New guidelines for dual antiplatelet therapy in patients with CAD

The American Heart Association and the American College of Cardiology recently updated guidelines on the recommended duration of dual antiplatelet therapy (DAPT) for patients with coronary artery disease (CAD).

The recommendations define DAPT as aspirin plus a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor). The full guidelines were published online on March 29 by Circulation and the Journal of the American College of Cardiology.

The update implements findings on the duration of DAPT from 11 studies published after 6 previous sets of recommendations: percutaneous coronary intervention (2011), coronary artery bypass graft surgery (2011), diagnosis and management of patients with stable ischemic heart disease (2012), ST-elevation myocardial infarction (2013), non-ST-elevation acute coronary syndromes (2014), and perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery (2014).

Some highlights from the guidelines are as follows:

• Clinicians should weigh ischemic risks and bleeding risks before adding a P2Y12 inhibitor to aspirin monotherapy or prolonging DAPT. In addition to considering the benefits and risks for individual patients, they should also assess relevant study data and patient preferences.
• In patients treated with DAPT, the recommended daily dose of aspirin is 81 mg (with anything between 75 mg and 100 mg being in the optimal range). Compared to higher aspirin doses, lower doses are associated with lower bleeding complications and comparable ischemic protection.
• In most clinical settings, DAPT should be continued for at least 6 to 12 months. It may be reasonable to prolong DAPT beyond this period for some patients. In general, clinicians may consider shorter-duration DAPT for patients at lower ischemic risk with high bleeding risk, and longer-duration DAPT may be reasonable for patients at higher ischemic risk with lower bleeding risk.
• Recommendations for duration of DAPT are now similar for patients with non-ST-segment-elevation acute coronary syndromes and ST-segment-elevation myocardial infarction because both are on the spectrum of acute coronary syndrome.
• These recommendations apply specifically to duration of P2Y12 inhibitor therapy as part of DAPT. In almost every case, aspirin should be continued indefinitely in patients with CAD.

The guidelines also specifically addressed patients with stents, noting that prior recommendations regarding duration of DAPT for patients with drug-eluting stents were based on data from the first generation of devices, which are rarely used in current practice. The new guidelines apply to newer stents, which have a more favorable safety profile and pose a lower risk of stent thrombosis. The authors noted that studies involving patients on prolonged DAPT after implantation of a drug-eluting stent have limited duration of therapy to several years. Therefore, the true optimal duration of therapy is undetermined in patients with a benefit-risk ratio that suggests prolonged therapy, the guidelines said.

The guideline update was based on a systematic review, also published in Circulation and JACC.