RENAL TRANSPLANTATION IN CHILDREN WITH POSTERIOR URETHRAL VALVES REVISITED: A 10-YEAR FOLLOWUP

Outcomes of kidney transplantation in patients with congenital anomalies of the kidney and urinary tract: a propensity-score-matched analysis with case-control design

BACKGROUND

We compared long-term outcomes after kidney transplantation (KTx) in patients with and without congenital anomalies of the kidney and urinary tract (CAKUT).

METHODS

KTx recipients (KTRs) with CAKUT in 1980-2016 were identified; their hard copy and electronic medical records were reviewed and compared to a propensity-score-matched control group (non-CAKUT) from the same period. The primary outcomes were graft loss or death with a functioning graft; secondary outcomes included posttransplant urinary tract infections (UTIs) and biopsy-proven rejection (BPR).

RESULTS

: We identified 169 KTRs with CAKUT and 169 matched controls. Median follow-up was 132 (IQR: 75.0-170.0) months. UTIs were more common in CAKUT patients compared to non-CAKUT group (20.7% vs 10.7%; p = 0.01). Rates of BPR were similar between the two groups. In Kaplan-Meier analysis, 10-year graft survival rates were significantly higher in the CAKUT group than in the non-CAKUT group (87.6% vs 69.2%; p < 0.001), while patient survival rates were similar. In multivariate Cox regression analyses, CAKUT (HR: 0.469; 95% CI: 0.320-0.687; p < 0.001) and PRA positivity before transplantation (HR: 3.756; 95% CI: 1.507-9.364; p = 0.005) predicted graft loss.

DISCUSSION

Graft survival in KTRs with CAKUT appears superior to KTRs without CAKUT. Transplant centers should develop multidisciplinary educational and social working groups to support and encourage CAKUT patients with kidney failure to seek for transplants.

Long-Term Renal Transplant Outcome in Patients With Posterior Urethral Valves. Prognostic Factors Related to Bladder Dysfunction Management

Introduction: To obtain a successful renal transplant (RT) outcome in patients with posterior urethral valves (PUV), it is necessary to accomplish an adequate bladder dysfunction treatment. Our aim was to determine prognostic factors related to bladder dysfunction management in long-term RT outcome in patients with PUV. Methods: A retrospective review of patients with PUV who received a first RT after 1985 in our institution with at least 5 years of follow-up was performed. Variables analyzed included prenatal diagnosis, age of diagnosis, initial presentation and management, bladder dysfunction treatment, other surgical treatments, pre-transplant dialysis, age of transplantation, type of donor, immunosuppression regimen, vascular and urological complications, rejections episodes, and graft survival. Results: Fifty-one patients were included in the analysis. Prenatal diagnosis was done in 37.3%. Median age of diagnosis was 0.30 (0-88) months. Initial presentation was vesicoureteral reflux (VUR) in 78% and obstructive ureterohydronefrosis in 35.3%. Initial management was valve ablation (29.4%), pyelo-ureterostomy (64.7%), and vesicostomy (5.9%). In 33.3%, a type of bladder dysfunction treatment was performed: 21.6% bladder augmentation (BA), 15.7% Mitrofanoff procedure, 17.6% anticholinergic drugs, and 27.5% clean intermittent catheterization (CIC). Pre-transplant dialysis was received by 66.7%. Transplantation was performed at 6.28 ± 5.12 years, 62.7% were cadaveric and 37.3% living-donor grafts. Acute rejection episodes were found in 23.6%. Urological complications included recurrent urinary tract infections (UTIs) (31.4%); native kidneys VUR (31.4%); graft VUR (45.1%); and ureteral obstruction (2%). Vascular complications occurred in 3.9%. Mean graft survival was 11.1 ± 6.9 years. Analyzing the prognostic factor that influenced graft survival, patients with had CIC or a Mitrofanoff procedure had a significant better long-term graft survival after 10 years of follow-up (p < 0.05), despite of the existence of more recurrent UTIs in them. A better graft survival was also found in living-donor transplants (p < 0.05). No significant differences were observed in long-term graft survival regarding native kidneys or graft VUR, BA, immunosuppression regimen, or post-transplant UTIs. Conclusion: Optimal bladder dysfunction treatment, including CIC with or without a Mitrofanoff procedure, might result in better long-term graft survival in patients with PUV. These procedures were not related to a worse RT outcome in spite of being associated with more frequent UTIs.

