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Li Y, Xi Y, Wang H, Sun A, Wang L, Deng X, Chen Z, Fan Y. Development and validation of a mathematical model for evaluating shear-induced damage of von Willebrand factor. Comput Biol Med 2023; 164:107379. [PMID: 37597407 DOI: 10.1016/j.compbiomed.2023.107379] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/10/2023] [Accepted: 08/14/2023] [Indexed: 08/21/2023]
Abstract
PURPOSE To develop a mathematical model for predicting shear-induced von Willebrand factor (vWF) function modification which can be used to guide ventricular assist devices (VADs) design, and evaluate the damage of high molecular weight multimers (HMWM)-vWF in VAD patients for reducing clinical complications. METHODS Mathematical models were constructed based on three morphological variations (globular vWF, unfolded vWF and degraded vWF) of vWF under shear stress conditions, in which parameters were obtained from previous studies or fitted by experimental data. Different clinical support modes (pediatric vs. adult mode), different VAD operating states (pulsation vs. constant mode) and different clinical VADs (HeartMate II, HeartWare and CentriMag) were utilized to analyze shear-induced damage of HMWM-vWF based on our vWF model. The accuracy and feasibility of the models were evaluated using various experimental and clinical cases, and the biomechanical mechanisms of HMWM-vWF degradation induced by VADs were further explained. RESULTS The mathematical model developed in this study predicted VAD-induced HMWM-vWF degradation with high accuracy (correlation with experimental data r2 > 0.99). The numerical results showed that VAD in the pediatric mode resulted in more HMWM-vWF degradation per unit time and per unit flow rate than in the adult mode. However, the total degradation of HMWM-vWF is less in the pediatric mode than in the adult mode because the pediatric mode has fewer times of blood circulation than the adult mode in the same amount of time. The ratio of HMWM-vWF degradation was lower in the pulsation mode than in the constant mode. This is due to the increased flushing of VADs in the pulsation mode, which avoids prolonged stagnation of blood in high shear regions. This study also found that the design feature, rotor size and volume of the VADs, and the superimposed regions of high shear stress and long residence time inside VADs affect the degradation of HMWM-vWF. The axial flow VADs (HeartMate II) showed higher degradation of HMWM-vWF compared to centrifugal VADs (HeartWare and CentriMag). Compared to fully magnetically suspended VADs (CentriMag), hydrodynamic suspended VADs (HeartWare) produced extremely high degradation of HWMW-vWF in its narrow hydrodynamic clearance. Finally, the study used a mathematical model of HMWM-vWF degradation to interpret the clinical statistics from a biomechanical perspective and found that minimizing the rotating speed of VADs within reasonable limits helps to reduce HWMW-vWF degradation. All predicted conclusions are supported by the experimental and clinical data. CONCLUSION This study provides a validated mathematical model to assess the shear-induced degradation of HMWM-vWF, which can help to evaluate the damage of HMWM-vWF in patients implanted with VADs for reducing clinical complications, and to guide the optimization of VADs for improving hemocompatibility.
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Affiliation(s)
- Yuan Li
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Yifeng Xi
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Hongyu Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Anqiang Sun
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Lizhen Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Xiaoyan Deng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China
| | - Zengsheng Chen
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.
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Li Y, Wang H, Xi Y, Sun A, Wang L, Deng X, Chen Z, Fan Y. A mathematical model for assessing shear induced bleeding risk. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 231:107390. [PMID: 36745955 DOI: 10.1016/j.cmpb.2023.107390] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
PURPOSE The objective of this study is to develop a bleeding risk model for assessing device-induced bleeding risk in patients supported with blood contact medical devices (BCMDs). METHODS The mathematical model for evaluating bleeding risk considers the effects of shear stress on von Willebrand factor (vWF) unfolding, high molecular weight multimers-vWF (HMWM-vWF) degradation, platelet activation and receptor shedding and platelet-vWF binding ability. Functions of the effect of shear stress on the above factors are fitted/employed and solved by the Eulerian transport equation. An axial flow-through Couette device and two clinical VADs which are HeartWare Ventricular Assist Device (HVAD) and HeartMate II (HM II) blood pump were employed to perform the simulation to evaluate platelet receptor shedding (GPIbα and GPIIb/IIIa), loss of HWMW-vWF, platelet-vWF binding ability and bleeding risk for validating the accuracy of our model. RESULTS The platelet-vWF binding ability after being subjected to high shear region in the axial flow-through Couette device predicted by our bleeding model was highly consistent with reported experimental data. As indicated by our CFD simulation results in the axial flow-through Couette device, it can find that an increase in shear stress led to a decrease in the adhesion ability of platelets on vWF, while the binding ability of vWF with platelets first increase and then decrease as shear stress elevates gradually beyond a threshold. The factor of exposure time can enhance the effect of shear stress. Additionally, the shear-induced bleeding risk predicted by our model increases with increasing shear stress and exposure time in an axial flow-through Couette device. As indicated by our numerical model, the bleeding risk in HVAD was higher than HMII, which is highly consistent with the meta-analysis based on clinical statistics. Our simulation investigations in these two clinical VADs also found that HVAD caused a higher rate of platelet receptor shedding and lower damage to HWMW-vWF than HeartMate II. The high shear stress generated in the narrow and turbulent regions of both VADs was the underlying cause of device-induced bleeding. CONCLUSION In this study, the shear-induced bleeding risk predicted by our bleeding model in axial flow-through Couette device and two clinical VADs is consistent or highly correlated with experimental and clinical findings, which proves the accuracy of our bleeding model. Our bleeding model can be used to aid the development of new BCMDs with improved functional characteristics and biocompatibility, and help to reduce risk of device-induced adverse events in patients.
