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A Warning Sign for Heart Disease

April 16, 2001 -- A test to gauge who has a greater risk for serious heart problems may be one step closer today thanks to the work of some Japanese researchers.

In a study published in the April 17 issue of Circulation: Journal of the American Heart Association, the researchersdetail a blood test they developed which can measure levels of a specific form of "bad cholesterol" responsible for causing problems from heart disease. Furthermore, they show that the more of this cholesterol a person has in their blood, the more they are at risk for serious heart problems.

This research may someday lead to more effective tests and better treatments for heart disease. However, more research is needed before these new findings will have a practical impact on patient care.

It's been known for years that in order for the bad cholesterol, or low density lipoprotein (LDL), to cause problems with heart disease it needs to be oxidized -- meaning oxygen gets added to it. However, it wasn't easily measured in the blood because it exists in such small quantities.

"This is the first study to demonstrate that levels of oxidized LDL in blood plasma relate directly to the severity of heart disease," co-author Makiko Ueda, MD, tells WebMD. "Our method of measuring oxidized LDL is superior to other methods, and we are now doing more research on this topic." Ueda is a professor of pathology at Osaka City University Medical School in Japan.

In this study, the researchers looked at levels of oxidized LDL in people with heart attacks, people with angina, and some with no heart problems. Their sophisticated test enabled them to identify tiny amounts of the oxidized form of LDL, which then allowed them to show that the levels of oxidized LDL circulating in the blood affected the severity of a person's heart diseases.

"This is an exciting study," Stephen Siegel, MD, tells WebMD. "It's not exactly surprising -- more that someone has finally been able to demonstrate something in humans that we thought was the case, based on theoretical and animal research." Siegel is an assistant clinical professor at New York University School of Medicine and a cardiologist at NYU Medical Center.

Many people picture heart disease as tiny fat globules gradually plugging up an artery, but that image is too simple, Siegel says. Over the past 10 years we've learned that during a heart attack the plaque lining the artery wall ruptures and releases chemicals that allow a clot to form, and this blood clot blocks the artery.

"We need to identify the reason the plaque ruptures, and that's where this research comes in," he says. "We know some people can have plaques and even severe blockages for years without going on to have a heart attack. What makes them different from the 40-year-olds who have a mild obstruction that ruptures, and go on to have a heart attack?"