March 21st, 2012
04:18 PM ET
Most heart attacks hit without warning – when a blister plaque on the blood vessel wall ruptures. The resulting clot starves the heart of oxygen and nutrient-rich blood, causing a heart attack and possibly death.
Traditional diagnostic tools like treadmill stress tests only pick up major blockages in the blood vessels, but they don’t alert doctors to this type of impending catastrophe. That’s because the vast majority of heart attacks occur in people whose blood vessels are narrowed only slightly by cholesterol-laden plaque.
“We can’t detect these mild narrowings, which are almost exclusively responsible for heart attacks,” says Dr. Eric Topol, director of the Scripps Translational Science Institute in La Jolla, California.
But Topol and a team of researchers now think they’ve found a way to determine which patients are only days or weeks away from a heart attack.
Topol says they hope to have a simple blood test ready next year to flag patients in immediate danger of plaque dislodging and causing a heart attack. Doctors would know in minutes if patients were on the brink of an attack.
Initially, the test would be given to people who arrive in a hospital emergency department with chest pain but were not currently having a heart attack. The test would show if a heart attack is likely in the coming days, and the patient could be given aspirin and prescription medications to prevent clots, Topol says.
In the future, Topol says he envisions an implant the size of a grain of rice that would analyze circulating blood and send an alert if a heart attack was imminent.
The Scripps researchers’ findings were published Wednesday in the journal of Science Translational Medicine, published by the American Association for the Advancement of Science
Every year, the American Heart Association estimates 1.5 million Americans have heart attacks; 785,000 are suffering their first heart attack, usually with no warning. Slow narrowing of the blood vessels over time can result in chest pain, called angina, but these mature plaques are less likely to rupture, Topol says.
Traditional risk factors for heart attacks include inactivity, obesity, high blood pressure, cigarette smoking, poor diet, high cholesterol and diabetes. But figuring out who was at highest risk of an imminent heart attack hasn’t been possible.
In search of a precise marker, the Scripps team looked at 50 patients who arrived at the hospital with chest pains but whose subsequent tests showed they had not had a heart attack. Topol says these were patients who likely had clot that dissolved on its own.
The researchers found the endothelial cells of these patients looked very different from those of healthy individuals in a control group. For starters, four times as many endothelial cells were circulating in the blood of patients on the verge of a heart attack. The endothelial cells were also larger, misshapen and frequently contained many nuclei.
The National Institutes of Health and the American Reinvestment and Recovery Act, better known as the stimulus, provided funding for the research.
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