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Gerhard EF, Wang L, Singh R, Schueler S, Genovese LD, Woods A, Tang D, Smith NR, Psotka MA, Tovey S, Desai SS, Jakovljevic DG, MacGowan GA, Shah P. LVAD decommissioning for myocardial recovery: Long-term ventricular remodeling and adverse events. J Heart Lung Transplant 2021; 40:1560-1570. [PMID: 34479776 PMCID: PMC8627486 DOI: 10.1016/j.healun.2021.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/27/2021] [Accepted: 08/03/2021] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Left ventricular assist devices (LVADs) mechanically unload the heart and coupled with neurohormonal therapy can promote reverse cardiac remodeling and myocardial recovery. Minimally invasive LVAD decommissioning with the device left in place has been reported to be safe over short-term follow-up. Whether device retention reduces long-term safety, or sustainability of recovery is unknown. METHODS This is a dual-center retrospective analysis of patients who had achieved responder status (left ventricular ejection fraction, LVEF ≥40% and left ventricular internal diastolic diameter, LVIDd ≤6.0 cm) and underwent elective LVAD decommissioning for myocardial recovery from May 2010 to January 2020. All patients had outflow graft closure and driveline resection with the LVAD left in place. Emergent LVAD decommissioning for an infection or device thrombosis was excluded. Patients were followed with serial echocardiography for up to 3-years. The primary clinical outcome was survival free of heart failure hospitalization, LVAD reimplantation, or transplant. RESULTS During the study period 515 patients received an LVAD and 29 (5.6%) achieved myocardial recovery, 12 patients underwent total device explantation or urgent device decommissioning, 17 patients underwent elective LVAD decommissioning, and were included in the analysis. Median age of patients at LVAD implantation was 42 years (interquartile range, IQR: 25-54 years), all had a nonischemic cardiomyopathy, and 5 (29%) were female. At LVAD implantation, median LVEF was 10% (IQR: 5%-15%), and LVIDd 6.6 cm (IQR: 5.8-7.1 cm). There were 11 hydrodynamically levitated centrifugal-flow (65%), and 6 axial-flow LVADs (35%). The median duration of LVAD support before decommissioning was 28.7 months (range 13.5-36.2 months). As compared to the turndown study parameters, 1-month post-decommissioning, median LVEF decreased from 55% to 48% (p = 0.03), and LVIDd increased from 4.8 cm to 5.2 cm (p = 0.10). There was gradual remodeling until 6 months, after which there was no statistical difference on follow-up through 3-years (LVEF 42%, LVIDd 5.6 cm). Recurrent infections affected 41% of patients leading to 3 deaths and 1 complete device explant. Recurrent HF occurred in 1 patient who required a transplant. Probability of survival free of HF, LVAD, or transplant was 94% at 1-year, and 78% at 3-years. CONCLUSIONS LVAD decommissioning for myocardial recovery was associated with excellent long-term survival free from recurrent heart failure and preservation of ventricular size and function up to 3-years. Reducing the risk of recurrent infections, remains an important therapeutic goal for this management strategy.
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Affiliation(s)
- Eleanor F Gerhard
- Heart Failure, Mechanical Circulatory Support and Transplantation, Inova Heart and Vascular Institute, Falls Church, Virginia; George Washington University School of Medicine, Washington DC, Washington DC
| | - Lu Wang
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ramesh Singh
- Cardiac Surgery, Inova Heart and Vascular Institute, Falls Church, Virginia
| | - Stephan Schueler
- Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne, United Kingdom
| | - Leonard D Genovese
- Heart Failure, Mechanical Circulatory Support and Transplantation, Inova Heart and Vascular Institute, Falls Church, Virginia
| | - Andrew Woods
- Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne, United Kingdom
| | - Daniel Tang
- Cardiac Surgery, Inova Heart and Vascular Institute, Falls Church, Virginia
| | | | - Mitchell A Psotka
- Heart Failure, Mechanical Circulatory Support and Transplantation, Inova Heart and Vascular Institute, Falls Church, Virginia
| | - Sian Tovey
- Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne, United Kingdom
| | - Shashank S Desai
- Heart Failure, Mechanical Circulatory Support and Transplantation, Inova Heart and Vascular Institute, Falls Church, Virginia
| | | | - Guy A MacGowan
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Palak Shah
- Heart Failure, Mechanical Circulatory Support and Transplantation, Inova Heart and Vascular Institute, Falls Church, Virginia.
