Atherosclerosis

What Is It?

Atherosclerosis is a narrowing of the arteries that can significantly reduce the blood supply to vital organs such as the heart, brain and intestines. In atherosclerosis, the arteries are narrowed when fatty deposits called plaques build up inside. Plaques typically contain cholesterol from low-density lipoproteins (LDL), smooth-muscle cells and fibrous tissue, and sometimes calcium. As a plaque grows along the lining of an artery, it produces a rough area in the artery's normally smooth surface. This rough area can cause a blood clot to form inside the artery, which can totally block blood flow. As a result, the organ supplied by the blocked artery starves for blood and oxygen. The organ's cells may either die or suffer severe damage.

Atherosclerosis is the main cause of death and disability in industrialized nations, including the United States. This is because atherosclerosis is the underlying medical problem in most patients with any of the following illnesses:

• Coronary artery disease. In this chronic (long-lasting) disease, atherosclerosis narrows the coronary arteries, the arteries that supply blood to the heart muscle. This can lead to the chest pain called angina. It also increases the risk of a heart attack, which occurs when a coronary artery is blocked completely.

• Stroke. A blood clot (thrombus) may form inside a brain artery that has been narrowed by atherosclerosis. Once this thrombus forms, it cuts off the blood supply to part of the brain, causing a thrombotic stroke. Currently, about 75% of strokes in industrialized countries are thrombotic strokes.

• Abdominal angina and bowel infarction. When atherosclerosis narrows arteries that supply blood to the intestines, it causes a form of abdominal pain called abdominal angina. Complete, sudden blockage of intestinal blood supply can cause a bowel infarction. A bowel infarction is similar to a heart attack, but it involves the intestines rather than the heart.

• Atherosclerosis of the extremities. Atherosclerosis can narrow the major arteries that supply blood to the legs, especially the femoral and popliteal arteries. These two arteries are affected in 80% to 90% of people with this problem. The reduced blood flow to the legs may result in a crampy leg pain during exercise called intermittent claudication. If blood flow is compromised severely, parts of the leg may become pale or cyanotic (turn blue), feel cold to the touch and eventually develop gangrene.

• Other conditions. Atherosclerosis may be a factor in the development of an aortic aneurysm or renal artery stenosis (narrowing of the kidney arteries).

Factors that increase your risk of developing atherosclerosis include:

• High level of blood cholesterol (hypercholesterolemia)
• Low level of HDL (the "good cholesterol")
• High levels of C-reactive protein, a marker for inflammation
• High blood pressure (hypertension)
• Diabetes
• Family history of coronary artery disease at an early age
• Cigarette smoking
• Obesity
• Physical inactivity (too little regular exercise)
• Older age

Symptoms

Atherosclerosis usually doesn't cause any symptoms until blood supply to an organ is reduced. When this happens, symptoms vary, depending on the specific organ involved:

• Heart. Symptoms include the chest pain of angina and shortness of breath, sweating, nausea, dizziness or light-headedness, breathlessness or palpitations.

• Brain. When atherosclerosis narrows brain arteries, it can cause dizziness or confusion; weakness or paralysis on one side of the body; sudden, severe numbness in any part of the body; visual disturbance, including sudden loss of vision; difficulty walking, including staggering or veering; coordination problems in the arms and hands; and slurred speech or inability to speak. If symptoms disappear in less than 24 hours, the episode is called a transient ischemic attack (TIA). When atherosclerosis completely blocks the brain arteries and/or the above symptoms last longer, it's generally called a stroke.

• Abdomen. When atherosclerosis narrows the arteries to the intestines, there may be dull or cramping pain in the middle of the abdomen, usually beginning 15 to 30 minutes after a meal. Complete blockage of an intestinal artery causes severe abdominal pain, sometimes with vomiting, diarrhea or abdominal swelling.

• Legs. Narrowing of the leg arteries causes cramping pain in the leg muscles, especially during exercise. If narrowing is severe, there may be pain at rest, cold toes and feet, pale or bluish skin, and hair loss on the legs.

Diagnosis

Your doctor will review your medical history, your current symptoms and any medications you are taking.

Your doctor will ask you about your family history of heart disease, stroke and other circulatory problems, and your family history of high blood cholesterol. He or she will ask about cigarette smoking, your diet, and how much exercise you get,

Your doctor will measure your blood pressure and heart rate. He or she will examine you, paying special attention to your circulation. The exam includes feeling for pulses in your neck, wrists, groin and feet. Your doctor may check the blood pressure in your legs, to compare it to the pressure in your arms. The ratio of your blood pressure at your ankle to the blood pressure inside your elbow is called an ankle-brachial index or ABI.

Signs of poor impaired circulation include:

• Weak pulses

• Cool skin that is pale or blue in the lower legs and feet

• Bruits (the rough sound of turbulent blood flow through narrowed arteries) heard with a stethoscope in the neck, abdomen and groin.

