Predictive value of myeloperoxidase to identify high risk patients admitted to the hospital with acute chest pain.

BACKGROUND: Myeloperoxidase (MPO) is a highly expressed enzyme due to leukocyte activation, with multiple atherogenic actions, including LDL cholesterol oxidation, and is related to the instability of atherosclerotic plaque. It is a predictor of adverse events in healthy individuals, patients with heart disease or those undergoing chest pain investigations.

OBJECTIVE: To analyze the contribution of MPO to identify patients with acute chest pain, non-ST elevation ECG and at high risk for in-hospital adverse events.

METHODS: Patients presenting acute chest pain and a non-ST elevation ECG, were admitted to the hospital and submitted to serum MPO level measurements and a structured examination protocol.

RESULTS: From a cohort of 140 patients, 49 (35%) were diagnosed with acute coronary syndrome, of which 13 patients (9.3%) were diagnosed with non-ST elevation acute myocardial infarction (AMI) (troponin I >1.0 ng/mL). The best MPO cut-off point for AMI was identified as >100 pM using the ROC curve (AUC=0.662; CI 95%=0.532-0.793) revealing elevated sensitivity (92.3%) and negative predictive value (98.1%), however with low specificity (40.2%). In the multivariate analysis, MPO proved to be the only independent variable to diagnose AMI in evolution, with an odds ratio of 8.04 (p=0.048).

CONCLUSION: In patients with acute chest pain and no ST elevation, high MPO levels upon admission to the hospital are an important tool to predict in-hospital adverse events, with an odds ratio of eight for the diagnosis of AMI.