The following is the summary of “Posterior urethral morphology on initial voiding cystourethrogram correlates to early renal outcomes in infants with posterior urethral valves” published in the December 2022 issue of Pediatric urology by Wu, et al.

Pediatric chronic renal failure is most commonly caused by posterior urethral valves (PUV). Infants with PUV often show significant variation in the bladder and posterior urethral deformities on their first voiding cystourethrogram (VCUG). Different kinds of malformation may have different weights when assessing the gravity of the condition. If some characteristics of VCUGs can be isolated, a quick and easy screening assessment for patients may be possible. Test the hypothesis that the creatinine nadir in the first year following ablation is correlated with morphologic characteristics on the initial VCUG.

Primary valve ablation patients in children with PUV who were monitored for more than a year were identified. Researchers measured the HW-B ratio (bladder height to width), HW-PU ratio (posterior urethral height to width), and PAUR ratio (posterior-anterior urethral height to width) on the initial diagnostic VCUG (PA-UR). Around 3 pediatric urologists evaluated the trabeculation and graded it, and they also noticed reflux. Researchers compared bladder and posterior urethral morphological characteristics between those who achieved a creatinine nadir of 0.8 or ≥0.8 mg/dL in the first year following ablation using univariate analysis with chi-square and t-tests. Using linear regression, values on the morphology test were correlated with the actual nadir of creatinine concentration. About 120 boys had their testicles removed at a mean age of 40.5 days (range, 0-342), and they were then monitored for a total of 5.9 years (±3.85). The lowest creatinine level in this group was seen in 21 patients (17.5%). There was no statistically significant difference in the mean HW-B or PA-UR between those with a creatinine nadir≥ 0.8 mg/dL or lower and those with a nadir ≥0.8 mg/dL or higher. 

There was no correlation between creatinine minimum and bladder trabeculation severity. Only HW-PU differed significantly between creatinine nadir groups for the entire cohort (P<0.001), with a notably larger ratio among those with a nadir ≥ 0.8. The HW-PU was positively correlated with the creatinine nadir by linear regression (R 2=0.097, P=0.002). If you have a creatinine nadir of 0.8 mg/dL or below and you also have bilateral reflux, you are at an increased risk for developing kidney disease (P=0.001). For the first time, researchers examine the link between initial VCUG morphological parameters and renal prognosis in individuals with PUV. In contrast to reported metrics of bladder morphology, a larger HW-PU ratio, which quantifies posterior urethral deformity, is substantially linked with a higher creatinine nadir. To some extent, high-flow urethra pressure (HW-PU) may be a surrogate for the severity of obstruction in posterior urethral valves. One’s HW-PU appears to be a useful early morphologic indicator for the renal outcome.