Carotid Artery Stenosis: Features, Causes, Symptoms, Treatment, Surgery, and Management

Definition of Carotid Artery Stenosis

Carotid artery stenosis is a condition in which the carotid artery narrows, reducing or blocking blood flow to the brain. The carotid artery is a major blood vessel that supplies blood to the brain through the neck, and is divided into the internal carotid artery (ICA) and the external carotid artery (ECA). The internal carotid artery plays a crucial role in supplying blood to the brain. Carotid artery stenosis is mainly caused by atherosclerosis, a disease in which fat, cholesterol, and calcium accumulate in the blood vessel walls, narrowing and stiffening the vessels. If the carotid artery narrows, insufficient blood supply to the brain can lead to serious cerebrovascular diseases such as stroke or transient ischemic attack (TIA).

Characteristics of Carotid Artery Stenosis

The main characteristic of carotid artery stenosis is the restriction of blood flow due to narrowing of the blood vessels, resulting in insufficient oxygen and nutrient supply to the brain. This significantly increases the risk of cerebrovascular disease. If the degree of stenosis is mild, there may be few or no symptoms. However, if the blood vessel is severely narrowed or blocked, symptoms will appear clearly and can lead to serious consequences. Carotid artery stenosis usually occurs in one carotid artery, but it can also occur in both. The risk of developing carotid artery stenosis increases with age.

• Degree of Stenosis: The degree of carotid artery stenosis is mainly evaluated by the stenosis rate. If the stenosis rate is 50% or higher, the risk of stroke increases sharply, and if it is 70% or higher, the risk of stroke is even higher. If the stenosis is 90% or more, blood flow is almost completely blocked, leading to serious consequences.
• Progressive Disease: Carotid artery stenosis can progressively worsen, with symptoms initially being minimal and then appearing suddenly. If the stenosis is completely blocked, cerebral blood flow decreases sharply, leading to a stroke.

Causes of Carotid Artery Stenosis

The main cause of carotid artery stenosis is atherosclerosis. Atherosclerosis is a disease in which cholesterol, fat, and calcium accumulate in the blood vessel walls, narrowing and stiffening the vessels. It is mainly related to aging. Other causes that can lead to carotid artery stenosis include:

1. Hypertension: Hypertension exerts constant pressure on blood vessels, damaging the artery walls and promoting atherosclerosis.
2. Hyperlipidemia: Hyperlipidemia, characterized by high levels of cholesterol and triglycerides in the blood, causes fat to accumulate in blood vessels, leading to carotid artery stenosis.
3. Smoking: Smoking causes inflammation in blood vessels and worsens atherosclerosis, which can lead to carotid artery stenosis.
4. Diabetes: Diabetes can damage blood vessels and promote atherosclerosis.
5. Genetic factors: Individuals with a family history and genetic predisposition to conditions such as hypertension and hyperlipidemia have a higher risk of developing carotid artery stenosis.
6. Irregular lifestyle habits: Lack of exercise, obesity, and poor diet can also contribute to the risk of carotid artery stenosis.

Symptoms of Carotid Artery Stenosis

Carotid artery stenosis often presents with no symptoms in the early stages. However, various symptoms can appear as the stenosis worsens or blood flow is blocked. The main symptoms of carotid artery stenosis are as follows:

1. Transient visual loss (TIA): Temporary loss of vision in one eye can occur with carotid artery stenosis. This is a symptom caused by temporary blockage of blood flow and vision recovers within a few minutes. However, TIA can be a warning sign of a stroke and should not be ignored.

2. Difficulty speaking: Slurred speech or difficulty in pronunciation may occur due to insufficient blood supply to the brain.

3. Arm or leg paralysis: Numbness or paralysis in one arm or leg can occur due to insufficient blood flow to the brain.

4. Dizziness: Insufficient blood supply to the brain can cause dizziness or loss of balance.

5. Headache: Sudden headaches can occur, potentially due to insufficient cerebral blood flow.

6. Acute stroke: If carotid artery stenosis becomes severe, a stroke can occur. Symptoms of stroke include paralysis on one side of the body, aphasia, and decreased consciousness.

