VENTRICULAR-FUNCTION AFTER THE ARTERIAL SWITCH OPERATION FOR TRANSPOSITION OF THE GREAT-ARTERIES

The theoretical advantages of anatomical repair have resulted in the widespread use of the arterial switch operation for transposition of the great arteries. However, preservation of systemic ventricular performance and late functional results have not been well documented. To evaluate late postoperative ventricular function, we reviewed 53 consecutive patients undergoing arterial switch operation for transposition of the great arteries with or without a ventricular septal defect over the 8-year period from March 1985 to 1993. Forty-two patients had simple transposition of the great arteries and 11 patients had associated ventricular septal defects that were closed at operation. Mean age at operation was 1.8 months (range, 1 day to 36 months), and mean patient weight was 3.8 kg (range, 1.8 to 15.6 kg). All but 8 patients were neonates. There were six operative deaths (11.3%, 6/53) and two late deaths during a median follow-up of 23 months (range, 0.1 to 99.5 months). Actuarial survival at 8 years was 83% +/- 6%. Left ventricular outflow tract obstruction has not been identified, and 9 patients (20%, 9/45) have right ventricular outflow tract gradients exceeding 20 mm Hg, 3 of whom have required reoperation. Eighteen patients have mild neo-aortic valve regurgitation. All survivors are currently in New York Heart Association class I, and are in sinus rhythm. Systolic left ventricular function is well preserved with ejection fractions greater than 0.60 in all survivors followed up for more than 4 months (41 patients). Left ventricular end-diastolic volume index is elevated in only 1 patient, a patient who had pulmonary artery banding as a neonate. The left ventricular mass index is within the normal range in 35 patients. The arterial switch operation is associated with decreasing operative risk and excellent preservation of systemic ventricular function over the medium-term follow-up period.