Alteration of hemodynamics in aneurysm models by stenting: Influence of stent porosity
Alteration of hemodynamics in aneurysm models by stenting: Influence of stent porosity
复制标题
DOI：
10.1007/bf02684187
复制
发表时间：
1997-05-01
影响因子：
3.8
通讯作者：
Wakhloo, AK
中科院分区：
文献类型：
--
作者：
Lieber, BB;Stancampiano, AP;Wakhloo, AK
脑血管疾病微创治疗的最新进展包括在动脉中放置支架来治疗动脉瘤。初步临床观察和实验研究表明，血管内支架穿过孔口可能导致血栓形成并随后导致动脉瘤闭塞。由于引入支架而引起的血管局部血流动力学的改变尚不清楚。我们研究了支架植入引起的局部血流动力学的变化。使用罗丹明染料的激光诱导荧光来可视化实验流动装置中的脉动流动模式。测试单元被构造成矩形形状，以便于在有或没有多孔支架的情况下对载瘤血管和动脉瘤模型中的流动模式进行不受干扰的纵向视图。研究了各种孔隙率（76%、80%、82% 和 85%）的编织镍钛合金支架。选定的流体动力学相似性参数（雷诺数和沃默斯利数）代表通常在人类高流量、较大动脉（例如颈动脉）和低流量、较小动脉（例如椎动脉）中发现的情况。较大动脉的平均雷诺数为 180，最大/最小值为 490/-30，沃默斯利数为 5.3。较小动脉的平均雷诺数为 90，最大/最小值为 230/2，沃默斯利数为 2.7。对于建模的较大动脉，在动脉瘤孔口放置孔隙率最低的支架会导致动脉瘤涡流速度降低，并减少与载瘤血管血流的相互作用。对于较小的动脉，相同孔隙率的支架导致载瘤血管/动脉瘤血流相互作用显着减少，并且在动脉瘤圆顶中出现富含罗丹明染料的非循环新月形流体。我们的结果可以帮助解释放置与局部血流动力学兼容的支架后动脉瘤内的体内血栓形成。
Recent developments in minimally invasive approach to cerebrovascular diseases include the placement of stents in arteries for treatment of aneurysms. Preliminary clinical observations and experimental studies have shown that intravascular stents traversing the orifice may lead to thrombosis and subsequent occlusion of the aneurysm. The alterations in vessel local hemodynamics due to the introduction of a stent are not yet well understood. We investigated changes in local hemodynamics resulting from stent implantation. Pulsatile flow patterns in an experimental flow apparatus were visualized using laser-induced fluorescence of rhodamine dye. The test cells were constructed in a rectangular shape to facilitate an undisturbed longitudinal view of flow patterns in parent vessel and aneurysm models with and without porous stents. Woven nitinol stents of various porosities (76%, 80%, 82%, and 85%) were investigated. The selected fluid dynamic similarity parameters (Reynolds and Womersley numbers) represented conditions usually found in high-flow, larger arteries in humans (such as the carotid artery) and low-flow, smaller arteries (such as the vertebral artery). The mean Reynolds number for the larger arteries was 180, with maximum/minimum values of 490/-30 and the Womersley number was 5.3. The mean Reynolds number for the smaller arteries was 90, with maximum/minimum values of 230/2, and the Womersley number was 2.7. For the larger arteries modeled, placement of a stent of the lowest porosity across the aneurysm orifice resulted in reduction of aneurysmal vortex speed and decreased interaction with parent vessel flow. For smaller arteries, a stent of the same porosity led to a substantial reduction of parent vessel/aneurysmal flow interaction and the appearance of a nonrecirculating crescent of fluid rich in rhodamine dye in the aneurysm dome. Our results can help explain in vivo thrombus formation within an aneurysm after placement of a stent that is compatible with local hemodynamics.