Biomechanical property and modelling of venous wall

Abstract

Human saphenous vein has long been used as coronary artery bypass grafts to survive a heart arrested by blocked coronary arteries. Biomechanical properties of the saphenous vein can be critical because mismatch in the biomechanical property between a coronary artery and a graft will reduce graft patency and speed up disease development in the graft. In this paper hence the active and passive biomechanical behaviours of the human saphenous vein and other venous walls were reviewed extensively and comprehensively. The existing in vitro uniaxial, bulge, planar and tubular biaxial tensile testing methods, in vivo testing cases, property variables, various tested results, constitutive models and their mathematical modelling methods, viscoelasticity, and residual strain/stress are highlighted and summarized. It is demonstrated that the biomechanical properties of the human saphenous vein and other venous walls are not well documented, and their modelling approaches are limited and subjected to be updated in a great deal. Additionally, a few important research issues are proposed. The paper has provided a piece of useful information to investigation into coronary artery bypass grafts.

Mechanical and structural characterisation of the dural venous sinuses

“…Smooth muscle cells are posited as playing an important role in mediating vessel circumferential tension in vivo 70 and regional variations in smooth muscle content were observed in this study (see Table 2 ). However, while smooth muscle cells can contract and contribute to in vivo vessel mechanics, they become inactive in excised vascalature 71 . Thus, the smooth muscle content of the dural sinus tissue likely has a negligible effect on the tissue’s passive, ex vivo mechanical response.…”

Bioinspired Vascular Grafts

“…Pressure myography relies upon recording changes in diameter using a high-resolution camera placed over a conduit that is mounted onto small cannulae during the course of pressurization (Schjørring et al 2015). The pressure-diameter, stress-strain, and compliance characteristics of a saphenous vein are significantly different than those responses measured for arterial blood vessels (Li 2018). Due to reduced elastin content and a lower number of elastic lamellae, stiffening occurs at lower pressures (Fig.…”

“…3), with the saphenous vein exhibiting a significantly lower compliance (0.7-2.6%/100 mmHg) (Lee et al 2013). For this reason, when used as an arterial substitute, elevated arterial pressure induces increased stress in the vein wall, promotes smooth muscle cell proliferation and matrix production, and, as a consequence, increases the risk of intimal hyperplasia (Li 2018).…”

Tissue engineered vascular grafts

“…The dimensions of human blood vessels are, on average, 4 mm diameter and 1 mm thickness for arteries and 5 mm diameter and 0.5 mm thickness for veins, with 60 µm for the intima and 360 µm for the tunica media (Li, 2018, Neufurth et al, 2015. However, these dimensions are not available throughout the entire circulatory system, as the diameter can reach 3.5 cm in the ascending aorta (McComb et al, 2016), 2.5 cm in the inferior vena cava (Patil et al, 2016), and 3 µm in capillaries (Cortés-Sol et al, 2013).…”

“…Therefore, the characteristics of the arterial wall, such as elasticity, stiffness, and thickness, are key factors for the physiological condition of the cardiovascular system, causing severe diseases in the case of significant modifications (Mohiaddin, 2019, Peter et al, 2018. Moreover, the biomechanical properties of veins are equally important, characterized by active characteristics involving the contraction of smooth muscle cells under the action of a stimulus, and passive characteristics, associated with the elasticity and viscoelasticity of the wall under a transmural pressure (Li, 2018). The mechanism for pulse propagation involves the generation of a negative pressure gradient at the forefront, which will accelerate the blood, leading to a spatial gradient of flow rate with a higher flow rate entering than leaving a segment of the vessel.…”