Vesicoureteral Reflux in Conjunction With Posterior Urethral Valves

Pop-off mechanisms as renoprotective mediators in children with posterior urethral valves: A systematic review and meta-analysis

BACKGROUND

Pop-off mechanisms are potential pressure-relieving mediators in patients diagnosed with posterior urethral valves (PUV). This systematic review aimed to synthesize the existing evidence regarding the protective effect of pop-off mechanisms on renal function in children with PUV.

METHODS

We conducted a systematic review of the literature that involved an extensive search in the main databases of the medical bibliography. Three independent reviewers selected the relevant articles. Methodological quality was rated using the Newcastle Ottawa Scale index. We used random meta-analyses to compare different outcomes (serum creatine, Nadir serum creatinine, and Chronic Kidney Disease) between children with PUV and pop-off mechanisms and those with PUV without pop-off mechanisms.

RESULTS

10 studies with data from 896 participants were included in this review. Seven articles reported serum creatinine values for each group and 3 of them found significant differences between groups. The random-effects meta-analysis for serum creatinine showed significant lower mean (diff = -52.88 μmol/L [95 % CI -73.65 to -32.11]) in the group of children with pop-off mechanisms, and the random-effects meta-analysis for Nadir serum creatinine showed a marginally significantly lower mean in the group of children with pop-off mechanisms (diff = -12.00 μmol/L [95 % CI -24.04 to 0.04]). The random-effect meta-analysis for Chronic Kidney Disease resulted in a significant risk reduction for the group of children with pop-off mechanisms (odds ratio = 0.48 [95 % CI 0.23 to 0.98]).

CONCLUSIONS

Children with PUV and pop-off mechanisms show better renal function and lower risk of Chronic Kidney Disease than those with PUV without pop-off mechanisms suggesting these mechanisms may act as renoprotective mediators. The high heterogeneity between studies in the assessment of renal function and long-term outcomes calls for a cautious interpretation of these findings. Future studies that stratify by different types of pop-off mechanisms and use standardized metrics, such as Nadir creatinine, are needed.

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.

Outcome of PUV Patients Following Ablation in a Tertiary Teaching Hospital in Addis Ababa, Ethiopia

Background

Posterior urethral valve  (PUV) is the most common cause of congenital lower urinary tract obstruction in boys. It is considered that early diagnosis and intervention have good outcomes in terms of renal function, though the varying extent of embryological insult requires these boys to remain in extended follow-up and care.

Objective

To assess the renal outcome of patients following PUV ablation.

Methods

This was a descriptive retrospective study. Data were collected from the operation logbooks of patients from 2015 to 2019 that had been admitted to the Tikur Anbessa Specialized Hospital pediatric surgery unit with a working diagnosis of PUV and had ablation done primarily or following diversion. Data were collected from January to April 2020 and analyzed using SPSS 25. P value≤0.05 was considered significant.

Results

Seventy patients were analyzed and followed for 3 years for the development of postoperative chronic kidney disease (CKD) after PUV ablation. Postoperative CKD was found in 52.9% of patients and end-stage renal disease in 2.9%. Risk factors associated with postoperative CKD were the presence of preoperative and postoperative proteinuria, postoperative hypertension, and elevated nadir serum creatinine. Results also showed that a delay between the development of vesicostomy and ablation had a significant correlation with renal outcome. Elevated nadir serum creatinine, postoperative proteinuria, and delay between the development of vesicostomy and ablation were found to be independent risk factors of development of CKD.

Conclusion

There was a high rate of CKD development in patients who had had ablation for PUV, which was comparable to other studies. Three variables were found to be independent risk factors for the progression of CKD, unlike other findings seen in low- and middle-income countries.

