Comparison of types of pulmonary stenosis with the state of the ventricular septum in complete transposition of the great arteries

The pulmonary valve and left ventricular outflow tract of 214 hearts with d-transposition of the great arteries (d-TGA) were visually inspected (126 of 214 with intact ventricular septum and 88 of 214 with ventricular septal defect [VSD]). Pulmonary stenosis (PS), either valvular, subvalvular, or in combination, was present in 26 cases and was found to be more common in the presence of a VSD (20.5%) than intact ventricular septum (6.3%). PS occurred more commonly in the presence of a supracristal VSD than an infracristal VSD (70%, 7 of 10 vs 15%, 10 of 66). Further, infracristal or supracristal VSDs were associated with different types of pulmonary obstruction. In seven of ten cases with infracristal VSD and PS, the stenosis was caused by an anomaly of an atrioventricular valve. In six of seven cases with supracristal VSD and PS, the latter was caused by membranous encirclement of the left ventricular outflow tract.