There are a number of links between statins and heart disease. The main connection is that statins are used to treat high blood lipid levels, a condition that is known to be a risk factor in the development of heart disease. Deciding whether or not to start a statin to treat high cholesterol levels depends on whether a patient already has underlying heart disease. Additionally, patients who suffer from heart attacks are usually prescribed statins because the medication improves their recovery and decreases their risk for repeat heart attacks.
The most important connection between statins and heart disease is that statins are a class of medications used to treat a condition called dyslipidemia, which is a known risk factor for the development of heart disease. When patients have elevated blood cholesterol or blood triglyceride levels, they are said to have dyslipidemia. This condition can develop as a result of having a genetic predisposition towards the disease, or from having a diet rich in saturated fats. Having high lipids in the blood can promote the formation of atherosclerosis, which is the narrowing of the blood vessels as a result of plaque development. Narrow blood vessels cannot carry as much blood as normal ones can, and this can lead to the heart receiving a poor blood supply, causing a variety of heart diseases.
Statins and heart disease are also linked because whether or not a patient is started on a statin medication depends on whether he has underlying heart disease. Healthy patients without any medical problems would only be started on statin therapy if their low-density lipoprotein (LDL) level, a measurement commonly referred to as the "bad cholesterol" level, reaches a level greater than 190 milligrams per deciliter (mg/dl). In contrast, if patients have underlying coronary artery disease, in which they have narrowing of the vessels supplying blood to the muscle of the heart, they are started on a statin with a much lower LDL level. Many times they would be started on a statin with an LDL level greater than 100 mg/dl.
Another connection between statins and heart disease is that medications in the statin class are prophylactically given to many patients after they have had a heart attack, regardless of the concentration of cholesterol and lipids they have in their blood. A number of studies have shown that this medication is beneficial in helping patients recover from their heart attacks, and in preventing future similar events from occurring. It is thought that the statins not only lower the blood lipid levels but also have some anti-inflammatory effects and some ability to help prevent the blood from clotting.