Session: 12-26-01: Data-Driven Modeling and Simulation for Computational Biomedicine

Paper Number: 71908

Start Time: Friday, 03:55 PM

71908 - A Framework for Coupled Left Ventricular and Atrial Fsi Simulations With Bioprosthetic Valves 

Transcatheter 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 paravalvular 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 coupled fluid-structure interaction (FSI) 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, with the fiber orientation in the ventricles varying gradually from +60° at epicardium to -60° at endocardium with respect to the circumferential 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 immersogeometric analysis (IMGA) method, which effectively deals with simulations involving structures with a complex motion that leads to large deformations of the fluid domain, including changes in topology. This method immerses the CAD boundary representation (B-rep) of a complex design structure into a non-boundary-fitted discretization of the surrounding fluid domain to perform the fluid simulation. The fluid simulation is performed using a hybrid arbitrary Lagrangian-Eulerian/IMGA framework to solve the hemodynamics of the heart and the structural mechanics of the bioprosthetic heart valve (BHV). The leaflets of the BHVs are modeled as thin shells using incompressible Fung-type material under tensile loading. 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. 

References: 

Fei Xu, Emily L. Johnson, Chenglong Wang, Arian Jafari, Cheng-Hau 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. 

Arian Jafari, Edward Pszczolkowski, Adarsh Krishnamurthy; A framework for biomechanics simulations using four-chamber cardiac models, Journal of Biomechanics, 91:92–101, 2019. 

Presenting Author: Mehdi Saraeian Iowa State University

Authors:

Mehdi Saraeian Iowa State University
Arian Jafari Iowa State University
Remy Braun Iowa State University
Ming-Chen Hsu Iowa State University
Adarsh Krishnamurthy Iowa State University