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 <3rd centile (adjusted OR 9.17) and PV peak systolic velocity (aOR 1.03) showed the strongest association with adverse outcomes. Their combined performance yielded an AUC of 0.734, with a predictive value of 71.4% at a 20% false-positive rate. Assessed individually, the AUC was 0.650 for PV peak systolic velocity and 0.639 for estimated fetal weight. Optimal PV Doppler cutoff values were >70 cm/s when EFW was <3rd centile, and >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.