Methods: All consecutive patients 1) with internal carotid artery stenosis >70%, 2) indicated to CAS, 3) with signed informed consent were enrolled to the prospective study during 16 months. All patients used dual antiplatelet therapy (acetylsalicylic acid [ASA] 100 mg + clopidogrel 75 mg per day) at least 7 days before CAS. Neurological examination and brain magnetic resonance imaging (MRI) were performed before and 24 hours after CAS in all patients. Venous blood samples were collected within 24 hours before CAS in all patients: hematology + reticulocytes, coagulation markers (PT, APTT, INR, Fbg, Clauss), vWF antigen, PAI-1 activity, PAI-1 polymorphism 4G/g, Multiplate (ASA and clopidogrel resistance test). Blood samples for the assessment of anti Xa activity were collected during CAS. T-test was used for statistical evaluation.