Truncus Arteriosus

Truncus arteriosus is a rare cyanotic congenital heart disease caused by failure of the embryonic truncus arteriosus to septate into the aorta and pulmonary artery. A single large vessel arising from both ventricles supplies the systemic, pulmonary and coronary circulations together.

A large ventricular septal defect is invariably present, and the truncal valve is often dysplastic. As pulmonary vascular resistance falls in the newborn period, pulmonary blood flow increases and heart failure and progressive pulmonary hypertension develop. It is frequently associated with DiGeorge syndrome.

Diagnosis is by echocardiography. Treatment is surgical repair in the first weeks of life: the truncal root is separated from the ventricles, the pulmonary arteries are detached, and a valved conduit is placed from the right ventricle to the pulmonary artery.