Fetal predictors of urgent balloon atrial septostomy in neonates with complete transposition

Background: In complete transposition of the great vessels, a restrictive patent foramen ovale leads to inadequate circulatory mixing and severe cyanosis. Urgent balloon atrial septostomy (BAS) improves mixing and bridges neonates to surgery. Several studies have determined risk factors in utero for poor postnatal outcomes in complete transposition of the great vessels, particularly a restrictive patent foramen ovale and ductus arteriosus. In addition to these risk factors, we studied two new features, a hypermobile septum and reverse diastolic patent ductus arteriosus shunt, to determine which patients will require an urgent BAS.

Methods: We reviewed all 26 fetuses from 2001 to 2010 with complete transposition of the great vessels and closely examined the patent foramen ovale and septum primum for hypermobility, restriction, flat appearance, or redundancy. We defined hypermobility as a septum primum flap that oscillates between both atria. We also examined the ductus size and shunting pattern to evaluate whether these features contributed to urgent BAS.

Results: In total, 14 of 26 fetuses required urgent BAS with improved cyanosis. Nine fetuses had an urgent BAS and a hypermobile septum, and 12 fetuses had no urgent BAS or hypermobile septum. Eight fetuses had an urgent BAS and a reverse diastolic patent ductus arteriosus, and 11 fetuses had no urgent BAS or reverse diastolic patent ductus arteriosus. A hypermobile septum and reverse diastolic patent ductus arteriosus had a significant association with urgent BAS (P < .01, sensitivity = 0.64 and 0.57, specificity = 1.0 and 0.92, positive predictive value = 1.0 and 0.89, negative predictive value = 0.71 and 0.65). No fetus had a restrictive patent foramen ovale/ductus arteriosus.

Conclusion: A hypermobile septum and reverse diastolic patent ductus arteriosus are new prenatal findings to help predict the need for an urgent BAS postnatally in patients with complete transposition of the great vessels.