Atherosclerosis is a chronic, progressive disease in which plaques (consisting of deposits of cholesterol and other lipids, calcium, and large inflammatory cells called macrophages) build up in the walls of the arteries.
These plaques can cause several problems. First, plaques can protrude into the artery, eventually causing a partial or complete obstruction to blood flow. Second, plaques can suddenly rupture, causing a thrombus (blood clot) to form, leading to sudden occlusion of the artery. (This condition is called arterial thrombosis.) Third, plaques can weaken the wall of the artery causing a ballooning out of the artery to form what is called an aneurysm. The rupturing of an aneurysm often produces severe internal bleeding.
What causes atherosclerosis?
The fundamental underlying cause of atherosclerosis has not been fully established. However, many factors that contribute to atherosclerosis have been identified, including:
- Genetic predisposition - the propensity for atherosclerosis clearly runs in families. Anybody whose close relatives (parents, sibs, uncles and aunts) have had atherosclerosis ought to take every opportunity to reduce their own risk factors.
- Cholesterol abnormalities - high blood levels of LDL cholesterol, and low levels of HDL cholesterol, are associated with atherosclerosis.
- Sedentary lifestyle
- Obesity, especially abdominal obesity
In Western cultures, arteries commonly show early changes of atherosclerosis even in childhood and adolescence. This is a disease that develops over a period of decades before it ever begins to produce symptoms.
Which arteries are affected?
Atherosclerosis commonly affects the coronary arteries, leading to angina and myocardial infarction (heart attack); the cerebrovascular circulation (brain arteries), leading to stroke; the renal arteries, leading to kidney disease; the aorta, leading to aortic aneurysm; and the blood vessels of the arms and (especially) the legs, leading to claudication, ulceration, skin changes, and slow-healing.
In the United States, atherosclerosis causes more death and disability than any other disease.
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Strong, JP, Malcom, GT, McMahan, CA, et al. Prevalence and extent of atherosclerosis in adolescents and young adults. Implications for prevention from the pathobiological determinants of atherosclerosis in youth study. JAMA 1999; 281:727.