Study finds possible new culprit in heart disease

Wednesday, October 18th 2000, 12:00 am
By: News On 6

Researchers have pinpointed an enzyme in the blood that could one day join high cholesterol as another strong predictor of heart disease.

Several lifestyle factors, such as smoking and obesity, point to a heightened risk of heart disease. High levels of some blood substances, like the bad form of cholesterol, already help predict who will develop heart problems. However, researchers estimate that only half of the overall risk can be estimated from known factors.

If the new findings are confirmed, the enzyme, known as phospholipase A2, could take its place as a separate, strong predictor of a healthy person's risk of heart disease, researchers said.

``It would be very useful, because what we want to prevent is the all-important first heart attack,'' said molecular biochemist Colin MacPhee, one of the study's authors. ``Once you've had one, your risk is greater.''

Phospholipase A2 is still not fully understood. It appears to break down fat, may promote inflammation and possibly contributes to the buildup of clogging deposits inside blood vessels.

The study, which was directed at the Glasgow Royal Infirmary in Scotland, was published Thursday in The New England Journal of Medicine.

The researchers analyzed the enzyme in 580 men who had suffered serious heart trouble, mostly heart attacks. They were compared with 1,160 other men with no such history. The top fifth of the men with the highest enzyme levels had twice the risk of those who ranked in the bottom fifth.

Biochemist Chris Packard, who led the study, said the enzyme may provide ``a new focus for efforts to better identify and manage patients at risk of heart attack.''

The search for such warning signs is important because about 60 million Americans suffer from some kind of cardiovascular illness. It leads all diseases in killing about 950,000 a year.

Dr. Paul Ridker, a cardiologist at Brigham and Women's Hospital in Boston, said the findings, combined with the results of a second study in Thursday's journal, add to the evidence of the role of inflammation in heart disease.

The second study, carried out at the University of Uppsala in Sweden, shows that some known predictors of short-term risk for heart disease patients _ like the inflammatory C-reactive protein _ also signal a long-term risk of death from cardiac trouble.