Are pressure pop-offs beneficial to the bladder in boys with posterior urethral valves?

Long-term bladder outcomes using a prescriber pattern scoring system for posterior urethral valves

BACKGROUND

Urinary drainage for posterior urethral valves can be achieved with valve ablation (VA) or diversion by vesicostomy (VES) or cutaneous ureterostomy (CU). The effect of these interventions on long-term bladder function remains debated, and voiding symptomatology after VES or CU reversal has been poorly characterized.

OBJECTIVE

The objective of this study was to examine the prevalence and scope of physician treatment patterns as a surrogate for retention or incontinence symptomatology among PUV patients undergoing primary VA or diversion by VES/CU and determine rates of progression to augmentation.

STUDY DESIGN

This is a single-institution retrospective cohort study. Retention Scores (R) were calculated 1 point for: retention behavior (double/timed void), alpha-blocker, intermittent catheterization, or overnight indwelling catheter. Incontinence Scores (I) were calculated 1 point for: incontinence behavior (double/timed void), oral medication, or botulinum toxin. Patients with R score above 3 or I score above 2 were deemed to have severe retention or incontinence symptomatology respectively. End stage bladder (ESB) was defined as need for bladder augmentation.

RESULTS

We identified 76 patients between 5 and 40 years old with median follow-up of 14.6 [5.0-40.4) years. There was no difference in the rates of severe retention or incontinence treatment pattern scoring between VA versus VES/CU (Figure). Rates of achieving R(1) status are similar between VA and VES/CU groups, though age of reaching R(1) was younger for those with VES/CU (4.8 years) compared to VA (6.6 years). There was no significant difference in rate of ESB by intervention category VA (9.4%) versus VES/CU (17.4%; p = 0.323).

DISCUSSION

Treatment of retention symptomatology was more common than treatment of incontinence symptomatology regardless of primary management, VA or VES/CU. This study also indicates that VES/CU patients were just as responsive as VA patients to conservative treatments (behavioral changes, pharmacotherapy) for any type of bladder symptomatology as the progression to treatment of severe symptomatology and ESB were similar between cohorts. In this cohort, bladder outcomes were not associated with type of urinary diversion (VA or VES/CU).

CONCLUSION

Long term bladder outcomes for valve patients demonstrated similar treatment patterns and progression to end-stage bladder regardless of diversion status. Patients went on to ESB approximately 4.4 years after diagnosis at similar rates between groups.

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, Unilateral Vesicoureteral Reflux, and Renal Dysplasia (VURD) Syndrome: Long-Term Longitudinal Evaluation of the Kidney Function

The presence of unilateral vesicoureteral reflux (VUR), and renal dysplasia associated with posterior urethral valves (PUV) (VURD syndrome) was believed to represent a pressure-released pop-off mechanism protecting kidney function. We aimed to investigate its role with respect to long-term kidney function in a cross-sectional and longitudinal analysis. We compared the iohexol glomerular filtration rate (GFR) measured at 5 (GFR5) and 10 (GFR10) years of age in children with (Group A) and without (Group B) VURD syndrome, who underwent PUV resection under 2 years of age. VURD syndrome was diagnosed in cases of unilateral loss of kidney function (<15% on nuclear medicine test) associated with ipsilateral grade IV-V VUR. VURD syndrome was diagnosed in 16 (12.8%) out of 125 patients who met the inclusion criteria. While the median GFR5 was similar in the 2 groups [Group A: 87.3 (74.7-101.2) mL/min/1.73 m2 vs. Group B: 99.6 (77-113) mL/min/1.73 m2, p-value: 0.181], the median GFR10 values were significantly lower in children with VURD syndrome [Group A: 75.7 (71.2-85.9) mL/min/1.73 m2 vs. Group B: 95.1 (81.2-114.2) mL/min/1.73 m2, p-value: 0.009]. Similar results were obtained in a longitudinal analysis of the children with GFR measurement available both at 5 and 10 years of age [GFR5 in Group A: 93.1 (76.9-103.5) mL/min/1.73 m2 vs. Group B: 97.5 (80-113) mL/min/1.73 m2, p-value: 0.460; GFR10: Group A: 71.9 (71.9-85.9) mL/min/1.73 m2 vs. Group B: 94.8 (81.5-110.6) mL/min/1.73 m2, p-value: 0.024]. In conclusion, VURD syndrome does not show a protective role in kidney function preservation. On the contrary, it seems to be associated with a deterioration of the kidney function on a long-term follow-up.

Does VURD syndrome impact voiding efficiency in posterior urethral valves?

