Dual versus single antiplatelet therapy after coronary artery bypass graft surgery: An updated meta-analysis

The potential benefit and risks of dual antiplatelet therapy (DAPT) over single antiplatelet therapy (SAPT) in patients who undergo coronary artery bypass graft surgery (CABG) is controversial.

We performed a systematic review and meta-analysis of observational and randomized clinical trial (RCT) data comparing DAPT to SAPT following urgent or elective CABG. Subanalyses were performed restricted to: a) RCTs; b) stable ischemic heart disease (SIHD); c) extended duration DAPT (≥6 months); and d) follow-up ≥2 years.

Twenty-two studies comprising 20,315 patients undergoing CABG were included. Of the participants studied, 7481 (37%) received postoperative DAPT and 12,834 (63%) received SAPT. Overall, DAPT was associated with a lower cardiovascular (CV) mortality (OR 0.67; p = 0.02) and a trend towards lower all-cause mortality (OR 0.78; p = 0.08). There were no differences in rates of myocardial infarction or stroke. Subanalyses in RCTs, SIHD, and prolonged follow-up failed to demonstrate improvement in these outcomes with DAPT. However, in studies with extended duration DAPT, stroke was significantly reduced in the DAPT group (OR 0.47; p = 0.04). Saphenous vein graft (SVG) occlusion up to 1 year after CABG was significantly lower with DAPT overall (OR 0.64; p < 0.01) and in the RCT subanalysis (OR 0.58; p < 0.01). Major bleeding was significantly higher with DAPT (OR 1.31; p = 0.03).

While DAPT has been associated with lower CV mortality in observational samples undergoing CABG, such findings were not replicated in RCTs. Lower rates of SVG occlusion with DAPT are offset by a higher rate of major bleeding.