Timmins Lucas H, Meyer Clark A, Moreno Michael R, Moore James E
Department of Biomedical Engineering, Texas A&M University, College Station, TX 78843-3120, USA.
J Endovasc Ther. 2008 Dec;15(6):643-54. doi: 10.1583/08-2443.1.
To examine the solid mechanical effects of varying stent design and atherosclerotic plaque stiffness on the biomechanical environment induced in a diseased artery wall model.
Computational modeling techniques were employed to investigate the final radius of the lumen and artery wall stresses after stent implantation. Two stent designs were studied (one stiff and one less stiff). The stenotic artery was modeled as an axisymmetrical diseased vessel with a 20% stenosis by diameter. The material properties of the diseased tissue in the artery models varied. Atherosclerotic plaques half as stiff (0.5x), of equal stiffness (1.0x), or twice as stiff (2.0x) as the artery wall were investigated.
Final lumen radius was dependent on stent design, and the stiffer stent deformed the artery to an approximately 10% greater radius than the more compliant design. Alternatively, circumferential stress levels were dependent on both stent design and plaque material properties. Overall, the stiffer stent subjected the artery wall to much higher stress values than the more compliant design, with differences in peak values of 0.50, 0.31, and 0.09 MPa for the 2.0x, 1.0x, and 0.5x stiff plaques, respectively.
Evidence suggests that a judicious choice of stent design can minimize stress while maintaining a patent lumen in stenotic arteries. If confronted with a rigid, calcified plaque, stent design is more important, as design differences can impose dramatically different stress fields, while still providing arterial patency. Alternatively, stent design is not as much of an issue when treating a soft, lipid-laden plaque, as stress fields do not vary significantly among stent designs.
研究不同支架设计和动脉粥样硬化斑块硬度对病变动脉壁模型中诱导的生物力学环境的固体力学效应。
采用计算建模技术研究支架植入后管腔的最终半径和动脉壁应力。研究了两种支架设计（一种较硬，一种较软）。将狭窄动脉建模为直径狭窄20%的轴对称病变血管。动脉模型中病变组织的材料特性各不相同。研究了硬度为动脉壁一半（0.5倍）、硬度相同（1.0倍）或硬度为两倍（2.0倍）的动脉粥样硬化斑块。
最终管腔半径取决于支架设计，较硬的支架使动脉变形后的半径比顺应性较好的设计大约大10%。另外，周向应力水平取决于支架设计和斑块材料特性。总体而言，较硬的支架使动脉壁承受的应力值远高于顺应性较好的设计，对于硬度为2.0倍、1.0倍和0.5倍的斑块，峰值差异分别为0.50、0.31和0.09MPa。
有证据表明，明智地选择支架设计可以在保持狭窄动脉管腔通畅的同时将应力降至最低。如果面对坚硬的钙化斑块，支架设计更为重要，因为设计差异会产生截然不同的应力场，同时仍能保持动脉通畅。另外，在治疗柔软的富含脂质的斑块时，支架设计不是那么重要的问题，因为不同支架设计之间的应力场差异不大。
