The arterial switch operation. An eight-year experience.

Sixty-six patients (23 neonates with transposition of the great arteries and intact ventricular septum, 33 infants and children with transposition and a large ventricular septal defect, and 10 with double-outlet right ventricle with a subpulmonary ventricular septal defect have received an arterial switch repair since 1977. Eight (one with transposition and intact ventricular septum, six with transposition and ventricular septal defect, and one with double-outlet right ventricle with subpulmonary ventricular septal defect) died in the hospital. All other patients have had follow-up as of June, 1985. Including the hospital deaths, the 11 month actuarial survival rate for the entire group was 81%, and no deaths have occurred among the 33 patients alive at that time and traced as long as 8 years. The hazard function for death has only a single early phase, and its 70% confidence limits overlap the hazard function of a matched general population by 12 months after the operation. Incremental risk factors for death included low birth weight (but not weight or age at operation), transposition of the great arteries with large ventricular septal defect, double-outlet right ventricle with subpulmonary ventricular septal defect, and presence of a patent ductus arteriosus. Coronary artery morphology and position of the great arteries were not risk factors. Long aortic cross-clamp time was possibly (p = 0.11) a risk factor. Early date of operation was a risk factor (p = 0.004); thus, predicted 1 year survival rate, including hospital deaths, after the arterial switch operation in 1985 is 99.9% (70% confidence limits 99.0%-100%) for neonates with transposition and intact ventricular septum and 99.7% (98.4%-99.9%) for those with transposition and a large ventricular septal defect or double-outlet right ventricle. The late functional status was excellent, and the rhythm was sinus in 96% of the 55 surviving patients. A formal comparison with the results of the atrial switch repair indicates that the arterial switch repair is superior.