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Gil A, Navarro R, Quintero P, Mares A. Transient Performance Analysis of Centrifugal Left Ventricular Assist Devices Coupled With Windkessel Model: Large Eddy Simulations Study on Continuous and Pulsatile Flow Operation. J Biomech Eng 2024; 146:101008. [PMID: 38683061 DOI: 10.1115/1.4065418] [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: 01/16/2024] [Accepted: 04/25/2024] [Indexed: 05/01/2024]
Abstract
Computational fluid dynamics (CFD) simulations are widely used to develop and analyze blood-contacting medical devices such as left ventricular assist devices (LVADs). This work presents an analysis of the transient behavior of two centrifugal LVADs with different designs: HeartWare VAD and HeartMate3. A scale-resolving methodology is followed through Large Eddy Simulations, which allows for the visualization of turbulent structures. The three-dimensional (3D) LVAD models are coupled to a zero-dimensional (0D) 2-element Windkessel model, which accounts for the vascular resistance and compliance of the arterial system downstream of the device. Furthermore, both continuous- and pulsatile-flow operation modes are analyzed. For the pulsatile conditions, the artificial pulse of HeartMate3 is imposed, leading to a larger variation of performance variables in HeartWare VAD than in HeartMate3. Moreover, CFD results of pulsatile-flow simulations are compared to those obtained by accessing the quasi-steady maps of the pumps. The quasi-steady approach is a predictive tool used to provide a preliminary approximation of the pulsatile evolution of flow rate, pressure head, and power, by only imposing a speed pulse and vascular parameters. This preliminary quasi-steady solution can be useful for deciding the characteristics of the pulsatile speed law before running a transient CFD simulation, as the former entails a significant reduction in computational cost in comparison to the latter.
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Affiliation(s)
- Antonio Gil
- Clean Mobility & Thermofluids, Universitat Politècnica de València, Camino de Vera, s/n, València 46022, Spain
| | - Roberto Navarro
- Clean Mobility & Thermofluids, Universitat Politècnica de València, Camino de Vera, s/n, València 46022, Spain
| | - Pedro Quintero
- Clean Mobility & Thermofluids, Universitat Politècnica de València, Camino de Vera, s/n, València 46022, Spain
- Universitat Politècnica de València
| | - Andrea Mares
- Clean Mobility & Thermofluids, Universitat Politècnica de València, Camino de Vera, s/n, València 46022, Spain
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2
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Huang X, Shen Y, Liu Y, Zhang H. Current status and future directions in pediatric ventricular assist device. Heart Fail Rev 2024; 29:769-784. [PMID: 38530587 DOI: 10.1007/s10741-024-10396-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 03/28/2024]
Abstract
A ventricular assist device (VAD) is a form of mechanical circulatory support that uses a mechanical pump to partially or fully take over the function of a failed heart. In recent decades, the VAD has become a crucial option in the treatment of end-stage heart failure in adult patients. However, due to the lack of suitable devices and more complicated patient profiles, this therapeutic approach is still not widely used for pediatric populations. This article reviews the clinically available devices, adverse events, and future directions of design and implementation in pediatric VADs.
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Affiliation(s)
- Xu Huang
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China
- Shanghai Clinical Research Center for Rare Pediatric Diseases, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China
| | - Yi Shen
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China
- Shanghai Clinical Research Center for Rare Pediatric Diseases, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China
| | - Yiwei Liu
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China.
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China.
- Shanghai Clinical Research Center for Rare Pediatric Diseases, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China.
| | - Hao Zhang
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China.
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China.
- Shanghai Clinical Research Center for Rare Pediatric Diseases, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, No. 1678, Dongfang Rd, Pudong District, Shanghai, 200127, China.
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Escher A, Miric S, Thamsen B, Giuffrida R, Schmidt P, Weinhold B, Hübler M, Zimpfer D, Kolar JW, Granegger M. Multiobjective Optimization of Rotodynamic Blood Pumps: The Use Case of a Cavopulmonary Assist Device. ASAIO J 2024:00002480-990000000-00497. [PMID: 38829985 DOI: 10.1097/mat.0000000000002237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Comprehensive optimization of rotodynamic blood pumps (RBPs) requires the consideration of three partially conflicting objectives: size, hemocompatibility, and motor efficiency. Optimizing these individual objectives independently, the potential of multiobjective optimizations often remains untapped. This study aimed at the multiobjective optimization of an RBP for cavopulmonary support accounting for all three objectives simultaneously. Hydraulic and electromagnetic design spaces were characterized using computational fluid dynamics and computational electromagnetics, respectively. Design variables included secondary flow gap widths, impeller diameters, and stator heights. The size objective encompassed the RBP widths and heights, the hemocompatibility objective was a weighted composite measure of well-established metrics, and the motor objective was determined by motor losses. Multiobjective optimization was performed through Pareto analysis. 81 designs were considered, and 21 Pareto-optimal designs were identified. The Pareto analysis indicated that hemocompatibility performance could be improved by 72.4% with a concomitant 1.5% reduction in the baseline pump volume. This, however, entailed an increase in motor losses by 0.2 W, while still meeting design requirements, with maximum local temperature rises remaining below 0.4 K. The multiobjective optimization led to a Pareto front, demonstrating the feasibility to improve hemocompatibility at reduced pump volume, however, at the cost of a diminished yet still acceptable motor performance.
