通过主动脉幻影进行血液动力学的粒子图像测速
Summary
本方案描述了为研究通过经导管主动脉瓣（TAV）的 体外 设置的窦流而进行的颗粒图像测速（PIV）测量。还确定了基于速度的血流动力学参数。
Abstract
最近有经导管主动脉瓣植入术 （TAVI） 患者主动脉瓣功能障碍和卒中的报道。已怀疑主动脉窦和新窦中由于血流动力学改变而出现血栓。 体外 实验有助于研究 体内 评估证明有限的情况下的血流动力学特征。 体外 实验也更加稳健，可变参数易于控制。粒子图像测速（PIV）是一种用于 体外 研究的流行测速方法。它提供了高分辨率的速度场，因此甚至可以观察到小尺度的流动特征。本研究的目的是展示如何使用PIV来研究TAVI后主动脉窦的流场。描述了主动脉幻象的 体外 设置，用于PIV的TAVI以及数据采集过程和后处理流程分析。推导血流动力学参数，包括速度、流动停滞、涡旋、涡度和颗粒驻留。结果证实， 体外 实验和PIV有助于研究主动脉窦的血流动力学特征。
Introduction
主动脉瓣狭窄是老年人的常见疾病，当主动脉瓣不打开时，会减少血流量。该问题是由主动脉瓣1的增厚或钙化引起的。因此，这是一种必要的治疗方法，可以增强血液流动并减少心脏的负荷。它通过重塑主动脉瓣或用人工瓣膜代替它来治疗。本研究的重点是经导管主动脉瓣植入术（TAVI），使用导管用人工主动脉瓣取代功能异常的主动脉瓣。
TAVI已被推荐用于手术中受到挑战的患者，死亡率也很低2。近日，已有报道，TAVI患者血栓引起瓣膜功能障碍和中风3，4。怀疑主动脉窦和新窦中的血栓，其原因可能是TAVI引起的血流动力学变化。它是在不删除本地传单的情况下执行的;这些小叶会扰乱鼻窦流动并增加血栓形成的风险5。
很难确定TAVI如何影响血流以及如何在患者中诱导血栓形成。希望阐明血流与 体内血栓形成之间的关系。然而，缺乏测量血流的实用技术使这成为问题。另一方面， 体外 技术具有通过限制必须研究的参数来监测血流变化的优点。 体外 设置和颗粒图像测速（PIV）已被用于识别医疗领域的速度6，7，8。因此， 体外 和PIV足以通过模仿患者的病情来确定要报告的参数：心率和压力，粘度和鼻窦几何形状，并允许人们控制这些参数。
在这项研究中， 体外 设置和PIV用于研究TAVI后主动脉窦的血流。该方案描述了PIV的主动脉幻像和TAVI以及数据采集过程和后处理流量分析。推导了各种血流动力学参数，包括速度，静止，涡旋，涡度和颗粒驻留。结果表明， 体外 设置和PIV有助于研究主动脉窦的血流动力学特征。
Protocol
1. 体外 设置 在光学工作台上准备实验装置，包括柱塞泵，数据采集装置（DAQ）以及具有所需系统工程软件和电机控制软件的计算机（见 材料表）（图1）。注：柱塞泵先前已经过测试和校准，由电机、电机驱动器和线性执行器9组成。 将包含流速信息的电子表格文件导入系统工程软件。注意：例如，心?…
Representative Results
速度场根据 图4中的阀门直径显示出不同的正弦流结构。对于TAV（23 mm），TAV和STJ之间的速度高于0.05 m / s，从早期收缩到使用转发射流打开的TAV峰值收缩。然后将高速分布在收缩期晚期支架附近的狭窄范围内。舒张期速度低于0.025 m/s，出现2个低速涡流。对于TAV（26毫米），当阀门打开时，在STJ处测量高速。除早期收缩外，鼻窦速度分布均低于0.05 m/s。具体而言，收缩晚期的速…
Discussion
由于TAVI后窦的几何形状不同，窦流发生了变化。漩涡是由主动脉瓣打开和与收缩素22的前射流的相互作用形成的。在没有天然小叶的人工手术瓣膜的研究中，在收缩期在窦区观察到的涡旋正常23。该研究通过减少前射流并进入鼻窦来形成舒张时呈现的涡旋。窦流遇到本地小叶;结果，它在本地小叶下方顺时针拆分，在上方逆时针拆分。这表明TAVI后的患者与没有血…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
本研究由韩国国家研究基金会基础科学研究计划支持，该计划由教育部资助（NRF-2021R1I1A3040346和NRF-2020R1A4A1019475）。这项研究还得到了江原国立大学2018年研究资助（PoINT）的支持。
Materials
| 3D Printer | Prusa Research | Original Prusa i3 MK2; FDM printer | |
| Aluminum bar (square) | APSPRO | KHP-3030, KHP-6060 | Dimension: 30 mm x 30 mm, 60 mm x 60 mm |
| Bulb pump | Skyhope | MHL-1 | |
| Camera controlling software | Phantom | PCC 3.4 software | The software controll the high speed camera |
