The study hypothesizes that Drug -eluting stents are more effective in preventing restenosis than Bare-metal stents after Vertebral Artery Ostium stenting

The vertebral artery ostium stenosis was one of the higher risk of the ischemia stroke in China. In the mean time ,more and more people accept revascularization. There are no prospective studies for comparison of prevention of restenosis after Drug -eluting stents and Bare-metal stents until now.

The main aim of this study is to observe the following details:

1. Late loss in lumen diameter in follow-up ≥50%
2. Death, non -fatal stroke 30 days after stent implantation associated with antiplatelet drugs
3. Death, non -fatal stroke 12 months after stent implantation associated with antiplatelet drugs

Secondary endpoint:

brain, gastrointestinal and urinary system bleeding in 12 months follow-up

Inclusion Criteria:

- symptomatic posterior circulation ischemia including monor stroke (mRS ≤2) or TIA result from the stenosis in the vertebral artery ostium.

70% to 99% stenosis of vertebral artery ostium.

Exclusion Criteria:

• etiology of stenotic lesions not atherosclerosis patients had undergone previos interventions on the vertebral artery ostium ipsilateral severe stenotic lesions in subclavian artery involved as well as vertebral artery ostium

Symptomatic status: as evidenced by TIA or non-severe stroke within the past 12 months attributed to 70% to 99% stenosis of vertebral artery ostium are eligible. Degree of stenosis: >70% and <99%; stenosis may be diagnosed by TCD, MRA, or CTA to qualify for angiogram performed as part of the study protocol, but must be confirmed by catheter angiography for enrollment in the trial. All the patients should be performed with PTAS beyond a duration of 3 weeks from the latest ischemic symptom onset. No fresh infarctions identified on MRI (indicated as high signals on DWI series) upon enrollment.Patient is willing and able to return for all follow-up visits required by the protocol Patient understands the purpose and requirements of the study, can make him/herself understood, and has signed informed consent.