Hardening of the arteries, also called atherosclerosis, is a common disorder. It occurs when fat, cholesterol, and other substances build up in the walls of arteries and form hard structures called plaques.
Over time, these plaques can block the arteries and cause symptoms and problems throughout the body.
Causes, incidence, and risk factors
Over the course of years and decades, plaque buildup narrows your arteries and makes them stiffer. These changes make it harder for blood to flow through them.
Clots may form in these narrowed arteries and block blood flow. Pieces of plaque can also break off and move to smaller blood vessels, blocking them.
Either way, the blockage starves tissues of blood and oxygen, which can result in damage or tissue death (necrosis).This is a common cause of heart attack and stroke. If a clot moves into an artery in the lungs, it can cause a pulmonary embolism.
In some cases, the plaque is part of a process that causes a weakening of the wall of an artery. This can lead to an aneurysm. Aneurysms can break open (rupture), and cause bleeding that can be life threatening.
Hardening of the arteries is a process that often occurs with aging. However, high blood cholesterol levels can make this process happen at a younger age.
For most people, high cholesterol levels are the result of an unhealthy lifestyle — most commonly, eating a diet that is high in fat. Other lifestyle factors are heavy alcohol use, lack of exercise, and being overweight.
Other risk factors for hardening of the arteries are:
- Family history of hardening of the arteries
- High blood pressure
Signs and Symptoms
Atherosclerosis typically begins in early adolescence, and is found in major arteries, yet is asymptomatic and not detected by most diagnostic methods during life. Atheroma in arm, or more often in leg arteries, which produces decreased blood flow is called peripheral artery occlusive disease (PAOD).
According to United States data for the year 2004, for about 66% 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 onset of the symptom).
Most artery flow disrupting events occur at locations with less than 50% lumen narrowing (~20% stenosis is average). The illustration above, like most illustrations of arterial disease, overemphasizes lumen narrowing, as opposed to compensatory external diameter enlargement (at least within smaller arteries, e.g., heart arteries) typical of the atherosclerosis process as it progresses (see Glagov or the ASTEROID trial). The relative geometry error within the illustration is common to many older illustrations, an error slowly being more commonly recognized within the last decade.
Cardiac stress testing, traditionally the most commonly performed non-invasive testing method for blood flow limitations, in general, detects only lumen narrowing of ~75% or greater, although some physicians claim that nuclear stress methods can detect as little as 50%.