High-risk plaque in the superficial femoral artery of people with peripheral artery disease: Prevalence and associated clinical characteristics

Objective: We used magnetic resonance imaging (MRI) to study the prevalence and associated clinical characteristics of high-risk plaque (defined as presence of lipid-rich necrotic core [LRNC] and intraplaque hemorrhage) in the superficial femoral arteries (SFA) among people with peripheral artery disease (PAD). Background: The prevalence and clinical characteristics associated with high-risk plaque in the SFA are unknown. Methods: Three-hundred-three participants with PAD underwent MRI of the proximal SFA using a 1.5TS platform. Twelve contiguous 2.5mm cross-sectional images were obtained. Results: LRNC was present in 68 (22.4%) participants. Only one had intra-plaque hemorrhage. After adjusting for age and sex, smoking prevalence was higher among adults with LRNC than among those without LRNC (35.9% vs. 21.4%, p=0.02). Among participants with vs. without LRNC there were no differences in mean percent lumen area (31% vs. 33%, p=0.42), normalized mean wall area (0.71 vs. 0.70, p=0.67) or maximum wall area (0.96 vs. 0.92, p=0.54) in the SFA. Among participants with LRNC, cross-sectional images containing LRNC had a smaller percent lumen area (33%±1% vs. 39%±1%, p<0.001), greater normalized mean wall thickness (0.25±0.01 vs. 0.22±0.01, p<0.001), and greater normalized maximum wall thickness (0.41±0.01 vs. 0.31±0.01, p<0.001), compared to cross-sectional images without LRNC. Conclusions: Fewer than 25% of adults with PAD had high-risk plaque in the proximal SFA using MRI. Smoking was the only clinical characteristic associated with presence of LRNC. Further study is needed to determine the prognostic significance of LRNC in the SFA.