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 TGA carries a low operative mortality. However, there is a 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 TGA and patent forearm ovale (PFO) < or = 2 mm, a birthweight <2 kg, or who died before surgery, between 1988 and 1996.
Results: We identified 12 out of 295 neonates with TGA (4.1%) with anatomy suitable for the ASO who died prior to surgery. All had TGA/intact ventricular septum (IVS) and presented with a severely restrictive PFO. In 11 of 12 cases the cause of death was attributed to the sequelae of profound hypoxemia 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 a PFO < or = 2 mm who survived to ASO had a significantly better response to PGE1 infusion (p=0.03) than nonsurvivors. The ASO was accomplished without mortality in four of nine with a 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 a 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.