Patterns of pulmonary arterial supply in patients with truncus arteriosus

Abstract

Patients with anatomic discontinuity between the heart and pulmonary arterial system are now candidates for corrective surgical procedures. Differentiation between patients with pulmonary arteries (truncus arteriosus types I, II and III, and pseudotruncus) and those without pulmonary arteries (absent sixth aortic arch, truncus arteriosus type IV) is crucial. Anatomic classification, diagnostic criteria, and indications for surgical repair are still controversial. This paper presents four cases of truncus arteriosus that were managed surgically. Three of these had variants of type I anatomy, with hypoplasia or atresia of the connection to the ascending aorta. The fourth patient had a complicated type of truncus IV anatomy. Three points are emphasized: (I) Patients with type I truncus arteriosus can present with hypoplasia or atresia of the truncus-pulmonary connection. These patients may have suitable anatomy for full physiological correction, and their condition should not be confused with the type IV anatomy. (2) Ligation of collateral arterial supply is important. (3) We hypothesize that any patient with truncus arteriosus and continuous murmur has some kind of pulmonary arterial system which is surgically accessible. Currently, we perform an exploratory operation on any such patient. If reasonably large pulmonary arteries are found at operation, physiological correction with a valved conduit is performed. If the arteries are diminutive, a systemic-to-pulmonary shunt is constructed which it is hoped will stimulate dilation of the pulmonary arterial system and allow later physiological correction. Prolonged follow-up of a larger number of these patients is necessary.