Anaesthetic is painkilling medication that allows surgery to take place without you feeling pain or discomfort.
If you have a general anaesthetic, you'll be unconscious 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 2 types of anaesthetic.
It'll 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.
A carotid endarterectomy usually takes 1 to 2 hours to perform. If both of your carotid arteries need to be unblocked, 2 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 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 diverts 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 accessed the carotid artery, they'll clamp it to stop blood flowing through it and make an opening 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 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 check for bleeding and close the cut in your neck 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.
Read more about recovering from a carotid endarterectomy.