What are the carotid arteries?
The carotid arteries are the blood vessels that carry oxygen-rich blood away from the heart to the head and brain. Located on each side of the neck, these arteries can easily be felt pulsating by placing your fingers gently either side of your windpipe. The carotid arteries are essential as they supply blood to the large front part of the brain. This is the brain tissue where thinking, speech, personality and sensory (our ability to feel) and motor (our ability to move) functions reside.
Another smaller set of arteries, the vertebral arteries, are located along the back of the neck adjacent to the spine, and supply blood to the back of the brain.
What is carotid artery disease?
Carotid artery disease is defined by the narrowing or blockage of this artery due to plaque build-up. The process that blocks these arteries (atherosclerosis) is basically the same as that which causes both coronary artery disease and that causes peripheral artery disease (PAD). The slow build-up of plaque (which is a deposit of cholesterol, calcium, and other cells in the artery wall) is caused by high blood pressure, diabetes, tobacco use, high blood cholesterol, and other modifiable risk factors.
Over time, this narrowing may eventually become so severe that a blockage decreases blood flow to the brain and may tragically cause a stroke. A stroke can also occur if a piece of plaque or a blood clot breaks off from the wall of the carotid artery and travels to the smaller arteries of the brain.
The brain survives on a continuous supply of oxygen and glucose carried to it by blood. Cells deprived of fresh blood for more than a few minutes will be damaged, a condition known as “ischemia,” or the brain cells may die, a condition known as “infarction”. When blood flow to the brain is blocked, the result is sometimes called “an ischemic event.” This could be a stroke, which is permanent loss of brain function, or a “transient ischemic attack” (or TIA), which implies a temporary alteration of brain function. Brain damage can be permanent if this lack of blood flow lasts for more than 3 to 6 hours.
Stroke can also occur from other causes than carotid artery disease, for example from heart disease (heart valve problems, heart failure, or artrial fibrillation) or if bleeding occurs in brain tissue. Nevertheless, carotid artery disease is one of the most common causes of stroke. According to the National Stroke Council, more than half of the strokes in the United States occur because of carotid artery disease.