Intermediate fenestrations reduce flow reversal in a silicone model of Stanford Type B aortic dissection
Intermediate fenestrations reduce flow reversal in a silicone model of Stanford Type B aortic dissection
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DOI：
10.1016/j.jbiomech.2019.06.019
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发表时间：
2019-08-27
影响因子：
2.4
通讯作者：
Ku, David N.
中科院分区：
文献类型：
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作者：
Birjiniuk, Joav;Veeraswamy, Ravi K.;Ku, David N.
脉动的三维血流动力学力影响血栓形成，并可能决定主动脉夹层的进展。内膜瓣开窗和血压是这种病理学中临床相关的变量，但它们对解剖血流动力学的影响知之甚少。本研究的目的是表征这些对解剖模型中血流的影响，以更好地指导预防动脉瘤形成和假腔血流的干预措施。根据患者图像制作带有可移动内膜瓣的主动脉夹层硅胶模型，并将其安装在具有脉动流的流动回路中。通过 4 维流 MRI 获取流场，从而实现相关流体力学的量化和可视化。在紧邻近端入口撕裂处的开窗处观察到脉动涡流和喷射状结构。添加开窗后，假腔流逆转显着减少，从两撕裂解剖中的 19.2 +/- 3.3% 减少到随后每次开窗的 4.67 +/- 1.5% 和 4.87 +/- 1.7%。相反，增加压力不会导致流速、流动反转和涡流形成的明显差异。与两撕裂解剖相比，增加中间撕裂的数量减少了血流逆转，这可以防止假腔血栓形成，促进持续的假腔血流。涡流是由远端撕裂部位的腔内流体运动引起的，这可能导致相对壁的退化。压力增加不会影响测量到的血流模式，但可能会导致主动脉壁应力集中。使用 4D MRI 对疾病进行功能和解剖学评估可能有助于对该人群中的患者风险进行分层。 (C) 2019 Elsevier Ltd. 保留所有权利。
Pulsatile, three-dimensional hemodynamic forces influence thrombosis, and may dictate progression of aortic dissection. Intimal flap fenestration and blood pressure are clinically relevant variables in this pathology, yet their effects on dissection hemodynamics are poorly understood. The goal of this study was to characterize these effects on flow in dissection models to better guide interventions to prevent aneurysm formation and false lumen flow. Silicone models of aortic dissection with mobile intimal flap were fabricated based on patient images and installed in a flow loop with pulsatile flow. Flow fields were acquired via 4-dimensional flow MRI, allowing for quantification and visualization of relevant fluid mechanics. Pulsatile vortices and jet-like structures were observed at fenestrations immediately past the proximal entry tear. False lumen flow reversal was significantly reduced with the addition of fenestrations, from 19.2 +/- 3.3% in two-tear dissections to 4.67 +/- 1.5% and 4.87 +/- 1.7% with each subsequent fenestration. In contrast, increasing pressure did not cause appreciable differences in flow rates, flow reversal, and vortex formation. Increasing the number of intermediate tears decreased flow reversal as compared to two-tear dissection, which may prevent false lumen thrombosis, promoting persistent false lumen flow. Vortices were noted to result from transluminal fluid motion at distal tear sites, which may lead to degeneration of the opposing wall. Increasing pressure did not affect measured flow patterns, but may contribute to stress concentrations in the aortic wall. The functional and anatomic assessment of disease with 4D MRI may aid in stratifying patient risk in this population. (C) 2019 Elsevier Ltd. All rights reserved.