Survival, kidney function, and complications in the first year of life following intrauterine shunting for first-trimester fetal megacystis (IUS1st): analysis of a prospective observational cohort.

Abstract

Congenital lower urinary tract obstruction is a major cause of chronic kidney disease in children. Severe first-trimester megacystis larger than 15 mm is almost invariably associated with poor outcome. Second-trimester vesicoamniotic shunting does not substantially improve survival or kidney function, but evidence from animal models suggests that earlier urinary tract decompression might preserve kidney function. Since 2014, the Somatex shunt has enabled first-trimester vesicoamniotic shunting, with encouraging outcomes. We aimed to prospectively describe survival, kidney function, and morbidity in infants up to 1 year after first-trimester vesicoamniotic shunting with the Somatex shunt. We conducted a descriptive analysis of a prospective cohort at the prenatal medicine centres of University Hospital Cologne and University Hospital Bonn (Germany). Singleton pregnancies were eligible if fetal megacystis with a longitudinal bladder diameter greater than 15 mm was diagnosed between gestational ages 11⁺⁰ weeks and 13⁺⁶ weeks and vesicoamniotic shunting with the Somatex shunt was done no later than gestational age 14⁺⁶ weeks. Counselling was provided by a multidisciplinary team before the procedure was done. Prenatal (ultrasonography) and postnatal (care provided according to clinical need) follow-up was provided at the study centres or local hospitals. The primary outcome was perinatal survival (survival to 7 completed days of life). Secondary outcomes were prenatal and 1-year postnatal mortality and morbidity (including kidney function assessed by nadir serum creatinine within the first year of life), recorded from clinical reports and hospital documentation according to predefined criteria. Fisher's exact test was applied to selected categorical comparisons, including differences in prenatal complication rates between surviving and non-surviving infants. The study was registered with the German Clinical Trials Register (DRKS00017779). Between June 24, 2019, and Jan 23, 2024, 40 fetuses underwent vesicoamniotic shunting at a median gestational age of 14⁺⁰ weeks (IQR 13⁺³-14⁺³). 30 infants (75%) were born alive at a median gestational age of 38⁺¹ weeks (IQR 37⁺⁴-39⁺⁰). Perinatal survival was 73% (29 of 40), and survival at age 1 year was 68% (27 of 40). One infant died during neonatal palliative care and two died during the neonatal or early infantile period. Vesicoamniotic shunting-related complications (prenatal and postanatal) occurred in 22 (55%) of 40 pregnant woman-child pairs. Three (8%) complications were associated with or resulted in prenatal death, including two cases of premature prelabour rupture of membranes and one intrauterine death. Of the 27 first year survivors, 26 (96%) did not require dialysis and had a median nadir serum creatinine of 0·21 mg/dL (IQR 0·18-0·33). In this prospective observational cohort, first-trimester vesicoamniotic shunting was technically feasible and associated with survival and predominantly normal or mildly impaired kidney function in the first year of life in a population historically characterised by poor prognosis. University of Cologne.