Prognostic value of fetal growth and prenatal functional echocardiography in tetralogy of FALLOT

INTRODUCTION: Tetralogy of Fallot (ToF) shows variability in neonatal outcomes, and identifying reliable prenatal predictors is essential for optimizing perinatal management. The aim of this study was to determine the prognostic value of feto-placental data and prenatal echocardiography in the third trimester in ToF and to compare these findings with a matched control population. MATERIAL AND METHODS: Multicenter prospective cohort study (2011-2023) at two referral centers (BCNatal and University Hospital of Gießen and Marburg). The cohort included 63 fetuses with isolated ToF and 66 healthy controls. All fetuses underwent a third trimester ultrasound and comprehensive echocardiography with 2D speckle tracking. Severe small-for-gestational age (SGA) was defined as estimated fetal weight (EFW) below the third percentile. Adverse composite outcomes were defined as the need for prostaglandin infusion, surgery or ductal stenting, corrective surgery before 3 months, and/or neonatal intensive care unit stay ≥7 days. The association of feto-placental and cardiac data with adverse composite outcome was evaluated. RESULTS: Compared with controls, ToF fetuses showed higher rates of severe SGA (19% vs. 0%, p < 0.001). Cardiac findings showed mild biventricular concentric hypertrophy (relative wall thickness ToF 0.7 [0.5-0.9] vs. controls 0.5 [0.5-0.6], p = 0.001), and reduced deformation (right and left ventricular global longitudinal strain: ToF -17.3% ± 3.8 vs. controls -19.3% ± 3.1, p = 0.001; ToF -18.0% ± 3.8 vs. controls -20.9% ± 3.45, p < 0.001), regardless of placental dysfunction. The adverse composite outcome occurred in 29.3% of ToF cases with pulmonary stenosis. Within this group, EFW 70 cm/s when EFW was 144 cm/s when EFW was above the 3rd centile. CONCLUSIONS: Combining EFW with PV artery Doppler may allow identification of a high-risk subgroup of ToF-PS fetuses who may benefit from closer prenatal monitoring and prompt neonatal care.