Inclusion Criteria:  Evidence of intracranial large severe stenosis or occlusive artery in angiography. Absence of intracranial hemorrhage. Premorbid mRS score is ≤ 3. Recurrent stroke in the target territory during the medical treatment for ischemic stroke prevention.  Exclusion Criteria:  Tandem lesion. Loss to follow-up after discharge. A severe or fatal combined illness before acute ischemic stroke. Progressive neurologic deficit within 7 days after acute ischemic stroke. Large middle cerebral artery infarct within 30 days after acute ischemic stroke.