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Gwosch T, Magkoutas K, Kaiser D, Schmid Daners M. Performance and Reliable Operation of Physiological Controllers Under Various Cardiovascular Models: In Silico and In Vitro Study. ASAIO J 2024; 70:485-494. [PMID: 38373197 DOI: 10.1097/mat.0000000000002143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
The evaluation of control schemes for left ventricular assist devices (LVADs) requires the utilization of an appropriate model of the human cardiovascular system. Given that different patients and experimental data yield varying performance of the cardiovascular models (CVMs) and their respective parameters, it becomes crucial to assess the reliable operation of controllers. This study aims to assess the performance and reliability of various LVAD controllers using two state-of-the-art CVMs, with a specific focus on the impact of interpatient variability. Extreme test cases were employed for evaluation, incorporating both in silico and in vitro experiments. The differences observed in response between the studied CVMs can be attributed to variations in their structures and parameters. Specifically, the model with smaller compartments exhibits higher overload rates, whereas the other model demonstrates increased sensitivity to changes in preload and afterload, resulting in more frequent suction events (34.2% vs. 8.5% for constant speed mode). These findings along with the varying response of the tested controllers highlight the influence of the selected CVM emphasizing the need to test each LVAD controller with multiple CVMs or, at least, a range of parameter sets. This approach ensures sufficient evaluation of the controller's efficacy in addressing interpatient variability.
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Affiliation(s)
- Thomas Gwosch
- From the Product Development Group Zurich, ETH Zurich, Zurich, Switzerland
| | | | - David Kaiser
- From the Product Development Group Zurich, ETH Zurich, Zurich, Switzerland
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Schlöglhofer T, Gross C, Moscato F, Neumayer A, Kandioler E, Leithner D, Skoumal M, Laufer G, Wiedemann D, Schima H, Zimpfer D, Marko C. Exercise Performance and Quality of Life of Left Ventricular Assist Device Patients After Long-Term Outpatient Cardiac Rehabilitation. J Cardiopulm Rehabil Prev 2023; 43:346-353. [PMID: 37014949 DOI: 10.1097/hcr.0000000000000789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
PURPOSE Exercise performance and quality of life (QoL) of left ventricular assist device (LVAD) patients improve after early cardiac rehabilitation (CR). The purpose of this study was to examine the efficacy of multiprofessional long term phase 3 outpatient CR, and whether cardiopulmonary exercise testing (CPX) and 6-min walk testing (6MWT) post-LVAD implantation predict hospital readmission. METHODS This retrospective observational cohort study included 29 LVAD patients (58.6 ± 7.7 yr, female: 13.8%, body mass index: 29.4 ± 3.3 kg/m 2 ). Functional performance tests (CPX, 6MWT, sit-to-stand test), QoL, and psychological surveys (Kansas City Cardiomyopathy Questionnaire, hospital anxiety and depression scale, and Control Convictions about Disease and Health [KKG]) were performed at baseline and at the end of CR. RESULTS The CR was initiated at a median (IQR) of 159 (130-260) d after LVAD implantation for a duration of 340 (180-363) d with 46.8 ± 23.2 trainings. The 6MWT (408.4 ± 113.3 vs 455.4 ± 115.5 m, P = .003) and sit-to-stand test (16.7 ± 6.9 vs 19.0 ± 5.3 repetitions, P = .033) improved, but relative peak oxygen uptake (V˙ o2peak : 9.4 [8.2-14.4] vs 9.3 [7.8-13.4] mL/min/kg, P = .57) did not change. Using receiver operating characteristic curve analysis, baseline V˙ o2peak values were associated with readmission 1-yr after CR onset (C-statistic = 0.88) with a cutoff value of V˙ o2peak < 9.15 mL/min/kg (100% sensitivity, 78% specificity, P < .001). The Kansas City Cardiomyopathy Questionnaire self-efficacy and knowledge (+6.3 points), QoL (+5.0 points), and social limitation (+7.1 points) demonstrated clinically important changes. In addition, the hospital anxiety and depression scale showed a significant reduction in anxiety (4.6 ± 3.2 vs 2.6 ± 2.4, P = .03). CONCLUSIONS Long-term CR is safe and LVAD outpatients showed improvement of QoL, anxiety, and submaximal exercise performance. In addition, V˙ o2peak and 6MWT have prognostic value for readmission.