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Affiliation(s)
- Andreas Escher
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Spasoje Miric
- Department of Mechatronics, University of Innsbruck, Innsbruck, Austria
| | - Bente Thamsen
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Rosario Giuffrida
- Power Electronic Systems Laboratory, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Pascal Schmidt
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Benjamin Weinhold
- Power Electronic Systems Laboratory, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Michael Hübler
- Children's Heart Clinic, University Heart & Vascular Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Daniel Zimpfer
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
- Division of Cardiac Surgery, Department of Surgery, Medical University Graz, Graz, Austria
| | - Johann Walter Kolar
- Power Electronic Systems Laboratory, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Marcus Granegger
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
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4
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Bender M, Escher A, Messner B, Rohrich M, Fischer MB, Hametner C, Laufer G, Kertzscher U, Zimpfer D, Jakubek S, Granegger M. An Atraumatic Mock Loop for Realistic Hemocompatibility Assessment of Blood Pumps. IEEE Trans Biomed Eng 2024; 71:1651-1662. [PMID: 38133971 DOI: 10.1109/tbme.2023.3346206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
OBJECTIVE Conventional mock circulatory loops (MCLs) cannot replicate realistic hemodynamic conditions without inducing blood trauma. This constrains in-vitro hemocompatibility examinations of blood pumps to static test loops that do not mimic clinical scenarios. This study aimed at developing an atraumatic MCL based on a hardware-in-the-loop concept (H-MCL) for realistic hemocompatibility assessment. METHODS The H-MCL was designed for 450 ± 50 ml of blood with the polycarbonate reservoirs, the silicone/polyvinyl-chloride tubing, and the blood pump under investigation as the sole blood-contacting components. To account for inherent coupling effects a decoupling pressure control was derived by feedback linearization, whereas the level control was addressed by an optimization task to overcome periodic loss of controllability. The HeartMate 3 was showcased to evaluate the H-MCL's accuracy at typical hemodynamic conditions. To verify the atraumatic properties of the H-MCL, hemolysis (bovine blood, n = 6) was evaluated using the H-MCL in both inactive (static) and active (minor pulsatility) mode, and compared to results achieved in conventional loops. RESULTS Typical hemodynamic scenarios were replicated with marginal coupling effects and root mean square error (RMSE) below 1.74 ± 1.37 mmHg while the fluid level remained within ±4% of its target value. The normalized indices of hemolysis (NIH) for the inactive H-MCL showed no significant differences to conventional loops ( ∆NIH = -1.6 mg/100 L). Further, no significant difference was evident between the active and inactive mode in the H-MCL ( ∆NIH = +0.3 mg/100 L). CONCLUSION AND SIGNIFICANCE Collectively, these findings indicated the H-MCL's potential for in-vitro hemocompatibility assessment of blood pumps within realistic hemodynamic conditions, eliminating inherent setup-related risks for blood trauma.
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Tran P, Tedesco V, Kiang S, Karnik S, Nguyen D, Frazier OH, Fraser KH, Wang Y. Personalized Numerical Cardiovascular Model with Weight Growth for Evaluating Pediatric Left Ventricular Assist Devices: Derivation from an Experimental Mock Circulatory Loop. Ann Biomed Eng 2024; 52:302-317. [PMID: 37777691 DOI: 10.1007/s10439-023-03376-x] [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: 05/10/2023] [Accepted: 09/24/2023] [Indexed: 10/02/2023]
Abstract
Pediatric patients with heart failure have limited treatment options because of a shortage of donor hearts and compatible left ventricular assist devices (LVADs). To address this issue, our group is developing an implantable pediatric LVAD for patients weighing 5-20 kg, capable of accommodating different physiological hemodynamic conditions as patients grow. To evaluate LVAD prototypes across a wide range of conditions, we developed a numerical cardiovascular model, using data from a mock circulatory loop (MCL) and patient-specific elastance functions. The numerical MCL was validated against experimental MCL results, showing good agreement, with differences ranging from 0 to 11%. The numerical model was also tested under left heart failure conditions and showed a worst-case difference of 16%. In an MCL study with a pediatric LVAD, a pediatric dataset was obtained from the experimental MCL and used to tune the numerical MCL. Then, the numerical model simulated LVAD flow by using an HQ curve obtained from the LVAD's impeller. When the numerical MCL was validated against the experimental MCL, hemodynamic differences ranged between 0 and 9%. These findings suggest that the numerical model can replicate various physiological conditions and impeller designs, indicating its potential as a tool for developing and optimizing pediatric LVADs.
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Affiliation(s)
- Phong Tran
- Innovative Device and Engineering Applications Laboratory, Texas Heart Institute, Houston, TX, USA
| | - Victor Tedesco
- Innovative Device and Engineering Applications Laboratory, Texas Heart Institute, Houston, TX, USA
| | - Simon Kiang
- Innovative Device and Engineering Applications Laboratory, Texas Heart Institute, Houston, TX, USA
| | - Shweta Karnik
- Bioengineering Department, Georgia Institute of Technology, Atlanta, GA, USA
| | - David Nguyen
- Innovative Device and Engineering Applications Laboratory, Texas Heart Institute, Houston, TX, USA
| | - O H Frazier
- Innovative Device and Engineering Applications Laboratory, Texas Heart Institute, Houston, TX, USA
| | | | - Yaxin Wang
- Innovative Device and Engineering Applications Laboratory, Texas Heart Institute, Houston, TX, USA.
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6
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Escher A, Thamsen B, Strauch C, Kertzscher U, Zimpfer D, Thamsen PU, Granegger M. In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges. ASAIO J 2023; 69:932-941. [PMID: 37418316 DOI: 10.1097/mat.0000000000002009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2023] Open
Abstract
Computational fluid dynamics (CFD) is a powerful tool for the in-silico evaluation of rotodynamic blood pumps (RBPs). Corresponding validation, however, is typically restricted to easily accessible, global flow quantities. This study showcased the HeartMate 3 (HM3) to identify feasibility and challenges of enhanced in-vitro validation in third-generation RBPs. To enable high-precision acquisition of impeller torques and grant access for optical flow measurements, the HM3 testbench geometry was geometrically modified. These modifications were reproduced in silico , and global flow computations validated along 15 operating conditions. The globally validated flow in the testbench geometry was compared with CFD-simulated flows in the original geometry to assess the impact of the necessary modifications on global and local hydraulic properties. Global hydraulic properties in the testbench geometry were successfully validated (pressure head: r = 0.999, root mean square error [RMSE] = 2.92 mmHg; torque: r = 0.996, RMSE = 0.134 mNm). In-silico comparison with the original geometry demonstrated good agreement ( r > 0.999, relative errors < 11.97%) of global hydraulic properties. Local hydraulic properties (errors up to 81.78%) and hemocopatibility predictions (deviations up to 21.03%), however, were substantially affected by the geometric modifications. Transferability of local flow measures derived on advanced in-vitro testbenches toward original pump designs is challenged by significant local effects associated with the necessary geometrical modifications.
