OP04.09: Pulmonary blood supply in pulmonary atresia with ventricular septal defect: prenatal identification of systemic to pulmonary collateral arteries

Abstract

Objective: To describe the antenatal findings of systemic to pulmonary collateral arteries (SPCA) in the setting of pulmonary atresia (PA) and ventricular septal defect (VSD) and the impact upon pregnancy management. Methods: Retrospective review of cases in tertiary fetal cardiology centre. All prenatally diagnosed cases of PA with VSD that presented between January 1997 and December 2004 were identified using hospital databases. Findings from prenatal echocardiography were compared to postnatal data, or autopsy findings in cases where pregnancy was terminated. Results: Of 4949 fetuses 29 (0.6%) had PA, 8 with an intact ventricular septum and 21 with a large VSD. Among those with a VSD, 8 had ‘tetralogy type’ anatomy with anterior deviation of the outlet septum and an overriding aorta: in 4 of these cases pulmonary blood supply was retrograde through the arterial duct and in 4 SPCA from the descending aorta were identified. In 3 of the 4 with SPCA despite absence of the arterial duct, central pulmonary arteries were identified. Pregnancy was continued in 2 cases while 2 underwent termination. In three cases the presence of SPCA was confirmed by cardiac catheterisation, post-mortem examination or postnatal echocardiography. Pregnancy was terminated in the fourth case and no post-mortem was performed. In the 2 live births we did not commence on prostaglandin E infusion. In one case, severe pulmonary stenosis rather than atresia was shown post-natally. In the remaining 13 cases with a VSD, PA was part of more complex anomalies and pulmonary blood supply was via the arterial duct in all. Conclusion: SPCA can be accurately identified prenatally with and without central pulmonary arteries. This allows precise description of pulmonary blood supply in the fetus with PA and VSD, thus helping prenatal counselling, pregnancy management and management of the newborn.