Cerebrovascular disease is one of the three most common causes of death in the elderly, and the annual incidence of stroke in Western countries is 200/100,000, of which ischemic accounts for 83%, while about 50% of ischemic strokes have carotid stenosis. 1905 Chiari first reported that occlusive lesions of the carotid artery in the extracranial segment were associated with stroke, and pointed out that atherosclerosis at the bifurcation of the carotid artery and the dislodged emboli of the plaque were the direct cause of ischemic stroke. In 1953, Strully and DeBakey successively reported carotid artery endarterectomy (CEA), which was a milepost in surgical prevention and treatment of ischemic stroke. 1958, DeBakey reported carotid artery transverse exenteration endarterectomy, and in 1996, Darling reported internal carotid artery exenteration endarterectomy. In recent years, carotid endoluminal stenting has been widely performed at home and abroad, making carotid stenosis surgery more minimally invasive and safe. The main causes of extracranial carotid stenosis are: atherosclerosis, myofibrillar dysplasia, aortitis, trauma, and arterial compression. Carotid artery sclerosis-occlusive disease is the most common cause and occurs at the bifurcation of the common carotid artery, as well as at the branches of the aortic arch. The pathophysiological changes caused by carotid stenosis are twofold: (1) narrowing or occlusion of the carotid lumen, resulting in inadequate blood supply to the cerebral vessels; (2) ulceration of the atherosclerotic plaque with tiny cholesterol emboli or microthrombi, resulting in embolism of the distal cerebral vessels, causing transient cerebral ischemia (TIA) or cerebral infarction. Indications and contraindications for surgery A collaborative study (NASCET) of dozens of medical centers in more than Europe and the United States, with a follow-up of more than 10 years, found that in severe stenosis (70%-90%), the incidence of ipsilateral stroke within 2 years was 26% in the medical group and 9% in the surgical group; in moderate stenosis (3l%-69%), there was a significant difference between the two groups; in mild stenosis (<30%) There was no advantage in the surgical group. Main indications for carotid surgery: symptomatic carotid stenosis, >70%; those with high-risk factors for stroke, symptomatic >50%, asymptomatic >70%; double carotid stenosis, symptomatic side first; carotid stenosis secondary to vertebral artery lesion; carotid stenosis combined with coronary artery lesion, simultaneous surgery. American Heart Association AHA indications: Definite indications: 1 or more transient cerebral ischemia within 6 months, manifesting significant limited neurological deficits or unilateral blindness within 24 hours, and carotid stenosis >70%; 1 or more mild non-disabling strokes within 6 months, with signs or symptoms lasting more than 24 hours, and carotid stenosis >70%. Relative indications: asymptomatic carotid stenosis >70%; carotid stenosis <70< font="">% but in an unstable state, such as surface irregularity, ulceration or thrombosis; ③ severe restenosis after symptomatic CAE. Contraindications: patients with severe multi-organ insufficiency unable to tolerate the procedure; those within 3 months of acute myocardial infarction; those within 3 months of stroke onset. Surgical methods Currently, the main surgical methods for extracranial carotid stenosis occlusive lesions are: carotid endarterectomy (CEA), carotid stenting (CAS), and vascular bypass diversion (BYPASS). Carotid endarterectomy 1.Anesthesia: carotid plexus anesthesia or general anesthesia can be used; elevate the blood pressure during the blockade, 20%-30% higher than the original blood pressure: and keep it stable to increase the blood supply to the brain. 2.Position: lying position, head and upper body slightly elevated, about 15 degrees, lower limbs elevated l0 degrees. This can reduce the venous pressure in the head and intraoperative bleeding, and increase the venous return of the lower extremities; the head is tilted back and turned to the opposite side. Good cerebral protection measures and prevention of cerebral ischemic injury are one of the keys to successful surgery. Preoperative carotid compression test is not advocated, because the results of compression test are unreliable and may also squeeze causing carotid plaque dislodgement and cerebral infarction. The authors used the following methods: preoperative cerebral angiography to observe the bilateral cerebral artery supply and the compensation of the contralateral artery; cervical plexus anesthesia, which can be followed by observation of the patient’s consciousness, and if there is a disorder of consciousness, a diversion tube can be placed in time; intraoperative elevation of blood pressure to 120% of the original basal blood pressure; placement of carotid diversion tube in patients with general anesthesia. 3.Separation and exposure: take an oblique incision on the anterior edge of the affected sternocleidomastoid muscle, about 6-8era long, after separating the broad jugular muscle, external jugular vein and facial vein, separate and reveal the common, internal and external carotid arteries, pay attention to protect the vagus, subglottis and superior laryngeal nerves. The carotid sinus nerve and internal carotid artery brush nerve were closed with l% lidocaine at the bifurcation of the carotid artery to prevent intraoperative blood pressure fluctuations and cerebral vasospasm. Heparin was injected intravenously at lmg/kg body weight and systemic heparinization was performed. If the internal carotid artery is blocked experimentally, and if no impairment of consciousness and contralateral limb movement occurs for more than 3 minutes, it means that there is abundant blood supply to the brain and the affected carotid artery can be safely blocked for surgery; otherwise, a carotid diversion tube should be prepared for placement. Intraoperative placement of a diverter tube is required in about 10% of patients with CEA when the common carotid, internal carotid, external carotid and superior thyroid arteries are blocked separately. The indications are: blocking the carotid artery under cervical plexus anesthesia and the patient shows symptoms of cerebral tissue ischemia such as unconsciousness and sensory or motor dysfunction of the contralateral limb; preoperative cranial nerve instability or the need for general anesthesia; simultaneous lesions in the contralateral carotid artery, which makes the surgeon more cautious; blocking the common carotid and external carotid artery blood flow and measure the internal carotid artery pressure. 