Hemodynamic characterization of the Realheart® total artificial heart with a hybrid cardiovascular simulator

Fresiello, Libera; Najar, Azad; Ignell, Nils Brynedal; Zieliński, Krzysztof; Rocchi, Maria; Meyns, Bart; Perkins, Ina Laura

doi:10.1111/aor.14223

Cited by 9 publications

(17 citation statements)

References 24 publications

(51 reference statements)

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“…A hybrid cardiovascular simulator was adapted to test and characterize the hemodynamic behavior of the Realheart TAH, and the study was previously reported. 41 Briefly, the hybrid simulator was comprised of a computational and a hydraulic component: the computational domain was a lumped parameter model of the cardiovascular system; the hydraulic domain included four "hybrid interfaces" where the TAH was connected to interact with the rest of the circulation. Pressure sensors (PPG Honeywell, Columbus, OH, USA) measured the pressure in the hydraulic chambers mimicking the aorta and the left atrium.…”

Section: Hybrid Rig Experimentsmentioning

confidence: 99%

Video‐based valve motion combined with computational fluid dynamics gives stable and accurate simulations of blood flow in the Realheart total artificial heart

et al. 2021

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Background: Patients with end-stage, biventricular heart failure, and for whom heart transplantation is not an option, may be given a Total Artificial Heart (TAH). The Realheart® is a novel TAH which pumps blood by mimicking the native heart with translation of an atrioventricular plane. The aim of this work was to create a strategy for using Computational Fluid Dynamics (CFD) to simulate haemodynamics in the Realheart®, including motion of the atrioventricular plane and valves. Methods:The accuracies of four different computational methods for simulating fluid-structure interaction of the prosthetic valves were assessed by comparison of chamber pressures and flow rates with experimental measurements.The four strategies were: prescribed motion of valves opening and closing at the atrioventricular plane extrema; simulation of fluid-structure interaction of both valves; prescribed motion of the mitral valve with simulation of fluid-structure interaction of the aortic valve; motion of both valves prescribed from video analysis of experiments. Results:The most accurate strategy (error in ventricular pressure of 6%, error in flow rate of 5%) used video-prescribed motion. With the Realheart operating at 80 bpm, the power consumption was 1.03 W, maximum shear stress was 15 Pa, and washout of the ventricle chamber after 4 cycles was 87%. Conclusions:This study, the first CFD analysis of this novel TAH, demonstrates that good agreement between computational and experimental data can be achieved. This method will therefore enable future optimisation of the geometry and motion of the Realheart®.

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Section: Hybrid Rig Experimentsmentioning

confidence: 99%

Video‐based valve motion combined with computational fluid dynamics gives stable and accurate simulations of blood flow in the Realheart total artificial heart

et al. 2021

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“…A hybrid cardiovascular simulator, comprised of a lumped parameter computational domain that modelled the cardiovascular system and a physical hydraulic component featuring flow chambers, was adapted and connected to the Realheart TAH to form a loop, and the haemodynamic response of the device under physiologically realistic conditions was measured 22 . A pressure sensor (PPG Honeywell, Columbus, OH, USA) measured the left aortic pressure just downstream of the aortic valve, and a Transonic flow meter (ME24 PXN, T402 Transonic Systems Inc, Ithaca, NY, USA) measured the left outflow flow rates.…”

Section: Methodsmentioning

confidence: 99%

“…In the hybrid cardiovascular simulator, impedance values were set to a compliance ml/mmHg and a resistance Wood Units 22 . For the FSI simulation, the impedance parameters were the same as the experimental values, with the exception that the compliance was increased by an additional 0.2 ml/mmHg to account for parasitic compliances within the mechanical components of the hybrid cardiovascular simulator.…”

Section: Methodsmentioning

confidence: 99%

“…The Cleveland Clinic CFTAH (Cleveland Clinic, Cleveland OH, USA) and the BiVACOR TAH (BiVACOR, Houston TX, USA) are both rotary TAHs that provide both systemic and pulmonary flow using a single moving rotor suspended by a hydrodynamic and maglev bearings respectively 11 , 12 . The Realheart TAH (Scandinavian Real Heart, Västerås, Sweden) is a novel four-chamber, two-sided pump that can deliver upwards of 7 L/min, and mimics the mechanics of the native heart by translating the atrioventricular (AV) plane to produce pulsatile flow, the direction of which is governed by a pair of bileaflet mechanical heart valves (BMHVs) 10 , 22 .…”

