How atherosclerosis develops

Atherosclerosis may start when the innermost layer of the artery, known as the endothelium, becomes damaged, allowing cholesterol to attach. Damage to the arterial wall can be caused by elevated levels of cholesterol and triglycerides in the blood; high blood pressure, and tobacco smoke. Atherosclerosis begins early in adulthood, but it may be decades before it becomes obvious.

Once the endothelium is damaged, calcium, fats, cholesterol, fibrin, platelets, cellular debris and other substances can catch on the damaged spot and deposit on the artery wall, stimulating plaque development. In some instances, atherosclerosis may weaken the blood vessel wall, causing the vessel to become wider, rather than narrower.

Although the dangers of narrowed blood vessels are well known, widening also can be a serious problem. If this occurs, the inside diameter of the blood vessel may change only slightly, despite the presence of plaque. This explains why some people can have a fairly normal stress test or angiogram, but still have coronary artery disease and even heart attacks.

Learn more about plaque

In addition to coronary artery disease, atherosclerosis may cause the following.

Stroke, aneurysm, claudication

If atherosclerosis affects blood vessels feeding the brain, the blood supply to a portion of the brain may be restricted or cut off, causing a stroke.

Stroke is a medical emergency.

Call 911. See more information about stroke.

Atherosclerosis can lead to an aneurysm, a fluid- and blood-filled sac in the wall of an artery or vein. If an aneurysm ruptures, the result is internal bleeding and lack of adequate blood supply where it is needed.

When atherosclerosis develops in the blood vessels going to the legs, it can result in leg pain during exercise, also called claudication.