What is carotid artery stenosis?
The carotid artery is the main source of blood supply to the brain, and clinicians have found that the main cause of “stroke” is the narrowing and occlusion of the blood supplying arteries to the brain after long-term in-depth research. According to statistics, more than 60% of patients with cerebral ischemia are caused by carotid artery stenosis. So what is carotid stenosis? What are the causes of carotid artery stenosis?
As people age, the blood vessels are aging, resulting in the formation of “scale” like superfluous organisms attached to the walls of the blood vessels (commonly known as atherosclerosis), which obstructs the passage of blood flow and causes stenosis. Carotid artery stenosis occurs when “scale” appears on the carotid artery.
What are the causes of carotid artery stenosis?
How is the “scale” that causes carotid stenosis formed? The medical term for “scale” in the arteries 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.
What are the consequences and clinical manifestations of carotid artery stenosis?
As the carotid artery is one of the main blood supply arteries of the brain, when the carotid artery has different degrees of stenosis, the brain also has different degrees of ischemia. The main manifestations are: tinnitus, blurred vision, headache, dizziness, memory loss, weakness, drowsiness, insomnia, and excessive dreaming. In severe cases, repeated syncope, even hemiplegia, aphasia and coma may occur. A few people may have vision loss, partial blindness, diplopia, or even sudden blindness.
The most serious consequence is the shedding of atherosclerotic plaque, or what we call “scale”. The dislodged plaque can block the intracranial carotid artery and cause a cerebral infarction (stroke). As we all know, a “stroke” means hemiplegia, incontinence, inability to take care of oneself, and even loss of life.
How to detect carotid artery stenosis early?
Many people with carotid artery stenosis may not have any symptoms, but we should first understand the blood supply to the brain. The blood supply to the brain is mainly carried through four arteries: two internal carotid arteries and two vertebral arteries. After reaching the skull, these four arteries communicate with each other to form a network that supplies the brain with blood, a network called the basilar artery ring (Wiliis ring).
Wiliis
If the ring is congenitally incomplete or severely narrowed somewhere, then any one of the four supplying arteries will have ischemia in a part of the brain due to insufficient blood supply from the narrowing beyond a certain point, and thus some symptoms will occur. If the Wiliis
ring is intact, even if one artery is occluded, the other three vessels can still compensate for the cerebral blood supply through the Wiliis
If the Wiliis ring is intact, even if one artery is occluded, the other three vessels can compensate through the Wiliis ring to meet the blood supply needs of the brain and no ischemic symptoms will occur. However, we should not take the chance that it is too late to treat carotid artery stenosis if a stroke occurs. Therefore, middle-aged and elderly people over the age of 50 should have their carotid and vertebral arteries checked by ultrasound during their annual physical examinations to see if there are atherosclerotic plaques and stenoses in the arteries, and for early detection of carotid stenoses, early prevention and treatment should be actively carried out to avoid brain “strokes”.
Prevention of carotid artery stenosis?
The main cause of carotid artery stenosis is atherosclerosis, so the main prevention of carotid artery stenosis is to implement good living habits to prevent or delay the hardening and aging of arteries and blood vessels. Good lifestyle habits include: eating a light diet, eating more fruits and vegetables, and eating less greasy food; actively exercising and not smoking; patients with high blood pressure, high blood sugar or high blood lipids should actively control their blood pressure, blood sugar and blood lipid levels; middle-aged and elderly people over 50 years old can take small doses of aspirin under the guidance of a doctor to prevent cardiovascular events.
How is carotid artery stenosis treated? When do I need treatment?
There are three types of treatment for carotid artery stenosis: medication, open carotid surgery and carotid endovascular treatment (stenting).
1. Drug treatment. The basic method is the long-term use of antiplatelet drugs (such as aspirin, or the new strong antiplatelet drug clopidogrel), but only for asymptomatic patients with stenosis up to 50%, for patients with more than 75% stenosis further treatment is generally recommended.
2. Open carotid surgery. The basic method is endarterectomy to remove arterial stenosis and atherosclerotic plaque, restore blood supply to the brain, and eliminate the source of cerebral infarction emboli. The procedure is relatively mature and has been carried out for more than 50 years. Because the procedure requires blocking the carotid artery on the side of surgery, the perioperative stroke and mortality rate for this procedure used to be about 5.6%. The procedure now uses a diverter tube to remove the intimal plaque while maintaining the carotid blood supply during surgery, effectively reducing the perioperative stroke and mortality rate. The disadvantages of this procedure are the need for general anesthesia, large neck incision and trauma, and slow recovery. The advantages are complete removal of the hyperplastic intima and sclerotic plaque, less chance of reoccurrence of stenosis, and no need for lifelong antiplatelet and anticoagulant drugs.
3.Carotid artery endoluminal treatment. This is a method of applying balloon dilation and then placing stents in the narrowed carotid artery. This method has the advantages of small trauma, simple operation, fast onset of action, quick recovery, precise efficacy, and repeatable operation. Usually, a catheter with a diameter of about 2 mm is punctured at the root of the thigh under local anesthesia, placed into the femoral artery, delivered to the carotid artery stenosis, and then the balloon is dilated and then the stent is placed to complete the dilation of the carotid artery stenosis and improve the restoration of blood flow to the brain. The disadvantage is that the stent release process may induce the dislodgement of microscopic emboli of unstable plaque and cause “stroke” cerebral infarction, as well as vasospasm, intimal damage and the possibility of postoperative restenosis. In recent years, the use of stent systems with brain protection filters has been introduced, which can effectively prevent the occurrence of “stroke” brain infarction by catching the microscopic emboli that may be dislodged.
When is treatment needed?
Surgery or endoluminal treatment is required when
1. Carotid artery stenosis of more than 75%;
2.Carotid artery stenosis is less than 75%, but the symptoms of cerebral ischemia such as dizziness and blackness are typical, or the sclerotic plaque is unstable and easily dislodged;
3.The effect of drug treatment is not good, there is a history of stroke attack, or there is still a small stroke attack after cerebral infarction.
Precautions after surgery or endoluminal treatment?
The recent results of carotid stenting are encouraging and patient acceptance is high. The results of many international trials comparing endarterectomy and stentoplasty show that carotid stentoplasty is safer, less invasive and faster to recover than endarterectomy.
For patients who undergo endarterectomy, they need to take antiplatelet or anticoagulant drugs for about 36 months after the procedure, and lifelong anticoagulation and antiplatelet are not required. Metal stents are foreign bodies and have the potential for platelet aggregation and clot formation when in contact with blood in the body, so regular oral anticoagulation and antiplatelet medications are required after surgery. The usual medication is aspirin 100mg, 1 time/day, orally for life, and Bolivar (clopidogrel) 75mg, 1 time/day, orally for 3-6 months.
Both of the above procedures need to be reviewed at 3, 6, 9 and 12 months postoperatively with carotid ultrasound or CT, and annually thereafter. Maintain good lifestyle habits after surgery: strict smoking cessation, light, low-salt, low-fat diet; active exercise; active control of blood pressure, blood glucose and lipid levels.