• An ABI of 0.9 or lower

Your doctor will order blood tests to measure your total, LDL and HDL cholesterol levels, triglyceride level, and fasting blood sugar. A routine electrocardiogram (EKG) occasionally will uncover electrical changes in the heart that indicate poor blood flow to the heart muscle. Your doctor may order an EKG performed during an exercise stress test if you have any symptoms suggestive of coronary artery disease.

Expected Duration

Atherosclerosis is a long-term condition that continues to worsen over many decades without changes in lifestyle and medication if neccessary.

Prevention

You can help to prevent atherosclerosis by changing your risk factors for the illness. You should practice a lifestyle that promotes good circulation and combats atherosclerosis:

• Avoid cigarette smoking. If you smoke, it is essential that you quit.

• Maintain a healthy weight. Obesity, especially a concentration of body fat around the waist, has been linked to unhealthy levels of HDL cholesterol and triglycerides.

• Eat a healthy diet that is rich in vegetables and fruits. Avoid saturated and trans fats. Use monounsaturated (olive) and polyunsaturated (sunflower, safflower, peanut, canola) oils for cooking. Dietary protein should come primarily from fish and plant sources (soy, beans, legumes).

• Exercise regularly.

• Control high blood pressure. You may have to take medication to do this. If you have never been diagnosed with high blood pressure, you should have it checked every two years.

• If you have diabetes, you need to work even harder on controlling weight, exercising more, lowering LDL cholesterol and triglyceride levels, and keeping blood pressure less than 130/85.

• If you do not have diabetes, you should have a fasting blood sugar test every few years if you have risk factors for diabetes (being overweight, having high blood pressure or high cholesterol) starting at age 45.

• Work with your doctor to maintain proper cholesterol levels. If you have never been diagnosed with cholesterol problems, you should have your cholesterol checked every five years starting at age 20.

Treatment

There is no cure for atherosclerosis, but treatment can slow or halt the worsening of the disease. The major treatment goal is to prevent significant narrowing of the arteries so that symptoms never develop and vital organs are never damaged. To do this, you would begin by following the healthy lifestyle outlined above. If you have high cholesterol that cannot be controlled by diet and exercise, medication may be necessary. There are currently five classes of cholesterol-lowering medications:

• HMG-CoA reductase inhibitors, including lovastatin (Mevacor), simvastatin (Zocor), pravastatin (Pravachol), fluvastatin (Lescol), rosuvastatin (Crestor) and atorvastatin (Lipitor). HMG-CoA reductase inhibitors block an enzyme called HMG-CoA reductase, which controls the production of cholesterol in the liver.
• Bile acid-binding resins, including cholestyramine (Questran) and colestipol (Colestid)
• Niacin
• Fibrates, including gemfibrozil (Lopid) and fenofibrate (Tricor)
• Cholesterol-absorption inhibitors, which is the newest class of cholesterol-lowering agents. Ezetimibe (Zetia) is currently the only one on the market.

Once symptoms of atherosclerosis-related organ damage develop, the specific treatment depends on the organ involved:

• Heart. Treatments for coronary artery disease include medications to manage symptoms of angina (nitrates, beta-blockers, calcium channel blockers) and prevent heart attacks (aspirin and beta-blockers); balloon angioplasty often with wire mesh stents; and, less commonly, coronary artery bypass surgery.

• Brain. Treatments to help prevent transient ischemic attacks (TIAs) and stroke include antiplatelet medications such as aspirin, dipyridamole and clopidogrel (Plavix), and anticoagulant medications such as warfarin and heparin.

• Abdomen. When atherosclerosis narrows arteries that supply the bowel, the patient may be treated with balloon angioplasty with or without stents or a bypass arterial graft.

• Legs. The mainstays of treatment for intermittent claudication are quitting smoking, exercise (usually a walking program) and aspirin. People with severe arterial narrowing may be treated with balloon angioplasty with or without stents, laser angioplasty, atherectomy or bypass grafts.

When to Call a Professional

It is possible to have atherosclerosis for many years without having symptoms. If you experience symptoms of an atherosclerosis-related medical condition, contact a doctor immediately.

Prognosis

Atherosclerosis leads to the number one cause of death in the United States and many other countries for both men and women: coronary artery disease. However, people with atherosclerosis are living longer with better quality of life than ever before. For many, this disease can be prevented. Even those people genetically programmed for atherosclerosis can delay the beginning and worsening of the disease with a healthy lifestyle, the right foods and medication to lower LDL cholesterol.

Additional Info

National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD 20824-0105
Phone: 301-592-8573
TTY: 240-629-3255
Fax: 240-629-3246
http://www.nhlbi.nih.gov/

American Heart Association (AHA)
7272 Greenville Ave.
Dallas, TX 75231
Toll-Free: 800-242-8721
http://www.americanheart.org/

American College of Cardiology
Heart House
9111 Old Georgetown Road
Bethesda, MD 20814-1699
Phone: 301-897-5400
Toll-Free: 800-253-4636, ext. 694
Fax: 301-897-9745
http://www.acc.org/