Doctors rethink nature of plaques

SAN FRANCISCO, Sept. 25 (UPI) -- U.S. doctors say the untreated plaques causing unexpected heart attacks are not mild lesions as previously thought.

The plaques are made up of fat, cholesterol, calcium and other substances found in the blood. The plaques at high risk of causing an adverse cardiovascular event had large plaque burdens and/or small lumen areas -- clear space in the vessel.

These areas were invisible to the coronary angiogram but identifiable by intra-vessel ultra sound imaging, the researchers said.

The areas with the highest risk were those showing a necrotic core -- area of dead tissue -- but without a visible cap of fibrous tissue -- a thin cap fibroatheroma.

"As a result of the trial, we are closer to being able to predict -- and therefore prevent -- sudden, unexpected adverse cardiac events," Dr. Gregg Stone of Columbia University Hospital and the New York-Presbyterian Hospital/Columbia University Medical Center, the study's principal investigator, said in a statement

The findings of the multicenter study, which involved 700 acute coronary syndrome patients, were presented at the 21st annual Transcatheter Cardiovascular Therapeutics scientific symposium in San Francisco.