4.Intima-media stripping: sCAE is performed by cutting the common and internal carotid arteries longitudinally at the anterior wall of the carotid artery, and eCAE is performed by cutting the internal carotid artery obliquely at the bifurcation of the carotid artery, carefully separating the thickened intima from the outer membrane with a stripper, and completely stripping the thickened intima, making sure to remove the tiny fragments and floating tissues from the stripping surface, and if the distal intima is floating, it can be fixed with l to 3 stitches to prevent the intima from separating and causing internal carotid artery stenosis or occlusion. The carotid artery is closed with continuous sutures using 6-0 non-invasive sutures. The external carotid artery, common carotid artery and internal carotid artery are opened sequentially, taking care to prevent tissue debris or air from entering the internal carotid artery in the remaining vessels. The skin incision was built with a drainage tube, and the layers of the incision were sutured in turn. 5. Postoperative management: closely observe the changes in the patient’s mental status and blood pressure, and regularly check the blood flow of the internal carotid artery with ultrasound Doppler. Low-molecular heparin 5000 U was injected subcutaneously twice a day and changed to other oral anticoagulant drugs after the 5th postoperative day. To prevent cerebral edema due to postoperative reperfusion injury, 100 ml of mannitol can be given every 8 hours for 2 days. 6, the prevention and control of complications: incisional bleeding hematoma: postoperative close observation of incisional drainage, such as > 80ml / h, or tension hematoma, should be sent to the operating room in time to stop bleeding; carotid artery thrombosis: the main cause is the formation of the distal free edge of the internal carotid artery entrapment or improper suture, the patient can appear signs and symptoms of serious brain damage, should be immediately surgical exploration, if the blood supply to the brain can be restored within 2h, may not occur Cerebral perfusion injury: common in patients with severe carotid stenosis after surgery, in addition to symptomatic treatment, mannitol dehydration treatment should be given; stroke: despite the use of various preventive measures, neurological dysfunction still occurs from time to time, about 2%, if timely and effective treatment, most patients will not be left with serious neurological insufficiency symptoms; postoperative hypotension: relatively rare, mainly seen in carotid artery After stent placement, the pressure receptors of the carotid sinus are pressurized, and the blood pressure decreases and the heart rate slows down, so local lidocaine block or antihypertensive drugs can be given; postoperative hypertension: about 20% of patients can have transient hypertension after surgery, and if oral drugs cannot be controlled, intravenous drugs such as sodium nitroprusside are often needed to avoid serious complications: cranial nerve injury: the nerves easily injured during surgery are the sublingual nerve and its descending branches, the facial nerve and the mandibular branch, the laryngeal nerve and the laryngeal nerve. Pseudoaneurysm: It is common after arterial patching, and depending on the condition, emergency or elective surgical repair or trial closure of the pseudoaneurysm is possible. Carotid artery stenting Theron et al. were the first to use balloon cerebral protection technique in 1996, and then some new cerebral umbrellas were used in clinical practice. 1. Position and anesthesia: lying down position, femoral artery cannulation is selected according to the femoral artery, and the right femoral artery approach is generally chosen. Local anesthesia or general intoxication. 2.Surgical method: The femoral artery is punctured and cannulated, and the aortic arch and whole brain angiography are performed first to understand the site and degree of carotid stenosis and to measure the arterial caliber. After whole-body heparinization, an 8F introducer is placed in the common carotid artery. A guidewire with a carotid umbrella is passed through the guidewire to the normal internal carotid artery, the umbrella is opened, and balloon dilation is performed depending on the degree of stenosis. A stent of appropriate caliber is placed at the lesion, usually a self-expanding stent with a caliber 10%-20% larger than that of the normal common carotid artery, with the upper and lower ends exceeding the lesion by more than 1 cm each, and the umbrella and guidewire are retrieved. 3, postoperative treatment: 3 days to 5 days after surgery to give low-molecular heparin anticoagulation, after long-term oral enteric aspirin, ticlopidine or clopidogrel and other anti-platelet aggregation treatment. 4. Complication prevention and control: Although the operation is mildly traumatic, some more serious complications still occur, such as acute cerebral ischemia: when balloon dilation and stent placement are performed, the intracranial blood supply may stop suddenly and cerebral ischemic symptoms may appear, so the arterial blocking time should be minimized. Cerebrovascular spasm: intraoperative catheter and protective device operation can cause vasospasm, and those with obvious symptoms can be given intravenous poppy bases or nimodipine; cerebrovascular hemorrhage: because cerebrovascular is in a long-term low perfusion state, postoperative blood flow suddenly increases, rupture and hemorrhage can occur, and postoperative blood pressure should be controlled and lowered. It is simple and fast. It is easily accepted by patients, does not require an incision in the neck, reduces the risk of cranial nerve injury, infection and cervical hematoma, allows simultaneous management of carotid, vertebral and coronary artery lesions, reduces mortality in high-risk patients, etc. Some studies have shown that CAS has the same efficacy as CEA and has some advantages for patients at high risk for CEA surgery. Currently, CEA is the most commonly performed vascular surgery procedure to reduce the risk of stroke in the United States and most Western countries. CAS, on the other hand, has been performed more widely in recent years, but its long-term efficacy, however, needs to be further observed.