1. Main causes of ischemic cerebrovascular disease Ischemic stroke accounts for the majority of cerebrovascular disease events, about 80%. Among the many risk factors (hypertension, hyperlipidemia, diabetes mellitus, smoking, etc.), arterial stenosis is an independent risk factor for ischemic stroke. Stenosis (mainly atherosclerotic stenosis) of intracranial and extracranial blood vessels (intracranial blood vessels and extracranial segments of carotid and vertebral arteries) is the main vasculopathological factor of ischemic stroke, and about 70% of ischemic stroke patients have stenosis of intracranial and extracranial arteries. 2.What is cerebral angiography? Cerebral angiography is a routine, well-established diagnostic method that uses X-rays to explore the cause of stroke, the location of aneurysms and the choice of treatment. The method of cerebral angiography is to make a puncture at the root of the patient’s thigh, inject the contrast agent into the artery through a thin and soft catheter, and take pictures continuously to record the process of angiography, so that the vascular image of the brain is clearly displayed on the TV screen and X-ray film, which is used by the doctor to determine whether there is any lesion in the cerebral arteries and to make an accurate diagnosis and choice of treatment. Cerebrovascular disease treatment methods Cerebrovascular disease treatment mainly consists of drug treatment, surgical treatment and interventional therapy. Among the three methods, the effect of drug treatment is not ideal, surgical operation (carotid endarterectomy and intracranial and extracranial vascular bridging) treatment is effective, but relatively traumatic, requiring general anesthesia, sometimes blocking the cerebral blood flow during the operation, and then can not be repeated when the stenosis occurs, and this kind of operation is not common enough in China. The complications of carotid endarterectomy are about 60%, and the restenosis rate is 7~15% or even higher, therefore, the surgical treatment has many defects, such as traumatization, strict contraindications, etc., and the efficacy of the treatment has a strong operator dependence. Endovascular dilatation and stenting for stenosis of cervical blood vessels (including carotid artery and vertebral artery) with neurointerventional therapy has the advantages of high surgical success rate, minimal trauma, wide indications, low restenosis (or recurrence) rate (about 5%), and repeatable, and endovascular dilatation and stenting not only increases cerebral blood flow and improves cerebral ischemia through the direct treatment of stenosis but also prevents or reduces stroke recurrence. It also prevents or reduces the recurrence of stroke. Interventional therapy, as a new treatment method, is the safest and least invasive procedure by balloon dilatation and stenting of the arteries in the brain with reliable efficacy. 4.What is cerebral stenting? After cerebral angiography confirms the diagnosis of severe narrowing of cerebral blood vessels, cerebral stenting is performed according to the situation. Under X-ray fluoroscopy, the balloon is sent to the diseased blood vessels, and the balloon is expanded by pressurizing and filling the balloon, thus changing the blood supply of the blood vessels and relieving the symptoms. After the lesion is expanded, a stent is needed to hold the lesion open permanently. The stent is implanted to reduce the collapse of the vessel after plaque rupture, acute occlusion, increase the safety of the procedure, and reduce restenosis. 5.Why do patients with ischemic cerebrovascular disease need cerebral angiography? Vascular stenosis is the main cause of ischemic cerebrovascular disease. Intracranial and extracranial vascular stenosis can directly cause cerebral ischemia, secondary thrombosis resulting in cerebral ischemia, and cerebral ischemia can be caused by thrombus or atherosclerotic plaques at the stenosis falling off and blocking the cerebral blood vessels. Therefore, cerebral angiography is an important diagnostic tool to clarify the cause of ischemic cerebrovascular disease. Only when the location and nature of the vascular lesions are clear can the source of the disease be targeted for fundamental treatment. 6.What kind of stenosis needs stenting? Endovascular stenting is currently recognized as the most effective treatment for ischemic cerebrovascular disease caused by arterial stenosis. It is generally believed that if arterial stenosis is ≥70%, regardless of whether there are symptoms or not, endovascular stenting is required to eliminate the stenosis and prevent the onset of stroke; if stenosis is <70%, as long as there are symptoms caused by the vascular lesion, endovascular stenting should be performed. If there is no symptom, endovascular stenting can be performed under close observation; if the stenosis is <30% and there is ulcerative plaque, endovascular stenting should be performed in a timely manner regardless of whether there are symptoms or not. 7.What is the mechanism of endovascular stenting? The mechanism of endovascular stenting for ischemic cerebrovascular disease has the following three aspects: (1) Due to arterial stenosis, the cerebral blood supply is insufficient, which puts a part of brain cells in ischemia and hypoxia, adjacent to the edge of death; once there is a violent fluctuation of blood pressure or an accidental blow that causes a further decrease in the cerebral blood flow, this part of the cells will undergo necrosis, and once the vascular stenosis is eliminated and the cerebral blood flow is increased, this part of the cells can be necrotic. Once the stenosis is eliminated and the cerebral blood flow increases, the function of this part of the cells will be saved; (2) Atherosclerotic plaques on the blood vessel wall can be dislodged when they are unstable and reach the distal end of the vessel along with the blood flow, which will cause occlusion of the distal vessel. After stent placement, the unstable plaque can be pressed down by the compression effect of stent, thus preventing the dislodgement; (3) For ulcerative plaque, due to the formation of eddy current in the ulcer by blood flow, it is very easy to form thrombus. 8.How to prepare before surgery? Before the operation, the patient should be signed by his/her family members on the operation consent form, take medication according to the doctor's prescription and have sufficient rest on the night before the operation, fasting on the morning of the operation day, and emptying the urine before the operation. 9.How do I feel during the operation? Patients may feel discomfort such as heat in the head or neck when the contrast agent is injected during the imaging process, but the duration is only 1-2 seconds, and very few patients have nausea and vomiting. During the treatment (stenting), patients may feel neck or chest pain similar to angina attack, which is normal, but they should tell the doctor as soon as they have these feelings. 10. What should I pay attention to after the procedure? After the operation, the patient should drink more water to facilitate the discharge of contrast medium, try not to eat a high-protein diet within 24 hours, try not to move the operated leg and pay attention to observe whether there is any blood oozing out of the puncture compression place. After the operation, patients should take medication as prescribed by the doctor, and return to the hospital for follow up according to the doctor's request after being discharged from the hospital.