Overview

Why is it necessary?

A carotid endarterectomy may be needed if one or both of your carotid arteries become narrowed because of a build-up of fatty deposits (plaque).

This is known as carotid artery disease or carotid artery stenosis, and it significantly increases your risk of having a stroke or a transient ischaemic attack (TIA).

Why carotid artery disease develops

Normal healthy arteries are elastic and smooth on the inside, allowing blood to easily flow through them.

As a person gets older, plaque can build up inside the arteries, making them narrower and stiffer. This process is called atherosclerosis.

As well as ageing, there are several other factors that can contribute to a build-up of plaque, including:

• a high-fat diet
• high blood pressure (hypertension)
• diabetes
• smoking

Carotid artery disease and stroke

There are 2 ways a stroke or TIA could occur if the flow of blood through your carotid arteries becomes blocked or restricted:

• an ischaemic stroke –if the carotid artery is completely blocked and limits the blood supply to your brain
• an embolic stroke – if a blood clot forms on the roughened surface of the carotid artery and breaks off,it may block one or more arteries in the brain

Diagnosing carotid artery disease

Carotid artery disease is usually diagnosed if a person has the symptoms of a stroke or TIA, such as the face drooping on one side, numbness or weakness in the arms or legs, speech problems, or a loss of vision in one eye.

Sometimes it's diagnosed if you're having tests for another reason and the doctor testing you notices your arteries are narrowed. This is called an asymptomatic carotid stenosis.

If you've recently had a stroke or a TIA, you'll be referred for some brain imaging tests. This allows the blood supply to your brain to be checked and any narrowing in your carotid arteries to be diagnosed.

Several tests can be used to examine your carotid arteries and find out how much plaque has built up inside them. These include:

• duplex ultrasound scan –sound waves are used to produce an image of your blood vessels and measure the blood flow through them; it can also show how narrow your blood vessels are
• computerised tomography (CT) scan–a series of X-rays are taken at slightly different angles, and a computer assembles the images to create a detailed picture of the inside of your body
• computed tomographic angiogram (CTA) –a special dye is injected into a vein and a CT machine is used to take X-rays to build up a picture of your neck arteries
• magnetic resonance angiography (MRA) –a magnetic field and radio waves are used to produce images of your arteries and the blood flow within them

You'll usually have an ultrasound scan first to check if there's any narrowing in your arteries and determine whether it's severe enough for you to benefit from having surgery.

If your arteries are narrowed, you may need to have further tests to confirm the diagnosis, such as a CTA or MRA.

Grading narrowed arteries

If tests indicate your carotid arteries are narrowed, the severity of the narrowing (stenosis) will be graded to determine if you need surgery.

In the UK, the most common grading system used is the North American Symptomatic Carotid Endarterectomy Trial (NASCET) scale. 

The scale has three categories:

• minor - 0-49% narrowed
• moderate - 50-69% narrowed
• severe - 70-99% blocked

When is surgery recommended

The National Institute for Health and Care Excellence (NICE) recommends that people who have had a stroke or TIA and have a moderate or severe stenosis should have a carotid endarterectomy.

You should be assessed within a week of the start of your stroke or TIA symptoms.

The operation will ideally be carried out within 2 weeks of when your symptoms started.

It's crucial to get medical advice as soon as possible if you develop the symptoms of a stroke or TIA.

Having surgery gives the best chance of preventing a further stroke if it's performed as soon as possible.

Surgery is sometimes recommended for people who haven't previously had a stroke or a TIA, but are found to have severe stenosis.

Surgery isn't recommended in cases where there's minor stenosis (less than 50%).

This is because surgery is most beneficial for people with moderate and severe stenosis (more than 50%).

The maximum benefit is seen in those with severe stenosis (70 to 99%).

A carotid endarterectomy isn't of any benefit for people with a complete blockage of their carotid artery.

Getting Ready

Before being admitted for surgery, you'll have a careful pre-operative assessment.

The assessment will usually be carried out at a hospital pre-assessment clinic a few days before you're due to have the procedure.

In some cases, you'll be asked to attend the pre-assessment clinic on the day of the operation.

Alternatively, you may be seen at a specialist clinic if you've recently had a stroke or transient ischaemic attack (TIA).

You'll have tests to check the health of your arteries, and you may be admitted for surgery immediately if your carotid arteries are found to be severely narrowed.

