Predictors of Outcome of Arterial Switch Operation for Complex D-Transposition

Abstract

Overall mortality and reoperation risk for the arterial switch operation (ASO) for D-transposition of the great arteries (D-TGA) is low. D-TGA with ventricular septal defect (VSD) and aortic arch obstruction (AAO) is a higher risk subgroup in which we sought risk factors for mortality and reoperation after ASO. Echocardiograms of 74 patients who underwent ASO, VSD, and arch repair for D-TGA, VSD and AAO were reviewed; the reoperation analysis considered the 65 survivors. Pre-ASO clinical and anatomic characteristics were compared between survivors and nonsurvivors; patients who required (R) and did not require (NR) reoperation. Distal transverse aortic arch (TrAo) z score equal to -2.5 or less, triscuspid valve z score less than 0, repaired muscular VSD, and circulatory arrest time were significant predictors of mortality. When stratified for circulatory arrest time below 60 minutes, small distal transverse aortic arch and tricuspid valve remained significant predictors of mortality. Mean aortic annulus size was smaller in R than NR (p = 0.048). Left coronary artery arising posteriorly was associated with a reoperation hazard ratio of 5.2 (p = 0.022). Preoperative anatomy was associated with death and reoperation post-ASO. Small TrAo and TV were risk factors for mortality in univariate analysis, and remained significant in the subset of patients with short circulatory arrest times, suggesting that even when controlling for technical factors, anatomic risk factors predict mortality. Small aortic annulus and posterior left circumflex artery origin were associated with reoperation. Patients with D-TGA, VSD, and AAO constitute a higher risk group, which includes patients who may be marginal candidates for two-ventricle repair.