Atherosclerosis Health Article

Definition

Atherosclerosis is the build up of plaque on the inside of blood vessels. Atherosclerosis is often called arteriosclerosis, which is a general term for hardening of the arteries.

Description

Atherosclerosis, a progressive condition responsible for most heart disease, is a type of hardening of the arteries. It can be caused by normal aging processes, by high blood pressure, and by some diseases, such as diabetes. Atherosclerosis can begin in the late teens, but it usually takes decades for the signs and symptoms of the disease to be apparent. Some people experience rapidly progressing atherosclerosis in their 30s or later.

An artery is made up of several layers: an inner lining called the endothelium, an elastic membrane that allows the artery to expand and contract, a layer of smooth muscle, and a layer of connective tissue. Atherosclerosis affects the inner lining of an artery. It is characterized by plaque deposits that block the flow of blood. Plaque is made of fatty substances, cholesterol, waste products from the cells, calcium, iron, and fibrin, a material that helps clot blood.

As plaque builds up in and around the cells of the artery walls, they accumulate calcium. The innermost layer thickens, the artery's diameter is reduced, and blood flow and oxygen delivery are decreased. Plaque can rupture or crack open, causing the sudden formation of a blood clot, called a thrombosis. As a result of thrombosis and/or the buildup of plaque, atherosclerosis can cause a heart attack if it completely blocks the blood flow in the coronary arteries. It can cause a stroke if it completely blocks the carotid arteries of the brain. Atherosclerosis can also occur in the arteries of the neck, kidneys, thighs, and arms, and may lead to kidney failure, gangrene, and even death.

Causes & symptoms

It is thought that atherosclerosis is caused by the body's response to damage to the artery wall from cholesterol, high blood pressure, and cigarette smoking. A person who has all three of these risk factors is eight times more likely to develop atherosclerosis than is a person who has none. Physical inactivity, damage by oxidants, diabetes, and obesity are also risk factors for atherosclerosis. High levels of the amino acid homocysteine and abnormal levels of fats called lipoproteins also raise the risk. Other risk factors include:

• High triglycerides. Most fat in food and in the body takes the form of triglycerides. Blood triglyceride levels above 400 mg/dL have been linked to atherosclerosis.
• Physical inactivity. Lack of exercise increases the risk of atherosclerosis.
• Diabetes mellitus. The risk of developing atherosclerosis is seriously increased for diabetics and can be lowered by keeping diabetes under control. Many diabetics die from heart attacks caused by atherosclerosis.
• Obesity. Excess weight increases the strain on the heart and increases the risk of developing atherosclerosis, even if no other risk factors are present.
• Heredity. People whose parents have coronary artery disease, atherosclerosis, or stroke at an early age are at increased risk.
• Sex. Before age 60, men are more likely to have heart attacks than women.
• Age. Risk is higher in men who are 45 years of age and older and women who are 55 years of age and older.

The symptoms of atherosclerosis differ depending upon the location. They may involve:

• In the coronary (heart) arteries: chest pain, heart attack, and sudden death.
• In the carotid arteries of the brain: sudden dizziness, weakness, loss of speech, and blindness.
• In the femoral arteries of the legs: cramping and fatigue in the calves of the legs when walking.
• In the renal arteries of the kidneys: high blood pressure resistant to treatment.