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.