First blood test to help predict a patient's risk for ischemic stroke

The U.S. Food and Drug Administration (FDA) has approved the first blood test designed to help predict a patient's risk for ischemic stroke, the most common type of stroke and one of the nation's leading causes of long-term disability affecting approximately 700,000 people per year.

"This test provides a new tool to help us identify at-risk patients earlier, so we can start therapies in time to prevent a stroke altogether," said Christie Ballantyne, MD, director of the Center for Cardiovascular Disease Prevention at the Methodist DeBakey Heart Center in Houston.

The PLACTM test, developed by diaDexus, measures a blood enzyme called lipoprotein-associated phospholipase A2 (Lp-PLA2). Results from the National Heart Lung and Blood Institute's Atherosclerosis Risk in Communities (ARIC) study, conducted at the Methodist DeBakey Heart Center, demonstrated that people with elevated levels of this enzyme have a twofold risk of suffering an ischemic stroke associated with atherosclerosis over a period of 6 to 8 years. These findings are independent of traditional risk factors such as systolic blood pressure, smoking status and diabetes, body mass index, as well as levels of C-reactive protein (CRP), a risk factor for systemic inflammation.

While elevated cholesterol levels are a good predictor for heart disease, no such relationship has been established for stroke, even though both are related to blockages in blood vessels.

"Unlike cholesterol levels, Lp-PLA2 was a significant and independent predictor of ischemic stroke in the ARIC study," Ballantyne said. "Current guidelines for screening and prevention of heart disease do not include risk for stroke. The PLAC test will help physicians more accurately predict who is at risk for stroke, so that the individual can take proactive and preventative measures, such as lifestyle modification or therapeutic intervention, including statins and daily aspirin."

This study was supported by the National Institutes of Health (NIH) along with funding from GlaxoSmithKline.