Incident stroke is associated with common carotid artery diameter and not common carotid artery intima-media thickness.

BACKGROUND AND PURPOSE: The common carotid artery interadventitial diameter is measured on ultrasound images as the distance between the media-adventitia interfaces of the near and far walls. It is associated with common carotid intima-media thickness (IMT) and left ventricular mass and might therefore also have an association with incident stroke. METHODS: We studied 6255 individuals free of coronary heart disease and stroke at baseline with mean age of 62.2 years (47.3% men), members of a multiethnic community-based cohort of whites, blacks, Hispanics, and Chinese. Ischemic stroke events were centrally adjudicated. Common carotid artery interadventitial diameter and IMT were measured. Cases with incident atrial fibrillation (n=385) were excluded. Multivariable Cox proportional hazards models were generated with time to ischemic event as outcome, adjusting for risk factors. RESULTS: There were 115 first-time ischemic strokes at 7.8 years of follow-up. Common carotid artery interadventitial diameter was a significant predictor of ischemic stroke (hazard ratio, 1.86; 95% confidence interval, 1.59-2.17 per millimeter) and remained so after adjustment for risk factors and common carotid IMT with a hazard ratio of 1.52/mm (95% confidence interval, 1.22-1.88). Common carotid IMT was not an independent predictor after adjustment (hazard ratio, 0.14; 95% confidence interval, 0.14-1.19). CONCLUSIONS: Although common carotid IMT is not associated with stroke, interadventitial diameter of the common carotid artery is independently associated with first-time incident ischemic stroke even after adjusting for IMT. Our hypothesis that this is in part attributable to the effects of exposure to blood pressure needs confirmation by other studies. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00063440.

Concentration of Smaller High-Density Lipoprotein Particle (HDL-P) Is Inversely Correlated With Carotid Intima Media Thickening After Confounder Adjustment: The Multi Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: Recent studies have failed to establish a causal relationship between high-density lipoprotein cholesterol levels (HDL-C) and cardiovascular disease (CVD), shifting focus to other HDL measures. We previously reported that smaller/denser HDL levels are protective against cerebrovascular disease. This study sought to determine which of small+medium HDL particle concentration (HDL-P) or large HDL-P was more strongly associated with carotid intima-media thickening (cIMT) in an ethnically diverse cohort. METHODS AND RESULTS: In cross-sectional analyses of participants from the Multi Ethnic Study of Atherosclerosis (MESA), we evaluated the associations of nuclear magnetic resonance spectroscopy-measured small+medium versus large HDL-P with cIMT measured in the common and internal carotid arteries, through linear regression. After adjustment for CVD confounders, low-density lipoprotein cholesterol (LDL-C), HDL-C, and small+medium HDL-P remained significantly and inversely associated with common (coefficient=-1.46 µm; P=0.00037; n=6512) and internal cIMT (coefficient=-3.82 µm; P=0.0051; n=6418) after Bonferroni correction for 4 independent tests (threshold for significance=0.0125; α=0.05/4). Large HDL-P was significantly and inversely associated with both cIMT outcomes before HDL-C adjustment; however, after adjustment for HDL-C, the association of large HDL-P with both common (coefficient=1.55 µm; P=0.30; n=6512) and internal cIMT (coefficient=4.84 µm; P=0.33; n=6418) was attenuated. In a separate sample of 126 men, small/medium HDL-P was more strongly correlated with paraoxonase 1 activity (rp=0.32; P=0.00023) as compared to both total HDL-P (rp=0.27; P=0.0024) and large HDL-P (rp=0.02; P=0.41) measures. CONCLUSIONS: Small+medium HDL-P is significantly and inversely correlated with cIMT measurements. Correlation of small+medium HDL-P with cardioprotective paraoxonase 1 activity may reflect a functional aspect of HDL responsible for this finding.