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Zhang J, Han D, Chen Z, Wang S, Sun W, Griffith BP, Wu ZJ. Linking Computational Fluid Dynamics Modeling to Device-Induced Platelet Defects in Mechanically Assisted Circulation. ASAIO J 2024:00002480-990000000-00490. [PMID: 38768482 DOI: 10.1097/mat.0000000000002242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024] Open
Abstract
Thrombotic and bleeding events are the most common hematologic complications in patients with mechanically assisted circulation and are closely related to device-induced platelet dysfunction. In this study, we sought to link computational fluid dynamics (CFD) modeling of blood pumps with device-induced platelet defects. Fresh human blood was circulated in circulatory loops with four pumps (CentriMag, HVAD, HeartMate II, and CH-VAD) operated under a total of six clinically representative conditions. Blood samples were collected and analyzed for glycoprotein (GP) IIb/IIIa activation and receptor shedding of GPIbα and GPVI. In parallel, CFD modeling was performed to characterize the blood flow in these pumps. Numerical indices of platelet defects were derived from CFD modeling incorporating previously derived power-law models under constant shear conditions. Numerical results were correlated with experimental results by regression analysis. The results suggested that a scalar shear stress of less than 75 Pa may have limited contribution to platelet damage. The platelet defect indices predicted by the CFD power-law models after excluding shear stress <75 Pa correlated excellently with experimentally measured indices. Although numerical prediction based on the power-law model cannot directly reproduce the experimental data. The power-law model has proven its effectiveness, especially for quantitative comparisons.
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Affiliation(s)
- Jiafeng Zhang
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Dong Han
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Zengsheng Chen
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Shigang Wang
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Wenji Sun
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Bartley P Griffith
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Zhongjun J Wu
- From the Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
- Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, Maryland
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Wu P, Bai Y, Du G, Zhang L, Zhao X. Resistance valves in circulatory loops have a significant impact on in vitro evaluation of blood damage caused by blood pumps: a computational study. Front Physiol 2023; 14:1287207. [PMID: 38098804 PMCID: PMC10720901 DOI: 10.3389/fphys.2023.1287207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/17/2023] [Indexed: 12/17/2023] Open
Abstract
Background: Hemolysis and its complications are major concerns during the clinical application of blood pumps. In-vitro circulatory testing loops have been employed as the key procedure to evaluate the hemolytic and thrombogenic performance of blood pumps during the development phase and before preclinical in-vivo animal studies. Except for the blood damage induced by the pump under test, blood damage induced by loop components such as the resistance valve may affect the accuracy, reproducibility, and intercomparability of test results. Methods: This study quantitatively investigated the impact of the resistance valve on in vitro evaluation of blood damage caused by blood pumps under different operating points. A series of idealized tubing models under the resistance valve with different openings were created. Three pumps - the FDA benchmark pump, the HeartMate 3 LVAD, and the CH-VAD - were involved in hypothetical tests. Eight operating points were chosen to cover a relatively wide spectrum of testing scenarios. Computational fluid dynamics (CFD) simulations of the tubing and pump models were conducted at the same operating points. Results and Conclusion: Overall, hemolysis and platelet activation induced by a typical resistance valve are equivalent to 17%-45% and 14%-60%, respectively, of those induced by the pump itself. Both ratios varied greatly with flow rate, valve opening and pump models. Differences in blood damage levels between different blood pumps or working conditions can be attenuated by up to 45%. Thus, hemolysis and platelet activation induced by the resistance valve significantly affect the accuracy of in-vitro hemocompatibility evaluations of blood pumps. A more accurate and credible method for hemocompatibility evaluations of blood pumps will benefit from these findings.
