Iron in coronary artery plaque ‘a marker of heart attack risk’

WASHINGTON - A new research has found that iron, derived from blood, is much more prevalent in the kind of plaque that is unstable and is more likely to promote a heart attack and possibly sudden death.

Researchers at Mayo Clinic have demonstrated through a variety of experiments that iron build-up may be suitable as a marker of risk for a future myocardial infarction (MI).

“We know that 70 percent of heart attacks are caused by unstable plaque, so what we really need for our patients is a way to identify the plaque that turns evil and puts them at jeopardy,” said cardiologist Birgit Kantor, study’s lead researcher.

“We think it is possible, based on these findings, to use iron as a natural marker for risk,” she said.

Mayo Clinic researchers believe that the amount of iron in the plaque can be seen as’readout’ of prior hemorrhagic, or bleeding, events that put a person at risk for plaque eruption.

To conduct the study, researchers used samples from a unique Mayo Clinic biobank of heart arteries collected over time from autopsies of 400 patients who died from a suspected heart attack. Small sections (1-1.5 inches) from the three main coronary arteries of each patient have been preserved.

Yu Liu, the study’s first author, applied a stain to the samples to detect iron content. She found iron content in the unstable plaque group was significantly higher than in the other groups. Iron was absent in normal arteries.

In a third step, the researchers scanned a subset of the artery segments using a benchtop micro-CT scanner, and created 3-D images to look for iron deposits in plaque. The CT could identify iron in plaque without the need for staining.

“There was a high correlation between the vulnerability of the plaque and the quantity of iron in it,” said Kantor.

The findings were presented at the American Heart Association’s Scientific Sessions 2010 in Chicago. (ANI)