Clopidogrel Resistance in Japanese Patients Scheduled forPercutaneous Coronary Intervention

Abstract

Background Dual antiplatelet therapy with acetylsalicylic acid (ASA) and a P2Y12 ADP-receptor blocker is standard for prevention of coronary stent thrombosis. Clopidogrel, a 2 nd -generation P2Y12 blocker, has recently become available in Japan and this study aimed to evaluate its antiplatelet effects in Japanese patients. Methods and ResultsThirty Japanese patients scheduled for elective coronary stent implantation were enrolled. Under low-dose ASA therapy, 300 mg clopidogrel was loaded on the 1 st day and a daily 75-mg dose was administered on the following days. Assessed by optical aggregometer, rapid inhibition occurred at 4 h, when the inhibition of platelet aggregation rate (IPA) was 16.4±12.8% using 5 μmol/L ADP as the stimulus. The antiplatelet efficacy of clopidogrel was reasonably constant in each patient throughout the study period, although there was a broad inter-individual variation. At 48 h after clopidogrel loading, the ratios of responders (IPA ≥30%), hypo-responders (10%≤IPA<30%), and non-responders (IPA <10%) were 36%, 50%, and 14%, respectively. Conclusions The antiplatelet effectiveness of clopidogrel appeared individual-specific with wide inter-individual variation. The rate of clopidogrel non-responders was 14% among the examined Japanese patients. (Circ J 2009; 73: 336 -342)

Standard versus high loading doses of clopidogrel in Asian ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention: Insights from the Korea Acute Myocardial Infarction Registry

“…10,14 In Western population, the rates of patients with clopidogrel resistance ranged between 5% and 44%. 15 Hoshino et al 16 showed that the rate of clopidogrel nonresponders was 14% among Japanese patients. We assume that the proportion may be similar in Korean patients.…”

Effects of PPIs and an H2 blocker on the Antiplatelet Function of Clopidogrel in Japanese Patients under Dual Antiplatelet Therapy

“…During DAPT, the antiplatelet effect of clopidogrel could be detected more sensitively using collagen as a stimulus 25) , so we evaluated the aggregation induced by collagen. The MARs induced by 2 μg/mL collagen were 30.5±15.7%, 27.1±15.0%, and 35.7± 15.8% in the control patients, patients taking rabeprazole and those taking omeprazole, respectively (rabeprazole vs. control, p = 0.50, omeprazole vs. control, p = 0.33) (Fig.…”

Prediction of Clopidogrel Low Responders by a Rapid CYP2C19 Activity Test

“…Clopidogrel, a second-generation thienopyridine, is widely used all over the world; however, the antiplatelet effect of clopidogrel varies widely among individuals and some patients exhibit little clopidogrel effect [2][3][4][5][6] . In such patients with low response to clopidogrel, the incidence of cardiovascular event is increased after PCI [7][8][9] .…”