An Experimental Study on Circumferential Mechanical Properties of Porcine Descending Thoracic Aorta / 医用生物力学

ABSTRACT

Objective To study the mechanical properties of porcine descending aorta. Methods The porcine descending aortas were divided into 5 groups by the distance from the heart, and tissues in each group were subdivided into ventral-quadrant part and lateral-quadrant part. Stress-stretch curves were obtained by using uniaxial tension test. The moduli of elastic and collagen fiber and collagen fiber recruitment parameter of tissues in 5 groups (Position 1-5) were first analyzed by a classical mathematical model. Then the mechanical differences between tissues of ventral quadrant and lateral quadrant were compared. Results The modulus of circumferential collagen fibers increased gradually away from the heart. The modulus of circumferential elastic fibers had the same trend except for tissues at Position 5 (the most distal one). The elastic fibers modulus of tissues decreased at Position 5. At the most distal position, the circumferential and axial elastic fiber modulus of the lateral quadrant was lower than that of ventral quadrant by 19% and 33%, respectively. The axial and the elastic fiber modulus of the ventral quadrant was similar with that of tissues at Position 4 and 5. For the whole descending aorta, the circumferential collagen fiber modulus of the lateral quadrant was higher than that of ventral quadrant by 26% and the circumferential elastic fiber modulus of the lateral quadrant was higher than that of ventral quadrant by 16% at the proximal 4 positions. Conclusions The circumferential mechanical properties of porcine descending aorta were related with regions. The ventral quadrant of the most distal aorta showed abnormally soft trend. The research findings can be used to better understand the mechanism of aorta and improve the spatial accuracy of computer models.