Abstract: Objective　To study the level and its clinical significance of peripheral blood erythropoietin（EPO） in patients with acute coronary syndrome （ACS）.   Methods　The serum EPO levels were measured by enzyme-linked immunosorbent assay in 68 patients with ACS [35 patients with acute myocardial infarction （AMI） and 33 patients with unstable angina pectoris（UAP）]，28 patients with stable angina pectoris（SAP） and 30 controls with normal coronary arteriography. The ACS patients were classified into intracoronary stent implantation group (26 cases) and un-implantation group (42 cases). Results　The serum EPO level in ACS group [(1.21±0.27)mg/L] was significantly higher than that in SAP group [(0.90±0.23)mg/L] and that in control group [(0.81±0.36)mg/L](P＜0.01). The serum EPO level in AMI group was higher than those in UAP group and control group（P＜0.05）. The serum EPO level in implantation group was higher than that in un-implantation group（P＜0.05）. Conclusions　The serum EPO level is related with ACS. The serum EPO level will increase in ACS patients with intracoronary stent implantation.

Key words: Erythropoietin, Acute coronary syndrome, Coronary artery disease