Ragkousis Georgios E, Curzen Nick, Bressloff Neil W
Computational Engineering and Design Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.
Southampton University Hospitals NHS Trust, Southampton, UK; Faculty of Medicine, University of Southampton, Southampton, UK.
Med Eng Phys. 2014 Apr;36(4):467-76. doi: 10.1016/j.medengphy.2014.02.004. Epub 2014 Mar 7.
In percutaneous coronary intervention (PCI), stent malapposition is a common complication often leading to stent thrombosis (ST). More recently, it has also been associated with longitudinal stent deformation (LSD) normally occurring through contact of a post balloon catheter tip and the protruding malapposed stent struts. The aim of this study was to assess the longitudinal integrity of first and second generation drug eluting stents in a patient specific coronary artery segment and to compare the range of variation of applied loads with those reported elsewhere. We successfully validated computational models of three drug-eluting stent designs when assessed for longitudinal deformation. We then reconstructed a patient specific stenosed right coronary artery segment by fusing angiographic and intravascular ultrasound (IVUS) images from a real case. Within this model the mechanical behaviour of the same stents along with a modified device was compared. Specifically, after the deployment of each device, a compressive point load of 0.3N was applied on the most malapposed strut proximally to the models. Results indicate that predicted stent longitudinal strength (i) is significantly different between the stent platforms in a manner consistent with physical testing in a laboratory environment, (ii) shows a smaller range of variation for simulations of in vivo performance relative to models of in vitro experiments, and (iii) the modified stent design demonstrated considerably higher longitudinal integrity. Interestingly, stent longitudinal stability may differ drastically after a localised in vivo force compared to a distributed in vitro force.
在经皮冠状动脉介入治疗（PCI）中，支架贴壁不良是一种常见并发症，常导致支架内血栓形成（ST）。最近，它还与纵向支架变形（LSD）有关，这种变形通常是由于后扩张球囊导管尖端与突出的贴壁不良支架支柱接触所致。本研究的目的是评估第一代和第二代药物洗脱支架在特定患者冠状动脉节段中的纵向完整性，并将施加负荷的变化范围与其他地方报道的进行比较。在评估纵向变形时，我们成功验证了三种药物洗脱支架设计的计算模型。然后，我们通过融合一个真实病例的血管造影和血管内超声（IVUS）图像，重建了特定患者的狭窄右冠状动脉节段。在这个模型中，比较了相同支架以及一种改良装置的力学行为。具体来说，在每个装置展开后，在模型近端最贴壁不良的支柱上施加0.3N的压缩点负荷。结果表明，预测的支架纵向强度（i）在支架平台之间存在显著差异，其方式与实验室环境中的物理测试一致；（ii）相对于体外实验模型，体内性能模拟的变化范围较小；（iii）改良后的支架设计显示出显著更高的纵向完整性。有趣的是，与体外分布力相比，局部体内力作用后支架纵向稳定性可能有很大差异。
