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 dilata tion secondary to the presence of residual distal pulmonary artery ste nosis and hypoplasia. Before repair, the pulmonary artery branches wer e discontinuous, with the right pulmonary artery being somewhat hypopl astic and originating from the trunk, and the left pulmonary artery su pplied by a modified Blalock-Taussig shunt created in the newborn peri od. At repair, a pulmonary homograft was used to connect the branches. Progressive cardiomegaly and oxygen dependance occurred 3 weeks posto peratively. Cardiac catheterization showed systemic right ventricular pressure, severe homograft insufficiency, and residual distal pulmonar y artery stenosis and hypoplasia. On reoperation at 3 months postopera tively, the homograft annulus diameter increased from 14 mm to 16 mm. Dilatation and insufficiency probably occurred because the right ventr icle and homograft distal to the obstruction functioned as a unit duri ng systole. The problem might have been minimized with the use of aort ic homograft which is thicker; or annular reinforcement with a synthet ic material.