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Affiliation(s)
- Andreas Escher
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Bente Thamsen
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Carsten Strauch
- Department of Fluid System Dynamics, Technische Universität Berlin, Berlin, Germany
| | - Ulrich Kertzscher
- Deutsches Herzzentrum der Charité - Medical Heart Center of Charité and German Heart Institute Berlin, Institute of Computer-assisted Cardiovascular Medicine, Biofluid Mechanics Laboratory, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Daniel Zimpfer
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
- Division of Cardiac Surgery, Department of Surgery, Medical University Graz, Graz, Austria
| | - Paul Uwe Thamsen
- Department of Fluid System Dynamics, Technische Universität Berlin, Berlin, Germany
| | - Marcus Granegger
- From the Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
- Deutsches Herzzentrum der Charité - Medical Heart Center of Charité and German Heart Institute Berlin, Institute of Computer-assisted Cardiovascular Medicine, Biofluid Mechanics Laboratory, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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7
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Gil A, Navarro R, Quintero P, Mares A. Hemocompatibility and hemodynamic comparison of two centrifugal LVADs: HVAD and HeartMate3. Biomech Model Mechanobiol 2023; 22:871-883. [PMID: 36648697 PMCID: PMC10167126 DOI: 10.1007/s10237-022-01686-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/28/2022] [Indexed: 01/18/2023]
Abstract
Mechanical circulatory support using ventricular assist devices is a common technique for treating patients suffering from advanced heart failure. The latest generation of devices is characterized by centrifugal turbopumps which employ magnetic levitation bearings to ensure a gap clearance between moving and static parts. Despite the increasing use of these devices as a destination therapy, several long-term complications still exist regarding their hemocompatibility. The blood damage associated with different pump designs has been investigated profoundly in the literature, while the hemodynamic performance has been hardly considered. This work presents a novel comparison between the two main devices of the latest generation-HVAD and HM3-from both perspectives, hemodynamic performance and blood damage. Computational fluid dynamics simulations are performed to model the considered LVADs, and computational results are compared to experimental measurements of pressure head to validate the model. Enhanced performance and hemocompatibility are detected for HM3 owing to its design incorporating more conventional blades and larger gap clearances.
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Affiliation(s)
- Antonio Gil
- CMT-Motores Térmicos, Universitat Politècnica de València, Camino de Vera, S/N, 46022, Valencia, Spain
| | - Roberto Navarro
- CMT-Motores Térmicos, Universitat Politècnica de València, Camino de Vera, S/N, 46022, Valencia, Spain
| | - Pedro Quintero
- CMT-Motores Térmicos, Universitat Politècnica de València, Camino de Vera, S/N, 46022, Valencia, Spain
| | - Andrea Mares
- CMT-Motores Térmicos, Universitat Politècnica de València, Camino de Vera, S/N, 46022, Valencia, Spain.
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Antaki JF. A Lone Vibration Crying in the Wilderness. ASAIO J 2022; 68:1126-1127. [PMID: 36066354 DOI: 10.1097/mat.0000000000001809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- James F Antaki
- From the Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
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9
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Gil A, Navarro R, Quintero P, Mares A, Pérez M, Montero JA. CFD analysis of the HVAD's hemodynamic performance and blood damage with insight into gap clearance. Biomech Model Mechanobiol 2022; 21:1201-1215. [PMID: 35546646 DOI: 10.1007/s10237-022-01585-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 04/11/2022] [Indexed: 11/26/2022]
Abstract
Mechanical circulatory support using ventricular assist devices has become commonplace in the treatment of patients suffering from advanced stages of heart failure. While blood damage generated by these devices has been evaluated in depth, their hemodynamic performance has been investigated much less. This work presents the analysis of the complete operating map of a left ventricular assist device, in terms of pressure head, power and efficiency. Further investigation into its hemocompatibility is included as well. To achieve these objectives, computational fluid dynamics simulations of a centrifugal blood pump with a wide-blade impeller were performed. Several conditions were considered by varying the rotational speed and volumetric flow rate. Regarding the device's hemocompatibility, blood damage was evaluated by means of the hemolysis index. By relating the hemocompatibility of the device to its hemodynamic performance, the results have demonstrated that the highest hemolysis occurs at low flow rates, corresponding to operating conditions of low efficiency. Both performance and hemocompatibility are affected by the gap clearance. An innovative investigation into the influence of this design parameter has yielded decreased efficiencies and increased hemolysis as the gap clearance is reduced. As a further novelty, pump operating maps were non-dimensionalized to highlight the influence of Reynolds number, which allows their application to any working condition. The pump's operating range places it in the transitional regime between laminar and turbulent, leading to enhanced efficiency for the highest Reynolds number.
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Affiliation(s)
- Antonio Gil
- CMT-Motores Térmicos, Universitat Politècnica de València, Camí de Vera, s/n, 46022, Valencia, Spain
| | - Roberto Navarro
- CMT-Motores Térmicos, Universitat Politècnica de València, Camí de Vera, s/n, 46022, Valencia, Spain
| | - Pedro Quintero
- CMT-Motores Térmicos, Universitat Politècnica de València, Camí de Vera, s/n, 46022, Valencia, Spain
| | - Andrea Mares
- CMT-Motores Térmicos, Universitat Politècnica de València, Camí de Vera, s/n, 46022, Valencia, Spain.
| | - Manuel Pérez
- Servicio de Cirugía Cardíaca, Hospital Universitario La Fe, Avinguda de Fernando Abril Martorell, 106, 46026, Valencia, Spain
| | - Jose Anastasio Montero
- Servicio de Cirugía Cardíaca, Hospital Universitario La Fe, Avinguda de Fernando Abril Martorell, 106, 46026, Valencia, Spain
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10
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Palazzolo T, Hirschhorn M, Garven E, Day S, Stevens RM, Rossano J, Tchantchaleishvili V, Throckmorton AL. Technology Landscape of Pediatric Mechanical Circulatory Support Devices- A Systematic Review 2010-2021. Artif Organs 2022; 46:1475-1490. [PMID: 35357020 PMCID: PMC9256769 DOI: 10.1111/aor.14242] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/17/2022] [Accepted: 03/15/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mechanical circulatory support (MCS) devices, such as ventricular assist devices (VADs) and total artificial hearts (TAHs), have become a vital therapeutic option in the treatment of end-stage heart failure for adult patients. Such therapeutic options continue to be limited for pediatric patients. Clinicians initially adapted or scaled existing adult devices for pediatric patients; however, these adult devices are not designed to support the anatomical structure and varying flow capacities required for this population and are generally operated "off-design", which risks complications such as hemolysis and thrombosis. Devices designed specifically for the pediatric population that seek to address these shortcomings are now emerging and gaining FDA approval. METHODS To analyze the competitive landscape of pediatric MCS devices, we conducted a systematic literature review. Approximately 27 devices were studied in detail: 8 were established or previously approved designs, and 19 were under development (11 VADs, 5 Fontan assist devices, and 3 TAHs). RESULTS Despite significant progress, there is still no pediatric pump technology that satisfies the unique and distinct design constraints and requirements to support pediatric patients, including the wide range of patient sizes, increased cardiovascular demand with growth, and anatomic and physiologic heterogeneity of congenital heart disease. CONCLUSIONS Forward-thinking design solutions are required to overcome these challenges and to ensure the translation of new therapeutic MCS devices for pediatric patients.
