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Magkoutas K, Nunes Rossato L, Heim M, Schmid Daners M. Genetic algorithm-based optimization framework for control parameters of ventricular assist devices. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2023.104788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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2
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Santos B, Cestari I. A Multi-objective Physiological Control for Continuous Flow Left Ventricular Assist Devices: Comparison of Estimator versus Sensor-based Feedback . ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-5. [PMID: 38082905 DOI: 10.1109/embc40787.2023.10340974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Left Ventricular Assist Devices have been successfully used for the treatment of Congestive Heart failure in patients who are not eligible for heart transplantation. This paper describes the implementation and comparison of the performance of a pressure sensor-based feedback controller. The strategies were tested on a mock loop of the systemic circulation. The results show that the use of pressure sensors generated a more accurate response of the controller compared to the use of estimators.Clinical Relevance- The study describes the integration of a LVAD physiological controller to a dynamic wireless monitoring system.
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Katapadi A, Umland M, Khandheria BK. Update on the Practical Role of Echocardiography in Selection, Implantation, and Management of Patients Requiring Left Ventricular Assist Device Therapy. Curr Cardiol Rep 2022; 24:1587-1597. [PMID: 35984555 DOI: 10.1007/s11886-022-01771-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/09/2022] [Indexed: 01/11/2023]
Abstract
PURPOSE OF REVIEW Echocardiography is a valuable tool for management of patients with a left ventricular assist device (LVAD). We present an updated review on the practical applications of the role of echocardiography for pre- and postoperative evaluation of patients selected. RECENT FINDINGS The LVAD is a temporary or permanent option for patients with advanced heart failure who are unresponsive to other therapy. Use of the device has its own risks, and implantation remains a complex procedure. Transthoracic and transesophageal echocardiography are useful tools for patient evaluation and monitoring both peri- and postoperatively, as we previously presented. Assessment of left and right ventricular function, complications such as thrombus formation or intracardiac shunting, and valvular disease are all important in this assessment. This also aids in predicting postoperative complications. Placement of the device is confirmed intraoperatively, and subsequent ramp studies are used to determine optimal device settings. Right ventricular (RV) failure is the most common postoperative complication and preoperative evaluation of its function is crucial. Studies suggest that tricuspid annular plane systolic excursion, RV fractional area change, and RV global longitudinal strain are strong predictors of RV failure; LV ejection fraction, size, and end-diastolic diameter are also important markers. Aortic regurgitation and mitral stenosis must always be corrected prior to LVAD placement. However, direct visualization before and after implantation, especially to rule out potential contraindications such as thrombi, cannot be overemphasized. Ramp studies remain an integral part of device optimization and may result in greater myocardial recovery than previously realized.
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Affiliation(s)
- Aashish Katapadi
- Aurora Cardiovascular and Thoracic Services, Aurora Sinai/Aurora St. Luke's Medical Centers, Advocate Aurora Health, 2801 W. Kinnickinnic River Parkway, Ste. 880, Milwaukee, WI, 53215, USA
| | - Matt Umland
- Aurora Cardiovascular and Thoracic Services, Aurora Sinai/Aurora St. Luke's Medical Centers, Advocate Aurora Health, 2801 W. Kinnickinnic River Parkway, Ste. 880, Milwaukee, WI, 53215, USA
| | - Bijoy K Khandheria
- Aurora Cardiovascular and Thoracic Services, Aurora Sinai/Aurora St. Luke's Medical Centers, Advocate Aurora Health, 2801 W. Kinnickinnic River Parkway, Ste. 880, Milwaukee, WI, 53215, USA.
- School of Medicine and Public Health, University of Wisconsin, Milwaukee, WI, 53215, USA.
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Adji A, Shehab S, Jain P, Robson D, Jansz P, Hayward CS. Arterial Compliance and Continuous-Flow Left Ventricular Assist Device Pump Function. ASAIO J 2022; 68:925-931. [PMID: 35544445 DOI: 10.1097/mat.0000000000001768] [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: 11/25/2022] Open
Abstract
Durable continuous-flow left ventricular assist devices (cfLVADs) demonstrate superior survival, cardiac functional status, and overall quality of life compared to medical therapy alone in advanced heart failure. Previous studies have not considered the impact arterial compliance may have on pump performance or developed arterial pressure. This study assessed the impact of alterations in arterial compliance, preload, and afterload on continuous-flow pump function and measured hemodynamics using an in-vitro pulsatile mock circulatory loop. Decreased arterial compliance was associated with a significant increase in arterial pressure pulsatility which was not evident in the flow pulsatility, as displayed in pump flow waveforms. There were marked changes in the pump flow waveforms due to the significant alteration in the aortoventricular gradient during diastole according to the changes in compliance. This study demonstrates that changes in systemic blood pressure, afterload, and left ventricular contractility each significantly affects the flow waveform. The association of hypertension with lower aortic compliance results in markedly decreased diastolic flow rates which may be important in contributing to a greater risk of adverse events under cfLVAD support.
