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

Antenatal and postnatal management of posterior urethral valves: where do we stand?

Introduction

Posterior urethral valve (PUV) is the leading etiology of lower urinary tract obstruction (LUTO) in boys and is an important cause of end-stage renal disease (ESRD) in children. The aim of this article is to review the current status on antenatal intervention for PUV as well as postnatal medical and surgical management.

Main body

MEDLINE, EMBASE, Pubmed and Google Scholar search was conducted throughout December 2020 using the keywords: posterior urethral valves, congenital urinary obstruction, antenatal, valve bladder syndrome, medical, anticholinergics, alpha blocker, antibiotics, biofeedback, diversion, augmentation cystoplasty and renal transplantation. Only papers written in English were included. The relevant literature was summarized. Despite advances in antenatal intervention for fetal LUTO, it remains associated with considerable fetal and maternal morbidity. Patient selection criteria for antenatal intervention are greatly debated. Fetal intervention has resulted in improved perinatal survival in properly selected cases, with a questionable benefit to postnatal renal function. There is decent evidence supporting the use of anticholinergics in infants and young children following valve ablation, with less robust evidence advocating alpha blockers, overnight catheter drainage and biofeedback. The role of urinary diversion remains contentious. Optimizing bladder dynamics is crucial for successful renal transplantation outcomes.

Conclusion

While antenatal intervention has failed to improve renal function outcomes of PUV, patient-centered medical and sometimes surgical interventions can help delay the progression of chronic kidney disease. Lifelong monitoring and management of the associated bladder dysfunction is indispensable even after successful renal transplantation.

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.

Long-term outcome of pediatric renal transplantation in boys with posterior urethral valves

PURPOSE

To determine whether there is a difference in the outcome of renal transplantation (RT) in patients with posterior urethral valves (PUV) and children with non-uropathy related end stage renal disease.

METHODS

Data were acquired retrospectively. We analyzed possible factors that influence the function of renal allografts and graft survival. Between 1995 and 2016 there were 149 RT. Out of them, there were 27 boys with PUV, who received 29 kidneys. Thirty patients, who received a total of 31 renal grafts due to a non-uropathic (NU) diagnosis, served as control group. Mean follow-up was 7.4 to 10.2 years.

RESULTS

There was no difference in estimated graft survival between patients with PUV and NU patients. Graft failure occurred in 23.1% of PUV patients and 34.5% patients of the NU group. There was no statistically significant disparity in graft function between the two groups. Age at transplantation and donor age were the only factors that had a significant impact on renal function. There was a higher incidence of UTI in the PUV group (96%) than in the NU group (67%). Vesicostomy was the favourable intervention in regards of graft function.

CONCLUSIONS

RT in PUV patients is successful with the same outcome as in NU patients. Bladder dysfunction may not have a major impact on graft function and graft survival. It seems that the type of pre-transplant surgical procedures may influence outcome. Therefore, these interventions -if necessary- should be limited to a minimum.

TYPE OF STUDY

Retrospective Comparative Study LEVEL OF EVIDENCE: Level III.

Pre-transplant management of valve bladder: a critical literature review

OBJECTIVE

Indications, timing and problems related to augmentation cystoplasty (AC), in the context of posterior urethral valves (PUV) and renal transplantation (RT) are ill defined. Associated bladder dysfunction (BD) is not a stable condition and may cause the loss of the renal graft. Polyuria, accentuates BD and seems to improve after RT. The objective of this research is to critically review the available literature, aiming to rationalize the treatment of PUV with BD in the context of end stage renal disease (ESRD).

MATERIALS AND METHODS

A thorough literature review was performed. Pertinent papers were, critically analyzed and classified according to the level of evidence.

RESULTS

Data relating to PUV, RT and AC showed low levels of evidence. Results of RT in PUV cases with adequate management of BD were comparable to those suffering from other causes of ESRD. Bladder function can recover spontaneously after urinary undiversion. There were no established criteria to indicate AC in the context of ESRD and PUV or to define the ideal protocol to treat associated vesicoureteral reflux (VUR). Urinary tract infections (UTIs) were more frequent in transplanted PUV patients; this is possibly related to the inadequate control of BD, especially after AC. AC is feasible after RT with outcomes comparable to preemptive ones.

