Carotid Artery Plaque and Progression of Coronary Artery Calcium: The Multi-Ethnic Study of Atherosclerosis

Background: Carotid and coronary atherosclerosis are associated with each other in imaging and autopsy studies. The aim of this study was to evaluate whether carotid artery plaque seen on carotid ultrasound can predict incident coronary artery calcification (CAC). Methods: Agatston calcium score measurements were repeated in 5,445 participants of the Multi-Ethnic Study of Atherosclerosis (MESA; mean age, 57.9 years; 62.9% women). Internal carotid artery lesions were graded as 0%, 1% to 24%, or >25% diameter narrowing, and intima-media thickness (IMT) was measured. Plaque was present for any stenosis >0%. CAC progression was evaluated with multivariate relative risk regression for CAC scores of 0 at baseline and with multivariate linear regression for CAC score >0, adjusting for cardiovascular risk factors, body mass index, ethnicity, and common carotid IMT. Results: CAC was positive at baseline in 2,708 of 5,445 participants (49.7%) and became positive in 458 of 2,837 (16.1%) at a mean interval of 2.4 years between repeat examinations. Plaque and internal carotid artery IMT were both strongly associated with the presence of CAC. After statistical adjustment, the presence of carotid artery plaque significantly predicted incident CAC with a relative risk of 1.37 (95% confidence interval, 1.12-1.67). Incident CAC was associated with internal carotid artery IMT, with a relative risk of 1.13 (95% confidence interval, 1.03-1.25) for each 1-mm increase. Progression of CAC was also significantly associated (P < .001) with plaque and internal carotid artery IMT. Conclusions: In individuals free of cardiovascular disease, subjective and quantitative measures of carotid artery plaques by ultrasound imaging are associated with CAC incidence and progression.