IF01 - Posterior cerebral artery perfusion is associated with cognitive prognosis after endarterectomy in patients with asymptomatic severe carotid stenosis.

Objectives: Severe carotid stenosis patients with declined baseline cognition has been reported in the CREST-2, and the question of whether cognition can be improved after carotid endarterectomy (CEA) remains unanswered. Alterations in cerebral blood flow are the direct physiological changes after CEA. This study investigated the relationship between cerebral blood perfusion and cognitive function after CEA in patients with severe asymptomatic carotid artery stenosis, with the aim of identifying target populations that may benefit from improved cognition after CEA.

Methods: We are conducting a prospective observational cohort study. Patients with unilateral, severe, asymptomatic carotid stenosis were included. Computerized tomography cerebral perfusion (CTP), cognitive tests, and quantitative electroencephalogram (qEEG) analysis were performed preoperatively and 6 months postoperatively (Fig 1). Regions of interest (ROI) were selected based on the blood supply areas of the anterior, middle, and posterior cerebral arteries. Using the contralateral hemisphere as a reference, we determined preoperative impaired perfusion as well as the postoperative improvement status of each region on the severe stenosis side, and compared the cognitive tests scores and qEEG characteristics of patients with different perfusion status.

Results: A total of 52 individuals were included in the analysis to date (Fig 1), with 75.0% male patients and a mean age of 60.4± 7.1 years (Table I). Preoperatively, 61.5%, 55.4%, and 30.4% of patients exhibited impaired perfusion in the anterior, middle, and posterior artery supply ROIs, respectively. Among them, patients with impaired posterior perfusion demonstrated significantly poorer baseline cognitive scores (Table II). Additionally, individuals with impaired posterior circulation perfusion exhibited a characteristic reduction in ipsilateral occipital γ-band activity (Fig 2).
Six months postoperatively, there was improvement in perfusion for 56.7%, 45.4%, and 21.8% of cases in the anterior, middle, and posterior artery supply regions, respectively. Patients with improved posterior perfusion showed a significant improvement in cognitive scores, particularly in memory test (RAVLT Z score change: 0.67 vs. -0.14, p=0.002) (Table III). Moreover, postoperative occipital γ-band activity was restored to the symmetrical levels of the contralateral hemisphere. Clinical analysis showed severe stenosis of the vertebral/basilar arteries was higher in patients with posterior perfusion impairment (78.6% vs. 28.9%, p=0.002) and was significantly associated with improved cognitive tests scores after CEA (β coefficient=1.36, 95% CI: 0.33-2.38, p=0.01).

Conclusions: Severe asymptomatic carotid stenosis patients with impaired posterior perfusion may be the population that benefits from cognitive function after CEA. The presence of concomitant vertebrobasilar artery stenosis and lower γ-band activity may serve as predictive factors.