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Ortiz S, Vu V, Montes R, May-Newman K. Left Ventricular Flow Dynamics with the HeartMate3 Left Ventricular Assist Device: Effect of Inflow Cannula Position and Speed Modulation. ASAIO J 2021; 67:1301-1311. [PMID: 34261878 DOI: 10.1097/mat.0000000000001523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Improper left ventricular assist device (LVAD) inflow cannula (IC) positioning creates areas of stasis and low pulsatility that predispose thromboembolism, but may be mitigated with LVAD speed modulation. A mock loop study was performed to assess the sensitivity of left ventricle (LV) flow architecture to IC position and speed modulation during HeartMate3 support. System pressure, flow, and the time-resolved velocity field were measured within a transparent silicone LV for three IC angles and three IC insertion depths at matched levels of cardiac function and LVAD speed. Inflow cannula angulation towards the septum increased the resistance to LVAD flow as well as increasing the size and energy of the counter-clockwise (CCW) vortex. Apical velocity was reduced compared to IC angulation towards the mitral valve, but regional pulsatility was maintained across all angles and LVAD speeds. Increased IC protrusion decreased LVAD flow resistance, increasing velocity within the IC but reducing flow and pulsatility in the adjacent apical region. Increasing LVAD flow resistance improves aortic valve opening and strengthens the CCW vortex which directs inflow towards the septum, producing higher blood residence time and shear activation potential. Despite this impact on flow architecture, pulsatility reduction with increased LVAD speed was minimal with the HeartMate3 speed modulation feature.
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Affiliation(s)
- Sean Ortiz
- From the Bioengineering Program, Department of Mechanical Engineering, San Diego State University, San Diego, California
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Ghodrati M, Schlöglhofer T, Maurer A, Khienwad T, Zimpfer D, Beitzke D, Zonta F, Moscato F, Schima H, Aigner P. Effects of the atrium on intraventricular flow patterns during mechanical circulatory support. Int J Artif Organs 2021; 45:421-430. [PMID: 34715752 PMCID: PMC8922056 DOI: 10.1177/03913988211056018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Simulations of the ventricular flow patterns during left ventricular assist device (LVAD) support are mainly performed with idealized cylindrical inflow, neglecting the influence of the atrial vortex. In this study, the influence of the left atrium (LA) on the intra-ventricular flow was investigated via Computational Fluid Dynamics (CFD) simulations. Ventricular flow was simulated by a combined Eulerian (carrier flow)/Lagrangian (particles) approach taking into account either the LA or a cylindrical inflow section to mimic a fully support condition. The flow deviation at the mitral valve, the blood low-velocity volume as well as the residence time and shear stress history of the particles were calculated. Inclusion of the LA deflects the flow at the mitral valve by 25°, resulting in an asymmetric flow jet entering the left ventricle. This reduced the ventricular low-velocity volume by 40% (from 6.4 to 3.9 cm3), increased (40%) the shear stress experienced by particles and correspondingly increased (27%) their residence time. Under the studied conditions, the atrial geometry plays a major role in the development of intraventricular flow patterns. A reliable prediction of blood flow dynamics and consequently thrombosis risk analysis within the ventricle requires the consideration of the LA in computational simulations.
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Affiliation(s)
- Mojgan Ghodrati
- Center for Medical Physics and Biomedical Engineering, 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.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Alexander Maurer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Thananya Khienwad
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Daniel Zimpfer
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Dietrich Beitzke
- Department of Biomedical Imaging and Image guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Francesco Zonta
- Institute of Fluid Dynamics and Heat Transfer, Technical 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
| | - Heinrich Schima
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.,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
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Martinolli M, Biasetti J, Zonca S, Polverelli L, Vergara C. Extended finite element method for fluid-structure interaction in wave membrane blood pump. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3467. [PMID: 33884770 DOI: 10.1002/cnm.3467] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 03/06/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
Numerical simulations of cardiac blood pump systems are integral to the optimization of device design, hydraulic performance and hemocompatibility. In wave membrane blood pumps, blood propulsion arises from the wave propagation along an oscillating immersed membrane, which generates small pockets of fluid that are pushed towards the outlet against an adverse pressure gradient. We studied the Fluid-Structure Interaction between the oscillating membrane and the blood flow via three-dimensional simulations using the Extended Finite Element Method (XFEM), an unfitted numerical technique that avoids remeshing by using a fluid fixed mesh. Our three-dimensional numerical simulations in a realistic pump geometry highlighted, for the first time in this field of application, that XFEM is a reliable strategy to handle complex industrial problems. Moreover, they showed the role of the membrane deformation in promoting a blood flow towards the outlet despite an adverse pressure gradient. We also simulated the pump system at different pressure conditions and we validated the numerical results against in-vitro experimental data.
