Biaxial Mechanical Properties of Porcine Ascending Aortic Wall Tissue
Mark A. Nicosia PhD, Jeffrey S. Kasalko MS, Richard P. Cochran MD, Daniel R. Einstein, Karyn S. Kunzelman PhD

The study aim was to determine the biaxial material properties of porcine aortic root wall tissue. Tissue samples (20x20 mm) were obtained from the aortic root walls of 18 pigs and studied using a custom-built biaxial tensile testing apparatus. The root wall tissue was less stiff in the longitudinal direction than in the circumferential direction, and mechanical interaction was present between the two axes. Additionally, anterior tissue samples were less stiff than posterior samples. All tissue samples exhibited a linear stress-strain relationship up to 40% strain, in contrast to aortic leaflet tissue, which was highly non-linear. These results demonstrated that porcine aortic root wall tissue is an anisotropic material with linear elastic properties, in contrast to leaflet tissue.