Fat around the heart is more strongly related to coronary artery plaque than either body mass index or waist circumference – even among those without symptoms of atherosclerosis, according to a new study in the journal Radiology.
For the study, 183 individuals, generally overweight but without clinical cardiovascular disease, were recruited from the Baltimore and Chicago field centers of the Multi-Ethnic Study of Atherosclerosis. Participants included 89 women and 94 men with an average age of 61 years. Researchers used magnetic resonance imaging (MRI) to measure coronary artery eccentricity, or the ratio of maximal to minimal artery wall thickness, as a measure of early-stage atherosclerosis. The team also used computed tomography (CT) to determine pericardial fat volume.
“The individuals in this study had no symptoms and were otherwise healthy,” said lead author David Bluemke, MD, PhD, director of Radiology and Imaging Sciences at the National Institutes of Health Clinical Care. “They did not have significant coronary artery narrowing. Yet, despite this, they had coronary plaque that could be detected by MRI.”
While previous studies have looked at the relationship of pericardial fat to atherosclerosis in patients with severe coronary disease, this is the first study to determine the association of pericardial fat on coronary artery plaque burden in asymptomatic individuals, the authors said.
The results showed pericardial fat volume to correlate significantly with the degree of plaque eccentricity in both men and women. After adjustment for BMI, waist circumference, traditional risk factors, C-reactive protein level and coronary calcium content, the relationship between pericardial fat and plaque eccentricity remained significant in men, but not in women.
“The findings indicate yet another reason that obesity is bad for us,” Bluemke said. “It is particularly bad when the fat forms around the heart, since the heart fat appears to further promote coronary artery plaque.”