Comparative outcome analysis of pediatric kidney transplant in posterior urethral valves children with or without pretransplant Mitrofanoff procedure

BACKGROUND

Urinary diversion using catheterizable channel among posterior urethral valve (PUV) patients may help to alleviate the functional concerns of the bladder on the allograft. Herein, we review our series of PUV patients undergoing renal transplants at a single institution to determine outcomes between those with and without pretransplant Mitrofanoff.

METHODS

PUV cases in our transplant database from 2000 to 2017 were identified. Data collected included clinical demographics, presentation of PUV, bladder function, implementation of dialysis and donor type. Post-transplant variables included graft function, and bladder function including incontinence and UTI development. Comparison between with vs without pretransplant Mitrofanoff patient groups was performed using Fisher's exact and t test analysis.

RESULTS

Overall, 22 cases were analyzed. The majority (77%) had a prenatal diagnosis of PUV, and 23% had a symptomatic presentation. Pretransplant Mitrofanoffs were performed in 40.9% of cases. The overall age at transplant was 10 ± 5 years. Five percent experienced post-transplant incontinence and 23% UTIs. No difference between groups was noted in variables including age at transplant, the timing of PUV diagnosis. Mitrofanoff group patients had more symptomatic febrile UTIs than those without Mitrofanoff (67% vs 15%; P = .03); however, there was no difference in post-transplant UTI development. Furthermore, the Mitrofanoff group seems to have later onset of dialysis or need for transplant (age at the start of dialysis 36 ± 56 vs 156 ± 25 months, P < .001).

CONCLUSION

Our study suggests that patients with early PUV diagnoses who develop symptomatic UTI may benefit from early creation of a Mitrofanoff cathetherizable channel, which is associated with delayed ESRD progression and need for dialysis.

Long-term outcome of kidney transplantation in patients with congenital anomalies of the kidney and urinary tract

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are a leading cause of end-stage kidney failure in the young. However, there is limited information on long-term outcomes after kidney transplantation in this group. We explored the outcomes of kidney transplant in patients with the 3 most common severe forms of CAKUT: posterior urethral valves (PUV), reflux nephropathy and renal hypoplasia/dysplasia.

METHODS

Data were extracted from the Australian & New Zealand Dialysis & Transplant Registry on first kidney transplants performed between 1985 and 2015 in recipients with a primary diagnosis of PUV, renal hypoplasia/dysplasia or reflux nephropathy (under the age of 30 years). Using multivariate Cox regression, we compared death-censored graft survival between the three groups.

RESULTS

One hundred twenty-seven patients with PUV, 245 with hypoplasia/dysplasia and 727 with reflux nephropathy were included. A 10-year graft survival in PUV, hypoplasia/dysplasia and reflux nephropathy was 70%, 76% and 70%, respectively and a 20-year graft survival was 30%, 53% and 49%. After adjusting for age at transplant, graft source and HLA matching, there was evidence for poorer graft survival in PUV (HR, 1.65; 95% CI, 1.15 to 2.38).

CONCLUSIONS

Graft survival of the first transplant in CAKUT is favourable at 10 years; however, recipients with PUV have increased risk of graft loss beyond a 10-year post-transplant, which may be related to bladder dysfunction.

