The research was presented by Dr. Christie M. Ballantyne, director of the Center for Cardiovascular Disease Prevention at Baylor College of Medicine and the Methodist DeBakey Heart Center, Houston. Dr. Ballantyne and his team used the PLAC™> test to determine the level of Lp-PLA2 in the participants' blood. The PLAC test, developed by diaDexus, Inc., a privately held biotechnology company based in South San Francisco, provides a quantitative measurement of Lp-PLA2, an enzyme commonly found in human blood plasma and arterial plaques. Lp-PLA2 was previously described as a novel risk factor for cardiac events in the October 19, 2000 issue of the New England Journal of Medicine.
The prospective, case-cohort study involved 12,819 apparently healthy middle-aged American men and women in the Atherosclerosis Risk in Communities (ARIC) study. Dr. Ballantyne and his team examined the relationship between Lp-PLA2, hs-CRP, traditional risk factors and the incidence of CHD events over the course of six years, stratified by LDL. The research team determined that mean levels of Lp-PLA2 and hs-CRP were higher in the 609 cases of CHD events than the 741 non-cases, after adjustment for age, sex and race.
The study also determined that for individuals with LDL cholesterol below the median (130 mg/dL), both Lp-PLA2 and hs-CRP were significantly, and independently, associated with CHD in fully adjusted models. Patients in this study with 'normal' LDL levels (<130 mg/dL), but elevated levels of both CRP and Lp-PLA2, were found to have a significantly increased risk of a cardiac event.
"Unfortunately, many people with 'normal' LDL cholesterol are not targeted for preventative therapies because they are not considered at risk for heart disease," said Ballantyne. "However, we found that even if patients have normal LDL levels, they are at increased risk for heart disease if they have high levels of either Lp-PLA2 or CRP, and at even greater risk if they have elevated values of both Lp-PLA2 and CRP. Based on these findings, this study is a valuable step in developing preventative strategies that may utilize blood tests for Lp-PLA2 and CRP to identify high risk patients."
Coronary heart disease affects more than 12.9 million Americans, and ranks as the leading cause of death in the United States. According to the American Heart Association, nearly half of all patients who experience coronary events, such as heart attacks, do not exhibit traditional risk factors such as smoking, obesity, high blood pressure or elevated LDL cholesterol.
"As the developers of the PLAC test, diaDexus is proud to supply Dr. Ballantyne and his team with the technology needed to conduct this critical research - research that may lead to the improved cardiovascular health of millions of people," said Patrick Plewman, chief executive officer of diaDexus.
About diaDexus
diaDexus, a privately held biotechnology company, based in South San Francisco, Calif., is focused on the discovery, development and commercialization of novel, patent-protected diagnostic and therapeutic products with high clinical value. diaDexus utilizes genomics and bioinformatics to identify numerous disease-associated molecular targets. More information about the company may be found at www.diaDexus.com.
Note to editors: Dr. Ballantyne is availavle for interviews. Slides, graphic and animation available.
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