Cholesterol and Artery Plaque Buildup

Cholesterol plaques are the culprits of heart disease. Plaques begin in artery walls and grow over years. The growth of cholesterol plaques slowly blocks blood flow in the arteries. Worse, a cholesterol plaque can suddenly rupture. The sudden blood clot that results then causes a heart attack or stroke.

Blocked arteries caused by plaque buildup and blood clots are the leading cause of death in the U.S. Reducing cholesterol and other risk factors can help prevent cholesterol plaques from forming. Occasionally, it can even reverse some plaque buildup.

Cholesterol Plaques and Atherosclerosis

Cholesterol plaques form by a process called atherosclerosis. Another name for atherosclerosis is "hardening of the arteries." LDL or "bad cholesterol" is the raw material of cholesterol plaques. Progressive and painless, atherosclerosis grows cholesterol plaques silently and slowly. The eventual result is blocked arteries, which places blood flow at risk.

The cholesterol plaques of atherosclerosis are the usual cause of heart attacks, strokes, and peripheral arterial disease. These conditions together are called cardiovascular disease. Cardiovascular disease is the No. 1 killer in America, causing more than 900,000 deaths each year.

The Life and Times of a Cholesterol Plaque

Cholesterol plaques start developing in the walls of arteries. Long before they can be called plaques, hints of atherosclerosis can be found in the arteries. Even some adolescents have these "fatty streaks" of cholesterol in their artery walls. These streaks are early precursors of cholesterol plaques. They can't be detected by tests. But researchers have found them during autopsies of young victims of accidents and violence.

Atherosclerosis develops over years. It happens through a complicated process of cholesterol plaque formation that involves:

• Damaged endothelium. The smooth, delicate lining of blood vessels is called the endothelium. High cholesterol, smoking, high blood pressure, or diabetes can damage the endothelium, creating a place for cholesterol to enter the artery's wall.
• Cholesterol invasion. "Bad" cholesterol (LDL cholesterol) circulating in the blood crosses the damaged endothelium. LDL cholesterol starts to accumulate in the wall of the artery.
• Plaque formation. White blood cells stream in to digest the LDL cholesterol. Over years, the toxic mess of cholesterol and cells becomes a cholesterol plaque in the wall of the artery.

Cholesterol Plaque Attacks: Cardiovascular Disease

Once established, cholesterol plaques can behave in different ways.

• They can stay within the artery wall. The cholesterol plaque may stop growing, or may grow into the wall, out of the path of blood.
• Plaques can grow in a slow, controlled way into the path of blood flow. Slow-growing cholesterol plaques may or may not ever cause any symptoms -- even with severely blocked arteries.
• The worst-case scenario is that cholesterol plaques can suddenly rupture. This will allow blood to clot inside an artery. In the heart, this causes a heart attack. In the brain, it causes a stroke.

Cholesterol plaques of atherosclerosis cause the three main kinds of cardiovascular disease:

• Coronary artery disease -- Stable cholesterol plaques in the heart's arteries can cause no symptoms or can cause chest pain called angina. Sudden cholesterol plaque rupture and clotting causes blocked arteries. When that happens, heart muscle dies. This is a heart attack, also called myocardial infarction.
• Cerebrovascular disease -- Cholesterol plaque ruptures in one of the brain's arteries. This causes a stroke, leading to permanent brain damage. Blockages can also cause transient ischemic attacks, or TIAs. A TIA has symptoms like those of stroke. But they are temporary and there is no brain damage.
• Peripheral arterial disease -- Blocked arteries in the legs can cause pain on walking and poor wound healing due to poor circulation. Severe disease may lead to amputations.