Postnatal Clinical Course in Fetuses Diagnosed with Tetralogy of Fallot and Double-Outlet Right Ventricle with Absent Ductus Arteriosus

Introduction: Absent ductus arteriosus (ADA) in fetuses with tetralogy of Fallot (TOF) and TOF-type double-outlet right ventricle (DORV) remains poorly characterized. The absence of a patent ductus arteriosus precludes prostaglandin-mediated maintenance of ductal patency and may necessitate early postnatal intervention. Methods: This retrospective study reviewed 31 consecutive fetuses diagnosed with TOF (n=23) or TOF-type DORV (n=8) between April 2018 and March 2025. Fetal echocardiographic measurements in the third trimester included pulmonary valve (PV), aortic valve (AoV), main pulmonary artery (MPA), and ascending aorta (AA) diameters. The patients were stratified according to ADA (n=14) or patent ductus arteriosus (PDA) (n=17). Postnatal outcomes, including systemic-to-pulmonary (SP) shunt necessity, timing, and rate of valve annulus preservation at definitive repair were assessed. Results: Patients with ADA demonstrated smaller fetal PV/AoV ratios (0.59±0.07 vs. 0.68±0.12; p=0.03), MPA z-scores (−2.3±0.9 vs. −1.4±0.7; p=0.008), and MPA/AA ratios (0.61±0.08 vs. 0.71±0.09; p=0.005) than in fetuses with PDA. While SP shunt rates during initial admission were similar (50% vs. 23%; p=0.20), ADA required higher cumulative SP rates before definitive repair (78% vs. 35%; p<0.01). Valve annulus preservation rates were comparable between the two groups (72% vs. 65%; p=0.85). Conclusion: ADA was associated with significantly smaller right ventricular outflow tract dimensions. Although ADA requires a more staged intervention, valve preservation rates at definitive repair are similar to those in PDA cases.