Rare copy number variants implicated in posterior urethral valves

The cause of posterior urethral valves (PUV) is unknown, but genetic factors are suspected given their familial occurrence. We examined cases of isolated PUV to identify novel copy number variants (CNVs). We identified 56 cases of isolated PUV from all live-births in New York State (1998-2005). Samples were genotyped using Illumina HumanOmni2.5 microarrays. Autosomal and sex-linked CNVs were identified using PennCNV and cnvPartition software. CNVs were prioritized for follow-up if they were absent from in-house controls, contained ≥ 10 consecutive probes, were ≥ 20 Kb in size, had ≤ 20% overlap with variants detected in other birth defect phenotypes screened in our lab, and were rare in population reference controls. We identified 47 rare candidate PUV-associated CNVs in 32 cases; one case had a 3.9 Mb deletion encompassing BMP7. Mutations in BMP7 have been associated with severe anomalies in the mouse urethra. Other interesting CNVs, each detected in a single PUV case included: a deletion of PIK3R3 and TSPAN1, duplication/triplication in FGF12, duplication of FAT1--a gene essential for normal growth and development, a large deletion (>2 Mb) on chromosome 17q that involves TBX2 and TBX4, and large duplications (>1 Mb) on chromosomes 3q and 6q. Our finding of previously unreported novel CNVs in PUV suggests that genetic factors may play a larger role than previously understood. Our data show a potential role of CNVs in up to 57% of cases examined. Investigation of genes in these CNVs may provide further insights into genetic variants that contribute to PUV.

A case of hypospadias, anterior and posterior urethral valves

This report outlines the case of a 3-year-old boy whose initial presentation was that of asymptomatic hypertension (lowest recording 148/90), found at preoperative check prior to stage 2-correction surgery for distal hypospadias. Upon diagnosis of true hypertension, an ultrasound of the child's renal tract showed evidence of marked hydronephrosis and calyceal dilatation. On the background of deteriorating renal function (Urea 25.5 and Creatinine 188), a Micturating Cystourethrogram was performed, demonstrating posterior urethral dilatation. With difficulties controlling blood pressure, the child was transferred to Urology care, where resection of a posterior urethral valve (PUV) was undertaken. Despite this, renal function deteriorated further and re-cystoscopy identified an anterior urethral valve (AUV), which was also resected. Renal function, although improved, remains poor and blood pressure is controlled with two anti-hypertensives. To the publisher's knowledge, the association between hypospadias, PUVs and AUVs is as yet undocumented.

Impact of posterior urethral valves on pediatric renal transplantation: a single-center comparative study of 297 cases

OBJECTIVE

  This is a retrospective long-term evaluation of the renal allografts and bladder functions in pediatric recipients who had posterior urethral valves (PUV).

PATIENTS AND METHODS

Between March 1976 and February 2009, 2033 live-donor renal transplantations were carried out in our center. Of these, 297 (14.2%) were in the pediatric age (≤18 yr). The pediatric recipients included 20 (6.7%) boys who developed end-stage renal disease as a late complication of PUV and recognized as group I while the remaining 277 pediatric recipients were defined as group II. Demographic characteristics, post-transplant complications and graft function were compared among both groups. Patient and graft survivals of both groups were also estimated. Moreover, the bladder function of the study group was evaluated by urodynamic studies.

RESULTS

Patients with PUV (group I) were significantly younger than group II. Although the overall rate of urological complications in both groups was essentially similar, the incidence of urinary fistulae and urinary tract infection were higher in group I. The mean (SD) follow up periods for group I and II were 4.7 (4.1) and 6.4 (4.8) yr, respectively. At last follow up the serum creatinine values were similar among patients of both groups. Moreover, there were no differences in graft or patient survival at five and 10 yr. Detrusor over-activity could be elicited in only one of group I patients. Schafer nomogram showed non-obstructed pattern in all cases.

CONCLUSION

Good functional outcome could be achieved for patients with PUV if renal transplantation is necessary. Pre-transplant surgical procedures may be required such as nephroureterectomy, cytoplasty or injection of refluxing ureters. A robust anti-refluxing uretero-vesical anastomosis is important, and can be achieved by a Lich-Gregoir procedure.

Posterior urethral valve treatments and outcomes in children receiving kidney transplants

PURPOSE

We evaluated the impact of surgical approaches to posterior urethral valves on renal transplant survival and compared transplant survival in children with vs without posterior urethral valves.

MATERIALS AND METHODS

We reviewed the records of all children who underwent renal transplantation from January 1984 to March 2008 and performed univariate subgroup analysis in those with posterior urethral valves. We evaluated the ureteroneocystotomy method, immunosuppression and valve treatment. In patients with posterior urethral valves we regarded nocturnal and/or daytime incontinence, severe urgency and the need for intermittent catheterization or double voiding for increased post-void residual urine as signs of bladder dysfunction.

