Use of a Mechanical Circulatory Support Simulation to Study Pump Interactions With the Variable Hemodynamic Environment

Abstract

The Virtual Mock Loop, a versatile virtual mock circulation loop, was developed using a lumpedparameter model of the mechanically assisted human circulatory system. Inputs allow specification of a variety of continuous-flow pumps (left, right, or biventricular assist devices) and a total artificial heart that can selfregulate between left and right pump outputs. Hemodynamic inputs were simplified using a diseasebased input panel, allowing selection of a combination of cardiovascular disease states, including systolic and diastolic heart failure, stenosis, and/or regurgitation in each of the four valves, and high to low systemic and pulmonary vascular resistance values. The menu-driven output includes a summary of hemodynamic parameters and graphical output of selected flows, pressures, and volumes in the heart's four chambers as well as in the pulmonary artery and aorta.New tools to augment experimental research on implantable heart-assist devices and to increase our understanding of patient-specific pump interactions are in high demand. The purpose of this ongoing study is to demonstrate the use of a system analysis computer simulation to explore and better comprehend the interactions of mechanical circulatory support (MCS) pumps with a more extensive combination of patientspecific or simulation conditions than can be established by practical experimentation. Usability is an important factor in constructing computer models for research purposes, and among our primary objectives in creating this simulation model were to make it as portable and useful as possible outside the lab environment, by people not involved in the creation of its operational software.

Analysis of Cleveland Clinic continuous‐flow total artificial heart performance using the Virtual Mock Loop: Comparison with an in vivo study

“…The VML software, developed in MATLAB (MathWorks, Inc., Natick, MA, USA), simulates the hemodynamics of the cardiovascular system with a lumped‐parameter model, including systemic and pulmonary circulation and cardiac four‐chamber and valve characteristics . In this study, we developed a new version of the VML specialized to simulate a CFTAH support condition (Figure ).…”

“…The VML software, developed in MATLAB (MathWorks, Inc., Natick, MA, USA), simulates the hemodynamics of the cardiovascular system with a lumped-parameter model, including systemic and pulmonary circulation and cardiac four-chamber and valve characteristics. 12 In this study, we developed a new version of the VML specialized to simulate a CFTAH support condition ( Figure 2). The development of this new model included removing the input for heart condition, as both ventricles with four valves are resected during implantation, and including the speed modulation feature of the CFTAH, adding both pulse rate and speed range, as the CFTAH is able to run with sinusoidal speed modulation.…”

“…At our institution, we have developed the original numerical simulation model, called the Virtual Mock Loop (VML), to support the development of MCS devices and other modalities. The VML has characteristic features that allow it to simulate the performance of LVADs, RVADs, TAHs, and various types of heart failure conditions . We have previously reported the simulation results of our CFTAH with the VML, and the reliability of the numerical model was compared to bench testing .…”

“…The VML has characteristic features that allow it to simulate the performance of LVADs, RVADs, TAHs, and various types of heart failure conditions. 12 We have previously reported the simulation results of our CFTAH with the VML, and the reliability of the numerical model was compared to bench testing. 13 In that study, the VML successfully reproduced results from the mock circulatory loop of CFTAH test conditions and the CFTAH's self-regulation of right-pump performance was also calculated effectively.…”

Artificial Organs 2018: A Year in Review

“…David J. Horvath et al of R1 Engineering, Euclid, OH, USA, reported on their virtual mock circulation loop to better comprehend the interactions of mechanical circulatory support pumps with more extensive combination of patient‐specific or simulation conditions than can be established by practical experimentation. Usability was an important factor in constructing computer models for research purposes, and among their primary objectives in creating this simulation model were to make it as portable and useful as possible outside the lab environment, by people not involved in the creation of its operational software.…”