Cholesterol is a major ingredient in the plaque that builds up in the coronary arteries (the blood vessels that supply blood to the heart) and causes
heart disease.
Excess cholesterol is deposited on the artery walls as it travels through the bloodstream. Then, special cells in the artery wall gobble up this excess cholesterol, creating a "bump" in the artery wall. This cholesterol-rich "bump" then is covered by a scar that produces a hard coat or shell over the cholesterol and cell mixture. It is this collection of cholesterol covered by a scar that is called plaque. The buildup of plaque is known as
atherosclerosis.
The plaque buildup narrows the space in the coronary arteries through which blood can flow, decreasing the supply of oxygen and nutrients to the heart.
If not enough oxygen-carrying blood can pass through the narrowed arteries to reach the heart muscle, the heart may respond with a pain called
angina. The pain is often felt during exercise, when the heart needs more oxygen. It is typically felt in the chest or sometimes in other places, like the left arm and shoulder. This same inadequate blood supply, however, may cause no symptoms.
This plaque buildup does not occur over days, weeks, or months. Plaque buildup, in most cases, occurs over many years.
Plaque comes in various sizes and shapes. Throughout the coronary arteries, many small buildups of plaque build themselves into the walls of the arteries, blocking less than half of the artery opening. These small buildups are often invisible on many of the tests doctors use to identify coronary
heart disease.
It used to be thought that the most dangerous buildups of plaque -- and the ones most likely to cause total blockage of coronary arteries -- were the largest ones. The largest buildups of plaque are, in fact, the ones most likely to cause
angina. But small buildups of plaque that are full of
cholesterol and covered by a scar are now thought to be highly unstable and more likely to rupture or burst, releasing their cholesterol contents into the bloodstream. When this happens, it triggers blood clotting inside the artery. If the blood clot totally blocks the artery, it stops blood flow and a
heart attack occurs. The muscle on the far side of the blood clot does not get enough oxygen and begins to die. The damage can be permanent.
Lowering cholesterol levels can slow, stop, or even reverse the buildup of plaque. This can reduce your risk of a heart attack by lowering the cholesterol content in unstable plaque, making it more stable and less prone to rupture. This is why lowering your
LDL cholesterol is such an important part of reducing your risk of a heart attack. Even in people who have had one heart attack, the chances of having future attacks can be substantially reduced by lowering cholesterol.
