The purpose is to test whether a short-term, high-dose atorvastatin treatment (80mg once a daily (QD) from 3 days before to 3 days after CAS, then 20 mg QD until 30 days after CAS) is superior to conventional-dose atorvastatin treatment (20 mg QD from 3 days before to 30 days after CAS), in terms of efficacy for prevention of periprocedural ischemic brain damage in Chinese patients undergoing CAS.

Chinese patients with carotid stenosis scheduled for selective CAS will be randomized into two groups. The High-dose Atorvastatin group will receive Atorvastatin 80 mg QD from 3 days before to 3 days after CAS, then 20 mg QD until 30 days after CAS, while the Conventional-dose Atorvastatin group will receive Atorvastatin 20 mg QD from 3 days before to 30 days after CAS. All patients will receive cerebral diffusion-weighted (DW)-MRI within 7 days before CAS. Then, they will also receive repeated DW-MRI within 5 days after CAS. Efficacy for prevention of periprocedural ischemic brain damage of the two different Atorvastatin treatments will be compared, in terms of periprocedural incidence of transient ischemic attack (TIA)/ ischaemic stroke or new ischemic lesions on cerebral DW-MRI.

Inclusion Criteria:

• ≥ 50% stenosis of internal carotid artery in symptomatic patients; or ≥ 70% stenosis of internal carotid artery in asymptomatic patients
• received statin therapy for ≥ 2weeks before inclusion

Exclusion Criteria:

• nonatherosclerotic carotid disease (dissection, radiation-induced stenosis)
• received endovascular procedure within 30 days before inclusion
• CAS during the procedure of urgent endovascular therapy for acute ischaemic stroke
• need for oral anticoagulant therapy
• high risk of bleeding or contraindications to antiplatelet therapy (eg: platelet count <70 X 109/L)
• active hepatic disease or hepatic dysfunction, or aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 1.5 upper normal limit
• myopathy or increased creatine kinase (CK) > 2 upper normal limit
• renal failure with serum creatinine (Scr) > 3 mg/dl or 264μmol/L
• unable to undergo MRI because of claustrophobia or pacemaker
• pregnancy, lactation, or child bearing potential women without any effective contraception