Stented Artery Wall Stresses and Retenosis

描述（由申请人提供）：球囊血管成形术和支架植入术是用于治疗动脉粥样硬化的技术，其使用越来越多。不幸的是，有20-30%的风险在治疗的动脉中形成新的阻塞。血管支架的恢复可能与其产生的机械条件有关。最近在支架血管中的研究揭示了复杂的流场，包括大尺度涡流和支柱之间的流动停滞。在支架的近端和远端也预测了异常高的固体壁应力集中。支架对动脉的慢性力也限制了其经历正常的生理变形。基于先前对动脉壁对机械环境中类似变化的反应的研究，可以合理预期支架植入术的这一方面会影响再狭窄。尽管支架设计在产生已知会损害动脉的机械现象方面至关重要，但很少关注对支架失效的影响以及通过更好的设计改善支架性能的方法。本提案中概述的研究基于以下假设：机械现象是血管支架临床失效的部分原因。本研究的具体目的包括使用计算技术构建支架动脉的真实力学模型。将优化支架结构，以最大限度地减少动脉壁上的应力，同时最大限度地增加正常生理变形量。精心设计的动物研究将证实机械因素在炎症反应中的重要性。长期目标是利用这些信息来帮助开发下一代支架，其中动脉力学的作用是首要考虑因素。

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.