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Affiliation(s)
- Peng Wu
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, China
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Yuqiao Bai
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Guanting Du
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Liudi Zhang
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Xiangyu Zhao
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
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Zieger B, Schneider D, Brixius SJ, Scherer C, Buchwald A, Trummer G, Czerny M, Beyersdorf F, Busch HJ, Benk C, Pooth JS. Development of an in-vitro model for extracorporeal blood pumps to study the effects of artificial pulsatility on human blood. Front Med (Lausanne) 2023; 10:1237002. [PMID: 37711739 PMCID: PMC10497958 DOI: 10.3389/fmed.2023.1237002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 08/10/2023] [Indexed: 09/16/2023] Open
Abstract
Introduction The application of extracorporeal circulation (ECC) systems is known to be associated with several implications regarding hemolysis, inflammation, and coagulation. In the last years, systems with pulsatile blood flow are increasingly used with the intention to improve hemodynamics in reperfusion. However, their implications on the aforementioned aspects remain largely unknown. To investigate the effects of pulsatility, this ex-vivo study was initiated. Methods Test circuits (primed with human whole blood) were set up in accordance with the recommendations of international standards for in-vitro evaluation of new components and systems of ECC. Diagonal pumps were either set up with non-pulsatile (n = 5, NPG) or pulsatile (n = 5, PG) pump settings and evaluated for 6 h. All analyses were conducted with human whole blood. Blood samples were repeatedly drawn from the test circuits and analyzed regarding free hemoglobin, interleukin 8 (IL-8), platelet aggregation and acquired von Willebrand syndrome (AVWS). Results After 1 h of circulation, a significant coagulation impairment (impaired platelet function and AVWS) was observed in both groups. After 6 h of circulation, increased IL-8 concentrations were measured in both groups (NPG: 0.05 ± 0.03 pg./mL, PG: 0.03 ± 0.01 pg./mL, p = 0.48). Pulsatile pump flow resulted in significantly increased hemolysis after 6 h of circulation (NPG: 37.3 ± 12.4 mg/100 L; PG: 59.6 ± 14.5 mg/100 L; p < 0.05). Conclusion Our results indicate that the coagulative impairment takes place in the early phase of ECC. Pulsatility did not affect the occurrence of AVWS ex-vivo. Prolonged durations of pulsatile pump flow led to increased hemolysis and therefore, its prolonged use should be employed cautiously in clinical practice with appropriate monitoring.
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Affiliation(s)
- Barbara Zieger
- Department of Pediatrics and Adolescent Medicine, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Denise Schneider
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sam Joé Brixius
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christian Scherer
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Armin Buchwald
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Georg Trummer
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martin Czerny
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Friedhelm Beyersdorf
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hans-Jörg Busch
- Department of Emergency Medicine, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christoph Benk
- Department of Cardiovascular Surgery, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jan-Steffen Pooth
- Department of Emergency Medicine, University Medical Centre Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Takahashi H, Kinoshita T, Soh Z, Okahara S, Miyamoto S, Ninomiya S, Tsuji T. Simultaneous Control of Venous Reservoir Level and Arterial Flow Rate in Cardiopulmonary Bypass With a Centrifugal Pump. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE 2023; 11:435-440. [PMID: 37534100 PMCID: PMC10393111 DOI: 10.1109/jtehm.2023.3290951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 08/04/2023]
Abstract
Cardiopulmonary bypass (CPB) is an indispensable technique in cardiac surgery, providing the ability to temporarily replace cardiopulmonary function and create a bloodless surgical field. Traditionally, the operation of CPB systems has depended on the expertise and experience of skilled perfusionists. In particular, simultaneously controlling the arterial and venous occluders is difficult because the blood flow rate and reservoir level both change, and failure may put the patient's life at risk. This study proposes an automatic control system with a two-degree-of-freedom model matching controller nested in an I-PD feedback controller to simultaneously regulate the blood flow rate and reservoir level. CPB operations were performed using glycerin and bovine blood as perfusate to simulate flow-up and flow-down phases. The results confirmed that the arterial blood flow rate followed the manually adjusted target venous blood flow rate, with an error of less than 5.32%, and the reservoir level was maintained, with an error of less than 3.44% from the target reservoir level. Then, we assessed the robustness of the control system against disturbances caused by venting/suction of blood. The resulting flow rate error was 5.95%, and the reservoir level error 2.02%. The accuracy of the proposed system is clinically satisfactory and within the allowable error range of 10% or less, meeting the standards set for perfusionists. Moreover, because of the system's simple configuration, consisting of a camera and notebook PC, the system can easily be integrated with general CPB equipment. This practical design enables seamless adoption in clinical settings. With these advancements, the proposed system represents a significant step towards the automation of CPB.