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Affiliation(s)
- Thomas Schlöglhofer
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria (Messrs Schlöglhofer and Neumayer and Drs Gross, Laufer, Wiedemann, Schima, Zimpfer, and Marko); Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria (Messrs Schlöglhofer and Neumayer and Drs Moscato, Schima, and Zimpfer); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria (Mr Schlöglhofer and Drs Moscato and Schima); Austrian Cluster for Tissue Regeneration, Vienna, Austria (Dr Moscato); and Center for Outpatient Rehabilitation Vienna, Vienna, Austria (Drs Kandioler and Skoumal and Ms Leithner)
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(Physiology of Continuous-flow Left Ventricular Assist Device Therapy. Translation of the document prepared by the Czech Society of Cardiology). COR ET VASA 2022. [DOI: 10.33678/cor.2022.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Berardi C, Bravo CA, Li S, Khorsandi M, Keenan JE, Auld J, Rockom S, Beckman JA, Mahr C. The History of Durable Left Ventricular Assist Devices and Comparison of Outcomes: HeartWare, HeartMate II, HeartMate 3, and the Future of Mechanical Circulatory Support. J Clin Med 2022; 11:2022. [PMID: 35407630 PMCID: PMC9000165 DOI: 10.3390/jcm11072022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/25/2022] [Accepted: 03/31/2022] [Indexed: 12/13/2022] Open
Abstract
The utilization of left ventricular assist devices (LVADs) in end-stage heart failure has doubled in the past ten years and is bound to continue to increase. Since the first of these devices was approved in 1994, the technology has changed tremendously, and so has the medical and surgical management of these patients. In this review, we discuss the history of LVADs, evaluating survival and complications over time. We also aim to discuss practical aspects of the medical and surgical management of LVAD patients and future directions for outcome improvement in this population.
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Affiliation(s)
- Cecilia Berardi
- Division of Cardiovascular Medicine, Baystate Medical Center, Springfield, MA 01199, USA;
| | - Claudio A. Bravo
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; (C.A.B.); (S.L.); (J.A.); (S.R.); (J.A.B.)
| | - Song Li
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; (C.A.B.); (S.L.); (J.A.); (S.R.); (J.A.B.)
| | - Maziar Khorsandi
- Division of Cardiothoracic Surgery, Department of Surgery, University of Washington, Seattle, WA 98195, USA; (M.K.); (J.E.K.)
| | - Jeffrey E. Keenan
- Division of Cardiothoracic Surgery, Department of Surgery, University of Washington, Seattle, WA 98195, USA; (M.K.); (J.E.K.)
| | - Jonathan Auld
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; (C.A.B.); (S.L.); (J.A.); (S.R.); (J.A.B.)
| | - Sunny Rockom
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; (C.A.B.); (S.L.); (J.A.); (S.R.); (J.A.B.)
| | - Jennifer A. Beckman
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; (C.A.B.); (S.L.); (J.A.); (S.R.); (J.A.B.)
| | - Claudius Mahr
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; (C.A.B.); (S.L.); (J.A.); (S.R.); (J.A.B.)
