Cholesterol Tests

Subclinical Atherosclerosis

Subclinical atherosclerosis testing should be evaluated by an expert to avoid a false positive for heart disease -- and unnecessary treatment.

Subclinical atherosclerosis is a fancy term doctors use to describe the early stages of atherosclerosis that can occur throughout the body. Tests that measure subclinical atherosclerosis can be useful for people who want to know if they are at an increased risk of cardiovascular disease.

Significant evidence suggests that those who suffer from other atherosclerotic diseases, or atherosclerosis of peripheral -- not coronary -- arteries, are at an increased risk of coronary heart disease. This is because a person who has atherosclerosis in other blood vessels likely has atherosclerosis in the coronary arteries as well. The ankle-brachial blood pressure index (ABI) measures systolic blood pressure in the legs.

This test can diagnose peripheral arterial disease (PAD) -- a disease in which the arteries are narrowed and unable to carry enough blood to muscles in the legs while walking, which causes pain. Exercise or stress tests identify middle-aged men whose blood supply to the heart has been reduced due to narrowed arteries; however, these tests are not considered as reliable for other people.

Tests such as carotid sonography can determine something called carotid intimal medial thickness (IMT), or the severity of atherosclerosis affecting the carotid arteries that supply the brain with blood. Other tests can measure the amount of calcium, which is found in plaque, in the coronary arteries.

Coronary calcium, however, is not the same thing as a coronary blockage, and people who have high coronary calcium scores might still have "normal" results on stress tests. Although this test for presence of coronary calcium is not routinely recommended, it can be useful in people who are more likely to have coronary heart disease, and their doctor wishes to determine whether more intensive therapy may be beneficial.

For people who have two or more risk factors and a Framingham 10-year risk scoring of 10 to 20 percent, this test could result in a change in treatment. For those who have coronary calcium present, there are no studies to indicate that follow-up tests are of value. Indeed, it is entirely possible that with appropriate treatment that reduces risk factors, plaques could improve despite calcium deposits worsening.

And finally, in some young patients, especially smokers, a negative calcium score is not reassuring because they could have soft plaque that has not yet calcified. This test is best used to determine if treatment goals should be modified but should not be performed as a general screen.

The use of advanced lipid testing, measures of biomarkers, or tests for subclinical atherosclerosis can be useful in certain cases. For people at increased risk of cardiovascular disease (for example, someone with two risk factors, an LDL-cholesterol level between 100 and 129 mg/dL, and a Framingham 10-year risk scoring of 10 to 20 percent), the results of these tests might influence treatment decisions.

However, these tests can be costly, and unless they are evaluated by an expert, it's possible that they could be misinterpreted, resulting in further costly testing, and possibly unnecessarily aggressive treatment. Studies are ongoing to determine how best to use these tests and the information that they generate to benefit patients.

For all forms of cholesterol testing, accuracy is an issue. On the next page, find out what you can do to ensure the validity of your numbers.

For more information on cholesterol, see:

  • Cholesterol Levels: We all know there's "good" and "bad" cholesterol. Find out why you need more of one kind of cholesterol and less of the other.
  • Causes of High Cholesterol: Diet and DNA are the main causes of high cholesterol. Learn why the numbers might be high in your case.
  • Consequences of High Cholesterol: High cholesterol can lead to a heart attack. Learn more  about high cholesterol and heart attack and what other conditions high cholesterol contributes to.
  • How to Lower Cholesterol: Like many conditions, eating right and exercising helps control cholesterol. Learn what that means for you.
  • How Cholesterol Works: Cholesterol is essential to the body. Find out why we need it and how much is too much.

This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.