Quantification of Endothelial Microparticles on Modified Cytometric Bead Assay and Prognosis in Chest Pain Patients

Background: Endothelial microparticles (EMPs) are vehicles released from activated or apoptotic endothelium. The aim of this study was to establish a new cytometric bead assay for EMPs and investigate the prognostic value of EMPs in chest pain patients. Methods and Results: We invented and verified the cytometric bead assay to quantify EMP level in vitro. A total of 80 healthy volunteers and 350 chest pain patients were recruited and the EMPs measured. The major adverse cardiovascular events (MACE) of documented coronary artery disease patients were recorded in the follow-up period. The level of EMPs statistically correlated with those of endothelin-1 (ET-1) and intercellular adhesion molecule-1 (ICAM-1) in vitro. The EMP level in healthy subjects was <300.10. The patients had a remarkably higher EMP level than healthy subjects. Diabetes mellitus, EMP, and ET-1 levels were significantly associated with future cardiovascular events in chest pain patients. There was a significantly higher event incidence in the top tertile EMP level than in the lower tertile in the acute coronary syndrome (ACS) patient group. Conclusions: A novel EMP quantification assay has been successfully established. The EMPs in vitro and in patients were significantly correlated with ET-1 and ICAM-1 level. The patients with a higher EMP level had a higher risk of MACE. EMP level is a predictor for MACE in ACS patients.