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Gerrah R. A Universal Device to Convert a Continuous Flow Assist Device to a Pulsatile Flow Device to Simulate Normal Blood Flow and Pressure Patterns. Surg Innov 2023; 30:471-476. [PMID: 36441564 DOI: 10.1177/15533506221140534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
BACKGROUND Continuous follow assist devices (CFAD) are the most commonly used mechanical circulatory support devices. Compared to Pulsatile flow assist devices (PFAD), CFADs deliver a non-physiologic type of flow, which might contribute to complications related to lack of pulsatility in these devices. Moreover, lack of pulsatility complicates the clinical management of these patients who often present with good perfusion but with no palpable pulse and none or a negligible pulse pressure on blood pressure measurement. METHODS AND RESULTS Presented here is a concept of a universal converter device that can be added inline other CFADs to convert the flow from continuous to pulsatile, simulating a normal flow and pressure pattern. After initial implantation and stabilization with a CFAD, adding this converter might potentially provide the benefits of pulsatile physiologic flow. The device is made of 2 components connected in parallel, working in tandem in user determined cycles. The continuous flow through a specifically positioned openings create a smooth conversion to a pulsatile flow. This device can convert a continuous flow to a physiologic pulsatile flow to achieve a native-like flow pattern and potentially prevent some CFAD complications. CONCLUSION This paper presents the concept of pulsatility generation and simulation for other assist devices. Such a device can be a universal add-on or a supplemental option for CFADs.
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Affiliation(s)
- Rabin Gerrah
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, USA
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2
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Sohn SH, Kang Y, Hwang HY, Chee HK. Optimal timing of heart transplantation in patients with an implantable left ventricular assist device. KOREAN JOURNAL OF TRANSPLANTATION 2023; 37:79-84. [PMID: 37435145 PMCID: PMC10332290 DOI: 10.4285/kjt.23.0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/28/2023] [Indexed: 07/13/2023] Open
Abstract
Heart transplantation (HTPL) has been established as the gold-standard surgical treatment for end-stage heart failure. However, the use of a left ventricular assist device (LVAD) as a bridge to HTPL has been increasing due to the limited availability of HTPL donors. Currently, more than half of HTPL patients have a durable LVAD. Advances in LVAD technology have provided many benefits for patients on the waiting list for HTPL. Despite their advantages, LVADs also have limitations such as loss of pulsatility, thromboembolism, bleeding, and infection. In this narrative review, the benefits and shortcomings of LVADs as a bridge to HTPL are summarized, and the available literature evaluating the optimal timing of HTPL after LVAD implantation is reviewed. Because only a few studies have been published on this issue in the current era of third-generation LVADs, future studies are needed to draw a definite conclusion.
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Affiliation(s)
- Suk Ho Sohn
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Yoonjin Kang
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ho Young Hwang
- Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Hyun Keun Chee
- Department of Thoracic and Cardiovascular Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
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3
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Litvak M, Shamanaev A, Zalawadiya S, Matafonov A, Kobrin A, Feener EP, Wallisch M, Tucker EI, McCarty OJT, Gailani D. Titanium is a potent inducer of contact activation: implications for intravascular devices. J Thromb Haemost 2023; 21:1200-1213. [PMID: 36696212 PMCID: PMC10621279 DOI: 10.1016/j.jtha.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/07/2022] [Accepted: 12/15/2022] [Indexed: 01/09/2023]
Abstract
BACKGROUND Titanium (Ti) and its alloys are widely used in manufacturing medical devices because of their strength and resistance to corrosion. Although Ti compounds are considered compatible with blood, they appear to support plasma contact activation and may be thrombogenic. OBJECTIVES The objective of this study was to compare Ti and titanium nitride (TiN) with known activators of contact activation (kaolin and silica) in plasma-clotting assays and to assess binding and activation of factor XII, (FXII), factor XI (FXI), prekallikrein, and high-molecular-weight kininogen (HK) with Ti/TiN. METHODS Ti-based nanospheres and foils were compared with kaolin, silica, and aluminum in plasma-clotting assays. Binding and activation of FXII, prekallikrein, HK, and FXI to surfaces was assessed with western blots and chromogenic assays. RESULTS Using equivalent surface amounts, Ti and TiN were comparable with kaolin and superior to silica, for inducing coagulation and FXII autoactivation. Similar to many inducers of contact activation, Ti and TiN are negatively charged; however, their effects on FXII are not neutralized by the polycation polybrene. Antibodies to FXII, prekallikrein, or FXI or coating Ti with poly-L-arginine blocked Ti-induced coagulation. An antibody to FXII reduced FXII and PK binding to Ti, kallikrein generation, and HK cleavage. CONCLUSION Titanium compounds induce contact activation with a potency comparable with that of kaolin. Binding of FXII with Ti shares some features with FXII binding to soluble polyanions but may have unique features. Inhibitors targeting FXII or FXI may be useful in mitigating Ti-induced contact activation in patients with titanium-based implants that are exposed to blood.
