Stented Artery Wall Stresses and Retenosis

描述(由申请人提供)：球囊血管成形术和支架置入术是治疗动脉粥样硬化的技术，使用越来越多。不幸的是，有20%-30%的风险在治疗后的动脉中形成新的阻塞。血管支架的再狭窄可能与其造成的机械条件有关。最近对支架血管的研究揭示了一个复杂的流场，包括大范围的涡流和支柱之间的流动停滞。在支架的近端和远端也预测到了异常高的固体壁应力集中。支架对动脉的慢性作用力也限制了它经历正常的生理变形。根据先前对动脉壁对机械环境中类似变化的反应的研究，有理由认为支架置入术的这一方面会影响再狭窄。虽然支架设计在造成已知的损伤动脉的机械现象方面是至关重要的，但对支架失败的影响以及如何通过更好的设计来改善支架性能的关注很少。这项建议中概述的研究是基于这样一个假设，即机械现象是血管支架临床失败的部分原因。这项研究的具体目标包括使用计算技术构建真实的支架动脉力学模型。支架结构将被优化，以最大限度地减少动脉壁上的应力，同时最大化正常的生理变形量。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的。

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.