Complete transposition of the great arteries with intact ventricular septum and left ventricular outflow tract obstruction. Surgical management and anatomic considerations.

Surgical management of patients with complete transposition and intact ventricular septum may become difficult in the presence of left ventricular outflow tract obstruction. A Mustard operation and direct resection of the obstruction through the pulmonary artery has been the treatment of choice for this combination. Our study of the structure of the left ventricular outflow tract in four specimens with the anatomic findings of complete transposition, intact ventricular septum, and subpulmonary stenosis suggests that direct resection of the stenosis through the pulmonary artery can seldom be adequate without major risk of damaging either the mitral valve or the conduction tissue. An alternative procedure, namely, a combined Mustard operation and insertion of an external conduit from the left ventricle to the main pulmonary artery, has been employed in the management of six patients with this combination of lesions. One early and one late death occurred. Postoperative cardiac catheterization performed in all of the survivors before discharge from the hospital showed good relief of the stenosis and no significant gradient across the conduit.