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Affiliation(s)
- Maxim Litvak
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Aleksandr Shamanaev
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sandip Zalawadiya
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Anton Matafonov
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Anton Kobrin
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Edward P Feener
- KalVista Pharmaceuticals, Inc., Cambridge, Massachusetts, USA
| | - Michael Wallisch
- Aronora, Inc., Portland, Oregon, USA; Department of Biomedical Engineering, Oregon Health & Science University, Oregon, USA
| | - Erik I Tucker
- Aronora, Inc., Portland, Oregon, USA; Department of Biomedical Engineering, Oregon Health & Science University, Oregon, USA
| | - Owen J T McCarty
- Department of Biomedical Engineering, Oregon Health & Science University, Oregon, USA
| | - David Gailani
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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Li S, Jin D, Gui X, Liu G, Jiang X. Numerical analysis of different cardiac functions and support modes on blood damage potential in an axial pump. Int J Artif Organs 2023; 46:215-225. [PMID: 36941753 DOI: 10.1177/03913988231155938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
BACKGROUND Cardiac functions and support modes of left ventricular assist device (LVAD) will influence the pump inner flow field and blood damage potential. METHODS Computational fluid dynamics (CFD) method and lumped-parameter-model (LPM) were applied to investigate the impacts of cardiac functions under full (9000 rpm) and partial (8000 rpm) support modes in an axial pump. RESULTS The constitution of hemolysis index (HI) in different components of the pump was investigated. HI was found to be more sensitive to positive incidence angles (i) compared with negative incidence angles in rotors. Negative incidence angles had little impact on HI both in rotors and the outlet guide vanes. The improved cardiac function made only a minor difference in HIave (estimated average HI in one cardiac cycle) by 9.88%, as the flow rate expanded mainly to higher flow range. Switching to partial support mode, however, would induce a periodic experience of severe flow separation and recirculation at low flow range. This irregular flow field increased HIave by 47.97%, remarkably increasing the blood damage potential. CONCLUSION This study revealed the relationship between the blade incidence angle i and HI, and recommended negative-incidence-angle blade designs as it yielded lower HI. Moreover, to avoid flow range below 50% of the design point, careful evaluations should be made before switching support modes as weaning procedures in clinical applications.
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Affiliation(s)
- Shulei Li
- School of Energy and Power Engineering, Beihang University, Beijing, China
| | - Donghai Jin
- School of Energy and Power Engineering, Beihang University, Beijing, China
| | - Xingmin Gui
- School of Energy and Power Engineering, Beihang University, Beijing, China
| | - Guangmao Liu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xihang Jiang
- Beijing Power Machinery Research Institute, Beijing, China
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Correlation between aortic valve protein levels and vector flow mapping of wall shear stress and oscillatory shear index in patients supported with continuous-flow left ventricular assist devices. J Heart Lung Transplant 2023; 42:64-75. [PMID: 36400676 DOI: 10.1016/j.healun.2022.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 09/16/2022] [Accepted: 09/23/2022] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Continuous-flow left ventricular assist devices commonly lead to aortic regurgitation, which results in decreased pump efficiency and worsening heart failure. We hypothesized that non-physiological wall shear stress and oscillatory shear index alter the abundance of structural proteins in aortic valves of left ventricular assist device (LVAD) patients. METHODS Doppler images of aortic valves of patients undergoing heart transplants were obtained. Eight patients had been supported with LVADs, whereas 10 were not. Aortic valve tissue was collected and protein levels were analyzed using mass spectrometry. Echocardiographic images were analyzed and wall shear stress and oscillatory shear index were calculated. The relationship between normalized levels of individual proteins and in vivo echocardiographic measurements was evaluated. RESULTS Of the 57 proteins of interest, there was a strong negative correlation between levels of 15 proteins and the wall shear stress (R < -0.500, p ≤ 0.05), and a moderate negative correlation between 16 proteins and wall shear stress (R -0.500 to -0.300, p ≤ 0.05). Gene ontology analysis demonstrated clusters of proteins involved in cellular structure. Proteins negatively correlated with WSS included those with cytoskeletal, actin/myosin, cell-cell junction and extracellular functions. C: In aortic valve tissue, 31 proteins were identified involved in cellular structure and extracellular junctions with a negative correlation between their levels and wall shear stress. These findings suggest an association between the forces acting on the aortic valve (AV) and leaflet protein abundance, and may form a mechanical basis for the increased risk of aortic leaflet degeneration in LVAD patients.
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Fang P, Du J, Boraschi A, Bozzi S, Redaelli A, Schmid Daners M, Kurtcuoglu V, Consolo F, de Zélicourt D. Insights Into the Low Rate of In-Pump Thrombosis With the HeartMate 3: Does the Artificial Pulse Improve Washout? Front Cardiovasc Med 2022; 9:775780. [PMID: 35360020 PMCID: PMC8962620 DOI: 10.3389/fcvm.2022.775780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 02/02/2022] [Indexed: 01/14/2023] Open
Abstract
While earlier studies reported no relevant effect of the HeartMate 3 (HM3) artificial pulse (AP) on bulk pump washout, its effect on regions with prolonged residence times remains unexplored. Using numerical simulations, we compared pump washout in the HM3 with and without AP with a focus on the clearance of the last 5% of the pump volume. Results were examined in terms of flush-volume (Vf, number of times the pump was flushed with new blood) to probe the effect of the AP independent of changing flow rate. Irrespective of the flow condition, the HM3 washout scaled linearly with flush volume up to 70% washout and slowed down for the last 30%. Flush volumes needed to washout 95% of the pump were comparable with and without the AP (1.3–1.4 Vf), while 99% washout required 2.1–2.2 Vf with the AP vs. 2.5 Vf without the AP. The AP enhanced washout of the bend relief and near-wall regions. It also transiently shifted or eliminated stagnation regions and led to rapid wall shear stress fluctuations below the rotor and in the secondary flow path. Our results suggest potential benefits of the AP for clearance of fluid regions that might elicit in-pump thrombosis and provide possible mechanistic rationale behind clinical data showing very low rate of in-pump thrombosis with the HM3. Further optimization of the AP sequence is warranted to balance washout efficacy while limiting blood damage.
