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治疗动脉粥样硬化的技术，应用越来越广泛。不幸的是，有20-30%的风险在治疗后的动脉中形成新的阻塞。血管支架再狭窄可能与其所产生的机械条件有关。近年来对支架血管的研究表明，支架内存在复杂的流场，包括大范围的旋涡和支板之间的流动停滞。在支架的近端和远端也预测了异常高的固体壁应力浓度。支架对动脉的长期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类似机械环境变化的反应的研究，我们有理由认为支架置入的这一方面会影响再狭窄。尽管支架设计对于产生已知的损伤动脉的机械现象至关重要，但很少有人关注支架失效的影响，以及通过更好的设计提高支架性能的方法。本提案中概述的研究是基于这样一种假设，即机械现象是导致血管支架临床失败的部分原因。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。支架结构将被优化，以尽量减少对动脉壁的应力，同时最大限度地保持正常的生理变形。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主要考虑的因素。

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.