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Affiliation(s)
- Audrey Adji
- From the Heart Failure and Transplant Unit, Cardiology Department, St Vincent's Hospital, Sydney, Australia
- Mechanical Circulatory Support Laboratory, Victor Chang Cardiac Research Institute, Sydney, Australia
- St Vincent's Clinical School, UNSW Medicine and Health, Sydney, Australia
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, Australia
| | - Sajad Shehab
- Mechanical Circulatory Support Laboratory, Victor Chang Cardiac Research Institute, Sydney, Australia
| | - Pankaj Jain
- From the Heart Failure and Transplant Unit, Cardiology Department, St Vincent's Hospital, Sydney, Australia
| | - Desiree Robson
- From the Heart Failure and Transplant Unit, Cardiology Department, St Vincent's Hospital, Sydney, Australia
| | - Paul Jansz
- From the Heart Failure and Transplant Unit, Cardiology Department, St Vincent's Hospital, Sydney, Australia
- Mechanical Circulatory Support Laboratory, Victor Chang Cardiac Research Institute, Sydney, Australia
- St Vincent's Clinical School, UNSW Medicine and Health, Sydney, Australia
- School of Medicine, University of Notre Dame, Sydney, Australia
| | - Christopher S Hayward
- From the Heart Failure and Transplant Unit, Cardiology Department, St Vincent's Hospital, Sydney, Australia
- Mechanical Circulatory Support Laboratory, Victor Chang Cardiac Research Institute, Sydney, Australia
- St Vincent's Clinical School, UNSW Medicine and Health, Sydney, Australia
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Maw M, Schlöglhofer T, Marko C, Aigner P, Gross C, Widhalm G, Schaefer AK, Schima M, Wittmann F, Wiedemann D, Moscato F, Kudlik D, Stadler R, Zimpfer D, Schima H. A Sensorless Modular Multiobjective Control Algorithm for Left Ventricular Assist Devices: A Clinical Pilot Study. Front Cardiovasc Med 2022; 9:888269. [PMID: 35548436 PMCID: PMC9081924 DOI: 10.3389/fcvm.2022.888269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundContemporary Left Ventricular Assist Devices (LVADs) mainly operate at a constant speed, only insufficiently adapting to changes in patient demand. Automatic physiological speed control promises tighter integration of the LVAD into patient physiology, increasing the level of support during activity and decreasing support when it is excessive.MethodsA sensorless modular control algorithm was developed for a centrifugal LVAD (HVAD, Medtronic plc, MN, USA). It consists of a heart rate-, a pulsatility-, a suction reaction—and a supervisor module. These modules were embedded into a safe testing environment and investigated in a single-center, blinded, crossover, clinical pilot trial (clinicaltrials.gov, NCT04786236). Patients completed a protocol consisting of orthostatic changes, Valsalva maneuver and submaximal bicycle ergometry in constant speed and physiological control mode in randomized sequence. Endpoints for the study were reduction of suction burden, adequate pump speed and flowrate adaptations of the control algorithm for each protocol item and no necessity for intervention via the hardware safety systems.ResultsA total of six patients (median age 53.5, 100% male) completed 13 tests in the intermediate care unit or in an outpatient setting, without necessity for intervention during control mode operation. Physiological control reduced speed and flowrate during patient rest, in sitting by a median of −75 [Interquartile Range (IQR): −137, 65] rpm and in supine position by −130 [−150, 30] rpm, thereby reducing suction burden in scenarios prone to overpumping in most tests [0 [−10, 2] Suction events/minute] in orthostatic upwards transitions and by −2 [−6, 0] Suction events/min in Valsalva maneuver. During submaximal ergometry speed was increased by 86 [31, 193] rpm compared to constant speed for a median flow increase of 0.2 [0.1, 0.8] L/min. In 3 tests speed could not be increased above constant set speed due to recurring suction and in 3 tests speed could be increased by up to 500 rpm with a pump flowrate increase of up to 0.9 L/min.ConclusionIn this pilot study, safety, short-term efficacy, and physiological responsiveness of a sensorless automated speed control system for a centrifugal LVAD was established. Long term studies are needed to show improved clinical outcomes.Clinical Trial RegistrationClinicalTrials.gov, identifier: NCT04786236.
