Biomechanical properties of the porcine thoracic aorta: An in- depth analysis of elastic modulus, stress-strain behavior and tissue toughness with regard to anatomical location and loading orientation

The mechanical integrity of the aortic wall is crucial for its physiological function and susceptibility to vascular pathologies. This study provides a systematic biomechanical characterization of the porcine aorta, focusing on regional and orientation-dependent variations in stiffness, strength, and tissue toughness. A total of 480 specimens from ten porcine aortas were obtained from defined anatomical regions and subjected to uniaxial tensile testing in circumferential and longitudinal orientations. No significant differences were found regarding specimen position (anterior, posterior, left, right), whereas biomechanical properties varied along the cranial–caudal axis in a parameter- and orientation-dependent manner. The high-strain modulus, and rupture stress in longitudinal specimens, increased towards the distal aorta, with the most pronounced differences occurring between proximal and distal segments. Toughness decreased distally in circumferential specimens but increased in longitudinal specimens. Circumferential specimens exhibited higher stiffness, strength, and toughness at high strains, whereas at low strains longitudinal specimens tended to be stiffer. In longitudinal specimens, the intima consistently ruptured first, followed by the media and adventitia at higher strains; in circumferential specimens, all three layers ruptured simultaneously. These findings demonstrate distinct regional, orientation-, and strain-dependent biomechanical behavior of the porcine aorta and emphasize the importance of anatomical location and loading direction in experimental aortic biomechanics, biomechanical modeling, and the development of vascular devices.