Cognitive Function After Carotid Endarterectomy: Early Decline and Later Recovery

Abstract

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

Material and methods: 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.

Results: 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.

Conclusion: 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.