Blood Test May Give Early Warning on Heart Attack, Study Finds

A simple blood test may be able to tell patients if they’re in imminent danger of having a heart attack, a new study suggests.

Researchers compared blood samples of 50 heart attack patients with 44 healthy volunteers, and found a much higher level of abnormal circulating endothelial cells, or CECs, according to the study, published today by the journal Science Translational Medicine. Still, more study is needed before doctors can say with confidence that these abnormal cells are present before a heart attack occurs, said Barry Kaplan, vice chairman of cardiology for North Shore University Hospital in Manhasset, New York, who wasn’t involved in the study.

Endothelial cells line blood vessels and control the ability of arteries and veins to widen and prevent clots. The heart attack patients in the study had, on average, fivefold more abnormally shaped versions of these cells, with multiple nuclei, circulating in their blood than the healthy patients.

The discovery may tell doctors if someone has a crack or plaque rupture in an artery, which can lead to clot formation and heart attack, said Eric Topol, the study’s principal investigator and director of Scripps Translational Science Institute.

“Heart attacks only occur when this blood clot forms, and cuts off the blood supply,” Topol said in a telephone interview. “What this is about is catching it earlier than when the blood clot forms.”

Timing Critical

Heart disease is the leading cause of death in the U.S., and more than 1 million Americans have a heart attack every year, according to the U.S. Centers for Disease Control.

People often head to the hospital when they feel chest pain or pressure, only to be sent home when doctors can’t detect a problem with tests such as electrocardiograms, which measure irregular heart beats and heart damage, Topol said.

If the findings can be validated, a blood test that can take advantage of the discovery may be in use in hospitals as early as a year later, he said.

Using this information as a predictor of imminent heart attack may be premature, Kaplan said.

“They’ve identified that these abnormal circulating endothelial cells are present at the time of plaque rupture -- the question is how far before plaque rupture are these cells abnormal?” Kaplan said in a phone interview. “We don’t know the answer to that based on this study.”

Current tests can only determine if a patient has a severely blocked artery, or already has damage to the heart muscle. Others with mild or moderate blockages often go undiagnosed. As a cardiologist, Topol has had patients pass stress tests only to have a heart attack weeks later.

Difficult Challenge

“It’s one of the most discouraging things you can have happen as a cardiologist,” he said. “I’ve learned from this -- it’s important to inform patients that you can still have a crack in your artery anytime -- we haven’t had a way to detect that. Hopefully now we do.”

Further into the future, patients at risk could have a nanosensor implanted in a vein to detect the abnormal cells and then send an alert to a device.

“They would get a ringtone on their phone, saying you’re going to be having a heart attack in the next week or two,” Topol said.

To contact the reporter on this story: Ryan Flinn in San Francisco at rflinn@bloomberg.net

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net

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