Midterm follow-up of arterial switch operation for transposition of the great arteries with intact ventricular septum and left-ventricular outflow tract obstruction

Objective: We report the mid-term follow-up of patients, who underwent arterial switch operation (ASO) for transposition of the great arteries (TGA) with intact ventricular septum and left-ventricular outflow tract obstruction (LVOTO) over a 10-year period from 2000 to 2009. Methods: Thirteen TGA patients (3.9% of our ASO cohort) with intact ventricular septum and LVOTO underwent ASO. LVOTO was defined as pulmonary valve z-score ≤ −2.0 (n = 3) or peak LVOT gradient ≥40 mmHg with (n = 7) or without (n = 3) anatomic subvalvar stenosis on echocardiography. Median age and weight were 14 days (range, 7–130 days) and 3.2 kg (range, 2.1–4.6 kg). The LVOT abnormalities included fibromuscular narrowing (n = 5) and atrioventricular valve-related findings (n = 5). LVOT clearance was achieved by resection of accessory mitral tissue (n = 2) only. Results: Follow-up was 100% complete. There were no early or late deaths. Freedom from re-operation for neo-aortic valve regurgitation and/or LVOTO was 100% at a median follow-up of 38 months (range, 6–115 months). All patients had functional status appropriate for their age. Three patients had mild aortic regurgitation. The median Doppler estimated LVOT systolic gradient was 12 mmHg (range, 0–18 mmHg) for the entire cohort at the latest follow-up. Conclusions: Mid-term outcomes of ASO for a highly selected group of patients with pulmonary valve annulus z-score ≤ −2.0 ≥ −0.4, resectable organic LVOTO, and dynamic peak LVOT gradient ≥40 mmHg remain satisfactory, with a need for long-term follow-up.