Illustration by Maria Rendon
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Guide to Heart Tests
By Melissa Hendricks, March-April 2004
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Doctors are still debating which of the new heart tests are right for which
patients. But in the meantime, knowledge is power. If you don't already
know whether your risk of a heart attack is low, medium, or high, you can find
out from your doctor, who will calculate it using measurements such as blood
pressure and cholesterol levels. See below for a quick guide to which of the
new tests might benefit you. Print and save our web-exclusive chart for tracking heart tests that your doctor might recommend.
Ankle-brachial index
- What: A probe measures the ratio of the blood pressure in the ankle to the
blood pressure in the arm's main artery. An index of less than 0.9
indicates a blockage in a vessel in the legs, which suggests blockages
elsewhere, including the coronary arteries.
- Who: People over age 60 who have at least one risk factor for heart
disease; smokers; diabetics.
Carotid ultrasound
- What: Uses sound waves to measure thickness of the walls of the carotid
arteries in the neck; thicker walls suggest a higher risk of heart
disease.
- Who: People with a medium risk of heart disease; smokers; diabetics.
C-reactive protein (CRP)
- What: Blood test for protein that accompanies inflammation; high levels
could indicate heart disease.
- Who: People with a medium risk of heart disease.
Fibrinogen
- What: Blood test for protein essential to normal clotting. Excess
fibrinogen may cause blood clots in arteries or be a sign of atherosclerosis.
High levels associated with heart disease.
- Who: People with a medium risk of heart disease.
Homocysteine
- What: Blood test for the amino acid homocysteine. Elevated levels are
sometimes associated with heart disease and stroke.
- Who: People whose close relatives had heart disease at a young age; people
with a history of heart problems but no other risk factors.
Lipoprotein (a), Lp(a)
- What: Blood test for a fat, or lipid. Lp(a) contributes to atherosclerosis
and may increase the risk of blood clots. Can be elevated even if other
cholesterol levels are normal.
- Who: People with a family history of heart disease or who may carry a gene
for high cholesterol; smokers; diabetics; people who have had heart
disease.
Magnetic Resonance Imaging (MRI)
- What: Uses radio waves and magnetic field to show motion of the heart or
images of blood vessels. In the future, it may be used to show
atherosclerosis.
- Who: People with congenital heart disease, irregular heart rhythms, chest
pain, or a potential aortic aneurysm.
Ultrafast CT scan, or Electron Beam Computed
Tomography (EBCT)
- What: Imaging test that uses x-rays. Detects calcium in the arteries, which
indicates the degree of atherosclerosis.
- Who: People with a medium or uncertain risk of heart disease who have a
risk factor such as smoking.
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