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Affiliation(s)
- Hidenobu Takahashi
- Department of Medical Science and TechnologyFaculty of Health ScienceHiroshima Kokusai Gakuin UniversityHiroshima739-0321Japan
| | - Takuya Kinoshita
- Graduate School of Advanced Science and EngineeringHiroshima UniversityHigashi-Hiroshima739-8527Japan
| | - Zu Soh
- Graduate School of Advanced Science and EngineeringHiroshima UniversityHigashi-Hiroshima739-8527Japan
| | - Shigeyuki Okahara
- Department of Medical EngineeringFaculty of Health SciencesJunshin Gakuen UniversityFukuoka815-8510Japan
| | - Satoshi Miyamoto
- Clinical EngineeringHiroshima University HospitalHiroshima734-8551Japan
| | - Shinji Ninomiya
- Department of Medical Science and TechnologyFaculty of Health ScienceHiroshima Kokusai Gakuin UniversityHiroshima739-0321Japan
| | - Toshio Tsuji
- Graduate School of Advanced Science and EngineeringHiroshima UniversityHigashi-Hiroshima739-8527Japan
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5
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Li Z, Hu J, Kamberi M, Rapoza RJ. Mechanical stress-induced hemolysis of bovine blood is donor-dependent. Artif Organs 2023; 47:342-351. [PMID: 36134430 DOI: 10.1111/aor.14412] [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: 05/02/2022] [Revised: 07/14/2022] [Accepted: 09/13/2022] [Indexed: 02/03/2023]
Abstract
INTRODUCTION In vitro hemolysis testing is an essential method for assessing the hemolytic potential of blood pumps, but has poor reproducibility. Further investigations are needed to determine the sources and extent of variability and to find a practical way to reduce the variation. METHODS A small volume blood circulating loop driven by a Centrimag pump was established to provide relatively higher hemolysis readouts within a short run time and to be able to sequentially perform multiple repeated hemolysis tests in a working day. RESULTS The repeatability with this system was demonstrated as the %RSD at 4.3% for the NIH or MIH from three repeated tests using the same blood. The bovine blood from different randomly selected donors was tested and gave more than a two-fold difference in NIH results (0.077 vs. 0.032 g/100 L) under the same testing conditions and same pump. This wide variation in hemolysis using bovine blood from different donors happened repeatedly. More importantly, it was observed that the difference in hemolysis test results using the blood drawn from the same donor on multiple days was narrow although the native hematocrits varied. The %RSD of NIH values obtained on five different days were 6.8%, 8.4%, 11.5%, and 7.8% for donor-specific blood from donors 1 to 4, respectively. CONCLUSION The study results indicate that the mechanical stress-induced hemolysis behavior is donor-dependent. It has been also demonstrated that the reproducibility of in vitro hemolysis testing can be improved when the blood drawn from same donor is used.
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Affiliation(s)
- Zengji Li
- Research & Development, Abbott Vascular, Santa Clara, California, USA
| | - Jie Hu
- Research & Development, Abbott Vascular, Santa Clara, California, USA
| | - Marika Kamberi
- Research & Development, Abbott Vascular, Santa Clara, California, USA
| | - Richard J Rapoza
- Research & Development, Abbott Vascular, Santa Clara, California, USA
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6
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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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7
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Sun W, Zhang J, Shah A, Arias K, Berk Z, Griffith BP, Wu ZJ. Neutrophil dysfunction due to continuous mechanical shear exposure in mechanically assisted circulation in vitro. Artif Organs 2022; 46:83-94. [PMID: 34516005 PMCID: PMC8688241 DOI: 10.1111/aor.14068] [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: 06/04/2021] [Revised: 08/10/2021] [Accepted: 09/04/2021] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Leukocytes play an important role in the body's immune system. The aim of this study was to assess alterations in neutrophil phenotype and function in pump-assisted circulation in vitro. METHODS Human blood was circulated for four hours in three circulatory flow loops with a CentriMag blood pump operated at a flow of 4.5 L/min at three rotational speeds (2100, 2800, and 4000 rpm), against three pressure heads (75, 150, and 350 mm Hg), respectively. Blood samples were collected hourly for analyses of neutrophil activation state (Mac-1, CD62L, CD162), neutrophil reactive oxygen species (ROS) production, apoptosis, and neutrophil phagocytosis. RESULTS Activated neutrophils indicated by both Mac-1 expression and decreased surface expression of CD62L and CD162 receptors increased with time in three loops. The highest level of neutrophil activation was observed in the loop with the highest rotational speed. Platelet-neutrophil aggregates (PNAs) progressively increased in two loops with lower rotational speeds. PNAs peaked at one hour after circulation and decreased subsequently in the loop with the highest rotational speed. Neutrophil ROS production dramatically increased at one hour after circulation and decreased subsequently in all three loops with similar levels and trends. Apoptotic neutrophils increased with time in all three loops. Neutrophil phagocytosis capacity in three loops initially elevated at one hour after circulation and decreased subsequently. Apoptosis and altered phagocytosis were dependent on rotational speed. CONCLUSIONS Our study revealed that the pump-assisted circulation induced neutrophil activation, apoptosis, and functional impairment. The alterations were strongly associated with pump operating condition and duration.