The posterior urethral valves revisited: embryological correlation, clinical classification, and risk stratification of the spectrum

Background

The diagnosis of posterior urethral valves (PUV) encompasses a vast spectrum of disease with variable severity and clinical features. It is vital to understand the extent of developmental insult and to define the different distinct entities grouped together under the diagnostic umbrella of PUV. This would help to determine the severity of the disease, enable better prognostication, and optimize therapy. The objective of this study is to analyze the variable features of PUV and correlate the different manifestations with the embryological development of the urinary system. The possible developmental basis of anomalies in PUV is analyzed, as recognition of the underlying defect would help to determine the severity of the disease. A clinical classification and a risk stratification approach encompassing the spectrum of PUV is proposed, to help define diagnosis and guide prognosis. A combined retrospective and prospective analysis of cases diagnosed as PUV at the tertiary teaching institute over a 5-year period from July 2014 to July 2019 was done. The outcome of selected cases was analyzed, based on the risk group stratification.

Results

The incidence of major complications during follow-up in each risk group was assessed individually and found to be highest in the high-risk group (92%), which was significantly higher than the other groups. The intermediate risk group was found to have a complication rate of 38%, while the low-risk group had only 12.5% complication rate. The three key concepts addressed in this study pertain to the embryological basis of PUV, the necessity of a clinical subdivision of patients, and the possibility of risk stratification based on clinical criteria. The limited review of institutional series is added to highlight the method of risk stratification and its probable utility.

Conclusions

The most critical factors to be accounted for in the diagnosis and management of PUV are the definition of disease severity, recognition of systemic complications, and identification of children at risk of progression to ESRD. The proposed developmental defect analysis, description of PUV sequence, clinical classification, and risk stratification approach are only the means to this end of segregating patient groups within the diagnostic spectrum.

Consensus on the Management of Posterior Urethral Valves from Antenatal Period to Puberty

The need for successful management of posterior urethral valves always captivates the minds of pediatric surgeons. Its success, however, depends on several factors ranging from prenatal preservation of upper tracts to postoperative pharmacological compliance. Regardless of measures available, some cases do not respond and progress to end stage. The management depends on several issues ranging from age and severity at presentation to long-term follow-up and prevention of secondary renal damage and managing valve bladder syndrome. This article is based on a consensus to the set of questionnaires, prepared by research section of Indian Association of Paediatric Surgeons and discussed by experienced pediatric surgeons based in different institutions in the country. Standard operating procedures for conducting a voiding cystourethrogram and cystoscopy were formulated. Age-wise contrast dosage was calculated for ready reference. Current evidence from literature was also reviewed and included to complete the topic.

All grown up: A transitional care perspective on the patient with posterior urethral valves

N/A

Cystometrogram appearance in PUV is reliably quantified by the shape,wall, reflux and diverticuli (SWRD) score, and presages the need for intervention

OBJECTIVE

Radiological bladder abnormalities in boys with posterior urethral valves (PUV) are well recognised; however, the assessment is subjective. The shape, wall, reflux and diverticuli (SWRD) score objectively assesses shape, wall, reflux and diverticuli in a simple way. This study was undertaken to demonstrate that the SWRD score is reliable, reproducible and correlates with bladder outcome and videourodynamic (VUD) assessment in boys with PUV.

MATERIALS AND METHODS

Three blinded assessors determined the SWRD scores of PUV bladders from cystometrograms taken during VUD from September 2012 to October 2013. The scores were correlated with clinical outcome and VUD pressure measurements. Data were given as median (interquartile range), non-parametric tests used as appropriate (Mann-Whitney U test, or Kruskall-Wallis) and P < 0.05 was taken as significant.

RESULTS

A total of 55 boys with PUV underwent VUD assessment, for which 52 cystometrograms were available. The SWRD score for non-operative management was 1.0 (0.1-1.9) vs 2.0 (1.0-3.3) for operative intervention, P = 0.018 (Summary Figure). The SWRD score for compliant bladders was 1.1 (0.6-2.0) vs hypercompliant 1.7 (0.5-2.8) vs non-compliant 3.3 (2.8-5.0), Kruskall-Wallis P = 0.011. The hostile detrusor overactivity (DO) bladders (Pdet >40 cmH₂O) had a SWRD score of 2.0 (1.3-3.7) vs 1.0 (0.5-2.5) for low-pressure DO bladders, P < 0.05.

