adfa, p. 1, 2011. © Springer-Verlag Berlin Heidelberg 2011 Reconstruction of Stent Induced Loading Forces on the Aortic Valve Complex Raoul Hopf 1,* , Michael Gessat 3 , Volkmar Falk 2 , Edoardo Mazza 1 1 Institute of Mechanical Systems, Department of Mechanical Engineering, Swiss Federal Insti- tute of Technology (ETH), Switzerland {rhopf, emazza}@ethz.ch 2 Division of Cardiovascular Surgery, University Hospital Zurich, Switzerland volkmar.falk@usz.ch 3 Computer Vision Laboratory, Department of Electrical Engineering, Swiss Federal Institute of Technology (ETH), Switzerland mgessat@ethz.ch Abstract. In order to evaluate the performance of stents used in transcatheter aortic valve implantation (T-AVI), finite element simulations are set up to re- construct patient specific contact forces between implant and its surrounding tissue. The reference geometry of the stent is obtained using micro-CT scanning data. A procedure is defined to create a numerically efficient and robust model of the stent made of beam elements. The model is validated with experiments applying representative loading cases. Post-op CT image data provide patient specific displacement maps used to define kinematic boundary conditions for the finite element simulation. An approach to deal with the issue of spurious strains induced by measurement uncertainties from CT images is proposed. Maps of radial forces acting on the aortic tissue are obtained. Keywords: tavi, aortic stent, corevalve, simulation, contact forces 1 Introduction Knowledge about the contact forces between a medical implant and its surrounding tissue can provide essential information on the overall performance of the implant. In particular, in the case of transcatheter aortic valve implantation (T-AVI). Insufficient contact forces between stent and tissue might cause paravalvular leaks [1]. On the contrary, excessive contact forces are suspected to impair the conductibility of the atrioventricular (AV) node, the bundle of His, and/or the left bundle branch. All three result in bradicaridal arrhythmia, which is a common complication after T-AVI, usu- ally requiring pacemaker implantation [2]. The two main risk factors which could be identified as significant in clinical studies are (i) the type of valve selected for implan- tation and (ii) valve oversizing (resulting in high radial loads) [2,3]. These findings indicate a connection between mechanical stress induced on the tissues and the neces- sity for a pacemaker after T-AVI. Nevertheless, there exists no quantitative investiga- tion of this relationship, which would allow predicting or help reducing the onset of conduction abnormalities after T-AVI. Demirci, Lee, Radeva, Unal (Eds.): MICCAI-STENT 2012. 104