Abstract 429: High-Risk Features of Carotid Atherosclerotic Disease Occur Bilaterally: A Cross-Sectional, High-Resolution MRI Investigation

Abstract

Background: The presence of intraplaque hemorrhage (IPH), large lipid rich necrotic core (LRNC), and fibrous cap rupture (FCR) in the carotid plaque as detected by magnetic resonance imaging (MRI) has been associated with future cerebrovascular events. This study sought to determine whether these high-risk features occur symmetrically in the carotid arteries. Methods: Multi-contrast MR images of both carotids from 119 patients with 50- 79 % stenosis in at least one carotid artery were reviewed. Images from each artery were interpreted independent from results of the contralateral artery. Images were reviewed for presence/absence of LRNC, IPH and FCR. The maximum size of LRNC relative to the wall (%LRNC) was also recorded. Results: Table 1 shows the significantly increased probability of having IPH and LRNC on the contralateral side when present on one side while FCR was nearly significant. In patients with LRNC present, there was a strong correlation in size of %LRNC between sides (Pearson’s r = 0.60, p<0.001). However, there was a significant difference in mean size of %LRNC between the two sides (30.0 vs. 12.8 %, p<0.001; paired t-test). Conclusion: These results provide compelling evidence that high-risk features of atherosclerotic disease are prone to develop bilaterally, although not concurrently, in patients with carotid disease. Presence of unstable features in one artery appears to herald the development of similar features in the contralateral artery which suggests that the pathophysiology of the high risk plaque is governed by systemic factors.