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Affiliation(s)
- Wenji Sun
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Aakash Shah
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Katherin Arias
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA,Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, Maryland, USA
| | - Zachary Berk
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Bartley P Griffith
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Zhongjun J Wu
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA,Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, Maryland, USA
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8
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Woelke E, Mager I, Schmitz-Rode T, Steinseifer U, Clauser JC. Validation of a Miniaturized Test Loop for the Assessment of Human Blood Damage by Continuous-Flow Left-Ventricular Assist Devices. Ann Biomed Eng 2021; 49:3165-3175. [PMID: 34431015 PMCID: PMC8671281 DOI: 10.1007/s10439-021-02849-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/04/2021] [Indexed: 11/29/2022]
Abstract
Despite improved hemocompatibility of left-ventricular assist devices (LVADs), assessment of blood damage remains mandatory in preclinical testing as standardized by ASTM-F1841. The most relevant test fluid is fresh, non-pooled human blood, but the limited volume of a standard donation requires significantly smaller loops than those commonly used with animal blood. In a recent study with porcine blood, we verified a miniaturized test loop with only 160 mL for the ASTM-conform paired testing of at least two LVADs and a static reference. Here, we validated this mini test loop for standardized assessment of blood damage with one 450-mL single donation of fresh human blood. Blood damage was assessed for HeartMate 3 and BPX-80 in 9 experiments with heparinized human blood for 6 hours. We analyzed plasma free hemoglobin, von Willebrand factor (vWF) concentration and collagen-binding functionality and calculated indices of hemolysis and vWF-ratios. Overall, we observed less blood damage compared to our previous study; however, the differences in mean indices of hemolysis and in mean normalized vWF-ratio between BPX-80 and HeartMate 3 were consistent for human blood. Thus, our mini test loop proved to be valid for preclinical standardized assessment of blood damage with only 450 mL of fresh human blood.
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Affiliation(s)
- Eva Woelke
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Ilona Mager
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Thomas Schmitz-Rode
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany
| | - Johanna C Clauser
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, Medical Faculty, RWTH Aachen University, Pauwelsstr. 20, 52074, Aachen, Germany.
