The importance of neo-aortic root geometry in the arterial switch operation with the trap-door technique in the subsequent development of aortic valve regurgitation

Abstract

Regarding neo-aortic valve regurgitation (neo-AR) after the arterial switch operation (ASO), the 'trap-door' technique was supposed to be a risk factor due to a distortion of the sinotubular junction (STJ) geometry. Here we report our results of the 'trap-door' technique with a special emphasis on root geometry including the ratio of STJ to annulus. From August 1991 to March 2010, 240 patients with transposition of the great arteries underwent the ASO and who had at least 1 year of follow-up were included in this study. The medical records were retrospectively reviewed. The median age and body weight at the time of operation were 11 (0-1213) days and 3.4 (1.30-18.75) kg, respectively. The median follow-up duration was 79 months (range 12 months-19.5 years). At the latest echocardiographic follow-up, only six patients had neo-AR greater than Grade II (6 of 240, 2.5%). We found no relationship between neo-AR greater than Grade II and perioperative factors. The actual sizes of the neo-aortic annulus, mid-sinus and STJ were observed as having increased over time. However, most z-scores of STJ at the latest echocardiography varied between -2 and 2 and, more importantly, the ratio of STJ to neo-aortic annulus was 0.93 ± 0.20, which was near normal at the latest echocardiographic follow-up. Our results showed a very low incidence of significant neo-AR, which was relatively attributable to the preserved z-score of STJ and the normal range of STJ/annulus ratio. Therefore, we propose that it is important to maintain these factors adequately during the reconstruction of the neo-aortic root in the ASO.