Asymptomatic carotid disease
The carotid arteries are very important blood vessels which are situated in your neck. They start off as a single artery (Common carotid) inside the chest and travel deep behind the collar bone into the neck where they divide like a fork into two branches roughly at the level of the “Adam’s apple” on each side of the neck. One branch called the internal carotid travels straight to the inside of the skull to supply blood to the brain while the other , the external carotid, divides into a number of smaller branches to supply blood to the face, the tongue the pharynx, the larynx and so on. This fork like division is called the “carotid bifurcation” and is a very important site in the body where hardening of the arteries can occur by a process called atheromatous plaque formation. This plaque can break off and then travel to your brain to block important arteries inside the skull which can lead to a stroke. The plaque can also severely narrow the artery in the neck and reduce the overall blood flow to the brain which can also lead to a stroke.
What should you do?
If you are concerned you may have diseased carotid arteries, discuss this with your local doctor. If your doctor is concerned he would usually check your blood pressure, your cholesterol, diabetes check and advise you on correct life style including exercise and weight reduction. Routine blood tests will be done and if he thinks your carotid arteries are at risk he would usually order a carotid ultrasound study (duplex scan). When performed by correctly trained personnel (most commonly found in dedicated vascular diagnostic laboratories) the duplex scan is a very accurate method to define the extent and significance of carotid bifurcation disease and vascular surgeons who operate on neck arteries may rely solely on this information if they are confident in the imaging centre’s expertise in neck artery duplex scanning. Sometimes more complex investigations are also required to examine other arteries.
You should definitely see your doctor if you ever experience warning symptoms which are termed transient ischaemic attacks (TIA) or mini-strokes. Examples are sudden temporary weakness or numbness in an arm or a leg or the whole side of the body or sudden visual loss or disturbance. Even less definite symptoms such as dizziness or unsteadiness should be discussed with your doctor.
If you are already known to have diseased arteries anywhere in your body (e.g. the neck, the heart, the legs) you must control the factors which will worsen the process: stop smoking; control blood pressure; control diabetes, control your cholesterol; control your weight and exercise regularly. You should discuss medications related to all these factors including medications which can reduce the “stickiness” of your blood with your doctor. This needs to be done whether you require surgery or not.
Major studies performed in the early 1990’s both in Europe and North America conclusively proved that removal of the carotid bifurcation plaque by surgery ( Carotid Endarterectomy) significantly lowers the chance of stroke when there is a significant amount of disease present and provided the surgery is performed by specialist surgeons who have a low risk rate from the surgery. As with any intervention however there is a risk to the organ which is being operated upon and therefore a rare risk of carotid surgery is stroke or even death. However surgery is only carried out when those risks are much lower than the risks of not intervening.
The surgery involves a longitudinal or curved incision down the side of the neck to allow the surgeon to isolate the carotid artery, temporarily clamp it, open it, shell out the disease and then close up the artery with a suture. The surgeon may use a piece of synthetic material or a piece of your own vein as a “patch” to sow up the artery so that it is not narrowed by the suture. The surgery can be performed under general anaesthesia or with you awake and the neck made numb by local anaesthetic strategically placed to temporarily block the pain nerves. Usually you only require 1-2 nights in hospital. You usually experience numbness in that side of your neck because some fine nerves have to be cut but this often corrects itself in a few months. Sometimes hoarseness can occur but this is almost invariably temporary.
Another but less proven way to intervene on carotid disease is to place a stent inside the diseased artery. This is a fine metal scaffold designed to keep the artery open and to trap any plaque. This requires operators who have recognised experience with the technique. It carries similar risks to surgery when performed by qualified interventionalists and is usually confined to patients who are not suitable for surgery. It usually performed under local anaesthesia with the stent being introduced through the artery in the groin and then passed up to the neck artery. It requires use of special X-ray equipment and injected dye during the procedure to show the arteries to the operator as the procedure is being performed.
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