The Carotid Artery Stenting without Embolic Protection (CASWEP) trial is designed in a prospective, randomized, multi-center fashion to determine if CAS without CPD is feasible and safe in patients with symptomatic or asymptomatic severe carotid stenosis. After the exclusion criteria were applied 200 patients were divided as 100 patients in the CAS with CPD arm and 100 patients in the CAS without CPD arm. The study population includes patients with severe carotid artery stenosis referred to the to the 4 study center hospitals.