Longitudinal Evaluation of Neurobehavioral Outcomes After Carotid Revascularization

Abstract

Carotid revascularization, including carotid endarterectomy (CEA) and carotid angioplasty and stenting (CAS), is performed for stroke risk reduction but may also impact cognitive function. Cognitive outcomes observed after carotid revascularization have been inconsistent, and mechanistic relationships with procedural factors are poorly understood. To further explore associations between carotid revascularization and cognitive outcomes, a prospective longitudinal evaluation was conducted of patients undergoing elective CEA or CAS for hemodynamically significant carotid stenosis. Patients undergoing primary carotid artery revascularization for hemodynamically significant stenosis were evaluated with neurologic and neuropsychological testing at baseline and at 1 and 6 months after revascularization. A subgroup of patients was also studied with baseline and postoperative magnetic resonance imaging (MRI). Outcomes included neurologic or neuropsychological deficits and imaging findings (including quantitative assessment of cerebral blood flow). Sixteen patients underwent carotid revascularization with both preoperative and postoperative neurologic and neuropsychological testing; preoperative and postoperative MRIs were also performed on eight patients. Five of 16 treated carotid lesions (31%) were considered symptomatic, and severity of carotid stenosis was 60-79% for 6 of 16 lesions and 80% or more in all others. A single perioperative neurologic deficit was identified; all other patients (15/16) had no abnormalities detected by neurologic examination. Neuropsychological testing identified new postoperative deficits in 3 patients (19%), among whom 2 had a normal neurologic examination at all time points, whereas 1 had clinical evidence of stroke. Quantitative analysis of mean cerebral blood flow revealed postrevascularization increases for both gray matter (48.6 ± 13.9 mL per 100 g/min vs 75.3 ± 70.8 mL per 100 g/min) and white matter (31.8 ± 10.6 mL per 100 g/min vs 55.2 ± 30.1 mL per 100 g/min)(P = 0.04). New postoperative MRI foci of restricted diffusion were identified in 2 patients, both of whom had no neurologic or neuropsychological deficit. Among patients with postoperative neuropsychological deficits, MRI revealed globally increased cerebral perfusion without new postoperative abnormalities in 2 of 3. The relationship between carotid revascularization and cognitive function is complex, and cognitive deficits may occur in the presence of increased cerebral perfusion without detectable embolization.