title: Local axial compressive mechanical properties of human carotid atherosclerotic plaques-characterisation by indentation test and inverse finite element analysis.
abstract: The fibrous cap of an atherosclerotic plaque may be prone to rupture if the occurring stresses exceed the strength of the cap. Rupture can cause acute thrombosis and subsequent ischaemic stroke or myocardial infarction. A reliable prediction of the rupture probability is essential for the appropriate treatment of atherosclerosis. Biomechanical models, which compute stresses and strain, are promising to provide a more reliable rupture risk prediction. However, these models require knowledge of the local biomechanical properties of atherosclerotic plaque tissue. For this purpose, we examined human carotid plaques using indentation experiments. The test set-up was mounted on an inverted confocal microscope to visualise the collagen fibre structure during the tests. By using an inverse finite element (FE) approach, and assuming isotropic neo-Hookean behaviour, the corresponding Young's moduli were found in the range from 6 to 891kPa (median 30kPa). The results correspond to the values obtained by other research groups who analysed the compressive Young's modulus of atherosclerotic plaques. Collagen rich locations showed to be stiffer than collagen poor locations. No significant differences were found between the Young's moduli of structured and unstructured collagen architectures as specified from confocal collagen data. Insignificant differences between the middle of the fibrous cap, the shoulder regions, and remaining plaque tissue locations indicate that axial, compressive mechanical properties of atherosclerotic plaques are independent of location within the plaque.
authors.affiliation: Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands. c.chai@tue.nl
authors.forename: Chen-Ket
authors.initials: CK
authors.lastname: Chai
authors.forename: Ali C
authors.initials: AC
authors.lastname: Akyildiz
authors.forename: Lambert
authors.initials: L
authors.lastname: Speelman
authors.forename: Frank J H
authors.initials: FJ
authors.lastname: Gijsen
authors.forename: Cees W J
authors.initials: CW
authors.lastname: Oomens
authors.forename: Marc R H M
authors.initials: MR
authors.lastname: van Sambeek
authors.forename: Aad
authors.initials: A
authors.lastname: van der Lugt
authors.forename: Frank P T
authors.initials: FP
authors.lastname: Baaijens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000503:physiopathology*; D003094:Collagen; D055119:Elastic Modulus; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000503:physiopathology*; D013314:Stress, Mechanical
chemical_list: D003094:Collagen