DALLAS, Nov. 14 /PRNewswire/ -- diaDexus today announced results from a study demonstrating that lipoprotein-associated phospholipase A2 (Lp-PLA2) is a strong independent predictor of Coronary Artery Disease (CAD) in women, particularly older women (65 or older) where high levels of Lp-PLA2 conferred a nearly three-fold increase in risk of CAD. These results were presented Sunday at the American Heart Association Scientific Sessions in Dallas. An additional study describing the effect hormone therapy has on Lp-PLA2 levels in women was also presented.
Cardiovascular disease, including CAD and stroke, is the leading cause of death for women in the United States, and 64 percent of women who died suddenly of CAD had no previous symptoms of the disease. A growing body of evidence suggests that inflammation plays a key role in the development of atherosclerosis, from the creation of arterial plaque through acute cardiovascular event. Therefore, novel inflammatory risk factors like Lp-PLA2 may improve the identification of patients at risk for cardiovascular events, like heart attack and stroke.
“Many of the commonly used predictive models for developing cardiovascular disease, including the Framingham risk score, do not accurately identify women who later develop cardiovascular disease. This study found that Lp-PLA2 had a very strong predictive value in women over 65 years old,” stated Robert L. Wolfert, Ph.D., Executive Vice President, Diagnostics at diaDexus. “These results further support Lp-PLA2 as an important predictor of CAD and may help us identify women at risk for having a life-threatening cardiovascular event in order to initiate preventive strategies to avoid such an event.”
“Sex and Age-Related Differences in Levels of Lipoprotein-Associated Phospholipase A2"
The researchers of the study, from LDS Hospital Cardiology in Salt Lake City, Utah, measured the Lp-PLA2 blood plasma levels of 1045 men and 448 women (average age 63 years) using the PLAC(R) test. All patients underwent coronary angiography to diagnose the presence of CAD. Lp-PLA2 was found to be predictive for CAD in both younger (<65) women, with an Odds Ratio (OR) indicating a 2.3-fold risk of disease and in men (OR=1.8). Lp-PLA2 was an even stronger predictor of disease in women over 65 years (OR=2.7) and was more accurate than CRP. In this study, CRP was found to be a better predictor of CAD than Lp-PLA2 in men over the age of 65.
“Association of Oral Contraceptive Intake and Different Hormone Replacement Therapies on Lipoprotein-associated Phospholipase A2 Plasma Concentrations in Apparently Healthy Women: MONICA Augsburg Study”
Data from a second study presented at the AHA Scientific Sessions demonstrated that estrogen and progesterone have a modulatory effect on plasma levels of Lp-PLA2. A survey of 838 premenopausal women (age 25-44 years) and 734 postmenopausal women (age 45-64 years) participating in the MONICA Augsburg study (1994-1995), found that levels of Lp-PLA2 were significantly decreased in the younger women who were taking oral contraceptives vs. those who were not. In the postmenopausal women, Lp-PLA2 levels were similarly lower in women taking oral estrogen monotherapy, but higher in those taking either transdermal estrogen or combination estrogen-progesterone therapy (oral or transdermal).
“Since Lp-PLA2 is directly involved in the development of atherosclerotic plaque, these findings suggest that various forms of hormonal therapy, some raising and others lowering Lp-PLA2 levels in the blood, may have differential effects on a woman’s risk for cardiovascular disease,” stated Richard B. Lanman, M.D., Chief Medical Officer at diaDexus.
About Lp-PLA2
Lp-PLA2 (lipoprotein-associated phospholipase A2) is an enzyme that is implicated in the vascular inflammatory pathway that leads to plaque formation and atherosclerosis. Previous hypotheses on the cause of coronary heart disease focused around lipid accumulation within the arterial walls. Increasing evidence now suggests that atherosclerosis is largely an inflammatory disease. Multiple published studies in peer-reviewed journals show a statistically significant relationship between elevated Lp-PLA2 and the risk of a major cardiovascular event.
About the PLAC Test
The PLAC test has been cleared by the FDA as an aid in predicting an individual’s risk for a coronary event and ischemic stroke associated with atherosclerosis, in conjunction with clinical evaluation and patient risk assessment. The PLAC test is currently available through laboratories nationwide, including Quest Diagnostics Incorporated, Mayo Medical Laboratories, ARUP Laboratories and Berkeley HeartLab. For more information about the PLAC test, visit www.plactest.com.
About diaDexus
diaDexus, a privately held biotechnology company based in South San Francisco, California, is focused on the discovery, development and commercialization of novel, patent-protected diagnostic and therapeutic products with high clinical value. More information about the company may be found at www.diaDexus.com.
diaDexus
CONTACT: Patrick Plewman of diaDexus, Inc., +1-650-246-6400; or CarolynBumgardner Wang of WeissComm Partners, +1-415-225-5050, orcarolyn@weisscommpartners.com, for diaDexus, Inc.