Carotid revascularization and cognitive impairment: the neglected role of cerebral small vessel disease

Carotid atherosclerosis is a pathological process that leads to narrowing of the vessel lumen and a consequent risk of stroke. Revascularization procedures such as carotid endarterectomy (CEA) and carotid stenting aim to reduce occurrence of stroke in selected patients. Due to the proven benefit and low intraoperative risk, CEA is currently the preferred choice in candidates for carotid revascularization. However, the risk of cognitive impairment subsequent to CEA has not been fully elucidated and is unclear whether certain conditions, such as frailty, may increase this risk. There is consistent evidence that shows that frail patients have higher risk of cognitive impairment after surgical procedure. Moreover, brain pre-existing conditions may play a role in cognitive impairment after CEA. Cerebral small vessel disease (SVD) is a pathology that involves microcirculation and is detectable with computed tomography or magnetic resonance. SVD shares common vascular risk factors with carotid atherosclerosis, is a major contributor to vascular cognitive impairment and vascular dementia, and has been proposed as a marker of brain frailty. In this review, we discuss the current evidence about the link between carotid revascularization and cognitive impairment and advance the hypothesis that SVD may play a relevant role in development of cognitive impairment after carotid revascularization.