Science in Action | Carotid stenosis - the "number one killer" of human health

The main channels of blood supply to the brain are the carotid system and the vertebral artery system, with the carotid arteries on both sides supplying blood to the brain tissue and accounting for more than 80% of the blood required by the human brain. Once the carotid arteries are narrowed, it goes without saying that the blood supply to the brain will be compromised. Before we begin today's topic, let's look at some of these statistics.

In the 2015 China Cardiovascular Disease Report, stroke is now the leading cause of death in the composition ratio of major diseases among urban and rural residents in China, and is also the leading cause of death for both men and women in China. According to the Chinese Guidelines for the Diagnosis and Treatment of Carotid Stenosis (2017 Edition) study, the mortality rate of stroke in rural areas was 150.17 per 100,000 people and 125.56 per 100,000 people in urban areas, and the labor force population aged 40 to 64 years accounted for nearly 50%. Ischemic strokes account for approximately 80% of stroke patients, and in 25% to 30% of these ischemic strokes, there is an extremely strong association with carotid stenosis. Our topic today is to explore with you, what does carotid stenosis, really look like?

Science in Action | Carotid stenosis - the "number one killer" of human health

The true face of carotid stenosis.

Can cause a variety of diseases

Carotid stenosis, a condition that can cause strokes or transient ischemic attacks, is a narrowing and occlusion of the common and internal carotid arteries. It is like a traffic jam that begins to occur on a major traffic lane. One of the causes of stenosis is the accumulation of plaque, a deposit in the blood, which is known medically as atherosclerosis.

Medically, atherosclerosis is the main cause of carotid stenosis, accounting for about 90% of cases. Other diseases, such as entrapment aneurysm, fibromuscular dysplasia and arteritis, can also cause carotid stenosis. Currently, atherosclerotic plaques in the carotid arteries are present in 1/3 of adults in China. Among people aged 70 to 89 years, the number of people with carotid plaque is even higher at 63%.

If this situation continues, the narrowed blood vessel walls will become narrower and narrower, and the blood vessels, the "highways" of the body, will face more and more serious traffic congestion, or even complete obstruction of blood flow through, which is called "occlusion". This is called "occlusion." At this point, it is easy to induce a stroke. Strokes occur when the brain loses its normal blood supply. Although it only lasts for a few minutes, the brain cells will soon start to die. Therefore, stroke is one of the diseases that have a very high mortality and disability rate.

The carotid artery, the large vessel that carries oxygen-carrying blood, from the heart to the head, face and neck, is one of the main blood supply vessels to the brain. Therefore, the narrowing of the carotid artery will lead to insufficient blood and oxygen supply to the brain. If the brain, the "CEO" of the body, is already malnourished, the rest of the body will be even more neglected.

In patients with severe carotid artery stenosis, even if controlled by effective medication, the incidence of cerebral ischemic events within 2 years can be as high as 26%; and more than 60% of cerebral infarctions are caused by carotid artery stenosis, and severe cerebral infarction can even lead to disability or even death. Therefore, carotid artery stenosis has become the "number one killer" that endangers people's health in today's society, so people have to pay attention to and prevent it.

Asymptomatic carotid artery stenosis

together with

Symptomatic carotid artery stenosis

Hypertension, hyperlipidemia, diabetes and smoking are all culprits in carotid artery stenosis, especially the "terrorist" of hypertension. Therefore, one of the priorities of prevention is to control blood pressure. By keeping blood pressure within normal limits, cerebrovascular disease caused by carotid stenosis can be effectively alleviated. Encouraging smoking cessation can also help to prevent carotid artery stenosis from causing the corresponding disease.

So with that said, what symptoms are present that would suggest carotid stenosis? The first thing we need to understand is that carotid stenosis is divided into asymptomatic carotid stenosis and symptomatic carotid stenosis. This requires us to understand it in two ways.

Patients with asymptomatic carotid stenosis have only a mild headache or dizziness. In the early stages there are mostly no symptoms, and occasionally there may be symptoms such as sudden onset of dizziness and headache, numbness in the extremities, transient blindness, or an inability to speak with the tongue. Most of these symptoms disappear quickly, and most patients recover within minutes, making them relatively unnoticeable.

