IJCS | Volume 31, Nº5, September / October 2018

535 Santos & Izidoro NLR in CVD risk assessment Int J Cardiovasc Sci. 2018;31(5)532-537 Review Article disorders compatible with acute myocardial infarction, unstable angina, acute coronary syndrome, heart failure development or aggravation, cerebrovascular accident, and even increased mortality. 30 Perspectives: association of the neutrophil- lymphocyte ratio with several diseases and need for laboratory reference Heart disease pathophysiological processes are associated with the hemodynamic and inflammatory imbalance of other diseases, such as kidney and intestinal diseases. 37,38 For instance, concerning kidney diseases, the mean NLR value of 4.59 in patients submitted to hemodialysis with a diagnosis of atherosclerotic plaques was associated with greater common carotid artery intima-media thickness and higher cardiovascular mortality than patients undergoing hemodialysis but without atherosclerotic plaques, who had a mean NLR of 2.38. 39 The association between inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis and heart disease is probably due to the processes of atherosclerosis and thrombotic events, which lead to an increase in NLR. 40 The imbalance of the lipid profile caused by inflammatory bowel diseases reflects in the decrease of HDL levels and function, in addition to inducing an increase in the levels of LDL, C-reactive protein, pro- inflammatory cytokines, endotoxins, homocysteine and coagulation factors. Therefore, such organic conditions favor endothelial dysfunction, with the onset of the atheroma plaque and other cardiovascular diseases, and an increase in NLR is expected. 41 Moreover, NLR may be used as a marker of clinical follow-up in cancer cases, which involve significant changes in inflammatory responses concomitantly with the immune system. NLR as a ratio ≥ 5 being considered elevated was significantly correlated with larger tumor size in patients with advanced esophageal squamous cell carcinoma than patients with NLR < 5. 42 The NLR cutoff value ≥ 5 also reflected a lower response to Kawasaki disease therapy than patients with NLR < 5, which is associated with coronary abnormalities. 43 Furthermore, two meta-analyzes have also shown that the NLR increase is significantly associated with larger tumor size and lower overall survival in patients with cervical cancer. 44,45 TheNLRwas also considered a newprognostic marker in patients with liver cancer. 46 Due to the importance represented by recent studies regarding NLR in the prognosis for cardiovascular diseases 39,43,47-49 and its association with other inflammatory diseases, 42,44,45,50 establishing a laboratory reference specific for the NLR is promising. Differences in demographic classifications, such as classifications by age group and gender, should be considered. Conclusion The genesis of atherosclerotic processes, as well as other diseases associated with inflammatory processes, directly influence the neutrophil/lymphocyte ratio; thus, the NLR emerges as an auxiliary tool mainly in the prognosis of atherosclerosis-related cardiac disorders. The use of this ratio can help the physician to stratify patients into different categories of risk for cardiovascular disease development. It can be easily incorporated into the laboratory routine and it practically does not involve additional costs. However, it is necessary to standardize NLR cutoff points for this type of disorder, as well as in other disease processes. Author contributions Conception and design of the research and writing of the manuscript: Santos HO, Izidoro LFM; Acquisition of data and analysis and interpretation of the data: Santos HO; Critical revision of the manuscript for intellectual content: Izidoro LFM. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associated with any thesis or dissertation work.