Growth of the neopulmonary valve annulus after arterial switch operation in transposition of the great arteries

Background It is known that supravalvular pulmonary artery stenosis can occur in patients with d-transposition of the great arteries (TGA) after arterial switch operation (ASO). However, little is known about the growth of the neopulmonary valve annulus after the ASO. This study investigated the growth potential of the neopulmonary (old aortic) valve annulus. Methods and Results Annular diameters of the old aortic and neopulmonary valve were measured from cineangiograms in patients who underwent cardiac catheterizations both before and >1 year after the ASO. Of 71 patients, 13 (18%) had either a small annulus (<70% of the expected normal value) or no significant growth of the neopulmonary annulus after the ASO, and 4 (6%) had a pressure gradient of >30 mm Hg across the valve. The small annulus or no growth of the neopulmonary valve was more frequent in patients with a history of pulmonary artery banding. After the ASO, the valve diameter in patients with a ventricular septal defect was 80+/-15% of normal (n=24), and the value was significantly less than in patients with an intact ventricular septum (91+/-11%, n=47). In all patients with an intact ventricular septum who underwent the one-stage ASO, the valve diameters before and after the ASO were within normal limits, and a significant increase in the pulmonary valve annulus was observed. Conclusions These data indicate that not only supravalvular pulmonary stenosis but also pulmonary valvular stenosis due to a small annulus can occur in TGA, especially in patients with a history of pulmonary artery banding and in patients with ventricular septal defect.