How reliably does prenatal echocardiography predict urgent balloon
atrial septostomy in fetuses with d-TGA?
Abstract
Background: Transposition of the great arteries (TGA) is a conotruncal
abnormality. It is associated with ventriculoarterial discordance with
the parallel orientation of the great arteries, in which the aorta
arises from the right ventricle to supply the systemic circulation,
while the main pulmonary artery arises from the left ventricle to supply
the pulmonary circulation. Aim: To analyze the prenatal and postnatal
outcomes of fetuses with d-TGA and to determine whether prenatal
echocardiography may predict postnatal urgent BAS. Methods: A
retrospective study of fetuses with d-TGA, for which fetal
echocardiography was performed at our tertiary hospital from January
2018 to May 2023. We assessed the appearance of the septum primum and
the foramen ovale (FO) flap in the four-chamber view as to whether the
FO had a restrictive appearance during measurement of the diameter of
the FO at its maximal angle to the attachment point. Color Doppler was
used to detect ventricular septal defects (VSD) and measure its diameter
both in the four-chamber view and when visualizing the outlets of the
great arteries in the sagittal section of the heart. Results: During the
study period, 64 fetuses were diagnosed with d-TGA, which was also
confirmed postnatally. Of these, 16 fetuses were excluded due to
additional cardiac anomalies or the inability to reach the mother. In
total, 48 cases were included in this series. In our study, the FO
diameter was significantly decreased in the urgent BAS group, compared
with the fetuses without urgent BAS (5.1 mm vs 6.3 mm, p0.05). A cut
off of 6 mm for the FO diameter (sensitivity, 73.3%; specificity,
72.2%; area under the curve [AUC], 0.764) and 3.2 mm for the VSD
diameter (sensitivity, 75%; specificity, 75%; AUC, 0.728) suggested
urgent BAS. The FO diameter and the presence of VSD were independent
variables associated with urgent BAS in fetuses with d-TGA (p0.05).
Conclusion: Prenatal echocardiography in fetuses with d-TGA provides
valuable information to estimate the need for postnatal urgent BAS that
would prevent immediate life-threatening complications.