| Check valve | HANJU STEEL PIPE | Check valve; 1/2 inch (15A) | |
| Digital Aqusition device | National Instruments | USB-6001 | |
| Glycerin | ANU Korea | It used for making a working fluid | |
| High-speed camera | Phantom | Phantom VEO 710E-L | |
| Laser | Changchun New Industries Optoelectronics Technology | MGL-W-532; CW Nd:YAG Laser | |
| Linear actuator | THOMSON | PC-40; it converts the rotational motion to lenear motion | |
| Macro lens | Nikon | VR Micro-NIKKOR 105mm, f/1.4 | |
| Motor | KOLLMORGEN | AKM33H-ANCNR-00; DC servo motor | |
| Motor controlling software | KOLLMORGEN | Kollmorgen software; the software controll the motor driver | |
| Motor driver | KOLLMORGEN | AKD-B00606-NBAN-0000 | |
| Open-source electronic prototypic platform | Arduino | A000066 | Arduino Uno R3. It used for making a external trigger |
| Optic table | SMTECH | 1800 (W) x 900 (B) x 800 (H) | |
| Particle | Dantec Dynamics | 80A6011 | Hollow Glass Sphere. Mean diameter:10 µm, Density: 1090 kg/m3 |
| PIVlab | PIVlab | Open source algorithm based on MATLAB https://kr.mathworks.com/matlabcentral/fileexchange/27659-pivlab-particle-image-velocimetry-piv-tool-with-gui |
|
| Pressure gauge | OMEGA | PX309-015A5V. Measurement range: 0~15psi | |
| Refractometer | ATAGO | 2350 | R-5000. Hand held refractometer; measurement range: 1.333-1.520 |
| Resistance valve | HANJU STEEL PIPE | Ball valve; 1/2 inch (15A) | |
| Saline | DAI HAN PHARM | It is used for making a working fluid and for preserving the TAV | |
| Silicone hose | HSW | Inner diameter 26mm, Outter diameter 30mm; Inlet length 5m, Outlet length 1.5m | |
| System enginnering software | National Instruments | LabVIEW software. The software controlls the DAQ. | |
| Transcatheter Aortic Valve, TAV (23 mm) and TAV (26 mm) | Edwards Lifesciences | SAPIEN3 23mm, SAPIEN3 26mm. It is supported by Seoul Asan Medical | |
| Viscosmeter | Brookfiled | DVELV; Measurement range: 1-2×109 cp |
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Citazione di questo articolo
Kang, J., Ha, H. Particle Image Velocimetry Investigation of Hemodynamics via Aortic Phantom. J. Vis. Exp. (180), e63492, doi:10.3791/63492 (2022).