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9
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Sargent CR, Perkins IL, Kanamarlapudi V, Moriarty C, Ali S. Hemodilution Increases the Susceptibility of Red Blood Cells to Mechanical Shear Stress During In Vitro Hemolysis Testing. ASAIO J 2021; 67:632-641. [PMID: 32947284 DOI: 10.1097/mat.0000000000001280] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The American Society for Testing and Materials (ASTM) F1841 standard for the assessment of hemolysis in blood pumps recommends using phosphate-buffered saline (PBS) for hemodilution to standardize hematocrit (HCT). However, PBS increases red blood cell mechanical fragility and hemolysis. Herein, we investigated diluents and dilutions during in vitro testing to reduce hemodilution bias when assessing hemolysis. Bovine blood was diluted with either PBS or PBS + 4/6 g% bovine serum albumin (BSA) to a 70/90% blood dilution, or to an HCT of 30% ± 2%, and pumped with the CentriMag or RotaFlow under hemodynamic conditions. Separately, bovine and human blood were subjected to ventricular assist device-like shear stress using a vortex. Plasma-free hemoglobin levels, normalized milligram index of hemolysis (mgNIH), and protein concentrations were analyzed. Hemolysis depended on the diluent and final blood concentration. Seventy percent of blood diluted with PBS alone caused significantly greater hemolysis than PBS + 4/6 g% BSA. However, at 90% blood, PBS + 4/6 g% BSA caused significantly greater hemolysis than PBS alone. Hence, a positive correlation between mgNIH and hemodilution was observed with PBS and a negative correlation with PBS + 4g% BSA. PBS alone significantly reduced the total protein concentration. Hemodilution with BSA maintains protein concentration within a physiologic range and reduces bias during hemolysis testing at high blood dilutions. Thus, American Society for Testing and Materials standards could consider including BSA as a diluent, when and as required: where large dilution is required (<83%) use PBS + 4 g% BSA, otherwise use PBS alone.
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Affiliation(s)
- Christian R Sargent
- From the Calon Cardio-Technology Ltd, ILS2, Singleton Park, Swansea, United Kingdom
- Swansea University Medical School, ILS1, Singleton Park, Swansea, United Kingdom
| | - Ina Laura Perkins
- Swansea University Medical School, ILS1, Singleton Park, Swansea, United Kingdom
- R&D, Scandinavian Real Heart AB, Vaesteras, Sweden
| | | | - Christopher Moriarty
- From the Calon Cardio-Technology Ltd, ILS2, Singleton Park, Swansea, United Kingdom
| | - Sabrina Ali
- From the Calon Cardio-Technology Ltd, ILS2, Singleton Park, Swansea, United Kingdom
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10
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Chen Z, Zhang J, Li T, Tran D, Griffith BP, Wu ZJ. The impact of shear stress on device-induced platelet hemostatic dysfunction relevant to thrombosis and bleeding in mechanically assisted circulation. Artif Organs 2019; 44:E201-E213. [PMID: 31849074 DOI: 10.1111/aor.13609] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/21/2022]
Abstract
The aim of this study was to examine the impact of the nonphysiological shear stress (NPSS) on platelet hemostatic function relevant to thrombosis and bleeding in mechanically assisted circulation. Fresh human blood was circulated for four hours in in vitro circulatory flow loops with a CentriMag blood pump operated under a flow rate of 4.5 L/min against three pressure heads (70 mm Hg, 150 mm Hg, and 350 mm Hg) at 2100, 2800, and 4000 rpm, respectively. Hourly blood samples from the CentriMag pump-assisted circulation loops were collected and analyzed for glycoprotein (GP) IIb/IIIa activation and receptor shedding of GPVI and GPIbα on the platelet surface with flow cytometry. Adhesion of platelets to fibrinogen, collagen, and von Willebrand factor (VWF) of the collected blood samples was quantified with fluorescent microscopy. In parallel, mechanical shear stress fields within the CentriMag pump operated under the three conditions were assessed by computational fluid dynamics (CFD) analysis. The experimental results showed that levels of platelet GPIIb/IIIa activation and platelet receptor shedding (GPVI and GPIbα) in the blood increased with increasing the circulation time. The levels of platelet activation and loss of platelet receptors GPVI and GPIbα were consistently higher with higher pressure heads at each increasing hour in the CentriMag pump-assisted circulation. The platelet adhesion on fibrinogen increased with increasing the circulation time for all three CentriMag operating conditions and was correlated well with the level of platelet activation. In contrast, the platelet adhesion on collagen and VWF decreased with increasing the circulation time under all the three conditions and was correlated well with the loss of the receptors GPVI and GPIbα on the platelet surface, respectively. The CFD results showed that levels of shear stresses inside the CentriMag pump under all three operating conditions exceeded the maximum level of shear stress in the normal physiological circulation and were strongly dependent on the pump operating condition. The level of platelet activation and loss of key platelet adhesion receptors (GPVI and GPIbα) were correlated with the level of NPSS generated by the CentriMag pump, respectively. In summary, the level of NPSS associated with pump operating condition is a critical determinant of platelet dysfunction in mechanically assisted circulation.
