Quantitative analysis of postoperative changes in the pulmonary vasculature of patients with complete transposition of the great arteries and pulmonary hypertension.

Postoperative changes in the medial thickness of the small pulmonary arteries and the degree of pulmonary vascular disease were estimated histometrically and histopathologically in three cases of late death after total correction of complete transposition of the great arteries with large ventricular septal defect and pulmonary hypertension. In the postoperative course of two of the three cases extreme medial hypertrophy of the small pulmonary arteries as well as severe pulmonary vascular disease were found. In the third case, the thickening of the media was mild and pulmonary vascular disease had not progressed owing to a residual ventricular septal defect. Examination of three additional cases of late death and 15 autopsy cases of complete transposition of the great arteries revealed that hypertrophy of pulmonary arterial media after radical surgery for complete transposition of the great arteries is a common phenomenon. In cases of complete transposition of the great arteries with severe pulmonary hypertension, the deveopment of marked hypertrophy of the media accompanied by pulmonary vascular disease after total correction is usually seen and seems to be the most likely cause of death in the postoperative period.