Every organ and tissue in the body needs a supply of fresh, oxygen-rich blood. That blood is delivered to all parts of the body through blood vessels called arteries. A healthy artery is like a clean pipe: It has a smooth lining and is free of blockages that interfere with blood flow.
Atherosclerosis is the buildup of cholesterol-filled deposits called plaque on the inner walls of arteries. Plaque narrows the vessels and slows down blood flow. Atherosclerosis can occur in any artery in the body, from those nourishing the heart (coronary arteries) to those supplying the brain, intestines, kidneys, and legs.
Atherosclerosis begins as microscopic damage to the inner lining of an artery wall. Many forces can cause this damage, including high blood pressure, cigarette smoke, diabetes, high cholesterol, conditions that cause blood to clot more easily, drugs such as cocaine and androgens, and possibly infections of the inner linings of the arteries.
The first signs of damage are fatty streaks called plaque in the artery wall. These fatty streaks begin early in life and even occur in young adults.
Whatever causes the initial damage, the result is that platelets from the bloodstream gather at the site, soon to be joined by a gruel-like mixture of cholesterol and other fats, calcium deposits, and cell debris.
Cells from the wall of the artery gradually surround the mixture. The artery wall becomes inflamed; white blood cells become activated, race to the injured area, and try unsuccessfully to heal the damage.
Over time, a fibrous cap forms over the fatty deposit. Even under the cap, the deposit can grow, progressively blocking blood flow and ultimately causing chest pain (angina). If the fibrous cap ruptures, a blood clot can form. Such blood clots are the cause of heart attacks and strokes.
Atherosclerosis in coronary arteries leads to chest pain with physical activity or stress (angina). Blockages in the arteries that feed blood to the brain can cause a stroke. Blockages in the arteries that supply the legs result in a painful condition called intermittent claudication.
The first step in fighting atherosclerosis is to keep it from getting worse. You can do this with lifestyle changes such as exercising every day; eating a heart-healthy diet; not smoking; and controlling high blood pressure, high cholesterol, and high blood sugar.
Taking a low-dose aspirin every day is also important. By making blood less likely to clot, aspirin reduces the chances of having a heart attack among men and women with coronary artery disease or those with significant risk factors for it.
Taking a cholesterol-lowering statin can keep atherosclerosis from getting worse, and can also pull cholesterol out of artery-clogging plaque. Statins can also help stabilize atherosclerotic plaques and keep them from breaking open—the event that triggers most heart attacks and strokes.
When lifestyle changes and medications aren't enough to prevent atherosclerosis from causing problematic symptoms—or if you are in serious danger of having a heart attack—you may need angioplasty to open a blocked artery, or coronary artery bypass surgery to carry blood around the obstruction.