Blood test to predict coronary heart disease risk approved by FDA

Coronary heart disease is the primary cause of death for both men and women in the USA. Now, the US Food and Drug Administration have approved a new test that can predict an individual's risk of the condition, and the test is hailed as particularly effective for black women.

The FDA say the test predicts CHD risk by measuring Lp-PLA2 activity in patients' blood - a biomarker of vascular inflammation.

According to the Food and Drug Administration (FDA), the test - called the PLAC Test for Lp-PLA2 - has been cleared for use in both men and women with no history of heart disease, but studies have shown it is more accurate in predicting coronary heart disease risk (CHD) in women.

The test works by measuring the activity of Lp-PLA2 (lipoprotein-associated phospholipase A2) - an enzyme that is an indicator of vascular inflammation - in a blood sample. 

Vascular inflammation is a sign of plaque accumulation in the arteries, and this build-up of plaque can clog the arteries and cause CHD.

Patients with Lp-PLA2 activity over 225 nanomoles per minute per milliliter (nmol/min/mL) in their blood are deemed high risk of a CHD event, such as a heart attack or stroke. Patients with Lp-PLA2 activity below 225 nmol/min/mL are classed as lower risk for a CHD event.

CHD events more common in black women with higher Lp-PLA2 activity

To reach their decision of whether to approve the PLAC Test for Lp-PLA2, the FDA conducted a review of all available studies on the technique.

Fast facts about CHD

• CHD kills around 375,000 Americans each year
• Risk factors for CHD include high blood pressure, smoking, high cholesterol and high blood glucose
• Women over the age of 55 and men over the age of 45 are most at risk of CHD.

Their review included the PLAC Test for Lp-PLA2 Activity Validation Study, in which the test was administered on 4,598 participants aged 45-92 years who had no history of CHD. Of these participants, 58.3% were women and 41.5% were black.

The study researchers followed the participants for an average of 5.3 years, during which time they recorded the occurrence of CHD events among each individual.

The results of the study revealed that 7% of participants with Lp-PLA2 activity higher than 225 nmol/min/mL experienced a CHD event, compared with only 3.3% of participants with Lp-PLA2 activity lower than 225 nmol/min/mL.

On analyzing the team's data by subgroups, the FDA found that the rate of CHD events was much higher among black women whose Lp-PLA2 activity levels were higher than 225 nmol/min/mL, compared with other subgroups with similar Lp-PLA2 activity. CHD events were also found to be more common among women with Lp-PLA2 activity levels over 225 nmol/min/mL than men with such levels.

The FDA note that, as a result, the test is labeled with different performance information for black women, white women, black men and white men.

Hopes that the test will reduce CHD-related mortality and morbidity in women

Heart disease is responsible for 1 in 4 female deaths in the US, and CHD is the most common form of the condition.

According to the Centers for Disease Control and Prevention (CDC), around 64% of women who die from CHD have no previous symptoms of the condition. The FDA hope the PLAC Test for Lp-PLA2 will aid early detection of CHD in this population.

"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.

We hope the clearance of this test will improve preventative care and reduce CHD-related mortality and morbidity in these patients."

References:

FDA news release, accessed 16 December 2014.
Additional source: PLAC Test for Lp-PLA2, accessed 16 December 2014.
Additional source: CDC, women and heart disease, accessed 16 December 2014.
Additional source: National Heart, Lung and Blood Institute, coronary heart disease, accessed 16 December 2014.