Focus on: Stroke and carotid artery disease
Carotid artery disease is a common cause of stroke. Senior cardiac nurse Doireann Maddock talks to Professor Hugh Markus about the disease and its potentially devastating effects.
What is carotid artery disease?
The carotid arteries supply oxygenated blood to the large front part of the brain. This part of the brain controls thought, speech and personality as well as our sensory (our ability to feel) and motor (our ability to move) functions. Carotid artery disease is the name given to narrowing (stenosis) of one or both of the carotid arteries, located at the front of your neck.
The underlying cause of carotid artery disease is usually atherosclerosis (the build-up of fibrous and fatty material inside the arteries), in this case in the carotids. Over time, this material forms a plaque. This builds gradually over the years, resulting in a bigger plaque and the progressive narrowing of the arteries. As arteries narrow, this can restrict blood flow. The picture above illustrates a narrowing in the left carotid artery of a person’s neck.
What are the possible effects of carotid artery disease?
Carotid artery disease is a major cause of stroke, accounting for about 20 in 100 of all cases. It is also more common in older people who’ve had a stroke. There are about 152,000 strokes in the UK every year and, currently, about 1.2 million people in the UK living with the after effects. If you have carotid artery disease, atherosclerosis may develop in other arteries throughout the body. You will be advised to take great care in minimising your risk factors as there is an increased chance that you may develop narrowing in your coronary arteries (coronary heart disease) or narrowing in the arteries in your legs caused by peripheral arterial disease (PAD).
Managing your risk
To reduce your risk of carotid artery disease and stroke, address any modifiable risk factors you may have (meaning the ones that you can control).
Risk factors that you can do something about include keeping blood pressure and cholesterol at healthy levels, being as active as possible, maintaining a healthy body weight and, if you smoke, giving it up.
If you have diabetes, aim for good control of your blood sugar levels.
How would I know if I had it?
It’s possible to have carotid artery disease and no symptoms. Usually, it is diagnosed after someone has a stroke or a transient ischaemic attack (TIA) – sometimes called a mini-stroke. The symptoms of stroke and TIA are identical and can include weakness in your face or arms and speech problems.
The symptoms that you get depend on which blood vessels are blocked and which part of the brain they supply with oxygen. Both are medical emergencies and if you or someone you are with experiences them, call 999 immediately.
Carotid artery disease may also be discovered during a health check if the doctor listens to your carotid arteries and hears a whooshing sound (called a ‘carotid bruit’). This noise may occur when there is narrowing present, but it’s not always heard even if you do have carotid artery disease. This check is something a GP may do if they are concerned about your risk factors for stroke. If a carotid bruit is detected, your GP will refer you for a scan.
Carotid artery disease may also be picked up when having other tests or scans in the neck area. There are several types of scan for carotid artery disease. The most common is an ultrasound (sometimes called a carotid doppler). This is a simple and painless procedure where a probe is passed over the carotid arteries to scan and make pictures of them. It can then be determined if there is any narrowing present. This is the easiest thing to do but you can also do scans using computerised tomography (CT) or magnetic resonance imaging (MRI). All of these scans are good at detecting carotid artery disease.
Find out more about imaging techniques.
How does carotid artery disease cause a stroke or TIA?
There are three main ways in which this can happen. The first is when plaque narrows and completely blocks a carotid artery (total occlusion); the second is by thrombosis, which is when an area of plaque ruptures, damaging the lining of the artery. Blood then begins to clot over it and this clot (called a thrombosis) causes a blockage. The third way, which is the most significant because it is the mechanism that causes most strokes, is by an embolism where a clot that forms on the plaque breaks off and passes in the blood to the brain, where it blocks a brain blood vessel. All of these cause an interruption in the blood flow to the brain and can result in symptoms of stroke or TIA.
What is the potential impact of a stroke or TIA?
"There are about 152,000 strokes in the UK every year and about 1.2 million people in the UK living with the after effects"
Stroke and TIA initially present in the same way. The difference is that symptoms of a TIA resolve fully within 24 hours, and therefore it does not cause permanent damage. A stroke can damage both the mind and body and affects people in different ways depending on the part of the brain that has been damaged. Their face may drop on one side, or they may have weakness in their arms or problems with speech or language.
