Abstract 6199: Relationship of Carotid Arterial Compliance and Thoracic Aorta Calcification: Multi-Ethnic Study of Atherosclerosis (MESA)
Decreased arterial compliance is one of the earliest manifestations of adverse structural and functional changes within the vessel wall. Prior studies have shown that indirect measures of arterial stiffness predict severity of atherosclerosis as well as subsequent cardiovascular events. Ultrasonography of the common carotid artery however enables a direct measurement of compliance and stiffness and may be a more sensitive marker of subclinical vascular disease. MESA is a longitudinal, population-based study of 6,814 men and women aged 45–84 without clinical cardiovascular disease at enrollment. Of these, 3,540 (62± 10 years, 47% males) individuals underwent arterial compliance assessment via calculation of the distensibility coefficient (DC, in 1/mmHg ×103), which uses carotid ultrasonographic measurements of cardiac cycle-dependent vessel size and upper arm measurements of blood pressure. All patients had their thoracic artery calcium (TAC) calculated using non-contrast cardiac CT. The cross-sectional association between decreasing quartiles of DC (4th quartile as reference group) and TAC was assessed by multivariable relative risk regression using a generalized linear model and binomial error distribution. The mean DC in the study population was 2.51± 1.11. Overall, 1,828 (28%) individuals had detectable TAC. A lower DC was observed among those with vs. without TAC (2.06± 0.90 vs. 2.69± 1.13, p<0.0001). The prevalence of TAC increased significantly across decreasing quartiles of DC (4th: 11%, 3rd: 21%, 2nd: 32%, 1st: 11%, p<0.0001). The table⇓ below demonstrates the adjusted relative risk for presence of TAC with decreasing quartiles of DC. Decreased arterial compliance measured by carotid ultrasonography is independently correlated with thoracic aortic atherosclerosis. Further studies are in progress to assess the prognostic value of this marker of subclinical atherosclerosis.