[Risk factors associated with arterial switch operation for transposition of the great arteries]

The present study was undertaken to determine the risk factors for early mortality following an arterial switch operation.

From January 1994 through October 2003, 78 pediatric patients underwent surgical repair. Simple transposition was present in 48 patients (61.5%), 29 (37.2%) had an associated ventricular septal defect, and one had a Taussig-Bing anomaly. The risk factors analyzed were: the patient's age and weight at the time of the intervention, repair of a coexisting ventricular septal defect, coronary artery anatomical pattern, duration of cardiopulmonary bypass, duration of aortic cross-clamping, and duration of circulatory arrest. All factors were evaluated for strength of association with the duration of mechanical ventilation, the length of intensive care unit stay, and mortality.

Overall, the early mortality rate was 9% (7/78). Some 14 patients (17.9%) underwent simultaneous repair of a ventricular septal defect. Patients with an intramural coronary artery (n=3, 3.8%) or a single coronary ostium (n=5, 6.4%) were the only ones who had a significant (P<.05) mortality risk, at 50% (4/8). Circulatory arrest was implemented in 53 (68%) patients. There were significant correlations between the duration of circulatory arrest and the ventilator support time (r=0.3, P<.05) and the duration of stay in the intensive care unit (r=0.3, P<.05).

The risk of early death was increased when more complex coronary artery anatomical variants were present. As the period of circulatory arrest lengthened, the mechanical ventilation time and duration of intensive care unit stay increased.