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

Role of vesicoureteral reflux on pediatric kidney allograft function

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Clinical considerations in adults with history of posterior urethral valves

INTRODUCTION

Management of patients with posterior urethral valves (PUV) is commonplace for many pediatric urologists, however adult providers may be far less familiar with this diagnosis, its management and long-term ramifications. As urologic management of these patients has evolved, clinical outcomes have substantially improved with many more patients now surviving into adulthood. These patients remain at increased risk of morbidity due to their condition and therefore are likely to benefit from long term follow-up with adult providers.

OBJECTIVE

In this review we analyze the psychosocial impacts of PUV on adults, evaluate long term transplant outcomes in PUV patients and discuss effective clinical management strategies of bladder dysfunction in adult PUV patients.

STUDY DESIGN

A retrospective literature review was performed using the MEDLINE (Pubmed) electronic database using key words such as "posterior urethral valve", "quality of life", "sexual function", "transplant outcomes", "bladder dysfunction", "mitrofanoff" etc. to identify relevant studies.

RESULTS

Generally, the quality of life of PUV patients is good, those suffering from renal insufficiency or lower urinary tract symptoms, specifically incontinence, appear to be a group that may benefit from more intensive follow-up. Good long-term kidney transplant (KT) function and survival can be achieved in patients with PUV. Rigorous management to optimize bladder function and close follow-up, are key for long term graft survival after KT.

DISCUSSION

The chronicity of PUV warrants adult providers to be not only well versed in the pathophysiology of the disease, but well prepared to care for these patients as they transition into adulthood.

CONCLUSION

Additional studies addressing psychosocial, clinical and transplant outcomes of adults with PUV are necessary to develop optimal long-term follow-up regimens for these patients.

Prenatal diagnosis and outcome of fetal urinomas in relation to the underlying etiology

OBJECTIVE

Evaluation of course and outcome of pregnancies with prenatally diagnosed fetal urinoma in a single center over a 20-year period.

METHODS

Retrospective study including all prenatally suspected or diagnosed fetal urinomas. Cases were analyzed by ultrasound findings during pregnancy, comparing urinomas caused by lower urinary tract obstruction (LUTO) and ureteropelvic or ureterovesical junction obstruction (UPJO/UVJO). Course of pregnancy and outcomes were compared according to the underlying etiology.

RESULTS

87 cases of fetal urinomas were identified between 2002 and 2022. The underlying etiology was LUTO in 56.3% and UPJO/UVJO in 43.7%. Complications mainly included oligo- or anhydramnios, thoracic hypoplasia as well as associated renal abnormalities. Postnatally, loss of function (LOF) in kidneys affected by urinomas was seen in 78.6% of children overall, but significantly more often in cases of UPJO/UVJO than in LUTO (86.2% vs. 70.2%, p < 0.05).

CONCLUSION

Association of prenatal urinoma and postnatal LOF of the affected kidney is high, especially in cases caused by UPJO/UVJO. In survivors with urinoma caused by UPJO/UVJO, the general prognosis is excellent if the contralateral kidney was normal. In survivors with urinomas caused by LUTO, long-term prognosis depends on postnatal renal and pulmonary function.

Development and validation of a novel fetal vesico-amniotic shunt, the vortex shunt

Fetal lower urinary tract obstruction (LUTO) is a severe malformation associated with an up to 80% mortality risk as well as significant renal and pulmonary morbidity in survivors. Fetal vesico-amniotic shunts (VAS) bypass the bladder obstruction, improve amniotic fluid volume and enhance in-utero pulmonary development. VAS has been shown to reduce respiratory morbidity and mortality in the neonatal period without proven benefit on long-term renal and bladder function. Clinically available shunts are associated with an up to 80% dislodgement rate, leading to repeat invasive procedures which increase fetal and maternal risks. We developed a novel "Vortex" shunt, which incorporates enhanced fixation to reduce dislodgement, a one-way valve to optimize in-utero bladder function, and enhanced sonographic echogenicity that optimizes the accurate deployment. Following the validation of these characteristics in initial benchtop experiments we have moved to feasibility studies in the fetal lamb model. We hope that the Vortex shunt may ultimately facilitate shunt deployment, reduce dislodgement risk, improve neonatal morbidity and mortality, and decrease the significant healthcare expenditures associated with long-term morbidity in LUTO survivors. In this manuscript, we review the natural history of LUTO, the risks and benefits of clinically available fetal shunts, and our development and early validation experiments.

Congenital Anomalies of the Kidney and Urinary Tract: A Continuum of Care

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of kidney failure in children and adolescents. CAKUT describes a wide spectrum of structural disorders with a prenatal origin. The etiology of CAKUT is multifactorial, including environmental, nongenetic, and genetic causes that impact kidney development as well as upper and lower urinary tract development. Adult nephrologists who treat patients with CAKUT may be challenged by the underlying diseases they are not familiar with and the accumulation of chronic kidney disease complications in childhood. This article discusses CAKUT etiology and presentation, the course during childhood and adolescence, as well as adult issues in CAKUT patients including CKD complications, urologic interventions, and genetic counseling. A smooth transition of CAKUT patients from pediatric to adult care can be challenging. Semin Nephrol 43:x-xx © 2023 Elsevier Inc. All rights reserved.

Ureterocystoplasty in Boys with Valve Bladder Syndrome-Is This Method Still up to Date?

