Purpose

Multiple overlapping uncovered stents (MOUS) are employed to promote false lumen thrombosis in the aortic dissections (AD), when the tears are in close vicinity to the branch vessels. However, the overall rate of false lumen thrombosis remains unsatisfactory. This study was performed to investigate the hemodynamic influence of MOUS on aortic dissection to shed some light on the mechanism of post-stenting false lumen thrombosis.

Methods

An anatomically accurate computational fluid dynamics model was developed to investigate the hemodynamics of AD. A parametric study was carried out to demonstrate the hemodynamic influence of MOUS in various post-surgery scenarios featuring the representative surgical strategies involving MOUS.

Results

The use of reduced-porosity MOUS slowed the blood flow in the false lumen and decreased the wall shear stress. MOUS depressed the false lumen and enlarged the true lumen, without significantly altering the blood outflow distribution among the branch vessels. Compared with MOUS-alone and stent graft-alone scenarios, the combination of MOUS and stent graft generated a substantially large region of stagnant flow. The active flow was confined to an area in close vicinity to the tears covered by the MOUS, which perfuse the right renal artery in the false lumen.

Conclusions

MOUS helps to generate a favored hemodynamic environment for thrombus formation in the false lumen. Application of MOUS along with covered stent grafts may represent a more effective treatment for AD than utilizing MOUS or stent graft alone.

中文翻译：

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多个重叠的未发现支架对主动脉夹层的血流动力学影响：假性管腔血栓形成的手术策略和意义。

目的

当眼泪靠近分支血管时，使用多个重叠的未覆盖支架（MOUS）来促进主动脉夹层（AD）中的假管腔血栓形成。然而，假内腔血栓形成的总体速度仍然不能令人满意。这项研究的目的是调查MOUS对主动脉夹层的血流动力学影响，以阐明支架后假管腔血栓形成的机制。

方法

建立了解剖学上准确的计算流体动力学模型，以研究AD的血液动力学。进行了一项参数研究，以证明MOUS在各种手术后场景中的血液动力学影响，其特征在于涉及MOUS的代表性手术策略。

结果

孔隙率降低的MOUS的使用减慢了假管腔中的血液流动并降低了壁切应力。MOUS压低了假腔并扩大了真腔，而没有显着改变分支血管之间的血液流出分布。与仅使用MOUS和仅使用支架移植物的情况相比，MOUS和支架移植物的组合产生了很大的停滞区域。活跃的血流被限制在靠近MOUS覆盖的眼泪的区域，该眼泪在假腔内灌注右肾动脉。

结论

MOUS有助于为假管腔内的血栓形成创造良好的血液动力学环境。与单独使用MOUS或覆膜支架相比，将MOUS与覆盖的覆膜支架一起应用可能是一种更有效的AD治疗方法。