Objectives: Predicting whether balloon atrial septostomy (BAS) will be necessary after birth for fetuses with d-transposition of the great arteries (d-TGA) remains challenging. We sought to determine whether measurements obtained during fetal maternal hyperoxygenation (MH) testing can improve our ability to predict need for postnatal BAS.
Methods: Forty-one mothers carrying fetuses with d-TGA with either intact ventricular septum or small ventricular septal defect measuring <3mm underwent MH testing between 33-38 weeks gestation. Patent foramen ovale (PFO) size, measured by 2D and color Doppler, patent ductus arteriosus (PDA) shunting (all antegrade versus bidirectional) was assessed in room air (RA) and during MH, blinded to postnatal outcome. BAS status and timing were recorded.
Results: Postnatally, 23 neonates underwent BAS while 18 did not, and 14 subjects underwent emergent BAS within 3 hours of life. By univariate analysis, PFO size measured both in RA and MH and all antegrade shunting in the PDA during MH predicted BAS. During MH testing, median PFO size by 2D measured 2.5mm (interquartile range, IQR, 2-3mm) in fetuses who underwent emergent BAS versus 4.1mm (IQR 3.4-5mm) in fetuses who did not undergo BAS (p<0.001). By cutpoint analysis, PFO size during MH testing ≤ 3.2mm predicted need for emergent BAS with sensitivity 93% and specificity 78%.
Conclusions: In d-TGA, measurement of PFO size and direction of PDA shunting during MH testing improves our ability to predict need for BAS postnatally, although additional study is needed. We propose incorporating third trimester MH testing when planning deliveries of d-TGA fetuses. This article is protected by copyright. All rights reserved.
Keywords: Congenital Heart Disease; Fetal Echocardiography; Maternal Hyperoxygenation.
This article is protected by copyright. All rights reserved.