Atherosclerosis

What is atherosclerosis?

Atherosclerosis is a type of arteriosclerosis caused by a build-up of plaque in the inner lining of an artery. (Arteriosclerosis is a general term for thickening or hardening of the arteries.) Plaque is made up of deposits of fatty substances, cholesterol, cellular waste products, calcium, and fibrin, and can develop in medium or large arteries. The artery wall becomes thickened and loses its elasticity.

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Atherosclerosis is a slow, progressive disease that may start as early as childhood. However, the disease has the potential to progress rapidly.

What causes atherosclerosis?

It is unknown exactly how atherosclerosis begins or what causes it. Some scientists think that certain risk factors may be associated with atherosclerosis, including:

• elevated cholesterol and triglyceride levels
• high blood pressure
• smoking
• diabetes mellitus (type 1 diabetes)
• obesity
• physical inactivity
• high saturated fat diet

How does the disease progress?

There is a gradual build-up of plaque or thickening of the inside of the walls of the artery, causing a decrease in the amount of blood flow, and a decrease in the oxygen supply to the vital body organs and extremities.

A heart attack may occur if the oxygenated blood supply is reduced to the heart. A stroke may occur if the oxygenated blood supply is cut off to the brain. Gangrene may occur if the oxygenated blood supply is reduced to the arms and legs.

What are the symptoms of atherosclerosis?

Signs and symptoms of atherosclerosis may develop gradually, and may be few, as the plaque builds up in the artery. Symptoms may also vary depending on the affected artery. However, when a major artery is blocked, signs and symptoms may be severe, such as those occurring with heart attack, stroke, aneurysm, or blood clot.

The symptoms of atherosclerosis may resemble other cardiac conditions. Consult your physician for a diagnosis.

How is atherosclerosis diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for atherosclerosis may include any, or a combination of, the following:

• cardiac catheterization - with this procedure, x-rays are taken after a contrast agent is injected into an artery to locate the narrowing, occlusions, and other abnormalities of specific arteries.
• Doppler sonography - a special transducer is used to direct sound waves into a blood vessel to evaluate blood flow. An audio receiver amplifies the sound of the blood moving though the vessel. Faintness or absence of sound may indicate an obstruction in the blood flow.
• blood pressure comparison - comparing blood pressure measurements in the ankles and in the arms to determine any constriction in blood flow. Significant differences may indicate a narrowing of vessels which could be caused by atherosclerosis.
• MUGA/radionuclide angiography - a nuclear scan to see how the heart wall moves and how much blood is expelled with each heartbeat, while the patient is at rest.
• thallium/myocardial perfusion scan - a nuclear scan given while the patient is at rest or after exercise that may reveal areas of the heart muscle that are not getting enough blood.

Treatment for atherosclerosis:

Specific treatment will be determined by your physician based on:

• your age, overall health, and medical history
• extent of the disease
• the location of the blockage
• your signs and symptoms
• your tolerance for specific medications, procedures, or therapies
• expectations for the course of the disease
• your opinion or preference

Treatment may include:

• modification of risk factors
  Risk factors that may be modified include smoking, elevated cholesterol levels, elevated blood glucose levels, lack of exercise, poor dietary habits, and elevated blood pressure.
• medications
  Medications that may be used to treat carotid artery disease include:
  • antiplatelet medications - medications used to decrease the ability of platelets in the blood to stick together and cause clots. Aspirin, clopidogrel (Plavix®), ticlopidine (Ticlid®), and dipyridamole (Persantine®) are examples of antiplatelet medications.
  • anticoagulants - also described as "blood thinners," these medications work differently than antiplatelet medications to decrease the ability of the blood to clot. An example of an anticoagulant is warfarin (Coumadin®).
  • antihyperlipidemics - medications used to lower lipids (fats) in the blood, particularly Low Density Lipid (LDL) cholesterol. Statins are a group of antihyperlipidemic medications, and include simvastatin (Zocor®), atorvastatin (Lipitor®), and pravastatin (Pravachol®), among others. Bile acid sequestrants — colesevelam, cholestyramine and colestipol — and nicotinic acid (niacin) are two other types of medications that may be used to reduce cholesterol levels.
  • antihypertensives - medications used to lower blood pressure. There are several different groups of medications which act in different ways to lower blood pressure
• coronary angioplasty
  With this procedure, a balloon is used to create a bigger opening in the vessel to increase blood flow. Although angioplasty is performed in other blood vessels elsewhere in the body, percutaneous coronary intervention (PCI) refers to angioplasty in the coronary arteries to permit more blood flow into the heart. PCI is also called percutaneous coronary intervention (PTCA). There are several types of PCI procedures, including:
  • balloon angioplasty - a small balloon is inflated inside the blocked artery to open the blocked area.
  • atherectomy - the blocked area inside the artery is "shaved" away by a tiny device on the end of a catheter.
  • laser angioplasty - a laser used to "vaporize" the blockage in the artery.
  • coronary artery stent - a tiny coil is expanded inside the blocked artery to open the blocked area and is left in place to keep the artery open.
• coronary artery bypass
  Most commonly referred to as simply "bypass surgery," this surgery is often performed in people who have angina (chest pain) due to coronary artery disease (where plaque has built up in the arteries). During the surgery, a bypass is created by grafting a piece of a vein above and below the blocked area of a coronary artery, enabling blood to flow around the obstruction. Veins are usually taken from the leg, but arteries from the chest or arm may also be used to create a bypass graft.

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