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Affiliation(s)
- Yuan Li
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Hongyu Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Yifeng Xi
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Anqiang Sun
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Lizhen Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Xiaoyan Deng
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Zengsheng Chen
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
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Xu KW, Gao Q, Wan M, Zhang K. Mock circulatory loop applications for testing cardiovascular assist devices and in vitro studies. Front Physiol 2023; 14:1175919. [PMID: 37123281 PMCID: PMC10133581 DOI: 10.3389/fphys.2023.1175919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/03/2023] [Indexed: 05/02/2023] Open
Abstract
The mock circulatory loop (MCL) is an in vitro experimental system that can provide continuous pulsatile flows and simulate different physiological or pathological parameters of the human circulation system. It is of great significance for testing cardiovascular assist device (CAD), which is a type of clinical instrument used to treat cardiovascular disease and alleviate the dilemma of insufficient donor hearts. The MCL installed with different types of CADs can simulate specific conditions of clinical surgery for evaluating the effectiveness and reliability of those CADs under the repeated performance tests and reliability tests. Also, patient-specific cardiovascular models can be employed in the circulation of MCL for targeted pathological study associated with hemodynamics. Therefore, The MCL system has various combinations of different functional units according to its richful applications, which are comprehensively reviewed in the current work. Four types of CADs including prosthetic heart valve (PHV), ventricular assist device (VAD), total artificial heart (TAH) and intra-aortic balloon pump (IABP) applied in MCL experiments are documented and compared in detail. Moreover, MCLs with more complicated structures for achieving advanced functions are further introduced, such as MCL for the pediatric application, MCL with anatomical phantoms and MCL synchronizing multiple circulation systems. By reviewing the constructions and functions of available MCLs, the features of MCLs for different applications are summarized, and directions of developing the MCLs are suggested.
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Affiliation(s)
- Ke-Wei Xu
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China
| | - Qi Gao
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China
- *Correspondence: Qi Gao,
| | - Min Wan
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, Jinan, China
| | - Ke Zhang
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, Jinan, China
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Deconinck SJ, Nix C, Barth S, Bennek-Schöpping E, Rauch A, Schelpe AS, Roose E, Feys HB, Pareyn I, Vandenbulcke A, Muia J, Vandenbriele C, Susen S, Meyns B, Tersteeg C, Jacobs S, De Meyer SF, Vanhoorelbeke K. ADAMTS13 inhibition to treat acquired von Willebrand syndrome during mechanical circulatory support device implantation. J Thromb Haemost 2022; 20:2797-2809. [PMID: 36128768 PMCID: PMC9669188 DOI: 10.1111/jth.15889] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/31/2022] [Accepted: 09/18/2022] [Indexed: 01/13/2023]
Abstract
BACKGROUND Acquired von Willebrand syndrome (aVWS) is common in patients with mechanical circulatory support (MCS) devices. In these patients, the high shear stress in the device leads to increased shear-induced proteolysis of von Willebrand factor (VWF) by A Disintegrin And Metalloprotease with Thrombospondin type 1 repeats, number 13 (ADAMTS13). As a result, the high molecular weight (HMW) VWF multimers are lost, leading to a decreased VWF function and impaired hemostasis that could explain the bleeding complications that are frequently observed in these patients. To counteract this abnormal VWF degradation by ADAMTS13, we developed a novel targeted therapy, using an anti-ADAMTS13 monoclonal antibody (mAb) that inhibits the shear-induced proteolysis of VWF by ADAMTS13. METHODS Human or bovine blood was circulated through in vitro MCS device systems with either inhibitory anti-ADAMTS13 mAb 3H9 or 17C7 (20 μg/ml) or control anti-ADAMTS13 mAb 5C11 or phosphate buffered saline (PBS). VWF multimers and function (collagen binding activity) were determined at different time points. Next, Impella pumps were implanted in calves and the calves were injected with PBS and subsequently treated with mAb 17C7. VWF, ADAMTS13, and blood parameters were determined. RESULTS We demonstrated that blocking ADAMTS13 could prevent the loss of HMW VWF multimers in in vitro MCS device systems. Importantly, our antibody could reverse aVWS in a preclinical Impella-induced aVWS calf model. CONCLUSION Hence, inhibition of ADAMTS13 could become a novel therapeutic strategy to manage aVWS in MCS device patients.
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Affiliation(s)
- Shannen J Deconinck
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Christoph Nix
- Abiomed Europe GmbH, Neuenhofer Weg 3, Aachen, D-52074
| | - Svenja Barth
- Abiomed Europe GmbH, Neuenhofer Weg 3, Aachen, D-52074
| | | | - Antoine Rauch
- University of Lille, INSERM U1011-EGID, Lille, France
- CHU Lille, Hematology Transfusion, Lille, France
| | - An-Sofie Schelpe
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Elien Roose
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Hendrik B Feys
- Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium
- Ghent University, Faculty of Medicine and Health Sciences, Ghent, Belgium
| | - Inge Pareyn
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Aline Vandenbulcke
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Joshua Muia
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma
| | | | - Sophie Susen
- University of Lille, INSERM U1011-EGID, Lille, France
- CHU Lille, Hematology Transfusion, Lille, France
| | - Bart Meyns
- Department of Clinical Cardiac Surgery, University Hospitals Leuven, Belgium
| | - Claudia Tersteeg
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Steven Jacobs
- Department of Clinical Cardiac Surgery, University Hospitals Leuven, Belgium
| | - Simon F De Meyer
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
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Martin AA, Bhat R, Chitlur M. Hemostasis in Pediatric Extracorporeal Life Support: Overview and Challenges. Pediatr Clin North Am 2022; 69:441-464. [PMID: 35667756 DOI: 10.1016/j.pcl.2022.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs) are increasingly used in critically ill children. Despite improvements in mechanical design and clinical management, thromboembolic and hemorrhagic events remain significant causes of morbidity and mortality related to the use of both devices. Choice of anticoagulant agents and assays for monitoring continue to present challenges in management. In this review, we describe the incidence and risk factors for thrombosis and hemorrhage, the different types of anticoagulants currently in use, the assays available for monitoring anticoagulation, and management of thromboembolic and bleeding complications in children on mechanical circulatory support (MCS). We conclude by emphasizing the areas that need further study to minimize the risk for thrombosis and hemorrhage in the use of ECMO and VAD in children.
