ValVAD: Validation of Controlled Ventricular Assist Devices by Performance and Reliability Analysis in a Hardware-in-the-Loop Test Bench
Final Report Abstract
Heart failure affects a significant number of people worldwide. This is often due to reduced contractility of the left ventricle, which is why the use of left ventricular assist devices (LVADs) has proven to be extremely effective for patients with heart failure. The majority of LVADs currently available on the market operate at a constant pump speed and cannot be adjusted to the physiological state of a patient, which can lead to adverse events or even critical states. Scientific challenges include the measurement system to measure or estimate the physiological state of the patient, the physiological controller of the LVAD, and validation methods for the assisted circulation. Therefore, the aim of this project was to investigate the performance and reliable operation of physiological LVAD controllers with integrated pressure sensors as well as to develop the required test and validation methods. A hybrid mock circulation (HMC) test rig was used to investigate the influence of disturbances and measurement uncertainties of a HeartMate 3 LVAD with an integrated pressure sensor on the performance and robustness for different physiological controllers. It was shown that the system response of these LVAD controllers to disturbances varies in robustness. Thus, there are large differences with respect to the reliable operation of the LVAD. The influence of sensor drift and signal noise on the sensitivity and robustness of the control response to changes in preload and afterload was investigated. The large differences between the controllers highlight the need for system integration testing with the particular combination of sensor, controller and LVAD. It was also shown that a large test space needs to be covered for system integration testing. Seven physiological controllers were tested on two state-of-the-art cardiovascular models using in silico and in vitro studies on an HMC test bench to investigate patient-specific influences on control performance and reliable operation. The choice of the cardiovascular model and its parameters has a strong influence on the performance and robustness characteristics. Therefore, it can be concluded that different cardiovascular models or at least different parameter sets should be used for the validation of LVADs by in silico and in vitro tests. Finally, to increase the reliability of the system, a fail-safe control system was developed. At the HMC, the system was tested in realistic scenarios.
Publications
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Design and Testing of Sensors and Actuators for Advanced Cardiovascular Technologies. Invited lecture at the ESAO-IFAO Webinars 2022–2023: Artificial Organs & Regenerative Medicine: Clinical Challenges, Emerging Technologies, Improved Medical Care, Online, 2023.
T. Gwosch
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P79: Comparison of Cardiovascular Models for Validation of Controlled Ventricular Assist Devices. ASAIO Journal, 69(Supplement 2), 155-155.
Gwosch, Thomas; Magkoutas, Konstantinos & Schmid, Daners Marianne
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Physiological Controllers Based on VAD-Integrated Pressure Sensor: Experimental Validation. Conference Poster at the Gordon Research Conference Assisted Circulation (GRC), Waterville Valley, 2023.
T. Gwosch; K. Magkoutas & M. Schmid Daners
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Physiological Controllers Based on VAD-Integrated Pressure Sensor: Experimental Validation. Conference Presentation at the Gordon Research Seminar Assisted Circulation (GRS), Waterville Valley, 2023.
T. Gwosch; K. Magkoutas & M. Schmid Daners