Boys with valve bladder syndrome (PUV) require adequate treatment of the lower urinary tract to preserve renal function and improve long-term outcomes. In some patients, further surgery may be necessary to improve bladder capacity and function. Ureterocytoplasty (UCP) is usually carried out with a small segment of intestine or, alternatively, with a dilated ureter. Our aim was to evaluate the long-term outcomes after UCP in boys with PUV. UCP had been performed in 10 boys with PUV at our hospital (2004-2019). Pre- and postoperative data were evaluated in relation to kidney and bladder function, the SWRD score, additional surgery, complications, and long-term follow-up. The mean time between primary valve ablation and UCP was 3.5 years (SD ± 2.0). The median follow-up time was 64.5 months (IQR 36.0-97.25). The mean increase in age-adjusted bladder capacity was 25% (from 77% (SD ± 0.28) to 102% (SD ± 0.46)). Eight boys micturated spontaneously. Ultrasounds showed no severe hydronephrosis (grade 3-4). The SWRD score showed a median decrease from 4.5 (range 2-7) to 3.0 (range 1-5). No conversion of augmentation was required. UCP is a safe and effective approach to improve bladder capacity in boys with PUV. In addition, the possibility of micturating naturally is still maintained.

Renal transplantation in pediatric recipients: Considerations and preoperative assessment strategies

INTRODUCTION AND OBJECTIVE

Renal transplantation in the pediatric population differs from adults in many aspects. This review will focus on the unique issues of the pediatric recipient.

MATERIAL AND METHODS

A narrative review on the scarce literature regarding preoperative evaluation before kidney transplantation of the paediatric recipient with an educational focus was conducted. The literature search allowed for identification of publications in English from January 2000 to October 2022. Published studies were identified by searching the following electronic databases: PubMed (MEDLINE), WHO/UNAIDS, Google-Scholar, Semantic-Scholar and Research Gate. For efficiency and reliability, recent randomized controlled trials, meta-analyses, high quality systematic reviews and large well-designed studies were used if available. Internet searches were conducted for other relevant information (definitions, policies or guidelines).

RESULTS

Management of congenital urogenital anomalies and lower urinary tract dysfunction along with optimal pediatric urological preoperative assessment for renal transplantation in children is addressed in the light of the available literature. Furthermore, particular considerations including pre-emptive transplantation, transplantation of an adult-size kidney into an infant or small child is discussed.

CONCLUSIONS

Outcomes of RT in children have shown progressive improvement over the past 15 years. Transplantation with living related donor gives the best results and pre-emptive transplantation provides with benefits of avoiding dialysis. Surgical and medical considerations in both the pre-transplant and post-transplant management of the pediatric kidney recipient are extremely crucial in order to achieve better short and long-term results.

Chronic Kidney Disease in Boys with Posterior Urethral Valves-Pathogenesis, Prognosis and Management

Posterior urethral valves (PUV) are the most common form of lower urinary tract obstructions (LUTO). The valves can be surgically corrected postnatally; however, the impairment of kidney and bladder development is irreversible and has lifelong implications. Chronic kidney disease (CKD) and bladder dysfunction are frequent problems. Approximately 20% of PUV patients will reach end-stage kidney disease (ESKD). The subvesical obstruction in PUV leads to muscular hypertrophy and fibrotic remodelling in the bladder, which both impair its function. Kidney development is disturbed and results in dysplasia, hypoplasia, inflammation and renal fibrosis, which are hallmarks of CKD. The prognoses of PUV patients are based on prenatal and postnatal parameters. Prenatal parameters include signs of renal hypodysplasia in the analysis of fetal urine. Postnatally, the most robust predictor of PUV is the nadir serum creatinine after valve ablation. A value that is below 0.4 mg/dl implies a very low risk for ESKD, whereas a value above 0.85 mg/dl indicates a high risk for ESKD. In addition, bladder dysfunction and renal dysplasia point towards an unbeneficial kidney outcome. Experimental urinary markers such as MCP-1 and TGF-β, as well as microalbuminuria, indicate progression to CKD. Until now, prenatal intervention may improve survival but yields no renal benefit. The management of PUV patients includes control of bladder dysfunction and CKD treatment to slow down progression by controlling hypertension, proteinuria and infections. In kidney transplantation, aggressive bladder management is essential to ensure optimal graft survival.

Posterior urethral valves: Role of prenatal diagnosis and long-term management of bladder function; a single center point of view and review of literature

Posterior Urethral Valves (PUV) are the most common cause of lower urinary tract obstruction. More severe forms are detected early in pregnancy (mainly type I), while other forms are usually discovered later in childhood when investigating lower urinary tract symptoms. Bladder dysfunction is common and is associated with urinary incontinence in about 55% (0%-72%). Despite the removal of the obstruction by urethral valve ablation, pathological changes of the urinary tract can occur with progressive bladder dysfunction, which can cause deterioration of the upper urinary tract as well. For this reason, all children with PUV require long-term follow-up, always until puberty, and in many cases life-long. Therefore, management of PUV is not only limited to obstruction relief, but prevention and treatment of bladder dysfunction, based on urodynamic observations, is paramount. During time, urodynamic patterns may change from detrusor overactivity to decreased compliance/small capacity bladder, to myogenic failure (valve bladder). In the past, an aggressive surgical approach was performed in all patients, and valve resection was considered an emergency procedure. With the development of fetal surgery, vesico-amniotic shunting has been performed as well. Due to improvements of prenatal ultrasound, the presence of PUV is usually already suspected during pregnancy, and subsequent treatment should be performed in high-volume centers, with a multidisciplinary, more conservative approach. This is considered to be more effective and safer. Primary valve ablation is performed after clinical stability and is no longer considered an emergency procedure after birth. During childhood, a multidisciplinary approach (pediatric urologist, nephrologist, urotherapist) is recommended as well in all patients, to improve toilet training, using an advanced urotherapy program with medical treatments and urodynamic evaluations. The aim of this paper is to present our single center experience over 30 years.