The illness

Atherosclerosis (ath"er-o-skleh-RO'sis) comes from the Greek words athero (meaning gruel or paste) and sclerosis (hardness). It's the name of the process in which deposits of fatty substances, cholesterol, cellular waste products, calcium and other substances build up in the inner lining of an artery. This buildup is called plaque. It usually affects large and medium-sized arteries.

Plaques can grow large enough to significantly reduce the blood's flow through an artery. But most of the damage occurs when they become fragile and ruptured. Plaques that rupture cause blood clots to form that can block blood flow or break off and travel to another part of the body.

Atherosclerosis can affect the arteries of the brain, heart, kidneys, other vital organs, and the arms and legs. When atherosclerosis develops in the arteries that supply the brain (carotid arteries), a stroke may occur; when it develops in the arteries that supply the heart (coronary arteries), a heart attack may occur and if blood supply to the arms or legs is reduced, it can cause difficulties in walking and eventually gangrene.

Atherosclerosis is a slow, complex disease that typically starts in childhood and often progresses as people grow older. In some people it progresses rapidly, even in their third decade. In others it doesn’t become threatening until they’re in their fifties or sixties.

Atherosclerosis usually has no symptoms until the narrowed coronary arteries severely restrict blood flow to the heart. At this point, the patient may feel chest pain because not enough blood is reaching the heart. These pains may come with exertion, or can occur when the patient is at rest.

The cause

How exactly atherosclerosis begins is not known, but some theories have been proposed.

Many scientists think atherosclerotic process begins when some white blood cells, called monocytes, migrate from the bloodstream into the wall of the artery and are transformed into cells that accumulate fatty materials. Over time, these fat-laden monocytes accumulate, leading to a patchy thickening in the inner lining of the artery, the endothelium. Each area of thickening (called an atherosclerotic plaque or atheroma) is filled with a soft cheese-like substance consisting of various fatty materials, principally cholesterol, smooth muscle cells, and connective tissue cells.

Usually the plaques form where the arteries branch off. The blood vessels affected with atherosclerosis lose their elasticity, and as the atheromas grow, the arteries narrow. With time, the atheromas collect calcium deposits, may become brittle, and may rupture. Blood may then enter a ruptured plaque, making it larger, so that it narrows the artery even more. A ruptured atheroma also may spill its fatty contents and trigger the formation of a blood clot (thrombus). The clot may further narrow or even occlude the artery, or it may detach and float downstream where it causes an occlusion (embolism).

The risk

It is known that several risk factors may increase the possibility to develop atherosclerosis. Some of them are not controllable such as having a family history of premature cardiovascular disease. Others that can be easily limited by anyone of us include:

- High blood cholesterol (especially LDL or "bad" cholesterol over 100 mg/dL)
- Cigarette smoking and exposure to tobacco smoke
- High blood pressure
- Diabetes mellitus
- Obesity
- Physical inactivity

The treatment

In general, atherosclerosis is faced by making changes in diet and lifestyle. Increasing exercise and, when prescribed by a physician, a treatment with medications can be useful to reduce the fats and cholesterol in the blood. More radical treatments include angioplasty (a catheter with a balloon on the end used to flatten plaque and open up the artery) and stenting (a small, metal mesh cylinder placed inside the artery after angioplasty to keep the artery open). In some cases, open heart surgery is required.