Section: Introductionmentioning

confidence: 99%

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Fluid–structure interaction modelling of a positive-displacement Total Artificial Heart

Bornoff

Najar²,

Fresiello

et al. 2023

Sci Rep

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For those suffering from end-stage biventricular heart failure, and where a heart transplantation is not a viable option, a Total Artificial Heart (TAH) can be used as a bridge to transplant device. The Realheart TAH is a four-chamber artificial heart that uses a positive-displacement pumping technique mimicking the native heart to produce pulsatile flow governed by a pair of bileaflet mechanical heart valves. The aim of this work was to create a method for simulating haemodynamics in positive-displacement blood pumps, using computational fluid dynamics with fluid–structure interaction to eliminate the need for pre-existing in vitro valve motion data, and then use it to investigate the performance of the Realheart TAH across a range of operating conditions. The device was simulated in Ansys Fluent for five cycles at pumping rates of 60, 80, 100 and 120 bpm and at stroke lengths of 19, 21, 23 and 25 mm. The moving components of the device were discretised using an overset meshing approach, a novel blended weak–strong coupling algorithm was used between fluid and structural solvers, and a custom variable time stepping scheme was used to maximise computational efficiency and accuracy. A two-element Windkessel model approximated a physiological pressure response at the outlet. The transient outflow volume flow rate and pressure results were compared against in vitro experiments using a hybrid cardiovascular simulator and showed good agreement, with maximum root mean square errors of 15% and 5% for the flow rates and pressures respectively. Ventricular washout was simulated and showed an increase as cardiac output increased, with a maximum value of 89% after four cycles at 120 bpm 25 mm. Shear stress distribution over time was also measured, showing that no more than $$4.5\times 10^{-4}$$ 4.5 × 10 - 4 % of the total volume exceeded 150 Pa at a cardiac output of 7 L/min. This study showed this model to be both accurate and robust across a wide range of operating points, and will enable fast and effective future studies to be undertaken on current and future generations of the Realheart TAH.

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“…Within this project, the HCVS coupled with other tools developed by other consortium partners was a part of the information and communication system. The control algorithm of the left ventricular rotary CircuLite synergy micro pump (HeartWare, Framingham, MA, USA) was studied by means of this system [62].…”

Section: Appendix Amentioning

confidence: 99%

Virtual and Artificial Cardiorespiratory Patients in Medicine and Biomedical Engineering

et al. 2022

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Recently, ‘medicine in silico’ has been strongly encouraged due to ethical and legal limitations related to animal experiments and investigations conducted on patients. Computer models, particularly the very complex ones (virtual patients—VP), can be used in medical education and biomedical research as well as in clinical applications. Simpler patient-specific models may aid medical procedures. However, computer models are unfit for medical devices testing. Hybrid (i.e., numerical–physical) models do not have this disadvantage. In this review, the chosen approach to the cardiovascular system and/or respiratory system modeling was discussed with particular emphasis given to the hybrid cardiopulmonary simulator (the artificial patient), that was elaborated by the authors. The VP is useful in the education of forced spirometry, investigations of cardiopulmonary interactions (including gas exchange) and its influence on pulmonary resistance during artificial ventilation, and explanation of phenomena observed during thoracentesis. The artificial patient is useful, inter alia, in staff training and education, investigations of cardiorespiratory support and the testing of several medical devices, such as ventricular assist devices and a membrane-based artificial heart.

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Hemodynamic characterization of the Realheart® total artificial heart with a hybrid cardiovascular simulator

Cited by 9 publications

References 24 publications

Video‐based valve motion combined with computational fluid dynamics gives stable and accurate simulations of blood flow in the Realheart total artificial heart

Video‐based valve motion combined with computational fluid dynamics gives stable and accurate simulations of blood flow in the Realheart total artificial heart

Fluid–structure interaction modelling of a positive-displacement Total Artificial Heart

Virtual and Artificial Cardiorespiratory Patients in Medicine and Biomedical Engineering

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