Roughly two and a half million Americans suffer a heart attack or a stroke each year. About 20% of these - half a million people - die in the aftermath. The proximate cause for both heart attack and stroke is a blood clot in the wrong place - a blood clot that could be prevented or minimized by anti-clot therapy if physicians knew that an attack or stroke was expected shortly. Recent findings from a research study led by Scripps Translational Science Institute (STSI) has identified a new blood test which has the promise of predicting heart attack or stroke weeks prior to their occurrence.

The STSI study studied endothelial cells circulating in the blood stream of heart attack patients and healthy control subjects. These cells, which line the surface of blood vessels, appeared normal when sampled from healthy subjects. However, they found that circulating endothelial cells in blood samples from heart attack patients were highly abnormal - enlarged, misshapen, and possessing multiple nuclei.

Normal circulating endothelial cells from a healthy subject (left) and abnormal circulating endothelial cells from a patient having a heart attack (right) (Image: Scripps Research Institute)

Heart attack and stroke generally begin with the rupture of pre-existing atheromas - accumulations of macrophage cells, lipids, calcium, and fibrous connective tissue that collect within artery walls. It now appears that the early stages of such ruptures produces abnormal endothelial cells which are swept away into the circulating blood. Circulating endothelial cells are therefore promising biomarkers for prediction of acute ongoing arterial plaque rupture - an event which often results in heart attack, stroke, or other circulatory problems.

“The ability to diagnose an imminent heart attack has long been considered the holy grail of cardiovascular medicine,” said Dr. Eric Topol, one of the study’s principal investigators and director of STSI. “This has been a tremendous collaboration of two institutions on the research side, three health care systems in San Diego, and a life science industry leader, which has resulted in an important discovery that may help to change the future of cardiovascular medicine.”

It is hoped that the validity and predictive ability of the new test will be elucidated in the next year or two, and that it will become part of the arsenal of cardiovascular medicine.

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