Atherosclerosis
Definition |
Causes |
Risk Factors |
Symptoms |
Diagnosis |
Treatment |
Prevention |
Organizations
Definition
Atherosclerosis is a form of arteriosclerosis (hardening of the arteries) affecting large and medium-sized arteries. Fatty deposits, called "atheromas" or plaques, damage the lining of arteries causing them to narrow and harden. As plaque deposits gradually enlarge, they interfere with blood flow. This often leads to pain or decreased function in those tissues supplied by the affected arteries. Depending on which arteries are involved, atherosclerosis can cause a number of serious health problems. These include:
- Coronary heart disease
- Stroke
- Peripheral vascular disease (characterized by leg pain and difficulty walking)
Due to the repeated damage to the inner arterial wall, blood clots often form. These clots, called thrombi, lead to a further decrease in blood flow. In some cases, a thrombus may become so large that it completely closes off the artery. Or, it may break into clumps, called emboli, that travel through the bloodstream. In these cases, the tissues supplied by the artery receive no oxygen and quickly die. When this occurs in the heart, it is called a heart attack. In the brain, it is called a stroke.
Long-term atherosclerosis can also cause arteries to weaken. In response to pressure, they may bulge, leading to the formation of an aneurysm. If untreated, an aneurysm can rupture and bleed.
Causes
Atherosclerotic plaques are caused by a buildup of fatty deposits in the lining of the artery. Plaque consists mainly of cholesterol and other fats, calcium, and scar tissue.
Although the process leading to atherosclerosis may begin in childhood, it takes decades before it becomes severe enough to cause serious health problems.
Risk Factors
A risk factor is something that increases your chances of getting a disease or condition.
- Risk factors you cannot control:
- Family members who developed complications of atherosclerosis before age 55
- Age: 45 and older for men; 55 and older for women
- Risk factors you can control:
Symptoms
There are no symptoms in early atherosclerosis. As the arteries become harder and narrower, symptoms may gradually appear. However, if a clot blocks a blood vessel or a large embolus breaks free, symptoms can occur suddenly, sometimes without warning.
Symptoms depend on which arteries are affected. For example:
- Coronary (heart) arteries – may cause symptoms of heart disease, such as chest pain.
- Arteries in the brain – may cause symptoms of a stroke such as weakness or dizziness.
- Arteries in the lower extremities – may cause pain in the legs or feet, and trouble walking.
Diagnosis
Most people are diagnosed with atherosclerosis after they develop symptoms. However, because the disease develops over such a long period of time, people can be screened and treated well before they would have shown symptoms.
The doctor will ask about your symptoms (if any) and medical history, and perform a physical exam. Tests will depend on which arteries are likely involved based on your symptoms and/or risk factors. Many of these tests detect problems with the tissues receiving insufficient blood supply. Two common tests that directly evaluate the atherosclerotic arteries are:
- Angiography (cardiac catheterization) – A tube-like instrument is inserted into an artery through which dye is injected to help determine the degree of blood flow. When done in the heart, this test is called cardiac catheterization.
- Ultrasound – A test that uses sound waves to examine the inside of the body, in this case the size and shape of arteries.
Treatment
An important part of treatment is reducing risk factors. To do so, see the steps in the prevention section below. Beyond that, treatment depends on the area of the body most affected.
Treatment may include:
Medicine
These include:
- Drugs to interfere with the formation of blood clots, such as aspirin
- Drugs that improve the flow of blood through narrowed arteries, such as pentoxifylline (Trental)
- Drugs to control blood pressure, if elevated
- Drugs to lower cholesterol, if elevated
Catheter-based Procedures
These procedures involve a thin tube, called a catheter, that is inserted into an artery. They are most often done for coronary artery disease, but may be used to treat atherosclerosis elsewhere in the body as well. These procedures include:
- Balloon Angioplasty – A balloon-tipped catheter is used to press plaque against the walls of the arteries. This increases the amount of space for the blood to flow.
- Stenting – Usually done after angioplasty; a wire mesh tube is placed in a damaged artery to support the arterial walls and keep them open.
- Atherectomy – Instruments inserted via a catheter are used to cut away and remove plaque so that blood can flow more easily.
Surgery
Surgical options include:
- Endarterectomy – Removal of the lining of an artery obstructed with large plaques. This is often done in carotid arteries of the neck, which bring blood to the brain.
- Arterioplasty – Repair of an aneurysm, usually done with synthetic tissue.
- Bypass – Creation of an alternate route through a separate vessel for blood to flow.
Prevention
There are a number of ways to prevent, as well as reverse, atherosclerosis. They include:
- Eat a healthful diet, one that is low in saturated fat and cholesterol, and rich in whole grains, fruits, and vegetables.
- Exercise regularly.
- Maintain a healthy weight. If you are overweight, lose weight.
- Don't smoke. If you smoke, quit.
- Control diabetes.
- Take medicine, if your doctor recommends it.
- Talk to your doctor about screening tests for atherosclerotic disease of the heart (coronary artery disease) if you have many risk factors but no symptoms yet.
Organizations
American Heart Association
http://www.americanheart.org
SOURCES:
American Heart Association
American College of Radiology
The Merck Manual of Diagnosis and Therapy. Simon and Schuster, 1999.
Last reviewed January 2002 by Medical Review Board