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Affiliation(s)
- Martin Maw
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
- Ludwig-Boltzmann-Institute for Cardiovascular Research, Vienna, Austria
| | - Thomas Schlöglhofer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
- Ludwig-Boltzmann-Institute for Cardiovascular Research, Vienna, Austria
| | - Christiane Marko
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Philipp Aigner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig-Boltzmann-Institute for Cardiovascular Research, Vienna, Austria
| | - Christoph Gross
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Gregor Widhalm
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | | | - Michael Schima
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Franziska Wittmann
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Dominik Wiedemann
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Ludwig-Boltzmann-Institute for Cardiovascular Research, Vienna, Austria
| | | | | | - Daniel Zimpfer
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Heinrich Schima
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
- Ludwig-Boltzmann-Institute for Cardiovascular Research, Vienna, Austria
- *Correspondence: Heinrich Schima
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Jing T, Xin T, Wang F, Zhang Z, Zhou L. Control Strategy Design of a Microblood Pump Based on Heart-Rate Feedback. MICROMACHINES 2022; 13:mi13030358. [PMID: 35334650 PMCID: PMC8951086 DOI: 10.3390/mi13030358] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 11/16/2022]
Abstract
Based on the nonlinear relationship between heart rate and stroke volume, a flow model of left ventricular circulation was improved, and a variable-speed blood-pump control strategy based on heart-rate feedback was proposed. The control strategy was implemented on a system combining the rotary blood pump and blood circulation models of heart failure. The aortic flow of a healthy heart at different heart rates was the desired control goal. Changes in heart rate were monitored and pump speed was adjusted so that the output flow and aortic pressure of the system would match a normal heart in real time to achieve the best auxiliary state. After simulation with MATLAB, the cardiac output satisfied the ideal perfusion requirements at different heart rates, and aortic pressure demonstrated lifting and had good pulsatile performance when a variable-speed blood pump was used. The coupled model reflected the relationship between hemodynamic parameters at different heart rates with the use of the variable-speed blood pump, providing a theoretical basis for the blood-pump-assisted treatment of heart failure and the design of physiological control strategies.
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Affiliation(s)
| | | | | | | | - Ling Zhou
- Correspondence: ; Tel.: +86-138-1547-7737
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7
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Petrou A, Kanakis M, Magkoutas K, de Vries B, Meboldt M, Daners MS. Cardiac Output Estimation: Online Implementation for Left Ventricular Assist Device Support. IEEE Trans Biomed Eng 2021; 68:1990-1998. [PMID: 33338010 DOI: 10.1109/tbme.2020.3045879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We present a novel pipeline that consists of various algorithms for the estimation of the cardiac output (CO) during ventricular assist devices (VADs) support using a single pump inlet pressure (PIP) sensor as well as pump intrinsic signals. METHODS A machine learning (ML) model was constructed for the prediction of the aortic valve opening status. When a closed aortic valve is detected, the estimated CO equals the estimated pump flow. Otherwise, the estimated CO equals the sum of the estimated pump flow and the aortic valve flow, estimated via a Kalman-filter approach. Both the pathophysiological conditions and the pump speed of an in-vitro test bench were adjusted in various combinations to evaluate the performance of the pipeline, as well as the individual estimators. RESULTS The ML model yielded a Matthews correlation coefficient of 0.771, a sensitivity of 0.913 and a specificity of 0.871. An overall CO root mean square error (RMSE) of 0.69 L/min was achieved. Replacing the pump flow and aortic pressure estimators with sensors would decrease the RMSE below 0.5 L/min. CONCLUSION The performance of the proposed pipeline is considered the state of the art for VADs with an integrated PIP sensor. The effect of the individual estimators on the overall performance of the pipeline was thoroughly investigated and their limitations were identified for future research. SIGNIFICANCE The clinical application of the proposed solution could provide the clinicians with essential information about the interaction between the patient's heart and the VAD to further improve the VAD therapy.
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Emmanuel S, Jansz P, Hayward C. How well do we understand pulsatility in the context of modern ventricular assist devices? Int J Artif Organs 2021; 44:923-929. [PMID: 33960234 DOI: 10.1177/03913988211012707] [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: 11/15/2022]
Abstract
BACKGROUND Modern ventricular assist devices (VADs) use a continuous flow design. It has been suggested that a lack of pulsatility contributes to a range of adverse outcomes including pump thrombus, gastrointestinal bleeding and stroke. To better assess the role of pulsatility in these adverse events, we first require a clear definition of 'pulsatility' in the setting of a severely impaired ventricle and a modern continuous flow VAD. METHODS A literature review was conducted to elucidate the understanding of pulsatility in modern VAD literature. Search engines used included PUBMED, EMBASE and the Cochrane library. Articles were appraised on three aspects: Whether they mentioned pulsatility; whether they mentioned which pulsatility measure was used and finally which methodology was used to obtain the value. RESULTS Of 354 articles reviewed, only 13 met our broad inclusion criteria. Of these articles, the most cited measure was pulsatility index (PI) - used by 11 of the publications. The methodology used to obtain the value was not uniform and five articles did not clearly state it. Other measures included pulse pressure and surplus haemodynamic energy. The majority of articles did not directly discuss pulsatility in the setting of patient-pump interaction. CONCLUSION Most publications did not provide a definition for pulsatility. In those that did, the most common measure was PI. Measuring PI was not standardised. Few papers addressed the impact of intrinsic ventricular function and arterial compliance on pulsatility. We suggest that future publications adopt a uniform definition which encompasses both patient and pump characteristics.
