Atherosclerosis comes from two Greek words meaning paste and hardness. It occurs when fatty substances accumulate in the inner lining of an artery. This build up is called plaque. Two things that can happen where plaque occurs are:
* bleeding into the plaque, and
* formation of a blood clot on the outside of the plaque.

If either of these occurs and blocks the artery, a heart attack, gangrene, or stroke may occur.

Plaques can affect both large and medium sized arteries. How plaques begin or what causes them isn't known. Over time, however, the lining of important blood vessels can become thick and hard. If an artery becomes blocked and stops the flow of blood to the heart muscle, a heart attack happens. If the artery brings blood to a leg or arm and it becomes blocked, this can cause numbness, pain and gangrene to the extremity. If the artery is in the brain and it becomes blocked, this causes a stroke. Sometimes small arteries that are hard also break and release blood. This almost always happens in the brain and when it does, it also causes a stroke.

Because plaques contain cholesterol, persons with high levels of cholesterol in their blood have a high chance of forming plaque in their vessels. Other things that may cause this problem are:
* high levels of fat in the blood,
* smoking,
* high blood pressure, and
* diabetes.

There is now a great deal of research on atherosclerosis. Some is aimed at learning how cholesterol and fats are absorbed into cells. Other research has shown that lowering high levels of cholesterol reduces deaths from heart attack. Yet another advance has been in the development of new cholesterol lowering drugs.

To learn more, contact your local Heart Association office or call (800) 242-8721.

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