The Efficacy and Safety of Intracranial Stent (Tonbridge) in Endovascular Treatment of Symptomatic Intracranial Atherosclerotic Stenosis

Inclusion Criteria: * Age 18-75; * Subjects with symptomatic intracranial atherosclerotic stenosis who do not respond to antiplatelet therapy or have poor compensation of collateral circulation and hypoperfusion in the offending vessel blood supply; * The last onset time of TIA is not limited or the last onset of ischemic stroke is more than 2 weeks; * The lesion is confirmed to be located in intracranial large arteries, including intracranial segment of the internal carotid artery, middle cerebral artery, intracranial segment of vertebral artery and the basilar artery; * Target vessel diameter≥2.0mm and ≤4.5mm, lesion length ≤33mm; * Stenosis degree of intracranial arteries≥70% and ≤99% measured by intracranial angiography (WASID method); * Intracranial artery stenosis which requiring interventional treatment is a single lesion; * Subjects have at least 1 atherosclerotic plaque risk factor including hypertension, diabetes mellitus, hyperlipidemia, hyperhomocysteinemia, coronary heart disease, obesity, and smoking history; * mRS≤2 before enrollment; * Voluntarily participate in this study and sign the informed consent form, can complete examinations and follow-ups in accordance with the requirements of the protocol during the clinical trial. Exclusion Criteria: * Intracranial arterial stenosis caused by non-atherosclerotic lesions: such as arterial dissection, moyamoya disease, vasculitis, active arteritis, etc.; * Preoperative MRI shows only perforator infarction in the target lesion; * Preoperative CT or MRI indicates the presence of post-infarct hemorrhagic transformation in the target vascular, or a history of subarachnoid, subdural, and epidural hemorrhage within 30 days before procedure, or the presence of untreated chronic subdural hematoma (≥5mm); * Severe calcification of target vessels; or target vessel tortuosity or other reasons will make experimental device difficult to reach the target lesion position; * There is more than 70% stenosis in the distal intracranial large vessels or proximal intracranial and extracranial large vessels of the target vessels, and the presence of unidentified responsible lesions; * Subjects have a major surgery within 30 days before procedure or intend to be hospitalized for other procedure within 6 months after procedure; * Intracranial tumors or intracranial arteriovenous malformations, or distal and proximal target vessels combined with aneurysms; * The target lesion has a history of stent implantation; * It is suspected that there is severe allergy or contraindication to aspirin, clopidogrel, heparin, contrast media, nitinol and other drugs and devices related to endovascular therapy; * There is an underlying source of cardiac thrombus, such as atrial fibrillation, left ventricular thrombus, myocardial infarction within 30 days; * Subjects with an INR \> 1.5 or the presence of nonmodifiable bleeding factors; * Medically uncontrolled severe hypertension (systolic blood pressure \> 180 mmHg or diastolic blood pressure \> 110 mmHg); * Severe comorbid conditions or unstable conditions, such as severe heart failure, pulmonary failure, or renal failure (serum creatinine \>3.0 mg/dL (264μmol/L)), severe liver insufficiency (ALT or AST \>3 times normal), and malignancy; * Life expectancy is less than two years; * Women who are pregnant or breastfeeding; * Subjects unable to complete follow-up due to cognitive impairment, mood disorder, or mental illness; * Subjects who are enrolled in other clinical trials of drugs/devices and have not yet met the primary endpoint; * Other circumstances which investigators do not consider are appropriate for intracranial stent treatment.