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Affiliation(s)
- Sam Emmanuel
- St Vincent's Hospital (Sydney), Darlinghurst, NSW, Australia.,School of Medicine, University of New South Wales, Sydney, Australia.,School of Medicine, University of Notre Dame, Sydney, Australia.,Victor Chang Cardiac Research Institute, Sydney, Australia
| | - Paul Jansz
- St Vincent's Hospital (Sydney), Darlinghurst, NSW, Australia.,School of Medicine, University of New South Wales, Sydney, Australia.,School of Medicine, University of Notre Dame, Sydney, Australia.,Victor Chang Cardiac Research Institute, Sydney, Australia
| | - Christopher Hayward
- St Vincent's Hospital (Sydney), Darlinghurst, NSW, Australia.,School of Medicine, University of New South Wales, Sydney, Australia.,Victor Chang Cardiac Research Institute, Sydney, Australia
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9
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Stephens AF, Gregory SD, Burrell AJC, Marasco S, Stub D, Salamonsen RF. Physiological principles of Starling-like control of rotary ventricular assist devices. Expert Rev Med Devices 2020; 17:1169-1182. [PMID: 33094673 DOI: 10.1080/17434440.2020.1841631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Introduction: This review explores the Starling-like physiological control method (SLC) for rotary ventricular assist devices (VADs) for severe heart failure. The SLC, based on mathematical models of the circulation, has two functions modeling each ventricle. The first function controls the output of the VAD to the arterial pool according to Starling's law, while the second function accounts for how the blood returns to the heart from the veins. The article aims to expose clinicians to SLC in an accessible and clinically relevant discussion. Areas Covered: The article explores the physiology underlying the controller, its development and how that physiology can be adapted to SLC. Examples of controller performance are demonstrated and discussed using a benchtop model of the cardiovascular system. A discussion of the limitations and criticisms of SLC is presented, followed by a future outlook on the clinical adoption of SLC. Expert Opinion: Due to its simplicity and emulation of the natural cardiac autoregulation, SLC is the superior physiological control method for rotary VADs. However, current technical and regulatory challenges prevent the clinical translation of SLC of VADs. Further technical and regulatory development will enable the clinical translation of SLCs of VADs in the coming years.
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Affiliation(s)
- Andrew F Stephens
- Department of Mechanical and Aerospace Engineering, Monash University , Melbourne, Australia.,Cardiorespiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute , Melbourne, Australia
| | - Shaun D Gregory
- Department of Mechanical and Aerospace Engineering, Monash University , Melbourne, Australia.,Cardiorespiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute , Melbourne, Australia
| | | | - Silvana Marasco
- Department of Cardiothoracic Surgery, Alfred Hospital , Melbourne, Australia
| | - Dion Stub
- Cardiorespiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute , Melbourne, Australia.,Department of Cardiology, Alfred Hospital , Melbourne, Australia.,Department of Epidemiology and Preventive Medicine, Monash University , Melbourne, Australia
| | - Robert F Salamonsen
- Intensive Care Unit, Alfred Hospital , Melbourne, Australia.,Department of Epidemiology and Preventive Medicine, Monash University , Melbourne, Australia
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Dual SA, Llerena Zambrano B, Sündermann S, Cesarovic N, Kron M, Magkoutas K, Hengsteler J, Falk V, Starck C, Meboldt M, Vörös J, Schmid Daners M. Continuous Heart Volume Monitoring by Fully Implantable Soft Strain Sensor. Adv Healthc Mater 2020; 9:e2000855. [PMID: 32893478 DOI: 10.1002/adhm.202000855] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/12/2020] [Indexed: 12/11/2022]
Abstract
Cardiothoracic open-heart surgery has revolutionized the treatment of cardiovascular disease, the leading cause of death worldwide. After the surgery, hemodynamic and volume management can be complicated, for example in case of vasoplegia after endocarditis. Timely treatment is crucial for outcomes. Currently, treatment decisions are made based on heart volume, which needs to be measured manually by the clinician each time using ultrasound. Alternatively, implantable sensors offer a real-time window into the dynamic function of our body. Here it is shown that a soft flexible sensor, made with biocompatible materials, implanted on the surface of the heart, can provide continuous information of the heart volume after surgery. The sensor works robustly for a period of two days on a tensile machine. The accuracy of measuring heart volume is improved compared to the clinical gold standard in vivo, with an error of 7.1 mL for the strain sensor versus impedance and 14.0 mL versus ultrasound. Implanting such a sensor would provide essential, continuous information on heart volume in the critical time following the surgery, allowing early identification of complications, facilitating treatment, and hence potentially improving patient outcome.
