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

A systematic review of kidney transplantation outcomes in patients with end-stage renal disease due to childhood lower urinary tract malformations

PURPOSE

Patients with lower urinary tract malformations (LUTM) were suspended from kidney transplantation (KT) programs in the past due to various concerns. Consequently, only a limited number of studies have explored this topic at hand. In this study, our objective was to perform a systematic review (SR) to evaluate the current evidence regarding KT outcomes as well as patient survival (PS), postoperative complications and urinary tract infections (UTI) in individuals with childhood LUTM.

METHODS

The search encompassed databases of Web of Science, Medline (via PubMed), and Embase (via Scopus) to identify all studies reporting outcomes on KT for patients with LUTM. The research included articles published in English from January 1995 till September 2023.

RESULTS

Of the 2634 yielded articles, 15 met the inclusion criteria, enrolling a total of 284,866 KT patients. There was significantly better 5-year graft survival (GS) in recipients with LUTM compared to the control group (RR, 1.04; 95% CI 1.02-1.06); while GS at 1-year and 10-year, and PS at 1-year, 5-year and 10-year were similar between groups. On the other hand, the postoperative UTI rate was significantly higher in the LUTM group (RR: 4.46; 95% CI 1.89-10.51). However, data on serum creatinine and estimated glomerular filtration rate on follow-up were insufficient.

CONCLUSION

GS and PS rates appear to be similar in patients with childhood LUTM and those with normal lower urinary tract functions. Despite a higher postoperative UTI rate within this patient group, it appears that this has no effect on GS rates.

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.

Native nephrectomy in advanced pediatric kidney disease: indications, timing, and surgical approaches

In pediatric kidney failure, native kidneys may pose a risk to successful transplant outcomes. The indications and timing of native nephrectomy represent a controversial management decision. A lack of high-quality, outcomes-based data has prevented development of evidence-based guidelines for intervention. In this article, we review the published literature on medical indications for native nephrectomy and current knowledge gaps. In addition, we provide a surgical perspective regarding timing and approach.

Urodynamic changes before and after endoscopic valve ablation in boys diagnosed with the posterior urethral valve without chronic renal failure

INTRODUCTION

Current research on the posterior urethral valve (PUV) mainly focuses on the follow-up of bladder function after valve ablation. However, few studies exist on the changes in bladder function before and after valve ablation.

OBJECTIVES

To investigate the urodynamic changes before and after PUV ablation and determine the effect of operation on bladder function, in patients.

MATERIALS AND METHODS

The clinical records of 38 boys diagnosed with PUV and undergone urodynamic exams before and after valve ablation were retrospectively reviewed. In addition, differences in patients' radiographic studies and urodynamic characteristics between pre- and post-operation were evaluated. Moreover, the urodynamic data was compared using the paired t-test and all the data was expressed as means ± SEM. Additionally, p values less than 0.05 were considered to be statistically significant.

RESULTS

All the patients were diagnosed with PUV and the follow-up period after operation ranged between 9 and 114 months. The urodynamic exams were performed about 6 months after operation. The results revealed that bladder compliance improved from 8.49 ± 4.73 to 13.31 ± 6.78 ml/cmH₂O while the maximum detrusor pressure decreased from 95.18 ± 37.59 to 50.71 ± 21.71 cmH₂O, after valve ablation. Additionally, there were significant differences in the pre- and post-operation values of bladder compliance and maximum detrusor pressure (p < 0.05). However, there were no significant differences in the pre- and post-operation values with regard to the residual urine volume, maximum bladder volume and maximum urinary flow rate (p > 0.05).

CONCLUSIONS

The adequacy of the COPUM incision is necessary. But the study showed that endoscopic valve ablation couldn't by itself completely improve the bladder function of patients diagnosed with PUV. However, it was able to improve bladder compliance and decrease maximum detrusor pressure to a certain extent. However, bladder compliance still couldn't reach the normal level.

Pearls and Pitfalls in Pediatric Kidney Transplantation After 5 Decades

Worldwide, over 1,300 pediatric kidney transplantations are performed every year. Since the first transplantation in 1959, healthcare has evolved dramatically. Pre-emptive transplantations with grafts from living donors have become more common. Despite a subsequent improvement in graft survival, there are still challenges to face. This study attempts to summarize how our understanding of pediatric kidney transplantation has developed and improved since its beginnings, whilst also highlighting those areas where future research should concentrate in order to help resolve as yet unanswered questions. Existing literature was compared to our own data of 411 single-center pediatric kidney transplantations between 1968 and 2020, in order to find discrepancies and allow identification of future challenges. Important issues for future care are innovations in immunosuppressive medication, improving medication adherence, careful donor selection with regard to characteristics of both donor and recipient, improvement of surgical techniques and increased attention for lower urinary tract dysfunction and voiding behavior in all patients.

