ARTERIAL SWITCH IN HEARTS WITH LEFT-VENTRICULAR OUTFLOW AND PULMONARYVALVE ABNORMALITIES

Background. Pulmonary valve and left ventricular outflow tract abnorma lities (LVOT) may not be absolute contraindications to arterial switch operation (ASO). Methods. In this study we analyze long-term outcome for 26 such transposition patients (6.3% of our ASO cohort). Median ag e 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 dys plastic valve (n = 5). The LVOT abnormalities (n = 17) included access ory atrioventricular valve/endocardial cushion tissue, fibromuscular r ing, anomalous muscle bands, and septal malalignment. patients with dy namic LVOT obstruction were excluded. The median preoperative left ven tricular 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 sta ndard technique with or without LVOT resection or pulmonary valvotomy as required. Results. There were two perioperative deaths (7.7%; 95% c onfidence interval, 0.9% to 25%), and no late deaths during 1,934 pati ent-months of follow-up time. Actuarial freedom from reoperation for n eoaortic valve or LVOT problems is 87% (+/- 7) at 130 months, represen ting two reoperations. One was performed for neoaortic insufficiency p lus 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). Conclus ions. 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 wi th normal pulmonary valves and LVOT (p > 0.05), but with a greater haz ard for reoperation (p < 0.05). Selection for ASO should be based on a natomic criteria rather than left ventricular to pulmonary artery grad ient alone, to avoid assigning these patients with transposition of th e great arteries to treatment strategies less satisfactory than ASO. ( Ann Thorac Surg 1998;66:842-8) (C) 1998 by The Society of Thoracic Sur geons.