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Stapor M, Pilat A, Gackowski A, Misiuda A, Gorkiewicz-Kot I, Kaleta M, Kleczynski P, Zmudka K, Legutko J, Kapelak B, Wierzbicki K. Echo-guided left ventricular assist device speed optimisation for exercise maximisation. Heart 2022; 108:1055-1062. [PMID: 35314453 PMCID: PMC9209671 DOI: 10.1136/heartjnl-2021-320495] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/24/2022] [Indexed: 11/29/2022] Open
Abstract
Objective Current generation left ventricular assist devices (LVADs) operate with a fixed rotation speed and no automated speed adjustment function. This study evaluates the concept of physiological pump speed optimisation based on aortic valve opening (AVO) imaging during a cardiopulmonary exercise test (CPET). Methods This prospective crossover study (NCT05063006) enrolled patients with implanted third-generation LVADs with hydrodynamic bearing. After resting speed optimisation, patients were randomised to a fixed-modified speed or modified-fixed speed CPET sequence. Fixed speed CPET maintained baseline pump settings. During the modified speed CPET, the LVAD speed was continuously altered to preserve periodic AVO. Results We included 22 patients, the mean age was 58.4±7 years, 4.5% were women and 54.5% had ischaemic cardiomyopathy. Exertional AVO assessment was feasible in all subjects. Maintaining periodic AVO allowed to safely raise the pump speed from 2900 (IQR 2640–3000) to 3440 revolutions per minute (RPM) (IQR 3100–3700; p<0.001). As a result, peak oxygen consumption increased from 11.1±2.4 to 12.8±2.8 mL/kg/min (p<0.001) and maximum workload from 1.1 (IQR 0.9–1.5) to 1.2 W/kg (IQR 0.9–1.7; p=0.028). The Borg scale exertion level decreased from 15.2±1.5 to 13.5±1.2 (p=0.005). Conclusions Transthoracic AVO imaging is possible during CPETs in patients with LVAD. Dynamic echo-guided pump speed adjustment based on the AVO improves exercise tolerance and augments peak oxygen consumption and maximum workload.
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Affiliation(s)
- Maciej Stapor
- Department of Interventional Cardiology, John Paul II Hospital, Krakow, Malopolska, Poland
| | - Adam Pilat
- Department of Automatic Control and Robotics, AGH University of Science and Technology, Krakow, Poland
| | - Andrzej Gackowski
- Department of Coronary Disease and Heart Failure, Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Krakow, Poland
| | - Agnieszka Misiuda
- Noninvasive Cardiovascular Laboratory, John Paul II Hospital, Krakow, Poland
| | - Izabela Gorkiewicz-Kot
- Department of Cardiovascular Surgery and Transplantology, John Paul II Hospital, Krakow, Poland
| | - Michal Kaleta
- Department of Cardiovascular Surgery and Transplantology, John Paul II Hospital, Krakow, Poland
| | - Pawel Kleczynski
- Department of Interventional Cardiology, Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Krakow, Poland
| | - Krzysztof Zmudka
- Department of Interventional Cardiology, Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Krakow, Poland
| | - Jacek Legutko
- Department of Interventional Cardiology, Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Krakow, Poland
| | - Boguslaw Kapelak
- Department of Cardiovascular Surgery and Transplantology, Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Krakow, Poland
| | - Karol Wierzbicki
- Department of Cardiovascular Surgery and Transplantology, Jagiellonian University Medical College, Faculty of Medicine, Institute of Cardiology, Krakow, Poland
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Rosenbaum AN, Antaki JF, Behfar A, Villavicencio MA, Stulak J, Kushwaha SS. Physiology of Continuous-Flow Left Ventricular Assist Device Therapy. Compr Physiol 2021; 12:2731-2767. [PMID: 34964115 DOI: 10.1002/cphy.c210016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The expanding use of continuous-flow left ventricular assist devices (CF-LVADs) for end-stage heart failure warrants familiarity with the physiologic interaction of the device with the native circulation. Contemporary devices utilize predominantly centrifugal flow and, to a lesser extent, axial flow rotors that vary with respect to their intrinsic flow characteristics. Flow can be manipulated with adjustments to preload and afterload as in the native heart, and ascertainment of the predicted effects is provided by differential pressure-flow (H-Q) curves or loops. Valvular heart disease, especially aortic regurgitation, may significantly affect adequacy of mechanical support. In contrast, atrioventricular and ventriculoventricular timing is of less certain significance. Although beneficial effects of device therapy are typically seen due to enhanced distal perfusion, unloading of the left ventricle and atrium, and amelioration of secondary pulmonary hypertension, negative effects of CF-LVAD therapy on right ventricular filling and function, through right-sided loading and septal interaction, can make optimization challenging. Additionally, a lack of pulsatile energy provided by CF-LVAD therapy has physiologic consequences for end-organ function and may be responsible for a series of adverse effects. Rheological effects of intravascular pumps, especially shear stress exposure, result in platelet activation and hemolysis, which may result in both thrombotic and hemorrhagic consequences. Development of novel solutions for untoward device-circulatory interactions will facilitate hemodynamic support while mitigating adverse events. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.
