Prenatal Features of a Truncus Arteriosus With Pulmonary Atresia and Pulmonary Circulation Derived From the Ductus Arteriosus

Abstract

truncus arteriosus is a solitary great artery arising from the base of the heart and supplying the systemic, pulmonary, and coronary circulation. A truncus arteriosus is a rare cardiac defect, accounting for less than 1% of structural heart defects.1 The single great artery usually arises above a malalignment ventricular septal defect (VSD) and straddles the ventricular septum. There is variability in the origins of the pulmonary branch and whether the aortic arch is interrupted. Van Praagh and Van Praagh1 suggested classifying trunci arteriosi with VSD into 4 types. In type I, a main pulmonary artery arises from the truncal root and bifurcates into the branch pulmonary arteries. In type II, the branch pulmonary arteries are separate from the truncal root. In type III, the left pulmonary artery is supplied by a collateral from the aortic arch and does not arise from the truncal root. In type IV, the aortic arch is interrupted. A truncus arteriosus may rarely occur without a VSD. Although prenatal diagnosis of a truncus arteriosus has been reported several times,2–4 to our knowledge, the rare variant with an atretic main pulmonary trunk and normal pulmonary circulation such as the case presented here has not been described prenatally. The objective of this report was to show abnormal fetal circulation associated with a truncus arteriosus with pulmonary atresia but with well-developed pulmonary circulation derived from retrograde flow through the ductus arteriosus.