Purpose

Effective, consistent, and complication-free treatment of cerebral bifurcation aneurysms remains elusive despite a pressing need, with the majority of lesions presenting in such locations. Current treatment options focus either on aneurysm coil retention, supported by a stent-like device positioned in the parent vessel lumen, or intrasaccular devices that disrupt flow within the aneurysm dome. A third alternative, i.e., the use of conventional (intraluminal) flow-diverters to treat such bifurcation aneurysms raises the problem that at least one daughter vessel needs to be jailed in such a deployment. The eCLIPs is a stent-like device that offers the possibility of flow-diversion at the aneurysm neck, without the drawbacks of daughter vessel occlusion or those of intrasaccular deployment.

Methods

In this study the eCLIPs device was virtually deployed in five cerebral bifurcation aneurysms and compared with a conventional tubular flow-diverter device. Computational fluid dynamics (CFD) simulations of the aneurysm haemodynamic environment pre- and post-implantation were conducted, and focussed on metrics associated with successful aneurysm occlusion. Absolute and relative reductions in aneurysm inflow rate (Q) and time-averaged wall shear stress (TAWSS) were recorded.

Results

The eCLIPs device was found to perform in a similar qualitative fashion to tubular flow-diverters, with overall reduction of metrics being somewhat more modest however, when compared to such devices. Aneurysm inflow reduction and TAWSS reduction were typically 10–20% lower for the eCLIPs, when compared to a generic flow diverter (FD_BRAIDED) similar to devices currently in clinical use. The eCLIPs was less effective at diffusing inflow jets and at reducing the overall velocity of the flow, when compared to these devices. This result is likely due to the larger device pore size in the eCLIPs. Notably, it was found that the eCLIPs provided approximately equal resistance to flow entering and exiting the aneurysm, which was not true for the FD_BRAIDED device, where high-speed concentrations of outflow were seen at the aneurysm neck along with local TAWSS elevation. The clinical implications of such behaviour are not examined in detail here but could be significant.

Conclusions

Our findings indicate that the eCLIPs device acts as a flow-diverter for bifurcation aneurysms, with somewhat diminished occlusion properties comparing to tubular flow diverters but without the jailing and diminished flow evident in a daughter vessel associated with use of conventional devices.

中文翻译：

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eCLIPs 装置和传统分流器治疗脑分叉动脉瘤的虚拟比较。

目的

尽管需求迫切，但脑分叉动脉瘤的有效、一致且无并发症的治疗仍然难以实现，大多数病变出现在这些位置。目前的治疗选择要么集中在动脉瘤线圈保留上，由定位在载瘤血管腔中的类似支架的装置支持，要么集中在破坏动脉瘤穹顶内流动的囊内装置上。第三种选择，即使用传统的（管腔内）分流器来治疗这种分叉动脉瘤提出了这样的问题，即至少需要在这种部署中关押一个子血管。eCLIPs 是一种类似支架的装置，可在动脉瘤颈部提供分流的可能性，而没有子血管闭塞或囊内部署的缺点。

方法

在这项研究中，eCLIPs 装置实际上部署在五个大脑分叉动脉瘤中，并与传统的管状分流器装置进行了比较。对植入前和植入后的动脉瘤血液动力学环境进行了计算流体动力学 (CFD) 模拟，重点关注与成功动脉瘤闭塞相关的指标。记录动脉瘤流入率 (Q) 和时间平均壁面剪切应力 (TAWSS) 的绝对和相对减少。

结果

发现 eCLIPs 设备以与管状分流器类似的定性方式执行，但与此类设备相比，指标的总体减少程度更为适度。与目前临床使用的类似设备的通用分流器 (FD _BRAIDED )相比，eCLIP 的动脉瘤流入减少和 TAWSS 减少通常低 10-20% 。与这些设备相比，eCLIP 在扩散流入射流和降低整体流速方面效果较差。此结果可能是由于 eCLIP 中的设备孔径较大。值得注意的是，发现 eCLIP 对进出动脉瘤的血流提供了大致相等的阻力，这对于 FD _{BRAIDED而言并非如此}装置，在动脉瘤颈部可以看到高速集中的流出物以及局部 TAWSS 抬高。此处未详细检查此类行为的临床意义，但可能意义重大。

结论

我们的研究结果表明，eCLIPs 装置可作为分叉动脉瘤的分流器，与管状分流器相比，闭塞特性有所减弱，但在子血管中没有与使用传统装置相关的明显滞留和流量减少。