Coronary Artery Disease
(CAD; Coronary Atherosclerosis; Silent MI; Coronary Heart Disease; Ischemic Heart Disease; Atherosclerosis of the Coronary Arteries)
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
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:
- Sex: male (men have a greater risk of heart attack than women)
- Age: 45 and older for men, 55 and older for women
- Heredity: strong family history of heart disease
- Obesity and being overweight
- Smoking
- High blood pressure
- Sedentary lifestyle
- High blood cholesterol (specifically, high LDL cholesterol, and low HDL cholesterol)
- Diabetes
- Depression*³
Other risk factors include:
- Stress
- Excessive alcohol use
- Metabolic syndrome —combination of high blood pressure, abdominal obesity, and insulin resistance
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
- It is unrelieved by rest or nitroglycerin
- Severe angina
- Angina that begins at rest (with no activity)
- Angina that lasts more than 15 minutes
- 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.
- Warfarin (Coumadin)
- Ticlopidine (Ticlid)
- Clopidogrel (Plavix)
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.
RESOURCES:
American Heart Association
http://www.americanheart.org/
National Heart, Lung, and Blood Institute
http://www.nhlbi.nih.gov/
CANADIAN RESOURCES:
Heart and Stroke Foundation of Canada
http://ww2.heartandstroke.ca/
Heart Healthy Kit: Public Health Agency of Canada
http://www.phac-aspc.gc.ca/
References:
Arora RR, Chou TM, et al. The multicenter study of enhanced external counterpulsation (MUST-EECP): effect of EECP on exercise-induced myocardial ischemia and anginal episodes. J Am Coll Cardiol . 1999;33:1833-1840.
Boden WE, O'Rourke RA, Teo KK, et al. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med . 2007;356:1503-1516.
Dambro MR. Griffith's 5-Minute Clinical Consult. Philadelphia, PA: Lippincott Williams & Wilkins; 2001.
Fuster V, Hurst JW. Hurst's The Heart . 11th ed. New York, NY: McGraw-Hill;2004.
GWTG-CAD fact Sheet. American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=3040028 . Accessed July 20, 2008.
Lilly LS. Braunwald’s Heart Disease . 7th ed. Philadelphia, PA: Elsevier Saunders;2004.
What is coronary artery disease? National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov . Accessed July 20, 2008.
* 1 4/10/2007 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Boden WE, O'Rourke RA, Teo KK, et al. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med. 2007 Mar 26.
* 2 11/7/2007 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Bravata DM, Gienger AL, McDonald KM, et al. Systematic Review: The comparative effectiveness of percutaneous coronary interventions and coronary artery bypass graft surgery. Ann Intern Med. 2007 Nov 20.
* 3 1/6/2009 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Surtees PG, Wainwright NW, Luben RN, Wareham NJ, Bingham SA, Khaw KT. Depression and ischemic heart disease mortality: evidence from the EPIC-Norfolk United Kingdom prospective cohort study. Am J Psychiatry. 2008;165:515-523.
Last reviewed January 2009 by Igor Puzanov, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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