The effect of severe carotid occlusive disease and its surgical treatment on cognitive functions of the brain

Surgery of a high-grade carotid stenosis is evidence-based stroke prevention. Also cognitive effects are reported after carotid endarterectomy (CEA): both deterioration and improvement, the former attributed to perioperative complications and the latter often to learning effect. By imaging, brain perfusion and diffusion changes were shown in subjects with a high-grade stenosis undergoing CEA. We wanted to find out if the cognition of patients undergoing CEA display postoperative worsening or true improvement in association with findings in serial MR imaging. The patients had a poorer overall cognition than healthy matched controls. The cerebral hemisphere ipsilateral to the stenosis had higher diffusion and more sluggish perfusion leading to perfusion deficits. These asymmetries were abolished by CEA. Postoperatively, the patients showed a trend for cognitive worsening, most often attentional, but over months, the group performance improved similarly to the controls. Still, lower baseline perfusion was associated with a greater cognitive improvement, most clearly in executive functions. Consequently, despite the risk for transient decline, true cognitive benefit by CEA seems possible.