Characterisation of Mechanical Properties of Human Pulmonary and Aortic Tissue

The aim of this study is to characterise the mechanical properties of aortic and pulmonary arterial tissue, thereby comparing both tissue types and investigating the effect of lung-affecting disease on the mechanical behaviour of pulmonary arteries. Force-controlled, planar biaxial tensile tests were performed on human tissue samples collected from donors and receptors undergoing lung transplantation. In total 8 pulmonary donor, 6 pulmonary receptor and 6 aortic donor samples were tested and analysed. Donor samples are considered to be healthy, while receptors provided pathological tissue. The stiffness and strength of each sample were calculated from the stress-strain curves and a statistical analysis was performed between the three tissue groups (pulmonary donor, pulmonary receptor and aortic donor). The stiffness of aortic donor tissue was found to be significantly higher than for pulmonary donor tissue (p < 0.01) at physiological systolic stresses. The same could be observed for the strength (p < 0.05). Pulmonary samples were, however, significantly stiffer than aortic samples at stresses in the physiological range of aorta (p < 0.01). There was no significant difference found between the donors and receptors for pulmonary samples. The fact that the physiological pressure in the aorta is fivefold higher than in the pulmonary artery is also reflected in its stiffness and strength.