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

Abstract

The Virtual Mock Loop (VML) is a mathematical model designed to simulate mechanism of the human cardiovascular system interacting with mechanical circulatory support devices. Here, we aimed to mimic the hemodynamic performance of Cleveland Clinic’s self‐regulating continuous‐flow total artificial heart (CFTAH) via VML and evaluate the accuracy of the VML compared with an in vivo acute animal study. The VML reproduced 124 hemodynamic conditions from three acute in vivo experiments in calves. Systemic/pulmonary vascular resistances, pump rotational speed, pulsatility, and pulse rate were set for the VML from in vivo data. We compared outputs (pump flow, left and right pump pressure rises, and atrial pressure difference) between the two systems. The pump performance curves all fell in the designed range. There was a strong correlation between the VML and the in vivo study in the left pump flow (r2 = 0.84) and pressure rise (r2 = 0.80), and a moderate correlation in right pressure rise (r2 = 0.52) and atrial pressure difference (r2 = 0.59). Although there is room for improvement in simulating right‐sided pump performance of self‐regulating CFTAH, the VML acceptably simulated the hemodynamics observed in an in vivo study. These results indicate that pump flow and pressure rise can be estimated from vascular resistances and pump settings.

The ongoing quest for the first total artificial heart as destination therapy

“…Many TAH developers have used continuous-flow pump technology to develop custom-built TAH devices. Several continuous-flow TAHs are currently under development: BiVACOR (BiVACOR, Houston, TX, USA) 95 , Cleveland continuous-flow TAH (CFTAH) 96,97 and helical-flow TAH (HFTAH) (University of Tokyo, Tokyo, Japan) 98 are being assessed in chronic animal experiments, and Hybrid CFTAH (Drexel University, Philadelphia, PA, USA) 99 and OregonHeart (OregonHeart, Portland, OR, USA) 100,101 are undergoing in vitro testing.…”

Balancing the ventricular outputs of pulsatile total artificial hearts

“…For more than half a century, several TAHs have been developed. Currently, two TAHs: SynCardia (SynCardia Systems, Tucson, AZ, USA) 3,4 and Carmat (Aeson; Carmat, Vélizy‐Villacoublay, France) 5,6 are approved for clinical use, and many other TAHs are under development 7–10 …”

“…Currently, two TAHs: SynCardia (SynCardia Systems, Tucson, AZ, USA) 3,4 and Carmat (Aeson; Carmat, Vélizy-Villacoublay, France) 5,6 are approved for clinical use, and many other TAHs are under development. [7][8][9][10] Achieving and maintaining a balance between the left and right ventricular outputs is a major hurdle that has to be overcome when developing a TAH. A TAH has to continuously adapt its cardiac outputs to changing hemodynamic conditions.…”