Department of Surgery, University of Nebraska Medical Center, 987690 Nebraska Medical Center, Omaha, NE 68198-7690, USA.
Department of Surgery, University of Nebraska Medical Center, 987690 Nebraska Medical Center, Omaha, NE 68198-7690, USA
J R Soc Interface. 2018 Aug;15(145). doi: 10.1098/rsif.2018.0475.
High failure rates of femoropopliteal artery (FPA) interventions are often attributed to severe mechanical deformations that occur with limb flexion. One of these deformations, cross-sectional pinching, has a direct effect on blood flow, but is poorly characterized. Intra-arterial markers were deployed into = 50 cadaveric FPAs (80 ± 12 years old, 14F/11M), and limbs were imaged in standing, walking, sitting and gardening postures. Image analysis was used to measure marker openings and calculate FPA pinching. Parametric finite element analysis on a stent section was used to determine the optimal combination of stent strut amplitude, thickness and the number of struts per section to maximize cross-sectional opening and minimize intramural mechanical stress and low wall shear stress. Pinching was higher distally and increased with increasing limb flexion. In the walking, sitting and gardening postures, it was 1.16-1.24, 1.17-1.26 and 1.19-1.35, respectively. Stent strut amplitude and thickness had strong effects on both intramural stresses and pinching. Stents with a strut amplitude of 3 mm, thickness of 175 µm and 20 struts per section produced pinching and intramural stresses typical for a non-stented FPA, while also minimizing low wall shear stress areas, and ensuring a stent lifespan of at least 10 cycles. These results can help guide the development of improved devices and materials to treat peripheral arterial disease.
股浅动脉（FPA）介入治疗的失败率较高，通常归因于肢体弯曲时发生的严重机械变形。这些变形之一，即横截面积的挤压，直接影响血流，但特征描述较差。将动脉内标记物放置在 = 50 个尸体 FPA（80 ± 12 岁，14 女/11 男）中，在站立、行走、坐姿和园艺姿势下对肢体进行成像。使用图像分析来测量标记物开口并计算 FPA 挤压。对支架部分进行参数有限元分析，以确定支架支柱幅度、厚度和每个支架段的支柱数量的最佳组合，以最大化横截面积开口，最小化壁内机械应力和低壁剪切应力。挤压在远端更高，并随肢体弯曲增加而增加。在行走、坐姿和园艺姿势下，分别为 1.16-1.24、1.17-1.26 和 1.19-1.35。支架支柱幅度和厚度对壁内应力和挤压都有强烈影响。具有 3 毫米支柱幅度、175 µm 厚度和每个支架段 20 个支柱的支架产生的挤压和壁内应力与未支架 FPA 典型的挤压和壁内应力相似，同时还最小化了低壁剪切应力区域，并确保支架的使用寿命至少为 10 个循环。这些结果可以帮助指导开发改进的设备和材料来治疗外周动脉疾病。