Diagnosis of Carotid Artery Stenosis

Diagnosis of carotid artery stenosis uses several methods to evaluate the degree of vascular stenosis and the state of blood flow to the brain. The main diagnostic methods are as follows:

1. Ultrasound examination (carotid ultrasound): This is the most common examination method, and it can measure the degree of carotid artery stenosis and blood flow velocity. This examination is non-invasive and simple to perform.

2. CT angiography (CTA): This examination allows for a detailed view of the carotid arteries and cerebral blood vessels, accurately measuring the degree of stenosis.

3. Magnetic resonance angiography (MRA): Using MRI, this method allows for a precise evaluation of the carotid arteries and cerebral blood vessels, useful for viewing the fine details of the vessels.

4. Blood tests: Blood tests may be necessary to check for underlying conditions such as hyperlipidemia and diabetes.

Treatment and Surgical Methods for Carotid Artery Stenosis

Treatment for carotid artery stenosis is determined by considering the degree of stenosis, presence or absence of symptoms, and the risk of stroke. Treatment methods are broadly divided into non-surgical treatment and surgical treatment.

1. Non-surgical treatment

• Medication: Medication helps prevent thrombus formation and prevents the stenosis from worsening. Antiplatelet or anticoagulant agents are used to prevent thrombus formation, and antihypertensive drugs may be prescribed to control blood pressure. Statin drugs are also used to treat hyperlipidemia.
• Lifestyle modifications: Lifestyle changes are essential for the prevention and treatment of carotid artery stenosis. Regular exercise, a low-fat, low-salt diet, smoking cessation, and moderate alcohol consumption are necessary. Stress management and maintaining an appropriate weight are also important.

2. Surgical treatment

• Carotid endarterectomy: This surgery removes the fat and cholesterol that have accumulated in the intima of the carotid artery. This surgery is performed when the carotid artery is 70% or more stenosed or when blood flow is dangerously blocked. After surgery, blood flow is restored, significantly reducing the risk of stroke.
• Carotid stenting: This method involves inserting a stent into the carotid artery to widen the blood vessel. It can be chosen for patients who are unsuitable for surgery or who are high-risk. This method is less invasive than carotid endarterectomy, but there is also a risk of complications due to the stent.

Prognosis and Management of Carotid Artery Stenosis

The prognosis of carotid artery stenosis varies depending on the timing of treatment and the degree of stenosis. If treatment is prompt and appropriate, the prognosis can be good. However, if treatment is delayed or the stenosis is severe, a stroke or transient ischemic attack (TIA) can occur. In particular, if the stenosis is 70% or more, the risk of stroke is very high, so prompt treatment is essential.

Prognosis

• Timing of treatment: Early treatment leads to a very good prognosis. However, delayed treatment increases the risk of stroke and other complications.
• Post-surgical management: Regular checkups and treatment are needed after surgery to maintain vascular health. Lifestyle modifications are important for preventing recurrence.

Management methods

• Regular examinations: Patients with carotid artery stenosis should have regular ultrasound examinations or angiography to monitor their vascular condition.
• Medication: Management of hypertension, hyperlipidemia, and diabetes is important. This requires consistent medication and ongoing management of vascular health.
• Lifestyle modifications: A healthy diet, regular exercise, and smoking cessation can reduce the risk of carotid artery stenosis.

Conclusion

Carotid artery stenosis is a disease in which narrowed blood vessels restrict blood flow to the brain. While symptoms may be minimal in the early stages, it can cause serious cerebrovascular diseases. Early diagnosis and appropriate treatment are important, and restoration of blood flow through surgical or medical treatment is necessary. Maintaining a healthy lifestyle and regular checkups are essential for preventing carotid artery stenosis and managing vascular health.