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Affiliation(s)
- Thomas Palazzolo
- BioCirc Research Laboratory, School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Matthew Hirschhorn
- BioCirc Research Laboratory, School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Ellen Garven
- BioCirc Research Laboratory, School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Steven Day
- Department of Biomedical Engineering, Kate Gleason College of Engineering, Rochester Institute of Technology, Rochester, NY, USA
| | - Randy M Stevens
- College of Medicine, St. Christopher's Hospital for Children, Drexel University, Philadelphia, PA, USA
| | - Joseph Rossano
- Division of Pediatric Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Vakhtang Tchantchaleishvili
- Division of Cardiac Surgery, Department of Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Amy L Throckmorton
- BioCirc Research Laboratory, School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA, USA
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11
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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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12
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Escher A, Gobel H, Nicolai M, Schloglhofer T, Hubmann EJ, Laufer G, Messner B, Kertzscher U, Zimpfer D, Granegger M. Hemolytic Footprint of Rotodynamic Blood Pumps. IEEE Trans Biomed Eng 2022; 69:2423-2432. [PMID: 35085069 DOI: 10.1109/tbme.2022.3146135] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE In preclinical examinations, rotodynamic blood pumps (RBPs) are predominantly evaluated at design-point conditions. In clinical practice, however, they run at diversified modes of operation. This study aimed at extending current preclinical evaluation of hemolytic profiles in RBPs toward broader, clinically relevant ranges of operation. METHODS Two implantable RBPs the HeartMate 3 (HM3) and the HeartWare Ventricular Assist Device (HVAD) were analyzed at three pump speeds (HM3: 4300, 5600, 7000rpm; HVAD: 1800, 2760, 3600rpm) with three flow rates (1-9L/min) per speed setting. Hemolysis measurements were performed in heparinized bovine blood. The delta free hemoglobin (dfHb) and the normalized index of hemolysis (NIH) served as hemolytic measures. Statistical analysis was performed by multiple comparison of the 9 operating conditions. Moreover, computational fluid dynamics (CFD) was applied to provide mechanistic insights into the interrelation between hydraulics and hemolysis by correlating numerically computed hydraulic losses with in-vitro hemolytic measures. RESULTS In both devices, dfHb increased toward increasing speeds, particularly during low but also during high flow condition. By contrast, in both RBPs magnitudes of NIH were significantly elevated during low flow operation compared to high flow conditions (p<0.0036). Maps of hemolytic metrics revealed morphologically similar trends to in-silico hydraulic losses (r>0.793). CONCLUSIONS While off-design operation is associated with increased hemolytic profiles, the setting of different operating conditions render a preclinical prediction of clinical impact with current hemolysis metrics difficult. SIGNIFICANCE The identified increase in hemolytic measures during episodes of off-design operation is highlighting the need to consider worst-case operation during preclinical examinations.
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13
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von Petersdorff-Campen K, Schmid Daners M. Hemolysis Testing In Vitro: A Review of Challenges and Potential Improvements. ASAIO J 2022; 68:3-13. [PMID: 33989208 DOI: 10.1097/mat.0000000000001454] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Many medical devices such as cardiopulmonary bypass systems, mechanical heart valves, or ventricular assist devices are intended to come into contact with blood flow during use. In vitro hemolysis testing can provide valuable information about the hemocompatibility of prototypes and thus help reduce the number of animal experiments required. Such tests play an important role as research and development tools for objective comparisons of prototypes and devices as well as for the extrapolation of their results to clinical outcomes. Therefore, it is important to explore and provide new ways to improve current practices. In this article, the main challenges of hemolysis testing are described, namely the difficult blood sourcing, the high experimental workload, and the low reproducibility of test results. Several approaches to address the challenges identified are proposed and the respective literature is reviewed. These include the replacement of blood as the "shear-sensitive fluid" by alternative test fluids, the replacement of sparse, manual sampling and blood damage assessment by a continuous and automated monitoring, as well as an analysis of categories and causes of variability in hemolysis test results that may serve as a structural template for future studies.
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Affiliation(s)
- Kai von Petersdorff-Campen
- From the Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
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14
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Strauch C, Escher A, Wulff S, Kertzscher U, Zimpfer D, Thamsen PU, Granegger M. Validation of Numerically Predicted Shear Stress-dependent Dissipative Losses Within a Rotary Blood Pump. ASAIO J 2021; 67:1148-1158. [PMID: 34582408 DOI: 10.1097/mat.0000000000001488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Computational fluid dynamics find widespread application in the development of rotary blood pumps (RBPs). Yet, corresponding simulations rely on shear stress computations that are afflicted with limited resolution while lacking validation. This study aimed at the experimental validation of integral hydraulic properties to analyze global shear stress resolution across the operational range of a novel RBP. Pressure head and impeller torque were numerically predicted based on Unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and validated on a testbench with integrated sensor modalities (flow, pressure, and torque). Validation was performed by linear regression and Bland-Altman analysis across nine operating conditions. In power loss analysis (PLA), in silico hydraulic power losses were derived based on the validated hydraulic quantities and balanced with in silico shear-dependent dissipative power losses. Discrepancies among both terms provided a measure of in silico shear stress resolution. In silico and in vitro data correlated with low discordance in pressure (r = 0.992, RMSE = 1.02 mmHg), torque (r = 0.999, RMSE = 0.034 mNm), and hydraulic power losses (r = 0.990, RMSE = 0.015W). PLA revealed numerically predicted dissipative losses to be up to 34.4% smaller than validated computations of hydraulic losses. This study confirmed the suitability of URANS settings to predict integral hydraulic properties. However, numerical credibility was hampered by lacking resolution of shear-dependent dissipative losses.
