Abstract: AIM:To investigate the correlation between peripheral blood plasma endothelium particles (EMP) and reperfusion injury in patients with ST-elevated myocardial infarction (STEMI) or non-ST-elevated myocardial infarction (NSTEMI). METHODS: A total of 45 patients with myocardial infarction were eligible for this study, including STEMI patients (n=35) and NSTEMI patients (n=10). STEMI patients received primary PCI in the “infarct-related artery” within 12 h and NSTEMI patients received selective PCI within 48 h, respectively. Sirolimus-eluting stents were used in all patients. Changes in concentrations of plasma EMP were detected using flow cytometer assay and the correlation between EMP and myocardial reperfusion injury was assessed. RESULTS: EMP increased markedly in both STEMI and NSTEMI patients receiving PCI. At 1 h after PCI, the elevation in the peak of plasma EMP in STEMI patients was more noticeable than in NSTEMI patients (P<0.05). Such a result was also detected in the increase of CKMB. CONCLUSION: The dynamic changes of EMP in plasma after PCI are related to the different types of acute myocardial infarction.