Post-CABG Bleed Risk Climbs When Anticoagulants Added to Dual Antiplatelets

Abdullah Hashmi, MD, for Medscape

April 25, 2022

The study covered in this summary was published in as a preprint and has not yet been peer reviewed.

Key Takeaways

  • Among patients undergoing coronary artery bypass graft (CABG) surgery, those who received single-antiplatelet therapy with aspirin (ASA) or dual-antiplatelet therapy (DAPT) with aspirin plus clopidogrel showed no difference in risk for major bleeding or postoperative mortality.

  • The risk of bleeding events was increased in patients receiving anticoagulation therapy with either ASA or DAPT.

  • Postoperative anticoagulant therapy and early use of heparin were independently associated with increased bleeding-related events.

Why This Matters

  • Current guidelines do not include recommendations for the early use of anticoagulants after CABG, and whether anticoagulant therapy is safe and effective in preventing early adverse events is unknown.

  • DAPT is as safe as ASA after CABG, the current study suggests, but the addition of anticoagulation therapy to either increased the risk of bleeding and should be considered cautiously in clinical practice. 

Study Design

  • The observational study involved 3274 patients in the Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC III) database who underwent isolated CABG.

  • Patients were grouped according to postoperative antithrombotic therapy; 73% of patients received single-antiplatelet therapy with ASA and 27% received DAPT.

  • Those two groups were further subdivided by use of oral and parenteral anticoagulants. About 33% of both the ASA and DAPT groups received some form of anticoagulation after surgery.

  • The primary endpoint was postoperative bleeding that met PLATO, TIMI, and GUSTO criteria. Secondary endpoints included 30-day postoperative mortality, postoperative MI, stroke, and the composite of mortality, MI, and stroke.

Key Results

  • Among the groups, the DAPT group had a higher proportion of patients with peripheral artery disease or a history of percutaneous coronary intervention (PCI) or CABG.

  • There was no difference in rate of PLATO, TIMI, or GUSTO major bleeding between the ASA and DAPT groups (28.8% and 28.1%, respectively; P = .700).

  • The DAPT and ASA groups showed no significant difference in 30-day mortality (1.8% vs 1.4%; P = .437).

  • The composite secondary endpoint was marginally increased in the DAPT group (4.0% vs 2.7%; P = .043).

  • Patients receiving ASA and anticoagulants, compared with ASA alone, showed an increased risk for PLATO major bleeding, TIMI major bleeding, and GUSTO severe bleeding, as well as higher rates of reoperation due to bleeding, hemoglobin decrease, and packed red blood cell (PRBC) and platelet transfusion. 

  • Patients receiving DAPT plus anticoagulants, compared with DAPT alone, had higher rates of PLATO major bleeding, TIMI minor bleeding, and PRBC and platelet transfusion.

  • Postoperative DAPT was not a significant predictor of severe bleeding or mortality in multivariate analysis.

  • Patients receiving postoperative anticoagulants that included early use (within 48 hours) of heparin had increased rates of PLATO major bleeding, hemoglobin decrease, and PRBC transfusion.

  • Postoperative heparin was associated with increased 30-day mortality and stroke. 


  • There may have been confounding variables that were not accounted for in the observational, retrospective study.

  • The analysis did not distinguish among different types of anticoagulant, and the low prevalence of early heparin use could have biased the results.

  • Antithrombotic therapy duration was not examined.


  • The study received no commercial funding.

  • None of the authors disclosed relevant financial relationships.

This is a summary of a preprint research study, Different antithrombotic strategies after coronary artery bypass grafting to prevent adverse events, written by researchers at Peking University People’s Hospital, Beijing, on ResearchSquare provided to you by Medscape. The study has not yet been peer-reviewed. The full text of the study can be found on


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