Abstract: Objective To investigate the association between neutrophil to lymphocyte ratio (NLR) and the severity of coronary artery disease in patients with acute coronary syndrome (ACS), and analyze the value of NLR in the diagnosis of acute myocardial infarction. Methods The clinical data of 259 ACS patients with coronary angiography at our hospital from November 2016 to March 2017 were retrospectively analyzed. Among them, there were 148 cases of unstable angina (UA group), 46 cases of acute non-ST elevation myocardial infarction (NSTEMI group), and 65 cases of acute ST-elevation myocardial infarction (STEMI group). The differences of white blood cell count (WBC), neutrophil counts (N), lymphocyte count (L), NLR, hypersensitive c-reactive protein (hs-CRP), myocardial enzyme spectrum, blood lipids, blood glucose, and liver function were compared between the three groups. According to the results of coronary angiography, patients were divided into single-vessel disease group (n=70), double-vessel disease group (n=70) and three-vessel disease group (n=119) in the basis of the number of coronary lesions, and the differences in inflammatory cells were compared between the different-number vessel lesion groups. At the same time, the receiver operating characteristic (ROC) curves of NLR were drawn to evaluate the predictive values of NLR for acute myocardial infarction. Results The levels of WBC, N, NLR, hsCRP, cTnT, CK and CK-MB were significantly higher in turn in UA group, NSTEMI group and STEMI group (P＜0.05).NLR increased gradually with the increased numbers of stenosed coronary artery. The ROC curve showed that the area under the curve of NLR was 0.865 (95%CI: 0.814-0.916)． In addition, the optimal cutoff value of NLR in predicting acute myocardial infarction was 4.22 with sensitivity of 72.1% and specificity of 95.3%. Conclusion NLR levels are positively correlated with the severity of ACS, and which have high value for the diagnosis of acute myocardial infarction, and can be used as a predictor of the condition of ACS patients.

Key words: acute coronary syndrome, acute myocardial infarction, neutrophils, lymphocytes, neutrophils to lymphocytes rate