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Affiliation(s)
- Seraina A. Dual
- Product Development Group Zurich ETH Zurich Tannenstrasse 3 Zurich 8092 Switzerland
- Cardiothoracic Surgery Stanford University Stanford CA 94305‐5101 USA
| | - Byron Llerena Zambrano
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
| | - Simon Sündermann
- DZHK (German Center for Cardiovascular Research) Partner Site Berlin 10785 Berlin Germany
- Department of Cardiovascular Surgery Charité—Universitätsmedizin Berlin Charitéplatz 1 10117 Berlin Germany
- Department of Cardiothoracic and Vascular Surgery German Heart Center Berlin Augustenburger Pl. 1 13353 Berlin Germany
| | - Nikola Cesarovic
- Department of Cardiothoracic and Vascular Surgery German Heart Center Berlin Augustenburger Pl. 1 13353 Berlin Germany
- Department of Health Sciences and Technology Tannenstrasse 3 Zürich 8092 Switzerland
- Division for Surgical Research University Hospital Zurich and University of Zurich Rämistrasse 100 Zürich 8091 Switzerland
| | - Mareike Kron
- Division for Surgical Research University Hospital Zurich and University of Zurich Rämistrasse 100 Zürich 8091 Switzerland
| | | | - Julian Hengsteler
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
| | - Volkmar Falk
- DZHK (German Center for Cardiovascular Research) Partner Site Berlin 10785 Berlin Germany
- Department of Cardiovascular Surgery Charité—Universitätsmedizin Berlin Charitéplatz 1 10117 Berlin Germany
- Department of Cardiothoracic and Vascular Surgery German Heart Center Berlin Augustenburger Pl. 1 13353 Berlin Germany
- Department of Health Sciences and Technology Tannenstrasse 3 Zürich 8092 Switzerland
| | - Christoph Starck
- DZHK (German Center for Cardiovascular Research) Partner Site Berlin 10785 Berlin Germany
| | - Mirko Meboldt
- Product Development Group Zurich ETH Zurich Tannenstrasse 3 Zurich 8092 Switzerland
| | - János Vörös
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
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11
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Koh V, Pauls J, Wu E, Stevens M, Ho Y, Lovell N, Lim E. A centralized multi-objective model predictive control for a biventricular assist device: An in vitro evaluation. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.101914] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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A Novel Control Method for Rotary Blood Pumps as Left Ventricular Assist Device Utilizing Aortic Valve State Detection. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1732160. [PMID: 31886175 PMCID: PMC6927030 DOI: 10.1155/2019/1732160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/29/2019] [Accepted: 08/08/2019] [Indexed: 12/28/2022]
Abstract
A novel control method for rotary blood pumps is proposed relying on two different objectives: regulation of pump flow in accordance with desired value and the maintenance of partial support with an open aortic valve by the variation of pump speed. The estimation of pump flow and detection of aortic valve state was performed with mathematical models describing the first- and second generation of Sputnik rotary blood pumps. The control method was validated using a cardiovascular system model. The state of the aortic valve was detected with a mean accuracy of 91% for Sputnik 1 and 96.2% for Sputnik 2 when contractility, heart rate, and systemic vascular resistance was changed. In silico results for both pumps showed that the proposed control method can achieve the desired pump flow level and maintain the open state of the aortic valve by periodically switching between two objectives under contractility, heart rate, and systemic vascular resistance changes. The proposed method showed its potential for safe operation without adverse events and for the improvement of chances for myocardial recovery.
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13
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Patel S, Rizvi SSA, Choi JH, Horan DP, Weber MP, Maynes EJ, Luc JGY, Aburjania N, Entwistle JW, Morris RJ, Massey HT, Tchantchaleishvili V. Management and outcomes of left ventricular assist device-associated endocarditis: a systematic review. Ann Cardiothorac Surg 2019; 8:600-609. [PMID: 31832350 DOI: 10.21037/acs.2019.04.04] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Left ventricular assist device (LVAD)-associated endocarditis remains poorly studied, especially in newer continuous-flow LVADs (CF-LVADs). The aim of this review was to assess outcomes of patients with LVAD-associated endocarditis, as stratified by CF-LVAD and pulsatile LVAD (P-LVAD) use as well as by different interventions and pathogen types. Methods An electronic search was performed to identify studies in the English literature on LVAD-associated endocarditis. Results Overall, 16 articles with 26 patients were included; seven had CF-LVADs and 19 had P-LVADs; time to development of endocarditis was 91 days (152 vs. 65 days, respectively, P=0.05). Eleven of 25 patients were treated with antibiotics only. Remaining 14 patients received antibiotics, however, they also underwent additional surgical intervention. One patient was treated with embolization alone for mycotic aneurysm and was therefore excluded. At a median follow-up time of 344 days post implant, there was no difference in overall mortality between CF-LVAD and P-LVAD-associated endocarditis patients (57.9% vs. 42.9%, P=0.81). Patients who underwent additional surgical intervention had higher overall survival compared to those treated with antibiotics alone (71.4% vs. 27.3%, P=0.07); with no difference in outcomes amongst those who underwent surgical device exchange as compared to heart transplantation (80.0% vs. 66.7%; P=0.23). Conclusions Compared to patients with P-LVADs, CF-LVAD patients appeared to be resistant to early development of LVAD-associated endocarditis. There was a trend towards high survival observed amongst patients who underwent additional surgical intervention as compared to those treated with antibiotics alone, with no difference amongst surgical device exchange as compared to heart transplantation. Advantages of additional surgical intervention vs. medical therapy alone deserves further exploration to determine its applicability in CF-LVADs.
