The benefits of cerebrovascular stents are greater than the harms. Generally, after implanting stents and taking medication as prescribed by the doctor, cerebral overperfusion syndrome may occur, and cerebral vasospasm may also be caused during the procedure, leading to cerebral ischemia, and the failure to take medication on time after the procedure may result in the formation of small embolus or re-stenosis in the stent, secondary to cerebral infarction, and so on. 1. Cerebral over-perfusion syndrome: It is a syndrome that occurs when the cerebral blood flow increases exponentially beyond the automatic regulation of cerebral blood vessels after the cerebral vascular stenosis is lifted. Headache, vomiting, euphoria, epilepsy, fever and focal neurological dysfunction may occur. 2. Cerebral ischemia secondary to surgery: due to the stimulation of blood vessels during surgery, causing vasospasm and contraction, secondary to cerebral ischemia, which can lead to cerebral infarction in severe cases, and may result in hemiparesis, aphasia, and so on. 3. Post-operative cerebral infarction: Since the blood flow of patients with cerebral thrombosis is slow and viscous, it is easier to form thrombus, and after implantation of stent, it is easy to form embolus in the site of stent or restenosis in the stent, which may cause cerebral infarction, so the patients should insist on taking anti-tethering drugs (aspirin, clopidogrel) as prescribed by the doctor to prevent the formation of thrombus, and they should be rechecked regularly in the hospital after the operation.