On May 8, 2015, at the 2015 China Stroke Conference hosted by the Stroke Prevention and Control Engineering Committee of the National Health and Family Planning Commission and the Chinese Society of Preventive Medicine, the “Stroke Prevention and Control Guideline Series” compiled by the Stroke Prevention and Control Engineering Committee of the National Health and Family Planning Commission was unveiled. The following is the “Guidelines for Carotid Endarterectomy in China”. Carotid endarterectomy (CEA) has been regarded as an effective treatment for carotid artery stenosis and stroke prevention since the 1950s, but it has been carried out late in China. In order to treat carotid artery stenosis safely and effectively, it is necessary to grasp the basic and clinical knowledge related to carotid artery stenosis, which is briefly summarized. 1. Etiology: The main etiology is atherosclerosis, but there are some rare causes such as aortitis, fibromuscular dysplasia and post-radiotherapy fibrosis. 2. Pathology: Carotid atherosclerosis mainly involves the beginning of the internal carotid artery and the bifurcation of the internal and external carotid arteries, and can have various atherosclerosis causes such as intraplaque hemorrhage, fibrosis and calcification. The pathological characteristics of atherosclerosis. 3. Pathogenesis: Multiple mechanisms are possible, including 1) arterial embolism: embolism caused by local thrombus, cholesterol crystals or other debris fall; 2) acute occlusion: acute thrombosis caused by plaque rupture; 3) hypoperfusion ischemia: hemodynamic disorders caused by severe stenosis or occlusion. 4. Clinical manifestations: localization manifestations include contralateral limb muscle weakness, sensory abnormalities or loss, ipsilateral monocular blindness or visual-spatial ability abnormalities, and ipsilateral ipsilateral partial blindness. Patients with these localization symptoms can be called symptomatic carotid stenosis. Other clinical manifestations include dizziness, lightheadedness, or slowed reaction, memory loss, or even cognitive dysfunction. 5. Ancillary tests: Determining the diagnosis depends on effective adjunctive tests to assess CEA: CT angiography (CTA) has similar advantages; carotid ultrasound can yield good results in experienced hospitals, but requires strict quality control evaluation; magnetic resonance angiography (MRA), although it can also yield good image quality, is non-enhanced. MRA has relatively poor specificity. Regardless of the type of test, it is recommended that a standardized diagnosis be made using a combination of “side/ symptom/stenosis”, for example, severe left-sided symptomatic carotid stenosis; among them, stenosis is recommended to be measured according to the NASCET method. Treatment of carotid artery stenosis 1.Pharmacological treatment: including antiplatelet aggregation and control of risk factors, etc. For details, please refer to other relevant guidelines of the National Health and Family Planning Commission. 2.Carotid endarterectomy (CEA): still regarded as the primary choice for treatment of carotid artery stenosis, technical details are described in the following contents. Carotid artery stenting angioplasty (CAS): generally considered an effective alternative to CEA, although the comparison with CEA is still controversial, it is indeed widely performed in China. III. Rationale for CEA 1. Timing of surgery: Intervention within 2 weeks of transient ischemic attack (TIA) or stroke reduces the risk of stroke recurrence but also increases the possibility of reperfusion injury. Preoperative use of magnetic resonance diffusion techniques is recommended to exclude the possibility of de novo cerebral infarction, which can help to reduce the chance of reperfusion injury. Clinical evidence of CEA: Clinical trials have shown that CEA reduces the 2-year stroke rate by 17% in patients with severe stenosis and 6.3% in patients with moderate stenosis, both of which are preventive in nature, and reduces the stroke rate by 10% in asymptomatic patients with severe stenosis. 3. Indications for surgery: Since there is no evidence-based medical evidence in China, most of the relevant foreign guidelines are used. Symptomatic patients: non-disabling ischemic stroke or transient ischemic symptoms (including cerebral hemispheric events or transient blackness) within 6 months, with low to moderate risk of surgical intervention; non-invasive imaging confirms carotid stenosis over 70% or angiography reveals stenosis over 50%, and the expected perioperative stroke or mortality should be less than 6%. Asymptomatic patients: Asymptomatic patients with carotid artery stenosis greater than 70% and with an expected perioperative stroke or mortality rate of less than 3%. Patients with chronic complete occlusion: Given that the incidence of stroke in this group of patients may not be high, the guidelines do not recommend CE A treatment for this group of patients, but attempts at occlusion recanalization in some centers in recent years appear to be helpful, so it is recommended that occlusion recanalization be attempted only in symptomatic patients; when cerebral perfusion imaging confirms hemodynamic disturbances in the hemisphere on the side of the occlusion; only in experienced centers or by physicians; and when performed in a rigorous prospective setting. in experienced centers or physicians; and in rigorous prospective clinical trials are recommended. With the increasing effectiveness of pharmacological treatment, the indications for surgery should be stricter, and other factors are not recommended as indications for surgery. The intraoperative monitoring of activated partial thromboplastin time (APTT) or determining the dose according to the body weight can be recommended, and the neutralization of heparin is not recommended, diabetes mellitus must be strictly