Coronary heart disease (CHD) kills more than 385,000 people in the United States each year, and more than half of those who die suddenly have no previous symptoms. A new blood test that could reduce CHD-related illness and mortality by predicting the risk of future heart disease has been cleared by the US Food and Drug Administration (FDA). The PLAC Test for Lp-PLA2 screens for cardiovascular inflammation which can lead to a build up of rupture-prone plaque and result in a heart attack or stroke.
The PLAC Test for Lp-PLA2 is designed for people with two or more risk factors for cardiovascular disease who may have hidden risk or higher risk than expected for heart attack and stroke.
Although it has been approved for use in all adults with no history of heart disease, studies submitted by diaDexus, the medical diagnostics company that developed the test, and reviewed by the FDA, show that the test is better at predicting risk in women, particularly black women.
"A cardiac test that helps better predict future CHD risk in women, and especially black women, may help health care professionals identify these patients before they experience a serious CHD event, like a heart attack," says Alberto Gutierrez, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health.
According to diaDexus, 50 percent of heart attacks occur in patients with normal cholesterol. Statistics cited by the company suggest the majority of heart attacks and ischemic strokes are caused by plaque rupture in the arteries, which can occur when vascular inflammation is present.
The PLAC test measures a patient’s blood for levels of Lp-PLA2, a biological marker for vascular inflammation that plays a significant role in the formation of rupture-prone plaque.
If inflammation is present, it can cause the cap covering the plaque to thin and eventually rupture. When this happens, the flow of blood to the heart or brain can become blocked and lead to a heart attack or a stroke.
Patients with test results that show Lp-PLA2 activity greater than the level of 225 nanomoles per minute per milliliter (nmol/min/mL) are at increased risk for a CHD event, even if they have normal cholesterol (LDL) levels.
Knowing a patient's Lp-PLA2 level can help healthcare professionals identify whether the person is at risk for rupture-prone plaque. If so, they can use the results to help motivate the patient to adopt lifestyle changes, or recommend treatment options where necessary.