We performed a systematic review and meta-analysis of the association between high-grade carotid stenosis and cognitive impairment by comparing patients with and without high-grade carotid stenosis.

Cognitive impairment is a recognized manifestation of carotid atherosclerotic disease, but whether high-grade carotid stenosis independently contributes to cognitive decline remains uncertain.

A systematic search of PubMed, Web of Science, and Scopus was conducted from inception to July 11, 2025. Studies comparing cognitive function between patients with and without high-grade carotid stenosis were included. The primary outcome was cognition (continuous or dichotomous). For continuous outcomes, only studies that assessed cognition using the Mini-Mental State Examination (MMSE) were analyzed. For dichotomous outcomes (cognitively impaired, as defined per study), studies reporting the risk of cognitive impairment by carotid stenosis were included. Continuous outcomes were pooled as mean difference (MD, calculated as the difference in MMSE scores between high-grade and non–high-grade groups), and dichotomous outcomes as risk ratio (RR), both with 95% confidence intervals (CIs), using a random-effects model. Heterogeneity was assessed using the I² statistic.

Twelve studies (288 participants with high-grade and 602 with non–high-grade stenosis) assessed cognition using MMSE were included in continuous analysis. Pooled results demonstrated significantly lower MMSE scores among patients with high-grade carotid stenosis (MD = −1.45; 95% CI, −2.20 to −0.70; p = 0.0002; I² = 91%). Five studies (963 participants with high-grade and 2,126 with non–high-grade stenosis) reported cognitive impairment as a dichotomous outcome. Pooled analysis showed a significantly higher risk of cognitive impairment in patients with high-grade stenosis (RR = 2.69; 95% CI, 1.23–5.86; p = 0.01; I² = 90%).

Our meta-analysis showed that patients with high-grade carotid stenosis had 2.7-fold increased risk of cognitive impairment compared to those without high-grade carotid stenosis. Future intervention trials studies focusing on the effect of carotid stenosis on cognition are needed.