Science in Action | Carotid stenosis - the "number one killer" of human health

The main reason for such symptoms is cerebral ischemia, which may manifest as transient blackness or visual field loss on the side of carotid stenosis (that is, a sudden blackness in front of the eyes, blurred vision or other feelings), and also manifestations such as inflexibility of limb movement. In severe cases, it can manifest as cerebral infarction, resulting in hemiplegia, aphasia, cerebral nerve damage, coma and other corresponding signs, symptoms and imaging features on the opposite side of the lesion.

Because such symptoms are not obvious and are difficult to detect, they can be extremely dangerous when they occur in certain specific situations, for example, in driving, in dangerous underground work, or in working at height, and if blurred thinking or transient blindness occurs, it is likely to cause serious life-threatening problems. Therefore, it is important to be vigilant and pay extra attention to these symptoms.

So, what does symptomatic carotid stenosis look like again?

Symptomatic carotid stenosis is defined as the occurrence of one or more of the following symptoms within the previous 6 months.

(i) Transient ischemic attack.

(ii) Transient blackout: a sudden loss of vision lasting from a few seconds to several hours, which is a characteristic symptom of carotid stenosis.

(iii) Mild, non-disabling strokes caused by the affected intracranial vessels.

Once symptoms such as the above appear, whether mild or severe, they must be taken seriously. Then, we should cooperate with the doctor for the appropriate examination.

5 Tests for Carotid Artery Stenosis

physical examination

All patients with carotid stenosis are subjected to a neurological physical examination, which is to make further diagnosis based on the state of expression, facial symmetry, speech, consciousness, motor function, limb tone, ataxia test, sensory function, etc. Some patients may be detected with signs of stroke.

The doctor will also perform carotid ultrasound, CT angiography (CTA), MRI, and cerebral angiography to determine the exact location and extent of carotid artery stenosis. These sound like very complex operations, and we have a general idea of how these specialized diagnostic methods are performed.

sonication

Ultrasonography, the clinical test of choice to screen for carotid stenosis, can diagnose the site and extent of arterial stenosis or occlusion. Moreover, ultrasonography is non-invasive, low cost and reproducible. The disadvantage is that it cannot be accurately quantified for multiple stenoses and may overestimate the degree of stenosis.

magnetic resonance examination

Magnetic resonance imaging angiography (MRA) can show the anatomical site and degree of carotid stenosis, but this test is not indicated if the patient has a ferromagnetic metal implant in the body, such as a pacemaker or the like.

CT scan

CT examinations include coronary CT examinations (CTA) and CT perfusion scans (CTP).CTA provides anatomic and morphologic information on the aortic arch, supra-arch vascular openings, and carotid arteries to assess the degree and location of stenosis in the carotid arteries.CTP obtains perfusion information on blood flow in the brain.

Whole brain angiography (DSA)

DSA is the "gold standard" for the diagnosis of carotid stenosis. Unlike CT and MR, DSA is invasive and requires hospitalization in the operating room under local anesthesia. DSA is useful for observing the type of aortic arch, the nature of the carotid stenosis, such as the site of stenosis, the degree of stenosis, the overall pattern of the plaque, or the presence of ulceration of the plaque, as well as the integrity of the contralateral carotid artery, vertebral artery, and the intracranial ring of Willis. If the patient is likely to undergo interventional treatment, non-invasive examinations such as CT are preferred, and angiography is performed after admission to clarify the site and nature of the lesion, followed by interventional treatment at the same time.

Science in Action | Carotid stenosis - the "number one killer" of human health

Here we present to you the degree of carotid artery stenosis, based on DSA findings, classified into 4 grades according to the NASCET method (North American Symptomatic Carotid Artery Endothelial Stripping Test), which are.

① Mild stenosis is a <30% reduction in the internal diameter of the artery.

(ii) Moderate stenosis is a 30%-69% reduction in the internal diameter of the artery.

(iii) Severe stenosis is a 70%-99% reduction in the internal diameter of the artery.

④ Complete occlusion is a pre-occlusive state with >99% stenosis.

Based on these specialized diagnoses, health care providers can then more accurately grasp the condition and thus conduct further consultations.

