Comparison of NFL and GFAP levels in patient groups with symptomatic and asymptomatic internal carotid artery stenosis

Cerebrovascular diseases are the second leading cause of death worldwide after cardiovascular diseases, and carotid artery stenosis accounts for a significant proportion of ischemic strokes. In recent years, research on the use of biomarkers in the clinical classification of these patients has increased. In this study, serum levels of Glial Fibrillary Acidic Protein (GFAP) and Neurofilament Light Chain (NFL) were investigated in patients with symptomatic and asymptomatic carotid artery stenosis, and their associations with stenosis severity and risk factors were analyzed, with a particular focus on findings in the asymptomatic group. The study included symptomatic and asymptomatic carotid stenosis patients as well as a control group. Demographic data, clinical features, and risk factors (such as hypertension and diabetes) were recorded; serum GFAP and NFL levels were measured using the ELISA method, and stenosis severity was assessed through imaging techniques. Data were analyzed statistically. GFAP and NFL levels were significantly higher in the symptomatic group compared to the asymptomatic group. However, in the asymptomatic group, these biomarkers were also significantly elevated compared to the control group. Within the asymptomatic group, increasing stenosis severity was associated with a significant rise in NFL levels. Although no marked differences in GFAP levels were observed among subgroups, noteworthy associations with risk factors were identified. Both symptomatic and asymptomatic groups showed a significantly higher prevalence of hypertension and diabetes compared to controls, underscoring their critical role in the development of carotid stenosis. GFAP and NFL were found to reflect the clinical severity and symptomatic status of carotid stenosis. Importantly, this study also revealed that asymptomatic patients exhibit elevated biomarker levels and are influenced by risk factors. These findings highlight that asymptomatic patients should not be considered "low-risk," emphasize the importance of strict control of hypertension and diabetes, and suggest that such patients require close monitoring for stroke risk and a re-evaluation of intervention thresholds for carotid stenosis. Keywords: Asymptomatic carotid stenosis, Symptomatic carotid stenosis, GFAP, NFL, hypertension, diabetes, biomarker, stroke