A Prospective, Experimental, Multicenter, Open-label, Randomized, Controlled Trial of 3-month Dual Antiplatelet Therapy Followed by Ticagrelor Versus 6-month Dual Antiplatelet Therapy Followed by Ticagrelor After Implanting Bridge

Inclusion Criteria: * Patients who are suitable for Bridge implantation * Symptomatic vertebral artery stenosis with a history of posterior circulation-related ischaemic stroke or TIA despite the use of at least one antithrombotic medications and intervention for risk factors * Responsible vertebral artery stenosis (≥70% stenosis, measured by the NASCET method ) confirmed by DSA imaging * The patient and/or his/her authorised person understands the purpose of the study, agrees to participate in the study and signs the informed consent form Exclusion Criteria: * mRS≥3 * Presence of tandem stenotic lesions in the target lesion areaor combined basilar artery stenosis Presence of ≥2 stenotic cerebrovascular lesions requiring concurrent intervention The presence of severe tortuosity or calcification of the target vessel, or the presence of extensive abnormal vascular structural variants that are difficult for catheters or stents to pass or cannot be implanted * Lesions or stenosis that is too large and beyond the specification of the stent * Non-atherosclerotic stenosis such as atrial fibrillation, vasculitis stenosis, arterial entrapment, smoky disease, active phase of arteritis, or unknown cause * Contraindication to heparin, aspirin, tegretol, clopidogrel, or other antiplatelet drugs, and those who cannot tolerate anticoagulant and antiplatelet drug therapy * Have had intracranial haemorrhage within 3 months * Had a myocardial infarction or large cerebral infarction within 2 weeks * Accompanied by other intracranial disease such as aneurysm, arteriovenous malformation, intracranial tumour, intracranial infection, etc * Presence of active bleeding or extremely dangerous risk of haemorrhage (e.g. active peptic ulcer disease, gastrointestinal lesions with bleeding risk, malignant tumours with bleeding risk, etc.) * Severe cardiac, hepatic, splenic, pulmonary, or renal impairment, or allergy or intolerance to contrast media, rapamycin (Rapamycin) and its derivatives, cobalt-based alloys, or polylactic acid