Does carotid stenosis have symptoms? Is there a treatment?

Author: Zou Yinghua, Chief Physician, Peking University First Hospital

Reviewer: Shen Chenyang, Chief Physician, Beijing Tiantan Hospital, Capital Medical University

The carotid artery is the main blood vessel responsible for supplying blood to the brain. It is divided into left and right sides. Like cerebral blood vessels and coronary arteries, the carotid artery can also become narrowed.

1. What causes carotid artery stenosis?

There are many causes of carotid artery stenosis, the most common of which is atherosclerosis. In adults, especially those over 40 years old, atherosclerosis can account for more than 95%.

The first reason for the occurrence of atherosclerosis is congenital factors. Genetic defects make it easy to develop atherosclerosis. The second is age factors. As age increases, the chance of atherosclerosis increases. The third is hypertension, hyperlipidemia, diabetes, chronic kidney disease, etc. The fourth is diet and environmental factors. Eating more vegetarian food and less high-protein and high-fat foods can delay the onset of atherosclerosis. If you like to eat high-fat and high-cholesterol foods, you may have a higher chance of atherosclerosis and it will occur earlier.

Why does atherosclerosis lead to vascular stenosis? Simply put, just like rust on a water pipe, due to congenital factors, bad genes, and acquired dietary structure or accompanying diseases, such as high blood pressure, high blood lipids, diabetes, etc., the elasticity of the blood vessel wall is reduced, and cholesterol and lipid plaques are deposited on the surface of the blood vessel wall or under the inner membrane of the blood vessel wall, forming atherosclerotic plaques that bulge on the inner wall of the blood vessel. The longer the plaque grows, the smaller the lumen of the blood vessel will be, leading to vascular stenosis.

Figure 1 Original copyright image, no permission to reprint

There are other less common causes of carotid stenosis, such as dizziness and cerebral ischemia in one's twenties or even teens. Examination reveals that the carotid artery is blocked or narrowed. This is often caused by vascular inflammation, such as large artery inflammation, which is more common in young people, such as women under 20 years old.

There are also congenital vascular development problems, such as fibromuscular dysplasia, a rare disease. In addition, due to treatment or trauma, such as surgery on the neck, scarring around the carotid artery can shrink and cause vascular stenosis; radiation therapy on the neck can also cause carotid stenosis.

2. What symptoms may occur due to carotid artery stenosis?

If carotid artery stenosis does not cause cerebral ischemia or plaque detachment, it is usually asymptomatic and is therefore often not taken seriously.

Once symptoms occur, the most typical manifestation is ischemia or cerebral infarction on one side of the brain. Cerebral infarction is often a small infarction, or TIA, which is a transient ischemic attack, manifests as temporary weakness or paralysis of one side of the limbs, but it will recover within a few minutes or hours. Generally, this symptom does not exceed 24 hours. This is very typical.

The second typical manifestation is the appearance of eye symptoms. Because the carotid artery branches off into the ophthalmic artery before entering the skull, carotid artery stenosis can cause ischemia in the eye, and vision suddenly becomes unclear or black, but it will soon get better. This is also transient and a typical symptom of carotid artery stenosis.

The third symptom is non-specific. You may feel dizzy frequently, and examination may reveal carotid artery stenosis.

The most serious consequence of carotid artery stenosis is cerebral infarction caused by plaque detachment. After arteriosclerosis, atherosclerotic plaques are produced on the blood vessel walls, making the arterial lumen narrower and narrower. When the diameter stenosis exceeds 50%, plaque thrombosis will occur. The surface thrombus will detach or the plaque itself will detach and be washed into the cerebral blood vessels, causing cerebral infarction. Blockage of important cerebral blood vessels or a large area of ​​cerebral infarction will lead to disability or life-threatening.

Therefore, it is very important to detect whether there is plaque or stenosis in the carotid artery as early as possible. Ultrasound is the first choice for screening whether there is stenosis in the carotid artery.

Carotid artery stenosis is divided into mild, moderate and severe. Ultrasound examination can determine the degree of stenosis based on blood flow velocity. A stenosis of less than 50% is mild stenosis; a stenosis of 50%-70% is moderate stenosis; and a stenosis of more than 70% is severe stenosis.

3. How to treat carotid artery stenosis?

There are currently 3 main treatments for carotid stenosis.

Patients with carotid artery stenosis less than 70%, that is, mild or moderate stenosis, and no clear plaque detachment can be treated with drugs. The most commonly used drug for antithrombotic treatment is aspirin, which is the world's first choice. If one drug does not work, it can also be combined with clopidogrel; the most commonly used anti-lipid treatment is statins that reduce cholesterol deposition; patients with underlying diseases should actively treat the primary disease, such as diabetes and hypertension.

Severe carotid artery stenosis, with a stenosis of more than 70%, should be treated surgically to prevent plaque rupture and detachment, leading to cerebral infarction. Currently, there are two types of surgical treatment: carotid endarterectomy and intravascular interventional therapy.

Carotid endarterectomy is a surgery that involves making an incision in the neck to expose the blood vessels and making a longitudinal incision, or even cutting the blood vessels, removing all the hyperplastic endothelium and plaques inside the blood vessels, and then suturing the blood vessels. Carotid endarterectomy is the most classic and one of the most widely used surgical methods in the world.

Figure 2 Original copyright image, no permission to reprint

Intravascular interventional treatment involves puncturing the thigh or upper limb. More than 95% of punctures are done in the femoral artery. After the puncture, a very small sheath is placed in the blood vessel, and a thin catheter is inserted through the sheath to reach the carotid artery stenosis lesion. A brain protection device is then placed through a very thin guide wire. Under the guidance of the brain protection guide wire, a very thin balloon is placed on it to prop up the narrow area first. After the stenosis is opened, the balloon is removed and the stent is placed. The stent is used to fix the plaque on the blood vessel wall so that the lumen is no longer narrowed. This is also called carotid artery stenting.

Figure 3 Original copyright image, no permission to reprint

Generally speaking, there are three treatment methods: drug therapy, carotid endarterectomy, and carotid artery stenting. The specific treatment method to be chosen should be based on the specific situation and recommended by a professional doctor.