To compare the effect on cognition of carotid artery stenting (CAS) and carotid endarterectomy (CEA) for symptomatic carotid artery stenosis.
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.
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).
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.
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