WEDNESDAY, March 21 (HealthDay News) -- A new blood test may be able to predict a heart attack before it actually happens, the test's developers claim.

Doctors traditionally rely on treadmill stress tests to predict heart attacks, which can tell if there is a blockage in the coronary arteries but not whether or when that blockage might rupture and cause a heart attack.

Enter the new blood test.

Individuals with high levels of misshapen circulating endothelial cells (CECs) coming from the lining of blood vessels may be at imminent risk for having a heart attack, the researchers report.

"We never had a way to predict a heart attack, but we are good at diagnosing it," said study author Dr. Eric Topol, of Scripps Translational Science Institute in San Diego. "This new test is the beginning of a very important advance, and is filling a major unmet need."

Topol has filed for a patent on the technology used to measure CECs, along with the companies that are developing it. He said he hopes the test will be available in the next 18 months.

The findings appear in the March 21 issue of the journal Science Translational Medicine.

The study included 50 heart attack patients and 44 healthy volunteers. Researchers used fluorescent images to show that CECs from heart attack patients look much different those seen in healthy individuals. According to the study, the levels of these blood cells seen in people at risk for heart attack may be more than 400 percent higher than in healthy people.

As to when the numbers of CECs start to rise to detectable levels, "the outer window is a couple of weeks, and we think it is about one week on average," Topol said. "Once we have cells in the blood, the heart attack is not going to occur in the next few minutes. We have at least a few days."

And therein lies the window of opportunity. "If we can prevent the blood clot, we prevent the heart attack," Topol said.

Topol noted that the test could be useful in emergency rooms, when people are admitted with chest pains but traditional tests come back normal.

However, two experts say it's too soon to tell whether this test could do better.

"This may be a novel biomarker for heart attack risk," said Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital, in New York City. But "the new test is not ready for prime time."

Unless and until more studies confirm the test's ability to predict heart attack, she said, "prevention really comes down to managing risk factors for heart attack." This includes eating a healthy diet, making sure blood pressure and cholesterol are where they should be, not smoking and exercising regularly.

Dr. Barry Kaplan, vice chairman of cardiology at North Shore University Hospital in Manhasset, N.Y., and Long Island Jewish Medical Center in New Hyde Park, N.Y, agreed that more study is needed to validate what role this new test can have in predicting heart attack.

"It may have potential to be predictive, but we do not know when these cells become abnormal in relation to when a heart attack occurs," he said. "All we have now is decreasing risks, particularly cigarette smoking and cholesterol levels. This is the best way to decrease the probability of a plaque rupture that will cause a heart attack."

More information

Learn more about heart attack risks at the U.S. National Heart, Lung, and Blood Institute.