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Affiliation(s)
- Peng Fang
- School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen, Shenzhen, China
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Jianjun Du
- School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen, Shenzhen, China
| | - Andrea Boraschi
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Silvia Bozzi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Marianne Schmid Daners
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Filippo Consolo
- Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milano, Italy
- Università Vita Salute San Raffaele, Milano, Italy
| | - Diane de Zélicourt
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
- *Correspondence: Diane de Zélicourt
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Designing an Active Valvulated Outflow Conduit for a Continuous-Flow Left Ventricular Assist Device to Increase Pulsatility: A Simulation Study. ASAIO J 2021; 67:529-535. [PMID: 33902101 DOI: 10.1097/mat.0000000000001255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The purpose of this work was to investigate, using a lumped parameter model, the feasibility of increasing the pulsatility of a continuous-flow ventricular assist device (VAD) by implanting an active valvulated outflow cannula. A lumped parameter model was adopted for this study. VAD was modeled, starting from its pressure-flow characteristics. The valvulated outflow conduit was modeled as an active resistance described by a square function. Starting from pathologic condition, the following simulations were performed: VAD, VAD and valvulated outflow conduit in copulsation and counterpulsation with different ratios between the VAD valve opening rate and the heart rate, and asynchrony work with the heart with different VAD valve opening intervals. The copulsation 1:1 configuration and the asynchrony 0.3s-close-0.7s-open configurations permit to maximize the hemodynamic benefits provided by the presence of the active VAD outflow valvulated conduit providing an increase of arterial pulsatility from 1.86% to 14.98% without the presence of left ventricular output. The presence of the active VAD valve in the outflow conduit causes a decrement of the left ventricular unloading and of VAD flow and, that can be counteracted by increasing the VAD speed without affecting arterial pulsatility. The valvulated outflow tube provides an increase in arterial pulsatility; it can be driven in different working modality and can be potentially applicable to all types of VADs. However, the valvulated outflow conduit causes a decrement of left ventricular unloading and of the VAD flow that can be counteracted, increasing the VAD speed.
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Ivak P, Netuka I, Tucanova Z, Wohlfahrt P, Konarik M, Szarszoi O, Novakova S, Kubanek M, Lanska V, Pitha J. The Effect of Artificial Pulsatility on the Peripheral Vasculature in Patients with A Continuous-Flow Ventricular Assist Device. Can J Cardiol 2021; 37:1578-1585. [PMID: 34090978 DOI: 10.1016/j.cjca.2021.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 05/26/2021] [Accepted: 05/29/2021] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Implantation of left ventricular assist systems (LVASs) has become the standard of care for advanced heart failure (HF). The absence of pulsatility in previous devices contributes to vascular and endothelial dysfunction, related to atherosclerotic or vascular complications. We hypothesized that the artificial pulsatility provided by the HeartMate 3 (HM3) LVAS would exert a favorable effect on the vasculature. METHODS In 32 patients implanted with HM3 (5 females; mean age 55±13.6 years), the reactive hyperemia index (RHI) and peripheral augmentation index (AI), markers of endothelial function and arterial stiffness, were measured with an Endo-PAT2000 prior to and in the 3rd and 6th months after implantation. RHI and AI data from 30 HeartMate II (HM II) recipients in the 3rd and 6th months after implantation, from 15 advanced HF patients without LVASs, and from 13 healthy volunteers were also analyzed. RESULTS In HM3 recipients, the mean RHI significantly decreased at 3rd and 6th months after implantation. The RHI was substantially lower at baseline than that of healthy or HF reference group. Increasing AI values, indicating worsening arterial stiffness, were also observed. Similar trends were observed in HM II recipients between the 3rd and 6th months, but with higher absolute values of RHI and AI. CONCLUSIONS We detected impaired vascular function in HM3 patients and provided additional evidence on the negative effect of low pulsatility on vascular function after LVAS implantation. The results suggest that the artificial pulsatility of the HM3 does not avert the progression of endothelial dysfunction.
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Affiliation(s)
- Peter Ivak
- Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Department of Physiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic; Second Department of Surgery, Department of Cardiovascular Surgery, First Faculty of Medicine, Charles University, Prague, Czech Republic.
| | - Ivan Netuka
- Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Second Department of Surgery, Department of Cardiovascular Surgery, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Zuzana Tucanova
- Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Peter Wohlfahrt
- Laboratory for Atherosclerosis Research, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Miroslav Konarik
- Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; Institute of Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Ondrej Szarszoi
- Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Sarka Novakova
- Laboratory for Atherosclerosis Research, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Milos Kubanek
- Department of Cardiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Vera Lanska
- Medical Statistics Unit, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Jan Pitha
- Department of Physiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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9
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Di Molfetta A, Cusimano V, Ferrari G. Increasing the pulsatility of continuos flow VAD: comparison between a valvulated outflow cannula and speed modulation by simulation. J Artif Organs 2021; 24:146-156. [PMID: 33512579 DOI: 10.1007/s10047-020-01235-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 12/03/2020] [Indexed: 10/22/2022]
Abstract
To investigate by a lumped parameter model the feasibility of increasing the pulsatility of a continuous flow VAD, implanting an active valvulated outflow cannula and to compare the results with the haemodynamic outcome given by speed modulation methods. The concomitant presence of speed modulation and the active valvulated outflow conduit is also simulated. A lumped parameter model was adopted. VAD was modeled starting from its pressure flow characteristics with a second order polynomial equation. The valvulated outflow conduit was modeled as an active resistance described by a square function. Starting from pathological condition we simulated: VAD; VAD and valvulated outflow conduit in copulsation, counterpulsation and asynchrony work with the heart; VAD and active valvulated outflow tube and speed modulation. Copulsation 1:1 and asynchrony 0.3 s valve close-0.7 s valve open configurations maximised the haemodynamic benefits with the highest increment in pulsatility. The valvulated outflow conduit causes a decrement of the left ventricular unloading and of VAD flow that can be counteracted by increasing the VAD speed without affecting pulsatility. The concomitant use of the speed modulation and the active valvulated outflow conduit can further increase the pulsatility without altering left ventricular unloading and VAD flow. The valvulated outflow tube provide similar increase in pulsatility to speed modulation method but causes a decrement of left ventricular unloading and VAD flow that can be counteracted increasing the VAD speed or allowing a partial support. A valvulated outflow tube can be potentially applied to all continuous flow VADs.
