Fetal Characteristics and Perinatal Outcomes in Tetralogy of Fallot Without a Ductus Arteriosus.

Absence of the ductus arteriosus (DA) is common in tetralogy of Fallot (TOF), occurring in up to 30% of cases. Yet, the clinical course and fetal echocardiographic features are not well described, limiting prenatal counseling. This study examines the fetal echocardiographic characteristics and perinatal outcomes in children with TOF absent DA (TOF/ADA), comparing them to those with a DA (TOF/DA). Fetal echocardiograms were retrospectively reviewed in children with TOF evaluated at our center between 12/1/2014 and 11/1/2022. Those with complete atrioventricular septal defect, pulmonary atresia or absent pulmonary valve were excluded. Diagnosis of TOF and absence of the DA were postnatally confirmed. Fetal echocardiographic indices, clinical characteristics, and perinatal course were compared between groups. The primary outcome was intervention (surgical or catheter-based) in the first 30 days of life. Among 58 fetuses with TOF, 23 (40%) had ADA, and 35 (60%) had a DA. The groups were similar in gestational age, with similar Apgar scores. Four neonates required interventions for cyanosis: 2 with TOF/ADA and 2 with TOF/DA. One TOF/ADA patient died within the first year of life, from non-cardiac causes. Those with TOF/ADA had smaller third trimester main pulmonary artery (MPA) z-scores (- 2.75 vs. - 2.18, p = 0.02) and smaller neonatal pulmonary valve, MPA, and branch pulmonary artery z-scores. A genetic diagnosis was more common with ADA, specifically 22q11.2 deletion (22%, p = 0.03). While there were differences observed across groups, including smaller fetal and neonatal right ventricular outflow tract size and more diagnoses of 22q11.2 in ADA, absence of the DA was not linked to poorer clinical outcomes. This study expands our understanding of fetal echocardiographic findings and clinical trajectory in TOF/ADA, offering crucial insights for consultation and postnatal planning.