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Affiliation(s)
- Marco Martinolli
- MOX, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | | | - Stefano Zonca
- MOX, Dipartimento di Matematica, Politecnico di Milano, Milan, Italy
| | | | - Christian Vergara
- LaBS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Milan, Italy
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Hugenroth K, Neidlin M, Engelmann UM, Kaufmann TAS, Steinseifer U, Heilmann T. Tipless transseptal cannula concept combines improved hemodynamic properties and risk-reduced placement: An in silico proof-of-concept. Artif Organs 2021; 45:1024-1035. [PMID: 33851427 DOI: 10.1111/aor.13964] [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: 11/30/2020] [Revised: 03/17/2021] [Accepted: 04/06/2021] [Indexed: 11/30/2022]
Abstract
As a leading cause of death worldwide, heart failure is a serious medical condition in which many critically ill patients require temporary mechanical circulatory support (MCS) as a bridge-to-recovery or bridge-to-decision. In many cases, the TandemHeart system is used to unload the left heart by draining blood from the left atrium (LA) to the femoral artery via a transseptal multistage cannula. However, even though the correct positioning of the cannula is crucial for a safe treatment, the long cannula tip currently used in transseptal cannulas complicates positioning, making the cannula vulnerable to displacement during MCS. To overcome these limitations, we propose the development of a new tipless transseptal cannula with improved hemodynamic properties. We discuss the tipless cannula concept by comparing it to the common multistage cannula concept using computational fluid dynamics simulations and assess the flow field in the LA, the wall shear stresses (WSS), and the pressure loss. Across the two distinct time points of end-systole and end-diastole and two drainage flow rates of 3.5 and 5.0 L/min, we find a more homogeneous inlet flow pattern for the tipless cannula concept, accompanied by a remarkably reduced area of platelet-activating WSS (up to 10-times smaller area compared to the multistage cannula). Moreover, pressure loss is up to 14.5% lower in the tipless cannula concept, confirming overall improved hemodynamic properties of the tipless cannula concept. Finally, a diameter-dependent study reveals that lower WSS and pressure losses can be further reduced by large-lumen designs for any simulation setting. Overall, our results suggest that a tipless cannula concept remedies the crucial disadvantages of a long-tip multistage cannula by reducing the risk of misplacement, and it furthermore promotes optimized hemodynamics. With this successful proof-of-concept, we underscore the potential for and encourage the realization of further experimental investigations regarding the development of a tipless transseptal cannula for MCS.
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Affiliation(s)
- Kristin Hugenroth
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,enmodes GmbH, Aachen, Germany
| | - Michael Neidlin
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Ulrich M Engelmann
- enmodes GmbH, Aachen, Germany.,Department of Medical Engineering and Applied Mathematics, FH Aachen University of Applied Sciences, Aachen, Germany
| | - Tim A S Kaufmann
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,enmodes GmbH, Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
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Ghodrati M, Maurer A, Schlöglhofer T, Khienwad T, Zimpfer D, Beitzke D, Zonta F, Moscato F, Schima H, Aigner P. The influence of left ventricular assist device inflow cannula position on thrombosis risk. Artif Organs 2020; 44:939-946. [PMID: 32302423 PMCID: PMC7496759 DOI: 10.1111/aor.13705] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/09/2020] [Accepted: 04/08/2020] [Indexed: 12/25/2022]
Abstract
The use of left ventricular assist devices (LVADs) as a treatment method for heart failure patients has been steadily increasing; however, pathological studies showed presence of thrombi around the HeartWare ventricular assist device inflow cannula (IC) in more than 95% of patients after device explantation. Flow fields around the IC might trigger thrombus formation and require further investigation. In this study flow dynamics parameters were evaluated for different patient geometries using computational fluid dynamics (CFD) simulations. Left ventricular (LV) models of two LVAD patients were obtained from CT scans. The LV volumes of Patient 1 (P1) and Patient 2 (P2) were 264 and 114 cm3 with an IC angle of 20° and 9° from the mitral-IC tip axis at the coronal plane. The IC insertion site at the apex was central for P1, whereas it was lateral for P2. Transient CFD simulations were performed over 9 cardiac cycles. The wedge area was defined from the cannula tip to the wall of the LV apex. Mean velocity magnitude and blood stagnation region (volume with mean velocity <5 mm/s) as well as the wall shear stress (WSS) at the IC surface were calculated. Cardiac support resulted in a flow mainly crossing the ventricle from the mitral valve to the LVAD cannula for P2, while the main inflow jet deviated toward the septal wall in P1. Lower WSS at the IC surface and consequently larger stagnation volumes were observed for P2 (P1: 0.17, P2: 0.77 cm3 ). Flow fields around an LVAD cannula can be influenced by many parameters such as LV size, IC angle, and implantation site. Careful consideration of influencing parameters is essential to get reliable evaluations of the apical flow field and its connection to apical thrombus formation. Higher blood washout and lower stagnation were observed for a central implantation of the IC at the apex.