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Affiliation(s)
- Amarilis A Martin
- Division of Pediatric Critical Care Medicine, Central Michigan University College of Medicine, Children's Hospital of Michigan, Carl's Building Suite 4114, 3901 Beaubien Street, Detroit, MI 48201, USA.
| | - Rukhmi Bhat
- Division of Hematology, Oncology and Stem Cell Transplantation, Northwestern University Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago, Box #30, Chicago, IL 60611, USA
| | - Meera Chitlur
- Wayne State University, Central Michigan University, Hemophilia Treatment Center and Hemostasis Program, Special Coagulation Laboratory, Division of Hematology/Oncology, Children's Hospital of Michigan, 3901 Beaubien Street, Detroit, MI 48201, USA
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6
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(Physiology of Continuous-flow Left Ventricular Assist Device Therapy. Translation of the document prepared by the Czech Society of Cardiology). COR ET VASA 2022. [DOI: 10.33678/cor.2022.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rosenbaum AN, Antaki JF, Behfar A, Villavicencio MA, Stulak J, Kushwaha SS. Physiology of Continuous-Flow Left Ventricular Assist Device Therapy. Compr Physiol 2021; 12:2731-2767. [PMID: 34964115 DOI: 10.1002/cphy.c210016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The expanding use of continuous-flow left ventricular assist devices (CF-LVADs) for end-stage heart failure warrants familiarity with the physiologic interaction of the device with the native circulation. Contemporary devices utilize predominantly centrifugal flow and, to a lesser extent, axial flow rotors that vary with respect to their intrinsic flow characteristics. Flow can be manipulated with adjustments to preload and afterload as in the native heart, and ascertainment of the predicted effects is provided by differential pressure-flow (H-Q) curves or loops. Valvular heart disease, especially aortic regurgitation, may significantly affect adequacy of mechanical support. In contrast, atrioventricular and ventriculoventricular timing is of less certain significance. Although beneficial effects of device therapy are typically seen due to enhanced distal perfusion, unloading of the left ventricle and atrium, and amelioration of secondary pulmonary hypertension, negative effects of CF-LVAD therapy on right ventricular filling and function, through right-sided loading and septal interaction, can make optimization challenging. Additionally, a lack of pulsatile energy provided by CF-LVAD therapy has physiologic consequences for end-organ function and may be responsible for a series of adverse effects. Rheological effects of intravascular pumps, especially shear stress exposure, result in platelet activation and hemolysis, which may result in both thrombotic and hemorrhagic consequences. Development of novel solutions for untoward device-circulatory interactions will facilitate hemodynamic support while mitigating adverse events. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.
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Affiliation(s)
- Andrew N Rosenbaum
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA
| | - James F Antaki
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Atta Behfar
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA.,VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - John Stulak
- Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Sudhir S Kushwaha
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA
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Carroll AH, Dowlati E, Miller C, Felbaum DR. Diagnostic Evaluation and Cervical Spine Surgery in the Setting of a Cardiac Left Ventricular Assist Device: Challenges and a Case Illustration. Cureus 2021; 13:e19571. [PMID: 34926043 PMCID: PMC8671078 DOI: 10.7759/cureus.19571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2021] [Indexed: 11/05/2022] Open
Abstract
Due to incompatibility with magnetic resonance imaging, patients with left ventricular assist devices (LVADs) presenting with pathologies of the spinal soft tissues or neural elements represent diagnostically complex cases. We present a case of a patient undergoing a CT (computed tomography) myelogram and subsequent successful cervical posterior laminectomy. A C1-C2 lateral puncture approach CT myelogram revealed nearly a complete block of contrast movement at the level of the C2-C3 vertebrae concerning a compressive etiology. The cervical lateral approach was chosen based on patient symptomology and concern that contrast dye injected in the lumbar spine would not travel to the region of interest due to altered CSF pulsatility caused by the LVAD device. A C3-C7 posterior laminectomy was then successfully performed. Intra-operatively, however, there was no sign of a compressive lesion, and ultrasound confirmed a decompressed spinal cord. This case highlights the diagnostic challenges of pre-operative evaluation in patients with LVADs in which the efficacy of performing CT myelograms is also questionable due to potential alterations in cerebrospinal fluid movement due to variations in arterial pulsatility due to LVAD physiology.
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Affiliation(s)
- Austin H Carroll
- Department of Neurological Surgery, Georgetown University School of Medicine, Washington DC, USA
| | - Ehsan Dowlati
- Department of Neurological Surgery, MedStar Georgetown University, Washington DC, USA
| | - Charles Miller
- Department of Neurological Surgery, Walter Reed National Military Medical Center, Bethesda, USA
| | - Daniel R Felbaum
- Department of Neurosurgery, MedStar Georgetown University, Washington DC, USA
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Bartoli CR. Pathologic von Willebrand factor degradation is a major contributor to left ventricular assist device-associated bleeding: pathophysiology and evolving clinical management. Ann Cardiothorac Surg 2021; 10:389-392. [PMID: 34159121 DOI: 10.21037/acs-2020-cfmcs-29] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Carlo R Bartoli
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
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Abnormalities in the Von Willebrand-Angiopoietin Axis Contribute to Dysregulated Angiogenesis and Angiodysplasia in Children With a Glenn Circulation. JACC Basic Transl Sci 2021; 6:222-235. [PMID: 33778210 PMCID: PMC7987544 DOI: 10.1016/j.jacbts.2020.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 02/08/2023]
Abstract
Children with a bidirectional superior cavopulmonary connection (Glenn circulation) develop dysregulated angiogenesis and pulmonary angiodysplasia in the form of arteriovenous malformations (AVMs). No targeted therapy exists. The von Willebrand factor (vWF)–angiopoietin axis plays a major role in normal angiogenesis, angiodysplasia, and AVM formation in multiple diseases. vWF and angiopoietin-2 (which destabilizes vessel formation) were abnormal in children with a Glenn circulation versus control children. Within Glenn patients, angiopoietin-1 (which stabilizes vessel formation) and angiogenesis were different in the systemic versus pulmonary circulation. Plasma angiopoietin-1 was lower in the pulmonary circulation of Glenn patients with pulmonary AVMs than Glenn patients without AVMs. In parallel, differences in multiple angiogenic and inflammatory signaling peptides were observed between Glenn patients and controls, which indicated derangements in multiple angiogenic pathways in Glenn patients. These findings support the novel hypothesis that abnormal vWF metabolism and angiopoietin signaling dysregulate angiogenesis and contribute to pulmonary AVM formation in children with a Glenn circulation. The vWF-angiopoietin axis may be a target to correct angiogenic imbalance and reduce pulmonary angiodysplasia in Glenn patients.
