PERSISTENT truncus arteriosus is one of the few congenital cardiovascular anomalies for which complete surgical repair has not yet been accomplished, but the anomaly is theoretically correctable.1 Repair requires (1) closure of the ventricular septal defect in such a fashion as to make the truncus originate exclusively from the left ventricle and therefore act as the aorta, (2) disconnection of the pulmonary artery from the truncus, and (3) creation of an outflow from the right ventricle to the pulmonary artery. Reconstruction of the pulmonary artery and the outflow tract of the right ventricle poses the most challenging surgical problem. Since increased pulmonary vascular resistance is present in such patients, elevated pulmonary arterial pressures persist at least for some time after surgery; thus, significant pulmonary regurgitation would ensue unless a "pulmonary valve" was inserted at surgery. As an alternate solution to prosthetic construction of a right ventricular outflow in truncus