Investigation of the effects of endovascular prostheses on cardiovascular fluid-structure interactions

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The use of endovascular stents for management of arterial disease is a rapidly emerging area of importance as it is the preferred choice in the management of occlusive, degenerative and aneurismal disease. A stent is inserted into a vessel to re-establish the vessel diameter, whether that is for re-expansion of an obstruction (stenosis) or to contain the flow through a vessel enlargement (aneurysm - see Figure). Despite these differing clinical requirements, all devices must fundamentally adhere to the overarching mechanical principle of appropriate generation of radial force for good approximation of the vessel wall in order that the desired clinical outcome is achieved. If the stent applies too much or too little force the patency of the stent can be compromised. Many clinical issues arise from the compliance mismatch that occurs between the stented region and the native vessel. Compliance mismatches from stents placed in the aorta can produce over dilation, vessel scarring and increased wave reflections resulting in higher blood pressure. Changes in blood flow velocity patterns and wall shear stress are also attributable to compliance mismatch and influence endothelial response, stent migration or blood leakage. In spite of the importance of these concerns, the forces acting on endovascular stents have not been well identified or defined, with little information available in the literature. The goal of my proposed research is to use experimental and numerical models to better understand the loading of endovascular stents, and how they affect vessel/stent compliance, wave propagation, wave reflection, wall shear stress, pressure and flow.