The Influence of Aortic Valve Leaflet Material Models on Hemodynamic Features in Healthy and Pathological States

Cardiac blood outflow restriction is caused by calcific aortic stenosis, a gradual thickening of the aortic valve leaflets, and long-term fiber tissue remodeling. Surgeons have several options when replacing an aortic valve: they can employ minimally invasive techniques like transcatheter aortic valve implantation (TAVI) or perform open-heart surgery, which requires making an incision in the chest. There are several benefits and drawbacks to these kinds of surgeries. The Ozaki procedure, which replaces the aortic valve with tissue from an autologous pericardium, has been proposed recently. Although this approach shows promise in treating aortic valve disease, it lacks long-term outcomes and appropriate leaflet sizing selection. Surgeons can anticipate the results of each patient's operation with the use of numerical fluid simulations.

However, a question remains unanswered in the explanation of material models for leaflet mechanics. It can be challenging to choose the best model to explain various aortic valve diseases. We analyzed aortic valve leaflet material models numerically using 3D FSI simulation in order to characterize the hemodynamics in diseased, normal, and Ozaki situations. Furthermore, we disclose the displacement distributions, von Mises stress, and wall shear stress. We analyzed the isotropic hyperelastic model, the anisotropic hyperelastic model, and the elastic model in this study. Velocity, pressure, OSI, and TAWSS were also evaluated. We discovered that the proper model for leaflet simulation in the Ozaki case and the healthy state case involves the Holzapfel–Gasser–Ogden constitutive equation. In the case of pathology (calcification), it is better to adopt the elastic model.

The authors thank the Ministry of Science and Higher Education of the Russian Federation for their financial assistance within the framework of the state assignment for performing fundamental scientific research (FSNM-2023-0003 project).