Absent ductus arteriosus in Tetralogy of Fallot: early outcomes from a matched fetal cohort study

The impact of absent ductus arteriosus in fetuses with Tetralogy of Fallot remains uncertain with concerns for the lack of prostaglandin responsiveness and compromised pulmonary blood flow. This study evaluated early postnatal outcomes in fetuses with Tetralogy of Fallot-absent ductus arteriosus compared to matched controls with a ductus arteriosus and assessed the predictive value of fetal and neonatal echocardiographic parameters for early intervention.

A retrospective matched cohort study was performed using a single-centre fetal echocardiography database (2000-2024). Fetuses with Tetralogy of Fallot-absent ductus arteriosus confirmed by neonatal echocardiography were matched 1:1 to Tetralogy of Fallot-ductus arteriosus cases by fetal pulmonary valve Z-score and gestational age. Early intervention was defined as any surgical or transcatheter procedure to augment pulmonary blood flow within six weeks of life. Comparative analyses evaluated predictors of early intervention within each cohort.

Among 253 fetuses with Tetralogy of Fallot and antegrade outflow, 27 had confirmed absent ductus arteriosus and were matched to 27 Tetralogy of Fallot-ductus arteriosus controls. Despite similar fetal pulmonary valve Z-scores, Tetralogy of Fallot-absent ductus arteriosus patients had significantly lower neonatal pulmonary valve and main pulmonary artery Z-scores and main pulmonary artery-to-aorta ratios. Early intervention occurred in 26% of Tetralogy of Fallot-absent ductus arteriosus and 41% of Tetralogy of Fallot-ductus arteriosus (p = 0.25); surgical intervention was more frequent in Tetralogy of Fallot-absent ductus arteriosus (86 vs 36%, p = 0.066). In Tetralogy of Fallot-ductus arteriosus, lower fetal and neonatal pulmonary valve/aortic valve ratios predicted early intervention. No fetal or neonatal markers were predictive in Tetralogy of Fallot-absent ductus arteriosus.

Fetal absent ductus arteriosus was not linked to higher early intervention rates in Tetralogy of Fallot, but when intervention was required, surgical palliation predominated. Conventional fetal echocardiographic predictors were not reliable in Tetralogy of Fallot-absent ductus arteriosus, complicating prenatal counselling.