DISCUSSION

In this series of patients, increasingly distorted bladder shape was seen to be associated with poor bladder dynamics on VUD. Patients with poorly compliant bladders had a significantly higher SWRD score than normal or megacystis patients. Severe DO was also significantly associated with a high SWRD score. Therefore, the radiological appearance of a hostile bladder represented a marker for high intravesical pressure. VUR and bladder diverticuli may lead to spurious pressure measurements during VUD; however, the SWRD score provided an independent mechanism with which to objectively assess these patients, even in the presence of gross VUR.

CONCLUSIONS

The SWRD score is a simple and objective scoring system for the radiological abnormalities of PUV bladders. It correlates with clinical outcome and VUD assessment of compliance and DO, but is independent of pressure measurements and so not confounded by VUR acting as a 'pop-off' mechanism.

Outcome of Antenatally Presenting Posterior Urethral Valves (PUV) in Children

BACKGROUND

To analyze the outcome of children with posterior urethral valves who presented with antenatal hydronephrosis.

METHODS

A 10-year retrospective review of records of 70 children with posterior urethral valves.

RESULTS

The mean (SD) gestational age at diagnosis was 34 (4.48) weeks, and age at intervention was 130.5 (170.9) days. The nadir creatinine was significantly raised (<1.2 mg/dl) in children with oligohydramnios and diversion.

CONCLUSION

All boys with antenatally detected hydronephrosis need postnatal evaluation to rule out posterior urethral valves. Short term outcome is improved with postnatal treatments, and longer follow-up is needed to ensure a favourable outcome.

Posterior urethral valves: are neonatal imaging findings predictive of renal function during early childhood?

BACKGROUND

Obstructive renal dysplasia as observed on US is associated with posterior urethral valves and is regarded as predicting poor renal functional outcome.

OBJECTIVE

To investigate whether any characteristic of urinary tract imaging at birth is predictive of renal function in children with prenatally diagnosed posterior urethral valves.

MATERIALS AND METHODS

We reviewed clinical data including renal function (at birth and up to 3 years of age) and clinical outcome (urinary infection, dialysis, renal transplantation). Imaging data included US (dilatation of the urinary tract, renal cortical echogenicity, signs of cystic dysplasia, urinoma) and cystourethrography findings (vesicoureteral reflux, bladder anomalies, presence of valves) from imaging performed directly after birth.

RESULTS

We retrospectively studied 30 children. Three of the 30 (10%) were in renal failure by the age of 3 years. Twelve of 14 (85%) children with parenchymal anomalies (cortical hyperechogenicity or cystic changes) and 8/9 (89%) children with bilateral high-grade reflux had normal renal function at age 3 years. One child without cystic dysplasia or reflux had abnormal renal function from birth. None of the six children with urinoma developed renal failure by the age of 3 years.

CONCLUSION

Presence of cortical hyperechogenicity, cystic changes or bilateral reflux cannot be considered prognostic of renal failure by the age of 3 years.

Lower urinary tract development and disease

Congenital anomalies of the lower urinary tract (CALUT) are a family of birth defects of the ureter, the bladder, and the urethra. CALUT includes ureteral anomaliesc such as congenital abnormalities of the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), and birth defects of the bladder and the urethra such as bladder-exstrophy-epispadias complex (BEEC), prune belly syndrome (PBS), and posterior urethral valves (PUVs). CALUT is one of the most common birth defects and is often associated with antenatal hydronephrosis, vesicoureteral reflux (VUR), urinary tract obstruction, urinary tract infections (UTI), chronic kidney disease, and renal failure in children. Here, we discuss the current genetic and molecular knowledge about lower urinary tract development and genetic basis of CALUT in both human and mouse models. We provide an overview of the developmental processes leading to the formation of the ureter, the bladder, and the urethra, and different genes and signaling pathways controlling these developmental processes. Human genetic disorders that affect the ureter, the bladder and the urethra and associated gene mutations are also presented. As we are entering the postgenomic era of personalized medicine, information in this article may provide useful interpretation for the genetic and genomic test results collected from patients with lower urinary tract birth defects. With evidence-based interpretations, clinicians may provide more effective personalized therapies to patients and genetic counseling for their families.

