Objective To investigate the expression level of urokinase plasminogen activator receptor (uPAR) in monocytes in coronary heart disease (CHD) patients before and after percutaneous coronary intervention (PCI) and to determine the relationship between uPAR and major adverse cardiac events (MACE).Methods A consecutive cohort of 136 CHD patients were enrolled,including 85 acute coronary syndrome (ACS) patients and 51 stable angina pectoris (SAP) patients.Twenty healthy volunteers were taken as control group.Peripheral blood samples were collected,and uPAR expression in monocytes was measured by flow cytometry at 24 h,48 h,and 3 months after PCI treatment.MACE were recorded during 2-year followe-up.Results Expression level of uPAR was significantly higher in ACS patients than in SAP patients and healthy controls(P<0.01).In ACS group,the expression level of uPAR decreased significantly at 3 months after PCI(P<0.01).Among 85 ACS patients who were followed up for an average of (20.46±2.45) months,24 MACE were reported.The expression level of uPAR in MACE group was significantly higher than that in non-MACE group(P<0.01).Ordinal logistic regression analysis revealed that the level of uPAR expression in monocytes was significantly correlated to MACE.Conclusion The level of uPAR expression in monocytes in ACS group is significantly higher than that in SAP group.Expression level of uPAR in ACS patients is significantly correlated to MACE.uPAR is a sensitive predictor for the severity of CHD,and is of great significance in evaluating the stability of atheromatous plaque and the outcome of CHD.