Stroke, including ischemic stroke and hemorrhagic stroke, is the third leading cause of death in humans. About 80% of stroke patients have ischemic strokes, and about 1/3 of those who have an ischemic stroke are caused by atherosclerotic lesions of the carotid arteries. It is well known that ischemic stroke can cause different degrees and manifestations of neurological symptoms: hemiparesis, aphasia, and distortion of the mouth and eyes, and even coma or even death in severe cases, affecting the quality of life of middle-aged and elderly people and causing different degrees of burden for families. There are two main pathways for atherosclerotic carotid stenosis to cause stroke: 1) decreased blood flow and inadequate perfusion in the ipsilateral cerebral hemisphere caused by the stenosis itself; 2) cerebral embolism caused by the dislodgement of emboli after thrombosis is induced at the stenosis site. Currently there are two main treatment modalities for this disease, one is surgical carotid endarterectomy and the other is interventional treatment. Carotid endarterectomy has a long history of definitive results and was once the gold standard treatment for carotid atherosclerotic stenosis. In recent years, with the continuous progress of medical technology, especially the perfection and maturity of interventional technology, carotid stenting has gradually become a mainstream treatment from a non-mainstream treatment modality. Compared with carotid endarterectomy, interventional treatment has the following advantages: it is less invasive and non-invasive; it does not require general anesthesia and can be done while awake; the operation time is relatively short; and the operation is simple and the technique is relatively easy to master. The equipment used in the procedure: umbrella, dilating balloon and stent. Each of these materials is available in several sizes and brands, each with its own characteristics, and the operator chooses according to the characteristics and habits of the lesion. As the name implies, the umbrella is an umbrella-like structure with small 80-120um holes on its surface, which allows the passage of blood but intercepts the thrombus in order to be placed in the event of an embolism caused by the dislodgement of the thrombus from the lesion to the hemisphere during balloon expansion or stent placement. In addition, the guidewire attached to the umbrella is the operational access for the whole procedure, which is called “life on the line”. The balloon is the material used to dilate the lesion before or after stent placement, and its main purpose is to tear the plaque and fibrous components of the carotid stenosis to ensure that the stent is adequately molded into the lumen. Once the balloon reaches the carotid artery stenosis site, a mixture of contrast and water is pushed through a pressure pump or syringe outside the body, and the balloon expands. The balloon expansion will cause pressure on the plaque at the carotid artery stenosis site, thus loosening the plaque, and then the implanted stent will rebuild the carotid artery lumen. During this process, there is naturally a certain chance of plaque dislodgement. Most of the plaque will be intercepted by the umbrella, but there may be some “leakage”. This is why we cannot guarantee the absolute safety of the procedure. After the stent is inserted, the umbrella is removed and the intercepted clots are removed along with the umbrella, completing the procedure.