The presence of coronary artery calcium (CAC) on the CT scans of middle-aged individuals, especially African Americans, was associated with an increased risk of structural heart abnormalities and future heart failure in a new study, published online June 14 in Circulation: Cardiovascular Imaging.
Over the past several years, multiple studies have confirmed the association between high CAC scores and cardiovascular disease. Recognizing this research, the American College of Cardiology (ACC) and American Heart Association (AHA) recently published a new guideline recommending CT CAC testing for individuals at risk of developing atherosclerotic heart disease.
Further adding to this work, researchers from the U.S. and Brazil tracked the cardiovascular health of 2,449 individuals as part of the Coronary Artery Risk Development in Young Adults (CARDIA) trial. The study participants were between 18 and 30 years old; they underwent a baseline CT CAC exam followed by subsequent CT CAC testing at 15 years and 25 years after the initial exam. Approximately half of them were African Americans, and 57% were women.
The researchers focused their study specifically on "early adulthood to middle-age because this is a window in which we can see abnormalities that might not be causing symptoms but could later increase the risk of heart problems," co-author Dr. Henrique Moreira, PhD, from the University of São Paulo, said in a statement.
After analyzing the data, Moreira and colleagues found that individuals with positive CT CAC exams were more likely to have structural abnormalities in their heart's left ventricle -- a risk factor for heart failure -- compared with those who had a negative CT CAC exam. CT CAC scores exceeding 0, for example, were associated with a 12% increase in left ventricular mass index and a 9% increase in left ventricular end-diastolic volume.
|Association between CT CAC score and heart structure and function|
|CT CAC = 0||CT CAC score > 0|
|Left ventricular mass index (g/m2)||83||93|
|Left ventricular end-diastolic volume (mL)||108||118|
These structural abnormalities were particularly pronounced in African Americans, who had four times the increase in left ventricular mass for every single-digit increase in CT CAC score, compared with the cohort of white patients. Furthermore, the researchers identified a statistically significant association between an increase in CT CAC score between year 15 and year 25 and an increase in left ventricular mass -- only in African Americans.
"Racial differences in our findings may be due to genetic factors or perhaps greater exposure to cardiovascular risk factors that usually appear earlier in blacks," Moreira said. "We need more research to examine the link between coronary artery calcium and heart health."
"The results of this study are important as they highlight that presence of CAC and higher CAC scores may also be associated with echocardiographic markers of subclinical left ventricular systolic and diastolic dysfunction. ... [The results also] highlight the importance of primordial prevention and risk factor modification in early adulthood," Dr. Salim Virani, from Baylor College of Medicine in Houston, said in response to the study.