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Affiliation(s)
- Sinal Patel
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Syed Saif Abbas Rizvi
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jae Hwan Choi
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Dylan P Horan
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Matthew P Weber
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Elizabeth J Maynes
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jessica G Y Luc
- Division of Cardiovascular Surgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nana Aburjania
- Division of Infectious Diseases, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - John W Entwistle
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Rohinton J Morris
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Howard T Massey
- Division of Cardiac Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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14
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WU XIAO, ZHANG XIWEN, HAO PENGFEI, HE FENG. COMPARISON OF THREE CONTROL STRATEGIES FOR AXIAL BLOOD PUMP. J MECH MED BIOL 2019. [DOI: 10.1142/s0219519419500581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Facing the gradually increased prevalence of heart failure (HF) and the shortage of donated hearts, the blood pump is widely used to prolong the life of end-stage HF patients: however, the pump generates continuous flow under constant rotational speed, declining the arterial pulsatility and causing related complications. Previous studies show that synchronous copulsation might be the best control strategy for restoring pulsatility, but synchronous strategies are needed to monitor the phase of the heartbeat, which will make the controller complex and impair its robustness. Here, we compare constant speed, synchronous copulsation in a model of a cardiovascular system with a blood pump, which shows that copulsation offers more arterial pulsatility, less pump power-consumption, and thus better battery endurance, and constant speed offers a greater ventricular unloading effect. Meanwhile, we design a strategy based on transforming left ventricular pressure, which is easier to implement and has similar effect to synchronous copulsation.
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Affiliation(s)
- XIAO WU
- School of Aerospace Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - XIWEN ZHANG
- School of Aerospace Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - PENGFEI HAO
- School of Aerospace Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - FENG HE
- School of Aerospace Engineering, Tsinghua University, Beijing 100084, P. R. China
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Malchesky PS. Vakhtang Tchantchaleishvili, MD to Serve as a Co‐Editor of Adult Circulatory Support for
Artificial Organs. Artif Organs 2019; 43:937-938. [DOI: 10.1111/aor.13554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Preload Sensitivity with TORVAD Counterpulse Support Prevents Suction and Overpumping. Cardiovasc Eng Technol 2019; 10:520-530. [PMID: 31187397 PMCID: PMC6717040 DOI: 10.1007/s13239-019-00419-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 05/29/2019] [Indexed: 01/14/2023]
Abstract
PURPOSE This study compares preload sensitivity of continuous flow (CF) VAD support to counterpulsation using the Windmill toroidal VAD (TORVAD). The TORVAD is a two-piston rotary pump that ejects 30 mL in early diastole, which increases cardiac output while preserving aortic valve flow. METHODS Preload sensitivity was compared for CF vs. TORVAD counterpulse support using two lumped parameter models of the cardiovascular system: (1) an open-loop model of the systemic circulation was used to obtain ventricular function curves by isolating the systemic circulation and prescribing preload and afterload boundary conditions, and (2) a closed-loop model was used to test the physiological response to changes in pulmonary vascular resistance, systemic vascular resistance, heart rate, inotropic state, and blood volume. In the open-loop model, ventricular function curves (cardiac output vs left ventricular preload) are used to assess preload sensitivity. In the closed-loop model, left ventricular end systolic volume is used to assess the risk of left ventricular suction. RESULTS At low preloads of 5 mmHg, CF support overpumps the circulation compared to TORVAD counterpulse support (cardiac output of 3.3 L/min for the healthy heart, 4.7 with CF support, and 3.5 with TORVAD counterpulse support) and has much less sensitivity than counterpulse support (0.342 L/min/mmHg for the healthy heart, 0.092 with CF support, and 0.306 with TORVAD counterpulse support). In the closed-loop model, when PVR is increased beyond 0.035 mmHg s/mL, CF support overpumps the circulation and causes ventricular suction events, but TORVAD counterpulse support maintains sufficient ventricular volume and does not cause suction. CONCLUSIONS Counterpulse support with the TORVAD preserves aortic valve flow and provides physiological sensitivity across all preload conditions. This should prevent overpumping and minimize the risk of suction.
