Carotid Artery Disease

The main supply of blood to the brain is carried by the carotid arteries. The carotid arteries branch off from the aorta (the largest artery in the body) a short distance from the heart, and extend upward through the neck carrying oxygen-rich blood to the brain.

There are four carotid arteries: the right and left internal carotid arteries and the right and left external carotid arteries. One pair (external and internal) is located on each side of the neck. Just as a pulse can be felt in the wrists, a pulse can also be felt on either side of the neck over the carotid arteries.

Because the carotid arteries deliver blood to the brain, carotid artery disease can have serious implications by reducing the flow of oxygen to the brain. The brain needs a constant supply of oxygen in order to function. Even a brief interruption in blood supply can cause problems. Brain cells begin to die after just a few minutes without blood or oxygen. If the narrowing of the carotid arteries becomes severe enough to block blood flow, or a piece of atherosclerotic plaque breaks off and obstructs blood flow to the brain, a stroke may occur.

Atherosclerosis is the most common cause of carotid artery disease. It is unknown exactly how atherosclerosis begins or what causes it. Atherosclerosis is a slow, progressive, vascular disease that may start as early as childhood. However, the disease has the potential to progress rapidly. It is generally characterized by the accumulation of fatty deposits along the innermost layer of the arteries. If the disease process progresses, plaque formation may take place. Plaque is made up of deposits of smooth muscle cells, fatty substances, cholesterol, calcium, and cellular waste products. This thickening narrows the arteries and can decrease blood flow or completely block the flow of blood to the brain.

Risk factors associated with atherosclerosis include:

• Older age
• Male
• Family history
• Race or ethnicity
• Genetic factors
• Hyperlipidemia (elevated fats in the blood)
• Hypertension (high blood pressure)
• Diabetes
• Obesity
• Diet high in saturated fat
• Life style (smoking, lack of exercise)

A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases have different risk factors.

Although these risk factors increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors. Knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.

Carotid artery disease may be asymptomatic (without symptoms) or symptomatic (with symptoms). Asymptomatic carotid disease is the presence of a significant amount of atherosclerotic build-up without obstructing enough blood flow to cause symptoms. However, a sufficiently tight stenosis will not always cause symptoms. Symptomatic carotid artery disease may result in either a transient ischemic attack (TIA) and/or a stroke (brain attack).

A transient ischemic attack (TIA) is a sudden or a temporary loss of blood flow to an area of the brain, usually lasting a few minutes to one hour. Symptoms usually go away entirely within 24 hours, with complete recovery. Symptoms of a TIA may include, but are not limited to, the following:

• Sudden weakness or clumsiness of an arm and/or leg on one side of the body
• Sudden paralysis (inability to move) of an arm and/or leg on one side of the body
• Loss of coordination or movement
• Confusion, dizziness, fainting, and/or headache
• Numbness or loss of sensation (feeling) in the face
• Numbness or loss of sensation in an arm and/or leg
• Temporary loss of vision or blurred vision
• Inability to speak clearly or slurred speech

TIA may be related to severe narrowing or blockage or from small pieces of an atherosclerotic plaque breaking off, traveling through the bloodstream, and lodging in small blood vessels in the brain. With TIA, there is rarely permanent brain damage.

Call for medical help immediately if you suspect a person is having a TIA, as it may be a warning sign that a stroke is about to occur. Not all strokes, however, are preceded by TIAs.

Stroke is another indicator of carotid artery disease. The symptoms of a stroke are the same as for a TIA. A stroke is loss of blood flow (ischemia) to the brain that continues long enough to cause permanent brain damage. Brain cells begin to die after just a few minutes without oxygen. The area of dead cells in tissues is called an infarct.

The area of the brain that suffered the loss of blood flow will determine what the physical or mental disability may be. This may include impaired ability with movement, speech, thinking and memory, bowel and bladder function, eating, emotional control, and other vital body functions. Recovery from the specific ability affected depends on the size and location of the stroke. A stroke may result in problems such as weakness in an arm or leg or may cause paralysis, loss of speech, or even death.

The symptoms of carotid artery disease may resemble other medical conditions or problems. Always consult your physician for a diagnosis.