About 80 per cent of stroke survivors experience movement problems, 30 per cent have some difficulty with speaking or understanding what others are saying, and at least 40 per cent initially have some difficulty swallowing.
Problems with memory, thinking and understanding are also common and most people who have had a stroke are affected by this in some way. Effects can vary from not being able to concentrate for as long as before to more severe problems such as being completely unable to plan your day. The symptoms that you get depend on which blood vessel becomes blocked and which part of the brain that vessel supplies with oxygen.
Both stroke and TIA are important warning signs that the risk of another stroke is increased, particularly over the following few days and weeks. Therefore, even if the symptoms quickly disappear, you should still let your doctor know.
Stroke symptoms: act FAST
A stroke is a medical emergency, and it’s vital to recognise the signs and symptoms so you can act fast and get help. Time is of the essence because the sooner a person receives treatment for a stroke, the less damage is likely to happen.
The main signs and symptoms of stroke can be remembered with the word FAST: Face, Arms, Speech, Time.
Face – the person’s face may have dropped on one side, affecting their eye or mouth. They may have problems smiling.
Arms – weakness or numbness in the arms may mean the person has difficulty lifting one or both arms and keeping them there.
Speech – words may sound garbled or the person may not be able to speak at all, even though they are awake.
Time – call 999 immediately if you see any of these signs or symptoms.
How are stroke and TIA treated?
If you get symptoms such as facial weakness, arm weakness or speech problems, call 999 straight away.
With stroke and TIA there are two main things to consider; firstly, you have to treat the acute symptoms and secondly, you have to prevent further strokes or TIAs.
If the patient is admitted to hospital within four and a half hours of the stroke then they may be suitable for clot-busting drugs to dissolve the clot that is blocking the brain artery and causing the symptoms. All patients who have had a stroke should be admitted to a specialised stroke unit and given supportive care; this has been shown to reduce death rates by about a quarter. After that, there are things that can be done to reduce the risk of another stroke or TIA. You may be given antiplatelet drugs like aspirin or clopidogrel, which thin the blood and reduce the risk of future clots developing.
"A stroke affects people in different ways depending on the part of the brain damaged"
When there is significant narrowing in the carotid artery, doctors will intervene and remove whatever is causing it – for example, a blood clot or build-up of plaque. This is achieved by performing an operation called carotid endarterectomy, where you open up the artery and remove the blockage, before sewing it back up again. It’s a standard procedure now with a relatively quick recovery time and we would carry it out as soon as possible for patients who have had a TIA or minor stroke. With a major stroke, we may wait until the person has stabilised because giving them an anaesthetic could make things worse.
Another option to treat the narrowing is carotid artery stent placement (often known as stenting). This procedure is less invasive than a carotid endarterectomy as it does not involve open surgery of the neck and is performed under a local anaesthetic. However, trials to date suggest that stenting has a slightly higher risk of stroke during the procedure, so carotid endarterectomy is the preferred method. Longer term, other risk factors such as high blood pressure or cholesterol will also need to be addressed.
What about if I have carotid artery disease but no symptoms?
When someone has carotid artery disease but without any symptoms, medical drug treatment alone may be sufficient. If these patients don’t have an operation, the risk of having a stroke in a year is only about 1 per cent. This is compared with a 20 to 30 per cent risk in the first year for a person who has had symptoms such as a TIA and has a tight stenosis.
What are the chances of recovery?
Lots of people recover well from a stroke. It depends partly on the severity of the stroke and whether the person has been treated with clot-busting drugs. About 20 per cent of patients die in the first three months after a stroke and a significant number become disabled in some way. An increasing number of people are making good recoveries, though.
"Lots of people recover well from a stroke"
Having acute stroke units has made a big difference. We can admit patients to these and give them clot-busting treatments very quickly. There is research showing that if you put people in acute stroke units, the death rate drops by about 25 per cent. In London, all stroke patients are now admitted to one of eight acute stroke units and this has really improved outcomes for them. This way of treating stroke patients is being spread throughout the country.
Because we know that giving clot-busting treatments quickly is important to improve the outcome for patients, it’s critical to remember to call 999 immediately if you or anyone you know experiences symptoms such as facial or arm weakness or problems with speech.
Read one man's story of stroke recovery.
Visit the Stroke Association's website.