Objective: To compare the effect on cognition of carotid artery stenting (CAS) and carotid endarterectomy (CEA) for symptomatic carotid artery stenosis.
Methods: Patients randomized to CAS or CEA in the International Carotid Stenting Study (ICSS; ISRCTN25337470) at 2 participating centers underwent detailed neuropsychological examinations (NPE) before and 6 months after revascularization. Ischemic brain lesions were assessed with diffusion-weighted imaging before and within 3 days after revascularization. Cognitive test results were standardized into z scores, from which a cognitive sumscore was calculated. The primary outcome was the change in cognitive sumscore between baseline and follow-up.
Results: Of the 1,713 patients included in ICSS, 177 were enrolled in the 2 centers during the substudy period, of whom 140 had an NPE at baseline and 120 at follow-up. One patient with an unreliable baseline NPE was excluded. CAS was associated with a larger decrease in cognition than CEA, but the between-group difference was not statistically significant: -0.17 (95% CI -0.38 to 0.03; p = 0.092). Eighty-nine patients had a pretreatment MRI and 64 within 3 days after revascularization. New ischemic lesions were found twice as often after CAS than after CEA (relative risk 2.1; 95% CI 1.0 to 4.4; p = 0.041).
Conclusions: Differences between CAS and CEA in effect on cognition were not statistically significant, despite a substantially higher rate of new ischemic lesions after CAS than after CEA.
Classification of evidence: This study provides Class III evidence that any difference between the effects of CAS and CEA on cognition at 6 months after revascularization is small.