Children with a bidirectional superior cavopulmonary (Glenn) circulation develop angiodysplasia and pulmonary arteriovenous malformations (AVMs). The von Willebrand factor (vWF)–angiopoietin axis plays a major role in AVM formation in multiple diseases. We observed derangements in global angiogenic signaling, vWF metabolism, angiopoietins, and in vitro angiogenesis in children with a Glenn circulation versus controls and within Glenn pulmonary versus systemic circulations. These findings support the novel hypothesis that abnormalities in the vWF-angiopoietin axis may dysregulate angiogenesis and contribute to Glenn pulmonary AVMs. The vWF-angiopoietin axis may be a target to correct angiogenic imbalance in Glenn patients, for whom no targeted therapy exists.
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Key Words
- ADAMTS-13, a disintegrin and metalloproteinase thrombospondin (motif) #13
- AVM, arteriovenous malformation
- EBM, endothelial basal media
- EGM, endothelial growth media
- Glenn
- HUVEC, human umbilical vein endothelial cell
- IVC, inferior vena cava
- LVAD, left ventricular assist device
- PA, pulmonary artery
- SVC, superior vena cava
- angiogenesis
- angiopoietin
- arteriovenous malformation
- vWF, von Willebrand factor
- von Willebrand factor
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Mei X, Zhong M, Ge W, Zhang L. Mathematical models for shear-induced blood damage based on vortex platform. Int J Artif Organs 2021; 45:397-403. [PMID: 33740880 DOI: 10.1177/03913988211003587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Non-physiological shear stress in Ventricular Assist Device (VAD) is considered to be an important trigger of blood damage, which has become the biggest shackle for clinical application. The researches on blood damage in literature were limited to qualitative but did not make much quantitative analysis. The purpose of this study was to investigate the quantitative influence of two flow-dependent parameters: shear stress (rotational speed) and exposure time on the shear-induced damage of red blood cells and von Willebrand Factor (vWF). A vortex blood-shearing platform was constructed to conduct in vitro experiments. Free hemoglobin assay and vWF molecular weight analysis were then performed on the sheared blood samples. MATLAB was used for regression fitting of original experimental data. The quantitative correlations between the hemolysis index, the degradation of high molecular weight vWF and the two flow-dependent parameters were found both following the power law model. The mathematic models indicated that the sensitivity of blood damage on red blood cells and vWF to exposure time was both greater than that of shear stress. Besides, the damage of vWF was more serious than that of red blood cells at the same flow condition. The models could be used to predict blood damage in blood-contacting medical devices, especially for the slow even stagnant blood flow regions in VAD, thus may provide useful guidance for VAD development and improvement. It also indicated that the vortex platform can be used to study the law of blood damage for the simple structure and easy operation.
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Affiliation(s)
- Xu Mei
- Artificial Organ Laboratory, Bio-manufacturing Research Centre, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Min Zhong
- Artificial Organ Laboratory, Bio-manufacturing Research Centre, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Wanning Ge
- Artificial Organ Laboratory, Bio-manufacturing Research Centre, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Liudi Zhang
- Artificial Organ Laboratory, Bio-manufacturing Research Centre, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
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Carroll AH, Ramirez MP, Dowlati E, Mueller KB, Borazjani A, Chang JJ, Felbaum DR. Management of Intracranial Hemorrhage in Patients with a Left Ventricular Assist Device: A Systematic Review and Meta-Analysis. J Stroke Cerebrovasc Dis 2020; 30:105501. [PMID: 33271486 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/12/2020] [Accepted: 11/21/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Intracranial hemorrhage (ICH) has been reported to occur in up to 23% of patients with left ventricular assist devices (LVADs). Currently, limited data exists to guide neurosurgical management strategies to optimize outcomes in patients with an LVAD who develop ICH. METHODS A systematic review and meta-analysis of the literature was performed to evaluate the mortality rate in these patients following medical and/or surgical management and to evaluate antithrombotic reversal and resumption strategies after hemorrhage. RESULTS 17 studies reporting on 3869 LVAD patients and 545 intracranial hemorrhages spanning investigative periods from 1996 to 2019 were included. The rate of ICH in LVAD patients was 10.6% (411/3869) with 58.6% (231/394) being intraparenchymal hemorrhage (IPH), 23.6% (93/394) subarachnoid hemorrhage (SAH), and 15.5% (61/394) subdural hemorrhage (SDH). Total mortality rates for surgical management 65.6% (40/61) differed from medical management at 45.2% (109/241). There was an increased relative risk of mortality (RR=1.45, 95% CI: 1.10-1.91, p = 0.01) for ICH patients undergoing surgical intervention. The hemorrhage subtype most frequently managed with anticoagulation reversal was IPH 81.8% (63/77), followed by SDH 52.2% (12/23), and SAH 39.1% (18/46). Mean number of days until antithrombotic resumption ranged from 6 to 10.5 days. CONCLUSION Outcomes remain poor, specifically for those undergoing surgery. As experience with this population increases, prospective studies are warranted to contribute to management and prognostication .
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Affiliation(s)
| | | | - Ehsan Dowlati
- Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, D.C., USA.
