title: Simulation of self expanding transcatheter aortic valve in a realistic aortic root: implications of deployment geometry on leaflet deformation.
abstract: Self expanding Transcatheter Aortic Valve Replacements (TAVR) can conform to the geometry of the aortic annulus and the calcified leaflet complex, which may result in leaflet distortion and altered leaflet kinematics, but such changes have not yet been characterized. In this study we developed a computational model to investigate the deployment of a self expanding TAVR in a realistic aortic root model derived from multi-slice computed tomography (MSCT) images. We simulated TAVR crimping/deployment in realistic and idealized aortic root models, followed by diastolic loading of the TAVR leaflets in its final deployed configuration. The TAVR deployed in a realistic aortic root had increased peak loading in the commissural region of the leaflets compared to TAVRs under idealized circular deployment conditions (2.97 vs. 1.52 MPa). Furthermore, orientation of the TAVR in the asymmetric aortic annulus such that the commissures of the TAVR are aligned with the native valve commissures minimized the effect of TAVR stent distortion on peak stresses in the TAVR leaflets (2.97 vs. 2.35 MPa). We propose that preoperative planning of the orientation of the TAVR in the aortic root annulus might minimize the impact of potential stent distortion on leaflet function and may in turn increase long term leaflet durability.
authors.affiliation: Biomechanics Research Centre (BMEC), Department of Biomedical Engineering, National University of Ireland Galway, Galway, Ireland.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Gunning
authors.forename: Ted J
authors.initials: TJ
authors.lastname: Vaughan
authors.forename: Laoise M
authors.initials: LM
authors.lastname: McNamara
mesh_terms: D000369:Aged, 80 and over; D001021:Aortic Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D001696:Biomechanical Phenomena; D006328:Cardiac Catheterization; D003198:Computer Simulation; D020342:Finite Element Analysis; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006801:Humans; D008954:Models, Biological; D061330:Multidetector Computed Tomography; D015607:Stents