Association of eosinophil-to-monocyte ratio with 1-month and long-term all-cause mortality in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

ST-segment elevation myocardial infarction (STEMI) is a severe type of coronary artery disease (CAD) with high morbidity and mortality (1). Inflammatory and immunological responses play an irreplaceable role in the pathogenesis of STEMI (2,3). Leukocytes including neutrophils (4), monocytes (5), and lymphocytes (6) are indispensable inflammatory cells and are associated with atherosclerosis development and progression, plaque rupture, vascular dysfunction and left ventricular remodeling in STEMI patients (7,8). Recently, neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR) were found to be independent predictive factors of the severity and clinical prognosis of STEMI (9-12). Nevertheless, the association of these individual indexes with cardiovascular diseases has been inconsistent because of their weak specificity (13). There are reports that eosinophils were also inflammatory cells and were able to regulate the inflammatory progress (14). We are not sure whether eosinophil-to-monocyte ratio (EMR) has the similar predictive value as NLR and LMR. This present study assessed the relationship between EMR and one-month and long-term all-cause mortality in STEMI patients undergoing primary percutaneous coronary intervention (P-PCI)