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.