RESULTS

The initial renal transplant was received by 418 children at a mean age of 5.6 years. The 59 boys with posterior urethral valves received a total of 69 kidneys. By 8-year followup the kidney had failed in 24 of 59 boys with and 143 of 359 without posterior urethral valves (OR 0.9665, 95% CI 0.5462-1.692, p = 0.9105). Immunosuppression was consistent in the 2 groups. Outcomes were similar across all ureteroneocystotomy techniques. Initial management for posterior urethral valves was valve ablation alone in 12 boys, vesicostomy in 7 and supravesical diversion in 11. There was no difference in transplant survival or bladder dysfunction based on valve intervention. In 18 boys (55%) we noted overlapping signs of bladder dysfunction, of whom 11 performed intermittent catheterization or had increased post-void residual urine, 4 had severe urgency, 4 had daytime incontinence and 7 had nocturnal incontinence. Bladder dysfunction did not predict increased graft loss (OR 3.306, 95% CI 0.7615-16.27, p = 0.1134).

CONCLUSIONS

Of children who undergo renal transplantation boys with posterior urethral valves do not have a higher graft failure rate. Treatment for posterior urethral valves did not significantly impact transplant survival or bladder dysfunction.

Laparoscopic ureterocystoplasty before kidney transplantation

PURPOSE

To describe the technique of total laparoscopic ureterocystoplasty.

MATERIALS AND METHODS

Laparoscopic ureterocystoplasty was performed to optimize the bladder function before kidney transplantation in a 23-year-old man. This patient had undergone bilateral cutaneous ureterostomy with fulguration of a posterior urethral valve at the age of 11 months. He underwent open surgical removal of multiple renal stones at age 10. He progressed to chronic renal failure at the age of 20, at which time hemodialysis was initiated. Because of grade IV vesicoureteral reflux and a poorly compliant bladder, the patient underwent laparoscopic ureterocystoplasty.

RESULTS

The patient's lower urinary tract symptoms improved, and a urodynamic study performed after 6 months revealed a compliant bladder. Subsequently, a right nephrectomy and a live-donor renal transplantation from his mother were performed. At 1-year follow-up, his renal parameters were within normal range, he does not have any significant residual urine or urinary symptoms.

CONCLUSION

Laparoscopic ureterocystoplasty is an excellent option for a poorly compliant bladder, especially when a patient has had multiple open surgeries and is awaiting renal transplantation.

Renal transplantation in children with posterior urethral valves

The objective of this study was to analyze whether renal transplantation (RT) in children with posterior urethral valves (PUV) constitutes a special group with respect to groups with different etiologies of end-stage renal disease (ESRD). Between 1979 and 2004, 22 RT were performed in 19 children with PUV. The median age at RT was 10 years (range: 1.3-17). Immunosuppression was provided by triple therapy and polyclonal/monoclonal antibodies. This group was compared with the two control groups: (1) glomerulopathy (n=62) and (2) pyelonephritis/dysplasia (n=42) without lower urinary tract disease, transplanted in the same period. Ten graft losses occurred in 22 transplants: thrombosis (2), acute rejection (3), chronic graft nephropathy (2), and death of patients (3) with a functioning graft in the 1st postoperative month. We did not find significant differences versus the control group in renal function or probability of graft or patient survival at 1, 5, and 10 years. We observed a greater risk of urological complication in patients with PUV. RT with PUV constitutes a special group due to the compulsory young age and the need for careful and complex medicosurgical management; nevertheless, the results achieved were similar to those obtained in our general RT population.

Obstructive uropathy

Routine second trimester ultrasound screening has resulted in more infants diagnosed with antenatal hydronephrosis. Current recommendations suggest postnatal evaluation of all infants with a renal pelvic diameter >5 mm with ultrasound and voiding cystourethrogram (VCUG.) There are many etiologies of obstructive uropathy including ureteropelvic junction (UPJ) obstruction, ureterovesical junction (UVJ) obstruction, posterior urethral valves (PUV), prune belly syndrome, and vesicoureteral reflux (VUR). Obstructive uropathy can result in tubular damage and decreased nephron number. Tubular damage can result in sodium wasting, hyperkalemic acidosis, and nephrogenic diabetes insipidus. Most patients do not require renal replacement therapy in the neonatal period; however, chronic renal insufficiency can occur if the neonate has a significant reduction in nephron number or progressive renal damage from obstruction or infection.

