A blood test that can predict whether a person is at high risk of suffering from a heart attack has been developed by researchers at Scripps Translational Science Institute, and published in the journal Science Translational Medicine. The test can provide the doctor and patient with this vital information up to two weeks before an acute myocardial infarction (heart attack) is likely to occur.
Team leader, cardiologist Eric Topol, explains that if this test is demonstrated to be reliable after further studies, doctors will be better equipped and informed to intervene with patients at very high risk of an imminent heart attack, and thus prevent the attack and the subsequent damage it can cause.
The authors explain that acute myocardial infarction is currently highly unpredictable, despite recent progress in the diagnoses and treatments of coronary artery disease. They add that doctors desperately need a clinical measurement that can predict an impending heart attack.
In this study, a blood test was devised that identifies specific cells that flake off when the blood vessel walls weaken - they are called CECs (circulating endothelial cells), and signal the initial stages of acute myocardial infarction.
Cardiologists believe that a heart attack typically commences days before the formation of a clot (which blocks blood flow to the heart). During the initial stages of a heart attack, the walls of the blood vessel weaken, they become eroded, attracting inflammatory cells, which in turn harm and damage the endothelial cells that line the inside of blood vessels. Endothelial cells are those that form the cellular lining of a tissue. Severe inflammation causes the CECs to mutate, they clump together, break off and get into the bloodstream.
The study involved 94 participants, 50 of them had had a heart attack while the other 44 had not (healthy controls). CEC blood levels among those who had had a heart attack were over four times higher compared to those in the healthy control group.
Not only were CEC blood levels much higher among the heart attack patients, but also their CECs had changed; they had either become larger, misshapen, and/or many had multiple nuclei.
Diagram showing where the endothelial cells are, lining the walls of blood vessels
"For the first time, we can isolate these cells through techniques that were not available in 1999. They are like a window into the process that underlies an imminent heart attack."
Heart disease kills nearly 600,000 people in the USA each year - it is the leading cause of death in the country. People commonly come into emergency rooms suffering from chest pains, undergo diagnostic tests that reveal nothing unusual, are sent home, and suffer a heart attack with days. In a considerable number of cases, CECs sloughing off the interior wall of a blood vessel become involved in a series of events that results in a blood clot.
"It is the clot that cuts off the blood supply and serves as the proximate cause of a heart attack. Eventually, a plaque ruptures and a blood clot develops."
Written by Christian Nordqvist