In Vivo Imaging and Computational Analysis of the Aortic Root. Application in Clinical Research and Design of Transcatheter Aortic Valve Systems

Valvular heart disease is a major cause of morbidity and mortality in developing and industrialized countries. For patients with advanced symptomatic disease, surgical open-heart valve replacement is an effective treatment, supported by long-term outcome data. More recently, less-invasive transcatheter approaches for valve replacement/implantation have been developed for patients that are not considered surgical candidates. An understanding of valvular and paravalvular anatomy and biomechanics is pivotal for the optimization of interventional valve procedures. Advanced imaging is increasingly used not only for clinical guidance but also for the design and further improvement of transcatheter valve systems. Computed tomography is particularly attractive because it acquires high-resolution volumetric data sets of the root including the leaflets and coronary artery ostia, with sufficient temporal resolution for multi-phasic analysis. These volumetric data sets allow subsequent 3-D and 4-D display, reconstruction in unlimited planes, and mathematical modeling. Computer modeling, specifically finite element analysis, of devices intended for implantation in the aortic root, allows for structural analysis of devices and modeling of the interaction between the device and cardiovascular anatomy. This paper will provide an overview of computer modeling of the aortic root and describe FEA approaches that could be applied to TAVI and have an impact on clinical practice and device design.