Early pulmonary homograft failure from dilatation due to distal pulmonary artery stenosis

Early progressive pulmonary homograft insufficiency developed in an 11-month-old infant after repair of truncus arteriosus because of dilatation secondary to the presence of residual distal pulmonary artery stenosis and hypoplasia. Before repair, the pulmonary artery branches were discontinuous, with the right pulmonary artery being somewhat hypoplastic and originating from the trunk, and the left pulmonary artery supplied by a modified Blalock-Taussig shunt created in the newborn period. At repair, a pulmonary homograft was used to connect the branches. Progressive cardiomegaly and oxygen dependance occurred 3 weeks postoperatively. Cardiac catheterization showed systemic right ventricular pressure, severe homograft insufficiency, and residual distal pulmonary artery stenosis and hypoplasia. On reoperation at 3 months postoperatively, the homograft annulus diameter increased from 14 mm to 16 mm. Dilatation and insufficiency probably occurred because the right ventricle and homograft distal to the obstruction functioned as a unit during systole. The problem might have been minimized with the use of aortic homograft which is thicker; or annular reinforcement with a synthetic material.