Anomalous pulmonary arteries

Abstract

The anomalous origin of the pulmonary artery (also called “hemitruncus”) is a rare congenital malformation in which only one pulmonary artery branch, usually the right (opposite to the laterality of the aortic arch), originates from the posterior aspect of the ascending aorta just above the aortic sinotubular junction, without any defect between the ascending aorta and the main pulmonary artery, whereas the main pulmonary artery and the other pulmonary artery branch arise in their normal position and, therefore, are connected with the morphological right ventricle. The other main difference with persistent truncus arteriosus is the presence of two well-separated semilunar valves, aortic and pulmonary valves, and the usual absence of ventricular septal defect. Therefore, hemitruncus defines only the anomalous origin of one pulmonary artery. The anomalous pulmonary artery, most frequently the right, has unrestricted origin, and normal structure, course and distribution.