Definition

Coronary arteries bring oxygen rich blood to the heart muscle. Coronary artery disease (CAD) is blockage of these arteries. If the blockage is complete, areas of the heart muscle may be damaged. In severe case the heart muscle dies. This can lead to a heart attack, also known as a myocardial infarction (MI).

Coronary artery disease is the most common form of heart disease. It is the leading cause of death worldwide.

Coronary Artery Disease

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2009 Nucleus Medical Art, Inc.

Causes

Causes include:

  • Thickening of the walls of the arteries feeding the heart muscle
  • Accumulation of fatty plaques within the coronary arteries
  • Sudden spasm of a coronary artery
  • Narrowing of the coronary arteries
  • Inflammation within the coronary arteries
  • Development of a blood clot within the coronary arteries that blocks blood flow

Risk Factors

Major risk factors include:

Other risk factors include:

Symptoms

CAD may progress without any symptoms.

Angina is chest pain that comes and goes. It often has a squeezing or pressure-like quality. It may radiate into the shoulder(s), arm(s), or jaw. Angina usually lasts for about 2-10 minutes. It is often relieved with rest. Angina can be triggered by:

  • Exercise or exertion
  • Emotional stress
  • Cold weather
  • A large meal
Chest pain may indicate more serious unstable angina or a heart attack if:

  • It is unrelieved by rest or nitroglycerin
  • Severe angina
  • Angina that begins at rest (with no activity)
  • Angina that lasts more than 15 minutes
Accompanying symptoms may include:
  • Shortness of breath
  • Sweating
  • Nausea
  • Weakness

Immediate medical attention is needed for unstable angina. CAD in women may cause less classic chest pain. It is likely to start with shortness of breath and fatigue.

Diagnosis

If you go to the emergency room with chest pain, some tests will be done right away. The tests will attempt to see if you are having angina or a heart attack. If you have a stable pattern of angina, other tests may be done to determine the severity of your disease.

The doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include:

  • Blood tests—to look for certain substances in the blood called troponins which help the doctor determine if you are having a heart attack
  • Electrocardiogram (ECG, EKG)— records the heart's activity by measuring electrical currents through the heart muscle, and can reveal evidence of past heart attacks, acute heart attacks, and heart rhythm problems
  • Echocardiogram —uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart, giving information about the structure and function of the heart
  • Exercise stress test —records the heart's electrical activity during increased physical activity
  • Nuclear stress test—the heart is observed while exercising and radioactive material highlights impaired blood flow to help locate problem areas
  • Coronary calcium scoring—a type of x-ray called a CAT scan that uses a computer to look for the presence of calcium in the heart arteries
  • Coronary angiography —x-rays taken after a dye is injected into the arteries to allows the doctor to look for abnormalities in the arteries

Treatment

Treatment may include:

Nitroglycerin

This medicine is usually given during an attack of angina. It can be given as a tablet that dissolves under the tongue or as a spray. Longer-lasting types can be used to prevent angina before an activity known to cause it. These may be given as pills or applied as patches or ointments.

Blood-Thinning Medications

A small, daily dose of aspirin has been shown to decrease the risk of heart attack. Ask your doctor before taking aspirin daily.

Beta-Blockers, Calcium-Channel Blockers, and ACE-Inhibitors

These may help prevent angina. In some cases, they may lower the risk of heart attack.

Medications to Lower Cholesterol

These medications may prevent the progression of CAD. They may even improve existing disease.

Evidence shows that lowering cholesterol has a positive effect on prevention of CAD events.

Revascularization

Patients with severe blockages in their coronary arteries may benefit from procedures to immediately improve blood flow to the heart muscle:

  • Percutaneous coronary interventions (PCI)—such as balloon angioplasty , in some cases, a wire mesh stent is placed to hold the artery open
  • Coronary artery bypass grafting (CABG) —segments of vessels are taken from other areas of the body and are sewn into the heart arteries to reroute blood flow around blockages

Some studies have shown that CABG may be more effective than PCI. Lifestyle changes and intensive medication may also be just as effective as PCI. * 2 * 1

Options for Refractory Angina

For patients who are not candidates for revascularization procedures but have continued angina despite medication, options include:

  • Enhanced external counterpulsation (EECP)—large air bags are inflated around the legs in tune with the heart beat. The patient receives 5 one-hour treatments per week for seven weeks. This has been shown to reduce angina and may improve symptom-free exercise duration.
  • Transmyocardial revascularization (TMR)—surgical procedure done with laser to reduce chest pain.
  • Researchers are also studying gene therapy as a possible treatment.

Prevention

To reduce your risk of getting coronary artery disease:

  • Maintain a healthy weight.
  • Begin a safe exercise program with the advice of your doctor.
  • If you smoke, quit .
  • Eat a healthful diet. It should be low in saturated fat. It should also be rich in whole grains, fruits, and vegetables.
  • Treat your high blood pressure and/or diabetes.
  • Treat high cholesterol or triglycerides.