Dual Antiplatelet Therapy Duration in Elderly Patients
What is the optimal duration of dual antiplatelet therapy (DAPT) after the implantation of a drug-eluting stent (DES) in elderly patients?
The investigators included six randomized trials that compared short-term (≤6 months) and long-term (12 months) DAPT, and individual participant data meta-analysis was performed in elderly patients (≥65 years of age). The primary study outcome was the 12-month risk of a composite of myocardial infarction, definite or probable stent thrombosis, or stroke. The major secondary outcome was the 12-month risk of major bleeding. Endpoints were reported in terms of hazard ratio (HR) and 95% confidence interval (CI), and compared using a Cox regression model stratified by trial, using trial identifiers as random effects. Cumulative event curves were constructed using the Kaplan-Meier method.
The primary outcome risk did not significantly differ between patients receiving short- and long-term DAPT (HR, 1.12; 95% CI, 0.88-1.43; p = 0.3581) in the overall group of study participants. In subgroup analysis, a significant interaction between age and DAPT duration was observed for primary outcome risk (p for interaction = 0.0384). In the subset of younger patients (<65 years of age, n = 6,152), short-term DAPT was associated with higher risk of the primary outcome (HR, 1.67; 95% CI, 1.14-2.44; p = 0.0082). In elderly patients (n = 5,319), however, the risk of the primary outcome did not significantly differ between patients receiving short- and long-term DAPT (HR, 0.84; 95% CI, 0.60-1.16; p = 0.2856). Short-term DAPT was associated with a significant reduction in major bleeding compared with long-term DAPT (HR, 0.50; 95% CI, 0.30-0.84; p = 0.0081) in the overall group, and particularly in elderly patients (HR, 0.46; 95% CI, 0.24-0.88; p = 0.0196).
The authors concluded that short-term DAPT after new-generation DES implantation may be more beneficial in elderly patients than in younger patients with short- versus long-term DAPT.
This meta-analysis of six randomized trials reports that treatment effects were heterogeneous between elderly and younger patients with short- versus long-term DAPT. Short-term DAPT was associated with increased risk of ischemic events in younger patients, but not in elderly patients. However, short-term DAPT was associated with a reduced risk of major bleeding compared with long-term DAPT, suggesting no apparent heterogeneity in different age subgroups. Percutaneous coronary intervention with newer-generation DES requiring DAPT for shorter than 3 months may be an attractive option in the treatment of elderly patients. Additional randomized studies to evaluate optimal duration of DAPT in elderly patients receiving new-generation DES are indicated.
Keywords: Drug-Eluting Stents, Geriatrics, Hemorrhage, Myocardial Infarction, Myocardial Ischemia, Percutaneous Coronary Intervention, Platelet Aggregation Inhibitors, Risk, Secondary Prevention, Stroke, Thrombosis
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