ObjectiveTo assess the function of left ventricular outlet tract and aortic valve after arterial switch operation (ASO) for patients with transposition of the great arteries (TGA) and left ventricular outlet tract obstruction (LVOTO). MethodsFrom 2002 to 2013, 549 pediatric TGA patients received ASO in Fu Wai Hospital. Among them, 42 patients had LVOTO, including 31 males and 11 females with their median age of 12 months (range, 7 days to 96 months), median body weight of 6.5(3.5-26.0) kg and percutaneous oxygen saturation of 52%-85%. LVOTO anomalies included pulmonary valve stenosis, subaortic membrane, tunnel-like subaortic stenosis, muscular subaortic stenosis, subvalvular apparatus and combined anomalies. Different surgical procedures were performed according to respective anomalies. Echocardiographic characteristics, intraoperative findings, surgical methods, early and follow-up results were summarized. ResultsCardiopulmonary bypass time was 147-344 (193.5±73.1) minutes, mean aortic cross-clamping time was 139(109-305) minutes, mean mechanical ventilation time was 36(3-960) hours, and mean length of ICU stay was 5(1-48) days. Three patients received and later successfully weaned from extracorporeal membrane oxygenation. Two patients died postoperatively including 1 patient with multiple organ dysfunction syndrome and another patient with severe infection. One patient died during follow-up for unknown reason, and 3 patients were lost during followup. Thirty-six patients were followed up for 24 (3-116) months. During follow-up, there were 1 patient with LVOTO recurrence, 1 patient with new-onset mild aortic valve stenosis, 11 patients with new-onset mild aortic regurgitation (AR), and 2 patients with new-onset moderate AR. Median systolic left ventricular-aortic pressure gradient[4 (2-49) mm Hg] was significantly lower than preoperative value[37.2 (12.1-70.6) mm Hg] (Z=-5.153). Cardiac event-free rate was 91%±5% at 1 year and 78%±8% at 5 years after discharge. ConclusionFor TGA patients with LVOTO, ASO can produce satisfactory mid-and long-term results if proper surgical indications and strategies are chosen according to different severity of LVOTO which can be evaluated by anatomic features of TGA and systolic left ventricular-aortic pressure gradient.