Sex Differences in Plaque Composition and Morphology Among Symptomatic Patients With Mild-to-Moderate Carotid Artery Stenosis

BACKGROUND AND PURPOSE: Incidence of ischemic stroke differs between men and women, with substantially higher rates in men. The underlying mechanism of this difference remains poorly understood but may be because of differences in carotid atherosclerosis. Using an in-depth imaging-based approach, we investigated differences between carotid plaque composition and morphology in male and female patients with stroke, taking into account differences in total plaque burden. Additionally, we investigated all possible within-artery combinations of plaque characteristics to explore differences between various plaque phenotypes. METHODS: We included 156 men and 68 women from the PARISK (Plaque At Risk) study, a prospective cohort study of patients with recent ischemic cerebrovascular symptoms and <70% ipsilateral carotid stenosis. Plaque characteristics (intraplaque hemorrhage [IPH], lipid-rich necrotic core [LRNC], calcifications, thin-or-ruptured fibrous cap, ulcerations, total plaque volume) were assessed with magnetic resonance imaging and multidetector-row computed tomography angiography. We used multivariable logistic and linear regression analyses to assess sex differences in plaque characteristics. RESULTS: We found significant difference in total plaque volume between men and women (β=22.9 mm(3) [95% CI, 15.4–30.5]; mean volume in men 1399±425 mm(3), in women 1011±242 mm(3)). Additionally, men were more likely to have IPH (odds ratio [OR]=2.8 [95% CI, 1.3–6.3]; IPH proportion in men 49%, in women 16%) and LRNC (OR=2.4 [95% CI, 1.2–4.7]; LRNC proportion in men 73%, in women 41%) even after adjustment for total plaque volume. We found no sex-specific differences in plaque volume-corrected volumes of IPH, LRNC, and calcifications. In terms of coexistence of plaque characteristics, we found that men had more often a plaque with coexistence of calcifications, LRNC, and IPH (OR=2.7 [95% CI, 1.2–7.0]), with coexistence of thin-or-ruptured fibrous cap/ulcerations, LRNC, and IPH (OR=2.4 [95% CI, 1.1–5.9]), and with coexistence of all plaque characteristics (OR=3.0 [95% CI, 1.2–8.6]). CONCLUSIONS: In symptomatic patients with mild-to-moderate carotid stenosis, men are more likely to have a high-risk carotid plaque with IPH and LRNC than women, regardless of total plaque burden. Men also have more often a plaque with multiple vulnerable plaque components, which could comprise an even higher stroke risk. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01208025.