Prognostic Utility of Neutrophil-to-Lymphocyte Ratio on Adverse Clinical Outcomes in Patients with Severe Calcific Aortic Stenosis

Background Inflammation is an important factor in the pathogenesis of calcific aortic stenosis (AS). We aimed to evaluate the association between an inflammatory marker, neutrophil-to-lymphocyte ratio (NLR) and major adverse cardiovascular events (MACE) in patients with severe calcific AS. Methods A total of 336 patients with isolated severe calcific AS newly diagnosed between 2010 and 2015 were enrolled in this study. Using Cox proportional hazards (PH) regression models, we investigated the prognostic value of NLR adjusted for baseline covariates including logistic European System for Cardiac Operative Risk Evaluation score (EuroSCORE-I) and undergoing aortic valve replacement (AVR). We also evaluated the clinical relevance of NLR risk groups (divided into low, intermediate, high risk) as categorized by NLR cutoff values. MACE was defined as a composite of all-cause mortality, cardiac death and non-fatal myocardial infarction during the follow-up period. Results The inflammatory marker NLR was an independent prognostic factor most significantly associated with MACE [hazard ratio (HR), 1.06; 95% confidence interval (CI), 1.04-1.09; pvalue < 0.001]. The goodness-of-fit and discriminability of the model including EuroSCOREI and AVR (loglikelihood difference, 15.49; p-value < 0.001; c-index difference, 0.035; pvalue = 0.03) were significantly improved when NLR was incorporated into the model. The estimated Kaplan-Meier survival rates at 5 years for the NLR risk groups were 84.6% for the low risk group (NLR <= 2), 67.7% for the intermediate risk group ( 2 < NLR <= 9), and 42.6% for the high risk group ( NLR > 9), respectively. Conclusion The findings of the present study demonstrate the potential utility of NLR in risk stratification of patients with severe calcific AS.