Prenatal diagnosis of absent pulmonary valve syndrome from first trimester onwards: novel insights into pathophysiology, associated conditions and outcome.

OBJECTIVE: To assess the spectrum of associated anomalies, intrauterine course and outcome in fetuses with absent pulmonary valve syndrome (APVS). METHODS: All cases with a prenatal diagnosis of APVS at two centers over a period of 13 years were analyzed retrospectively. APVS was diagnosed in the presence of rudimentary or dysplastic pulmonary valve leaflets with to-and-fro blood flow in the pulmonary trunk on color and pulsed-wave Doppler ultrasound. Data on demographic characteristics, presence of associated conditions, Doppler studies and pregnancy outcome were reviewed. RESULTS: During the study period, 40 cases of APVS were diagnosed prenatally. Thirty-seven (92.5%) cases were associated with tetralogy of Fallot (TOF) and three (7.5%) had an intact ventricular septum. Patency of the ductus arteriosus (DA) was found in 17/37 (45.9%) TOF cases and in all three cases with an intact ventricular septum. Mean gestational age at diagnosis was 19.7 (range, 12-34) weeks with 10 (25.0%) cases (all with TOF) diagnosed in the first trimester. TOF was an isolated finding in 15 (37.5%) cases. Chromosomal anomalies, cardiac defects and extracardiac anomalies were present in 18 (45.0%), four (10.0%) and three (7.5%) cases, respectively. Among the 40 cases, there were 19 (47.5%) terminations of pregnancy, six (15.0%) intrauterine deaths, four (10.0%) neonatal deaths and 11 (27.5%) survivors. Patency of the DA, reversed flow during atrial contraction in the ductus venosus, umbilical artery or fetal middle cerebral artery, and hydrops/increased nuchal translucency thickness were significantly associated with non-survival. All 10 cases diagnosed in the first trimester had a patent DA and abnormal Doppler parameters, eight had hydrops and/or increased nuchal translucency, six were associated with trisomy 13 or 18 and none survived. CONCLUSION: APVS diagnosed in the first trimester is significantly associated with TOF, patency of the DA, abnormal Doppler parameters, lethal trisomies and intrauterine mortality. Cases of APVS with isolated TOF and agenesis of the DA have a better outcome than those with additional anomalies, with > 80% survival. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.