Short-term postnatal renal outcome after vesico-amniotic shunting in boys with posterior urethral valves diagnosed prenatally

Introduction
The most common interventions in lower urinary tract obstruction are vesico-amniotic shunting (VAS) and serial amnioinfusions; however, their outcome remains uncertain. The aim of the study was to assess the kidney function as well as clinical complications in boys at the age of 6 months with posterior urethral valves (PUV), who underwent prenatal VAS and survived the neonatal period.

Material and methods
The study group consisted of 14 boys and the mean time of the VAS procedure was 22 weeks of gestational age (GA). Children were born in 34 GA (29–39) with average birth weight of 2860 g. Four fetuses needed amnioinfusion. In the study we assessed physical development, prevalence and aetiology of urinary tract infections (UTIs), number of hospitalizations, estimated glomerular filtration rate, presence of hypertension, albuminuria, proteinuria and acidosis.

Results
Average body weight at 6 months of life was 7.2 kg. 86% of children had at least one UTI; the same percentage were given antibacterial prophylaxis. 36% underwent urinary diversion. Median number of hospitalizations was 4. One patient required chronic renal replacement therapy, and one needed a short course of peritoneal dialysis. Median serum creatinine level was 0.65 mg/dl with estimated glomerular filtration rate (eGFR) 50.6 ml/min/1.73 m2. Average serum cystatin C level was 1.50 mg/l with eGFR 48.5 ml/min/1.73 m2. 43% developed acidosis. 71% had elevated albuminuria with a median urine albumin-to-creatinine ratio of 581.64 mg/g. 28.5% had overt proteinuria.

Conclusions
Growth at the age of 6 month of infants with PUV after prenatal VAS was barely satisfactory. More than half had impaired kidney function, but the need for renal replacement therapy was uncommon.