Despite clear recommendations from the American College of Cardiology/American Heart Association (ACC/AHA) guidelines,1 a number of recent studies have demonstrated there is ample room for improvement in the use of antiplatelet agents in the management of patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS). Both clinical practice uptake and patient adherence have been suboptimal.2
What Do the Guidelines Say?
In an interview with Cardiology Advisor, Dr Donald Cutlip, director of the Cardiac Catheterization Laboratory in the Cardiovascular Institute at Beth Israel Deaconess Medical Center and professor of medicine at Harvard Medical School, summarized the guideline recommendations on the use of antiplatelet agents. “The ACC/AHA guideline document is reasonably clear on recommendations for antiplatelet therapy in ACS patients. This includes aspirin indefinitely and a P2Y12 inhibitor for up to 12 months regardless of ischemia-guided or invasive strategy and at least 12 months if patients receive a coronary stent. However, the guideline also addresses the issue in patients at high bleeding risk; specifically those patients with a clear indication for anticoagulant therapy (ie, triple therapy [dual antiplatelet therapy plus anticoagulation]). Although not specific in recommendations, the guideline notes the duration of triple therapy should be minimized in this population.”
Dr Cutlip also noted that with bare-metal stents or newer-generation drug-eluting stents (DES), duration of dual antiplatelet therapy (DAPT) lasting less than 12 months—as short as 1 to 3 months in some cases—or the use of clopidogrel and an anticoagulant without aspirin, as described in the WOEST (What is the Optimal Antiplatelet and Anticoagulant Therapy in Patients with Oral Anticoagulation and Coronary Stenting) trial may be justified.3
“In summary, patients who are not at high bleeding risk should be treated with aspirin (probably 75 mg to 81 mg) indefinitely and a P2Y12 inhibitor for at least 12 months with preference for ticagrelor if ischemia-guided strategy and ticagrelor or prasugrel if a coronary stent is implanted,” Dr Cutlip stated.
The WOEST trial compared triple therapy with aspirin, clopidogrel, and warfarin to dual therapy with clopidogrel and warfarin.3
Examining the Evidence: Consequences of Nonadherence
Nonadherence to DAPT has serious consequences, including excess mortality. Dr Rajiv Chowdhury, of the University of Cambridge, and his team conducted a systematic review and meta-analysis of prospective studies reporting risk estimates of cardiovascular medication adherence with any cardiovascular disease (CVD) and/or all-cause mortality. Results published in the European Heart Journal in 2013 showed that a substantial proportion of patients exhibited suboptimal adherence across all individual CVD medications, including antiplatelet therapy. The team estimated that poor medication adherence to CVD medication was responsible for 13 per 100 000 deaths due to CVD annually, and approximately 9% of all CVD cases in the European Union may be attributable to poor adherence. They calculated that good adherence to cardiac therapies has the potential to lower the risk of CVD by 20% and all-cause mortality by 35%.2