Atherosclerosis

Atherosclerosis is a disease affecting arterial blood vessel. It is commonly referred to as a "hardening" or "furring" of the arteries. It is caused by the formation of multiple plaques within the arteries. Pathologically, the atheromatous plaque is divided into three distinct components: more...

The atheroma ("lump of porridge", from Athera, porridge in Greek,) is the nodular accumulation of a soft, flaky, yellowish material at the center of large plaques, composed of macrophages nearest the lumen of the artery, sometimes with underlying areas of cholesterol crystals and possibly also calcification at the base of older/more advanced lesions.

Arteriosclerosis ("hardening of the artery") results from a deposition of tough, rigid collagen inside the vessel wall and around the atheroma. This increases the stiffness, decreases the elasticity of the artery wall. Arteriolosclerosis (hardening of small arteries, the arterioles) is the result of collagen deposition, but also muscle wall thickening and deposition of hyaline cartilage.

Calcification, sometimes even ossification (formation of complete bone tissue) occurs in the thickest parts of sclerosed vessel wall.

Some sources draw a distinction between "Arteriosclerosis", "Atherosclerosis," and "Arteriolosclerosis". In these contexts, "Atherosclerosis" is used when referring to larger arteries, and "Arteriolosclerosis" is used when referring to arterioles, with "Arteriosclerosis" used as a parent of both terms. Atherosclerosis causes two main problems. First, the atheromatous plaques causes stenosis (narrowing) of the artery and, therefore, an insufficient blood supply to the organ it feeds. This complication is chronic, slowly progressing. A common scenario is claudication from insufficient blood supply to the legs. Second, the soft plaque may suddenly rupture (see vulnerable plaque), causing the formation of a blood clot (thrombus) that will rapidly stop blood flow, leading to death of the tissues fed by the artery. This catastrophic event is called an infarction. The most common scenario is a thrombosis of a coronary artery causing myocardial infarction (a heart attack).

Symptoms

Atherosclerosis typically begins in later childhood, is usually found in most major arteries, yet is asymptomatic and not detected by most diagnostic methods during life. It most commonly becomes seriously symptomatic when interfering with the coronary circulation supplying the heart or cerebral circulation supplying the brain, and is considered the most important underlying cause of strokes, heart attacks, various heart diseases including congestive heart failure and most cardiovascular diseases in general. Atheroma in arm or more often leg arteries and producing decreased blood flow is called Peripheral artery occlusive disease (PAOD).

According to United States data for the year 2004, for about 65% of men and 47% of women, the first symptom of atherosclerotic cardiovascular disease is heart attack or sudden cardiac death (death within one hour of symptom onset).

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