| | - Kyle B Mueller
- Department of Neurosurgery, Rhode Island Hospital, Warren Alpert Medical School at Brown University, Providence, R.I., USA
| | - Ali Borazjani
- Georgetown University School of Medicine, Washington, D.C., USA
| | - Jason J Chang
- Department of Critical Care Medicine, MedStar Washington Hospital Center, Washington D.C., USA
| | - Daniel R Felbaum
- Department of Neurosurgery, MedStar Washington Hospital Center, Washington, D.C., USA; Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, D.C., USA
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Bartoli CR, Kang J, Motomura T. Decreased RPM reduces von Willebrand factor degradation with the EVAHEART LVAS: implications for device-specific LVAD management. J Card Surg 2020; 35:1477-1483. [PMID: 32652785 DOI: 10.1111/jocs.14620] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/16/2020] [Accepted: 04/29/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Continuous-flow left ventricular assist devices (LVADs) produces supraphysiologic shear stress that causes von Willebrand factor (VWF) degradation and a bleeding diathesis. Reduction of revolutions per minute (RPM) with axial-flow LVADs does not decrease shear stress enough to reduce VWF degradation and bleeding. However, it is unknown if RPM reduction with centrifugal flow LVADs may minimize VWF degradation. We tested the hypothesis that RPM reduction preserves VWF multimers in the centrifugal-flow EVAHEART left ventricular assist system (LVAS), which is designed to minimize shear stress and blood trauma. METHODS Whole blood samples were collected from humans (n = 28). Blood was circulated in ex vivo mock circulatory loops for 6 hours with an EVAHEART LVAS at 2300 (n = 12), 2100 (n = 8), or 1800 RPM (n = 8). Immunoblotting was used to resolve and quantify VWF multimers and degradation fragments. RESULTS RPM reduction from 2300 to 2100 to 1800 RPM significantly decreased EVAHEART blood flow from 5.8 ± 0.4 to 4.3 ± 0.6 to 4.1 ± 0.5 L/min (analysis of variance [ANOVA], P = .03). RPM reduction protected VWF from pathologic degradation. At lower RPMs, significantly greater levels of VWF multimers were observed (ANOVA, P = .001). Similarly, at lower RPMs, significantly fewer VWF fragments, a product of VWF degradation, were observed (ANOVA, P = .007). CONCLUSIONS RPM reduction significantly reduced VWF degradation with the centrifugal-flow EVAHEART LVAS, an LVAD specifically designed with low shear stress. Different LVADs have unique hematologic footprints and should be managed with device-specific protocols. Adjustment of RPM to minimize blood trauma while still maintaining physiologic hemodynamics has the potential to decrease complications related to LVAD-associated von Willebrand's disease, such as gastrointestinal bleeding and hemorrhagic stroke.
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Affiliation(s)
- Carlo R Bartoli
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jooeun Kang
- MD-PhD Program, Vanderbilt University, Nashville, Tennessee
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Kobayashi Y, Imai Y, Mizutani S, Higo T, Shiose A, Kashiwazaki H. Opportune Time of Tooth Extraction in Individuals Requiring Ventricular Assist Device Implantation: A Retrospective Cohort Study. J Oral Maxillofac Surg 2020; 78:1921.e1-1921.e9. [PMID: 32574607 DOI: 10.1016/j.joms.2020.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/29/2020] [Accepted: 05/06/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE Individuals with implantable ventricular assist devices (VADs) are at extremely high risk of bleeding, thromboembolism, and infection after undergoing invasive dental procedures. This study aimed to investigate the systemic and local complications of tooth extraction before and after VAD implantation. PATIENTS AND METHODS This retrospective cohort study was conducted at a single center. Oral surgical procedures were performed in patients before and/or after left VAD implantation for bridge-to-heart transplantation between April 2013 and December 2017. In this study, the medical charts of the patients were retrospectively reviewed. Data about pre-extraction complete blood count, coagulation profile, biochemical profile, and incidence of local and systemic complications were compared in patients undergoing tooth extraction before VAD implantation (b-VAD group) versus after VAD implantation (a-VAD group). RESULTS In total, 28 inpatients underwent 36 oral surgical procedures before and/or after VAD implantation. Moreover, 24 tooth extractions were performed in the b-VAD group, and 12 were performed in the a-VAD group. The incidence of post-extraction bleeding was higher in the a-VAD group (P = .001, Mann-Whitney U test), and a significant difference was observed in terms of activated partial thromboplastin time (P = .010, Mann-Whitney U test). Systemic complications associated with VADs included cerebral infarction (n = 2) and driveline infection (n = 1). Post-extraction bleeding was observed within 90 days after VAD implantation in all patients who underwent tooth extraction. CONCLUSIONS The risk of bleeding after tooth extraction was higher in the a-VAD group (67%) than in the b-VAD group (13%). In 3 cases, VAD-related systemic complications developed within a short period after tooth extraction. The extraction management in the b-VAD group could be controlled without causing any problem. Hence, the opportune time of tooth extraction is before VAD implantation.
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Affiliation(s)
- Yoshihiro Kobayashi
- Postgraduate Student, Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan; and Geriatric Dentistry and Perioperative Medicine in Dentistry, Kyushu University Hospital, Fukuoka, Japan
| | - Yuko Imai
- Research Associate, Geriatric Dentistry and Perioperative Medicine in Dentistry, Kyushu University Hospital, Fukuoka, Japan.
| | - Shinsuke Mizutani
- Associate Professor, Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, and Oral Health, Brain Health, Total Health Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Taiki Higo
- Lecturer, Department of Cardiovascular Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Akira Shiose
- Professor, Department of Cardiovascular Surgery, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Haruhiko Kashiwazaki
- Professor, Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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15
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Koycu A, Vural O, Bahcecitapar M, Jafarov S, Beyazpinar G, Beyazpinar DS. Device-related epistaxis risk: continuous-flow left ventricular assist device-supported patients. Eur Arch Otorhinolaryngol 2020; 277:2767-2773. [PMID: 32556786 DOI: 10.1007/s00405-020-06127-z] [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: 04/06/2020] [Accepted: 06/10/2020] [Indexed: 11/27/2022]
Abstract
BACKGROUND The aim of this study was to analyze the effect of device-dependent factors on epistaxis episodes comparing patients supported with a continuous-flow left ventricular assist device (CF-LVAD) to patients under the same antithrombotic therapy. METHODS Patients who underwent CF-LVAD between 2012 and 2018 were reviewed retrospectively from the institutionally adopted electronic database. Patients who underwent mitral valve replacement (MVR) surgery receiving the same anticoagulant and antiaggregant therapy were included as a control group. Demographics, epistaxis episodes, and nonepistaxis bleeding between the two groups were compared. RESULTS A total of 179 patients met the inclusion criteria (61 patients CF-LVAD group, 118 patients MVR group). The median (range) follow-up periods for the study (CF-LVAD) and control (MVR) groups were 370 (2819) and 545.70 (2356) days, respectively. There was a significant difference for frequency of bleeding episodes per month between CF-LVAD and MVR groups (p = 0.003 < 0.05). The most common site of bleeding was the anterior septum in both groups (90.9% for the CF-MVR group and 100% for the MVR group). While 14 patients (23%) had nonepistaxis bleeding in the CF-LVAD group, only two patients (1.7%) had nonepistaxis bleeding in the MVR group. There were significant differences in nonepistaxis bleeding rates between the CF-LVAD and MVR groups (χ2=19.79, p < 0.001). CONCLUSION Both epistaxis and nonepistaxis bleeding rates were higher in the CF-LVAD group than in the MVR group. This suggests that the use of CF-LVAD support could directly increase the risk of hemorrhagic complications. LEVEL OF EVIDENCE 2A (Etiology/Harm).