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Affiliation(s)
- Arianna Di Molfetta
- Department of Cardiac Surgery, Policlinico Gemelli Hospital, Largo Agostino Gemelli, 8, 00100, Rome, Italy.
| | - Valerio Cusimano
- CNR-IASI BioMatLab, Italian National Research Council, Institute of Analysis, Systems and Computer Science, Biomathematics Laboratory, Rome, Italy
| | - Gianfranco Ferrari
- Institute of Biocybernetics and Biomedical Engineer, Polish Academy of Science, Warsaw, Poland
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10
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Magkoutas K, Rebholz M, Sündermann S, Alogna A, Faragli A, Falk V, Meboldt M, Schmid Daners M. Control of ventricular unloading using an electrocardiogram-synchronized pulsatile ventricular assist device under high stroke ratios. Artif Organs 2020; 44:E394-E405. [PMID: 32321193 DOI: 10.1111/aor.13711] [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] [Received: 11/19/2019] [Revised: 03/10/2020] [Accepted: 04/13/2020] [Indexed: 01/17/2023]
Abstract
Pulsatile ventricular assist devices (pVADs) yield a blood flow that imitates the pulsatile flow of the heart and, therefore, could diminish the adverse events related to the continuous flow provided by the ventricular assist devices that are commonly used. However, their intrinsic characteristics of larger size and higher weight set a burden to their implantation, that along with the frequent mechanical failures and thrombosis events, reduce the usage of pVADs in the clinical environment. In this study, we investigated the possibility to reduce the pump size by using high pump stroke ratios while maintaining the ability to control the hemodynamics of the cardiovascular system (CVS). In vitro and in vivo experiments were conducted with a custom pVAD implemented on a hybrid mock circulation system and in five sheep, respectively. The actuation of the pVAD was synchronized with the heartbeat. Variations of the pump stroke ratio, time delay between the pump stroke and the heart stroke, as well as duration of the pump systole in respect to the total cardiac cycle duration were used to evaluate the effects of various pump settings on the hemodynamics of the CVS. The results suggest that by varying the operating settings of the pVAD, a pulsatile flow that provides physiological hemodynamic parameters, as well as a control over the hemodynamic parameters, can be achieved. Additionally, by employing high pump stroke ratios, the size of the pVAD can be significantly reduced; however, at those high pump stroke ratios, the effect of the other pump parameters diminishes.
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Affiliation(s)
- Konstantinos Magkoutas
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Mathias Rebholz
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Simon Sündermann
- DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Department of Cardiovascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany
| | - Alessio Alogna
- DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Department of Internal Medicine and Cardiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Campus Virchow Klinikum, Berlin, Germany
| | - Alessandro Faragli
- DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Department of Internal Medicine and Cardiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Campus Virchow Klinikum, Berlin, Germany
| | - Volkmar Falk
- DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Department of Cardiovascular Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany.,Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Mirko Meboldt
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Marianne Schmid Daners
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
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11
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Chen Z, Jena SK, Giridharan GA, Sobieski MA, Koenig SC, Slaughter MS, Griffith BP, Wu ZJ. Shear stress and blood trauma under constant and pulse-modulated speed CF-VAD operations: CFD analysis of the HVAD. Med Biol Eng Comput 2018; 57:807-818. [PMID: 30406881 DOI: 10.1007/s11517-018-1922-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/24/2018] [Indexed: 11/30/2022]
Abstract
Modulation of pump speed has been proposed and implemented clinically to improve vascular pulsatility in continuous flow ventricular assist device patient. The flow dynamics of the HVAD with a promising asynchronous pump speed modulation and its potential risk for device-induced blood trauma was investigated numerically. The boundary conditions at the pump inlet and outlet were defined using the pressure waveforms adapted from the experimentally recorded ventricular and arterial pressure waveforms in a large animal ischemic heart failure (IHF) model supported by the HVAD operated at constant and modulated pump speeds. Shear stress fields and hemolysis indices were derived from the simulated flow fields. The overall features of the computationally generated flow waveforms at simulated constant and pulse-modulated speed operations matched with those of the experimentally recorded flow waveforms. The simulations showed that the shear stress field and hemolysis index vary throughout the cardiac cycle under the constant speed operation, and also as a function of modulation profile under modulated speed operation. The computational model did not demonstrate any differences in the time average hemolysis index between constant and modulated pump speed operations, thereby predicting pulse-modulated speed operation may help to restore vascular pulsatility without any further increased risk of blood trauma. Graphical abstract The streamline inside the HVAD pump and the wall shear stress distribution on the impeller surface at six discrete time instants over one cardiac cycle under constant speed operation (3000 rpm) (a) and under pulse-modulated speed operation (b). c Computationally predicted flow rate waveform under pulse-modulated speed operation. d Computationally predicted time-varying HI generated by the HVAD pump under the two operation modes constant speed (dash line) and pulse-modulated speed (solid line). These figures indicate that the pulse-modulated speed operation may help to restore vascular pulsatility without any further increased risk of blood trauma.
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Affiliation(s)
- Zengsheng Chen
- Artificial Organs Laboratory, Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 434A, Baltimore, MD, 21201, USA
| | - Sofen K Jena
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Guruprasad A Giridharan
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA.,Department of Bioengineering, Speed School of Engineering, University of Louisville, Louisville, KY, 40292, USA
| | - Michael A Sobieski
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Steven C Koenig
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA.,Department of Bioengineering, Speed School of Engineering, University of Louisville, Louisville, KY, 40292, USA
| | - Mark S Slaughter
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Bartley P Griffith
- Artificial Organs Laboratory, Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 434A, Baltimore, MD, 21201, USA
| | - Zhongjun J Wu
- Artificial Organs Laboratory, Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 434A, Baltimore, MD, 21201, USA. .,Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD, 20742, USA.
