Carotid Artery Stenosis

How carotid stenosis causes strokes

The carotid arteries run up each side of the neck and divide into internal and external branches. The internal carotid supplies most of the front and middle of the brain and the eye. Plaque tends to build up at the fork (bifurcation).

Stroke risk comes mainly from embolism, not complete blockage: the surface of a plaque can crack, a clot forms on it, and fragments travel to the brain. Less often, severe narrowing reduces blood flow.

Risk factors

• age over 65
• smoking
• high blood pressure
• high cholesterol
• diabetes
• obesity and inactivity
• coronary or peripheral artery disease
• family history of atherosclerosis
• previous neck radiotherapy

Symptoms

Most people with carotid stenosis have no symptoms. Symptoms occur when a stroke or transient ischemic attack happens. Use BE FAST:

• Balance: sudden loss of balance or coordination
• Eyes: sudden loss of vision in one eye, or blurred vision
• Face: drooping on one side
• Arms: weakness or numbness on one side
• Speech: slurred or confused speech, or trouble understanding
• Time: call emergency services immediately

Amaurosis fugax, a temporary blackout of vision in one eye lasting seconds to minutes, is a classic warning of carotid disease on the same side.

Symptomatic vs asymptomatic stenosis

Diagnosis

• Listening with a stethoscope: a whooshing sound called a bruit may be heard, but it is unreliable
• Carotid duplex ultrasound: the first test. It shows plaque and measures how fast blood flows through the narrowing, which estimates the percentage of stenosis
• CT angiography or MR angiography: confirm the degree of narrowing and show the arteries into the brain
• Brain imaging (CT or MRI) after a TIA or stroke

The USPSTF does not recommend routine screening of people without symptoms, because false positives can lead to unnecessary procedures.

Treatment

Best medical therapy (for everyone)

• Antiplatelet medicine: aspirin, clopidogrel, or for a short period after a TIA, both together
• Statin: high-intensity, to lower LDL cholesterol and stabilize plaque
• Blood pressure control: typically below 130/80 mmHg
• Diabetes control
• Stopping smoking
• Exercise, a Mediterranean-style diet and weight management

Carotid endarterectomy

A surgeon opens the artery in the neck and removes the plaque. It is recommended for:

• symptomatic stenosis of 70% to 99%, and considered for 50% to 69%
• selected asymptomatic patients with severe narrowing, low surgical risk and good life expectancy

Benefit is greatest when surgery is done within 2 weeks of a TIA or minor stroke. Risks include stroke, heart attack, nerve injury affecting swallowing or tongue movement, and bleeding.

Carotid stenting

A stent is placed through a catheter, from the groin, wrist, or directly through the neck (transcarotid artery revascularization, TCAR). It is an option for people at high surgical risk or with anatomy unsuitable for surgery, such as previous neck surgery or radiation.

Outlook

With modern medical therapy, many people with asymptomatic stenosis have a low stroke risk. Symptomatic stenosis carries a high early risk, which falls substantially after prompt treatment. Carotid disease signals widespread atherosclerosis, so heart attack prevention is just as important.

Frequently asked questions

What are the symptoms of carotid artery stenosis?

Usually none until a TIA or stroke occurs. Warning signs include sudden one-sided weakness or numbness, facial drooping, slurred speech, and temporary loss of vision in one eye. Any of these needs emergency assessment, even if they pass quickly.

How is carotid stenosis diagnosed?

A carotid duplex ultrasound of the neck is the first test. It shows plaque and estimates the degree of narrowing from blood flow speed. CT or MR angiography may confirm the findings and help plan treatment.

When is surgery needed for carotid stenosis?

Surgery or stenting is recommended for significant narrowing (usually 70% or more, sometimes 50% or more) that has caused a TIA or stroke, ideally within 2 weeks. For narrowing without symptoms, it is considered only in selected people.

Can carotid stenosis be reversed?

Plaque does not usually disappear, but statins, blood pressure control, quitting smoking and antiplatelet medicines can stabilize it, slow progression and substantially lower stroke risk. Endarterectomy removes plaque directly in selected patients.

What is a carotid endarterectomy?

It is an operation in which a surgeon makes an incision in the neck, opens the carotid artery and removes the plaque. It reduces the risk of future stroke in people with significant narrowing, especially after a TIA or minor stroke.