According to the Ministry of Health, the annual incidence of stroke in China reached 200/100,000 in 1997, more than 3 million people, the number of deaths due to stroke has jumped to the first place, and about 3/4 of the survivors have lost their labor force to varying degrees. Ischemic stroke and carotid artery stenosis One of the causes of ischemic stroke is atherosclerotic stenosis of the carotid artery. Atherosclerosis of the carotid artery is reported to account for about 70% of stroke patients over 60 years of age in the U.S. Tegler examined 168 stroke patients by ultrasound and found that 109 cases were due to carotid stenosis. Cerebral angiography performed within 12 hours of the stroke revealed arterial stenosis in more than 90% of cases, 50% of which were in the extracranial carotid artery. It is evident that ischemic stroke is closely related to atherosclerotic stenosis of the carotid artery. The diagnosis of carotid stenosis has for many years relied on digital subtraction arteriography (DSA), which is still the “gold standard”. However, DSA is somewhat invasive and may occasionally result in complications such as atherosclerotic plaque or thrombus dislodgement and arterial spasm, so in recent years, non-invasive tests have become increasingly popular, mainly ultrasound, magnetic resonance angiography (MRA) and CT angiography (CTA). Surgical treatment of carotid artery stenosis As early as the early 1950s, Spence (1951) first performed carotid endarterectomy in the U.S. In 1953, DeBakey successfully reconstructed blood flow by performing endarterectomy for complete occlusion of the internal carotid artery. Over the past half century, especially after the publication of the results of the North American Symptomatic Carotid Endarterectomy Trial Collaborative Group (NASCET) and the European Carotid Surgery Trial Collaborative Group (ECST) in 1991, the status of the endarterectomy approach has become unquestionable, with an annual volume of 100,000 procedures in the United States. Carotid endarterectomy in China was carried out late, largely because of the traditional belief that carotid lesions in the extracranial segment are rare in the East. This concept obviously lacks foundation and is inevitably biased. Fortunately, the neurosurgical community in China has paid attention to this problem, and the country has included it in the “Ninth Five-Year Plan” and “Tenth Five-Year Plan” key research projects. The surgical indication of carotid endarterectomy depends on the clinical manifestations and lesion characteristics of the patient. In the past, most attention was paid to the degree of arterial stenosis due to atherosclerosis, but in recent years, more and more emphasis has been placed on the pathology of atherosclerotic plaques. Many data suggest that unstable plaques (thin or ruptured fibrous cap, ulcer formation, high lipid content within the plaque, or bleeding) are more likely to produce symptoms than stable plaques. Therefore, most scholars nowadays believe that for patients with TIA (transient ischemic attack): 1. surgery should be considered for all patients with multiple episodes and confirmed corresponding carotid stenosis; 2. carotid stenosis ≥70% despite a single episode; 3. plaque instability confirmed by imaging; 4. medical treatment is not effective. Those with frequent TIA episodes, high carotid stenosis (>90%) or thrombosis, and sudden disappearance of pre-existing neck murmur should be operated as early as possible or even in an emergency. In addition to TIA, surgery should also be considered in patients who have already had a stroke and whose examination confirms the presence of carotid stenosis. Because studies have shown that the annual recurrence rate of ischemic stroke due to extracranial carotid lesions is 5% to 20% and reaches 50% at 5 years, if treated with endarterectomy after the first stroke, the annual recurrence rate can be reduced to 2%. Of course, the purpose of endarterectomy is not only to improve the existing dysfunction but also to prevent another stroke, and the timing of the operation should be different from person to person. Whether to operate for asymptomatic carotid artery stenosis is controversial. Most scholars advocate that surgery should be considered if the stenosis is >70% or if the plaque is unstable, even if there are no symptoms for the time being. There have been many advances in intraoperative monitoring techniques for carotid endarterectomy, including vascular integrity monitoring (residual pressure measurement, local cerebral blood flow measurement, transcranial Doppler ultrasound and intraoperative OPG, etc.) and brain function monitoring (EEG, somatosensory evoked potentials and near-infrared spectroscopy, etc.), and the most clinically used are EEG, evoked potentials and transcranial Doppler ultrasound. Regarding intraoperative shunts, although there are both routine shunts and never shunts, most scholars believe that they should be determined according to the patient’s specific situation and intraoperative monitoring results. In recent years, some scholars have started to promote cervical plexus block anesthesia (“third generation phenomenon”) again in carotid endarterectomy. They believe that the proportion of patients requiring endarterectomy is significantly higher in patients with hypertension, coronary artery disease, diabetes mellitus, and pulmonary disease, and that the less invasive the procedure is for these “vulnerable” patients, the better. However, in general anesthesia, tracheal intubation, general anesthesia and excessive monitoring may affect the internal environment more than the endonectomy itself, while local anesthesia is less invasive. Moreover, for cerebral ischemia, the awake patient is a more sensitive monitoring system than EEG, transcranial Doppler ultrasound, etc. Some scholars who advocate the use of local anesthesia believe that it is safer for cardiac patients to undergo carotid endarterectomy under local anesthesia, but causing tachycardia and hypertension in patients will increase myocardial oxygen demand, therefore, most scholars currently still use general anesthesia.