Fluid-structure-interaction analysis to investigate the effect of implantation height on hemodynamic performance in transcatheter aortic valve implantation

Purpose – Transcatheter aortic valve implantation (TAVI) is an effective and minimally invasive treatment for severe aortic stenosis. However, complications such as thrombus formation on transcatheter aortic valve (TAV) leaflets remain a concern, particularly in relation to implantation height. The purpose of this study is to numerically investigated the effect of the valve position of TAVI on the hemodynamics of TAV. Design/methodology/approach – A fluid-structure interaction (FSI) code was developed by using the finite element method (FEM) consisting of the semi-monolithic formulation for FSI; FEM formulation for a fully nonlinear constitutive equation for large deformation and a hyper-elastic Mooney–Rivlin model to describe the material of leaflets; unstructured dynamic remeshing method based on advancing front method (AFM). The present results have been analyzed by using two hemodynamic indices: time averaged wall shear stress (TAWSS) and blood residence time (BRT). Findings – The trend of thrombus volume of the neo-sinus versus TAV height was found to qualitatively agree well with clinical data. Furthermore, distributions of TAWSS and BRT on leaflet surfaces were found to promote the wash-out of blood on leaflets as the height increases; a strong inverse relationship between TAWSS and BRT was observed, emphasizing the role of implantation height in mitigating thrombotic risks. Originality/value – A semi-monolithic FEM with a dynamic remeshing technique was first developed to investigate the effect of TAVR position on leaflet wash-out through TAWSS and BRT. The present simulation results agreed well qualitatively with clinical reports showing that the proposed methodology can be a useful tool to evaluate thrombotic risk in TAVR.