CONCLUSION

AC increases the risk of UTI after RT. Preemptive AC should be constructed only if the risks associated with increased bladder pressures exceed those associated with AC. Adequate management of BD is essential to improve bladder function and to minimize UTIs. AC is feasible after RT, with complication rates similar to the ones performed beforehand. Since a considerable number of PUV patients with high-pressure bladders eventually develop myogenic failure, it seems logical to postponing AC in this population, as long as they are under close surveillance.

Risk factors for renal insufficiency in children with urethral valves

Posterior urethral valves (PUV) associated with renal dysplasia are one of the most common causes of end stage kidney disease (ESKD) in childhood. In order to identify risk factors for the progression of this condition to early renal failure, we have retrospectively analyzed the clinical course, renal function, and first postnatal renal ultrasound in a sample of 42 young male patients with PUV, who were followed at a single center. Twelve (28.6%) were diagnosed with ESKD at a median age of 11.3 years. Our comparison of PUV patients without decreased estimated glomerular filtration rate (eGFR) (group A; K/DOQI CKD stage 0-1) with PUV patients showing a decreased eGFR (group B; K/DOQI CKD stage 2-5) revealed the following significant risk factors for loss of eGFR: renal volume <3rd percentile (P < 0.001), elevated echogenicity (P = 0.001), pathologic corticomedullary differentiation (P < 0.001), >3 febrile urinary tract infections (P = 0.012), and decreased eGFR at 1 year of age (P < 0.001). Receiver operating characteristic curve analysis in the cohort confirms that patients showing a renal volume >88.2 ml/m(2) body surface area (BSA) are not at risk to develop K/DOQI CKD stage 5 (sensitivity 75%, specificity 77.3%, positive/negative predictive value 37.5/94.4%). Ultrasound promises to be a valuable tool for identifying endangered patients.

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.

Disease recurrence in paediatric renal transplantation

Renal transplantation (Tx) is the treatment of choice for end-stage renal disease. The incidence of acute rejection after renal Tx has decreased because of improving early immunosuppression, but the risk of disease recurrence (DR) is becoming relatively high, with a greater prevalence in children than in adults, thereby increasing patient morbidity, graft loss (GL) and, sometimes, mortality rate. The current overall graft loss to DR is 7-8%, mainly due to primary glomerulonephritis (70-80%) and inherited metabolic diseases. The more typical presentation is a recurrence of the full disease, either with a high risk of GL (focal and segmental glomerulosclerosis 14-50% DR, 40-60% GL; atypical haemolytic uraemic syndrome 20-80% DR, 10-83% GL; membranoproliferative glomerulonephritis 30-100% DR, 17-61% GL; membranous nephropathy approximately 30% DR, approximately 50% GL; lipoprotein glomerulopathy approximately 100% DR and GL; primary hyperoxaluria type 1 80-100% DR and GL) or with a low risk of GL [immunoglobulin (Ig)A nephropathy 36-60% DR, 7-10% GL; systemic lupus erythematosus 0-30% DR, 0-5% GL; anti-neutrophilic cytoplasmic antibody (ANCA)-associated glomerulonephritis]. Recurrence may also occur with a delayed risk of GL, such as insulin-dependent diabetes mellitus, sickle cell disease, endemic nephropathy, and sarcoidosis. In other primary diseases, the post-Tx course may be complicated by specific events that are different from overt recurrence: proteinuria or cancer in some genetic forms of nephrotic syndrome, anti-glomerular basement membrane antibodies-associated glomerulonephritis (Alport syndrome, Goodpasture syndrome), and graft involvement as a consequence of lower urinary tract abnormality or human immunodeficiency virus (HIV) nephropathy. Some other post-Tx conditions may mimic recurrence, such as de novo membranous glomerulonephritis, IgA nephropathy, microangiopathy, or isolated specific deposits (cystinosis, Fabry disease). Adequate strategies should therefore be added to kidney Tx, such as donor selection, associated liver Tx, plasmatherapy, specific immunosuppression protocols. In such conditions, very few patients may be excluded from kidney Tx only because of a major risk of DR and repeated GL. In the near future the issue of DR after kidney Tx may benefit from alternatives to organ Tx, such as recombinant proteins, specific monoclonal antibodies, cell/gene therapy, and chaperone molecules.

