Modelling left ventricular function under assist device support

Abstract

SUMMARYNumerical simulations provide a unique approach for investigating the impact of left ventricular assist devices (LVADs) on the pump function of the heart. To this end, the fictitious domain (FD) method was incorporated within a non-conforming coupled fluid-solid mechanics solver creating a model capable of capturing the full range of cardiac motion under LVAD support, including contact of the cannula with the ventricular wall. To demonstrate and verify the properties of the applied method, convergence studies were performed showing linear convergence for both a fluid only problem with an immersed rigid body, as well as a fluid-solid coupled problem with a fluid immersed rigid body interacting with the coupled elastic solid. The model was implemented on a left ventricular (LV) geometry constructed from human MRI data. Simulations were performed to compare LV function with an FD prescribed LVAD cannula and with a cannula applied as a Dirichlet boundary. Good agreement was observed between the simulations for myocardial deformation, major flow features and rates of energy transfer. Finally, an LV simulation was performed to bring the ventricular wall into contact with the cannula, demonstrating the applicability of the model to investigating LV function under LVAD support.

Modelling mitral valvular dynamics–current trend and future directions

“…A combined FD method and ALE was developed by Van de Vosse et al to simulate valvular dynamics in a simple left‐ventricular flow model. Recently, by implementing FD within a coupled ALE fluid‐structure framework, McCormick et al investigated the LV function under assist device support. The commercial explicit solver LS‐DYNA (Livermore Software Technology Corporation, Livermore, CA, USA) uses similar approach as the FD method and has been used to simulate MV FSI problems .…”

Toward GPGPU accelerated human electromechanical cardiac simulations

“…All CPU simulations were run in the finite element code Heart. Developed for modeling multi‐physics fluid‐structure interaction in the heart , Heart has been further developed to incorporate additional physical systems and provide flexible multi‐physics integration. Support for many finite element discretization schemes, physics, and coupling along with domain partition and parallelization are some of the core features of Heart.…”

Numerical investigation of the effect of cannula placement on thrombosis

“…However, detailed intraventricular flow fields in the LV cannot be directly observed through standard imaging modalities, e.g. magnetic resonance imaging (MRI) cannot be utilized due to metallic components in the pump [10]. Advanced ultrasound techniques such as the transthoracic echocardiography, have often been used to compensate for the insufficiency of standard imaging modalities.…”