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Liao S, Wu EL, Neidlin M, Li Z, Simpson B, Gregory SD. The Influence of Rotary Blood Pump Speed Modulation on the Risk of Intraventricular Thrombosis. Artif Organs 2018; 42:943-953. [PMID: 30260033 DOI: 10.1111/aor.13330] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Rotary left ventricular assist devices (LVADs) are commonly operated at a constant speed, attenuating blood flow pulsatility. Speed modulation of rotary LVADs has been demonstrated to improve vascular pulsatility and pump washout. The effect of LVAD speed modulation on intraventricular flow dynamics is not well understood, which may have an influence on thromboembolic events. This study aimed to numerically evaluate intraventricular flow characteristics with a speed modulated LVAD. A severely dilated anatomical left ventricle was supported by a HeartWare HVAD in a three-dimensional multiscale computational fluid dynamics model. Three LVAD operating scenarios were evaluated: constant speed and sinusoidal co- and counter-pulsation. In all operating scenarios, the mean pump speed was set to restore the cardiac output to 5.0 L/min. Co- and counter-pulsation was speed modulated with an amplitude of 750 rpm. The risk of thrombosis was evaluated based on blood residence time, ventricular washout, kinetic energy densities, and a pulsatility index map. Blood residence time for co-pulsation was on average 1.8 and 3.7% lower than constant speed and counter-pulsation mode, respectively. After introducing fresh blood to displace preexisting blood for 10 cardiac cycles, co-pulsation had 1.5% less old blood in comparison to counter-pulsation. Apical energy densities were 84 and 27% higher for co-pulsation in comparison to counter-pulsation and constant speed mode, respectively. Co-pulsation had an increased pulsatility index around the left ventricular outflow tract and mid-ventricle. Improved flow dynamics with co-pulsation was caused by increased E-wave velocities which minimized blood stasis. In the studied scenario and from the perspective of intraventricular flow dynamics, co-pulsation of rotary LVADs could minimize the risk of intraventricular thrombosis.
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Affiliation(s)
- Sam Liao
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia.,Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Eric L Wu
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia.,School of Medicine, The University of Queensland, St. Lucia, Queensland, Australia
| | - Michael Neidlin
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Zhiyong Li
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Benjamin Simpson
- Department of Engineering, Nottingham Trent University, Clifton Lane, Nottingham, UK
| | - Shaun D Gregory
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia.,School of Medicine, The University of Queensland, St. Lucia, Queensland, Australia.,Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria, Australia
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Clinical Implications of Physiologic Flow Adjustment in Continuous-Flow Left Ventricular Assist Devices. ASAIO J 2018; 63:241-250. [PMID: 28459742 DOI: 10.1097/mat.0000000000000477] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
There is increasing evidence for successful management of end-stage heart failure with continuous-flow left ventricular assist device (CF-LVAD) technology. However, passive flow adjustment at fixed CF-LVAD speed is susceptible to flow balancing issues as well as adverse hemodynamic effects relating to the diminished arterial pulse pressure and flow. With current therapy, flow cannot be adjusted with changes in venous return, which can vary significantly with volume status. This limits the performance and safety of CF-LVAD. Active flow adjustment strategies have been proposed to improve the synchrony between the pump and the native cardiovascular system, mimicking the Frank-Starling mechanism of the heart. These flow adjustment strategies include modulation by CF-LVAD pump speed by synchrony and maintenance of constant flow or constant pressure head, or a combination of these variables. However, none of these adjustment strategies have evolved sufficiently to gain widespread attention. Herein we review the current challenges and future directions of CF-LVAD therapy and sensor technology focusing on the development of a physiologic, long-term active flow adjustment strategy for CF-LVADs.
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Rebholz M, Amacher R, Petrou A, Meboldt M, Schmid Daners M. High-frequency operation of a pulsatile VAD - a simulation study. ACTA ACUST UNITED AC 2017; 62:161-170. [PMID: 27505081 DOI: 10.1515/bmt-2016-0052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/05/2016] [Indexed: 11/15/2022]
Abstract
Ventricular assist devices (VADs) are mechanical blood pumps that are clinically used to treat severe heart failure. Pulsatile VADs (pVADs) were initially used, but are today in most cases replaced by turbodynamic VADs (tVADs). The major concern with the pVADs is their size, which prohibits full pump body implantation for a majority of patients. A reduction of the necessary stroke volume can be achieved by increasing the stroke frequency, while maintaining the same level of support capability. This reduction in stroke volume in turn offers the possibility to reduce the pump's overall dimensions. We simulated a human cardiovascular system (CVS) supported by a pVAD with three different stroke rates that were equal, two- or threefold the heart rate (HR). The pVAD was additionally synchronized to the HR for better control over the hemodynamics and the ventricular unloading. The simulation results with a HR of 90 bpm showed that a pVAD stroke volume can be reduced by 71%, while maintaining an aortic pulse pressure (PP) of 30 mm Hg, avoiding suction events, reducing the ventricular stroke work (SW) and allowing the aortic valve to open. A reduction by 67% offers the additional possibility to tune the interaction between the pVAD and the CVS. These findings allow a major reduction of the pVAD's body size, while allowing the physician to tune the pVAD according to the patient's needs.
