Clopidogrel Resistance is Associated with Long-Term Thrombotic Events in Patients Implanted with Drug-Eluting Stents

Background: There are limited prospective data on clopidogrel resistance and clinical outcome of patients with selective coronary drug-eluting stent (DES) implantation. Objective: To investigate whether clopidogrel resistance is associated with longterm thrombotic events in patients with selective coronary DES implantation. Methods: A total of 154 patients who underwent selective percutaneous coronary intervention (PCI) with DES were enrolled in this study. Platelet aggregation was measured using light transmittance aggregometry (LTA) before clopidogrel administration (baseline) and 24 hours after loading with clopidogrel 300 mg. Clopidogrel resistance was defined as ≤10% absolute difference between baseline aggregation and post-administration aggregation. All patients who received the same anti-platelet treatment were followed up for 1 year after discharge for the incidence of a composite endpoint consisting of cardiovascular death, myocardial infarction (MI) and revascularization, and secondly for the incidence of stent thrombosis. Results: The incidence of clopidogrel resistance is 20.28% in our study population. Patients who are complicated by diabetes mellitus, smoke, or have a higher body mass index (BMI) tend to have clopidogrel resistance. Patients in the clopidogrel-resistant group have significantly higher incidences of composite endpoints (21.88% vs 4.92%; p = 0.006) and stent thrombosis (12.5% vs 1.64%; p= 0.017) than patients in the clopidogrel-response group during 1-year follow-up. Conclusions: Diabetes, smoking, and high BMI are associated with clopidogrel resistance, and clopidogrel resistance indicates an increased risk of long-term thrombotic events in patients implanted with DES.