Institute of Biomechanics, Graz University of Technology, Graz, Austria.
Institute of Automation and Control, Graz University of Technology, Graz, Austria.
Artif Organs. 2021 Dec;45(12):1562-1575. doi: 10.1111/aor.14064. Epub 2021 Sep 25.
Arterial compliance assists the cardiovascular system with three key roles: (i) storing up to 50% of the stroke volume; (ii) ensuring blood flow during diastole; (iii) dampening pressure oscillations through arterial distension. In mock circulation loops (MCLs), arterial compliance was simulated either with membrane, spring, or Windkessel chambers. Although they have been shown to be suitable for cardiac device testing, their passive behavior can limit stress-based testing of arteries. Here we present an active compliance chamber with a feedback control of variable compliance as part of an MCL designed for biomechanical evaluation of arteries under physiological waveforms.
The chamber encloses a piston that changes the volume via a cascaded controller when there is a difference between the real-time pressure and the physiological reference pressure with the aim to equilibrate both pressures.
The experimental results showed repeatable physiological waveforms of aortic pressure in health (80-120 mm Hg), systemic hypertension (90-153 mm Hg), and heart failure reduced ejection fraction (78-108 mm Hg). Statistical validation (n = 20) of the function of the chamber is presented against compared raw data.
We demonstrate that the active compliance chamber can track the actual pressure of the MCL and balance it in real time (every millisecond) with the reference values in order to shape the given pressure waveform. The active compliance chamber is an advanced tool for MCL applications for biomechanical examination of stented arteries and for preclinical evaluation of vascular implants.
动脉顺应性有助于心血管系统发挥三个关键作用：（i）储存高达 50%的搏出量；（ii）确保舒张期的血流；（iii）通过动脉扩张缓冲压力波动。在模拟循环回路（MCL）中，动脉顺应性可以通过膜、弹簧或风箱腔来模拟。尽管它们已被证明适用于心脏设备测试，但它们的被动行为可能会限制基于压力的动脉测试。在这里，我们提出了一种具有可变顺应性反馈控制的主动顺应性室，作为 MCL 的一部分，旨在设计用于在生理波形下对动脉进行生物力学评估。
该腔室包围一个活塞，当实时压力与生理参考压力之间存在差异时，通过级联控制器改变活塞的体积，目的是使两种压力平衡。
实验结果显示，在健康状态（80-120mmHg）、全身性高血压（90-153mmHg）和射血分数降低的心力衰竭（78-108mmHg）下，主动脉压力呈现出可重复的生理波形。对腔室功能进行了统计学验证（n=20），并与原始数据进行了比较。
我们证明主动顺应性室可以跟踪 MCL 的实际压力，并实时（每毫秒）与参考值平衡，以形成给定的压力波形。主动顺应性室是用于生物力学检查支架动脉和血管植入物临床前评估的 MCL 应用的先进工具。
