Carotid Stenting

Authors: Dr Peter Mitchell*
                            Dr Winston Chong *

What is carotid stenting?

Carotid stenting is when a small, expandable, thin wire device (called a stent) is placed into one of the main arteries that carries blood to the front part of the brain (carotid artery), as it has become partially blocked with abnormal thickening of the artery wall called ‘plaque’.

If the supply of blood to the brain is reduced, it can cause a stroke. The stent is placed in the artery, and then expanded to widen the artery to its normal size and smooth the inner surface to increase blood flow.

X-ray contrast medium (sometimes called a ‘dye’ or contrast agent – see Iodine-containing contrast medium(ICCM)) is injected into an artery to show the artery clearly on X-ray images or pictures displayed on a television screen. These X-ray images are used to guide and assist accurate placement of the stent (see Angiography).

Carotid stenting is an alternative treatment to surgery (endarterectomy) or medical therapy that might include treatment to thin the blood to stop it from clotting (anticoagulation), as well as lifestyle management. The procedure can be carried out while a patient is awake or under a general anaesthetic (asleep). Whether or not a general anaesthetic is used is decided by the doctor carrying out the procedure, based on how complex the procedure is and the patient’s medical condition.

Why would my doctor refer me to have this procedure?

If your doctor suspects you have a narrowing of the carotid artery from your history, symptoms and examination, you will be sent for a test to confirm whether narrowing of the artery exists. If significant narrowing is confirmed, you might be referred for carotid stenting to reduce the likelihood of a stroke, which is caused by a reduction of the blood supply to the brain.

Your doctor would choose carotid stenting as an alternative to surgery based on your particular medical condition and the reduced chance of complications.

How do I prepare for carotid stenting?

The most important preparation for carotid stenting is taking medications to thin the blood (called ‘antiplatelet therapy’) to reduce the likelihood of blood clots forming in the arteries. You will usually be required to take aspirin, as well as a prescription medication called Clopidogrel. This could start from up to 5 days before the procedure or it can be started closer to the time of the procedure using a larger dose. Your doctor or the hospital where you are having the procedure will advise you what medication you will need to take and when you are required to take it.

If a general anaesthetic is to be used, you will be required to fast (go without food or drink) usually for 6 hours before having the procedure. A shorter time of fasting will be required if the doctor has decided you will be awake for the procedure.

A clinic visit before having the procedure will be arranged to assess your condition, including as to whether a general anaesthetic is to be used.

You will be admitted to the hospital where you are having the procedure for at least one night afterwards, and you will need to make arrangements for this.

What happens during carotid stenting?

The procedure is carried out while you are lying on a bed in the angiography room of a hospital. You will first be given a local anaesthetic to numb the area (usually the groin) where the catheter is to be inserted or a general anaesthetic if the doctor decided this previously (see Angiography).

A catheter (a long, thin plastic tube) is inserted into an artery through a small cut in the groin, and placed in the carotid artery in the neck using X-ray images to guide placement of the catheter into its correct position. A thin wire will be inserted through the catheter, and passed across the narrow part in the artery that is to be widened by the stent (see picture above). Frequently, a device to reduce the risk of the procedure (embolic protection device) will be inserted over this wire. An embolic protection device is a tiny instrument that catches any blood clots or small particles of material blocking the artery that might break away during the procedure. Sometimes the blockage has to be slightly opened before the embolic protection device can pass through the narrow part, and before the stent is put in place.

A stent attached to a catheter is placed through the narrow part, and uncovered to open the stent. After the stent is in place, there might be a need to stretch and widen the stent using a small balloon inserted with another catheter. If an embolic protection device is used, it will be removed together with all of the catheters at the end of the procedure.

Usually, a closure device is used to quickly seal the small cut where the original catheter was inserted in the groin. This is to reduce bleeding from the antiplatelet therapy and blood thinning agents that are given during the procedure. After the procedure, it is very important to continue the antiplatelet drugs (aspirin and clopidogrel).

You will be admitted to a hospital ward or intensive care unit (ICU) for observation at least overnight, and it might be necessary to control your blood pressure.

Are there any after effects of carotid stenting?

Most people have no after effects following carotid stenting. If there is a complication, this is most often a stroke during the procedure, and the symptoms will depend on the size and the exact location of that stroke within the brain. You might have some discomfort in the region of the stent for a period of days to weeks, but this usually improves by itself. If you are concerned about any long-lasting after effects, contact the doctor at the hospital where the carotid stenting was carried out.

You will need to have an imaging procedure (usually computed tomography (CT) angiography) 3–6 months after having carotid stenting to check whether the artery has narrowed again.

How long does carotid stenting take?

Carotid stenting can be completed within 30 minutes or can take up to 2 hours if the artery to be stented is difficult to access.

What are the risks of carotid stenting?

There are risks with carotid stenting. The main risk is of causing stroke during the stenting procedure. This occurs in between 2% and 10% of all carotid stenting procedures carried out. The risk of using carotid stenting to widen the artery is similar to the risk of having surgery (carotid endarterectomy). Carotid stenting would only be recommended when doctors believe patients are less likely to be at risk than if they had surgery.

Other problems that can occur with the procedure are:

• Difficulties with the site in the groin where the catheter was inserted, such as haematoma (bruising) or pseudoaneurysm (outpouching of a blood-filled sac from the artery wall); and
• Dissection (separation of the layers of the artery wall). This can occur in the groin or in the carotid artery.

Contrast medium can be damaging to kidneys, particularly in people who already have poorly functioning kidneys. Occasionally, people can be allergic to the contrast material (See Iodine-containing contrast medium (ICCM)).

Occasionally, the artery that has been stented narrows again. This will be checked at the time the patient has follow-up imaging. If this occurs, the procedure can be repeated, and the area can be restretched with a balloon.

People should fully explore the benefits and risks before having this procedure. This can be done by asking the doctor who will carry out the procedure for material to read, and discussing the possibility of seeking a second opinion.

What are the benefits of carotid stenting?

The purpose of carotid stenting is to reduce your chance of stroke by increasing the supply of blood through the stented artery. This is considered by many to be more effective than surgery or medical therapy.

It is still unclear, based on the medical evidence, whether surgery or carotid stenting is generally better. Currently, it is believed that people having carotid stenting should be experiencing symptoms from a narrowed artery and be considered as having a higher than average risk from having surgery.

Carotid stenting avoids potential damage to nerves in the neck, such as the nerves involved with speech and swallowing, which can occur with surgery. The recovery period from an uncomplicated carotid stenting procedure would normally be quicker than uncomplicated surgery.

Who does carotid stenting?

There are a wide variety of doctors that now perform carotid stenting. This includes interventional neuroradiologists, interventional radiologists, vascular surgeons and cardiologists (specialist doctors). There are significant advantages in choosing a specialist doctor experienced in this procedure as complications, such as stroke are likely to be lower.

Where is carotid stenting done?

Carotid stenting is performed in the angiography suite of a most of public and private hospitals.

What happens after I have had my carotid stenting?

The specialist doctor who carried out the carotid stenting will tell you the outcome of the procedure immediately or as soon as possible after it is completed, and will send a full written report about the procedure to the doctor who referred you. Medical staff at the hospital where you are admitted after the procedure will advise you when you are recovered and can go home.

It is important you discuss the outcome of the procedure with the doctor who referred you, so they can explain what the outcome means for you. Your doctor will also discuss with you arrangements for the follow-up CT scan.

It is important that you contact the doctor who referred you if you have any symptoms that worry you after you are released from hospital.

*The author has no conflict of interest with this topic.

Page last modified on 26/7/2017.