Sizes and ShapesPlaque 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.