Prenatal sonography of the foramen ovale predicts urgent balloon atrial septostomy in neonates with complete transposition of the great arteries

BACKGROUND: Hypoxia caused by inadequate intracardiac mixing owing to a restrictive foramen ovale is a potentially life-threatening complication in neonates with dextro-transposition of the great arteries. An urgent balloon atrial septostomy is a procedure of choice in such cases, but dependent on the availability of a 24-hour interventional cardiology facility. The prenatal identification of predictors for an urgent balloon atrial septostomy at birth would help in optimizing the management of these neonates, minimizing the risk of hypoxic damage. OBJECTIVE: This study aimed to predict with prenatal echocardiography the need of urgent balloon atrial septostomy in neonates with dextro-transposition of the great arteries. STUDY DESIGN: This was a retrospective cohort study of patients with a prenatal diagnosis of transposition of the great arteries that were delivered in our center between 2010 and 2019, for whom fetal ultrasound echocardiograms obtained at less than 3 weeks before delivery were available. The following parameters were systematically obtained at fetal echocardiography: size and appearance of the foramen ovale, septum primum excursion (foramen ovale flap angle at the maximal excursion), diameters of the atria, and size of the ductus arteriosus. Balloon atrial septostomy was defined as urgent if performed within 12 hours from birth in neonates with restrictive foramen ovale. Neonatal follow-up was obtained through medical records analysis. RESULTS: From November 2007 to April 2019, 160 fetuses with complete transposition of the great arteries were referred to our echocardiography laboratory and 60 of these were included in the analysis; 27 underwent urgent balloon atrial septostomy, 11 elective balloon atrial septostomy, and 22 no balloon atrial septostomy. The size of the foramen ovale was the best predictor of an urgent balloon atrial septostomy. A measurement of >6.5 mm had a sensitivity of 100% and a false positive rate of 45%. CONCLUSION: Fetal echocardiography predicts the need of an urgent balloon atrial septostomy in fetuses with dextro-transposition of the great arteries although with a limited precision. In our experience, a measurement of the foramen ovale within 3 weeks of delivery had the greatest accuracy.