Researchers say they may have an explanation as to why African Americans are at an increased risk for heart attacks compared to Caucasians

The answer may be increased levels of non-calcified plaque which consists of buildups of soft deposits deep in the walls of the arteries that are not detected by some cardiac tests. Non-calcified plaque is more vulnerable to rupturing and causing a blood clot, which could lead to a heart attack or other cardiovascular event. "The African Americans and Caucasians we studied had approximately the same amount of plaque in their arteries, but different kinds of plaque," said John W. Nance Jr., M.D., researcher in the Department of Radiology and Radiological Sciences at MUSC. Calcium scoring revealed that calcified plaque was much more prevalent in the coronary arteries of Caucasian patients than in the African Americans (45% vs 26%). Compared with Caucasians, African American patients had a significantly higher prevalence of non-calcified plaque (64% vs 41%), and more of it. The median volume of non-calcified plaque among the African American patients was 2.2 milliliters (mL), compared with 1.4 mL among Caucasians. "This study confirms that the coronary artery disease pathways that lead to acute cardiovascular events are different for Caucasians and African Americans," explained U. Joseph Schoepf, M.D., professor of radiology and medicine and director of cardiovascular imaging at MUSC.