Carotid artery disease: narrowed neck arteries and stroke risk explained

What is carotid artery disease?

You have two carotid arteries, one on each side of your neck. You can feel them pulsing gently if you place your fingers either side of your windpipe. These arteries carry the majority of the blood supply to the brain, so keeping them healthy is critical to protecting your brain.

Carotid artery disease is the narrowing (stenosis) of these arteries caused by atherosclerosis: the gradual build-up of fatty plaque inside the artery wall. The same process causes heart disease and peripheral arterial disease. In fact, carotid disease is an important marker that atherosclerosis is present throughout the body.

The danger of carotid disease is not usually the narrowing itself restricting blood flow. The greater danger is that the surface of the plaque can rupture, and small fragments of plaque or blood clot can break off and travel up into the brain, blocking a smaller artery and causing a stroke or transient ischaemic attack (TIA).

Recognising a stroke or TIA: act FAST

The symptoms of carotid disease are the symptoms of a TIA or stroke. A TIA (transient ischaemic attack, sometimes called a mini-stroke) produces the same symptoms as a stroke but they resolve, usually within minutes to an hour. A TIA must never be ignored: it is a serious warning that a major stroke may follow, sometimes within days.

Carotid disease specifically may also cause amaurosis fugax: a sudden, painless loss of vision in one eye, often described as a curtain or shutter coming down. This happens when a fragment travels to the artery supplying the eye. It is a form of TIA and requires the same urgent attention.

Symptomatic versus asymptomatic disease

Carotid disease is divided into two important categories, because they are managed very differently:

• Symptomatic carotid disease: the narrowing has already caused a TIA, stroke or amaurosis fugax. These patients are at high risk of a further stroke and benefit most from prompt treatment
• Asymptomatic carotid disease: the narrowing is found incidentally, before any symptoms, often on a scan done for another reason or after a neck bruit (a sound heard through a stethoscope) is detected. The risk of stroke is lower, and treatment is more individualised

How carotid disease is diagnosed

The first-line test is a carotid duplex ultrasound: a painless scan of the neck that measures the degree of narrowing and assesses the characteristics of the plaque. It is quick, safe and highly accurate.

When intervention is being considered, or when ultrasound findings need confirmation, a CT angiogram or MR angiogram provides detailed images of the carotid arteries from the chest up into the brain. These also assess the brain itself for any areas of previous stroke.

The degree of narrowing is expressed as a percentage. This percentage, combined with whether the disease is symptomatic, determines the best treatment.

Best medical therapy: the foundation for everyone

Every patient with carotid disease, whether or not they need a procedure, should receive best medical therapy. This is the foundation of stroke prevention and, for many people with asymptomatic disease, is the only treatment needed:

• Antiplatelet medication (such as aspirin or clopidogrel) to reduce the tendency of clots to form on the plaque surface
• High-intensity statin therapy to lower cholesterol, stabilise the plaque and reduce stroke and heart attack risk
• Blood pressure control to reduce the stress on the artery walls
• Stopping smoking, which is the single most important lifestyle change
• Diabetes control and a healthy diet and exercise pattern

Modern best medical therapy has improved so much that the stroke risk from asymptomatic carotid disease is now considerably lower than it was decades ago, around 1% per year. This is an important part of why the decision to operate on asymptomatic disease is carefully individualised.

Surgery and procedures for carotid disease

How the decision to treat is made

Choosing the right treatment depends on several factors considered together: whether the disease is symptomatic, the degree of narrowing, your overall fitness and life expectancy, the anatomy of the artery, and your own preferences after a full discussion of the risks and benefits.

For symptomatic disease with significant narrowing, the priority is prompt treatment, ideally carotid endarterectomy within two weeks, to prevent a further stroke. For asymptomatic disease, best medical therapy is the starting point, with surgery considered for fit patients who have severe narrowing and certain high-risk features that increase their individual stroke risk, such as evidence of silent strokes on brain imaging, particular plaque characteristics, or documented progression of the narrowing over time.

Carotid disease and your whole body

Finding carotid disease is an important signal that atherosclerosis is present elsewhere in your arteries. People with carotid disease have a raised risk of heart attack and of disease in the leg arteries. The best medical therapy used to protect the brain also protects the heart and the rest of the circulation, which is why optimising it matters so much, regardless of whether you need a procedure.

What to do next

If you have had any stroke or TIA symptoms, this is an emergency: call 999 immediately. Do not wait.

If you have been found to have carotid narrowing and want a specialist opinion on whether intervention is appropriate for you, or you want a review of your stroke prevention plan, a private vascular consultation can provide a prompt assessment including duplex ultrasound and a clear, individualised discussion of your options.