Abstract 5030: Sex Differences of Carotid Atherosclerotic Plaque: In vivo 3T MRI Study

Abstract

Background: Carotid endarterectomy (CEA) to prevent stroke is less beneficial for women compared to men in asymptomatic patients. Sex differences in plaque characteristics may help explain why women receive less benefit from CEA. Numerous plaque features are associated with increased stroke risk such as thin/ruptured fibrous cap, larger lipid-rich/necrotic core (LRNC) and hemorrhage. We tested the hypothesis that within an asymptomatic carotid stenosis population, men have more of these high-risk carotid plaque features than women as detected by in vivo 3T MRI. Methods: One hundred twenty consecutive patients (men, 64, women, 56, age 45– 86) with >=50% asymptomatic carotid stenosis measured by duplex ultrasound were included. Two independent and blinded reviewers interpreted multi-contrast MR images of the more stenotic carotid. Presence of thin/ruptured fibrous cap and plaque components (LRNC, hemorrhage and calcium), and % component volume, if present, were documented. Multivariate logistic and linear regression analyses were used to quantify the association between sex and individual plaque characteristics adjusting for other potential confounders: age, statin use, smoking, history of hyperlipidemia, hypertension, coronary artery disease and diabetes. Results: The prevalence of plaque features and % volume components in men versus women were, respectively: thin/ruptured fibrous cap (47% vs 20%, p<0.01), LRNC (72% vs 48%, p=0.01), hemorrhage (31% vs 17%, p=0.11) and calcium (84% vs 89%, p=0.45); mean % volume of LRNC (5.7% vs 2.4%, p<0.01), hemorrhage (2.2% vs 0.3%, p=0.03) and calcium (4.6% vs 4.1%, p=0.58). Only statin use was found to be a significant confounder and included in the multivariate models. The adjusted odds ratio (aOR) were significantly greater for men (vs women) for presence of thin/ruptured fibrous cap (aOR, 3.5, 95%CI= 1.5, 8.0), and LRNC (aOR 3.6, 95%CI= 1.6, 8.1). Plaque volumes were also significantly larger in men for % LRNC (3.7%, 95%CI= 1.6, 5.7%), and % hemorrhage volume (1.9%, 95% CI=0.5, 3.2%). Conclusion: In patients with asymptomatic >=50% carotid stenosis, men tended to have higher-risk plaque features than women. These findings indicate a possible reason for why CEA is less effective in asymptomatic women. This research has received full or partial funding support from the American Heart Association, Midwest Affiliate (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota & Wisconsin).