Someday doctors may be able to use a blood test to confirm within minutes, instead of hours, if a patient is having a heart attack, allowing more rapid treatment that could limit damage to heart muscle.
A study led by investigators from Massachusetts General Hospital (MGH) and the Broad Institute of Harvard and MIT reports that a new technique that measures hundreds of molecular markers in the blood can identify those released when cardiac tissue is injured by a lack of oxygen. The report will appear in the October Journal of Clinical Investigation and has received early online release.
"Right now there are no blood markers for reversible myocardial injury in clinical use, and the only available markers are not detectable until hours after the onset of tissue damage. Because our treatments for heart attacks are most effective in the first hours after symptoms occur, these newly identified markers could help us apply treatments sooner and help more patients," says the study's senior author Robert Gerszten, MD, of the MGH Division of Cardiology and Center for Immunology and Inflammatory Diseases.
Every metabolic activity in the body results in the production of metabolites, molecules released in often-minute quantities. A blood sample contains hundreds of these metabolites that could provide a chemical 'snapshot' of an individual's heath status. But the technology to assess metabolite levels is in the early stages, as is the understanding of their significance. For instance, how much metabolite levels normally vary between healthy individuals and factors that influence those variations is still unknown.
In the current study, the research team took advantage of a procedure that is, in essence, a planned heart attack. In a condition called hypertrophic cardiomyopathy, bloodflow out of the heart is obstructed by a massive thickening of the wall between the left and right sides. This tissue overgrowth can be treated with a technique called septal ablation - pioneered by Michael Fifer, MD, of MGH Cardiology - that destroys the excess tissue, a scenario that mimics the damage that happens to heart muscle when its blood supply is cut off. Taking blood samples before and after patients receive this procedure provides a unique window into metabolic changes that occur in response to the death of myocardial tissue, allowing study participants to act as their own controls.