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Affiliation(s)
- Carsten Strauch
- From the Department of Fluid System Dynamics, Technische Universität Berlin, Berlin, Germany
| | - Andreas Escher
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.,Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Wulff
- From the Department of Fluid System Dynamics, Technische Universität Berlin, Berlin, Germany
| | - Ulrich Kertzscher
- Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Daniel Zimpfer
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Paul Uwe Thamsen
- From the Department of Fluid System Dynamics, Technische Universität Berlin, Berlin, Germany
| | - Marcus Granegger
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.,Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Ludwig-Boltzmann-Cluster for Cardiovascular Research, Vienna, Austria
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15
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Deshpande S, Alsoufi B. Meeting needs-pushing boundaries: Mechanical circulatory support in children; year in review. J Thorac Cardiovasc Surg 2021; 162:400-404. [PMID: 33994204 DOI: 10.1016/j.jtcvs.2021.04.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/01/2021] [Accepted: 04/06/2021] [Indexed: 10/21/2022]
Affiliation(s)
- Shriprassad Deshpande
- Department of Cardiology and Cardiac Critical Care, Children's National Hospital, Washington, DC
| | - Bahaaldin Alsoufi
- Department of Cardiovascular and Thoracic Surgery, University of Louisville School of Medicine, Norton Children's Hospital, Louisville, Ky.
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16
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Escher A, Strauch C, Hubmann EJ, Hübler M, Bortis D, Thamsen B, Mueller M, Kertzscher U, Thamsen PU, Kolar JW, Zimpfer D, Granegger M. A Cavopulmonary Assist Device for Long-Term Therapy of Fontan Patients. Semin Thorac Cardiovasc Surg 2021; 34:238-248. [PMID: 34166811 DOI: 10.1053/j.semtcvs.2021.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 06/04/2021] [Indexed: 12/22/2022]
Abstract
Treatment of univentricular hearts remains restricted to palliative surgical corrections (Fontan pathway). The established Fontan circulation lacks a subpulmonary pressure source and is commonly accompanied by progressively declining hemodynamics. A novel cavopulmonary assist device (CPAD) may hold the potential for improved therapeutic management of Fontan patients by chronic restoration of biventricular equivalency. This study aimed at translating clinical objectives toward a functional CPAD with preclinical proof regarding hydraulic performance, hemocompatibility and electric power consumption. A prototype composed of hemocompatible titanium components, ceramic bearings, electric motors, and corresponding drive unit was manufactured for preclinical benchtop analysis: hydraulic performance in general and hemocompatibility characteristics in particular were analyzed in-silico (computational fluid dynamics) and validated in-vitro. The CPAD's power consumption was recorded across the entire operational range. The CPAD delivered pressure step-ups across a comprehensive operational range (0-10 L/min, 0-50 mm Hg) with electric power consumption below 1.5 W within the main operating range. In-vitro hemolysis experiments (N = 3) indicated a normalized index of hemolysis of 3.8 ± 1.6 mg/100 L during design point operation (2500 rpm, 4 L/min). Preclinical investigations revealed the CPAD's potential for low traumatic and thrombogenic support of a heterogeneous Fontan population (pediatric and adult) with potentially accompanying secondary disorders (e.g., elevated pulmonary vascular resistance or systemic ventricular insufficiency) at distinct physical activities. The low power consumption implied adequate settings for a small, fully implantable system with transcutaneous energy transfer. The successful preclinical proof provides the rationale for acute and chronic in-vivo trials aiming at the confirmation of laboratory findings and verification of hemodynamic benefit.
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Affiliation(s)
- Andreas Escher
- Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany; Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Carsten Strauch
- Fachgebiet für Fluidsystemdynamik, Technische Universität Berlin, Berlin, Germany
| | - Emanuel J Hubmann
- Power Electronic Systems Laboratory, ETH Zurich, Zurich, Switzerland
| | - Michael Hübler
- University Heart & Vascular Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dominik Bortis
- Power Electronic Systems Laboratory, ETH Zurich, Zurich, Switzerland
| | - Bente Thamsen
- Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marc Mueller
- Institute for Multiphase Processes, Leibniz University Hannover, Hannover, Germany
| | - Ulrich Kertzscher
- Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Paul U Thamsen
- Fachgebiet für Fluidsystemdynamik, Technische Universität Berlin, Berlin, Germany
| | - Johann W Kolar
- Power Electronic Systems Laboratory, ETH Zurich, Zurich, Switzerland
| | - Daniel Zimpfer
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Marcus Granegger
- Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany; Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.
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17
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Granegger M, Schlöglhofer T, Riebandt J, Schlager G, Skhirtladze-Dworschak K, Kitzmüller E, Michel-Behnke I, Laufer G, Zimpfer D. Mechanical circulatory support in pediatric patients with biventricular and univentricular hearts. JTCVS OPEN 2021; 6:202-208. [PMID: 36003565 PMCID: PMC9390541 DOI: 10.1016/j.xjon.2021.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 03/01/2021] [Indexed: 11/30/2022]
Abstract
Background Mechanical circulatory support (MCS) in pediatric patients remains challenging because of small body size, limited availability of approved devices, and the variety of etiologies, including biventricular and univentricular physiologies. We report our single-center experience with MCS in pediatric patients in terms of survival and adverse events. Methods Outcome, etiologic, and demographic data of pediatric patients implanted with a long-term MCS device between 2011 and 2019 at the Medical University of Vienna were retrospectively collected and analyzed. Overall survival and freedom of treatment-related adverse events at 1 year were investigated by Kaplan–Meier analyses and stratified for circulation (biventricular vs univentricular), age group (<6 years vs >6 years), and pump technology (pulsatile ventricular assist device [p-VAD] vs continuous flow pump [cf-VAD]). Results One-year survival of all 33 pediatric patients (median, 4 years; interquartile range, 0-13 years) was 73%, with a tendency toward better outcomes in patients with biventricular circulation than in those with univentricular circulation (80%; n = 25 vs 50%; n = 8; P = .063). The trends toward better survival probability in older patients and in patients with cf-VADs did not reach statistical significance (63.2% vs 85.7%; P = .165 and 82.4% vs 62.5%; P = .179, respectively). Freedom from adverse events was higher in older patients (57.1% vs 5.6%; P < .001) and in the cf-VAD group (52.9% vs 0%; P < .001), with pump thrombosis as the main discriminator. Conclusions MCS is a promising therapy for a broad spectrum of pediatric patients, irrespective of heart failure etiology, age, and pump type. With increasing experience, improved devices, and patient selection, MCS may become a valuable treatment option for patients with univentricular hearts.
