ABSTRACT NUMBER: ESOC2026A1620 ETHNIC VARIATIONS IN CAROTID ARTERY CHARACTERISTICS AND PLAQUE FEATURES UNDERLYING DIFFERENTIAL CARDIOVASCULAR RISK: EVIDENCE FROM THE MESA COHORT

Abstract Background and aims Racial and ethnic differences in vascular remodeling, arterial stiffness, and plaque composition may underlie disparities in cardiovascular risk. Although carotid imaging captures these features in detail, whether their associations with major adverse cardiovascular events (MACE) differ across racial and ethnic groups remains incompletely understood. Methods We analyzed 4,716 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). Carotid ultrasound assessed wall area, intima-media thickness (IMT), remodeling index, normalized wall index, and Young’s modulus, while carotid MRI evaluated lipid core, calcium, fibrous cap thickness, and ulceration in a subset. Cox models estimated adjusted hazard ratios (HRs) for total and specific MACE over a median 10-year follow-up. Results Participants were White (40.8%), African American (26.5%), Hispanic (21.2%), and Chinese American (11.5%). African American participants had higher wall area, IMT, normalized wall index, and stiffness than other groups (all p<0.01). Total MACE occurred in 25.3% of Whites, 21.0% of African Americans, 26.0% of Hispanics, and 17.8% of Chinese Americans (p=0.02). In Hispanics, higher CCA wall area (adjHR 1.24, 95% CI 1.09–1.41), IMT (1.21, 1.03–1.42), remodeling index (1.21, 1.03–1.41), and Young’s modulus (1.21, 1.03–1.41) were associated with total MACE. IMT predicted myocardial infarction in White participants and Hispanics. Fibrous cap thinning predicted myocardial infarction and cardiovascular death in Hispanics, while lipid core presence predicted cardiovascular death in African Americans. Conclusions Carotid plaque burden and plaque features are independently associated with cardiovascular outcomes, with meaningful variation by ethnicity. Incorporating detailed carotid imaging may improve personalized cardiovascular risk assessment and prevention in diverse populations. Conflict of interest All authors: nothing to disclose