groups.

RESULTS

There were no statistically significant differences among groups regarding median age at time of transplant, graft survival, median creatinine level, and median glomerular filtration rate (P > .05). Significant differences were shown in incidence of urinary tract infections between patients in groups 1 and 2 (abnormal lower urinary tracts) and group 3 (normal lower urinary tracts) before transplant (P < .05). Although frequency of urinary tract infections in groups 1 and 2 were moderately higher than shown in group 3 after transplant, this difference was not statistically significant.

CONCLUSIONS

Although the children with abnormal lower urinary tracts had slightly higher incidence of urinary tract infections, there were no differences between patients with abnormal and normal lower urinary tracts regarding allograft survival and function. In addition, proper follow-up of patients before and after transplant, based on our experience, should include educating patients and their parents about potential complications after transplant for the best outcome of renal transplant.

Renal transplantation in infants

Renal transplantation (RTx) has become an accepted mode of therapy in infants with severe renal failure. The major indications are structural abnormalities of the urinary tract, congenital nephrotic syndrome, polycystic diseases, and neonatal kidney injury. Assessment of these infants needs expertise and time as well as active treatment before RTx to ensure optimal growth and development, and to avoid complications that could lead to permanent neurological defects. RTx can be performed already in infants weighing around 5 kg, but most operations occur in infants with a weight of 10 kg or more. Perioperative management focuses on adequate perfusion of the allograft and avoidance of thrombotic and other surgical complications. Important long-term issues include rejections, infections, graft function, growth, bone health, metabolic problems, neurocognitive development, adherence to medication, pubertal maturation, and quality of life. The overall outcome of infant RTx has dramatically improved, with long-term patient and graft survivals of over 90 and 80 %, respectively.

Should a complex uropathy be a contraindication for renal transplantation in children?

BACKGROUND

Anatomic and functional disorders of the lower urinary tract represent up to 40% of the causes of renal failure in children. Several centers avoid renal transplantation in these patients because of the high risk of complications and lower graft survival. The aim of this work was to determine the frequency of urinary tract abnormalities (UTAs) among our pediatric series, and to compare the frequency of complications, function, and long-term graft survival among patients without versus with UTA.

METHODS

This single-center, retrospective study compared outcomes between pediatric recipients with versus without UTA. We analyzed demographic features, etiology, pretransplant protocol, urinary tract rehabilitation, incidence of complications, rejection events, as well as graft function and survival.

RESULTS

Among 328 pediatric cases performed between 1998 and 2008, we excluded nine patients due to incomplete medical records, analyzing 319 procedures in 312 patients. Sixty-seven patients (21%) had UTA. The average age, weight, and height at the time of grafting were significantly lower in the urologic group: 11.1 versus 12.6 years, 28.8 versus 34.4 kg; 125.4 versus 138.4 cm, respectively. There were significantly higher frequencies of a transperitoneal approach and vena cavae and aortic anastomoses among patients with UTA (P < .001), posing a greater technical challenge in this population. No differences in creatinine levels were observed at 0.5, 1, 2, 5, and 10 years: 1.3 versus 1.6 at 5 years, and 1.4 versus 1.5 at 8 years. Urologic complications, including urinary tract infections (UTIs), occurred among 80.6% of patients with UTA versus 42.1% in the non-UTA group (P < .001). UTIs appeared predominantly in patients with UTA (62.7% vs 35.3%, P < .001), representing a 2.7-fold risk compared with those children transplanted for other reasons. Rejection incidence was similar in both groups (49.8%). There was no significant difference in 5-y (89.8% vs 85%) or 10-year (83% vs 67%) graft survivals between the groups (P = .162).

CONCLUSION

Our results demonstrated that with proper interdisciplinary care, graft and patient survivals of pediatric recipients with UTAs were not affected; therefore, these patients should not be rejected for transplantation.

Urinary tract infections in pediatric renal transplant recipients--a two center risk factors study

UTI are common in renal Tx recipients and may significantly impact on the graft function. The aim of our study was to evaluate the prevalence, risk factors, and significance of UTI in Tx children. We performed a retrospective cross-sectional study of 76 Tx patients, median age at Tx was 13.4 yr. Twenty-one of 76 (28%) patients developed at least one UTI during the mean follow-up time of 3.3 +/- 2.0 yr post-Tx. The first UTI occurred at a median of 160 days post-Tx. The RR of having UTI was significantly higher in patients with the primary diagnosis of obstructive uropathy (RR = 2.6, 95th CI = 1.1-6.0, p = 0.032), history of PN pre Tx (RR = 2.7, 95th CI = 1.3-5.4, p = 0.009) and pre Tx VUR (RR = 2.2, 95th CI = 1.1-4.5, p = 0.045). These three factors also significantly decreased the infection-free survival time to the first UTI. Most UTI caused reversible acute allograft dysfunction, but the long-term graft function could not be reliably assessed with SCr. In conclusion, UTI occurred in 28% of pediatric Tx recipients, mostly during the first year post-Tx despite antibiotic prophylaxis. The diagnosis of obstructive uropathy, history of UTI and VUR prior to Tx were significant risk factors.

Chronic kidney disease in the VACTERL association: clinical course and outcome

Approximately 60% of VACTERL (vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula with atresia, renal defects/radial limb dysplasia) patients have renal anomalies that can be associated with chronic kidney disease (CKD). With improved medical care, a large proportion of these patients survive into adulthood. Longitudinal follow-up data regarding the management of kidney disease in these children is lacking. Twelve VACTERL patients with CKD stage 2-5 and 12 age-matched controls with similar urologic anomalies and CKD [mean follow-up period 15.0 +/- 1.4 (SE) and 11.9 +/- 2.1 years, respectively] were identified in a single center. Eight VACTERL patients progressed to end-stage renal disease (ESRD) compared to four controls (66.7 vs. 33.3%, respectively). Six VACTERL patients were dialyzed pre-transplant. Of the four patients on peritoneal dialysis (PD), three had to be switched to hemodialysis due to complications, whereas two of the three controls on PD did not experience significant problems. Seven VACTERL patients underwent renal transplantation compared to four controls. Mean creatinine clearance 2 years post-transplant was 65.8 +/- 6.3 in VACTERL patients vs. 87.8 +/- 7.1 ml/min per 1.73 m(2) in controls (p = 0.03). VACTERL patients had a significantly lower mean height standard deviation score than the controls (-2.34 +/- 0.41 vs. -1.27 +/- 0.24, respectively; p < 0.05). Based on these results, VACTERL patients with CKD develop ESRD more frequently, experience more complications with dialysis, may have a poorer transplant outcome, and have more severe growth failure than controls.

Urological issues in pediatric renal transplantation

PURPOSE OF REVIEW

The pediatric patient with end-stage renal disease provides a great opportunity for the involvement of the pediatric urologist because of the high incidence of associated urologic anomalies.

RECENT FINDINGS

Renal transplant remains the procedure of choice in the child with end-stage renal disease. The durability of survival of the graft is impacted by successful management of the genitourinary tract.

SUMMARY

Preoperative, intraoperative, and postoperative evaluation is critical for the child with associated urologic disease and end-stage renal disease. Early and appropriate management may stabilize renal function and prolong the time to transplant. Due to the relatively long life expectancy of children compared with adults with end-stage renal disease, appropriate management may be of benefit to avoid the morbidity associated with renal replacement therapy. In certain children, the appropriate management and reconstruction of the genitourinary tract may allow for a planned and preemptive renal transplant, thus avoiding dialysis.