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Affiliation(s)
- Marcus Granegger
- Department of Cardiac Surgery, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
- Ludwig–Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Address for reprints: Marcus Granegger, PhD, Department of Cardiac Surgery, Pediatric Heart Center Vienna, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
| | - Thomas Schlöglhofer
- Department of Cardiac Surgery, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
- Ludwig–Boltzmann Institute for Cardiovascular Research, Vienna, Austria
| | - Julia Riebandt
- Department of Cardiac Surgery, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Gerald Schlager
- Division of Neonatology, Pediatric Intensive Care, and Neuropediatrics, Medical University of Vienna, Vienna, Austria
| | - Keso Skhirtladze-Dworschak
- Department of Anaesthesia, Intensive Care Medicine, and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Erwin Kitzmüller
- Division of Pediatric Cardiology, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Ina Michel-Behnke
- Division of Pediatric Cardiology, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Günther Laufer
- Department of Cardiac Surgery, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
| | - Daniel Zimpfer
- Department of Cardiac Surgery, Pediatric Heart Center Vienna, Medical University of Vienna, Vienna, Austria
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18
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In vitro Hemocompatibility Evaluation of the HeartWare Ventricular Assist Device Under Systemic, Pediatric and Pulmonary Support Conditions. ASAIO J 2021; 67:270-275. [PMID: 33627600 DOI: 10.1097/mat.0000000000001222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The development of adult use right ventricular assist devices (RVADs) and pediatric left ventricular assist devices (pediatric LVADs) have significantly lagged behind compared to adult use left ventricular assist devices (LVADs). The HeartWare ventricular assist device (HVAD) intended to be used for adult's systemic support, is increasingly used off-label for adult pulmonary and pediatric systemic support. Due to different hemodynamics and physiology, however, the HVAD's hemocompatibility profiles can be drastically different when used in adult pulmonary circulation or in children, compared to its intended usage state, which could have a direct clinical and developmental relevance. Taking these considerations in mind, we sought to conduct in vitro hemocompatibility testing of HVAD in adult systemic, pediatric systemic and adult pulmonary support conditions. Two HVADs coupled to custom-built blood circulation loops were tested for 6 hours using bovine blood at 37°C under adult systemic, pediatric systemic, and adult pulmonary flow conditions (flow rate = 5.0, 2.5, and 4.5 L/min; differential pressure = 100, 69, and 20 mm Hg, respectively). Normalized index of hemolysis for adult systemic, pediatric systemic, and adult pulmonary conditions were 0.0083, 0.0039, and 0.0017 g/100 L, respectively. No significant difference was seen in platelet activation for these given conditions. High molecular weight von Willebrand factor multimer degradation was evident in all conditions (p < 0.05). In conclusion, alterations in the usage mode produce substantial differences in hemocompatibility of the HVAD. These findings would not only have clinical relevance but will also facilitate future adult use RVAD and pediatric LVAD development.
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19
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Complications in children with ventricular assist devices: systematic review and meta-analyses. Heart Fail Rev 2021; 27:903-913. [PMID: 33661404 DOI: 10.1007/s10741-021-10093-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/23/2021] [Indexed: 10/22/2022]
Abstract
Heart failure is a significant cause of mortality in children with cardiovascular diseases. Treatment of heart failure depends on patients' symptoms, age, and severity of their condition, with heart transplantation required when other treatments are unsuccessful. However, due to lack of fitting donor organs, many patients are left untreated, or their transplant is delayed. In these patients, ventricular assist devices (VADs) are used to bridge to heart transplant. However, VAD support presents various complications in patients. The aim of this study was to compile, review, and analyse the studies reporting risk factors and aetiologies of complications of VAD support in children. Random effect risk ratios (RR) with 95% confidence intervals were calculated to analyse relative risk of thrombosis (RR = 3.53 [1.04, 12.06] I2 = 0% P = 0.04), neurological problems (RR = 0.95 [0.29, 3.15] I2 = 53% P = 0.93), infection (RR = 0.31 [0.05, 2.03] I2 = 86% P = 0.22), bleeding (RR = 2.57 [0.76, 8.66] I2 = 0% P = 0.13), and mortality (RR = 2.20 [1.36, 3.55] I2 = 0% P = 0.001) under pulsatile-flow and continuous-flow VAD support, relative risk of mortality (RR = 0.45 [0.15, 1.37] I2 = 36% P = 0.16) under left VAD and biVAD support, relative risk of thrombosis (RR = 1.72 [0.46, 6.44] I2 = 0% P = 0.42), infection (RR = 1.77 [0.10, 32.24] I2 = 46% P = 0.70) and mortality (RR = 0.92 [0.14, 6.28] I2 = 45% P = 0.93) in children with body surface area < 1.2 m2 and > 1.2 m2 under VAD support, relative risk of mortality in children supported with VAD and diagnosed with cardiomyopathy and congenital heart diseases (RR = 1.31 [0.10, 16.61] I2 = 73% P = 0.84), and cardiomyopathy and myocarditis (RR = 0.91 [0.13, 6.24] I2 = 58% P = 0.92). Meta-analyses results show that further research is necessary to reduce complications under VAD support.
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20
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Schöps M, Groß-Hardt SH, Schmitz-Rode T, Steinseifer U, Brodie D, Clauser JC, Karagiannidis C. Hemolysis at low blood flow rates: in-vitro and in-silico evaluation of a centrifugal blood pump. J Transl Med 2021; 19:2. [PMID: 33402176 PMCID: PMC7784380 DOI: 10.1186/s12967-020-02599-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/30/2020] [Indexed: 01/03/2023] Open
Abstract
Background Treating severe forms of the acute respiratory distress syndrome and cardiac failure, extracorporeal membrane oxygenation (ECMO) has become an established therapeutic option. Neonatal or pediatric patients receiving ECMO, and patients undergoing extracorporeal CO2 removal (ECCO2R) represent low-flow applications of the technology, requiring lower blood flow than conventional ECMO. Centrifugal blood pumps as a core element of modern ECMO therapy present favorable operating characteristics in the high blood flow range (4 L/min–8 L/min). However, during low-flow applications in the range of 0.5 L/min–2 L/min, adverse events such as increased hemolysis, platelet activation and bleeding complications are reported frequently. Methods In this study, the hemolysis of the centrifugal pump DP3 is evaluated both in vitro and in silico, comparing the low-flow operation at 1 L/min to the high-flow operation at 4 L/min. Results Increased hemolysis occurs at low-flow, both in vitro and in silico. The in-vitro experiments present a sixfold higher relative increased hemolysis at low-flow. Compared to high-flow operation, a more than 3.5-fold increase in blood recirculation within the pump head can be observed in the low-flow range in silico. Conclusions This study highlights the underappreciated hemolysis in centrifugal pumps within the low-flow range, i.e. during pediatric ECMO or ECCO2R treatment. The in-vitro results of hemolysis and the in-silico computational fluid dynamic simulations of flow paths within the pumps raise awareness about blood damage that occurs when using centrifugal pumps at low-flow operating points. These findings underline the urgent need for a specific pump optimized for low-flow treatment. Due to the inherent problems of available centrifugal pumps in the low-flow range, clinicians should use the current centrifugal pumps with caution, alternatively other pumping principles such as positive displacement pumps may be discussed in the future.![]()
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Affiliation(s)
- Malte Schöps
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Pauwelstrasse 20, 52074, Aachen, Germany.