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Affiliation(s)
- Zengsheng Chen
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Tieluo Li
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Douglas Tran
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Bartley P Griffith
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland
| | - Zhongjun J Wu
- Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland.,Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, Maryland
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11
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Berk ZBK, Zhang J, Chen Z, Tran D, Griffith BP, Wu ZJ. Evaluation of in vitro hemolysis and platelet activation of a newly developed maglev LVAD and two clinically used LVADs with human blood. Artif Organs 2019; 43:870-879. [PMID: 31001834 PMCID: PMC6733624 DOI: 10.1111/aor.13471] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 03/08/2019] [Accepted: 04/11/2019] [Indexed: 12/17/2022]
Abstract
In vitro hemolysis testing remains one of the most important performance measures to judge the hemocompatibility of a left ventricular assist device (LVAD). Clinically relevant operating conditions and appropriate testing blood are essential to infer in vitro data for potential clinical use. This in vitro study was carried out to evaluate and compare the hemolytic performance of a newly developed magnetically levitated (maglev) LVAD (CH-VAD) with two clinically used LVADs (HVAD and HeartMate II (HMII)) using fresh human blood. A small volume (~300 mL) in vitro circulating flow loop was constructed with a LVAD generated flow of 4.5 L/min at the nominal or reported clinical operating speed for each LVAD. The blood was circulated in the loop for 4 hours with samples drawn at baseline and hourly. Plasma-free hemoglobin (PFH) concentrations in the hourly blood samples were determined with spectrophotometry. Normalized index of hemolysis (NIH) was calculated to compare the hemolytic performance of the CH-VAD and the two reference LVADs. Platelet activation was measured with flow cytometry. The experimental test for each device was repeated at least 7 times. The data from this study showed that all the three LVADs generated very low hemolysis (NIH <0.01 g/100 L). The CH-VAD was found to have a significantly lower NIH value (0.00135 ± 0.00032 g/100 L) compared to the HVAD (0.00525 ± 0.00183 g/100 L) and the HMII (0.00583 ± 0.00182 g/100 L). No statistically significant difference in device-generated hemolysis was found between the HVAD and the HMII. The level of platelet activation induced by the CH-VAD is significantly lower than those by the HVAD and the HMII. The data suggest that the shear-induced hemolysis and platelet activation of the CH-VAD are acceptable relative to the two LVADs currently in clinical use.
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Affiliation(s)
- Zachary B. K. Berk
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Zengsheng Chen
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Douglas Tran
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Bartley P. Griffith
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Zhongjun J. Wu
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD 20742,USA
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Chen Z, Zhang J, Kareem K, Tran D, Conway RG, Arias K, Griffith BP, Wu ZJ. Device-induced platelet dysfunction in mechanically assisted circulation increases the risks of thrombosis and bleeding. Artif Organs 2019; 43:745-755. [PMID: 30805954 DOI: 10.1111/aor.13445] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/28/2019] [Accepted: 02/21/2019] [Indexed: 12/24/2022]
Abstract
Thrombotic and bleeding complications are the major obstacles for expanding mechanical circulatory support (MCS) beyond the current use. While providing the needed hemodynamic support, those devices can induce damage to blood, particularly to platelets. In this study, we investigated device-induced alteration of three major platelet surface receptors, von Willebrand factor (VWF) and associated hemostatic functions relevant to thrombosis and bleeding. Fresh human whole blood was circulated in an extracorporeal circuit with a clinical rotary blood pump (CentriMag, Abbott, Chicago, IL, USA) under the clinically relevant operating condition for 4 hours. Blood samples were examined every hour for glycoprotein (GP) IIb/IIIa activation and receptor loss of GPVI and GPIbα on the platelet surface with flow cytometry. Soluble P-selectin in hourly collected blood samples was measured by enzyme linked immunosorbent assay to characterize platelet activation. Adhesion of device-injured platelets to fibrinogen, collagen, and VWF was quantified with fluorescent microscopy. Device-induced damage to VWF was characterized with western blotting. The CentriMag blood pump induced progressive platelet activation with blood circulating time. Particularly, GPIIb/IIIa activation increased from 1.1% (Base) to 11% (4 hours) and soluble P-selectin concentration increased from 14.1 ng/mL (Base) to 26.5 ng/mL (4 hours). Those device-activated platelets exhibited increased adhesion capacity to