When your healthcare provider determines that you are at a moderate to high risk of developing CVD or of having an ischemic stroke; when you have a family history of CVD or CHD
A blood sample drawn from a vein in your arm
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that appears to play a role in the inflammation of blood vessels and is thought to help promote atherosclerosis. This test measures the amount or activity of Lp-PLA2 in the blood.
Some recent studies have shown that Lp-PLA2 is an independent risk marker for cardiovascular disease (CVD), including coronary heart disease (CHD), and ischemic stroke. In these studies, increased concentrations of Lp-PLA2 were seen in many people who were diagnosed with CHD and ischemic stroke, regardless of other risk factors. These findings make this relatively new test potentially useful as one of a growing number of cardiac risk markers that are used to help determine a person's risk of developing CVD.
CVD causes more deaths in the U.S. each year than any other cause, according to the Centers for Disease Control and Prevention. CHD and ischemic stroke are both associated with the buildup of fatty plaque deposits in the arteries that can lead to blockages in blood vessels and to heart attacks or brain damage. There are a variety of risk factors that have been identified as being associated with both conditions, including high blood pressure, diabetes, metabolic syndrome, smoking, obesity, high cholesterol levels, increased LDL (low-density lipoprotein, the "bad cholesterol"), and decreased HDL (high-density lipoprotein, the "good cholesterol").
Many people who have one or more of the commonly recognized risk factors will eventually develop CVD, but a significant number of people who have few or none of these risk factors will also develop CVD. This has lead researchers to look for additional markers that might identify those at increased risk of CVD.
In addition to the traditional risk factors listed above, a low level of chronic, systemic inflammation and blood vessel (vascular) inflammation are thought to contribute to overall risk for developing CVD. The hs-CRP test is associated with systemic inflammation; high levels are associated with increased CVD risk. The Lp-PLA2 test is associated with vascular inflammation, and high levels are thought to increase the chance of cardiovascular events, including heart attack or stroke. High levels of Lp-PLA2 is also associated with vascular complications in people with diabetes, such as kidney disease.
How is it used?
Lp-PLA2 is an enzyme that appears to play a role in the inflammation of blood vessels and is thought to help promote atherosclerosis. Some recent studies have shown that Lp-PLA2 is an independent risk marker for cardiovascular disease (CVD), including CHD and ischemic stroke.
The test would typically be used to evaluate an individual who is at a moderate to elevated risk for CHD or stroke, someone with one or more other risk factors. For instance, it may be ordered when someone has normal or minimally elevated lipid levels, borderline high blood pressure (hypertension), or metabolic syndrome.
An Lp-PLA2 test may sometimes be used along with an hs-CRP test to evaluate a person's level of underlying inflammation associated with CVD risk. However, unlike hs-CRP, the Lp-PLA2 test is not affected by conditions other than CVD that can cause general inflammation, so it may be used when someone has an inflammatory condition, such as arthritis.
Lp-PLA2 is a relatively new test that is not frequently ordered and its full clinical usefulness has yet to be established. It is intended to give additional information, not to replace cholesterol and other lipid level testing.
Some researchers are exploring whether treatment to lower Lp-PLA2 levels will lower a person's risk of CHD and ischemic stroke. However, several studies on drugs that inhibit Lp-PLA2 activity (such as darapladib) found that inhibition had little or no effect on reducing risk of CHD. If future studies found the risk of CVD and stroke is decreased when Lp-PLA2 is lowered, then the Lp-PLA2 test may be ordered more frequently and be used to monitor a person's response to treatment.
When is it ordered?
What does the test result mean?
A significantly elevated Lp-PLA2 level indicates an increased risk for developing CHD or of having an ischemic stroke and provide a healthcare practitioner with additional information about the tested person's overall risk.
A low or normal Lp-PLA2 means that this factor does not contribute to the tested person's risk of CVD.
The test is not diagnostic of CHD or ischemic stroke; it is a risk indicator. Many people with increased concentrations will not develop these conditions, and some with normal levels will.
Is there anything else I should know?
The Lp-PLA2 test is not widely available. In most cases, the blood sample will be sent to a reference laboratory and results will be available within a few days.
Should everyone have an Lp-PLA2 test?
It is not currently indicated or recommended by major health organizations as a screen for the general population or recommended yet as a primary cardiac risk marker. Your healthcare provider can help you determine the best tests to determine your risk of developing CVD and provide you with information about changes you can make to lower your risk.
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