Association of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios with coronary artery disease severity

Introduction: Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are two measurable parameters through complete blood count (CBC), whose role has recently been considered as inflammatory markers with potential in predicting cardiovascular events. The purpose of this study was to determine the association of NLR and PLR with coronary angiographic findings in patients with acute coronary syndrome (ACS). Methods: This cross-sectional study was conducted on hospitalized patients diagnosed with ACS who underwent angiography. The patients were divided into two groups according to coronary circulation status in the angiography: 1) spontaneous reperfusion group (SRG) consisting of patients with normal coronary circulation and TIMI flow grade of 3; 2) non-SRG group including patients with some degree of impaired coronary circulation and TIMI flow grade of <= 2. Then clinical, laboratory, echocardiographic and angiographic findings were compared. The ROC curve was used to calculate a suitable cut-off point from PLR and NLR to predict the severity of coronary artery involvement and to differentiate SRG from non-SRG. Independent sample t-test, Chi-Square, and logistic regression were applied for statistical analysis. Results: The study consisted of 360 patients (224 males and 136 females) with a mean age of 60.7 +/- 12.3 years. According to the angiography, 134 (37.2%) patients were assigned to the SRG group and 226 (62.8%) patients to the non-SRG group. Comparison of laboratory findings in the two groups of SRG and non-SRG showed that white blood cell count, platelet count, neutrophil count, troponin I level, NLR and PLR were significantly higher in the abnormal group. The best cut-off point of PLR and NLR in the non-SRG prediction was 103 and 3.3 in the ACS patients, respectively. The area under the ROC curve, sensitivity and specificity of obtained cut-off points were determined to be 66.6, 73.1%, and 54.5% for the PLR (95% CI=61.5-71.4), and 68.3, 46.9%, and 82.0% for NLR (95% CI=63.2-73.1), respectively. Conclusion: In the ACS patients, the coronary atherosclerosis is associated with inflammatory markers, and PLR and NLR can be used to evaluate the severity of coronary artery involvement.