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Stephens A, Gregory S, Tansley G, Busch A, Salamonsen R. In vitro evaluation of an adaptive Starling-like controller for dual rotary ventricular assist devices. Artif Organs 2019; 43:E294-E307. [PMID: 31188476 DOI: 10.1111/aor.13510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/19/2019] [Accepted: 05/31/2019] [Indexed: 01/02/2023]
Abstract
Rotary ventricular assist devices (VADs) operated clinically under constant speed control (CSC) cannot respond adequately to changes in patient cardiac demand, resulting in sub-optimal VAD flow regulation. Starling-like control (SLC) of VADs mimics the healthy ventricular flow regulation and automatically adjusts VAD speed to meet varying patient cardiac demand. The use of a fixed control line (CL - the relationship between ventricular preload and VAD flow) limits the flow regulating capability of the controller, especially in the case of exercise. Adaptive SLC (ASLC) overcomes this limitation by allowing the controller to adapt the CL to meet a diverse range of circulatory conditions. This study evaluated ASLC, SLC and CSC in a biventricular supported mock circulation loop under the simulated conditions of exercise, sleep, fluid loading and systemic hypertension. Each controller was evaluated on its ability to remain within predefined limits of VAD flow, preload, and afterload. The ASLC produced superior cardiac output (CO) during exercise (10.1 L/min) compared to SLC (7.3 L/min) and CSC (6.3 L/min). The ASLC produced favourable haemodynamics during sleep, fluid loading and systemic hypertension and could remain within a predefined haemodynamic range in three out of four simulations, suggesting improved haemodynamic performance over SLC and CSC.
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Affiliation(s)
- Andrew Stephens
- Department of Mechanical and Aerospace Engineering, Monash University, Victoria, Australia.,Cardiorespiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute, Victoria, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Queensland, Australia.,School of Engineering and Built Environment, Griffith Sciences, Griffith University, Queensland, Australia
| | - Shaun Gregory
- Department of Mechanical and Aerospace Engineering, Monash University, Victoria, Australia.,Cardiorespiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute, Victoria, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Queensland, Australia.,School of Engineering and Built Environment, Griffith Sciences, Griffith University, Queensland, Australia
| | - Geoff Tansley
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Queensland, Australia.,School of Engineering and Built Environment, Griffith Sciences, Griffith University, Queensland, Australia
| | - Andrew Busch
- School of Engineering and Built Environment, Griffith Sciences, Griffith University, Queensland, Australia
| | - Robert Salamonsen
- Department of Epidemiology and Preventive Medicine, Monash University, Victoria, Australia
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Dual SA, Pergantis P, Schoenrath F, Keznickl-Pulst J, Falk V, Meboldt M, Daners MS. Acute changes in preload and the QRS amplitude in advanced heart failure patients. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab23e8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Luc JG, Tchantchaleishvili V, Phan K, Dunlay SM, Maltais S, Stulak JM. Medical Therapy As Compared To Surgical Device Exchange for Left Ventricular Assist Device Thrombosis: A Systematic Review and Meta-Analysis. ASAIO J 2019; 65:307-317. [DOI: 10.1097/mat.0000000000000833] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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A centralized multi-objective model predictive control for a biventricular assist device: An in silico evaluation. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2018.10.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Viscosity Prediction in a Physiologically Controlled Ventricular Assist Device. IEEE Trans Biomed Eng 2018; 65:2355-2364. [DOI: 10.1109/tbme.2018.2797424] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Petrou A, Kuster D, Lee J, Meboldt M, Schmid Daners M. Comparison of Flow Estimators for Rotary Blood Pumps: An In Vitro and In Vivo Study. Ann Biomed Eng 2018; 46:2123-2134. [PMID: 30054851 DOI: 10.1007/s10439-018-2106-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/20/2018] [Indexed: 10/28/2022]
Abstract
Various approaches for estimating the flow rate of a rotary blood pump have been proposed for monitoring and control purposes. They have been evaluated under different test conditions and, therefore, a direct comparison among them is difficult. Furthermore, a limited performance has been reported for the areas where the pump flow and motor current present a non-monotonic relationship. In this regard, we selected most approaches that have been presented in literature and added a modified one, resulting in four estimators, which are either non-invasive or invasive, i.e., inlet and outlet pump pressure sensors are used. Data from in vitro and in vivo studies with the Deltastream pump DP2 were used to compare the estimators under the same test conditions. These data included both constant and varying pre- and afterload, contractility, viscosity, as well as pump speed settings. Bland-Altman plots were used to evaluate the performance of the estimators. The mean error of the overall estimated flow in vitro ranged from 0.002 to 0.38 L/min and the limits of agreement (LoA) between ± 2 L/min. During negative flows the mean error decreased by about 25% when the pump inlet pressure was added as an input. In vivo, the mean errors increased, while the LoA remained in the same range. An estimator based on pump pressure difference improves the reliability in areas where flow and current relationship is not monotonic. A trade-off between estimation accuracy and number of sensors was identified. The estimation objective and the potential errors should be considered when selecting an estimation approach and designing the pump systems.
