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.

OBJECTIVE: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.