Urodynamic assessment in the management of the child's posterior urethral valves

BACKGROUND

Bladder dysfunction may be associated with valves of the posterior urethra. Their evaluation by urodynamic assessment is an important parameter for the therapeutic management. The objective of our study was to study the contribution of urodynamic assessment in the management of valves of the posterior urethra of the child.

METHODS

Our study was descriptive, retrospective, involving 43 children with posterior urethral valves (PUV), followed at the pediatric ward at Charles Nicolle Hospital in Tunis from January 1995 to December 2015. All the children had an urodynamic assessment after valves of the posterior urethra treatment.

RESULTS

The mean age was 15.8 months. Preoperatively, creatinine clearance was below 60 ml / min in 32 patients (74%). The worsening of renal function was noted in 32 (74%). A significant post-voiding residue proved in 34 patients (79%). Cystometry revealed a hypo compliant bladder in 24 (56%), low bladder capacity in 42% of cases; a hypertonic detrusor in 37% of cases. Bladder sphincter dyssynergia was diagnosed in 6 patients. Like urodynamic assessment data, bladder enlargement associated with a Mitrofanoff-type shunt was indicated and performed in 3 patients (7%).

CONCLUSION

Through our study, the urodynamic profile made it possible to specify the type of vesico-sphincter dysfunctions persistent in patients operated for PUV, and subsequently to adapt the therapeutic conduct in these patients. Given the lack of management and the consequences on the health of the child as well as on his quality of life, reflections on the preventive and therapeutic approach after PUV treatment are necessary.

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.

Outcome of a thorough screening of lower urinary tract function in all pediatric kidney recipients

LUTD is one of the possible factors influencing pediatric kidney graft outcomes. This study evaluates the results of a thorough assessment of voiding behavior in pediatric transplants. Data of patients with kidney disease of nephrological origin are compared to those with urological origin. A single-center analysis of pediatric kidney transplants performed from 2005 to the present was executed. Donor and recipient characteristics as well as voiding and drinking habits were documented using FVCs and uroflowmetry with PVR measurements. LUTD was defined by a mean MVV >150% or <65% of the EBC for age, abnormal uroflowmetry, PVR repeatedly >15% of EBC or >20 mL, abnormal voiding patterns or behavior, and presence of LUT symptoms. LUTD was diagnosed in 71% of the 56 screened children and more present in urological origin of kidney disease (100%) compared to nephrological origin (61%, P = .005). Individual presence of LUT symptoms, abnormal voiding behavior, FVC parameters, UTIs, and uroflowmetry/PVR parameters were not different between the two groups. Polyuria after transplantation was seen in 63% of patients, mainly in the first post-transplant years and recipients aged <10 years. Time after transplantation was a significant independent predictive factor for the presence of LUTD. LUTD is common in all pediatric kidney recipients and underestimated in those with a nephrological origin of disease. Active screening, monitoring and a care attention plan prior to transplantation and during follow-up, is advocated to optimize outcomes for all patients.

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.

Renal, Bladder and Sexual Outcomes in Adult Men with History of Posterior Urethral Valves Treated in Childhood

OBJECTIVE

To determine the adulthood outcomes of bladder, kidney, and sexual functions of posterior urethral valve (PUV) patients.

MATERIALS AND METHODS

The records of patients who were treated for PUV between 1980, and 2001 and aged ≥18 years by the end of 2019 were retrospectively reviewed. Patients with complete adulthood data were included in the study. Renal, bladder, and sexual functions were assessed. Adulthood uroflowmetry results of 22 patients were also evaluated.

RESULTS

Thirty-nine patients with complete adulthood data out of 89 were included. The median follow-up time was 22.7 years (15-33 years). Median age at initial surgery for PUV was 36 months (1-168 months), and median age at last follow-up was 26 years (18-46 years). Lower urinary tract dysfunction was noted in 15 (38%) patients. In 22 patients (56%) with uroflowmetric analyses, median values of Q_max, voided volume, and post voiding residual urine volume were 20.5 mL/sec (7-43 mL/sec), 389 mL (154-1750 mL), and 18.5 mL (range 0-190 mL), respectively. Nineteen patients (48.7%) had normal glomerular filtration rate, 2 patients (5.1%) had chronic kidney disease, and the remaining 18 patients (46.1%) had end stage renal disease, 14 (35.9%) of whom underwent renal transplantation. Thirty-two patients (82%) had sexual function evaluation, none of which reported erectile dysfunction. However, 4 patients (12.5%) reported slow ejaculation. Five patients fathered a child whereas infertility was observed in 2 patients.

