Inclusion Criteria:  Patients with carotid stenosis who had a history of radiotherapy for head and neck cancer. (The median interval between the completion of radiation therapy and development of carotid artery stenosis detected on imaging (or vascular intervention) was no less than 1 years to avoid non-related situations. The target area of the radiotherapy included at least the ipsilateral neck, including part of the carotid system. The internal carotid stenosis was confirmed by angiography, Duplex, 3D angio-CTA or angio-MRI, and stenosis was defined as > 50% based on North American Symptomatic Carotid Endarterectomy Trial criteria), with or without symptom. Patients with a transient ischaemic attack (TIA) or stroke within 6 months were defined as symptomatic. TIA was defined as a transient episode of neurological dysfunction (focal weakness/ language disturbance/transient monocular blindness/ requiring assistance to walk) caused by focal brain or retinal ischemia that lasts for at least 10 min but resolves within 24 h.)  Exclusion Criteria:  The patients treated for restenosis. Intracranial arteriovenous malformation or aneurysm Severe stenosis or occlusion of the ipsilateral intracranial artery Unstable angina, myocardial infarction (MI), or congestive heart failure in the last 6 months Uncorrectable coagulation abnormalities Uncontrolled diabetes mellitus defined as glucose > 300 mg/dL (16.67 mmol/L) Pregnant or in the perinatal period Severe concomitant disease with poor prognosis (life expectancy < 2 years) Intolerance or allergies to any of the study medications, such as aspirin or clopidogrel