Atherosclerosis

Atherosclerosis – Definition

Atherosclerosis is hardening of a blood vessel from a buildup of plaque. Plaque is made of fatty deposits, cholesterol, and calcium. It builds on the inside lining of arteries. This causes the artery to narrow and harden. It affects large and medium-sized arteries.

As plaque builds up it can slow and even stop blood flow. This means the tissue supplied by the affected artery is cut off from its blood supply. This often leads to pain or decreased function. This condition can cause a number of serious health problems. Depending on the location of the blockage, it can cause:

• Coronary heart disease — loss of blood to areas of the heart
• Stroke — loss of blood to areas of the brain
• Peripheral vascular disease — characterized by leg pain with walking

In addition, a hardened artery is more likely to be damaged. Repeated damage to the inner wall of an artery causes blood clots often form. The clots are called thrombi. They can lead to a further decrease in blood flow. In some cases, a thrombus may become so large that it completely closes off the artery. It could also break into clumps, called emboli. These clumps travel through the bloodstream and lodge in smaller arteries, blocking them off. In these cases, the tissue supplied by the artery receives no oxygen. It 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. This bulge is called an aneurysm. If untreated, they can rupture and bleed.

Atherosclerosis – Causes

Atherosclerosis is caused by plaque. Plaque is created by high levels of cholesterol and fat in the blood. Scar tissue and calcium from vessel injury can also add to the plaque buildup.

The process leading to this may begin in childhood. It takes decades before it causes serious health problems.

Atherosclerosis – Risk Factors

There are two types of factors that increase your chance of atherosclerosis:

• Risk factors you cannot control:
  • Father or brother who developed complications of atherosclerosis before age 55 or mother or sister who developed complications of atherosclerosis before age 65
  • Age: 45 years and older for men; 55 years and older for women
  • Sex: men have a greater risk of heart attack than women
• Risk factors you can control:
  • High cholesterol — especially low-density lipoprotein (LDL) (“bad”) cholesterol and low high-density lipoprotein (HDL) (“good”) cholesterol
  • High blood pressure
  • Cigarette smoking
  • Diabetes, type 1 and type 2
  • Overweight and obesity
  • Lack of physical activity
  • Metabolic syndrome — a combination of three out of the following five findings:
    • Low HDL-cholesterol — also called good cholesterol
    • High triglycerides
    • Elevated blood sugar
    • Elevated blood pressure
    • Increased waist circumference (greater than 40 inches in men and 35 inches in women)

Atherosclerosis – Symptoms

There are none in early atherosclerosis. As the arteries become harder and narrower, symptoms may begin to appear. If a clot blocks a blood vessel or a large embolus breaks free, symptoms can occur suddenly.

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

Atherosclerosis – Diagnosis

Most people are diagnosed after they develop symptoms. However, people can be screened and treated for risk factors.

If you have symptoms, your doctor will ask you questions. These will help to determine what arteries might be affected. The doctor will also need to know your full medical history. A physical exam will be done. Tests will depend on which arteries may be involved. Test will be decided based on your symptoms, physical exam, and/or risk factors. Many of these tests detect problems with the tissue that is not getting enough blood. Two common tests that directly evaluate the atherosclerotic arteries are:

• Angiography — a tube-like instrument is inserted into an artery. Dye is injected into the vessel 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 test examines the size and shape of arteries.

Atherosclerosis – 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:

Medicines

These include:

• Drugs to interfere with the formation of blood clots, such as aspirin or clopidogrel (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. It is inserted into an artery. They are most often done for arteries in the heart. They 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. It will support the arterial walls and keep them open.
• Atherectomy — instruments are inserted via a catheter. They are used to cut away and remove plaque so that blood can flow more easily. This procedure is not done often 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. These arteries bring blood to the brain.
• Arterioplasty — repair of an aneurysm. It is usually done with synthetic tissue.
• Bypass — creation of an alternate route for blood flow. The procedure uses a separate vessel for blood to flow.

Atherosclerosis – Prevention

There are a number of ways to prevent, as well as reverse, atherosclerosis. They include:

• Eat a healthful diet. It should be low in saturated fat and cholesterol. It should also be 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. This may include medicine 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.