Pre-admission clinic

You'll have a physical examination and be asked about your medical history at a pre-admission clinic. Any further tests or examinations needed will also be carried out at this time.

The pre-admission clinic is a good opportunity for you to ask your treatment team about the procedure, although you can discuss any concerns you may have at any time.

If you're taking any medication (prescribed or otherwise), it would be useful to bring it with you to the pre-admission clinic so the details can be noted.

You'll be asked whether you've had anaesthetic (painkilling medication) in the past and whether you experienced any problems or side effects, such as feeling sick.

You'll also be asked whether you're allergic to anything to avoid a reaction to any medication you may need during your treatment.

Your treatment team will ask you about your teeth, including whether you wear dentures, have caps or a plate.

This is because during the operation you may need to have a tube put down your throat to help you breathe, and loose teeth could be dangerous.

Preparing for surgery

Before having a carotid endarterectomy, your surgeon will discuss how you should prepare.

They may give you the following advice:

• stop smoking – smoking increases your risk of developing a chest infection, can delay healing, and increase your risk of developing a blood clot
• watch your weight –if you're overweight, losing weight will be recommended, but as strenuous exercise could be dangerous, you'll need to do this by dieting; your GP will be able to advise you about how to lose weight
• think positive – a positive mental attitude can help you deal with the stress of surgery and aid your recovery

Read more about preparing for surgery.

How is it performed?

A carotid endarterectomy will either be carried out under general or local anaesthesia.

Anaesthetic

Anaesthetic is painkilling medication that allows surgery to take place without a patient feeling pain or discomfort.

If you have a general anaesthetic, you'll be asleep throughout the procedure.

You'll remain conscious if you have a local anaesthetic, but the area on your neck will be numbed so you can't feel any pain.

Studies comparing the results of carotid endarterectomies found no difference between the two types of anaesthetic.

It will be up to you, your surgeon and your anaesthetist (specialist in anaesthesia) to decide which type of anaesthetic to use.

Your surgeon may prefer to use local anaesthetic so you remain conscious during the operation.

This allows them to monitor your brain's reaction to the decreased blood supply throughout the procedure.

The procedure

A carotid endarterectomy usually takes one to two hours to perform. If both of your carotid arteries need to be unblocked, two separate procedures will be carried out. One side will be done first and the second side will be done a few weeks later.

Once you're unconscious or the area has been numbed, your neck will be cleaned with antiseptic to stop bacteria getting into the wound.

If necessary, the area may also be shaved. A small cut will then be made to allow the surgeon to access your carotid artery.

During the procedure, your surgeon will decide whether to use a temporary shunt to maintain adequate blood flow to the brain.

A shunt is a small plastic tube that can be used to divert blood around the section of the carotid artery being operated on.

The decision to use a shunt is based on surgeon preference and the results of brain blood flow monitoring during the operation.

When the surgeon has access to the carotid artery, the artery is clamped to stop blood flowing through it and an opening is made across the length of the narrowing. If a shunt is to be used, it will be inserted now.

The surgeon will then remove the inner lining of the narrowed section of artery, along with any fatty deposits (plaque) that have built up.

Once the narrowing has been removed, the opening in the artery will then either be closed with stitches or a special patch.

Most surgeons in the UK use a patch, but the choice is down to what the surgeon prefers.

Your surgeon will then check for any bleeding. The cut in your neck will be closed after any bleeding has stopped.

A small tube (drain) may be left in the wound to drain away any blood that might build up after the operation. This is usually removed the following day.

After the procedure

After the operation, you'll usually be moved to the recovery area of the operating theatre, where your health will be monitored.

Recovery

After a carotid endarterectomy, you'll usually be moved to the recovery area of the operating theatre.

People who need more close observation after surgery, usually because they have high blood pressure, may be moved to a high dependency unit (HDU).

After surgery, your breathing and heart rate will be monitored to ensure you're recovering well.

You may have some discomfort in your neck around where the incision was made. This can usually be controlled with painkillers.

You may also experience numbness around the wound, which should disappear after a while.

Most people are able to eat and drink a few hours after having surgery. You'll usually be able to leave hospital and return home within 48 hours.

Wound care

The wound on your neck will be closed with stitches, which may need to be removed at a later date.

Your surgeon will be able to advise you about this. Sometimes dissolvable stitches or skin glue are used instead.

Your surgeon will also be able to give you advice about caring for your wound. This will usually be a simple matter of keeping it clean using mild soap and warm water.

