Abstract: Objective To compare the effects of different antiplatelet therapy on outcomes in patients with acute coronary syndrome (ACS). Methods 338 hospitalized patients with ACS were enrolled. They were assigned to three groups: group 1, aspirin alone after discharge, n=93; group 2, dual antiplatelet treatment of aspirin and clopidogrel after discharge for 6～12 months, then aspirin, n=127; and group 3, dual antiplatelet treatment of aspirin and clopidogrel after discharge for 2 years, n=118. All the patients were followed up for 2 years. The clinical data (basic clinical data, platelet count and serum lipids indeices), primary end point (cardiovascular death, nonfatal myocardial infarction and stroke) and hemorrhagic events (major hemorrhage, moderate hemorrhage and minor hemorrhage) within 1 and 2 years were analyzed. Results During 1 and 2 years, compared with group 1, the incidence of cardiovascular death and all primary end points of groups 2 and 3 decreased significantly (P＜0.05), but the nonfatal myocardial infarction and stroke did not （P＞0.05）. The difference was not statistically significant between groups 2 and 3 in all the end points （P＞0.05）. The difference of hemorrhagic events was not statistically significant among the 3 groups（P＞0.05）. Conclusion Dual antiplatelet treatment of clopidogrel plus aspirin for 2 years may decrease the mortality of cardiovascular disease while the incidence of severe hemorrhage doesn't increase.

Key words: acute coronary syndrome, clopidogrel, platelet