Prenatal Predictors of Early Intervention in Simple Tetralogy of Fallot: A Retrospective Multi-Centre Study

Abstract

OBJECTIVE: Prenatal predictors of early postnatal intervention in tetralogy of Fallot (ToF) remain uncertain. This study aimed to identify prenatal cardiac and non-cardiac predictors of disease severity associated with early intervention in ToF. METHODS: This retrospective cohort study included prenatally diagnosed infants with simple ToF who underwent cardiac surgery or catheter intervention in their first year in Aotearoa New Zealand and Australia 2010-2019. Fetal echocardiography measurements from 28 to 32 weeks of gestation and prenatally diagnosed genetic and extracardiac structural anomalies were recorded. Comparison was made between infants undergoing early (≤ 30 days) and later intervention. RESULTS: Of 253 infants, 33 (13%) underwent an early intervention. Infants requiring early intervention had lower pulmonary valve (PV) Z-scores (-4.7 ± 2.2 vs. -2.6 ± 1.6; p < 0.0001) or abnormal ductus arteriosus (DA) flow (14/30 (47%) versus 20/158 (13%), p < 0.001). A PV Z-score ≤ -3.5 or abnormal flow in the DA strongly predicted the timing of intervention (sensitivity 79%, specificity 70%, AUC 0.81). There was no association between the presence of a genetic or extracardiac anomaly and the timing of cardiac intervention. CONCLUSION: Early intervention in ToF can be predicted from fetal echocardiogram measurements, including a PV Z-score ≤ -3.5 or abnormal DA flow at 28-32 weeks gestation. These findings have implications for prenatal counselling and planning of prenatal obstetric care.