Introduction
A stenosis is a narrowing in an artery or vein. Carotid artery stenosis is caused by a build up of atherosclerotic plaque within the artery. This build up of plaque reduces the lumen or channel where blood is flowing and is a common cause of stroke.
The carotid artery is the main blood supply to the brain. A stroke may occur due to not enough blood flowing through the carotid artery or due to particles of plaque, or clotted blood, breaking away from the artery and passing upwards to the brain, blocking small blood vessels and damaging the brain tissue. This is a stroke and may cause a range of symptoms from paralysis, weakness, loss of speech, loss of vision and death in severe circumstances.
Surgery to remove the plaque may be performed to prevent stroke. The need for surgery depends on the severity of the stenosis, the age of the patient, other medical issues and whether there have been any symptoms from the carotid stenosis.
Causes
Atherosclerosis is the build up of plaque in the arterial wall. It is very common in our society and may occur throughout the body. It is the same disease process that causes cardiac disease and peripheral arterial disease.
Atherosclerosis is due to plaque formation. Plaque is made up of cholesterol, fibrous tissue and inflammatory cells. The formation of plaque is complex but is associated with genetics (family history), smoking, diabetes, high cholesterol, high blood pressure, poor diet and sedentary lifestyle. Controlling these risk factors is crucial to reduce plaque formation and to prevent the development of stoke or other arterial disease.
Symptoms
The symptom of carotid artery disease is stroke. The typical symptoms of stroke include arm or leg weakness or paralysis, facial drooping, speech difficulties or visual loss.
These symptoms may last a short period of time (a transient ischaemia attack or TIA) or can be longer lasting or permanent (stroke). Temporary blindness (amaurosis fugax) may also occur. If these symptoms ever occur, then urgent medical review is extremely important.
Tests
Carotid artery stenosis may be detected on physical examination with a loud whooshing sound heard over the carotid artery using a stethoscope.
Ultrasound or duplex scanning is a very sensitive test to assess and diagnose carotid artery stenosis. Both CT scan and MRI scan are used to confirm ultrasound findings, plan treatment and also assess the brain for signs of stroke.
Diagnosis
Assessment for carotid artery stenosis should be performed on any patient who develop symptoms of a stroke. Carotid ultrasound should be performed along with general medical assessment for cardiac disease and the other risk factors for atherosclerosis.
In patients with a strong family history of stroke, or with a history of extensive arterial disease, surveillance of the carotid arteries looking for stenosis should be considered.
Treatment
Patients with carotid artery disease should have their risk factors managed to reduce disease progression. This would include treating:
- Smoking.
- Diabetes.
- High blood pressure.
- High cholesterol.
- Poor diet
- Sedentary lifestyle.
Medical treatments should include the use of aspirin (or another anti-platelet agent). This thins the blood slightly and reduces the risk of clot forming on the atherosclerotic plaque.
Cholesterol medications are very important to both reduce new plaque formation and stabilise existing plaque, making it less likely to break off and travel to the brain.
Treatment of the plaque with surgery or stenting is indicated in certain circumstances.
Symptomatic patients (stroke, TIA) will benefit from surgery and this should be performed as soon as possible to prevent further symptoms developing.
Asymptomatic patients (where the stenosis has been identified but not yet caused symptoms) may benefit from surgery. This would depend on the patient’s age, general health, degree of stenosis or change in the stenosis. Careful assessment is required to weigh up the risk vs benefit in this group.
Carotid surgery (endarterectomy) is the process of removing the plaque from inside of the artery. The plaque builds up in the inner part of the blood vessel wall and this can be scrapped away from the artery leaving a smooth surface behind. The artery is then closed with an artificial patch to broaden it out and reduce the chance of any further narrowing developing.
Carotid stenting is an alternative to surgery and is recommended in patients who cannot have surgery due to other medical issues.
Related Information
Carotid Endarterectomy
Carotid Stenting
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