The role of carotid artery stenting and carotid endarterectomy in cognitive performance: a systematic review.

BACKGROUND AND PURPOSE Change in cognition is being increasingly recognized as an important outcome measure; however, the role of carotid revascularization on this issue remains to be determined. It is still under debate whether carotid artery stenting and carotid endarterectomy have the same influence on neuropsychological functions. SUMMARY OF REVIEW This article systematically reviews recent literature in an attempt to clarify this issue. A total of 32 papers reporting on neurocognition after carotid endarterectomy (n=25), carotid artery stenting (n=4), or carotid artery stenting versus carotid endarterectomy (n=3) were identified. The studies were different for many methodological factors, eg, sample size, type of patients and control group, statistical measure, type of test, timing of assessment, and so on. There was a lack of consensus in defining the improvement or impairment after either carotid artery stenting or carotid endarterectomy. Furthermore, there were nonuneqivocal results regarding the same domain of assessment (memory, visuomotor, attention). Based on available evidence, it is probable that carotid endarterectomy as well as carotid artery stenting do not change neuropsychological function "per se." CONCLUSIONS Assessment of cognition after carotid revascularization is probably influenced by many confounding factors such as learning effect, type of test, type of patients, and control group, which are often minimized in their importance. The role of carotid revascularization is to prevent stroke in patients with severe carotid stenosis as highlighted by previous large randomized trials. Although an effect of carotid revascularization on cognition could be missed as a consequence of underpowered studies included in this review, at this time, no prediction can be done regarding its repercussions on higher intellectual functions. Larger studies appropriately designed and powered to assess cognition after carotid revascularization might change this view.