fibrinogen. Concurrently, the CentriMag blood pump caused progressive platelet receptor loss (GPVI and GPIbα) with blood circulating time. Specifically, MFI of the GPVI and GPIbα receptors decreased by 17.2% and 16.1% for the 4-hours sample compared to the baseline samples, respectively. The device-injured platelets exhibited reduced adhesion capacities to collagen and VWF. The high molecular weight multimers (HMWM) of VWF in the blood disappeared within the first hour of the circulation. Thereafter the multimeric patterns of VWF were stable. The change in the VWF multimeric pattern was different from the progressive structural and functional changes of platelets with the circulation time. This study suggested that the CentriMag blood pump could induce two opposite effects on platelets and associated hemostatic functions under a clinically relevant operating condition. The device-altered hemostatic function may contribute to thrombosis and bleeding simultaneously as occurring in patients supported by a rotary blood pump. Device-induced damage of platelets may be an important cause for bleeding in patients supported with rotary blood pump MCS systems relative to device-induced loss of HMWM-VWF.
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Affiliation(s)
- Zengsheng Chen
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kafayat Kareem
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Douglas Tran
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert G Conway
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Katherin Arias
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA.,Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD, USA
| | - Bartley P Griffith
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Zhongjun J Wu
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA.,Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD, USA
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Johnson CA, Woolley JR, Snyder TA, Shankarraman V, Haney EI, Wagner WR. Assessment of Thrombelastography and Platelet Life Span in Ovines. Artif Organs 2018; 42:E427-E434. [PMID: 30252945 DOI: 10.1111/aor.13282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ovines are a common animal model for the study of cardiovascular devices, where consideration of blood biocompatibility is an essential design criterion. In the ovine model, tools to assess blood biocompatibility are limited and continued investigation to identify and apply additional assays is merited. Toward this end, the thrombelastograph, clinically utilized to assess hemostasis, was used to characterize normal ovine parameters. In addition, platelet labeling with biotin was evaluated for its potential applicability to quantify ovine platelet life span. Mean ovine thrombelastograph values were reaction-time: 4.9 min, K-time: 2 min, angle: 64.1°, maximum amplitude: 68.6mm, actual clot strength: 11.9 kd/s, and coagulation index: 1.5. Reaction time was significantly shorter and maximum amplitude, actual clot strength, and coagulation index were all significantly higher when compared to normal human thrombelastograph values suggesting some hypercoagulability of sheep blood. Biotinylation and reinfusion of ovine platelets allowed temporal tracking of the labeled platelet cohort with flow cytometry. These data indicated a mean ovine platelet life span of 188h with a half-life of 84h. The collection of these parameters for normal ovines demonstrates the applicability of these techniques for subsequent studies where cardiovascular devices may be evaluated and provides an indication of normal ovine values for comparison purposes.
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Affiliation(s)
- Carl A Johnson
- Department of Bioengineering, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joshua R Woolley
- Department of Bioengineering, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Venkat Shankarraman
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - William R Wagner
- Department of Bioengineering, Pittsburgh, PA, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA
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Abstract
In this Editor's Review, articles published in 2017 are organized by category and summarized. We provide a brief reflection of the research and progress in artificial organs intended to advance and better human life while providing insight for continued application of these technologies and methods. Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. Peer-reviewed Special Issues this year included contributions from the 12th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion edited by Dr. Akif Undar, Artificial Oxygen Carriers edited by Drs. Akira Kawaguchi and Jan Simoni, the 24th Congress of the International Society for Mechanical Circulatory Support edited by Dr. Toru Masuzawa, Challenges in the Field of Biomedical Devices: A Multidisciplinary Perspective edited by Dr. Vincenzo Piemonte and colleagues and Functional Electrical Stimulation edited by Dr. Winfried Mayr and colleagues. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.
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