Carotid artery stenosis is a condition in which blood vessels age as people age, resulting in the formation of a “scale” of superfluous material in the lumen of the vessel that adheres to the vessel wall (commonly known as atherosclerosis), blocking blood flow and causing narrowing of the vessel. Carotid artery stenosis occurs when “scale” appears on the carotid artery. Stenosis is commonly found at the bifurcation of the carotid artery. Carotid artery stenosis can cause intracranial ischemia (lack of blood supply to the brain) and a series of clinical symptoms. What are the causes of carotid artery stenosis? How does the “scale” that causes carotid artery stenosis form? The medical name for the “scale” in the arterial vessels is atherosclerotic plaque. As we age, and under the influence of a series of factors such as smoking, hypertension, hyperlipidemia, reduced exercise and emotional stress, the blood vessels age and calcium and lipid are deposited on the inner walls of the vessels, forming “scale”-like hardened plaques that make the artery walls hard and lose elasticity. At the same time, due to the development of lesions, some of the plaques gradually protrude into the lumen of the vessel, resulting in luminal stenosis. Risk factors for carotid artery stenosis The main risk factors for carotid artery stenosis caused by atheroma include smoking, hypertension, hyperlipidemia, diabetes and obesity. Others are heart disease, unhealthy eating habits, and lack of exercise. Clinical manifestations and consequences of carotid stenosis Since the carotid artery is one of the main blood supply arteries to the brain, when there are different degrees of stenosis in the carotid artery, the brain also suffers from different degrees of ischemia. The most common is transient ischemic attack (TIA), which is often sudden, manifested as dizziness, dizziness, fainting; blackness in front of the eyes, especially temporary blackness in one eye; numbness and weakness in arms and legs; and slurred speech. This symptom may appear only for a few minutes or for several hours, but disappears completely within 24 hours, which is often called “mini-stroke” or “cerebral vascular spasm”. In addition, patients may also present with prolonged or permanent neurological damage, strokes (cerebral infarction, lacunar infarction), which are most likely caused by carotid artery stenosis. Many other patients have no obvious symptoms, but are mostly over 50 years old and often have clinical manifestations of hypertension, diabetes mellitus, and atherosclerosis. Many are found during routine physical examinations or when examined for other diseases. The most serious consequence is the shedding of atherosclerotic plaque, or what we call “scale”. The dislodged plaque can block the carotid artery and cause a cerebral infarction (stroke). As we all know, “stroke” means hemiplegia, incontinence, inability to take care of oneself, and even loss of life. Stroke is the third most common cause of death after coronary heart disease and cancer. Half of these strokes are caused by carotid artery stenosis and blood clots. Screening methods Although we find that many stroke patients have carotid stenosis, many of these patients had carotid stenosis before the stroke occurred. Usually, the following methods are used to determine the diagnosis of carotid stenosis: (1) Transcranial ultrasound Doppler (TCD): It can be used to examine the presence or absence of stenosis in the intracranial and extracranial vessels by measuring the velocity and direction of blood flow, if there is stenosis compensation, and the condition of collateral circulation. (2) Cervical vascular ultrasound: It can determine the blood flow velocity, the presence or absence of stenosis and the degree of stenosis, plaque softness and other information. (3) Combined head and neck CTA scan or whole brain DSA angiography: it can observe the neck and intracranial vessels from a morphological point of view, determine the extent of stenosis and provide the most visual information for the next step of treatment. Treatment The treatment for carotid stenosis is either microscopic carotid endarterectomy or endovascular stenting. Microscopic carotid endarterectomy is currently the leading international option for the treatment of most carotid stenoses. In microcarotid endarterectomy we remove the atheromatous plaque from the carotid artery and re-establish uninterrupted blood flow to the brain. Patients with severe medical systemic disease that cannot tolerate the procedure may undergo endovascular stenting, in which a balloon is introduced into the vessel to the plaque and a stent is placed to expand the vessel wall. Microscopic carotid endarterectomy at Johns Hopkins Hospital has the highest outcome in the United States, with a published mortality rate of 0.8%. Prevention of carotid artery stenosis The main cause of carotid artery stenosis is atherosclerosis, so the main prevention of carotid artery stenosis is the implementation of good lifestyle habits to prevent or delay atherosclerosis and aging. Good lifestyle habits mainly include: a light diet, more fruits and vegetables, and as little greasy food as possible; active exercise, no smoking; patients with hypertension, hyperglycemia or hyperlipidemia should actively control blood pressure, blood sugar and lipid levels; middle-aged and elderly people over 50 years old can take a small amount of aspirin under the guidance of a doctor to prevent cardiovascular and cerebrovascular events.