Evolution of risk factors influencing early mortality of the arterial switch operation

OBJECTIVES The present study was undertaken to determine the independent ri sk factors for early mortality in the current era after arterial switch ope ration (ASO). BACKGROUND Prior reports on factors affecting outcome of the ASO demonstrat ed that abnormal coronary arterial patterns were associated with increased risk of early mortality. As diagnostic, surgical and perioperative manageme nt techniques continue to evolve, the risk factors for the ASO may have cha nged, METHODS All patients who underwent the ASO at Children's Hospital, Boston b etween January 1, 1992 and December 31, 1996 were included. Hospital charts , echocardiographic and cardiac catheterizatian data and operative reports of all patients were revievved. Demographics and preoperative, intraoperati ve and postoperative variables were recorded. RESULTS Of the 223 patients included in the study (median age at ASO = 6 da ys and median weight = 3.5 kg), 26 patients had aortic arch obstruction or interruption, 12 had Taussig-Bing anomaly, 12 had multiple ventricular sept al defects, 8 had right ventricular hypoplasia and 6 were premature. There were 16 early deaths (7%), with 3 deaths in the 109 patients considered "lo w risk" (2.7%. Coronary artery pattern was not associated with an increased risk of death. Compared with usual coronary anatomy pattern, however, inve rted coronary patterns and single right coronary patterns were associated w ith increased incidence of delayed sternal closure (p 0.003) and longer dur ation of mechanical ventilation fp 0.008). In a multivariate logistic regre ssion model using only preoperative variables, aortic arch repair at a sepa rate procedure before ASO and smaller birth weight were independent predict ors of early mortality In a second model that included both pre- and intrao perative variables, circulatory arrest time and right ventricular hypoplasi a were independent predictors of early death. CONCLUSIONS The ASO can be performed in the current era without excess earl y mortality related to uncommon coronary artery patterns. Aortic arch repai r before ASO, right ventricular hypoplasia, lower birth weight and longer i ntraoperative support continue to be independent risk factors for early mor tality after the ASO. by the American College of Cardiology.