CONCLUSION

After 2 decades, glomerular filtration rate was normal almost in half of the PUV patients while lower urinary tract dysfunction was detected in 38%. Furthermore, erectile dysfunction was rare.

Serum creatinine levels in cases of posterior urethral valve: 29 years experience of a pediatric urology reference center

OBJECTIVES

The aim of this retrospective study is to describe the importance of serum creatinine levels for the long-term renal outcome in cases of posterior urethral valve.

METHODS

Records of 94 patients who underwent cystoscopic valve ablation were evaluated retrospectively. Demographic variables, radiologic findings, and serum creatinine levels were recorded. Patients were grouped according to the serum creatinine levels in the first month of life. Twenty-four patients' serum creatinine levels were found to be above 1 mg/dL in group 1 and ≤1 mg/dL in 70 patients in group 2.

RESULTS

The initial findings of 74 patients were as follows: pyelonephritis in 24 (32.43%) patients, hydronephrosis in 20 (27.02%), and inability to urinate in 18 (24.32%). Prenatal hydronephrosis was present in 36 cases (38.29%). Of the 92 voiding cystograms, 53.26% had findings that included vesicoureteral reflux. The mean serum creatinine levels of the patients in group 1 increased above 1 mg/dL in the 2nd year, the significant difference between the two groups lasted up to 7 years of age, and no significant difference was observed at the age of 7. The mean serum creatinine levels of the patients in group 2 were observed to increase above 1 mg/dL by the 10th year.

CONCLUSIONS

In patients with posterior urethral valves, nadir creatinine, especially higher than 1 mg/dL, should be considered as high risk for end-stage renal disease. Therefore, clinicians should improve awareness about early detection and treatment of posterior urethral valves, and these patients should be monitored as early as possible for the risk of chronic kidney disease.

Long-term growth in children with posterior urethral valves

BACKGROUND

Posterior urethral valves (PUVs) are one of the leading causes of pediatric chronic kidney disease (CKD). Growth impairment is prevalent in pediatric CKD, and children with PUVs are at high risk for growth retardation.

OBJECTIVE

The objective of this study was to describe growth profiles in PUVs and to identify risk factors for stunting, defined as age-specific height standard deviation score (SDS) below -2.

PATIENTS AND METHODS

Medical records of 65 patients with PUVs and a minimum follow-up of two years were retrospectively reviewed. Chronic kidney disease stage 1-3 was considered mild CKD, whereas CKD stage 4-5 was considered advanced CKD. Age-specific height, weight, and body mass index (BMI) SDS were determined. Seven potential risk factors for stunting, namely timing of diagnosis, renal dysplasia, timing of surgery, requirement of urinary diversion, nadir serum creatinine after surgery, recurrent febrile urinary tract infection (UTI), and severity of CKD, were analyzed.

RESULTS

Median age at diagnosis, at surgery, and at last follow-up was 0.51, 0.75, and 7.53 years, respectively. All patients underwent valve ablation, and 33.8% required urinary diversion. Median nadir serum creatinine after surgery was 0.40 mg/dL and was higher in patients who underwent urinary diversion (P < 0.001). Growth profiles by CKD stage are displayed in Fig. 1. Median height SDS was -0.40 and was lower in patients with advanced CKD (P = 0.03). Stunting was diagnosed in 15.4%. Advanced CKD was an independent risk factor for stunting, with the odds ratio of 12.7. Urinary diversion and nadir creatinine more than 0.80 mg/dL were weakly associated with stunting but not significant. Timing of diagnosis and surgery, unilateral renal dysplasia, and recurrent febrile UTI were not associated with stunting. Median SDS of weight and BMI was -0.64 and -0.19, respectively. Patients who were thin, of normal weight, overweight, and obese comprised 26.2%, 58.5%, 10.8%, and 4.6%, respectively. There was no significant difference of SDS of weight and BMI across CKD stages (Fig. 1).

DISCUSSION

Deterioration in height began early in the course of disease and was worsening in relation to the decline of renal function. The impact of timing of diagnosis or surgery on height was controversial. Patients who underwent urinary diversion had high nadir creatinine and were likely to have severe PUVs. Although patients with severe baseline renal dysfunction may require urinary diversion, nadir serum creatinine and urinary diversion are not associated with stunting. Delaying progression of CKD could maximize linear growth potential in PUVs. A substantial proportion of patients were overweight or obese. Sufficient caloric intakes may be maintained in patients with PUVs.