Fall 2013

Researcher seeks to assess heart attack risk

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Amber Doiron says it's hard to tell who's walking around with plaques that are stable and who has plaques that may cause a heart attack.

A Binghamton University researcher hopes to give doctors a more accurate way of determining a patient’s risk of heart attack or stroke.

Amber Doiron, assistant professor of bioengineering, says current methods of assessing atherosclerosis — or hardening of the arteries — are not very accurate. The disease occurs when fat, cholesterol and other particles form hard structures called plaques in the walls of arteries.

“Doctors use factors like blood pressure and cholesterol level to get an idea of a patient’s risk. Then they use plaque size as a general measure of whether a person has the disease. But there’s a fairly poor correlation between plaque size and heart attack or stroke,” she says.

Doiron and a Temple University colleague recently received a two-year, $418,000 grant from the National Institute of Biomedical Imaging and Bioengineering to try to help physicians identify which plaques are cause for concern. The researchers will use a combination of polymers and superparamagnetic iron-oxide nanoparticles for the study. The nanoparticle is sensitive to oxidative stress, which occurs in atherosclerosis and has been linked to patients who have a higher prevalence of heart attack and stroke. Using an MRI scan, the researchers will be able to see how active the nanoparticle is, which will indicate whether the plaque is stable.

“A stroke or a heart attack doesn’t necessarily come when a plaque fully blocks the flow of blood through an artery,” Doiron explains. “What happens is the plaque ruptures and the gunk that underlies the plaque is exposed to blood and a clot forms. The clot builds quickly and can grow until it blocks flow, or it can dislodge and block flow somewhere else. Most heart attacks do not occur from a full blockage of plaque. It happens because the plaque bursts. That’s why size isn’t necessarily indicative of how dangerous a plaque is.”

The discovery of a molecule or a cell type that indicates which plaques are safe and which ones are dangerous would be a huge breakthrough, Doiron says.

–Rachel Coker