IJCS | Volume 31, Nº5, September / October 2018

534 Santos & Izidoro NLR in CVD risk assessment Int J Cardiovasc Sci. 2018;31(5)532-537 Review Article processes triggered during atherosclerotic lesions. 27 On the other hand, the quantitative increase in neutrophils is also related to the atherogenic process, acting through lipid mediation, necrosis and inflammation, secreting chemokines and cytokines. This cell type regulates ICAM-1 and expresses MPO, a protein that contributes to the formation of free radicals, promoting greater LDL oxidation, exacerbating the pathological process. 11 Based on the interpretation of the NLR results, it is possible to predict the presence of atherosclerotic processes before the coronary angiography is performed. 28,31 Additionally, this tool is useful to help attain a diagnosis of acute myocardial infarction more quickly and can be used in emergency situations in medical care units. 32 The NLR is commonly increased in patients with coronary disease when compared to healthy patients. Neutrophil values and NLR are also correlated with the number of noncalcified atherosclerotic plaques, as shown by coronary assessment through angiotomography and invasive angiography. 30 Patients with total coronary occlusion also have a higher NLR value, being significantly more pronounced than in patients with normal coronary arteries (p < 0.001). 33 In a study of 194 volunteers with coronary artery disease submitted to coronary angiography, 19 those with severe atherosclerosis had higher neutrophil and lower lymphocyte percentages when compared to patients with mild atherosclerosis and normal individuals, and the NLR was higher than 2.5 in these conditions. Recently, computed tomography coronary angiography studies have shown that increased NLR is associated with the presence, severity, and extent of atherosclerotic plaques in coronary arteries. A higher white cell and neutrophil counts and a lower absolute lymphocyte count were observed in the patients. A value of NLR higher than 2.25 increased the likelihood of developing coronary atherosclerosis (OR = 2.30) and critical luminal stenosis (OR = 2.60). 17 The detection of obstructive coronary disease and coronary calcium score was significantly higher in type 2 diabetic patients with NLR higher than 2.05, when compared to patients with type 2 diabetes and NLR lower than or equal to 2.05. 34 In a retrospective study, it was observed that of 2,121 patients diagnosed with peripheral obstructive arterial disease and with NLR higher than 3.95, 680 of them had a higher percentile of acute myocardial infarction (48.5%) increase, previous myocardial infarction ( 7%) and cerebrovascular accident (10%), when compared to patients withNLR < 3.95. Thus, the NLR higher than 3.95 was associated with an OR of 2.5 for acute myocardial infarction and showed higher levels of C-reactive protein (mean 5.6 mg/L) and high plasma fibrinogen levels (mean 412 mg/dL). 35 Neutrophil-lymphocyte ratio in cardiovascular diseases In a meta-analysis involving ten cohorts, a higher relative risk (RR) of all-cause mortality was observed, due to the elevation of the NLR levels when compared with low levels (RR = 2.33), as well as of cardiovascular events in patients submitted to angiography or cardiac vascularization (RR = 1.89). 3 In an observational cohort containing 2,833 patients hospitalized with acute coronary syndromes, it was detected that NLR elevations are associated with higher chances of in-hospital mortality (OR = 2.04). 26 In decompensated heart failure, of 1,212 individuals, patients with a higher tertile of NLR, showing a mean of 9.6, had an increase in themortality rate during an average follow-up of 26 months. Nevertheless, the highest tertile of NLR was associated with older age, systemic arterial hypertension, diabetes mellitus, history of coronary artery disease and arterial fibrillation. In the blood sample analyses, the highest NLR tertile was associated with the increase in B-type natriuretic peptide, urea, serum creatinine and hemoglobin levels. Consequently, the chest x-ray examination showed that the highest tertile of the NLR was associated with a higher incidence of cardiomegaly, pleural effusion and interstitial edema. 36 When analyzing a cohort of 3,005 patients for 3 years, it was evident that NLR values higher than 3 are associated with high chances of fatal coronary artery disease (OR= 2.45), aswell aswith the rate ofmajor cardiovascular events (Hazard Ratio - HR = 1.55). 29 Considering the NLR and the presence of troponin in peripheral blood in the analysis of 244 patients with chest pain treated at the emergency department, a high correlation was found between high NLR and high plasma troponin levels when acute myocardial infarction was confirmed. In those cases in which troponin was positive, the mean NLR was 5.49. On the other hand, negative troponin results showed a mean a NLR of 2.40. 32 A meta-analysis of 21 studies, including more than 34,000 patients, showed that neutrophilia causes NLR imbalance, favoring the development of cardiovascular