(dailyRx News) It's long been noted that African-Americans are at an increased risk for heart attacks, but the reason remained unknown. Investigators have now discovered a potential reason for the higher heart risk.
Medical University of South Carolina in Charleston researchers found that blacks are at an added risk of heart attacks because they appear to have increased levels of non-calcified plaque.
Non-calcified plaque is a build up of soft deposits deep in the walls of arteries that is not detected by all cardiac tests. The type of plaque is more prone to rupture, which could cause a blood clot leading to a heart attack or another cardiovascular event.
U.S. Department of Health and Human Services statistics show that African American adults are more likely to be diagnosed with coronary heart disease and are at greater risk of death from heart disease than white adults. In 2007, black men were 30 percent more likely than white men to die from cardiovascular disease.
Dr. U. Joseph Schoepf, M.D., professor of radiology and medicine and director of cardiovascular imaging at Medical University of South Carolina in Charleston, said researchers have long sought the reason blacks are at a higher risk of heart disease, yet had less coronary artery calcium than Caucasians. He said the non-calcified plaque was the only explanation.
Calcium scoring with a CT scan is a common screening tool for patients at risk for heart disease to check calcified plaque that can lead to heart attacks, but this test cannot detect non-calcified plaque.
Investigators compared 301 patients who underwent both calcium scoring with CT and contrast-enhanced coronary CT angiography, which provides a more comprehensive picture of the arteries, including the presence of non-calcified and mixed plaques.
Half of the participants were black and the other half were white. About a third were male.
The calcium scoring showed that calcified plaque was much more prevalent in the coronary arteries of white patients than in the African Americans. It also revealed that compared with the white patients, many more black patients had non-calcified plaque -- 64 percent of black patients versus 41 percent of white participants.
Based on these results, researchers suggest coronary CT angiography should be used as a screening tool for African Americans.
The results were published online in the journal Radiology.