Howell Benjamin A, Kim Tom, Cheer Angela, Dwyer Harry, Saloner David, Chuter Timothy A M
Division of Vascular Surgery, University of California at San Francisco, California 94143, USA.
J Endovasc Ther. 2007 Apr;14(2):138-43. doi: 10.1177/152660280701400204.
To assess the hemodynamic forces on a bifurcated abdominal aortic stent-graft under realistic conditions of flow, blood pressure, and sac pressure.
Computational fluid dynamics was used to study the temporal and spatial variations in surface pressure and shear through the cardiac cycle on models of bifurcated stent-grafts derived from computed tomography in 4 patients who had previously undergone endovascular repair of abdominal aortic aneurysm (AAA). The trunk, bifurcation, and limbs of the graft were analyzed separately and as parts of a unified whole. Analyses were repeated under varying conditions of sac pressure, reflecting different conditions of perigraft flow and sac diameter change.
Pressure-related forces were far larger than flow-related forces in all 3 segments of all 4 cases. The largest forces acted at the bifurcation of the stent-graft. High sac pressures, seen in patients with endoleak or aneurysm dilatation, were associated with reduced transmural pressure and low-pressure-derived forces.
Several parameters of stent-graft design affect the magnitude and distribution of forces on a bifurcated stent-graft. The forces on a stent-graft are also affected by the pressure within the aneurysm sac, which depends on stent-graft performance.
在血流、血压和瘤腔压力的实际条件下，评估分叉型腹主动脉覆膜支架移植物上的血流动力学作用力。
采用计算流体动力学方法，对4例先前接受过腹主动脉瘤（AAA）血管腔内修复术患者的计算机断层扫描所得的分叉型支架移植物模型，研究心动周期内表面压力和剪切力的时空变化。分别对移植物的主干、分叉处和分支进行分析，并将其作为一个统一整体的部分进行分析。在不同瘤腔压力条件下重复进行分析，以反映移植物周围血流和瘤腔直径变化的不同情况。
在所有4例患者的所有3个节段中，与压力相关的作用力远大于与血流相关的作用力。最大的作用力作用于支架移植物的分叉处。内漏或动脉瘤扩张患者出现的高瘤腔压力与跨壁压力降低和低压衍生作用力有关。
支架移植物设计的几个参数会影响分叉型支架移植物上作用力的大小和分布。支架移植物上的作用力也受动脉瘤腔内压力的影响，而动脉瘤腔内压力取决于支架移植物的性能。
