The overall goal of this project is to provide a set of tools for evaluating the performance of devices that are used in the endovascular repair of aortic disease. There has been a surge in the application of endovascular treatment. However, there is little scientific guidance on what the important features of an implanted device should be. This project will provide the tools for determining the hemodynamic impact of device characteristics and will assist in determining the most suitable design on a patient-by-patient basis. The primary aim of this project is to extend our Computational Fluid Dynamics capabilities for the rapid description and evaluation of hemodynamic forces on devices used for treating aneurysms of the abdominal aorta. Validation of the simulation software will be provided by innovative imaging techniques. Numerical algorithms will be developed to describe the hemodynamics in the vasculature before intervention and following the simulated insertion of a device. These capabilities will permit the assessment of the forces that tend to cause a stent- graft to migrate or to disassemble. It will also provide the ability to reduce the likelihood that there will be regions of pronounced recirculation with potential for thrombus formation. Advanced imaging methods will be used to provide a full description of the lumenal surface at multiple points through the cardiac cycle. Improvements in Magnetic Resonance Imaging pulse sequence design, radio frequency coils, and the use of contrast agents will be pursued to provide this capability. In addition, to establish boundary conditions for the numerical computations, flow velocities will be measured pre intervention using Magnetic Resonance Velocimetry. Finally, a cohort of patients scheduled for AAA repair will be recruited and the results of patient- specific computations of hemodynamic forces will be compared to temporal changes in device conformation. This project is a collaborative effort between imaging scientists, fluid dynamics engineers, and clinicians. It will provide a systematic engineering framework in which the design and function of interventional devices can be improved. Potential sources of device failure will be identified and eliminated. These improvements will benefit the large numbers of individuals who are likely to receive treatment with endovascular stent-grafts in the coming years.
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