Kidney transplantation into patients with abnormal bladders

An abnormal urinary bladder is no longer a contra-indication to renal transplantation. A normal urinary bladder stores urine at low pressure, does not leak, and empties completely by natural voiding. In contrast, an abnormal urinary bladder stores urine at high pressure, leaks, or does not empty completely by natural voiding. A variety of procedures have been devised to change the abnormal bladder into a continent low-pressure reservoir. Knowledge of these bladder modifications and their management should allow successful transplantation in patients with abnormal bladders and provide outcomes that match or approach those achieved in patients with a normal bladder.

RENAL TRANSPLANTATION IN ADULTS WITH ABNORMAL BLADDERS

Since January 1, 1985, we have performed 73 renal transplants in 66 patients with abnormal bladders who had end-stage renal failure as a consequence of urologic abnormalities (mean age 32 years). Their outcome is compared with 58 renal transplants in 54 patients (mean age 40 years) who had renal failure from primary vesicoureteric reflux or renal dysplasia and whose bladder function was considered to be normal. There is no difference in actuarial graft survival in the two groups at 10 years (abnormal 66%, normal bladders 61%), although longer follow-up is showing an advantage for normal bladders, with a kidney half-life of 29 to 33 years compared with 15 years for the abnormal bladder group. Similarly, actuarial patient survival at 10 years is 86% in both groups. Current renal function is better in the group with normal bladders. At latest follow-up, the abnormal, unaugmented bladder group (n=34) has been followed for 92 (87) months (mean [median]) and has a plasma creatinine of 178 (161) micromol/L, whereas the normal bladder group (n=33) has been followed for 104 (93) months and has a creatinine concentration of 143 (140) micromol/L. A strict policy, since 1991, of prophylactic antibiotics for the first 6 months has halved the subsequent incidence of urinary tract infection. Urinary tract infections only produced problems in patients with abnormal bladders. Renal transplantation into the abnormal lower urinary tract is successful but requires careful preoperative evaluation and posttransplant follow-up.

Successful renal transplantation in children with posterior urethral valves

PURPOSE

The treatment of children with posterior urethral valve (PUV) and end-stage renal disease can be challenging. Some series have had poor outcomes after renal transplantation with an increased risk of graft dysfunction and urinary tract infections. We present our experience with a pediatric population and compare it to all the other pediatric renal transplants done at our institution.

MATERIALS AND METHODS

We identified 10 patients with PUV who underwent a total of 13 renal transplants between 1990 and 2000. The comparison group included 120 transplants done in 95 patients during the same period. Cumulative allograft survival and function were recorded.

RESULTS

Overall patient survival in the PUV group was 100%. Mean age at transplant in the PUV group was 10.0 years and mean followup was 3.9 years. Six patients underwent high proximal urinary tract diversion, while the remainder had primary transurethral valve ablation. Three patients had bladder augmentation before transplantation. Cumulative allograft survival in the PUV group at 1 and 5 years was 85% and 64%, respectively. Of the 10 patients 9 currently have functioning living related donor transplants. One patient lost 3 cadaveric donor transplants to chronic rejection. No patients lost grafts due to infection or bladder dysfunction. Mean serum creatinine of the functioning grafts was 1.1 mg/dl.

CONCLUSIONS

Renal transplantation can be performed safely and effectively in patients with PUV, including those who have undergone previous proximal urinary tract diversion. Preoperative bladder management and continued monitoring of bladder and kidney function postoperatively are paramount in the preservation of allograft function.

Long-term results of pediatric renal transplantation into a dysfunctional lower urinary tract

BACKGROUND

The authors reviewed their long-term experience with pediatric renal transplantation into a dysfunctional lower urinary tract to evaluate the results of contemporary lower urinary tract evaluation and management on graft survival and function.

