Effects of Nonadherence to Dual Antiplatelet Therapy | Journal Scan

Study Questions:

What is the frequency and clinical impact of dual antiplatelet therapy (DAPT) nonadherence?


The EDUCATE (Endeavor Drug-Eluting Stenting: Understanding Care, Antiplatelet Agents and Thrombotic Events) registry is a prospective registry to assess practice patterns and patient adherence to DAPT and the risk of subsequent thrombotic events. After successful Endeavor zotarolimus-eluting stent implantation, 2,265 patients were enrolled in this registry with limited exclusions and monitored during 12 months of prescribed DAPT. Predictors of any nonadherence (ANA) at 6 months were analyzed by multivariable analysis, and the association between ANA at 6 or 12 months with the endpoints of death, myocardial infarction (MI), and stent thrombosis was assessed.


The study population included 30% female patients, 34% with diabetes, and 36% with acute coronary syndromes. ANA occurred in 208 patients (9.6%) before 6 months and 378 patients (18.5%) before 1 year. Major bleeding (odds ratio [OR], 12.83; 95% confidence interval [CI], 7.55-21.80; p < 0.001) was the only predictor of ANA at 6 months. In time-dependent analyses, ANA before 6 months was associated with an increased risk of death or MI (7.6% vs. 3.0%; p < 0.001) and a numerical increase in stent thrombosis (2.0% vs. 0.9%; p = 0.12). After adjustment for baseline differences, ANA within 6 months remained associated with death or MI (OR, 1.95; 95% CI, 1.02-3.75). ANA occurring after 6 months did not increase the risk of subsequent ischemic events.


The authors concluded that DAPT nonadherence occurs frequently and is associated with increased risk for thrombotic complications if it occurs within the first 6 months.


This multicenter international registry of patients undergoing stenting with the E-ZES reports that nonadherence with the prescribed 12 months of DAPT was frequent, including prolonged (>14 days) nonadherence in over 5% of patients within 6 months of DES implantation. Nonadherence in the first 6 months correlated strongly with the occurrence of major bleeding and was independently associated with adverse thrombotic outcomes at 1 year. For patients fully compliant with DAPT during the first 6 months after E-ZES implantation, subsequent nonadherence between 6 and 12 months did not confer increased ischemic risk. While the optimal duration of DAPT after newer-generation DES remains a matter of debate, uninterrupted DAPT therapy of at least 6 months and preferably 12 months is indicated for most patients undergoing percutaneous coronary intervention.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Drug-Eluting Stents, Stents, Percutaneous Coronary Intervention, Platelet Aggregation Inhibitors, Thrombosis, Myocardial Infarction, Prospective Studies, Registries, Patient Compliance, Risk

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