FACTORS INFLUENCING EARLY AND LATE OUTCOME OF THE ARTERIAL SWITCH OPERATION FOR TRANSPOSITION OF THE GREAT-ARTERIES

Between January 1983 and January 1992, 470 patients underwent an arter ial switch operation at our institution, An intact (or virtually intac t) ventricular septum was present in 278 of 470 (59%); a ventricular s eptal defect was closed in the remaining 192, Survivals at 1 month and 1, 5, and 8 years among the 470 patients were 93%, 92%, 91%, and 91%, respectively, The hazard function for death (at any time) had a rapid ly declining single phase that approached zero by one year after the o peration. Risk factors for death included coronary artery patterns wit h a retropulmonary course of the left coronary artery (two types) and a pattern in which the right coronary artery and left anterior descend ing arose from the anterior sinus with a posterior course of the circu mflex coronary. The only procedural risk factor identified was augment ation of the aortic arch; longer duration of circulatory arrest was al so a risk factor for death. Earlier date of operation was a risk facto r for death, but only in the case of the senior surgeon. Reinterventio ns were performed to relieve right ventricular and/or pulmonary artery stenoses alone in 28 patients. The hazard function for reintervention for pulmonary artery or valve stenosis revealed an early phase that p eaked at 9 months after the operation and a constant phase for the dur ation of follow-up. Incremental risk factors for the early phase inclu ded multiple ventricular septal defects, the rapid two-stage arterial switch, and a coronary pattern with a single ostium supplying the righ t coronary and left anterior descending, with a retropulmonary course of the circumflex The need for reintervention has decreased with time. The arterial switch operation can currently be performed early in lif e with a low mortality risk (<5%) and a low incidence of reinterventio n (<10%) for supravalvular pulmonary stenosis. The analyses indicate t hat both the mortality and reintervention risks are lower in patients with less complex anatomy.