Posterior urethral valves: creatinine velocity, a new early predictor of renal insufficiency

AIM

Antenatal screening has led to early detection of posterior urethral valves (PUV). However, despite early intervention, a proportion of children will develop chronic renal insufficiency. We studied the trend of serum creatinine following urinary tract decompression during the neonatal period in infants as a possible predictor of chronic renal insufficiency.

METHODS

Patients treated by endoscopic resection of posterior urethral valves between 1993 and 2004 were identified. From these, infants treated within the first 30 days of life were identified. Serum creatinine values taken within the first 5 days following initial drainage were recorded. A creatinine velocity for each patient was calculated by linear regression analysis. Creatinine was considered rising if velocity was >3 μmol/L/day, or falling if velocity was <-3 μmol/L/day. Chronic renal insufficiency was defined as CKD2 or higher.

RESULTS

Sixty-four neonates had decompression of the urinary tract. Of these, 16 had rising creatinine despite drainage, 10 had a plateau in creatinine level, and 36 had falling creatinine following drainage. Insufficient data were available in two to calculate creatinine velocity. Progression to renal insufficiency was significantly higher in patients with an initial rise in creatinine (62.5%) than in those with plateau creatinine (40%) or falling creatinine (8.6%) (P ≤ 0.0005 by Fisher exact test). Mean follow-up was 9.2 years.

CONCLUSIONS

Rising creatinine, even transiently, following urinary tract drainage in neonates with posterior urethral valves is significant and is a new and important indicator of long-term prognosis.

Endoscopic treatment of vesicoureteral reflux in children with posterior urethral valves

PURPOSE

We reviewed the clinical outcome of endoscopic injection therapy in children with vesicoureteral reflux persisting after posterior urethral valve ablation.

METHODS

We retrospectively reviewed the charts of 16 patients with posterior urethral valves who have undergone endoscopic injection to correct persistent reflux after successful relief of urethral obstruction. Breakthrough urinary tract infections, persistent high-grade reflux and failed ureteroneocystostomy were the indications of endoscopic antireflux surgery.

RESULTS

Reflux was grade I in 1, grade II in 3, grade III in 11 and grade IV in 4 ureters. Mean age at injection was 6.9 ± 3.8 years and the mean interval from initial intervention to injection was 4.3 ± 2.4 years. Injected material was dextranomer/hyaluronic acid in the majority (87.5 %) of cases. Reflux was resolved or downgraded in 12 ureters (63.1 %) after a single injection. All failed cases had urodynamically documented bladder dysfunction.

CONCLUSION

More than half of the patients with vesicoureteral reflux, persisting after initial valve ablation, showed complete resolution or significant downgrading in their reflux grade after endoscopic injection. Given the technical difficulties and potential complications of open surgical reimplantation in valve patients, endoscopic subureteral injection can be considered as an effective alternative to cure persistent vesicoureteral reflux.

Neonatal ascites and oligohydramnios: the role of kidney

Posterior urethral valve pathologies are the most frequent childhood obstructive uropathy reported, and we infer their presence on diagnosing foetal ascites and oligohydramnios. Early action is vital to determine the long-term development and the degree of impairment of renal function. We report a newborn male 34 weeks of gestation with a prenatal diagnosis of foetal ascites, fluid on the loose in renal fossa and oligohydramnios. Subsequent studies have shown the presence of posterior urethral valves with associated significant vesicoureteral reflux. There was no secondary renal damage. Intrauterine decompression of the urinary tract seems to have exerted a protective role against kidney damage. This finding supports the role of foetal decompression surgery in early and severely obstructive forms to improve the prognosis of renal function in the long term.

