New Risk Factor for Heart Disease Discovered

A study has shown that an enzyme called phospholipase A2 (Lp-PLA2), an inflammation marker, is a strong risk factor for coronary heart disease (CHD), independent of other known risk factors such as low-density lipoprotein. The study, led by Chris J. Packard, D.Sc., University of Glasgow (UK), was published in the October 19 issue of The New England Journal of Medicine. A diagnostic test kit for Lp-PLA2 is under development.

The study involved blood samples collected during an earlier study called the West of Scotland Coronary Prevention Study (WOSCOPS). The researchers examined the cases of 580 men in WOSCOPS who had suffered adverse coronary events, such as heart attacks or bypass surgery. These were compared with 1,160 other men from the Scottish study who had not suffered a coronary event. All men were middle-aged and had above-normal cholesterol levels.

Examining five ranges, the study found a strong correlation between Lp-PLA2 and coronary events. The risk of an event was about two times greater in those subjects in the highest range than in subjects in the lowest range. Lp-PLA2 was shown to be a strong risk factor independent of low density lipoprotein (LDL) cholesterol and other markers of inflammation, such as C-reactive protein.

"Given the fact that 50% of the individuals with coronary artery disease have normal lipid levels, there is a clear need for novel risk factors. This study highlights the potential for Lp-PLA2 as a novel, independent risk factor,” said Patrick Plewman, president and CEO of diaDexus, Inc. (Santa Clara, CA, USA). The company has an exclusive license to Lp-PLA2 for diagnostic purposes, and developed the assay used in the study. diaDexus intends to commercialize the assay as a diagnostic test.