controlled, especially the use of statin, which is believed to gain long-term benefit; other treatments: some clinical reports suggest that the use of some hormones or peripheral neurotrophic drugs on the first postoperative day is beneficial to protect the function of cranial nerves, but there is no definite evidence to confirm this. 2. Anesthesia Most domestic centers use general anesthesia for surgery, which is more suitable for the patient’s own sensory experience and the stability of intraoperative vital signs. Compared with general anesthesia, local anesthesia can observe the changes in the neurological signs of the patient in real time after blood flow blockage, so it will reduce the use of diversion, but local anesthesia requires higher technical requirements for the operator and the anesthesiologist, which will bring additional risks and pain to the patient. The choice of anesthesia lies in the habits of different centers, and for hospitals without specialized training, general anesthesia is recommended for routine use. Intraoperative monitoring and diversion techniques Intraoperative monitoring is recommended for CEA to clarify the changes in cerebral blood flow during blocking and opening of the carotid artery, thus reducing the risk of surgery. Currently, the main monitoring methods include transcranial Doppler (TCD), cerebral saturation, stump torsion, electroencephalography (EEG), evoked potentials, jugular venous saturation and jugular lactate level. The best monitoring results can be obtained by using the combination of stump pressure and TCD or EEG. If the lesion is high, the upper edge of the incision should be turned posteriorly along the mandibular rim to avoid damaging the mandibular rim branch of the facial nerve, and the skin, subcutaneous and broad neck muscles are incised in turn. After revealing the carotid sheath, the common carotid artery, the internal carotid artery and the external carotid artery were exposed by freeing them and blocking the superior thyroid artery, the external carotid artery, the internal carotid artery and the common carotid artery, respectively. After longitudinal dissection of the common carotid artery and the wall of the internal carotid artery, the intima and plaque were removed, the superior thyroid artery, external carotid artery, internal carotid artery and common carotid artery were blocked, the internal carotid artery was dissected transversely along the beginning of the internal carotid artery, the plaque and the vessel wall were separated circumferentially along the circumference of the internal carotid artery, the wall of the internal carotid artery was lifted, and the intima and plaque were removed with a stripper, and the wall of the internal carotid artery was moved upward like a sleeve. The internal carotid artery wall was separated upward like a sleeve to the migrating part of the plaque and normal intima, and the plaque was sharply cut off and removed, and then the internal carotid artery was anastomosed end-to-end to the original incision. sCEA is the basis and standard of CEA and has a wider scope of application. sCEA is still one of the most important surgical procedures in China and abroad, although patching techniques and reversal CEA were introduced later. 2.Flipped carotid endarterectomy (eCEA): After blocking the superior thyroid artery, external carotid artery, internal carotid artery and common carotid artery respectively, the internal carotid artery is cut off transversely along the beginning of the internal carotid artery, the plaque and vessel wall are separated circumferentially along the circumference of the internal carotid artery, the wall of the internal carotid artery is lifted, and the intima and plaque are peeled off with a stripper, and the wall of the internal carotid artery is separated upward like a sleeve until The plaque and the normal intima were sharply cut off to remove the plaque, and then the end-lateral anastomosis of the internal carotid artery was made to the original incision. The procedure is completed by sequential suturing of the incision. eCEA has the advantage of avoiding incision and suturing of the distal internal carotid artery, which may reduce the rate of restenosis due to suturing. 3. Patch-forming repair technique: In sCEA, surgeons are concerned about postoperative loss of canal diameter or distal restenosis due to the technique of sequential suturing, and therefore, patch-forming repair techniques are used. The patches used include intravenous patches and synthetic materials, etc. After removal of the plaque by sCEA, one end of the patch is fixed to the upper edge of the incision, and then successive sutures are made separately. 4.Modified flipped carotid endarterectomy: Kumar et al. modified flipped CEA by first cutting the artery longitudinally from the proximal segment of the common carotid plaque to the fork of the internal carotid bulb, without cutting the internal carotid artery transversely, and directly flipping and peeling the plaque, which also achieved better efficacy, but in the actual operation, the operation is not easy. 5. The purpose of the diversion technique required in CEA surgery is to maintain certain cerebral blood flow after blocking the carotid artery so as to avoid cerebral infarction caused by the block. The choice of diversion or not: The need for diversion in CEA is somewhat controversial. It is recommended to determine the need for diversion by effective intraoperative monitoring, for example, if TCD monitoring shows that the ipsilateral middle cerebral artery flow is reduced to less than 50% after arterial block, the diversion technique is recommended. Some scholars use diversion in all cases, but there are risks such as damage to the intima of the artery by the diverter tube; others do not perform diversion in all cases and replace it with a substantial increase in blood