Late follow-up of neo-aortic dimensions and coronary arteries in adult patients after the arterial switch operation.

Background: After the arterial switch operation (ASO) for transposition of the great arteries (TGA), neo-aortic dilatation and coronary arterial anomalies, especially an interarterial course and acute coronary artery take-off angle, are commonly found. Long-term follow-up data after ASO is scarce. Aim of this study was to determine the prevalence of neo-aortic dilatation and coronary abnormalities, with special emphasis on acute coronary take-off angle, in adult TGA-ASO patients. Methods: In this retrospective cohort study, all adult TGA-ASO patients with ≥1 CT-angiography (CTA) at the age of ≥16 years were included. Results: Eighty-one patients, 69 % male and median age 21.0 [18.5-22.8] years, were included. At baseline, maximum neo-aortic diameter was 39.2 ± 5.3 mm; 35 (43 %) patients had neo-aortic dilatation (neo-aortic diameter of >40 mm), 22 (27 %) patients had an acute coronary take-off angle (<30°), and 5 (6 %) patients had an interarterial course of the RCA (2 %) or LCA (4 %). Neo-aortic or coronary artery re-intervention occurred in 10 (12 %) patients. All 10 patients had neo-aortic dilatation or coronary take-off angle of <30° on baseline CTA. Conclusion: This study reports a prevalence of 43 % of neo-aortic dilatation, 6 % of interarterial coronary course and 27 % for acute coronary take-off angle (<30°) at a median term of 21.0 years post ASO. All patients with a neo-aortic re-intervention or coronary artery re-intervention during follow-up had a maximum neo-aortic diameter of >40 mm or a coronary take-off angle of <30° at baseline CTA. This hypothesis generating study suggests that an active surveillance in patients with neo-aortic dilation and/or an acute angulation of < 30° post ASO might be considered and requires prospective evaluation.