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Affiliation(s)
- Mathias Rebholz
- pd
- z Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich
| | | | - Anastasios Petrou
- pd
- z Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich
| | - Mirko Meboldt
- pd
- z Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich
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Date K, Nishimura T, Arakawa M, Takewa Y, Kishimoto S, Umeki A, Ando M, Mizuno T, Tsukiya T, Ono M, Tatsumi E. Changing pulsatility by delaying the rotational speed phasing of a rotary left ventricular assist device. J Artif Organs 2016; 20:18-25. [DOI: 10.1007/s10047-016-0920-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 07/12/2016] [Indexed: 10/21/2022]
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16
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Design Rationale and Preclinical Evaluation of the HeartMate 3 Left Ventricular Assist System for Hemocompatibility. ASAIO J 2016; 62:375-83. [DOI: 10.1097/mat.0000000000000388] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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17
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Date K, Nishimura T, Takewa Y, Kishimoto S, Arakawa M, Umeki A, Ando M, Mizuno T, Tsukiya T, Ono M, Tatsumi E. Shifting the pulsatility by increasing the change in rotational speed for a rotary LVAD using a native heart load control system. J Artif Organs 2016; 19:315-321. [DOI: 10.1007/s10047-016-0906-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 05/08/2016] [Indexed: 10/21/2022]
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18
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Kleinheyer M, Timms DL, Greatrex NA, Masuzawa T, Frazier OH, Cohn WE. Pulsatile operation of the BiVACOR TAH - Motor design, control and hemodynamics. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:5659-62. [PMID: 25571279 DOI: 10.1109/embc.2014.6944911] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Although there is limited consensus about the strict requirement to deliver pulsatile perfusion to the human circulatory system, speed modulation of rotary blood pumps is an approach that may capture the benefits of both positive displacement and continuous flow blood pumps. In the current stage of development of the BiVACOR Total Artificial Heart emphasis is placed on providing pulsatile outflow from the pump. Multiple pulsatile speed profiles have been applied in preliminary in-vivo operation in order to assess the capability of the TAH to recreate a physiologic pulse. This paper provides an overview about recent research towards pulsatile BiVACOR operation with special emphasis on motor and control requirements and developments.
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Abstract
Continuous-flow left ventricular assist devices (LVAD) have become standard therapy option for patients with advanced heart failure. They offer several advantages over previously used pulsatile-flow LVADs, including improved durability, less surgical trauma, higher energy efficiency, and lower thrombogenicity. These benefits translate into better survival, lower frequency of adverse events, improved quality of life, and higher functional capacity of patients. However, mounting evidence shows unanticipated consequences of continuous-flow support, such as acquired aortic valve insufficiency and acquired von Willebrand syndrome. In this review article we discuss current evidence on differences between continuous and pulsatile mechanical circulatory support, with a focus on clinical implications and potential benefits of pulsatile flow.
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Affiliation(s)
- Davor Barić
- Davor Barić, Department of Cardiac Surgery and Transplantation, Dubrava University Hospital, Avenija Gojka Šuška 6, 10000 Zagreb, Croatia,
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20
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Rotary pump speed modulation for generating pulsatile flow and phasic left ventricular volume unloading in a bovine model of chronic ischemic heart failure. J Heart Lung Transplant 2015; 34:122-131. [DOI: 10.1016/j.healun.2014.09.017] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 11/22/2022] Open
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Cheng A, Williamitis CA, Slaughter MS. Comparison of continuous-flow and pulsatile-flow left ventricular assist devices: is there an advantage to pulsatility? Ann Cardiothorac Surg 2014; 3:573-81. [PMID: 25512897 DOI: 10.3978/j.issn.2225-319x.2014.08.24] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/23/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Continuous-flow left ventricular assist devices (CFVAD) are currently the most widely used type of mechanical circulatory support as bridge-to-transplant and destination therapy for end-stage congestive heart failure (HF). Compared to the first generation pulsatile-flow left ventricular assist devices (PFVADs), CFVADs have demonstrated improved reliability and durability. However, CFVADs have also been associated with certain complications thought to be linked with decreased arterial pulsatility. Previous studies comparing CFVADs and PFVADs have presented conflicting results. It is important to understand the outcome differences between CFVAD and PFVAD in order to further advance the current VAD technology. METHODS In this review, we compared the outcomes of CFVADs and PFVADs and examined the need for arterial pulsatility for the future generation of mechanical circulatory support. RESULTS CVADs offer advantages of smaller size, increased reliability and durability, and subsequent improvements in survival. However, with the increasing duration of long-term support, it appears that CFVADs may have specific complications and a lower rate of left ventricular recovery associated with diminished pulsatility, increased pressure gradients on the aortic valve and decreased compliance in smaller arterial vessels. PFVAD support or pulsatility control algorithms in CFVADs could be beneficial and potentially necessary for long term support. CONCLUSIONS Given the relative advantages and disadvantages of CFVADs and PFVADs, the ultimate solution may lie in incorporating pulsatility into current and emerging CFVADs whilst retaining their existing benefits. Future studies examining physiologic responses, end-organ function and LV remodeling at varying degrees of pulsatility and device support levels are needed.
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Affiliation(s)
- Allen Cheng
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, Kentucky 40202, USA
| | - Christine A Williamitis
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, Kentucky 40202, USA
| | - Mark S Slaughter
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, Louisville, Kentucky 40202, USA
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22
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Effect of Rotary Blood Pump Pulsatility on Potential Parameters of Blood Compatibility and Thrombosis in Inflow Cannula Tips. Int J Artif Organs 2014; 37:875-87. [DOI: 10.5301/ijao.5000361] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2014] [Indexed: 11/20/2022]
Abstract
Purpose Rotary Blood Pump (RBP) pulsatile strategies relative to the native cardiac cycle have been widely studied because of their benefits to hemodynamics. However, the effects that inducing pulses has on the blood compatibility of ventricular assist device (VAD) support have not yet been understood. Inflow cannulae have been found to be associated with thrombosis under conventional constant speed support of RBPs. To prevent further risks to blood compatibility, it is necessary to understand the relationship between cannula tip design and the induced pulsatility. The purpose of this study was to evaluate the flow field of 5 different tip geometries under RBP pulsatile support using stereo-particle image velocimetry (PIV). Methods Inflow cannulae with conventional tip geometries (blunt, blunt with 4 side ports, beveled with 3 side ports, and cage) and a custom designed crown tip were studied. All cannulae were interposed between a mixed-flow RBP and a silicone left ventricle. The contractile function and hemodynamics were reproduced in a mock circulation loop (MCL). The RBP was configured to induce synchronous and counter-synchronous pulses relative to cardiac cycles while supporting the failing ventricle. Results Between both pulsing strategies, low shear volume ([Formula: see text], potential parameter of thrombus formation) showed no significant difference. However, counter-synchronous pulsatile mode induced less increase of both high shear volume ([Formula: see text], potential parameter of platelet activation) and recirculation volume (Vz>0, potential parameter of thrombus formation). Conclusions Although the clinical relationship cannot be inferred from this measurement, when considering the inflow tips only, a necessary trade-off should be made between adverse effects on blood compatibility and benefits for hemodynamics during RBP pulsatile mode.