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Affiliation(s)
- Alper Koycu
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Baskent University, Ankara, 06490, Turkey
| | - Omer Vural
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Baskent University, Ankara, 06490, Turkey.
| | - Melike Bahcecitapar
- Department of Statistics, Faculty of Science, Hacettepe University, Ankara, 06800, Turkey
| | - Sabuhi Jafarov
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Baskent University, Ankara, 06490, Turkey
| | - Gulfem Beyazpinar
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, Baskent University, Ankara, 06490, Turkey
| | - Deniz Sarp Beyazpinar
- Department of Cardiovascular Surgery, Faculty of Medicine, Baskent University, Ankara, 06490, Turkey
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16
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Benchtop von Willebrand Factor Testing: Comparison of Commercially Available Ventricular Assist Devices and Evaluation of Variables for a Standardized Test Method. ASAIO J 2020; 65:481-488. [PMID: 30004942 DOI: 10.1097/mat.0000000000000849] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Gastrointestinal bleeding occurs in 20-30% of patients receiving ventricular assist devices (VADs) due, in part, to acquired von Willebrand syndrome. We examined factors to optimize a benchtop method to quantify changes in von Willebrand Factor (VWF) multimer distribution and function in VADs, then applied them to evaluate commercially available devices. Human plasma was circulated through flow loops with VADs. Several experimental conditions were examined, including temperature, viscosity, and enzyme inhibition. Samples were analyzed for VWF collagen-binding activity (VWF:CB) and VWF antigen level. von Willebrand Factor multimer profiles were quantified using gel electrophoresis, near-infrared in-gel visualization, and densitometric analysis. The VWF:CB/antigen ratio in the HeartMate II, CentriMag, and HVAD exhibited average decreases of 46%, 44%, and 36% from baseline after 360 minutes of operation. High molecular weight (hVWF) multimer loss occurred within 30 minutes, although the Levacor and control loop profiles were unchanged. Varying temperature and viscosity altered hVWF degradation rate, but not the final results. Inhibition of a disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13 (ADAMTS13) can potentially distinguish mechanoenzymatic cleavage of VWF from mechanical degradation. We developed a repeatable benchtop method to evaluate VWF compatibility of VADs similar to hemolysis testing that can be adopted for preclinical VAD evaluation.
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17
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Hilal T, Mudd J, DeLoughery TG. Hemostatic complications associated with ventricular assist devices. Res Pract Thromb Haemost 2019; 3:589-598. [PMID: 31624778 PMCID: PMC6781923 DOI: 10.1002/rth2.12226] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/08/2019] [Indexed: 01/03/2023] Open
Abstract
Hemostatic complications are common in patients with ventricular assist devices. The pathophysiologic mechanisms that lead to dysregulated hemostasis involve complex interactions between device surface, sheer stress, and blood flow. These factors lead to various manifestations that require a thorough understanding of the interplay among platelets, coagulation factors, and red cells. In this article, we review the pathophysiology of hematologic complications (bleeding, acquired von Willebrand disease, heparin-induced thrombocytopenia, hemolysis, stroke and pump thrombosis), the clinical manifestations, and the management of each. We summarize the evidence available for management of these entities and provide a pragmatic clinical review.
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Affiliation(s)
- Talal Hilal
- Division of Hematology/OncologyMayo Clinic Cancer CenterMayo ClinicPhoenixArizona
| | - James Mudd
- Center for Advanced Heart Disease and TransplantationProvidence Sacred Heart Medical CenterSpokaneWashington
| | - Thomas G. DeLoughery
- Division of Hematology/Medical OncologyKnight Cancer CenterOregon Health & Science UniversityPortlandOregon
- Division of Laboratory MedicineDepartment of PathologyOregon Health & Science UniversityPortlandOregon
- Division of Hematology/OncologyDepartment of PediatricsOregon Health & Science UniversityPortlandOregon
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18
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Non-physiological shear stress-induced blood damage in ventricular assist device. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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19
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Bartoli CR, Zhang DM, Hennessy-Strahs S, Kang J, Restle DJ, Bermudez C, Atluri P, Acker MA. Clinical and In Vitro Evidence That Left Ventricular Assist Device-Induced von Willebrand Factor Degradation Alters Angiogenesis. Circ Heart Fail 2019; 11:e004638. [PMID: 30354363 DOI: 10.1161/circheartfailure.117.004638] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background Gastrointestinal bleeding from angiodysplasia is a major problem in continuous-flow left ventricular assist device (LVAD) patients. LVAD shear stress causes pathologic degradation of VWF (von Willebrand factor). A mechanistic relationship between VWF degradation and angiodysplasia has not been explored. We tested 2 novel hypotheses: (1) clinical hypothesis: VWF fragments are elevated in LVAD patients that develop angiodysplasia and (2) in vitro hypothesis: VWF fragments generated during LVAD support alter angiogenesis, which may contribute to angiodysplasia. Methods and Results Clinical study: Paired blood samples were collected from continuous-flow LVAD patients (n=35). VWF was quantified with immunoblotting. In vitro experiments: (1) To investigate whether LVAD support alters angiogenesis, human endothelial cells were cultured with LVAD patient plasma (n=11). To investigate mechanism, endothelial cells were cultured with VWF fragments produced by exposing human VWF and ADAMTS-13 (VWF protease) to LVAD-like shear stress (175 dyne/cm2, n=8). Clinical study results: in all patients (n=35, mean support 666±430 days), LVAD support degraded high-molecular-weight VWF multimers ( P<0.0001) into low-molecular-weight VWF multimers ( P<0.0001) and VWF fragments ( P<0.0001). In patients with gastrointestinal bleeding from angiodysplasia (n=7), VWF fragments were elevated ( P=0.02) versus nonbleeders. In contrast, in patients with gastrointestinal bleeding without angiodysplasia, VWF fragments were not elevated versus nonbleeders ( P=0.96). In vitro experiments results: LVAD patient plasma caused abnormal angiogenesis with reduced tubule length ( P=0.04) and migration ( P=0.05). Similarly, endothelial cells grown with VWF degradation fragments exhibited reduced tubule length ( P<0.001) and migration ( P=0.01). Conclusions LVAD patients who bled from angiodysplasia had higher levels of VWF fragments than nonbleeders and gastrointestinal bleeders without angiodysplasia. VWF fragments caused abnormal angiogenesis in vitro. These findings suggest that VWF fragments may be a mechanistic link between LVAD support, abnormal angiogenesis, angiodysplasia, and gastrointestinal bleeding.
