 Blood sample analysis: As a secondary outcome, we will analyze subjects blood sample in respect to two particular substances: S100B and neuron specific enolase. The rationale for performing proteomic studies is that past research has shown that subtle cerebral injuries after carotid endarterectomy, even in the absence of stroke, might be associated with a significant increase in serum S100B Connolly, 2001 - Neurosurgery, 2001 49 5 and also in traumatic brain injury Cotena, 2006, J Neurosurg 2006 104 6. In addition, neuron specific enolase NSE also seems to be valuable to predict brain damage in patients with brain traumatic injury Naeimi, 2006 - Brain Inj 2006 205, thus showing that these two substances might be important biomarkers to be investigated in our study. 