Mechanical and structural properties of different types of human aortic atherosclerotic plaques

Effect of collagen fibres and elastic lamellae content on the mechanical behaviour of abdominal aortic aneurysms

“…7) had a different characteristic in terms of low-and high-stretch domains. This results from the participation of elastic lamellae and collagen fibres in the load transfer process, which is typical of soft tissues rich in collagen [14]- [16], [31]. The above phenomenon has been well described [12]; the operational ranges of both structures have been defined using techniques of selective digestion of load-bearing components from aortic walls, separately elastic lamellae and collagen fibres.…”

“…Despite the fact that the performed correlation analyses accurately reflect the dependence of individual mechanical parameters on the contents of load-bearing structural components, this dependence is not exhaustive. Assuming that, unlike in the remodelling of arterial walls during the development of atherosclerosis [14], [17], no atypical formations appear in the structure of AAAs as a result of remodelling, there are at least several properties of the fibrotic extracellular matrix that can significantly affect the mechanical properties and parameters of material models. These include, among others, the degree of collagen crosslinking, collagen turn-over, degree of collagen packing, fragmentation of elastic lamellae, degree of hydration (proteoglycan content), and spatial fibre arrangement, described here by the angle between the circumferential direction and the main directions of the fibres ().…”

“…The initial geometric dimensions of the specimens were as follows: length l 0 = 25 (±0.5) mm and width w 0 = 5 (±0.1) mm. The width-to-length (WL) ratio was maintained at 0.2:1 as the most suitable for tensile testing [14], [29]. The specimens were mounted on a testing machine (Synergie 100, MTS) with flat clamps covered with rigid elastomer.…”

“…The mechanical parameters were obtained from the plots in the following steps ( Fig. 3) discussed in previously published papers [6], [8], [13], [14], [31]. Firstly, at the maximum point of the curve, the stress ( M ) values were determined, representing the mechanical failure of the specimens under uniaxial loading, and the maximum tangent modulus (MTM), determined as the maximum tangential slope to the Cauchy stress-stretch ratio curves.…”

“…Both normal and aneurysmal arterial tissues subjected to uniaxial loading exhibit strong nonlinear behaviour with an exponential stiffening effect at high-strain domains that is typical of soft tissues [12], [14]- [17]. Arterial walls are considered anisotropic, incompressible [2], and subjected to finite strains with negligible shear deformation [13], [21].…”