Smith P Alex, De-Sciscio Paul, Sampaio Luiz C, Cohn William E, McMahon Richard A
Annu Int Conf IEEE Eng Med Biol Soc. 2017 Jul;2017:1282-1286. doi: 10.1109/EMBC.2017.8037066.
In the development of a left ventricular assist device (LVAD), it is important to evaluate the LVAD's hemodynamic effect on the compromised left ventricle (LV) before surgical implantation. The mock circulatory loop (MCL) is widely accepted as an in vitro test platform to evaluate LVADs across a wide range of operational conditions as a way to examine how the device and the cardiovascular system interact. Unfortunately, most MCLs represent an oversimplified model of cardiac function, with disease states simulated through generalized changes in heart rate and stroke volume. Because heart failure (HF) severity varies substantially among patients, an MCL is needed that can mimic the pressure-volume loop of an individual patient. In this work, two numerical elastance models, derived from a specific pressure volume loop template, were used to control the LV simulator of the MCL to simulate different degrees of HF. The numerical elastance model was then scaled to change the slopes of the end-systolic (ESPVR) and end-diastolic (EDPVR) pressure volume relationship curves to simulate systolic and diastolic dysfunction. The resulting experimental pressure volume loops are consistent with theoretical loops, demonstrating the feasibility of creating an MCL that can be customized for the patient.
在左心室辅助装置(LVAD)的研发过程中,在手术植入前评估LVAD对受损左心室(LV)的血流动力学效应非常重要。模拟循环回路(MCL)作为一种体外测试平台被广泛接受,用于在各种操作条件下评估LVAD,以此来研究该装置与心血管系统如何相互作用。不幸的是,大多数MCL代表了一种过于简化的心脏功能模型,通过心率和每搏输出量的一般变化来模拟疾病状态。由于心力衰竭(HF)的严重程度在患者之间差异很大,因此需要一个能够模拟个体患者压力-容积环的MCL。在这项工作中,从特定压力-容积环模板导出的两个数值弹性模型被用于控制MCL的LV模拟器,以模拟不同程度的HF。然后对数值弹性模型进行缩放,以改变收缩末期(ESPVR)和舒张末期(EDPVR)压力-容积关系曲线的斜率,从而模拟收缩和舒张功能障碍。由此产生的实验压力-容积环与理论环一致,证明了创建一个可为患者定制的MCL的可行性。