Thoracic Aortic Distensibility and Thoracic Aortic Calcium (from the Multi-Ethnic Study of Atherosclerosis [MESA])

Decreased arterial distensibility is an early manifestation of adverse structural and functional changes within the vessel wall. Its correlation with thoracic aortic calcium (TAC), a marker of atherosclerosis, has not been well demonstrated. We tested the hypothesis that decreasing aortic compliance and increasing arterial stiffness would be independently associated with increased TAC. We included 3,540 subjects (61 ± 10 years, 46% men) from the Multi-ethnic Study of Atherosclerosis who had undergone an aortic distensibility (AD) assessment using magnetic resonance imaging. TAC was calculated using a modified Agatston algorithm on noncontrast cardiac computed tomographic scans. Multivariate regression models were calculated for the presence of TAC. Overall, 861 subjects (24%) had detectable TAC. Lower AD was observed among those with versus without TAC (2.02 ± 1.34 vs 1.28 ± 0.74, p <0.0001). The prevalence of TAC increased significantly across decreasing quartiles of AD (7%, 17%, 31%, and 42%, p <0.0001). Using multivariate analysis, TAC was independently associated with AD after adjusting for age, gender, ethnicity, and other covariates. In conclusion, our analysis has demonstrated that increased arterial stiffness is associated with increased TAC, independent of ethnicity and other atherosclerotic risk factors.