Abstract
Objectives: To evaluate the effect of clopidogrel vs. aspirin monotherapy on vascular function and hemostatic measurement. Background: Monotherapy with P2Y12 receptor inhibitor vs. aspirin can be a useful alterative to optimize clinical efficacy and safety in high-risk patients with coronary artery disease (CAD). Methods: We performed a randomized, open-label, two-period crossover study in stented patients receiving at least 6-month of dual antiplatelet therapy (DAPT). Thirty CAD patients with moderate-to-high ischemic risk were randomly assigned to receive either 75 mg of clopidogrel or 100 mg of aspirin daily for 4 weeks, and were crossed over to the other strategy for 4 weeks. Vascular function was evaluated with reactive hyperemia-peripheral arterial tonometry (RH-PAT) and brachial-ankle pulse wave velocity (baPWV). Hemostatic profiles were measured with VerifyNow and thromboelastography (TEG). The primary endpoint was the reactive hyperemia index (RHI) during clopidogrel or aspirin monotherapy. Results: Clopidogrel vs. aspirin monotherapy was associated with better endothelial function (RHI: 2.11 ± 0.77% vs. 1.87 ± 0.72%, p = 0.045), lower platelet reactivity (130 ± 64 vs. 214 ± 50 P2Y12 reaction unit [PRU], p < 0.001) and prolonged reaction time (TEG R: 5.5 ± 1.2 vs. 5.1 ± 1.1 min, p = 0.037). In multivariate analysis, normal endothelial function (RHI ≥ 2.1) was significantly associated with clot kinetics (TEG angle ≤ 68 degree) and ‘PRU ≤ 132’. ‘PRU ≤ 132’ was achieved in 46.2% vs. 3.8% during clopidogrel administration vs. aspirin monotherapy (odds ratio 21.4, 95% confidence interval 2.7 to 170.1, p < 0.001). Conclusions: In CAD patients, clopidogrel vs. aspirin monotherapy was associated with better endothelial function, greater platelet inhibition and lower coagulation activity, suggesting pleiotropic effects of clopidogrel on endothelial function and hemostatic profiles.
Highlights
Aspirin monotherapy following 6–12 month dual antiplatelet therapy (DAPT) has been a major secondary prevention strategy in patients with coronary artery disease (CAD)treated with percutaneous coronary intervention (PCI) [1]
A single-center experience suggested that monotherapy with clopidogrel vs. aspirin after 12 months of DAPT was associated with a reduced risk of ischemic events in CAD patients treated with drug-eluting stent (DES) [8]
Previous studies suggested that adjunctive use of P2Y12 inhibitor to aspirin was associated with better endothelial function and low level of inflammation in CAD patients [13,14], but few studies directly compared the effect of clopidogrel vs. aspirin monotherapy on vascular and hemostatic measurements in CAD patients
Summary
Aspirin monotherapy following 6–12 month dual antiplatelet therapy (DAPT) has been a major secondary prevention strategy in patients with coronary artery disease (CAD)treated with percutaneous coronary intervention (PCI) [1]. Monotherapy with a P2Y12 inhibitor following standard duration of DAPT in PCI-treated patients may be a credible alternative strategy [5]. This strategy has demonstrated better clinical outcomes with reduced bleeding risk compared to DAPT [6,7], its clinical benefit was proven for a limited time period (mostly within 6–12 months). A single-center experience suggested that monotherapy with clopidogrel vs aspirin after 12 months of DAPT was associated with a reduced risk of ischemic events in CAD patients treated with drug-eluting stent (DES) [8]. Large-scale clinical trials have been under investigation to evaluate the efficacy and safety of clopidogrel monotherapy beyond 6–18 months in DES-treated patients [9,10]
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