Kidney transplantation in abnormal bladder

Structural urologic abnormalities resulting in dysfunctional lower urinary tract leading to end stage renal disease may constitute 15% patients in the adult population and up to 20-30% in the pediatric population. A patient with an abnormal bladder, who is approaching end stage renal disease, needs careful evaluation of the lower urinary tract to plan the most satisfactory technical approach to the transplant procedure. Past experience of different authors can give an insight into the management and outcome of these patients. This review revisits the current literature available on transplantation in abnormal bladder and summarizes the clinical approach towards handling this group of difficult transplant patients. We add on our experience as we discuss the various issues. The outcome of renal transplant in abnormal bladder is not adversely affected when done in a reconstructed bladder. Correct preoperative evaluation, certain technical modification during transplant and postoperative care is mandatory to avoid complications. Knowledge of the abnormal bladder should allow successful transplantation with good outcome.

Deceased-donor kidney transplantation in prune belly syndrome

OBJECTIVES

To present the long-term outcome of deceased-donor kidney transplantation in prune belly syndrome (PBS). All the PBS transplant patients had undergone extensive pretransplant urologic tract preparation. We also compared the patient and graft survival in an age-matched control group who underwent transplantation for end-stage renal disease due to a nonposterior urethral valve in our urology department.

METHODS

From 1988 to 2003, 11 kidneys were transplanted in 8 male patients with PBS. The mean age was 13.5 years (range 4 to 32). Patient and graft survival were assessed and compared with that of a group of 103 deceased-donor kidney transplantations performed in 86 age-matched controls who underwent transplantation because of end-stage renal disease due a nonposterior urethral valve (mean age 13.9 years, range 1.7 to 20).

RESULTS

In the PBS group, a total of 23 pretransplant urologic procedures were performed. One operation was performed in 1 patient, two in 2, three in 2, and four in 3 patients. In the PBS group, after transplantation, adequate bladder function was maintained by intermittent catheterization in 4 patients and timed voiding in 3; 1 patient had undergone pretransplant ileal conduit formation. Up to 10 years after transplantation, we found no difference in patient and graft survival between the two groups (P = 0.466 and P = 0.838, respectively).

CONCLUSIONS

Aggressive pretransplant urologic tract preparation and keeping the postvoid residual urine volume to a minimum are needed in patients with PBS. With such management, the outcome of kidney transplantation in our patients with PBS was not different from that of other patients who underwent transplantation for other causes of end-stage renal disease in our department.

Pediatric renal transplantation with considerations for successful outcomes

Renal transplantation in the pediatric population, although conceptually similar to that in adults, differs in many aspects. This review will focus on the issues unique to the pediatric recipient. In particular, we will focus on the incidence and etiology of end stage renal disease in children, and the results as measured by patient and graft survival. Pretransplant surgical considerations of timing of the transplant, management of congenital urologic abnormalities and the abnormal bladder will be addressed. Etiologies of renal failure unique to the pediatric population will be discussed, including autosomal recessive polycystic kidney disease, congenital nephrotic syndrome, inferior vena cava thrombosis, and primary hyperoxaluria Type 1. Lastly, special transplant surgical considerations including transplantation of an adult-size kidney (ASK) into an infant or small child and ureteral implantation, management of the urinary bladder, and fluid management in infants and small children will be discussed.

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.

RENAL TRANSPLANTATION IN CHILDREN WITH RECONSTRUCTED BLADDERS

In this article, we review the outcome and complications of renal transplantation in patients with reconstructed bladders and address specific issues and controversies regarding the management of such cases. Twenty-five articles covering the subjects of renal transplantation, lower urinary tract anomalies, and bladder reconstruction have been selected. Although urologic complications are higher when kidneys are transplanted into reconstructed bladders or urinary diversions, the graft and patient survival rates in most series are comparable with those transplanted into nonreconstructed bladders. The reported series of renal transplantation into abnormal bladders are small, and controlled studies are lacking. Bladder reconstruction should be performed before transplantation when clinically indicated.

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.