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Affiliation(s)
- Carlo R Bartoli
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (C.R.B., S.H.-S., C.B., P.A., M.A.A.)
| | - David M Zhang
- Washington University, School of Medicine, St Louis, MO (D.M.Z.)
| | - Samson Hennessy-Strahs
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (C.R.B., S.H.-S., C.B., P.A., M.A.A.)
| | - Jooeun Kang
- Vanderbilt University School of Medicine, Nashville, TN (J.K.)
| | | | - Christian Bermudez
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (C.R.B., S.H.-S., C.B., P.A., M.A.A.)
| | - Pavan Atluri
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (C.R.B., S.H.-S., C.B., P.A., M.A.A.)
| | - Michael A Acker
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (C.R.B., S.H.-S., C.B., P.A., M.A.A.)
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20
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A Novel Toroidal-Flow Left Ventricular Assist Device Minimizes Blood Trauma: Implications of Improved Ventricular Assist Device Hemocompatibility. Ann Thorac Surg 2018; 107:1761-1767. [PMID: 30586577 DOI: 10.1016/j.athoracsur.2018.11.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 10/17/2018] [Accepted: 11/26/2018] [Indexed: 01/14/2023]
Abstract
BACKGROUND Continuous-flow left ventricular assist devices (LVADs) cause blood trauma that includes von Willebrand factor degradation, platelet activation, and subclinical hemolysis. Blood trauma contributes to bleeding, thrombosis, and stroke, which cause significant morbidity and mortality. The TORVAD (Windmill Cardiovascular Systems, Inc, Austin, TX) is a first-of-its kind, toroidal-flow LVAD designed to minimize blood trauma. We tested the hypothesis that the TORVAD causes less blood trauma than the HeartMate II (Abbott Laboratories, Pleasanton, CA) LVAD. METHODS Whole human blood was circulated for 6 hours in ex vivo circulatory loops with a HeartMate II (n = 8; 10,000 rpm, 70 ± 6 mm Hg, 4.0 ± 0.1 L/min) or TORVAD (n = 6; 144 rpm, 72 ± 0.0 mm Hg, 4.3 ± 0.0 L/min). von Willebrand factor degradation was quantified with electrophoresis and immunoblotting. Platelet activation was quantified by cluster of differentiation (CD) 41/61 enzyme-linked immunosorbent assay (ELISA). Hemolysis was quantified by plasma free hemoglobin ELISA. RESULTS The TORVAD caused significantly less degradation of high-molecular-weight von Willebrand factor multimers (-10% ± 1% vs -21% ± 1%, p < 0.0001), accumulation of low-molecular-weight von Willebrand factor multimers (22% ± 2% vs 45% ± 2%, p < 0.0001), and accumulation of von Willebrand factor degradation fragments (7% ± 1% vs 25% ± 6%, p < 0.05) than the HeartMate II. The TORVAD did not activate platelets, whereas the HeartMate II caused significant platelet activation (CD 41/61: 645 ± 20 ng/mL vs 1,581 ± 150 ng/mL, p < 0.001; normal human CD 41/61, 593 ng/mL; range, 400 to 800 ng/mL). Similarly, the TORVAD caused minimal hemolysis, whereas the HeartMate II caused significant hemolysis (plasma free hemoglobin: 11 ± 2 vs 109 ± 10 mg/dL, p < 0.0001; normal human plasma free hemoglobin <4 mg/dL). CONCLUSIONS The TORVAD design, with markedly lower shear stress and pulsatile flow, caused significantly less blood trauma than the HeartMate II. LVADs with reduced blood trauma are likely to improve clinical outcomes and expand LVAD therapy into patients with less advanced heart failure.
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21
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Rosenberg G, Siedlecki CA, Jhun CS, Weiss WJ, Manning K, Deutsch S, Pierce W. Acquired Von Willebrand Syndrome and Blood Pump Design. Artif Organs 2018; 42:1119-1124. [DOI: 10.1111/aor.13291] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/05/2018] [Accepted: 04/30/2018] [Indexed: 12/27/2022]
Affiliation(s)
- Gerson Rosenberg
- Department of Surgery; The Pennsylvania State University; College of Medicine; Hershey
| | | | - Choon-Sik Jhun
- Department of Surgery; The Pennsylvania State University; College of Medicine; Hershey
| | - William J. Weiss
- Department of Surgery; The Pennsylvania State University; College of Medicine; Hershey
| | - Keefe Manning
- Biomedical Engineering; The Pennsylvania State University; University Park
| | - Steven Deutsch
- Applied Research Laboratory; The Pennsylvania State University; University Park PA, USA
| | - William Pierce
- Department of Surgery; The Pennsylvania State University; College of Medicine; Hershey
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22
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In pursuit of the optimal hemocompatible left ventricular assist device. J Thorac Cardiovasc Surg 2018; 157:600-601. [PMID: 30266391 DOI: 10.1016/j.jtcvs.2018.08.024] [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: 08/07/2018] [Accepted: 08/10/2018] [Indexed: 11/23/2022]
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23
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Morici N, Varrenti M, Brunelli D, Perna E, Cipriani M, Ammirati E, Frigerio M, Cattaneo M, Oliva F. Antithrombotic therapy in ventricular assist device (VAD) management: From ancient beliefs to updated evidence. A narrative review. IJC HEART & VASCULATURE 2018; 20:20-26. [PMID: 30229131 PMCID: PMC6141382 DOI: 10.1016/j.ijcha.2018.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/17/2018] [Accepted: 06/21/2018] [Indexed: 12/23/2022]
Abstract
Platelets play a key role in the pathogenesis of ventricular assist device (VAD) thrombosis; therefore, antiplatelet drugs are essential, both in the acute phase and in the long-term follow-up in VAD management. Aspirin is the most used agent and still remains the first-choice drug for lifelong administration after VAD implantation. Anticoagulant drugs are usually recommended, but with a wide range of efficacy targets. Dual antiplatelet therapy, targeting more than one pathway of platelet activation, has been used for patients developing a thrombotic event, despite an increased risk of bleeding complications. Although different strategies have been attempted, bleeding and thrombotic events remain frequent and there are no uniform strategies adopted for pharmacological management in the short and mid- or long-term follow up. The aim of this article is to provide an overview of the evidence from randomized clinical trials and observational studies with a focus on the pathophysiologic mechanisms underlying bleeding and thrombosis in VAD patients and the best antithrombotic regimens available.