INTRODUCTION

There is debate regarding the effect of VURD syndrome, consisting of vesicoureteral reflux (VUR) and ipsilateral kidney dysplasia, on long-term outcomes in boys with posterior urethral valve (PUV). Here, we assessed whether VURD syndrome played a "protective" role on long-term bladder outcomes and voiding efficiency in boys with PUV.

MATERIALS AND METHOD

A retrospective chart review was conducted for toilet-trained children with PUV managed at our institution between 2000 and 2022, only excluding cases without recorded uroflowmetry studies. Patients were stratified by VUR status and by the presence of VURD syndrome (high-grade VUR + ipsilateral kidney dysplasia). Outcomes included initial and final uroflowmetry parameters, and initiation of clean-intermittent catheterization (CIC).

RESULTS

We identified a total of 101 patients who met study inclusion criteria, with an overall median follow-up of 114 months (IQR 67, 169). The median age of first and last uroflowmetry was 57 months (IQR 48, 82) and 120 months (IQR 89, 160), respectively. Patients with VURD syndrome had similar flow velocity, post-void residuals, and bladder voiding efficiency to other PUV patients at last follow-up uroflowmetry. On survival analysis, patients with VURD syndrome had no significant difference in risk of requiring CIC compared to patients without pop-offs (p = 0.06).

DISCUSSION

Like more contemporary studies on pressure pop-offs, we show that this population is not at higher risk of poorer voiding and intermittent catheterization than others. VURD syndrome does not confer protection against poorer bladder function. Instead, our study suggests an independent association between kidney dysplasia and bladder outcomes which requires further attention.

CONCLUSIONS

Among boys with PUV, VURD syndrome was not associated with significantly different uroflowmetry findings or rates of CIC by last follow-up.

Evaluating the impact of pop-off mechanisms in boys with posterior urethral valves

INTRODUCTION

Posterior urethral valves are urethral leaflets that cause Lower Urinary Tract Obstruction (LUTO) in boys and are associated with congenital renal dysplasia and abnormal bladder function. They affect 1:4,000 to 1:25,000 births and can be responsible for End-Stage Renal Failure in childhood. There have been several studies on the effect of pop-off mechanisms in boys with posterior urethral valves, but results are contradictory. We aimed to assess and discuss the effect of pop-off mechanisms on renal function in a large cohort of patients.

PATIENTS AND METHOD

Boys with PUV with and without pop-off mechanisms (urinoma, VURD or giant bladder diverticula) were divided into three severity groups for renal function according to their nadir creatinine (low-risk NC < 35 μmol/L, intermediate-risk NC between 35 and 75 μmol/L, and high-risk NC > 75 μmol/L). We compared children with and children without pop-off mechanisms for mean renal function as well as patient distribution within each severity group.

RESULTS

We included 137 boys of which 39 had a pop-off mechanism. Patients had complete data for at least 5 years follow-up. Though there was no significant statistical difference in mean renal function between the pop-off and non-pop-off group, patient distribution within each severity group varied according to whether patients had a pop-off mechanism or not.

CONCLUSION

Though there was no significant difference in mean renal function between boys with and without pop-off mechanisms, it is possible that these are two different patient populations and direct comparison is not possible.

Detection of bladder trabeculation by voiding cystourethrography and sonography: observations in boys with posterior urethral valves

Background

As trabeculated bladder wall is often referred to as a sign of chronically increased intravesical pressure, we investigated whether voiding cystourethrography (VCUG) or sonography reliably predicts bladder trabeculation on later urethrocystoscopy.

Methods

A total of 76 consecutive patients (2012–2017) with cystoscopically confirmed posterior urethral valves (PUV) and pre-endoscopy VCUG were included. Sonography data were available for 68 of these patients. Radiological findings were reassessed and compared with endoscopic findings using Fisher’s exact test and Spearman’s rank assessment.

Results

VCUG showed a sensitivity of 83.3% and a specificity of 30% in predicting trabeculation on a later urethrocystoscopy, with no significant difference in determining mild or severe forms (p=0.51). Sonography proved a sensitivity of 27.6% and a specificity of 70%, with no correlation between sonographic signs and trabeculation on cystoscopy (r=0.1311). In addition, vesicoureteral reflux had no significant influence as a possible pressure pop-off mechanism on the development of trabeculation in our group.

Conclusions

While VCUG predicts bladder trabeculation in children with PUV with limited reliability, sonography mostly fails to detect trabeculation. Therefore, such findings should only be used with utmost caution in relation to clinical decision-making.