Comparative analysis of ovine and human aortic valve tissue for bioprosthetic valve development using relaxation tests and numerical simulation

As the demand for aortic valve prostheses grows, optimizing their mechanical performance and durability is essential. While mechanical valves offer longevity, their need for lifelong anticoagulation limits their use, making bioprosthetic valves a preferred alternative. However, bioprosthetic valves made from bovine pericardium face durability challenges due to structural degradation. Given that valve functionality is heavily influenced by the collagen architecture and mechanical properties of the tissue, selecting an optimal replacement is essential. This study evaluates treated ovine aortic valves as an alternative material, comparing their mechanical behavior to native human valves. Tensile tests showed an elastic modulus of 20.17 MPa for treated ovine leaflets, while human leaflets ranged from 6.15 MPa to 28.10 MPa. Stress relaxation tests indicated a 41% stress reduction in treated ovine valves compared to 21% in human valves after 300 s, suggesting greater viscoelasticity. Finite element analysis revealed lower peak systolic stress in treated ovine valves (0.36 MPa vs. 0.72 MPa in human valves), with stress distributions aligning with clinically observed degradation sites. These findings highlight ovine tissue's potential for improved durability and flexibility, making it a strong candidate for next-generation bioprosthetic heart valves.