Abstract: AIM To investigate the effect of long-term loading dose of clopidogrel on the incidence of cardiovascular ischemic events in patients with high platelet reactivity who underwent percutaneous coronary intervention. METHODS Thrombelastograph was used to detect the effect of clopidogrel in 120 high platelet reactivity patients undergoing PCI and who were insensitive to clopidogrel. Patients were divided randomly into control group (n=60) and drug-test group (n=60). Patients in control group were given 100 mg of aspirin and 75 mg clopidogrel daily, and patients in drug-test group were given 100 mg of aspirin and 150 mg clopidogrel daily. A 6-month follow-up was conducted to examine the incidence of cardiovascular ischemic events. RESULTS After the 6-month antiplatelet therapy, the inhibition ratio of clopidogrel in drug-test group was significantly higher than in control group ［(68±5)% vs.(42±7)%, P<0.05］. The rate of occurrence of cardiovascular ischemic events including cardiovascular death, stent thrombosis, recurrent unstable angina and myocardial infarction in drug-test group was 0, 10, 23 and 6%, respectively, and decreased significantly compared with those in the control group (3, 20, 36 and 17%, respectively, P<0.05). CONCLUSION The maintenance loading dose of antiplatelet therapy with 150 mg clopidogrel daily can effectively decrease the rate of recurrent cardiovascular ischemic events.