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Pirbodaghi T, Asgari S, Cotter C, Bourque K. Physiologic and hematologic concerns of rotary blood pumps: what needs to be improved? Heart Fail Rev 2014; 19:259-66. [PMID: 23549998 DOI: 10.1007/s10741-013-9389-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Over the past few decades, advances in ventricular assist device (VAD) technology have provided a promising therapeutic strategy to treat heart failure patients. Despite the improved performance and encouraging clinical outcomes of the new generation of VADs based on rotary blood pumps (RBPs), their physiologic and hematologic effects are controversial. Currently, clinically available RBPs run at constant speed, which results in limited control over cardiac workload and introduces blood flow with reduced pulsatility into the circulation. In this review, we first provide an update on the new challenges of mechanical circulatory support using rotary pumps including blood trauma, increased non-surgical bleeding rate, limited cardiac unloading, vascular malformations, end-organ function, and aortic valve insufficiency. Since the non-physiologic flow characteristic of these devices is one of the main subjects of scientific debate in the literature, we next emphasize the latest research regarding the development of a pulsatile RBP. Finally, we offer an outlook for future research in the field.
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Affiliation(s)
- Tohid Pirbodaghi
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland,
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24
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Pirbodaghi T, Cotter C, Bourque K. Power Consumption of Rotary Blood Pumps: Pulsatile Versus Constant-Speed Mode. Artif Organs 2014; 38:1024-8. [DOI: 10.1111/aor.12323] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Tohid Pirbodaghi
- Group for Cardiovascular Engineering, ARTORG Center for Biomedical Engineering Research; University of Bern; Bern Switzerland
- Thoratec Corporation; Burlington MA USA
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25
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Amacher R, Ochsner G, Schmid Daners M. Synchronized Pulsatile Speed Control of Turbodynamic Left Ventricular Assist Devices: Review and Prospects. Artif Organs 2014; 38:867-75. [DOI: 10.1111/aor.12253] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Raffael Amacher
- Institute for Dynamic Systems and Control; Department of Mechanical and Process Engineering; ETH Zurich; Zurich Switzerland
| | - Gregor Ochsner
- Institute for Dynamic Systems and Control; Department of Mechanical and Process Engineering; ETH Zurich; Zurich Switzerland
| | - Marianne Schmid Daners
- Institute for Dynamic Systems and Control; Department of Mechanical and Process Engineering; ETH Zurich; Zurich Switzerland
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26
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27
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Bartoli CR, Ailawadi G, Kern JA. Diagnosis, Nonsurgical Management, and Prevention of LVAD Thrombosis. J Card Surg 2013; 29:83-94. [DOI: 10.1111/jocs.12238] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Carlo R. Bartoli
- Division of Cardiovascular Surgery; University of Pennsylvania Medical Center; Philadelphia Pennsylvania
| | - Gorav Ailawadi
- Division of Thoracic and Cardiovascular Surgery; University of Virginia Health System; Charlottesville Virginia
| | - John A. Kern
- Division of Thoracic and Cardiovascular Surgery; University of Virginia Health System; Charlottesville Virginia
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28
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Jahren SE, Ochsner G, Shu F, Amacher R, Antaki JF, Vandenberghe S. Analysis of Pressure Head-Flow Loops of Pulsatile Rotodynamic Blood Pumps. Artif Organs 2013; 38:316-26. [DOI: 10.1111/aor.12139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Silje E. Jahren
- ARTORG Center for Biomedical Research; University of Bern; Bern USA
- Institute for Dynamic Systems and Control; ETH Zurich; Zurich Switzerland USA
| | - Gregor Ochsner
- Institute for Dynamic Systems and Control; ETH Zurich; Zurich Switzerland USA
| | - Fangjun Shu
- Mechanical and Aerospace Engineering Department; New Mexico State University; Las Cruces NM USA
- Department of Biomedical Engineering; Carnegie Mellon University; Pittsburgh PA USA
| | - Raffael Amacher
- Institute for Dynamic Systems and Control; ETH Zurich; Zurich Switzerland USA
| | - James F. Antaki
- Department of Biomedical Engineering; Carnegie Mellon University; Pittsburgh PA USA
| | - Stijn Vandenberghe
- ARTORG Center for Biomedical Research; University of Bern; Bern USA
- Department of Biomedical Engineering; Carnegie Mellon University; Pittsburgh PA USA
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30
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Soucy KG, Koenig SC, Giridharan GA, Sobieski MA, Slaughter MS. Defining pulsatility during continuous-flow ventricular assist device support. J Heart Lung Transplant 2013; 32:581-7. [DOI: 10.1016/j.healun.2013.02.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 01/18/2013] [Accepted: 02/26/2013] [Indexed: 10/27/2022] Open
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31
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Toptop K, Kadipasaoglu KA. Design and Numeric Evaluation of a Novel Axial-Flow Left Ventricular Assist Device. ASAIO J 2013; 59:230-9. [DOI: 10.1097/mat.0b013e31828a6bc1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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AlOmari AHH, Savkin AV, Stevens M, Mason DG, Timms DL, Salamonsen RF, Lovell NH. Developments in control systems for rotary left ventricular assist devices for heart failure patients: a review. Physiol Meas 2012; 34:R1-27. [DOI: 10.1088/0967-3334/34/1/r1] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Bartoli CR, Dowling RD. The future of adult cardiac assist devices: novel systems and mechanical circulatory support strategies. Cardiol Clin 2012; 29:559-82. [PMID: 22062206 DOI: 10.1016/j.ccl.2011.08.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The recent, widespread success of mechanical circulatory support has prompted the development of numerous implantable devices to treat advanced heart failure. It is important to raise awareness of novel device systems, the mechanisms by which they function, and implications for patient management. This article discusses devices that are being developed or are in clinical trials. Devices are categorized as standard full support, less-invasive full support, partial support: rotary pumps, partial support: counterpulsation devices, right ventricular assist device, and total artificial heart. Implantation strategy, mechanism of action, durability, efficacy, hemocompatibility, and human factors are considered. The feasibility of novel strategies for unloading the failing heart is examined.
