Chitsaz Alireza, Nejat Amir, Nouri Reza
School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
Artif Organs. 2018 Dec;42(12):E406-E419. doi: 10.1111/aor.13300. Epub 2018 Nov 15.
Acute ischemic stroke (AIS) is the leading cause of mortality and disability worldwide. AIS occur while cerebral arteries become blocked by embolism or thrombosis. Aspiration thrombectomy is a promising interventional device to extract massive clots from occluded cerebral arteries. The aim of this article is to develop a computer-aided method to clarify the performance of aspiration catheter and identify the risks of aspiration for each specific AIS patient. In order to simulate the aspiration process, a three-dimensional fluid-structure interaction (FSI) method was developed. The blood clot was modeled as a porous media which composed of viscoelastic fibrin networks. The finite element method (FEM) was implemented to compute the blood flow dynamics in the simplified cerebral vessel. The introduced clot model was validated by comparing the numerical results with experimental data. Furthermore, the analytical solution of the flow through the partially porous pipe was considered to validate FEM. In this research, the performance of two model of the Penumbra aspiration catheter-4MAX and 5MAX-were were compared at three distinct suction pressures. The aspiration ratio of the clot, aspiration time, amount of free fragments, wall shear stress (WSS), and extracted volume of the blood were calculated to evaluate catheters performance. At suction pressure -50 kPa, the aspiration ratio of 5MAX catheter reached 86.58% within 1.36 s. However, in 4MAX case, aspiration ratio of 76.41% was achieved within 1.39. Also, 5MAX catheter created 6.11% fewer free fragments in comparison to 4MAX. Hence, the possibility of distal embolization of 4MAX model was greater. However, the risk of vessel wall rupture was higher in 5MAX by considering mean WSS.
急性缺血性中风（AIS）是全球范围内导致死亡和残疾的主要原因。AIS发生于脑动脉被栓塞或血栓阻塞之时。抽吸血栓切除术是一种有前景的介入设备，用于从阻塞的脑动脉中取出大量血栓。本文的目的是开发一种计算机辅助方法，以阐明抽吸导管的性能，并识别每个特定AIS患者的抽吸风险。为了模拟抽吸过程，开发了一种三维流固相互作用（FSI）方法。血凝块被建模为由粘弹性纤维蛋白网络组成的多孔介质。采用有限元方法（FEM）计算简化脑血管中的血流动力学。通过将数值结果与实验数据进行比较，对引入的血凝块模型进行了验证。此外，考虑了通过部分多孔管道的流动的解析解以验证有限元方法。在本研究中，比较了Penumbra抽吸导管的两种型号——4MAX和5MAX——在三种不同抽吸压力下的性能。计算血凝块的抽吸率、抽吸时间、游离碎片量、壁面剪应力（WSS）和血液抽出量，以评估导管性能。在抽吸压力为-50 kPa时，5MAX导管的抽吸率在1.36秒内达到86.58%。然而，在4MAX的情况下，在1.39秒内达到了76.41%的抽吸率。此外，与4MAX相比，5MAX导管产生的游离碎片减少了6.11%。因此，4MAX型号发生远端栓塞的可能性更大。然而，考虑平均壁面剪应力时，5MAX导致血管壁破裂的风险更高。
