title: Material properties of components in human carotid atherosclerotic plaques: a uniaxial extension study.
abstract: Computational modelling to calculate the mechanical loading within atherosclerotic plaques has been shown to be complementary to defining anatomical plaque features in determining plaque vulnerability. However, its application has been partially impeded by the lack of comprehensive knowledge about the mechanical properties of various tissues within the plaque. Twenty-one human carotid plaques were collected from endarterectomy. The plaque was cut into rings, and different type of atherosclerotic tissues, including media, fibrous cap (FC), lipid and intraplaque haemorrhage/thrombus (IPH/T) was dissected for uniaxial extension testing. In total, 65 media strips from 17 samples, 59 FC strips from 14 samples, 38 lipid strips from 11 samples, and 21 IPH/T strips from 11 samples were tested successfully. A modified Mooney-Rivlin strain energy density function was used to characterize the stretch-stress relationship. The stiffnesses of media and FC are comparable, as are lipid and IPH/T. However, both media and FC are stiffer than either lipid or IPH/T. The median values of incremental Young's modulus of media, FC, lipid and IPH/T at λ=1 are 290.1, 244.5, 104.4, 52.9, respectively; they increase to 1019.5, 817.4, 220.7 and 176.9 at λ=1.1; and 4302.7, 3335.0, 533.4 and 268.8 at λ=1.15 (unit, kPa; λ, stretch ratio). The material constants of each tissue type are suggested to be: media, c1=0.138kPa, D1=3.833kPa and D2=18.803; FC, c1=0.186kPa, D1=5.769kPa and D2=18.219; lipid, c1=0.046kPa, D1=4.885kPa and D2=5.426; and IPH/T, c1=0.212kPa, D1=4.260kPa and D2=5.312. It is concluded that all soft atherosclerotic tissues are non-linear, and both media and FC are stiffer than either lipid or IPH/T.
authors.affiliation: Department of Radiology, University of Cambridge, School of Clinical Medicine, Box 218 Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK; Department of Engineering, University of Cambridge, UK. Electronic address: zt215@cam.ac.uk.
authors.forename: Zhongzhao
authors.initials: Z
authors.lastname: Teng
authors.affiliation: Department of Vascular Surgery, Changhai Hospital, Shanghai, People's Republic of China; Department of Radiology, University of Cambridge, School of Clinical Medicine, Box 218 Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK.
authors.forename: Yongxue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiology, University of Cambridge, School of Clinical Medicine, Box 218 Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Vascular Surgery, Changhai Hospital, Shanghai, People's Republic of China.
authors.forename: Jiaxuan
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Radiology, University of Cambridge, School of Clinical Medicine, Box 218 Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Department of Vascular Surgery, Changhai Hospital, Shanghai, People's Republic of China.
authors.forename: Qingsheng
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Department of Engineering, University of Cambridge, UK.
authors.forename: Michael P F
authors.initials: MPF
authors.lastname: Sutcliffe
authors.affiliation: Division of Cardiovascular Medicine, University of Cambridge, UK.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Brown
authors.affiliation: Department of Vascular Surgery, Changhai Hospital, Shanghai, People's Republic of China.
authors.forename: Zaiping
authors.initials: Z
authors.lastname: Jing
authors.affiliation: Department of Radiology, University of Cambridge, School of Clinical Medicine, Box 218 Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
mesh_terms: D002339:Carotid Arteries / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000503:physiopathology*; D003198:Computer Simulation; D055119:Elastic Modulus; D006801:Humans; D066298:In Vitro Techniques; D008955:Models, Cardiovascular; D033081:Shear Strength; D013314:Stress, Mechanical; D013718:Tensile Strength
keywords: Atherosclerosis; Haemorrhage; Lipid; Material property; Thrombus