title: Impact of Fiber Structure on the Material Stability and Rupture Mechanisms of Coronary Atherosclerotic Plaques.
abstract: The rupture of an atherosclerotic plaque in the coronary circulation remains the main cause of heart attack. As a fiber-oriented structure, the fiber structure, in particular in the fibrous cap (FC), may affect both loading and material strength in the plaque. However, the role of fiber orientation and dispersion in plaque rupture is unclear. Local orientation and dispersion of fibers were calculated for the shoulder regions, mid FC, and regions with intimal thickening (IT) from histological images of 16 human coronary atherosclerotic lesions. Finite element analysis was performed to assess the effect of these properties on mechanical conditions. Fibers in shoulder regions had markedly reduced alignment (Median [interquartile range] 12.9° [6.6, 18.0], p < 0.05) compared with those in mid FC (6.1° [5.5, 9.0]) and IT regions (6.7° [5.1, 8.6]). Fiber dispersion was highest in shoulders (0.150 [0.121, 0.192]), intermediate in IT (0.119 [0.103, 0.144]), and lowest in mid FC regions (0.093 [0.081, 0.105], p < 0.05). When anisotropic properties were considered, stresses were significantly higher for the mid FC (p = 0.030) and IT regions (p = 0.002) and no difference was found for the shoulder or global regions. Shear (sliding) stress between fibers in each region and their proportion of maximum principal stress were: shoulder (25.8 kPa [17.1, 41.2], 12.4%), mid FC (13.9 kPa [5.8, 29.6], 13.8%), and IT (36.5 kPa [25.9, 47.3], 15.5%). Fiber structure within the FC has a marked effect on principal stresses, resulting in considerable shear stress between fibers. Fiber structure including orientation and dispersion may determine mechanical strength and thus rupture of atherosclerotic plaques.
authors.affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK.
authors.forename: Graeham R
authors.initials: GR
authors.lastname: Douglas
authors.affiliation: Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Brown
authors.affiliation: Department of Radiology, School of Clinical Medicine, University of Cambridge, Box 218, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
authors.affiliation: Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Bennett
authors.affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. mpfs@eng.cam.ac.uk.
authors.forename: Michael P F
authors.initials: MPF
authors.lastname: Sutcliffe
authors.affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. zt215@cam.ac.uk.|Department of Radiology, School of Clinical Medicine, University of Cambridge, Box 218, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. zt215@cam.ac.uk.
authors.forename: Zhongzhao
authors.identifier: 0000-0003-3973-6157
authors.initials: Z
authors.lastname: Teng
mesh_terms: D016880:Anisotropy; D001158:Arteries; D020342:Finite Element Analysis; D006801:Humans; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013314:Stress, Mechanical
keywords: Atherosclerosis; Coronary; Fiber; Rupture; Stress