Drug-eluting Stenting Versus Medical Treatment for Extracranial Vertebral Artery Stenosis

Inclusion Criteria:

1. Age ≥ 18 years.
2. Extracranial vertebral artery (V1-2 segments) has 70% to 99% stenosis (NASCET criteriaby angiography), and the diameter of the target vessel ≥ 2.5mm.
3. History of clinical symptoms associated with target vessels within 3 months beforerandomization, including ischemic stroke (modified Rankin Scale, mRS score ≤ 3) ortransient ischemic attack (TIA).
4. With more than two atherosclerotic risk factors such as, hypertension, hyperlipidemia,diabetes, smoking, drinking, obesity, or obstructive sleep apnea (following the 2021AHA/ASA guidelines).
5. mRS score ≤ 3.
6. Patients or their guardians voluntarily participate of the study and sign the consentform.

Exclusion Criteria:

1. Vertebral artery stenosis caused by non-atherosclerotic lesions, including arterialdissection, Moyamoya disease, vasculitis disease, radiation-induced vascular disease,fibromuscular dysplasia, etc.
2. Tandem extracranial or intracranial severe stenosis or occlusion of the target vessel.
3. History of open surgery or endovascular treatment of the target vessel.
4. Other cerebrovascular diseases that require one-stage open surgery or endovasculartherapies.
5. Open surgery or endovascular treatment for other cerebrovascular diseases within 1month.
6. Patients in whom vertebral anatomy was felt to be technically not feasible forvertebral artery stenting (e.g. access problems).
7. The contralateral vertebral artery and basilar artery have lesions that may be relatedto the symptoms, and the investigators cannot confirm that the target vessel is theresponsible vessel for the symptoms (For example, the ostium of bilateral vertebralartery is severely narrowing, and the diameter of vertebral artery is equal, unable todetermine the dominant vertebral artery).
8. Known allergy or contraindication to iodinated contrast media and sirolimus.
9. History of acute ischemic stroke within 7 days.
10. History of intracranial hemorrhage, subarachnoid hemorrhage, subdural hemorrhage, orextradural hemorrhage within 6 weeks.
11. Cardioembolic strokes as evident by prior history of strokes in other territories ormulti-territory strokes in the presence of risk factors known to be associated withcardiogenic embolism (e.g. atrial fibrillation, left ventricular thrombus or historyof myocardial infarction within 6 weeks, etc.).
12. Coagulation dysfunction or hemorrhagic tendency (e.g. INR > 1.5 and/or platelet count < 100×10^9/L).
13. Cannot complete the follow-up due to severe diseases (e.g. serious infections, severechronic obstructive pulmonary disease, malignancy, dementia, mental illness,uncontrolled server hypertension or diabetes).
14. Women who are pregnant or lactating.
15. According to the judgement of the investigator, other situations, influencing thesafety and efficacy evaluation, which make the patient not suitable for enrollment.