Arterial switch in hearts with left ventricular outflow and pulmonary valve abnormalities

Pulmonary valve and left ventricular outflow tract abnormalities (LVOT) may not be absolute contraindications to arterial switch operation (ASO).

In this study we analyze long-term outcome for 26 such transposition patients (6.3% of our ASO cohort). Median age and weight were 69 days (7 to 3,631 days) and 4.5 kg (2.6 to 34 kg). Pulmonary valve abnormalities included bicuspid valve (n = 4) and dysplastic valve (n = 5). The LVOT abnormalities (n = 17) included accessory atrioventricular valve/endocardial cushion tissue, fibromuscular ring, anomalous muscle bands, and septal malalignment. Patients with dynamic LVOT obstruction were excluded. The median preoperative left ventricular to pulmonary artery peak systolic pressure gradient was 30 mm (0 to 93 mm), or 50 mm (16 to 93 mm) if patients with isolated valve abnormalities are excluded. The ASO was performed according to our standard technique with or without LVOT resection or pulmonary valvotomy as required.

There were two perioperative deaths (7.7%; 95% confidence interval, 0.9% to 25%), and no late deaths during 1,934 patient-months of follow-up time. Actuarial freedom from reoperation for neoaortic valve or LVOT problems is 87% (+/- 7) at 130 months, representing two reoperations. One was performed for neoaortic insufficiency plus LVOT obstruction, and the other for isolated LVOT obstruction. One patient currently has significant neoaortic insufficiency, and median gradient at last follow-up is 0 mm Hg (range, 0 to 35 mm Hg).

The ASO can be performed in selected patients with transposition of the great arteries and with LVOT abnormalities with early and late survival and functional status similar to that of matched patients with normal pulmonary valves and LVOT (p > 0.05), but with a greater hazard for reoperation (p < 0.05). Selection for ASO should be based on anatomic criteria rather than left ventricular to pulmonary artery gradient alone, to avoid assigning these patients with transposition of the great arteries to treatment strategies less satisfactory than ASO.