| | - Sascha H Groß-Hardt
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Pauwelstrasse 20, 52074, Aachen, Germany
| | - Thomas Schmitz-Rode
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Pauwelstrasse 20, 52074, Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Pauwelstrasse 20, 52074, Aachen, Germany
| | - Daniel Brodie
- Center for Acute Respiratory Failure, Columbia University College of Physicians and Surgeons/NewYork-Presbyterian Hospital, New York, NY, USA
| | - Johanna C Clauser
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Medical Faculty, RWTH Aachen University, Pauwelstrasse 20, 52074, Aachen, Germany
| | - Christian Karagiannidis
- Department of Pneumology and Critical Care Medicine, Cologne-Merheim Hospital, ARDS and ECMO Centre, Kliniken der Stadt Köln GmbH, Witten/Herdecke University Hospital, Ostmerheimer Strasse 200, 51109, Cologne, Germany
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21
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Kuck L, Simmonds MJ, Chan CHH, Pauls JP, Tansley GD, Feldmann F, McNamee AP. Ex vivo assessment of erythrocyte tolerance to the HeartWare ventricular assist device operated in three discrete configurations. Artif Organs 2020; 45:E146-E157. [PMID: 33236358 DOI: 10.1111/aor.13877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/11/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022]
Abstract
Despite technological advances in ventricular assist devices (VADs) to treat end-stage heart failure, hemocompatibility remains a constant concern, with supraphysiological shear stresses an unavoidable reality with clinical use. Given that impeller rotational speed is related to the instantaneous shear within the pump housing, it is plausible that the modulation of pump speed may regulate peak mechanical shear stresses and thus ameliorate blood damage. The present study investigated the hemocompatibility of the HeartWare HVAD in three configurations typical of clinical applications: standard systemic support left VAD (LVAD), pediatric support LVAD, and pulmonary support right VAD (RVAD) conditions. Two ex vivo mock circulation blood loops were constructed using explanted HVADs, in which pump speed and external loop resistance were manipulated to reflect the flow rates and differential pressures reported in configurations for standard adult LVAD (at 3150 rev⸱min-1 ), pediatric LVAD (at 2400 rev⸱min-1 ), and adult RVAD (at 1900 rev⸱min-1 ). Using bovine blood, the mock circulation blood loops were tested at 37°C over a period of 6 hours (consistent with ASTM F1841-97) and compared with static control. Hemocompatibility assessments were conducted for each test condition, examining hematology, hemolysis (absolute and normalized index), osmotic fragility, and blood viscosity. Regardless of configuration, continuous exposure of blood to the VAD over the 6-hour period significantly altered hematological and rheological blood parameters, and induced increased hemolysis when compared with a static control sample. Comparison of the three operational VAD configurations identified that the adult LVAD condition-associated with the highest pump speed, flow rate, and differential pressure across the pump-resulted in increased normalized hemolysis index (NIH; 0.07) when compared with the lower pump speed "off-label" counterparts (NIH of 0.04 in pediatric LVAD and 0.01 in adult RVAD configurations). After normalizing blood residence times between configurations, pump speed was identified as the primary determinant of accumulated blood damage; plausibly, blood damage could be limited by restricting pump speed to the minimum required to support matched cardiac output, but not beyond.
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Affiliation(s)
- Lennart Kuck
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Michael J Simmonds
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Chris Hoi Houng Chan
- School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Jo P Pauls
- School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Geoff D Tansley
- School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia
| | - Friederike Feldmann
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Antony P McNamee
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
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22
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Thrombotic Risk of Rotor Speed Modulation Regimes of Contemporary Centrifugal Continuous-flow Left Ventricular Assist Devices. ASAIO J 2020; 67:737-745. [PMID: 33074865 DOI: 10.1097/mat.0000000000001297] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Contemporary centrifugal continuous-flow left ventricular assist devices (LVADs) incorporate dynamic speed modulation algorithms. Hemocompatibility of these periodic unsteady pump operating conditions has been only partially explored. We evaluated whether speed modulation induces flow alterations associated with detrimental prothrombotic effects. For this aim, we evaluated the thrombogenic profile of the HeartWare ventricular assist device (HVAD) Lavare Cycle (LC) and HeartMate3 (HM3) artificial pulse (AP) via comprehensive numerical evaluation of (i) pump washout, (ii) stagnation zones, (iii) shear stress regimens, and (iv) modeling of platelet activation status via the platelet activity state (PAS) model. Data were compared between different simulated operating scenarios, including: (i) constant rotational speed and pump pressure head, used as reference; (ii) unsteady pump pressure head as induced by cardiac pulsatility; and (iii) unsteady rotor speed modulation of the LC (HVAD) and AP (HM3). Our results show that pump washout did not improve across the different simulated scenarios in neither the HVAD nor the HM3. The LC reduced but did not eliminate flow stagnation (-57%) and did not impact metrics of HVAD platelet activation (median PAS: +0.4%). The AP reduced HM3 flow stagnation by up to 91% but increased prothrombotic shear stress and simulated platelet activation (median PAS: +124%). Our study advances understanding of the pathogenesis of LVAD thrombosis, suggesting mechanistic implications of rotor speed modulation. Our data provide rationale criteria for the future design optimization of next generation LVADs to further reduce hemocompatibility-related adverse events.