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Affiliation(s)
- Andrew N Rosenbaum
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA
| | - James F Antaki
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Atta Behfar
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA.,VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - John Stulak
- Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Sudhir S Kushwaha
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA
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Ferrari G, Di Molfetta A, Zieliński K, Cusimano V, Darowski M, Kozarski M, Fresiello L. Assessment of the VAD – Native ventricle pumping system by an equivalent pump: A computational model based procedure. Biocybern Biomed Eng 2021. [DOI: 10.1016/j.bbe.2021.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Fresiello L, Gross C, Jacobs S. Exercise physiology in left ventricular assist device patients: insights from hemodynamic simulations. Ann Cardiothorac Surg 2021; 10:339-352. [PMID: 34159115 DOI: 10.21037/acs-2020-cfmcs-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Left ventricular assist devices (LVADs) assure longer survival to patients, but exercise capacity is limited compared to normal values. Overall, LVAD patients show high wedge pressure and low cardiac output during maximal exercise, a phenomenon hinting at the need for increased LVAD support. Clinical studies investigating the hemodynamic benefits of an LVAD speed increase during exercise, ended in inhomogeneous and sometimes contradictory results. The native ventricle-LVAD interaction changes between rest and exercise, and this evolution is complex, multifactorial and patient-specific. The aim of this paper is to provide a comprehensive overview on the patient-LVAD interaction during exercise and to delineate possible therapeutic strategies for the future. A computational cardiorespiratory model was used to simulate the hemodynamics of peak bicycle exercise in LVAD patients. The simulator included the main cardiovascular and respiratory impairments commonly observed in LVAD patients, so as to represent an average hemodynamic response to exercise. In addition, other exercise responses were simulated, by tuning the chronotropic, inotropic and vascular functions, and implementing aortic regurgitation and stenosis in the simulator. These profiles were tested under different LVAD speeds and LVAD pressure-flow characteristics. Simulations output showed consistency with clinical data from the literature. The simulator allowed the working condition of the assisted ventricle at exercise to be investigated, clarifying the reasons behind the high wedge pressure and poor cardiac output observed in the clinics. Patients with poorer inotropic, chronotropic and vascular functions, are likely to benefit more from an LVAD speed increase during exercise. Similarly, for these patients, a flatter LVAD pressure-flow characteristic can assure better hemodynamic support under physical exertion. Overall, the study evidenced the need for a patient-specific approach on supporting exercise hemodynamics. In this frame, a complex simulator can constitute a valuable tool to define and test personalized speed control algorithms and strategies.
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Affiliation(s)
- Libera Fresiello
- Department of Cardiovascular Sciences, Cardiac Surgery, Katholieke Universiteit Leuven, Leuven, Belgium.,Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Christoph Gross
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Steven Jacobs
- Department of Cardiovascular Sciences, Cardiac Surgery, Katholieke Universiteit Leuven, Leuven, Belgium
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9
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Moscato F, Gross C, Maw M, Schlöglhofer T, Granegger M, Zimpfer D, Schima H. The left ventricular assist device as a patient monitoring system. Ann Cardiothorac Surg 2021; 10:221-232. [PMID: 33842216 DOI: 10.21037/acs-2020-cfmcs-218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Technological progress of left ventricular assist devices (LVADs) towards rotary blood pumps and the optimization of medical management contributed to the significant improvements in patient survival as well as LVAD support duration. Even though LVAD therapy is now well-established for end-stage heart failure patients, the long-term occurrence of adverse events (AE) such as bleeding, infection or stroke, still represent a relevant burden. An early detection of AE, before onset of major symptoms, can lead to further optimization of patient treatment and thus mitigate the burden of AE. Continuous patient monitoring facilitates identification of pathophysiological states and allows anticipation of AE to improve patient management. In this paper, methods, algorithms and possibilities for continuous patient monitoring based on LVAD data are reviewed. While experience with continuous LVAD monitoring is currently limited to a few centers worldwide, the pace of developments in this field is fast and we expect these technologies to have a global impact on the well-being of LVAD patients.
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Affiliation(s)
- Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Christoph Gross
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Martin Maw
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Thomas Schlöglhofer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Marcus Granegger
- Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Daniel Zimpfer
- Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Heinrich Schima
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Division of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
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