Purpose

The Frozen Elephant Trunk (FET) stent is a hybrid endovascular device that may be implemented in the event of an aneurysm or aortic dissection of the aortic arch or superior descending aorta. A Type 1B endoleak can lead to intrasaccular flow during systole and has been identified as a known failure of the FET stent graft. The purpose was to develop in-vitro modelling techniques to enable the investigation of the known failure.

Methods

A silicone aortic phantom and 3D printed surrogate stent graft were manufactured to investigate the haemodynamics of a Type 1B endoleak. Physiological pulsatile flow dynamics distal to the surrogate stent graft were investigated in-vitro using Particle Image Velocimetry (PIV).

Results

PIV captured recirculation zones and an endoleak distal to the surrogate stent graft. The endoleak was developed at the peak of systole and sustained until the onset of diastole. The endoleak was asymmetric, indicating a potential variation in the phantom artery wall thickness or stent alignment. Recirculation was identified on the posterior dorsal line during late systole.

Conclusions

The identification of the Type 1B endoleak proved that in-vitro modelling can be used to investigate complex compliance changes and wall motions. The recirculation may indicate the potential for long term intimal layer inflammatory issues such as atherosclerosis. These results may aid future remediation techniques or stent design. Further development of the methods used in this experiment may assist with the future testing of stents prior to animal or human trial.

中文翻译：

---

冷冻象鼻支架替代物远端血流动力学的 PIV 分析

目的

Frozen Elephant Trunk (FET) 支架是一种混合血管内装置，可在主动脉弓或上降主动脉发生动脉瘤或主动脉夹层的情况下实施。1B 型内漏可在收缩期导致囊内血流，已被确定为 FET 覆膜支架的已知故障。目的是开发体外建模技术，以便对已知故障进行调查。

方法

制造了一个硅胶主动脉模型和 3D 打印的替代支架移植物，以研究 1B 型内漏的血液动力学。使用粒子图像测速法 (PIV)在体外研究了替代支架移植物远端的生理脉动流动力学。

结果

PIV 捕获了再循环区和替代支架移植物远端的内漏。内漏发生在收缩期峰值并持续到舒张期开始。内漏是不对称的，表明幻影动脉壁厚度或支架排列的潜在变化。在收缩晚期期间在后背线上确定了再循环。

结论

1B 型内漏的鉴定证明体外建模可用于研究复杂的顺应性变化和壁运动。再循环可能表明存在长期内膜层炎症问题，例如动脉粥样硬化。这些结果可能有助于未来的修复技术或支架设计。本实验中使用的方法的进一步发展可能有助于未来在动物或人体试验之前对支架进行测试。