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 with walking)
Atherosclerosis
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 and lodge in arteries downstream, blocking them off. In these cases, the tissue supplied by the artery receives no oxygen and quickly dies. 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 build-up 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 chance of getting a disease or condition.
• Risk factors you cannot control:
o Father or brother who developed complications of atherosclerosis before age 55 or mother or sister who developed complications of atherosclerosis before age 65
o Age: 45 and older for men; 55 and older for women
o Sex: men have a greater risk of heart attack than women
• Risk factors you can control:
o High cholesterol, especially LDL ("bad") cholesterol and low HDL (“good”) cholesterol
o High blood pressure
o Cigarette smoking
o Diabetes, type 1 and type 2
o Overweight and obesity
o Lack of physical activity
o Metabolic syndrome, which is a combination of three out of the following five findings: low HDL-cholesterol, high triglycerides, elevated blood sugar, elevated blood pressure, and increased waist circumference (greater than 40 inches in men and 35 inches in women).
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 for risk factors that predispose them to atherosclerosis.
If you have symptoms, your doctor will ask you questions to determine what arteries might be affected. The doctor will also need to know your full medical history, and perform a physical exam. Tests will depend on which arteries are likely involved based on your symptoms, physical exam, and/or risk factors. Many of these tests detect problems with the tissue receiving insufficient blood supply. Two common tests that directly evaluate the atherosclerotic arteries are:
• Angiography–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:
Medications
These include:
• Drugs to interfere with the formation of blood clots, such as aspirin or clopidegril (Plavix)
• Drugs to control blood pressure, if elevated
• Drugs to lower cholesterol, if elevated
• Drugs that improve the flow of blood through narrowed arteries, such as cilostazol (Pletal) or pentoxifylline (Trental)
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. This procedure is infrequently done these days.
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.
• If your doctor recommends it, take medication to reduce your risk factors (for example, for high blood pressure or high cholesterol).
• Talk to your doctor about screening tests for atherosclerotic disease of the heart (coronary artery disease) if you have risk factors.
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