This post was authored by Valentin Fuster, PhD, MD, MACC, editor of Journal of the American College of Cardiology.

First, I want to compliment Laura Mauri, MD, and her colleagues for conducting the landmark Dual Antiplatelet Therapy (DAPT) trial, which was presented yesterday at the American Heart Association's Scientific Sessions in Chicago.

Recent guidelines have recommend that patients with coronary artery disease undergoing percutaneous coronary intervention (PCI) discontinue dual-antiplatelet therapy – a combination of aspirin and another platelet inhibitor (e.g., clopidogrel) – within six months to one year. Nevertheless, the U.S. Food and Drug Administration and some clinicians have been concerned about the long-term impact of stents and dual-antiplatelet therapy duration on the adverse outcome of stent thrombosis.

The researchers of DAPT assessed the benefits of 12 versus 30 months of dual-antiplatelet therapy for preventing stent thrombosis and a composite of death, myocardial infarction (MI), or stroke in patients undergoing PCI with drug-eluting stent for the treatment of coronary artery lesions. Importantly, the trial did not include bleeding in their primary composite endpoint.

The researchers found that continued treatment with aspirin and another platelet inhibitor, as compared with aspirin alone, the composite endpoint of major events were reduced (4.3 percent vs. 5.9 percent). This was mainly due to MI, irrespective of the stent thrombosis, which was very low (0.4 percent vs. 1.4 percent). If the trialists had included bleeding as part of their composite endpoint, there would have been very little difference in the final outcomes. Thus, the rate of moderate to severe bleeding was increased with continued aspirin plus another platelet inhibitor, compared with aspirin alone (2.5 percent vs. 1.6 percent).

The results of DAPT align very closely with results of a subgroup analysis in the CHARISMA trial, which involved patients with stable coronary disease who had not undergone PCI. In CHARISMA, the incidence of MI was significantly lower with the combination of aspirin and clopidogrel, compared with aspirin alone.

So, will these results change my practice? I must admit that the DAPT trial won’t change my practice much, because I had believed the results of CHARISMA’s subgroup analysis, and I had tailored my care accordingly.

Then, you may ask what my recommendation would be for patient care based on DAPT. For my patients undergoing stenting, if the patient is at high risk for ischemic events, then I would continue the patient on aspirin plus another platelet inhibitor on a long-term basis. If the patient is at low risk (e.g., minor coronary disease and no previous ischemic events) or has a perceived risk of bleeding, then I would discontinue dual-antiplatelet therapy at six months.

*Note: The ACC/American Heart Association guidelines for PCI, acute coronary syndromes and ST-elevation myocardial infarction already provide a class IIb recommendation for extended DAPT beyond 12 months in selected patients. Extending therapy beyond 12 months should take into account the risk of bleeding. In addition, the U.S. Food and Drug Administration on Nov. 16 issued a statement that it is evaluating the preliminary data from the DAPT trial, but believes the benefits of clopidogrel and prasugrel therapy continue to outweigh their potential risks when used for approved uses. The agency said “health care professionals should not change the way they prescribe these drugs at this time” and advised patients to “not stop taking these drugs because doing so may result in an increased risk of heart attacks, blood clots, strokes, and other major cardiovascular problems.”

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