Stented Artery Wall Stresses and Retenosis

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DESCRIPTION (provided by applicant): Balloon angioplasty and stenting are techniques for treating atherosclerosis that are increasing in use. Unfortunately, there is a 20-30% risk of a new blockage developing in the treated artery. Restenosis of vascular stents may be related to the mechanical conditions that they create. Recent investigations in stented vessels revealed a complex flow field including large-scale vortices and flow stagnation between the struts. Abnormally high solid wall stress concentrations have also been predicted at the proximal and distal ends of the stent. The chronic force of the stent against the artery also restricts it from experiencing normal, physiologic deformation. Based on previous studies of artery wall responses to similar changes in the mechanical environment, it is reasonable to expect that this aspect of stenting influences restenosis. Although stent design is crucial in creating mechanical phenomena known to be damaging to arteries, little attention has been given to the effects on stent failure, and ways to improve stent performance through better design. The research outlined in this proposal is based on the hypothesis that mechanical phenomena are, in part, responsible for clinical failures of vascular stents. The Specific Aims of this research include the construction of realistic mechanical models of stented arteries using computational techniques. The stent structure will be optimized to minimize stress on the artery wall, while maximizing the amount of normal, physiologic deformation. Carefully designed animal studies will provide confirmation of the importance of mechanical factors in inflammatory response. The long-term goal is to use this information to help develop the next generation of stents in which the role of arterial mechanics is a prime consideration.