Cognitive Function After Carotid Endarterectomy: Early Decline and Later Recovery

To prospectively study neurocognitive performance following carotid endarterectomy (CEA) in various follow-up periods, taking into account the potential confounding factors.

Thirty-six patients with carotid artery stenosis received CEA (group A). Thirty-one patients underwent surgery for femoropopliteal occlusive disease served as controls (group B). Neuropsychological testing and brain magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) was repeated preoperatively, within 3 days and at 3 months after surgery.

No patient had DWI evidence of procedure-related cerebral ischemia. Preoperative baseline scores of groups A and B were not statistically different in mini mental state examination (MMSE) or clock drawing task (CDT) score. MMSE and CDT scores were significantly reduced for patients in group A (p < 0.01) within 3 days after CEA. Differences of MMSE score (p=0.48) and CDT score (p=0.26) between baseline and 3 months after surgery in group A were not statistically significant. No statistically significant change of MMSE score and CDT score in group B was observed at 3 days and 3 months after the surgery. Degree of internal carotid artery (ICA) stenosis (p=0.029) and duration of ICA clamping (p=0.031) were significantly higher in patients with cognitive impairment immediately after CEA than in those without that.

Our study demonstrated cognitive decline for the patients with unilateral carotid stenosis at early stage after CEA and a restorative effect at 3 months after CEA. Postoperative early cognitive impairment might be associated with intraoperative temporary hypoperfusion and postoperative hyperperfusion, not the microembolic event.