Complications
Atherosclerosis
Atherosclerosis is a common disorder of the arteries. Fat, cholesterol, and other substances collect in the walls of arteries. Larger accumulations are called atheromas or plaque and can damage artery walls and block blood flow. Severely restricted blood flow in the heart muscle leads to symptoms such as chest pain.
As many as half of these deaths were probably due to unhealthy cholesterol and lipid levels. Strong evidence points to LDL as the villain and HDL as a hero in the process. The role of other lipids, notably triglycerides, is not entirely clear.
Unhealthy cholesterol, particularly low-density lipoprotein (LDL), forms a fatty substance called plaque, which builds up on the arterial walls. Smaller plaques remain soft, but older, larger plaques tend to develop fibrous caps with calcium deposits.
Click the icon to see an image of the developmental process of atherosclerosis.
The long-term result is atherosclerosis, commonly called hardening of the arteries. The heart is endangered in two ways by this process:
- Eventually these calcified and inelastic arteries become narrower (a condition known as stenosis). As this process continues, blood flow slows and prevents sufficient oxygen-rich blood from reaching the heart. This condition leads to angina (chest pain) and, in severe cases, to heart attack.
Click the icon to see an image of a heart attack.
- Smaller unstable plaques may rupture, triggering the formation blood clots on their surface. The blood clots block the arteries and are important causes of heart attack.
This process is accelerated and enhanced by other risk factors, including high blood pressure, smoking, obesity, diabetes, and a sedentary lifestyle. When more than one of these risk factors is present, the risk is compounded.
The effects of cholesterol on the heart may involve more than just the arteries. There is some evidence that unhealthy levels may affect the heart muscles and increase the risk for heart failure. High cholesterol levels may even reduce the protection that aspirin provides for people with heart disease.
Lipoprotein(a). Studies are finding an elevated risk for angina and first heart attacks in people with elevated levels of lipoprotein(a), also known as or lp(a). This lipoprotein falls somewhere between HDL and LDL in density and may have some properties that increase the risk for blood clots. Some experts suggest, however, that high levels of lp(a) may merely be markers of late-stage atherosclerosis, not a cause. Because concentrations of lipoprotein(a) are usually inherited, they do not respond to dietary or lifestyle changes. At this time, few experts recommend drug treatments to reduce lp(a) levels. Older women, but not men, appear to be at greater risk for high lp(a) levels and their consequences.
Coronary Artery Disease and High Cholesterol
Coronary artery disease, commonly known as heart disease, is the leading cause of death in the U.S. and was responsible for nearly 500,000 deaths in 2003.
