Functional assessment of atrial M-mode in 3rd trimester in the context of postnatal balloon atrial septostomy in fetuses with simple dextro-transposition of the great arteries

Abstract Objective This study aimed to identify new functional echocardiographic features of fetal foramen ovale (FO) to predict the need of urgent balloon atrial septostomy (BAS) in neonates with simple dextro-transposition of the great arteries (d-TGA). Method Single-center prospective study of fetuses, who had prenatal echocardiographic examination <30 days before delivery and fetal diagnosis of simple d-TGA. The subjects were divided according to the need of BAS within the first 24 h after neonatal birth and before arterial switch operation. We analyzed following parameters: FO diameter, pulmonary venous maximal velocity, new FO flap tracings index analyzed by M-mode echocardiography. Results Out of 130 fetuses, 12 patients were included. Cutoff value of FO index provided maximum sensitivity (100%) and negative predictive value (100%) and cutoff value of FO index multiplied by FO diameter provided maximum specificity (100%) and positive predictive value (100%) in fetuses with fetal d-TGA in predicting need of urgent BAS. Conclusion FO index could potentially be used to predict postnatal haemodynamic stability in fetuses with simple d-TGA. FO index multiplied by FO diameter could potentially be used to predict prenatally the need of urgent BAS following the birth.