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.