pressure, but there is evidence that large intraoperative changes in blood pressure may cause damage to the patient’s cardiac function and are potentially risky. Diversion technique: Placement of a diversion is generally done after the artery has been blocked and dissected with the common carotid end placed first, followed by the internal carotid end after the diversion tube has been vented. And before the end of the artery is sutured, the diverter is removed, then the arterial lumen is deflated, and finally the remaining few stitches are sutured. (1) Regarding the choice of several surgical approaches: Although there are several surgical approaches, in general, each approach has its own strengths. The surgical technique itself is not advanced or not, but the key is to individualize the choice for the specific situation of the patient. sCEA versus eCEA: Data from Shah et al. between 1993 -1998 showed that eCEA did not result in the distal canal reduction seen after sCEA. eCEA had a lower complication rate than sCEA, including mortality and neurological deficit rates, and more importantly, follow-up revealed a restenosis rate of 0.3% for eCEA versus 1.1% for sCEA. This study, together with the prospective study by KoskasU and Entz et al, confirmed the advantages of eCEA. However, a review of the literature by Cao et al. showed that although eCEA may be useful in reducing restenosis rates, it does not significantly improve stroke or death in patients, and because of the small number of cases, it still cannot be proven superior to sCEA. eCEA, on the other hand, has some technical limitations, such as longer suture operation time and difficulty in externalizing the suture during end-lateral anastomosis. In addition, eCEA is difficult to remove all plaques in patients with extensive involvement of the common carotid artery. At the same time, because eCEA is performed by transecting the bifurcation of the internal carotid artery, and because the internal carotid artery needs to be separated along the entire circumference due to the need for external rotation, the carotid sinus nerve is likely to be severed, thus damaging the pressure receptors and losing the pressure perception reflex, resulting in postoperative {blood pressure or uncontrollable blood pressure fluctuations. Some studies have found that eCEA patients are prone to sympathetic arousal after surgery, resulting in increased hypertension, pulse pressure, and heart rate, and that some eCEA patients still require higher doses of antihypertensive medication even after an average of 9.5 months of interim follow-up. sCEA and patchplasty: There are many studies on patchplasty in sCEA, and most of the literature supports the use of patches intraoperatively. A meta-analysis has shown that patch repair reduces perioperative stroke, occlusion, and postoperative restenosis rates, and therefore patch revascularization has been consistently recommended in recent guidelines for eSVS and ASVS. First, the increased time and difficulty of the procedure may inadvertently increase the risk to the patient; second, the ideal patch material does not exist; venous patches that are too thin may rupture, and synthetic materials carry the risk of infection. Therefore, patch angioplasty should be viewed objectively, after all, the relevant studies are all older and the current guideline recommendations are based on these studies, but the surgical details and perioperative treatment at that time were not very satisfactory, while the development in the last 20 years, drugs can play a positive role in preventing acute occlusion and restenosis after CEA. (2) Micro carotid endarterectomy (Micro-GEA): Micro-CEA surgery is a product of modern microscopy combined with surgical techniques. Compared with CEA under the naked eye or under surgical magnification, Micro-CEA has many advantages. Second, the relationship between the layers of the arterial wall and the plaque can be clearly distinguished under the microscope, which makes the separation very clear and easy. Thirdly, the distal endothelium of the internal carotid artery can be handled more delicately. Under the microscope, the migrating part of the plaque and the normal endothelium can be clearly distinguished, and the distal endothelium can be sharply cut and trimmed without additional stapling, which reduces the possibility of postoperative thrombosis or entrapment; fourthly, during the suturing process, the stitch distance is smaller and the suturing is more meticulous, and it can avoid bringing the outer membrane tissue into the anastomotic margin, which reduces the possibility of postoperative thrombosis or distant restenosis. This reduces the possibility of postoperative thrombosis or distant restenosis. Although some clinical studies have shown the advantages of Micro-CEA, Micro-CEA is currently limited to neurosurgeons due to the additional training and equipment required, and there are still differences between microscopic and visual or surgical magnification procedures. (3) Discussion related to the surgical approach: For CEA, the anatomical landmarks are clear, the layers are simple, and the evaluation is not complicated from a purely technical point of view, but there are still some debatable issues regarding the surgical approach due to various variants or other factors. Longitudinal or transverse incision: CEA – generally chooses a longitudinal incision at the anterior border of the sternocleidomastoid muscle, with the advantage that it is easy to expose the mandibular and sternal angles, and can be applied for both {lower and lower surgery, but the postoperative scar is very unsightly; while the transverse incision is made along the texture of the skin of the neck, which can maintain the aesthetics but when the lesion is extensive or intraoperative diversion needs to be used, the exposure is limited. The choice between the