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Affiliation(s)
- Mojgan Ghodrati
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Ludwig Boltzmann Institute for Cardiovascular ResearchViennaAustria
| | - Alexander Maurer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Ludwig Boltzmann Institute for Cardiovascular ResearchViennaAustria
| | - Thomas Schlöglhofer
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Ludwig Boltzmann Institute for Cardiovascular ResearchViennaAustria
- Department for Cardiac SurgeryMedical University of ViennaViennaAustria
| | - Thananya Khienwad
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Daniel Zimpfer
- Department for Cardiac SurgeryMedical University of ViennaViennaAustria
| | - Dietrich Beitzke
- Department of Biomedical Imaging and Image Guided TherapyMedical University of ViennaViennaAustria
| | - Francesco Zonta
- Institute of Fluid Dynamics and Heat TransferTechnical University of ViennaViennaAustria
| | - Francesco Moscato
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Ludwig Boltzmann Institute for Cardiovascular ResearchViennaAustria
| | - Heinrich Schima
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Ludwig Boltzmann Institute for Cardiovascular ResearchViennaAustria
- Department for Cardiac SurgeryMedical University of ViennaViennaAustria
| | - Philipp Aigner
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Ludwig Boltzmann Institute for Cardiovascular ResearchViennaAustria
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Kawamura A, Toda K, Sawa Y. First clinical experience with the double cuff tipless inflow cannula in the EVAHEART left ventricular assist system: Case report. Artif Organs 2019; 44:436-437. [DOI: 10.1111/aor.13588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/01/2019] [Accepted: 10/23/2019] [Indexed: 01/24/2023]
Affiliation(s)
- Ai Kawamura
- Department of Cardiovascular Surgery Osaka University Graduate School of Medicine Suita Japan
| | - Koichi Toda
- Department of Cardiovascular Surgery Osaka University Graduate School of Medicine Suita Japan
| | - Yoshiki Sawa
- Department of Cardiovascular Surgery Osaka University Graduate School of Medicine Suita Japan
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Karimov JH, Polakowski AR, Fukamachi K, Miyamoto T. Progress in mechanical circulatory support: Challenges and opportunities. Artif Organs 2019; 43:818-820. [DOI: 10.1111/aor.13500] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 05/10/2019] [Indexed: 01/18/2023]
Affiliation(s)
- Jamshid H. Karimov
- Department of Biomedical Engineering Lerner Research Institute, Cleveland Clinic Cleveland Ohio
| | - Anthony R. Polakowski
- Department of Biomedical Engineering Lerner Research Institute, Cleveland Clinic Cleveland Ohio
| | - Kiyotaka Fukamachi
- Department of Biomedical Engineering Lerner Research Institute, Cleveland Clinic Cleveland Ohio
| | - Takuma Miyamoto
- Department of Biomedical Engineering Lerner Research Institute, Cleveland Clinic Cleveland Ohio
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May‐Newman K, Montes R, Campos J, Marquez‐Maya N, Vu V, Zebrowski E, Motomura T, Benkowski R. Reducing regional flow stasis and improving intraventricular hemodynamics with a tipless inflow cannula design: An in vitro flow visualization study using the EVAHEART LVAD. Artif Organs 2019; 43:834-848. [DOI: 10.1111/aor.13477] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/11/2019] [Accepted: 04/23/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Karen May‐Newman
- Bioengineering Program, Department of Mechanical Engineering San Diego State University San Diego California
| | - Ricardo Montes
- Bioengineering Program, Department of Mechanical Engineering San Diego State University San Diego California
| | - Josue Campos
- Bioengineering Program, Department of Mechanical Engineering San Diego State University San Diego California
| | - Nikolas Marquez‐Maya
- Bioengineering Program, Department of Mechanical Engineering San Diego State University San Diego California
| | - Vi Vu
- Bioengineering Program, Department of Mechanical Engineering San Diego State University San Diego California
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