scientists may be on the track to develop a gene-based diagnostic test to diagnose coronary artery disease, or CAD.

Working with , a private molecular diagnostics company based in California, the Duke team said a current trial could validate earlier work that has identified 14 genes linked to the disease.

"We have identified 14 genes in circulating blood cells that are exquisitely sensitive to the inflammatory changes that occur when plaque begins to accumulate in coronary arteries," said , the lead author on the study who is a member of the Duke Heart Center faculty.

"What’s really exciting is that the expression of these genes is also related to the degree of stenosis, or blockage of the arteries,” he added. “This means that a blood test based on these genes could tell us not only if someone has CAD, but also how bad the blockage in their arteries really is."

The initial findings of the study, which was funded by CardioDx, were published in the first issue of the journal “Circulation: Cardiovascular Genetics.”

The researchers hope to develop a test based on a blood sample that would diagnose CAD.

"We are committed to developing a test that will enable more informed therapeutic decisions by allowing cardiologists to fine-tune their approach to diagnosing CAD while minimizing unneeded interventions," said Steven Rosenberg, chief scientific officer at CardioDx.

CAD kills some 700,000 people a year in the U.S., according to the Centers for Disease Control. That total represents 29 percent of the nation’s annual death toll.

Current detection of CAD requires stress tests, cardiograms, imaging and other tests as well as procedures including catheterizations.

"A blood-based test to diagnose CAD would be less invasive and risky and would prevent patients from radiation exposure," Kraus told Duke University News Service. "Patients who receive a positive test result might be able to short-circuit additional preliminary evaluations and head directly to coronary catheterization, where blockages could be treated."

Preliminary research include tests and genome microarray analysis of samples from 41 patients at a heart center in Germany. Of those, 27 had undergone catheterizations.

The blood samples and genes were compared to blood taken from 215 catheterization patients at Duke.

Based on the samples and testing, the researchers identified 14 genes they said were “proportional” to the extent at which patients had developed stenosis.

"We need to stress that we are not talking about a cause and effect relationship here," Kraus said. "We do not know if theses genes cause CAD in any way or if their altered expression is in response to the disease. What we do know, however, is that their collective ‘signature’ is clearly associated with the presence of CAD."

The expanded trial was launched in 2007 and is being conducted at 28 sites in the U.S.

Geoffrey Ginsburg of the Duke faculty, who also participated in the writing of the study, is part owner of CardioDx.