two types of incisions is generally individualized based on the patient’s condition and the surgeon’s experience. Medial or lateral approach to the jugular vein: after the broad jugular dissection, – the usual choice is to go through the medial aspect of the internal jugular vein to expose the carotid bifurcation, ligating the transverse branches emanating from the internal and external jugular veins along the way, and to expose the hypoglossal nerve to prevent damaging it, exposing the jugular collaterals, which can also be cut if necessary, exposing the sternocleidomastoid artery, vagus nerve, etc. The lateral approach to the jugular vein can also be chosen, also from the anterior border of the sternocleidomastoid muscle, during which the internal jugular vein is pulled medially and 1-2 small branches from the sternocleidomastoid muscle may converge laterally from the internal jugular vein. In comparison, the lateral approach to the internal jugular vein provides better exposure of the anterior and distal parts of the internal carotid artery. At the same time, it is easy and fast to operate without dealing with the transverse branches of the jugular vein, and it is generally unnecessary to expose the hypoglossal nerve, thus reducing the chance of its injury, but it may increase the possibility of hoarseness due to the strain on the vagus nerve. Posterior cervical triangle approach: It is mainly aimed at the exposure of high CEA and can expose the internal carotid artery to the level of the first cervical vertebra. A straight incision is made at the posterior border of the sternocleidomastoid muscle, and care is taken not to damage the superficial auricular nerve and the lesser occipital nerve when performing subcutaneous separation; the paramedian nerve needs to be carefully separated during surgery, and the internal jugular vein and sternocleidomastoid muscle are pulled forward together to expose the carotid bifurcation; to prevent damage to the vagus nerve, it can be kept posterior to the carotid artery, and if necessary, it can be freed and moved anteromedially to prevent damage to the superior laryngeal nerve. Stroke, cardiovascular accidents and local complications, and complications elsewhere. Stroke and death: In the original North American Symptomatic Carotid Endarterectomy Study, stroke and mortality within 30 days after surgery were 5.8% in patients with symptomatic severe stenosis and 2.1% in patients with asymptomatic severe stenosis in ACAS. The American Stroke Association therefore requires perioperative death and stroke to be under 6% for symptomatic patients and under 3% for asymptomatic patients. Of these, the incidence of death after CEA is low, with most reports around 1%, of which myocardial infarction accounts for half. Therefore, careful preoperative and postoperative evaluation of cardiac and coronary artery function is important and should be followed by aggressive medical management. Other associated factors may include emergency CEA, ipsilateral stroke, contralateral carotid artery occlusion, and age >70 years. In the case of postoperative strokes, both hemorrhagic and ischemic, strict individualized intraoperative and postoperative blood pressure management, close intraoperative monitoring to reduce hemodynamically impaired infarction, gentle intraoperative manipulation to reduce the risk of embolism, and intensive antiplatelet therapy in the perioperative period are generally required. 2. Cardiovascular complications: Cardiovascular accidents in CEA include myocardial infarction, heart failure, arrhythmia, etc., which are relatively more common in Europe and the United States, but the incidence in several centers in China is less than 1%, which may be related to the lower incidence of myocardial infarction in the Chinese population compared with the Caucasians. However, serious complications are mostly accompanied by cardiovascular accidents, so it is still necessary to strictly evaluate the cardiovascular status of patients before surgery and give appropriate treatment. Local complications: including local hematoma, cranial nerve injury, and cutaneous nerve injury, etc. Among them, local hematoma is mostly related to incomplete local hemostasis and poor arterial suturing; therefore, the suturing technique should be strengthened, and intraoperative hemostasis should be carefully performed, especially for extensive venous and lymph node injuries during separation, and tight hemostasis should be performed; the incidence of cranial nerve injury after CEA is highly variable among centers, ranging from 1.7% to The incidence of post-CEA cranial nerve injury varies widely among centers, ranging from 1.7% to 17.6%, but in general, the incidence is around 5%, most commonly in the sublingual nerve, vagus nerve, and parasympathetic nerve, etc. Most of the symptoms are temporary and may be related to surgical traction edema, which usually improves 1-2 weeks after surgery, and may continue to improve until 6 months after surgery in individual patients. Injury to the cortical nerve is generally difficult to avoid in CEA, so patients may experience postoperative numbness around the jaw or behind the ear, but this does not cause other effects and generally improves to varying degrees about 6 months postoperatively. 4. Other complications: including pulmonary infection and non-healing wounds, which are usually associated with comorbidities and should be paid attention to during the preoperative evaluation. 5. Restenosis after CEA: The incidence of restenosis after CEA is generally low, between 1% and 3%, and the associated causes include improper intraoperative management, inadequate postoperative drug therapy, and excessive hyperplasia of smooth muscle and endothelium, etc. For patients with restenosis after CEA, CAS treatment is recommended as a priority to avoid the difficulty of secondary surgery.