Transcatheter&nbsp;heart valve interventions (THVI) are the norm for nonsurgical intervention in patients with heart valve disease and are evolving as the new norm for (older) patients at high surgical risk. To expand the spectrum of patients who can benefit from these interventions, we need to deepen our understanding of several post-intervention scenarios such as&nbsp;paravalvular&nbsp;regurgitation, valve migration, valve durability, etc. Computer simulations can provide us with predictive diagnosis, given patient-specific information, and help clinicians evaluate the outcome of such interventions. For example, we can predict the effect of valve size and geometry, material properties, and implantation position on the blood flow pattern, contact pressures, and post-operative deformations. We have developed a&nbsp;coupled&nbsp;fluid-structure interaction&nbsp;(FSI)&nbsp;framework of the left cardiovascular system to enable such patient-specific diagnostics. Our framework consists of several components. A four-chamber finite element model of the human cardiac system using cubic-Hermite meshes with extraordinary nodes is coupled with a lumped-parameter circulation model to simulate a complete cardiac cycle. Fiber orientations were interpolated within the mesh using the Log-Euclidean method,&nbsp;with the fiber orientation in the ventricles varying gradually from +60° at epicardium to -60° at endocardium with respect to&nbsp;the&nbsp;circumferential&nbsp;direction. The resultant geometry and deformations of this biomechanical simulation are used as input for our cardiac FSI simulation. To solve the heart valve FSI problem, we use the&nbsp;immersogeometric&nbsp;analysis (IMGA) method, which effectively deals&nbsp;with simulations involving structures with&nbsp;a&nbsp;complex motion that leads to large deformations of the fluid domain, including changes in topology. This method&nbsp;immerses&nbsp;the&nbsp;CAD boundary representation (B-rep) of&nbsp;a&nbsp;complex design structure&nbsp;into a non-boundary-fitted discretization of the surrounding fluid domain&nbsp;to perform the fluid simulation. The&nbsp;fluid simulation is performed&nbsp;using a hybrid arbitrary&nbsp;Lagrangian-Eulerian/IMGA framework to solve the hemodynamics of the heart and the structural mechanics of the bioprosthetic&nbsp;heart&nbsp;valve&nbsp;(BHV).&nbsp;The&nbsp;leaflets of the BHVs are modeled as thin shells using incompressible Fung-type material under tensile loading.&nbsp;This framework provides insights into the hemodynamic behavior of the heart, which can enable us to develop optimal valve designs and better pre-surgical planning.&nbsp;References:&nbsp;Fei&nbsp;Xu, Emily L. Johnson,&nbsp;Chenglong&nbsp;Wang, Arian Jafari, Cheng-Hau&nbsp;Yang, Michael S. Sacks, Adarsh Krishnamurthy, Ming-Chen Hsu; Computational investigation of left ventricular hemodynamics following bioprosthetic aortic and mitral valve replacement, Mechanics Research Communications, In Press, 2020.&nbsp;Arian Jafari, Edward Pszczolkowski, Adarsh Krishnamurthy; A framework for biomechanics simulations using four-chamber cardiac models, Journal of Biomechanics, 91:92–101, 2019.&nbsp;

A Framework for Coupled Left Ventricular and Atrial Fsi Simulations With Bioprosthetic Valves

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.