Arteriosclerosis, << ahr `tihr` ee oh skluh ROH sihs, >> is a disease of the arteries. It is often called “hardening of the arteries” because it involves hardening, thickening, and loss of elasticity in the artery walls.
There are several forms of arteriosclerosis. Two types are Monckeberg’s arteriosclerosis, in which the middle layer of the arteries becomes stiffened by calcium deposits, and arteriolar sclerosis, which affects the body’s smaller arteries. But by far the most widespread form of arteriosclerosis is the type called atherosclerosis. Atherosclerosis affects medium and large arteries, especially those that carry blood to the heart, brain, kidneys, and legs. The effects of the disease appear mainly in middle-aged or older people, but they may also strike young people. Atherosclerosis ranks as a major health problem in the United States and other developed countries. The remainder of this article discusses atherosclerosis.
Causes.
Atherosclerosis begins when certain fatty substances in the bloodstream—particularly cholesterol—form deposits on the inner lining of the arteries. Over a period of years, these deposits, called fatty streaks, enlarge and thicken to form plaques. The plaques cause inflammation of the smooth lining of the arteries, causing cells to die and scars to form. The build-up of dead cells, calcium, and scar tissue in the plaques makes the arteries hard and narrow, decreasing the flow of blood. Over time, the plaque deposit may be covered with a fibrous lining. A tear or rupture of this lining may cause a thrombus (blood clot) to form on the arterial wall. A thrombus can block an artery suddenly.
Certain risk factors are associated with the development of atherosclerosis. Three major risk factors are hypertension (high blood pressure), cigarette smoking, and high blood levels of cholesterol. Others include obesity, physical inactivity, and diabetes mellitus.
Effects
of atherosclerosis result from the decreased flow of blood through the diseased arteries. Tissues nourished by these arteries do not receive enough oxygen. A decrease in the blood supply to the brain can cause dizziness, numbness, slurred speech, and other symptoms. In the heart, decreased blood supply can produce severe chest pain called angina pectoris. The complete blockage of an artery supplying the heart or the brain results in a heart attack or a stroke, respectively. A reduced flow of blood to the kidneys may cause hypertension or kidney damage. In the legs, it may cause pain while walking, skin sores, or gangrene (death of tissue).
Prevention and treatment.
Most physicians believe that many cases of atherosclerosis can be prevented by reducing exposure to risk factors. Therefore, doctors advise people to avoid cigarette smoking, to reduce if overweight, and to exercise regularly. Detection and control of hypertension and diabetes mellitus are especially important. Many physicians also recommend a diet low in cholesterol and saturated fats.
Treatment of atherosclerosis, like prevention, centers on reducing risk factors. Some patients also get drugs that lower the blood levels of cholesterol. If a major artery becomes obstructed, surgery may be needed. In severe cases, diseased arteries may be replaced or by-passed by grafts of natural or artificial vessels. Another technique, called angioplasty, involves threading a balloon-tipped catheter (slender tube) into the blocked artery. The balloon is then inflated, flattening the blockage against the artery wall.
