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Intravascular ultrasound (IVUS) is a test that employs high frequency sound waves in vascular tissues, particularly the coronary arteries. The coronary arteries are the blood vessels that supply blood and oxygen to the heart. IVUS may also be referred to as ultrasound of the coronary arteries or endovascular ultrasound.
Ultrasound waves work by reflecting moving pictures of an organ or tissue into a computer which can be viewed by a medical worker. In IVUS a tiny wand is attached to a hollow flexible tube or catheter that is inserted through the large artery in the groin all the way to the coronary arteries. With this technique an inside view of the walls of the arteries are seen. This is especially important in obtaining a picture of the condition of these vessels that are vulnerable to changes in diameter.
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Why is IVUS Important in Coronary Artery Disease?
The heart is a highly muscular organ that pumps blood continuously to all part of the body. It is totally dependent on the small coronary arteries that deliver oxygenated blood to it. Slight changes in the diameters of the coronary vessels may affect its efficiency in doing its function. Therefore, factors that can decrease their size such as plaques or cholesterol build-up within their walls can cause heart disease, commonly called coronary artery disease (CAD). This puts the patient at risk for a heart attack.
Ultrasound of the coronary arteries is done most commonly as an aid to angioplasty with stent placement, a procedure which expands and keeps the blocked arteries open. This procedure, also called cardiac catheterization, is done in patients at high risk for a heart attack or stroke because of the significant reduction in the diameters of the arteries. IVUS aids in:
- Viewing and identifying blocked arteries
- Ascertaining correct placement of the stent or catheter
- Checking the patency of the stent and indicating if there is blockage of the stent
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Risks of Intravascular Ultrasound
Together with angioplasty and cardiac catheterization, ultrasound of the coronary arteries is usually safe when done by experienced personnel. Over one million people undergo these procedures in the United States every year and very few complications occur. Risks for complications are generally higher in patients older than 75 years old, in women, in those with advanced heart disease and in those with diabetes and kidney disease.
Possible complications of these procedures are:
- Heart attack
- Allergic reaction and kidney failure due to the dye used in the procedure
- Arrythmias (irregular hear rhythm)
- Damage to the blood vessels
- Damage to the heart
- Blood clots
In general IVUS itself does not increase the risks of these therapeutic procedures for coronary artery disease, nor does it prolong hospital stay. The outcome of these procedures depends on the general health status of the patient and the expertise of the medical personnel.
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Medline Plus, “Intravascular Ultrasound", http://www.nlm.nih.gov/medlineplus/ency/article/007266.htm
NHLBI, “What Is Coronary Angioplasty?" http://www.nhlbi.nih.gov/health/dci/Diseases/Angioplasty/Angioplasty_WhatIs.html