Posterior Cerebral Perfusion Associates With Cognitive Improvement After Carotid Endarterectomy in Asymptomatic Stenosis.

BACKGROUND: Patients with severe asymptomatic carotid stenosis exhibit inferior baseline cognition. Whether cognition improves after carotid endarterectomy (CEA) remains inconclusive. This study investigated the relationship between regional cerebral perfusion and cognitive function following CEA in patients with asymptomatic carotid stenosis. METHODS: In this prospective observational cohort study, patients with unilateral severe asymptomatic carotid stenosis (70%-99%) undergoing CEA were recruited. Computed tomographic perfusion, a cognitive battery, and quantitative electroencephalogram were assessed preoperatively and 6 months after CEA. Perfusion impairment was defined using regions of interest computed tomographic perfusion parameters based on the anterior, middle, and posterior cerebral artery territories. RESULTS: A total of 52 individuals were included in the analysis. Preoperatively, perfusion impairment was most prevalent in anterior cerebral artery territory regions of interest (61.2%), followed by middle (55.8%) and posterior cerebral artery (PCA; 32.4%) territories. Perfusion-impaired regions of interest associated with worse baseline cognition were primarily located in PCA territory. These patients with PCA perfusion impairment also exhibited reduced ipsilateral occipital γ-band power on quantitative electroencephalogram (P=0.024). A majority of initially impaired regions of interest showed perfusion improvement, while no significant cognitive improvement was observed at the overall cohort level. However, patients with PCA-territory perfusion improvement had better baseline-adjusted 6-month global cognitive, executive-function, and memory scores, together with restored occipital γ-band symmetry. Multivariate analysis identified concomitant vertebrobasilar stenosis and preoperative perfusion impairment in the cuneus region at the lateral ventricular plane as predictors of global cognitive improvement after CEA. CONCLUSIONS: This exploratory study suggested that patients with asymptomatic carotid stenosis with PCA territory perfusion impairment may represent a potential subgroup for cognitive improvement after CEA.