Associations of myeloperoxidase, as a marker of oxidative stress and plaque instability, with coronary artery disease and cardiovascular event

Abstract

Background: Myeloperoxidase (MPO) may be a useful marker for oxidative stress and plaque instability. Recent studies have shown that plasma MPO is elevated in patients with unstable angina and acute myocardial infarction. However, its prognostic value remains unclear. The aim of this study was to investigate associations of MPO with coronary artery disease and cardiovascular event. Methods and results: 215 patients (mean age 66±10 years) undergoing coronary angiography (CAG) were enrolled and divided into three groups: acute coronary syndrome (ACS, n=144), stable angina pectoris (SAP, n=49) and healthy people (Control, n=22) in the cross-sectional study. Each coronary risk factors and patients characteristic were evaluated. Plasma MPO level were determined by immunoassay Abbott Architect and other laboratory data were measured by standard laboratory methods. These Data were examined statistically. A cardiac event, which was defined as cardiac death, rehospitalization for ACS, rehospitalization for worsening heart failure, or coronary restenosis, was monitored for 12 months after admission. Statistically, plasma MPO levels were higher in ACS patients (284.6±14.3 pmol/ml) than in SAP (155.2±12 pmol/ml) and healthy control (50±1.5 pmol/ml) (P<0.05). HsCRP (high sensitive C-reaction protein) and BNP (brain natriuretic peptide) were significantly increased in ACS patients over SAP patients and Control patients. Additionally, adrenalin induced aggregation levels were significantly decreased in ACS patients over other groups (80±3.5%, 60±4.8% vs. 41.8±4.3%, P<0.05). Furthermore, a total of 50 (34.7%) cardiovascular events occurred during the 1 year follow-up period. The cardiovascular event rate was higher in patients with increased MPO. A Kaplan-Meier analysis revealed that patients with increased MPO had a higher risk for cardiac events than those without (P<0.05). Conclusion: This study shows that measurement of plasma MPO may be considered to be a sensitive and specific biomarker for diagnosis of ACS and may substantially improve the early risk stratification of patients with coronary artery disease, and suggests a possibility that plasma MPO level may become one element which predicts a cardiovascular event.