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23
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Fahnhorst SE, Beasley G, Goldberg JF, Martinez HR, Ryan KA, Towbin JA, Boston U, Absi M. Novel use of cangrelor in pediatrics: A pilot cohort study demonstrating use in ventricular assist devices. Artif Organs 2020; 45:38-45. [PMID: 33180355 DOI: 10.1111/aor.13782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/19/2020] [Accepted: 07/14/2020] [Indexed: 01/02/2023]
Abstract
Thromboembolic events and bleeding are major sources of morbidity among pediatric patients supported on a ventricular assist device (VAD). Pharmacokinetics and pharmacodynamics of enteral antiplatelet agents are affected and variable due to erratic enteral absorption in end-stage heart failure and VAD circulation. Additionally, 20%-40% of the population are poor metabolizers of clopidogrel, a prodrug, making cangrelor an alternative when antiplatelet therapy is crucial. Cangrelor has been used effectively and safely for short durations in adults during percutaneous coronary interventions, but the use of cangrelor is still under investigation in pediatrics. This case series utilized cangrelor, a novel short-acting, reversible, intravenous P2Y12 platelet inhibitor in managing pediatric patients supported with a VAD. We performed a retrospective, single-center review of patients admitted to a tertiary medical center with end-stage heart failure requiring mechanical circulatory support and concomitant cangrelor administration between January 2019 and March 2020. Platelet function testing, cangrelor dose, bleeding complications, thromboembolic events, and frequency of circuit interventions during the use of cangrelor were recorded. Optimal platelet reactivity, defined as P2Y12 < 180 platelet reaction units (PRU), was measured with serial point-of-care testing (VerifyNow). Seven patients, median age of 4.9 years, met the above criteria. Three patients had a diagnosis of complex congenital heart disease. Four patients had dilated or restrictive cardiomyopathy. All patients were on continuous flow VADs. The median VAD duration was 84.5 days (IQR 61.5-103). The median duration on cangrelor was 43 days (IQR 8-70). The median cangrelor dose to reach the therapeutic threshold was 0.75 μg/kg/min with the mean P2Y12 , while on cangrelor of 164.75 PRU. Bleeding complications included mild gastrointestinal bleeding and hematuria. There was one patient with pump thrombosis requiring intervention. There were no cerebrovascular events while on cangrelor. We report the first successful long-term use of cangrelor in pediatric patients. The reversibility and short half-life of cangrelor make it a feasible antiplatelet agent in selected patients. This data supports the use of cangrelor in children as a viable antiplatelet option; with minimal bleeding complications and no cerebrovascular events demonstrated in this cohort.
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Affiliation(s)
- Sarah E Fahnhorst
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Gary Beasley
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Jason F Goldberg
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Hugo R Martinez
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Kaitlin A Ryan
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Jeffrey A Towbin
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Umar Boston
- Department of Pediatric Cardiothoracic Surgery, Le Bonheur Children's Hospital, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Mohammed Absi
- Division of Pediatric Cardiology, Le Bonheur Children's Hospital, University of Tennessee Health Sciences Center, Memphis, TN, USA
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24
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Butragueño Laiseca L, Estepa Pedregosa L, Sánchez Galindo AC, Santiago Lozano MJ. Hemolysis and methemoglobinemia in a child with left ventricular assist Levitronix PediMag. Int J Artif Organs 2020; 44:68-71. [PMID: 32552341 DOI: 10.1177/0391398820932175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A 5-month-old male was treated with left ventricular assist device due to cardiac failure secondary to dilated cardiomyopathy. The patient developed acute severe intravascular hemolysis with methemoglobinemia and renal failure, related to a mechanical problem due to pump cylinder misalignment. Secondary severe methemoglobinemia has not been previously described in patients undergoing ventricular assist device. Early detection of the signs and symptoms of hemolysis is crucial to prevent further complications.
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Affiliation(s)
- Laura Butragueño Laiseca
- Department of Pediatric Intensive Care, Hospital General Universitario Gregorio Marañon, Madrid, Spain
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25
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Escher A, Choi Y, Callaghan F, Thamsen B, Kertzscher U, Schweiger M, Hübler M, Granegger M. A Valveless Pulsatile Pump for Heart Failure with Preserved Ejection Fraction: Hemo- and Fluid Dynamic Feasibility. Ann Biomed Eng 2020; 48:1821-1836. [PMID: 32232694 PMCID: PMC7280352 DOI: 10.1007/s10439-020-02492-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/15/2020] [Indexed: 01/02/2023]
Abstract
Treatment of heart failure with preserved ejection fraction (HFpEF) remains a major unmet medical need. An implantable valveless pulsatile pump with a single cannula—the CoPulse pump—may provide beneficial hemodynamic support for select HFpEF patients when connected to the failing ventricle. We aimed to demonstrate hemodynamic efficacy and hemocompatible design feasibility for this novel assist device. The hemodynamic effect of the pump was investigated with an in vitro circulatory mock loop and an ex vivo isolated porcine heart model. The hydraulic design was optimized using computational fluid dynamics (CFD), and validated by 4D-flow magnetic resonance imaging (MRI). The pump reduced left atrial pressure (> 27%) and increased cardiac output (> 14%) in vitro. Ex vivo experiments revealed elevated total stroke volume at increased end-systolic volume during pump support. Asymmetric cannula positioning indicated superior washout, decreased stagnation (8.06 mm2 vs. 31.42 mm2), and marginal blood trauma potential with moderate shear stresses (< 24 Pa) in silico. Good agreement in flow velocities was evident among CFD and 4D-flow MRI data (r > 0.76). The CoPulse pump proved hemodynamically effective. Hemocompatibility metrics were comparable to those of a previously reported, typical pulsatile pump with two cannulae. The encouraging in vitro, ex vivo, and hemocompatibility results substantiate further development of the CoPulse pump.
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Affiliation(s)
- Andreas Escher
- Pediatric Cardiovascular Surgery, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany.,Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, Zurich, Switzerland
| | - Young Choi
- Pediatric Cardiovascular Surgery, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Fraser Callaghan
- Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Center for MR Research, University Children's Hospital Zurich, Zurich, Switzerland
| | - Bente Thamsen
- Pediatric Cardiovascular Surgery, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany
| | - Ulrich Kertzscher
- Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany
| | - Martin Schweiger
- Pediatric Cardiovascular Surgery, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Michael Hübler
- Pediatric Cardiovascular Surgery, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Marcus Granegger
- Pediatric Cardiovascular Surgery, Department of Surgery, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland. .,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland. .,Biofluid Mechanics Laboratory, Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany.
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26
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Davies RR. Commentary: Not safe at any flow: The challenges of low-flow pediatric operation of adult continuous-flow ventricular assist devices. J Thorac Cardiovasc Surg 2020; 159:1530-1531. [PMID: 32007248 DOI: 10.1016/j.jtcvs.2019.10.208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 11/19/2022]
Affiliation(s)
- Ryan R Davies
- Department of Cardiovascular and Thoracic Surgery, UT Southwestern Medical Center and Children's Health, Dallas, Tex.
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27
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Commentary: The tortoise and the hare: Does speed matter in pediatric VAD therapy? J Thorac Cardiovasc Surg 2020; 159:1528-1529. [PMID: 31926737 DOI: 10.1016/j.jtcvs.2019.10.207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 11/20/2022]
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