The statins (including Lipitor, Zocor, Pravachol, Lescol and others) work to reduce the blood levels of cholesterol, perhaps more importantly the blood levels of LDL cholesterol (the so-called "bad" cholesterol). We have assumed that by lowering the blood levels of LDL cholesterol we would also reduce the risk of heart disease and of heart attack. We now know that it is a bit more complicated; simply lowering cholesterol may not be the whole answer to how these drugs work.
The buildup of fatty deposits inside blood vessels (called plaque) is a complicated process that involves the amount of LDL cholesterol in the blood and a number of other factors. We know that we can slow down the buildup of plaque in many patients when we use the statins. In some people with small amounts of plaque, we can actually see the plaque get smaller or disappear. The statins can also make the plaque much less likely to cause problems. This is called "plaque stabilization." It turns out that not all plaque is equal. Some deposits are more likely to cause a heart attack than others. The statins appear to turn this unstable kind of plaque into a more stable version. Many experts believe that this is why the statins are so effective in reducing the risk of heart attack. This plaque stabilization doesn't appear to be related to the cholesterol-lowering effects of the statins. Some experts believe that plaque stabilization may be related to the effects of the statins on blood-vessel inflammation.