Mortality in potential arterial switch candidates with transposition of the great arteries

Objectives. We reviewed the factors contributing to or causing death before surgery in neonates with d-transposition of the great arteries (TGA) despite anatomy suitable for the arterial switch operation (ASO) to develop strategies to minimize preoperative attrition. Background. Currently the ASO for neonates with TG carries low operative mortality. However, there is paucity of information regarding the patients who die before the ASO. Strategies to ensure survival to operation are of importance to improve overall outcome. Methods. We reviewed all neonates with TG and patent forearm ovale (PFO) ≤2 mm, birthweight <2 kg, or who died before surgery, between 1988 and 1996. Results. We identified 12 out of 295 neonates with TG (4.1%) with anatomy suitable for the ASO who died prior to surgery. All had TGA/intact ventricular septum (IVS) and presented with severely restrictive PFO. In 11 of 12 cases the cause of death was attributed to the sequelae of profound hypoxemi from inadequate mixing. Contributing factors were prematurity, 41.7%; severe respiratory distress syndrome, 25%; and persistent pulmonary hypertension of the newborn (PPHN), 16.7%. All patients received prostaglandin E1 (PGE1) infusion. Urgent balloon atrial sepstostomy (BAS) was performed in 66.7% with improved oxygenation. No cases were diagnosed prenatally. In contrast, all patients with PFO ≤ 2 mm who survived to ASO had significantly better response to PGE1 infusion (p = 0.03) than nonsurvivors. The ASO was accomplished without mortality in four of nine with weight <2 kg. Conclusions. Of those neonates admitted with TGA, 4.1% died before surgery. Eleven of 12 (3.7%) died due to consequences of inadequate interatrial mixing despite PGE1 infusion. Earlier diagnosis and BAS are critically important in determining survival. Early ASO may improve survival in patients weighing <2 kg. Prenatal diagnosis with delivery in high-risk obstetrical unit with facilities for immediate BAS and supportive therapy for pulmonary hypertension and ventricular failure may be necessary to salvage this group of patients.