Common carotid artery intima-media thickness progression as a predictor of stroke in multi-ethnic study of atherosclerosis.

Background and Purpose: Carotid artery intima-media thickness (IMT) is a marker of cardiovascular disease associated with incident stroke. We studied whether IMT rate of change is associated with stroke.
Methods: We studied 5028 participants of the Multi-Ethnic Study of Atherosclerosis (MESA) comprising white, Chinese, Hispanic, and black participants free of cardiovascular disease. In this MESA IMT progression study, IMT rate of change (mm/year) was the difference in right common carotid artery far wall IMT (mm) divided by the interval between 2 ultrasound examinations (median interval, 32 months). Common carotid artery IMT was measured in a region free of plaque. Cardiovascular risk factors and baseline IMT were determined when IMT rate of change was measured. Multivariable Cox proportional hazards models generated hazard risk ratios (HR) with cardiovascular risk factors, ethnicity, and education level/income as predictors.
Results: There were 42 first-time strokes seen during a mean follow-up of 3.22 years (median, 3.0 years). Average age was 64.2 years, with 48% males. In multivariable models, age (HR, 1.05 per year), systolic blood pressure (HR, 1.02 per mm Hg), lower high-density lipoprotein cholesterol levels (HR, 0.96 per mg/dL), and IMT rate of change (HR, 1.23 per 0.05 mm/year; 95% confidence limit, 1.02-1.48) were significantly associated with incident stroke. The upper quartile of IMT rate of change had HR of 2.18 (95% confidence limit, 1.07-4.46) compared to the lower 3 quartiles combined.
Conclusions: Common carotid artery IMT progression is associated with incident stroke in this cohort free of prevalent cardiovascular disease and atrial fibrillation at baseline.