Dual antiplatelet therapy versus aspirin monotherapy in diabetics with stable ischemic heart disease undergoing coronary artery bypass grafting

Background: Dual antiplatelet therapy (DAPT) in patients presenting with acute coronary syndrome (ACS) undergoing CABG is recommended to prevent recurrent ischemic events. The benefit of DAPT post-CABG in patients with stable ischemic heart disease (SIHD) is unknown. The aim of this study was to evaluate the utilization rate of DAPT and associated outcomes in patients with SIHD undergoing CABG via a secondary analysis of Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial data.
Methods: In a post-hoc, nonrandomized analysis from the BARI 2D trial, we compared patients receiving DAPT and aspirin monotherapy within 90 days post-randomization. The primary outcome was the risk adjusted 5-year composite of all-cause mortality, nonfatal myocardial infarction (MI), or stroke. We analyzed patients assigned to prompt CABG treatment arm including both the insulin therapy assignments.
Results: Of 378 patients, within 90 days post-randomization, 59 (16%) patients received DAPT and 319 (84%) patients received aspirin alone. Cox proportional hazard analysis demonstrated that there was no significant difference in the 5-year composite event of death, MI, and stroke between DAPT and monotherapy cohorts [13 (22.0%) vs. 61 (19.1%); adjusted hazard ratio (HR): 1.06; 95% confidence interval (CI): 0.56 to 2.00; P=0.86]. There also was no significant difference at 1 year in the composite event [6 (10.2%) vs. 30 (9.4%); HR: 1.13; 95% CI: 0.46 to 2.79; P=0.79].
Conclusions: The use of DAPT in patients with diabetes post-CABG in this cohort was low. Compared with aspirin monotherapy, no associated differences were observed in cardiovascular outcomes. Larger prospective studies are needed to further elucidate this observation.