Serum myeloperoxidase: a novel biomarker for evaluation of patients with acute coronary syndrome

Objectives Myeloperoxidase, an abundant leucocyte enzyme, is elevated in culprit lesions that have ruptured in patients with sudden cardiac injury. Multiple lines of evidence suggest an association between myeloperoxidase and inflammation and acute coronary syndrome. Myeloperoxidase has been proposed as a potent risk marker and diagnostic tool in acute coronary syndrome (ACS). Recent studies have reported the potential use of myeloperoxidase in acute coronary syndrome, but limited reports are available on its utility in different groups of ACS in the emergency department. Therefore the circulating levels of serum myeloperoxidase in patients with acute coronary syndrome and control subjects were studied. Design and setting The levels of serum myeloperoxidase were measured by ELISA in 485 patients admitted to emergency care unit, of which 89 patients were diagnosed as non-cardiac chest pain (NCCP). The levels of myeloperoxidase were significantly increased in patients with ACS when compared with controls and NCCP. From the receiver operator characteristic (ROC) curve analysis, the optimum value above which myeloperoxidase can be considered positive was found to be 48.02 U/ml. The area under the curve was found to be 0.956 with 95% CI (0.934 to 0.973) (p<0.0001). A combination analysis of ROC curves of troponin, creatine kinase MB (CK-MB) and myeloperoxidase showed myeloperoxidase to be highly significant. Multivariate analysis revealed myeloperoxidase to be an independent diagnostic marker for early diagnosis of ACS. Conclusion Myeloperoxidase, in contrast to troponin and CK-MB, identified patients at risk of ischaemic events, even in the absence of myocardial necrosis, thus highlighting its potent usefulness for risk stratification among patients presenting with chest pain.