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Affiliation(s)
- Carlo R Bartoli
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY, USA
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34
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Lim E, Alomari AHH, Savkin AV, Dokos S, Fraser JF, Timms DL, Mason DG, Lovell NH. A method for control of an implantable rotary blood pump for heart failure patients using noninvasive measurements. Artif Organs 2011; 35:E174-80. [PMID: 21843286 DOI: 10.1111/j.1525-1594.2011.01268.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We propose a deadbeat controller for the control of pulsatile pump flow (Q(p) ) in an implantable rotary blood pump (IRBP). Noninvasive measurements of pump speed and current are used as inputs to a dynamical model of Q(p) estimation, previously developed and verified in our laboratory. The controller was tested using a lumped parameter model of the cardiovascular system (CVS), in combination with the stable dynamical models of Q(p) and differential pressure (head) estimation for the IRBP. The control algorithm was tested with both constant and sinusoidal reference Q(p) as input to the CVS model. Results showed that the controller was able to track the reference input with minimal error in the presence of model uncertainty. Furthermore, Q(p) was shown to settle to the desired reference value within a finite number of sampling periods. Our results also indicated that counterpulsation yields the minimum left ventricular stroke work, left ventricular end diastolic volume, and aortic pulse pressure, without significantly affecting mean cardiac output and aortic pressure.
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Affiliation(s)
- Einly Lim
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia.
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Ando M, Nishimura T, Takewa Y, Yamazaki K, Kyo S, Ono M, Tsukiya T, Mizuno T, Taenaka Y, Tatsumi E. Electrocardiogram-Synchronized Rotational Speed Change Mode in Rotary Pumps Could Improve Pulsatility. Artif Organs 2011; 35:941-7. [DOI: 10.1111/j.1525-1594.2011.01205.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Guan Y, Karkhanis T, Wang S, Rider A, Koenig SC, Slaughter MS, El Banayosy A, Ündar A. Physiologic Benefits of Pulsatile Perfusion During Mechanical Circulatory Support for the Treatment of Acute and Chronic Heart Failure in Adults. Artif Organs 2010; 34:529-36. [DOI: 10.1111/j.1525-1594.2010.00996.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Khalil HA, Kerr DT, Schusterman MA, Cohn WE, Frazier O, Radovancevic B. Induced pulsation of a continuous-flow total artificial heart in a mock circulatory system. J Heart Lung Transplant 2010; 29:568-73. [DOI: 10.1016/j.healun.2009.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 10/28/2009] [Accepted: 12/06/2009] [Indexed: 01/27/2023] Open
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von Bayern MP, Cadeiras M, Deng MC. Destination therapy: does progress depend on left ventricular assist device development? Heart Fail Clin 2007; 3:349-67. [PMID: 17723941 DOI: 10.1016/j.hfc.2007.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The role of therapy using mechanical circulatory support devices has evolved rapidly over the last two decades. New developments in the field achieved smaller adverse events, but, currently, only minor improvements in survival were observed in published observational data. The authors discuss the development of mechanical circulatory support devices as a "destination therapy" option for patients who have end-stage heart failure and are ineligible for heart transplantation as it relates to left ventricular assist device development.
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Farrar DJ, Bourque K, Dague CP, Cotter CJ, Poirier VL. Design features, developmental status, and experimental results with the Heartmate III centrifugal left ventricular assist system with a magnetically levitated rotor. ASAIO J 2007; 53:310-5. [PMID: 17515720 DOI: 10.1097/mat.0b013e3180536694] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
A long-term left ventricular assist system for permanent use in advanced heart failure is being developed on the basis of a compact centrifugal pump with a magnetically levitated rotor and single-fault-tolerant electronics. Key features include its "bearingless" (magnetic levitation) design, textured surfaces similar to the HeartMate XVE left ventricular assist device (LVAD) to reduce anticoagulation requirements and thromboembolism, a sensorless flow estimator, and an induced pulse mode for achieving an increased level of pulsatility with continuous flow assistance. In vitro design verification testing is underway. Preclinical testing has been performed in calves demonstrating good in vivo performance at an average flow rate of 6 L/min (maximum: >11 L/min) and normal end-organ function and host response. Induced pulse mode demonstrated the ability to produce a physiological pulse pressure in vivo. Thirteen LVADs have achieved between 16 to 40 months of long-term in vitro reliability testing and will be continued until failure. Both percutaneous and fully implanted systems are in development, with a modular connection for upgrading without replacing the LVAD.
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Malchesky PS. Artificial Organs 2006: a year in review. Artif Organs 2007; 31:225-41. [PMID: 17343699 DOI: 10.1111/j.1525-1594.2007.00370.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul S Malchesky
- Artificial Organs Editorial Office, 10 West Erie Street, Painesville, OH 44077, USA.
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