Abstract 18848: Carotid Artery Remodeling is Segment Specific: An in Vivo Study by Cardiovascular Magnetic Resonance Imaging

Abstract

Introduction: Coronary atherosclerosis can be accompanied by coincident change in lumen and total vessel area, described as arterial remodeling. Early-stage atherosclerosis is believed to be associated with enlarged outer wall and preserved lumen (outward remodeling). However, direct in vivo evidence in the carotid artery is scarce. Magnetic resonance imaging provides a non-invasive means to characterize remodeling patterns in the carotid arterial wall. Hypothesis: We tested the hypothesis that carotid arteries exhibit expansive remodeling in a large cohort of asymptomatic subjects with multiple cardiovascular risk factors. We further examined whether remodeling is carotid segment specific. Methods: From the BioImage Study (NCT00738725), 525 subjects were evaluated with magnetic resonance imaging. Axial images of bilateral carotid arteries were acquired and categorized into common carotid artery (CCA), carotid bulb, and internal carotid artery (ICA) segments based on their distance to the flow divider. Lumen area (LA), total vessel area (TVA), and mean wall thickness (MWT) were measured on all slices and averaged for each CCA, carotid bulb, and ICA segments per subject. General linear models were used to examine cross-sectional associations of MWT with LA and TVA after adjustment for age, sex and body surface area. The regression slopes are presented as the cross-sectional area change per 1 mm MWT increase and were interpreted as indicators of the remodeling pattern. Results: A total of 489 subjects (mean age: 68 years; 49% female) with sufficient image quality were enrolled in this study. In the CCA, both TVA (Slope: 44.6 mm2, p<0.001) and LA (Slope: 11.9 mm2, p=0.009) tended to be larger with increased MWT, suggesting outward remodeling. In the ICA, TVA also increased with MWT (Slope: 17.0 mm2, p<0.001), while the LA tended to decrease (Slope: -6.8 mm2, p=0.07). In contrast, the TVA changed less in the carotid bulb with MWT (Slope: -8.2 mm2, p=0.29) while the LA distinctly decreased with increasing MWT (Slope: -35 mm2, p<0.001), consistent with inward remodeling. Conclusions: In this asymptomatic cohort with multiple risk factors, carotid artery atherosclerosis is accompanied by arterial remodeling which appears to be segment specific.