Preoperative SYNTAX score and graft patency after off-pump coronary bypass surgery†

Abstract

We examined the association between the preoperative SYNTAX score and graft patency after off-pump coronary artery bypass surgery (CABG). Of 912 consecutive patients undergoing isolated CABG (906 by the off-pump technique) between 2002 and 2011, 217 underwent computed tomography (CT) angiography. From this cohort, we studied 189 patients for whom preoperative SYNTAX scores were retrospectively obtained. The primary endpoint was at least one graft occlusion on the follow-up CT angiography. Graft occlusion was defined as the absence of contrast agent along the course of the graft. In sequential grafts, each segment was analysed as a separate graft. The secondary endpoint was a composite of major adverse cardiac and cerebrovascular events (MACCE), which was defined as cerebrovascular accident, non-fatal myocardial infarction, admission due to pump failure and repeated revascularization. All arterial conduits were harvested with the skeletonization technique and used as in-situ grafts except one right-side internal thoracic artery (ITA). The mean interval from operation to angiogram was 4.7 ± 2.4 years, range 0.8-10.0 years. Estimated 8-year graft patencies of ITA- left anterior descending artery, ITA-circumflex branch (CX), saphenous vein -CX and/or posterior descending artery (PDA), and gastroepiploic artery -PDA were 97.4 ± 1.5, 89.3 ± 4.2, 86.5 ± 6.7, and 86.2 ± 5.7%, respectively. Of the 666 total distal anastomoses, 27 in 21 patients were occluded. No significant difference was found in the preoperative SYNTAX scores between the 21 patients with at least one graft occlusion (mean 35.7; range 15.0-51.5) and the 168 patients without graft occlusion (mean 36.6; range 17.0-54.5) (unpaired t-test, P = 0.87). In univariate and multivariate logistic regression models, no significant association was found between at least one graft occlusion and individual components of the SYNTAX score. There was no significant difference in patients with low (≤ 22), intermediate (23-32) and high (≥ 33) SYNTAX scores in the cumulative rates of at least one graft occlusion (log-rank test, P = 0.88) and MACCE (log-rank test, P = 0.86). The preoperative SYNTAX score and its individual components are not associated with graft occlusion after off-pump CABG.