Fetal Ventricular Longitudinal Strain Does Not Predict Neonatal Hypoxemia in D-Transposition of the Great Arteries: A Prospective Multi-Center Study by the Fetal Heart Society Research Collaborative

Abstract Introduction : Neonates with transposition of the great arteries (TGA) and intact ventricular septum (IVS) can develop life-threatening hypoxemia after birth. There are no known reliable fetal echocardiographic markers of postnatal hypoxemia. Using a large, multi-center prospectively recruited cohort, we analyzed fetal ventricular strain and its association with postnatal hypoxemia. Material and Methods: Eighteen centers enrolled maternal-fetal dyads. Fetal ventricular longitudinal strain and strain rate measurements were obtained. The primary outcome measure was preoperative neonatal hypoxemia. The secondary outcome measure was reported need for balloon atrial septostomy (BAS). Intra- and inter-rater reliability was assessed. Fetal longitudinal strain was compared to normative data from a previously published study evaluating strain in fetuses without congenital heart disease. Results : Longitudinal strain was performed on 79 fetuses with TGA/IVS. Of those, 29 (37%) developed postnatal hypoxemia. A BAS was performed in 45 (57%). There was no statistically significant difference in fetal longitudinal strain between those with postnatal hypoxemia and those without. Similarly, fetal longitudinal strain did not differ among those who received a BAS and those who did not. Among fetuses with TGA/IVS, while right and left ventricular longitudinal strain was similar, right ventricular free wall strain was significantly higher than left ventricular longitudinal strain. Compared to the previously published normative data, longitudinal strain for both ventricles were significantly higher in fetuses with TGA/IVS. Conclusion : This prospective multi-center study identified no association between fetal longitudinal strain and postnatal hypoxemia or need for BAS in neonates with TGA/IVS, highlighting the importance of delivery planning for all fetuses with TGA to include preparations for BAS.