CLINICAL OUTCOMES AFTER THE ARTERIAL SWITCH OPERATION FOR TRANSPOSITION - PATIENT, SUPPORT, PROCEDURAL, AND INSTITUTIONAL RISK-FACTORS

Background. As the probability increases that the arterial switch operation is optimal treatment for transposition, detailed information about outcomes and the circumstances in which they are suboptimal becomes important. Methods and Results. A multi-institutional prospective study with annual detailed follow-up included 513 neonates with simple transposition or transposition and ventricular septal defect entering for diagnosis and treatment at <15 days of age and undergoing an arterial switch repair. The 1-month and 1- and 5-year survivals were 84%, 82%, and 82%, respectively. The hazard function for death had a rapidly declining single phase that approached zero by 12 months after surgery. Among the eight patients who died greater-than-or-equal-to 3 months after the operation, four had severe ventricular dysfunction, probably related to imperfect coronary arterial transfer. Coexisting single ventricular septal defect was not a risk factor for death. Origin of the left main coronary artery or only the left anterior descending or the circumflex artery from the right posterior sinus (sinus 2) was a risk factor that was even stronger when an intramural course was present; multiplicity of ventricular septal defects was a risk factor. Longer global myocardial ischemic time and total circulatory arrest time were risk factors. Certain institutions were shown to be risk factors for death; the results in some improved with increasing experience, in some they did not, and in some they worsened. Conclusions. Good early and intermediate-term clinical outcomes can be obtained in neonates with simple transposition and transposition and ventricular septal defect by use of the arterial switch operation. Certain coronary artery patterns and certain institutions lessen the goodness of outcome.