Therapeutic measures for unblocking stenosis

The principle of treating carotid stenosis is to reconstruct normal blood flow channels and restore normal blood flow through them. This includes removing the plaque that has collected in the stenosis and placing a stent in the stenosis to restore the normal caliber of the vessel. In short, everything is done to improve the congestion of the "highways" in the body. Patients with severe cases will be treated with revascularization or endovascular stenting. We have the following treatment options.

Control blood pressure, blood sugar, blood lipids, and get regular medical checkups.

1. repeat antihypertensive drugs as prescribed, blood pressure control target: <140/90 mmHg. antiplatelet and anticoagulant therapy, antiplatelet drugs available include aspirin, clopidogrel, etc. Low-dose aspirin (75-150 mg/d) can be as effective as higher doses; aspirin combined with clopidogrel reduces the incidence of cardiovascular events, and the risk of bleeding should be guarded against. The use of conventional anticoagulants, such as warfarin, in combination with aspirin does not reduce the incidence of cardiovascular events and may increase the risk of major bleeding. The readers here need to be reminded that medication must be strictly followed and taken under the guidance of a doctor so that the disease is cured rather than causing more serious consequences.

2. For patients with carotid stenosis in combination with diabetes mellitus, dietary management must be enhanced. Control the target value of blood glucose: non-fasting blood glucose of 11.1 mmol/L or less, and glycated hemoglobin should be <7% during treatment.

3. Patients are usually advised to take a statin for lipid-lowering therapy. For patients with carotid stenosis who are at high risk of stroke, it is recommended that LDL levels be controlled to less than 100 mg/mL.

Nutritional support

1. Eat more vegetables and fruits and foods containing high quality protein.

2. Limit salt: Excess salt may lead to increased blood pressure. Healthy adults should have a daily sodium intake of less than 1500 mg.

3. Limit the intake of cholesterol: try to avoid foods containing saturated fatty acids or trans fatty acids, such as fried foods, animal fats (e.g. lard, butter), etc.; choose foods containing monounsaturated fatty acids or polyunsaturated fatty acids, such as olive oil, fish, beef, etc.

interventional therapy

The use of carotid endarterectomy (CEA) or carotid stenting (CAS), in addition to antiplatelet and statin medications, strict blood pressure and glucose control, and smoking cessation, can further reduce the incidence of ischaemic stroke events. CAS is a relatively less invasive treatment that can be performed under local anesthesia.

The current clinical evidence comparing the advantages and disadvantages of CAS and carotid endarterectomy (CEA) has not yielded significant differences. CAS may be considered for symptomatic carotid stenosis ≥50% or asymptomatic carotid stenosis ≥70%. Interventional treatment is less invasive, can be performed under local anesthesia, and has significant advantages over CEA in terms of myocardial infarction, damage to cerebral nerves, wound infection, and bleeding. CAS is also more advantageous for patients with higher or lower lesions that are inaccessible for surgery, patients with combined intracranial artery stenosis, and patients with combined severe cardiopulmonary disease that cannot tolerate general anesthesia. Also to prevent in-stent thrombosis, CAS requires oral dual antibodies for 1-3 months after the procedure.

Prognostic care for carotid artery stenosis

and daily prevention

Careful daily care and proven health education can maximize the ability of patients with carotid stenosis to recover and return to their daily lives sooner. So if we are in the position of caring for a patient with carotid stenosis, what are the key points of prognostic care that we should know? Broadly speaking, there are three areas that should be addressed.

Daily medication and diet

It should be done by following medical advice, not stopping the medication and reviewing it regularly to prevent the possibility of complications and secondary diseases. It is also important to eat a light diet with natural cereals, vegetables, and fiber-rich foods, fruits, etc. Note that greasy and high-calorie foods are prohibited.

Disease monitoring in daily life

Regular and reasonable ultrasound, CTA or cerebral angiography reviews, regular blood glucose, lipid and blood pressure tests are recommended by your doctor, taking into account your condition. Be keenly aware of these "risk factors".

Science in Action | Carotid stenosis - the "number one killer" of human health

Life Health Management

People who smoke need to quit smoking early and increase physical activity. Depending on your situation, you can exercise at least 30 minutes a day, at least 3 to 4 days a week. As the saying goes, "go to bed early, get up early, exercise", keep your weight within normal limits, and have your blood lipids tested regularly. In addition, fat intake can affect cholesterol levels in the body, so extra care is needed.

Editor: Guo Lei

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