Atherosclerosis [1]

 

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 narrowing of the arteries is caused by the formation of plaques, which 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 trigger the formation of a blood clot inside the artery, causing a total blockage of blood flow. As a result, the organ supplied by the blocked artery starves for blood and oxygen, and the organ’s cells may either die or suffer severe damage.

Atherosclerosis is the major 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 disease, atherosclerosis narrows the coronary arteries, the arteries supplying blood to the heart muscle. As the coronary arteries narrow, the chest pain called angina may be triggered. And the risk of a heart attack (myocardial infarction), which occurs when a coronary artery is blocked completely, is increased. Coronary artery disease currently affects 11 million people in the United States.
  • 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 percent 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 percent to 90 percent 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”)
  • Hypertension (high blood pressure)
  • 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 produces no symptoms until arterial narrowing significantly reduces blood supply to an organ. 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 lightheadedness, breathlessness or palpitations.
  • Brain — When atherosclerosis narrows brain arteries, it can cause headache; 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, vomiting, diarrhea or constipation.
  • Legs — Narrowing of the leg arteries produces crampy pain in the leg muscles, especially during exercise. If narrowing is severe, there may be hair loss on the legs, thickening of the toenails, skin that is cool and a pale or blue color.

Diagnosis

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, exercise, alcohol use and symptoms of atherosclerosis. He or she also will measure your blood pressure and check your pulse in your neck and feet.

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

If you have no symptoms of any of the medical conditions related to atherosclerosis, your doctor will perform a physical examination, and look for signs of poor circulation. In general, these can include bruits (the rough sound of turbulent blood flow through narrowed arteries) heard with a stethoscope in the neck, abdomen and elsewhere; weakened pulses, especially in the groin, legs and feet; and cool skin that is pale or blue in the legs.

Your doctor will order blood tests to measure your total, LDL and HDL cholesterol levels, triglyceride level, and fasting blood sugar. Although a routine electrocardiogram (EKG) occasionally will uncover electrical changes in the heart that indicate poor blood flow to the heart muscle, these are more likely to be discovered on an EKG performed during an Exercise stress test. Other diagnostic tests may be needed to confirm impaired circulation to the heart, brain, and legs.

Expected Duration

Atherosclerosis is a long-term condition that progresses over many decades.

Prevention

You can help prevent atherosclerosis by modifying your risk factors for the illness. More specifically, you should practice a lifestyle that promotes good circulation and combats atherosclerosis:

  • Avoid cigarette smoking.
  • Maintain a healthful 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. Anti-hypertensive medication may be necessary.
  • 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.
  • Work with your doctor to optimize your cholesterol levels.

Treatment

There is no cure for atherosclerosis, but the progression can be slowed and even halted. The major treatment goal is to prevent significant arterial narrowing 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 different classes of cholesterol-lowering medications:

  • HMG-CoA reductase inhibitors, including lovastatin (Mevacor), simvastatin (Zocor), pravastatin (Pravachol), fluvastatin (Lescol) 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 usually 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. In severe arterial narrowing, patients 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. Smoking cessation is a must, no matter how old you are. You will need to know your blood pressure, blood cholesterol profile, and fasting blood sugar to get a picture of your atherosclerosis risk. Blood pressure should be checked at least every couple of years. Cholesterol profiling should be done every five years starting at age 20. If you are at average risk for diabetes, then fasting blood-sugar testing begins at age 45. 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 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 is a preventable disease. Even those people genetically programmed for atherosclerosis can delay the onset and progression with a healthy lifestyle, the right foods, and medication to lower LDL cholesterol.

 

Johns Hopkins patient information

Last revised: December 4, 2012
by Amalia K. Gagarina, M.S., R.D.

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