Biomechanical computational models used more and more in medical research as well as in clinical applications need mathematical description of soft tissues with their very complex mechanical behaviour. They show large deformations with stress softening during cyclic loading, being moreover time-dependent due to their viscoelasticity, anisotropic due to fibrous structure and dependent on tissue excitation in case of muscular tissues, including smooth muscle cells in arterial walls. They are capable to adapt to the acting load (tissue remodelation) and to self-repair (healing) in case of damage or failure (rupture of fibres, etc.) This paper deals with constitutive description of passive elastic response of soft tissues to the acting load and with the ways, how the anisotropic structure of the tissue can be reflected. For this purpose, the spatial arrangement of fibres in the tissue needs to be detected and mathematically described. Lack of data on fibre arrangement in soft tissues and their interpatient variability is a major limiting factor for anisotropic constitutive description of soft tissues. Some problems related to transformation of results of mechanical tests and histological analyses of arterial tissues into parameters applicable in constitutive models are addressed as well.
Atherosclerosis is a life threatening cardiovascular disease causing lipoprotein accumulation within intima layer of artery wall and thus its thickening. Later stages are characterized by plaque formation with a lipid core separated from lumen by fibrous cap. In case of carotid arteries (CA), rupture of the plaque often results in a stroke. Detailed understanding of mechanical properties of atherosclerotic arteries and their components is essential for improvement of computer models used for prediction of plaque rupture. Samples of atherosclerotic CA from carotid endarterectomy were kept either in saline solution or in formaldehyde solution and then underwent uniaxial tensile testing in two directions. Statistical analysis of the obtained stressstrain responses shows that formaldehyde treatment of the tissue increases significantly the mean stiffness and reduces the dispersion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.