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Affiliation(s)
- Anastasios Petrou
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092, Zurich, Switzerland
| | - Daniel Kuster
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092, Zurich, Switzerland
| | - Jongseok Lee
- German Aerospace Center (DLR), Institute of Robotics and Mechatronics, 82234, Wessling, Germany
| | - Mirko Meboldt
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092, Zurich, Switzerland
| | - Marianne Schmid Daners
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092, Zurich, Switzerland.
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A Versatile Hybrid Mock Circulation for Hydraulic Investigations of Active and Passive Cardiovascular Implants. ASAIO J 2018; 65:495-502. [PMID: 30045051 PMCID: PMC6615934 DOI: 10.1097/mat.0000000000000851] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Supplemental Digital Content is available in the text. During the development process of active or passive cardiovascular implants, such as ventricular assist devices or vascular grafts, extensive in-vitro testing is required. The aim of the study was to develop a versatile hybrid mock circulation (HMC) which can support the development of such implants that have a complex interaction with the circulation. The HMC operates based on the hardware-in-the-loop concept with a hydraulic interface of four pressure-controlled reservoirs allowing the interaction of the implant with a numerical model of the cardiovascular system. Three different conditions were investigated to highlight the versatility and the efficacy of the HMC during the development of such implants: 1) biventricular assist device (BiVAD) support with progressive aortic valve insufficiency, 2) total artificial heart (TAH) support with increasing pulmonary vascular resistance, and 3) flow distribution in a total cavopulmonary connection (TCPC) in a Fontan circulation during exercise. Realistic pathophysiologic waveforms were generated with the HMC and all hemodynamic conditions were simulated just by adapting the software. The results of the experiments indicated the potential of physiologic control during BiVAD or TAH support to prevent suction or congestion events, which may occur during constant-speed operation. The TCPC geometry influenced the flow distribution between the right and the left pulmonary artery, which was 10% higher in the latter and led to higher pressures. Together with rapid prototyping methods, the HMC may enhance the design of implants to achieve better hemodynamics. Validation of the models with clinical recordings is suggested for increasing the reliability of the HMC.
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Applications of Implantable Hemodynamic Monitoring in the Setting of Durable Mechanical Circulatory Support. ASAIO J 2018; 64:283-285. [PMID: 29620610 DOI: 10.1097/mat.0000000000000777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Pagani FD. Early postoperative hemodynamic monitoring in patients with a left ventricular assist device: More than just numbers. J Thorac Cardiovasc Surg 2018; 155:1058. [PMID: 29305031 DOI: 10.1016/j.jtcvs.2017.10.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 10/26/2017] [Indexed: 10/18/2022]
Affiliation(s)
- Francis D Pagani
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, Mich.
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Petrou A, Lee J, Dual S, Ochsner G, Meboldt M, Schmid Daners M. Standardized Comparison of Selected Physiological Controllers for Rotary Blood Pumps: In Vitro Study. Artif Organs 2017; 42:E29-E42. [DOI: 10.1111/aor.12999] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/19/2017] [Accepted: 06/29/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Anastasios Petrou
- Department of Mechanical and Process Engineering, Product Development Group Zurich; ETH Zurich; Zurich, Switzerland
| | - Jongseok Lee
- Department of Mechanical and Process Engineering, Product Development Group Zurich; ETH Zurich; Zurich, Switzerland
| | - Seraina Dual
- Department of Mechanical and Process Engineering, Product Development Group Zurich; ETH Zurich; Zurich, Switzerland
| | - Gregor Ochsner
- Department of Mechanical and Process Engineering, Product Development Group Zurich; ETH Zurich; Zurich, Switzerland
| | - Mirko Meboldt
- Department of Mechanical and Process Engineering, Product Development Group Zurich; ETH Zurich; Zurich, Switzerland
| | - Marianne Schmid Daners
- Department of Mechanical and Process Engineering, Product Development Group Zurich; ETH Zurich; Zurich, Switzerland
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Left Ventricular Assist Devices: Challenges Toward Sustaining Long-Term Patient Care. Ann Biomed Eng 2017; 45:1836-1851. [DOI: 10.1007/s10439-017-1858-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/22/2017] [Indexed: 11/25/2022]
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Tchantchaleishvili V, Phillips SJ. Update in Artificial Heart Technology: Are We There Yet? Artif Organs 2017; 40:1099-1100. [PMID: 27911029 DOI: 10.1111/aor.12877] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 11/29/2022]
Affiliation(s)
| | - Steven J Phillips
- U.S. Department of Health and Human Services, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
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