INTRODUCTION
PAVSD is a rare congenital cardiac defect with an incidence of 0.4:10000
live births1. It is characterized by a large
perimembranous septal defect with an overriding aorta and an atretic
pulmonary valve leading to the absence of antegrade flow from the right
ventricle to the pulmonary artery (Figure 1). The infundibulum of the
pulmonary artery (PA) is often poorly formed along with the atretic
valve. The pulmonary trunk may be severely hypoplasic; confluent or
non-confluent branches of the pulmonary arteries may present as
hypoplasic vasculature. In this case, their blood supply and size depend
on either DA or the systemic arterial collateral connections, or both
(double supply). The pulmonary trunk may completely be atretic in severe
cases. In this case, the alternate source of pulmonary blood supply is
only major aortopulmonary collateral arteries (MAPCAs). MAPCAs are the
non-regressed embryological connections between pulmonary vasculature
and the aorta or the main branches of the aorta. They usually originate
from the descending aorta and communicate with the branches of the
pulmonary or bronchial arteries. Rarely, they can arise from the
branches of the aortic arch- brachiocephalic trunk, subclavian arteries-
or even from coronary arteries2,3. The patency of DA
and the presence of MAPCAs have important impacts on postnatal
management, survival, and prognosis of the cases with PAVSD. Therefore,
a detailed and accurate description of pulmonary vasculature provides
precise counseling for the parents and directs early postnatal
management.
This study aims to investigate the accuracy of fetal echocardiography in
the vascular anatomic assessment of PAVSD. The second aim is to compare
the postnatal prognosis in different pulmonary vascularization types.