Posterior urethral valves: long-term outcome

Posterior urethral valves represent the most common cause of bladder outlet obstruction in infancy that impairs renal and bladder function. Long-term outcome of patients with previous PUV is evaluated. Patients over 18 years of age, treated from 1982 to 1995 before the age of 3 years were considered. Previous surgery, renal function, bladder activity, urinary incontinence, and fertility/sexual activity were evaluated. Clinical interview, creatinine clearance, uroflowmetry with ultrasound post-void urine residue, and self-administered questionnaire were recorded. Out of 45 identified records, 24 patients (53.3%) accepted to be enrolled (age 18-34 years, mean 23 years). The mean follow-up was 19.5 years (16-30 years). Out of the 21 excluded patients, 20 did not reply to the clinical interview and 1 died at age of 6 years. All the 24 patients had early endoscopic section of PUV; nine also received transient ureterocutaneostomy or vesicostomy. Ureteroneocystostomy was performed in five patients and ureterocystoplasty with unilateral nephrectomy in two. At follow-up chronic renal failure was detected in 13 patients (54.1%) and 9 (37.5%) had arterial hypertension. End-stage renal disease developed in five patients (20.8%): three had successful renal transplantation and two were in dialysis. Lower urinary tract symptoms were present in seven patients (29.1%). No significant fertility deficit and sexual dysfunction were observed in 23 patients, while 1 patient was azoospermic. No paternity was reported so far. Long-term outcome of patients with previously treated PUV is mandatory. Kidney, bladder, and sexual functions should be monitored till adulthood to verify any modified behaviour.

Current perspectives on congenital obstructive nephropathy

Congenital obstructive nephropathy is the leading cause of chronic renal disease in children. As a result, it represents a tremendous societal burden in terms of morbidity and mortality, as well as in health care expenses of caring for children with chronic kidney disease and end-stage renal disease. The various diagnostic, prognostic, and therapeutic challenges associated with congenital obstructive nephropathy highlight the importance of developing effective experimental models for studying this disease process. In this review, we define the clinical entity that is congenital obstructive nephropathy, outline the current standards of diagnosis and care, and discuss the utilization of current experimental models designed to help clarify some of the clinical conundrums associated with this important disease.

Lower urinary tract symptoms in adults treated for posterior urethral valves in childhood: matched cohort study

PURPOSE

We compared the prevalence and bother of lower urinary tract symptoms in adults treated for posterior urethral valves in childhood and population based controls.

MATERIALS AND METHODS

Questionnaires were mailed to patients 18 years and older treated at our institution for posterior urethral valves. Of the 124 patients 68 (64.2%) participated, 18 were unavailable and 38 did not participate. Age and sex matched controls were randomly identified from a population based study (response proportion 62.4%). Danish Prostatic Symptom Score was used to assess occurrence (never/rarely/often/always) and bother (none/small/moderate/major) of 12 different lower urinary tract symptoms. Chi-square test was used for the analyses stratified by patient/control status, with the 4-point ordinal scale as the outcome.

RESULTS

Median age of 68 patients with posterior urethral valves and 272 controls (ratio 1:4) was 38.5 years (range 18 to 57). Overall, at least 1 moderate or severe lower urinary tract symptom was reported by 32.4% of patients with posterior urethral valves and 15.8% of controls (p=0.002). Mild hesitancy, weak stream, incomplete emptying and straining were reported twice as often by patients with posterior urethral valves as by controls (p<0.05). Prevalence of any urgency incontinence (14.7% vs 4.8%, p=0.014) and any stress incontinence (11.8% vs 3.0%, p=0.005) was increased at least 3-fold in patients with posterior urethral valves compared to controls. Furthermore, prevalence of bother from several lower urinary tract symptoms was increased approximately 2-fold in patients with posterior urethral valves compared to controls (p<0.05). However, most patients and controls reported no or small bother.

CONCLUSIONS

In adulthood the occurrence and bother of most lower urinary tract symptoms are increased approximately 2-fold in patients with posterior urethral valves compared to the general population. However, in this cohort of young and middle-aged men most symptoms are mild.