You may be left with a small scar running from the angle of your jaw to the top of your breastbone.

The scar is usually about 7-10cm long and fades to a fine line after two or three months.

Driving

Your GP will be able to advise you about when it's safe to drive after surgery – usually when you can safely carry out an emergency stop. For most people, this is between two to three weeks after the operation.

If you've had a stroke or transient ischaemic attack (TIA), you won't be allowed to drive for a month afterwards.

If you've fully recovered, you don't need to inform the DVLA unless you drive a lorry or a bus for a living.

Work and exercise

Most people are able to return to work 3 to 4 weeks after having a carotid endarterectomy. Your surgeon or GP will be able to advise you further about returning to work.

Being active can help your recovery, but you shouldn't overdo it. Your surgeon can advise you about how much exercise you can do, and may recommend that you limit physical activity for a few weeks after having surgery.

This includes manual labour and playing sports. If your job involves manual labour, you should only perform light duties until you have fully recovered.

Risks

As with all types of surgery, there are risks associated with having a carotid endarterectomy.

The two main risks are:

• stroke – the risk of stroke is around 2%, although this may be higher in people who had a stroke before the operation
• death – there's a less than 1% risk of death, which can occur as a result of complications such as a stroke or heart attack

Most strokes that occur after carotid endarterectomy are caused by an artery in the brain becoming blocked during the early postoperative period, or because there's some bleeding into the brain tissue.

This may happen if the procedure causes a blood clot to move and block an artery. Your surgical and anaesthetic team will do all they can to prevent this.

Other complications

Other possible complications after having a carotid endarterectomy include:

• pain or numbness at the wound site – this is temporary and can be treated with painkillers
• bleeding at the site of the wound
• wound infection – the wound where the incision was made can get infected; this affects less than 1% of people and is easily treated with antibiotics
• nerve damage –this can cause a hoarse voice and weakness or numbness on the side of your face; it affects around 4% of people, but is usually temporary and disappears within a month
• narrowing of the carotid artery again – this is called restenosis; further surgery is required in about 2-4% of people

Your surgeon should explain the risks associated with a carotid endarterectomy before you have the procedure.

Ask them to clarify anything you're not sure about and answer any concerns you have.

Increased risk

Factors that increase your risk of experiencing complications because of a carotid endarterectomy include:

• your age – the risk increases as you get older
• whether you smoke
• having previously had a stroke or transient ischaemic attack (TIA) – the risk depends on the severity of the stroke or TIA, how well you recovered, and how recently it occurred
• whether you have a blockage in your other carotid artery as well
• whether you have other health conditions – such as cancer, heart disease, high blood pressure (hypertension) or diabetes

Alternatives

Carotid endarterectomy is the main treatment for narrowing of the carotid arteries as it's very effective.

But, there's also an alternative procedure called carotid artery stent placement, or stenting.

Carotid artery stent placement

Carotid artery stent placement is less invasive than a carotid endarterectomy because it doesn't involve a cut being made in the neck.

Stenting is carried out under local anaesthetic and involves a narrow flexible tube called a catheter being inserted into an artery in your groin.

It's then threaded up into the carotid artery using X-rays to guide it into place.

A small balloon at the end of the catheter is inflated to around 5mm at the site of the narrowed artery, and a small mesh cylinder called a stent is then inserted.

The balloon will be deflated and removed, leaving the stent in place to keep the artery open and allow blood to flow through it.

After the procedure, you'll need to lie flat and keep still for about an hour to prevent any bleeding from the artery.

You'll need to stay in hospital overnight, but will be able to return home the next day.

Like carotid endarterectomy, there are some risks associated with stenting.

The risk of having another stroke or dying is slightly higher than after carotid endarterectomy, especially when the procedure is performed soon after symptoms appear.

But the long-term outcomes from a successful procedure are no different from a carotid endarterectomy.

The decision about which procedure you'll have will be made based on your own personal wishes, your overall fitness, and an assessment of your clinical history. One major factor is how long it's been since your most recent symptom.

NICE guidelines

The National Institute for Health and Care Excellence (NICE) has confirmed stenting is a safe procedure and has good short-term results.

Evidence suggests a successful stent procedure has the same long-term risks of a stroke as carotid endarterectomy.

NICE advises that, provided the risks of stenting are judged similar to those after surgery, it's safe to offer this alternative.

Read the NICE guidance on carotid artery stent replacement for symptomatic extracranial carotid stenosis.