The correlation between vulnerable carotid plaque and inflammation——an exploratory research based on Histopathology

Abstract Background Vulnerable plaques with ruptured fibrous cap were prone to produce emboli and cause distal arterial embolism. The identification of vulnerable plaque in humans before it becomes symptomatic has been elusive to date. Inflammation related ratio of leukocytes and their subtypes had been proved that they can predict cardiovascular diseases, while we aimed to explore the correlation between those and vulnerable carotid plaque. Methods Ischemic stroke patients admitted to the Department of Neurology were analyzed as study group (neurology group) from January 2019 and December 2020. Besides, patients who underwent carotid endarterectomy (CEA) during the same period were collected as control group (neurosurgery group) for compare. All patients were categorized into stable and vulnerable plaque groups based on the characteristics of plaque assessed by carotid doppler ultrasonography (CDU). The H&E staining characteristics of carotid plaque after CEA were analyzed to test the feasibility of ultrasound grouping in the study group. The inflammation-related ratio (PLR: platelet-to-lymphocyte ratio, NLR: neutrophil-to-lymphocyte ratio, MLR: monocyte-to-lymphocyte ratio) were collected to analyze. Spearman linear correlation analysis and logistic regression analysis were used to evaluate the correlation between factors and plaque vulnerability, and multivariate analysis was used to exclude confounding factors. Results In study group, comparisons of hs-CRP and NLR among the vulnerable plaque group and stable plaque group showed a statistically significant difference (p < 0.05). Multivariate logistic analysis revealed that elevated levels of NLR were independent risk factors for carotid plaque vulnerability in the study group (2.399; 1.468–3.921; p < 0.001). Incorporating the control group’s data (neurosurgery group), patients with vulnerable carotid plaques present with higher hs-CRP and lower HDL-C. Low level HDL-C would lose its protective effect on vulnerable carotid plaque (0.15; 0.023–0.958; p = 0.045). The ultrasonic and pathological characteristics of carotid plaques in the control group had strong consistency. Conclusions The inflammation reflected by the high level of hs-CRP plays a vital role in forming vulnerable carotid plaques. NLR is expected to effectively predict vulnerable carotid plaque for stroke patients at the first visit and is easier to obtain in clinical.