Relationship of Neutrophil-to-Lymphocyte Ratio with Carotid Plaque Vulnerability and Occurrence of Vulnerable Carotid Plaque in Patients with Acute Ischemic Stroke

Abstract

Background. Carotid plaque is an undefined risk factor in ischemic stroke and is driven by inflammation. Mounting evidence suggests that neutrophil-to-lymphocyte ratio (NLR) is crucial not only for cerebrovascular events but also in atherosclerosis progression. Here, we aimed to explore the association between the admission NLR and carotid plaque vulnerability as well as the occurrence of vulnerable carotid plaque detected by carotid ultrasonography in patients with acute ischemic stroke (AIS) among Chinese. Methods. We conducted a retrospective study composed of 588 patients with AIS and 309 healthy controls free of carotid plaque in the Department of Neurology in The Second Hospital of Lanzhou University from March 2014 to February 2015. All patients were classified as nonplaque, stable plaque, and vulnerable plaque groups on the basis of carotid ultrasonography results. The baseline information was collected and compared among the four different groups. The correlation between variables and carotid plaque vulnerability was tested by Spearman linear correlation analysis. To identify the independent predictors for vulnerable carotid plaque, univariate and multivariate logistic regression analysis was performed. Results. The comparisons of age, sex proportion, history of hypertension, diabetes, and smoking, the levels of HDL-C, Lp(a), BMI, SBP, DBP, Fib, CRP, leukocyte, and NLR among the four groups showed a statistically significant difference ( $P<0.05$ ); in particular, the NLR was significantly higher in the vulnerable plaque group as compared to the control ( $P=0.043$ ), nonplaque ( $P=0.022$ ), and stable plaque groups ( $P=0.015$ ). The Spearman correlation analysis presented a positive correlation between carotid plaque vulnerability and age ( $r=0.302$ ; $P<0.001$ ), SBP ( $r=0.163$ ; $P<0.001$ ), and NLR ( $r=0.087$ ; $P=0.034$ ), while the lymphocyte was negatively related to the carotid plaque vulnerability ( $r=-0.089$ ; $P=0.030$ ). The multivariate logistic regression analysis adjusted for confounding factors revealed that age (odds ratio [OR], 1.042; 95% confidence interval [CI], 1.025-1.060; $P<0.001$ ), male gender (OR, 2.005; 95% CI, 1.394-2.884; $P<0.001$ ), diabetes (OR, 1.481; 95% CI, 1.021-2.149; $P=0.039$ ), SBP (OR, 1.012; 95% CI, 1.003-1.021; $P=0.010$ ), and NLR (OR, 1.098; 95% CI, 1.018-1.184; $P=0.015$ ) are independent predictors of vulnerable carotid plaque in patients with AIS. Conclusion. The admission NLR is a novel and meaningful biomarker that can be used in predicting carotid plaque vulnerability and the presence of vulnerable carotid plaque assessed by carotid ultrasonography in patients with AIS among Chinese.