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.