title: High-risk plaque in the superficial femoral artery of people with peripheral artery disease: prevalence and associated clinical characteristics.
abstract: 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 1.5 T S platform. Twelve contiguous 2.5 mm 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.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov. Unique identifier: NCT00520312.
authors.affiliation: Department of Medicine, University of Chicago, Chicago, IL, USA. Electronic address: tpolonsky@medicine.bsd.uchicago.edu.
authors.forename: Tamar S
authors.initials: TS
authors.lastname: Polonsky
authors.affiliation: Department of Preventive Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: kiangliu@northwestern.edu.
authors.forename: Kiang
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Health Research and Policy, Stanford University School of Medicine, Palo Alto, CA, USA. Electronic address: lutian@stanford.edu.
authors.forename: Lu
authors.initials: L
authors.lastname: Tian
authors.affiliation: Department of Biomedical Engineering and Radiology, Northwestern University, Chicago, IL, USA. Electronic address: jcarr@northwestern.edu.
authors.forename: James
authors.initials: J
authors.lastname: Carr
authors.affiliation: Department of Biomedical Engineering and Radiology, Northwestern University, Chicago, IL, USA. Electronic address: t-carroll@northwestern.edu.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Carroll
authors.affiliation: Department of Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA. Electronic address: Jarett.Berry@UTSouthwestern.edu.
authors.forename: Jarett
authors.initials: J
authors.lastname: Berry
authors.affiliation: Department of Family and Preventive Medicine, University of California at San Diego, San Diego, CA, USA. Electronic address: mcriqui@ucsd.edu.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Criqui
authors.affiliation: Laboratory of Clinical Epidemiology, National Institute on Aging, Bethesda, MD, USA. Electronic address: FerrucciLu@grc.nia.nih.gov.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.affiliation: Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA. Electronic address: JGuralnik@epi.umaryland.edu.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.affiliation: Division of Vascular Surgery, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: mkibbe@nmh.org.
authors.forename: Melina R
authors.initials: MR
authors.lastname: Kibbe
authors.affiliation: Department of Radiology and Medicine, University of Virginia Health System, Charlottesville, VA, USA. Electronic address: ckramer@virginia.edu.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kramer
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA, USA. Electronic address: redwindowlfy@yahoo.com.cn.
authors.forename: Feiyu
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA, USA. Electronic address: xdx@uw.edu.
authors.forename: Dongxiang
authors.initials: D
authors.lastname: Xu
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA, USA. Electronic address: xihao.zhao@gmail.com.
authors.forename: Xihao
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA, USA. Electronic address: cyuan@u.washington.edu.
authors.forename: Chun
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Department of Preventive Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA; Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA. Electronic address: mdm608@northwestern.edu.
authors.forename: Mary M
authors.initials: MM
authors.lastname: McDermott
mesh_terms: D000368:Aged; D055109:Ankle Brachial Index; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D005263:Femoral Artery / Q000473:pathology*; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009991:Oscillometry; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000473:pathology*; D058226:Plaque, Atherosclerotic / Q000175:diagnosis* / Q000473:pathology*; D015995:Prevalence; D011446:Prospective Studies; D011897:Random Allocation; D012907:Smoking; D016896:Treatment Outcome; D016138:Walking
chemical_list: D008055:Lipids
keywords: Atherosclerosis; Magnetic resonance imaging; Peripheral vascular disease; Plaque