Zhao Shijia, Gu Linxia, Froemming Stacey R
Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.
J Biomech Eng. 2012 Dec;134(12):121005. doi: 10.1115/1.4023094.
The stent-artery interactions have been increasingly studied using the finite element method for better understanding of the biomechanical environment changes on the artery and its implications. However, the deployment of balloon-expandable stents was generally simplified without considering the balloon-stent interactions, the initial crimping process of the stent, its overexpansion routinely used in the clinical practice, or its recoil process. In this work, the stenting procedure was mimicked by incorporating all the above-mentioned simplifications. The impact of various simplifications on the stent-induced arterial stresses was systematically investigated. The plastic strain history of stent and its resulted geometrical variations, as well as arterial mechanics were quantified and compared. Results showed the model without considering the stent crimping process underestimating the minimum stent diameter by 17.2%, and overestimating the maximum radial recoil by 144%. It was also suggested that overexpansion resulted in a larger stent diameter, but a greater radial recoil ratio and larger intimal area with high stress were also obtained along with the increase in degree of overexpansion.
为了更好地理解动脉上生物力学环境的变化及其影响，人们越来越多地使用有限元方法来研究支架与动脉之间的相互作用。然而，球囊扩张式支架的展开过程通常被简化，没有考虑球囊与支架之间的相互作用、支架的初始压握过程、临床实践中常规使用的过度扩张，或其回弹过程。在这项研究中，通过纳入上述所有简化因素来模拟支架置入过程。系统地研究了各种简化因素对支架引起的动脉应力的影响。对支架的塑性应变历史及其导致的几何变化以及动脉力学进行了量化和比较。结果表明，未考虑支架压握过程的模型将最小支架直径低估了17.2%，并将最大径向回弹高估了144%。研究还表明，过度扩张会导致更大的支架直径，但随着过度扩张程度的增加，也会获得更大的径向回弹率和更大的高应力内膜面积。