METHODS

Between 1990 and 1996, 21 renal transplants were performed in 20 children with dysfunctional lower urinary tracts and 61 transplants were performed in 61 patients with normal lower urinary tracts. The minimum follow-up was 36 months (mean, 62.0 +/- 19.6 months). The cause of lower urinary tract dysfunction included posterior urethral valves (n=13), prune belly syndrome (n=4), meningomyelocele (n=2), and urogenital sinus abnormality (n=1). Urodynamics were performed on all children with dysfunctional lower urinary tracts. Using these perioperative assessments, lower tract management strategies were devised, including timed voiding alone (n=6), clean intermittent catheterization (n=8), bladder augmentation (n=4), and supravesical urinary diversion (n=2).

RESULTS

Overall 5-year actuarial patient and graft survival rates were 100% versus 95% (P=not significant [NS]) and 83% versus 69% in the dysfunctional and normal urinary tract groups (P=NS), respectively. Mean serum creatinine levels in dysfunctional and normal urinary tract patients with functioning grafts at 3 years were 1.3 +/- 0.5 and 1.3 +/- 0.7 mg/dL, respectively (P=NS). However, 35% of patients with a dysfunctional lower urinary tract experienced urologic complications.

CONCLUSIONS

Pediatric renal transplantation into a dysfunctional lower urinary tract yields outcomes comparable to transplantation into the normal lower urinary tract. Because of the high urologic complication rates, careful surveillance of lower urinary tract function by urodynamic evaluation is essential to optimize these outcomes.

Limited surgical interventions in children with posterior urethral valves can lead to better outcomes following renal transplantation

There is currently no consensus as to the most appropriate means by which children with posterior urethral valves (PUV) are to be managed prior to transplantation. We compared (i) renal allograft survival and function in patients with PUV vs. those with non-obstructive causes of ESRD and (ii) graft outcomes in children who had limited interventions (Group 1) vs. those with more extensive urologic surgeries to decompress the urinary tract (Group 2). Twenty-six pediatric renal transplant recipients had ESRD due to PUV (Group 1, n = 16; Group 2, n = 10). The study group was compared to 23 matched controls with ESRD due to non-obstructive causes. Five yr patient and graft survival was similar in all patients with PUV (Groups 1 and 2) when compared to all other kidney recipients in the transplant program, 96.2% vs. 98.0% and 87.5% vs. 87.0%, respectively. Although calculated creatinine clearance (Ccr), was similar between the PUV group and controls for the first 4 yr, the 5 yr graft function was significantly lower in the PUV group. (53.7 +/- 15.7 vs. 70.2 +/- 21.0 mL/min/1.73 m2; p = 0.03). When the two PUV groups were compared, graft survival was equivalent, but graft function was significantly better at 5 yr in Group 1(60.4 +/- 10.8 vs. 33.8 +/- 9.3 mL/min/1.73 m2; p = 0.02). Thus, patients with PUV managed by a limited intervention approach of vesicostomy with delayed valve ablation or primary valve ablation, had better outcomes. When ESRD is virtually certain, additional pre-transplant surgeries affecting the urinary tract should be avoided.

Ureterocystoplasty (bladder augmentation) with a solitary kidney

Children who develop end-stage renal disease (ESRD) as a result of obstructive uropathies require evaluation and treatment of associated bladder dysfunction to ensure a good outcome following renal transplantation. Bladder dynamics can often be optimized medically, although surgical intervention is occasionally necessary. For those patients who require bladder augmentation, the use of a dilated native ureter (ureterocystoplasty) is preferred to the more commonly used intestine or stomach (enterocystoplasty), which carry a higher risk of complications. Unfortunately, most patients do not have a suitable anatomy for ureterocystoplasty and, by necessity, intestine or stomach has to be utilized. Herein, we describe the successful application of ureterocystoplasty in the presence of ESRD and a solitary kidney prior to renal transplantation. We believe that owing to the many advantages of native urothelium, every effort should be made to use ureter and avoid the use of intestine.

Renal transplantation

There has been an increase in the transplantation of kidneys from living, genetically unrelated donors and from extended criteria cadaver donors. The past policies about paid renal donors are being reconsidered. Techniques have been developed to reduce morbidity for the living renal donor. The variety of immunosuppressants allows individuation of therapy. Guidelines for conception and pregnancy have been established.