What is Carotid Artery Disease & Stroke?

Your arteries carry oxygen-rich blood away from the heart to the head and body. There are two carotid arteries (one on each side of the neck) that supply blood to the brain, these arteries are called the common carotid. Each common carotid splits into two branches -- the internal branch, which brings oxygen-rich blood to the brain, and the external branch, which brings blood to the face.

Over time, plaque (fat & cholesterol deposits) can build-up and cause narrowing and sometimes a complete blockage of the artery.  Blockage of the internal carotid artery can reduce blood supply to the brain.
 
Over time, the plaque itself may block the artery enough to cause a stroke.  A stroke is similar to a heart attack. A stroke occurs when brain cells (neurons) are deprived of the oxygen and glucose carried to them by blood. Oxygen and glucose are essential for neurons to function and survive. If the lack of blood flow lasts for more than 3 to 6 hours, the damage is usually permanent.

In addition, the plaque often causes the blood to flow abnormally, which leads to a blood clot. A clot can stay at the site of narrowing and prevent blood flow to all of the smaller arteries it supplies. This type of clot, which doesn't travel, is called a thrombus. In other cases, the clot can travel and wedge into a smaller vessel. A clot that travels is called an embolism.

If you develop a thrombus in the internal carotid artery or an embolism in a smaller blood vessel, you may experience symptoms such as blurred vision, slurred speech, or weakness (all signs of stroke).

By restoring adequate blood flow to the internal carotid artery, strokes can be prevented. This may be accomplished either by a surgery called endoarterectomy or a procedure known as angioplasty with stent placement. Traditionally used for the heart, this latter procedure is now being used on blood vessels to the brain as well. Stent placement is an alternative to surgery that enlarges the blockage in the artery.