DAPT vs. Aspirin Monotherapy in Diabetics Undergoing CABG
What are the dual antiplatelet therapy (DAPT) utilization rates and associated outcomes among post-coronary artery bypass grafting (CABG) patients with diabetes?
In a post-hoc, nonrandomized analysis from the FREEDOM (Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease) trial, the investigators compared patients receiving DAPT (aspirin plus thienopyridine) and aspirin monotherapy at 30 days postoperatively. The primary outcome was the risk-adjusted 5-year FREEDOM composite of all-cause mortality, nonfatal myocardial infarction, or stroke. Safety outcomes included major bleeding, blood transfusion, and hospitalization for bleeding. The differences between the two treatment groups were tested using Kruskal-Wallis test statistics. The times to primary, secondary, and safety outcomes were analyzed using Cox proportional hazard regression.
At 30 days post-CABG, 544 (68.4%) patients received DAPT and 251 (31.6%) patients received aspirin alone. The median duration of clopidogrel therapy was 0.98 (0.23-1.91) years. There was no significant difference in the 5-year primary composite outcome between DAPT and aspirin-treated patients (12.6% vs. 16.0%, adjusted hazard ratio [HR], 0.83; 95% confidence interval [CI], 0.54-1.27; p = 0.39). The 5-year primary composite outcomes were similar for patients receiving DAPT versus aspirin monotherapy respectively, in subgroups with pre-CABG acute coronary syndrome (15.2% vs. 16.5%, HR, 1.06; 95% CI, 0.53-2.10; p = 0.88) and those with stable angina (11.6% vs. 15.8%, HR, 0.82; 95% CI, 0.50-1.343; p = 0.42). The composite outcomes of both treatment groups were also similar by SYNTAX score, duration of DAPT therapy, completeness of revascularization, and in off-pump CABG. No treatment-related differences in major bleeding (5.6% vs. 5.7%, HR, 1.00; 95% CI, 0.50-1.99; p = 0.99), blood transfusions (4.8% vs. 4.5%, HR, 1.09; 95% CI, 0.51-2.34; p = 0.82), or hospitalization for bleeding (2.6% vs. 3.3%, HR, 0.85; 95% CI, 0.34-2.17; p = 0.74) were observed between aspirin and DAPT-treated patients, respectively.
The authors concluded that compared with aspirin monotherapy, no associated differences were observed in cardiovascular or bleeding outcomes, suggesting that routine use of DAPT may not be clinically warranted.
This post-hoc secondary analysis of the FREEDOM trial with centrally adjudicated clinical outcomes compared aspirin monotherapy with DAPT post-CABG in patients with diabetes and reports that there were no significant differences in either the primary composite outcome (all-cause death, MI, or stroke) or bleeding outcomes between aspirin and DAPT-treated patients. Furthermore, results were similar across clinically important subgroups including preoperative acute coronary syndrome, SYNTAX score, complete revascularization, and duration of DAPT. The routine use of DAPT in post-CABG diabetic patients should be reassessed in an adequately powered, prospective, randomized clinical outcome trial.
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