Association between carotid artery function and structure in the Northern Manhattan Study

Abstract

Background and purpose: Carotid plaque (CP), carotid intima media thickness (cIMT), and stiffness (STIFF) are pre-clinical markers of atherosclerosis and predictors of cerebrovascular disease (CVD). We sought to investigate whether STIFF is a significant determinant of cIMT and CP, which may provide an insight into the mechanism by which STIFF adds to the risk of CVD. Methods: We analyzed 876 stroke-free subjects from the Northern Manhattan Study with available ultrasound measures. To obtain the associations with STIFF, we performed multivariable-adjusted regression, negative binomial regression (for CP number), and multinomial logistic regression (for plaque area). Results: The mean age was 64 ± 9 years; 63% women and 65% Caribbean Hispanics. The mean cIMT was 0.93 ± 0.9 mm, the mean diastolic diameter 6.24 ± 0.94 mm, and STIFF 8.6 ± 6.2 ln mmHg. Prevalence of CP was 57%, and the mean total plaque area was 22.6 ± 23.0 mm2. STIFF was positively associated with cIMT but not with CP. There was an association between diastolic diameter and thick plaque. For each millimeter increase in diastolic diameter, there was about a 20% increased risk of having thick plaque (vs. no plaque). In longitudinal analyses, each millimeter increase in diastolic diameter was associated with a 37% increased risk of incident plaque. Conclusion: Increased STIFF was associated with increased cIMT and carotid artery dilatation with greater plaque burden. Increased cIMT and plaque burden represent vascular remodeling likely resulting from the two different age-related mechanisms, one that includes diffuse wall thickening (cIMT) with STIFF and another that incorporates focal atherosclerosis (plaque) with luminal dilatation.