Background: Severe carotid artery stenosis is accompanied by increased risk for cognitive impairment. A member of the neurotrophin family; BDNF is expressed in human and other mammalian brains. It plays an important role in the working memory of the prefrontal cortex. So far, the effect of carotid reperfusion by carotid artery stenting (CAS) and its effect on brain level of BDNF as a biomarker for brain neural palsticity is not studied well. So,this work aimed to analyze the impact of carotid revascularization through CAS on cognition and its effect on neuroplasticity in patients with carotid stenosis 70- 99%