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Affiliation(s)
- Nuccia Morici
- Intensive Cardiac Care Unit and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy.,Dept. of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Marisa Varrenti
- Health Science Department, Milano-Bicocca University, Milano, Italy
| | - Dario Brunelli
- Intensive Cardiac Care Unit and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy.,Transplant Center and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Enrico Perna
- Transplant Center and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Manlio Cipriani
- Transplant Center and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Enrico Ammirati
- Transplant Center and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Maria Frigerio
- Transplant Center and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
| | - Marco Cattaneo
- Health Science Department, Università Degli Studi di Milano, Milan, Italy.,Unità di Medicina 3, ASST Santi Paolo e Carlo, Milan, Italy
| | - Fabrizio Oliva
- Intensive Cardiac Care Unit and De Gasperis Cardio Center, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy
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24
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Oezpeker C, Zittermann A, Baurichter D, Morshuis M, Prohaska W, Kassner A, Erkilet G, Gummert J, Milting H. Changes in Von Willebrand factor profile predicts clinical outcomes in patients on mechanical circulatory support. J Card Surg 2018; 33:693-702. [PMID: 30199919 DOI: 10.1111/jocs.13794] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND The associations between mechanical circulatory support (MCS), acquired von Willebrand syndrome (AvWS), and clinical outcome are incompletely understood. METHODS In 128 heart failure patients with pulsatile MCS implants (65 total artificial heart or biventricular assist device implants, 63 left ventricular assist device [LVAD] implants) and 76 patients with continuous flow LVAD implants, we analyzed the von Willebrand factor (vWF) profile before (≤24 h) and 17.5 (standard deviation: 5.1) days after device implant. We determined vWF concentrations, vWF activity, and vWF collagen binding capacity and calculated ratios of vWF activity/binding capacity with vWF concentration. The relation of the vWF profile with clinical outcomes such as stroke, gastrointestinal bleeding, and survival was also evaluated. Events were assessed up to 1 year of device implant. RESULTS All entities of vWF were already significantly elevated preoperatively and remained high after MCS implantation. The ratios of vWF activity/concentration (vWF:RCo/Ag) and collagen binding capacity/concentration (vWF:CBA/Ag) were significantly reduced preoperatively and remained low postoperatively, indicating AvWS. The preoperative alterations in the vWF profile were already present in patients without intra-aortic balloon pump and/or extracorporeal circulatory membrane oxygenation implants. The vWF profile was unrelated to postoperative stroke. However, a higher postoperative ratio of vWF:CBA/Ag was independently associated with increased gastrointestinal bleeding. In addition, a postoperative increase in vWF concentrations and activity were independent predictors of increased 1-year mortality. CONCLUSIONS Our data indicate that AvWS is present in heart failure patients before device implantation, and is independently associated with clinical outcomes, especially with 1-year mortality.
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Affiliation(s)
- Cenk Oezpeker
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Armin Zittermann
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Daniela Baurichter
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Michel Morshuis
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Wolfgang Prohaska
- Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Astrid Kassner
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Gülsüm Erkilet
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Jan Gummert
- Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center, NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Hendrik Milting
- Erich and Hanna Klessmann-Institute for Cardiovascular Research and Development, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
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25
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Bleeding and thrombosis associated with ventricular assist device therapy. J Heart Lung Transplant 2017; 36:1164-1173. [DOI: 10.1016/j.healun.2017.05.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/03/2017] [Accepted: 05/09/2017] [Indexed: 01/03/2023] Open
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Heilmann C, Trummer G, Beyersdorf F, Brehm K, Berchtold-Herz M, Schelling J, Geisen U, Zieger B. Acquired Von Willebrand syndrome in patients on long-term support with HeartMate II. Eur J Cardiothorac Surg 2017; 51:587-590. [PMID: 28082469 DOI: 10.1093/ejcts/ezw348] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/19/2016] [Indexed: 01/15/2023] Open
Abstract
Objectives Impaired binding of Von Willebrand factor (VWF) to platelets and to collagen due to acquired Von Willebrand syndrome (AVWS) is associated with support from a ventricular assist device (VAD) and can contribute to bleeding tendencies in patients with VADs. The onset of AVWS has been shown to occur immediately after VAD implantation. Our aim was to determine long-term data on AVWS in VAD patients. Methods We analysed 278 data sets of 74 patients on HeartMate II (HMII) support for 3-80 months after implantation (11.2 ± 12.1, median 6.3 months.). Ristocetin cofactor activity (VWF:RCo), collagen binding capacity (VWF:CB), VWF antigen (VWF:Ag) and the ratios of VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag were determined. Further, the presence of high molecular weight (HMW) multimers of VWF was investigated. Results Abnormally low values of VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag were found in 69% and 97% of blood samples, respectively. Only ten of 181 multimer analyses showed a normal pattern, and HMW multimers were present in both specimens in only one of the 74 patients. No significant changes in these parameters were observed over time. The VWF:CB/VWF:Ag ratio correlated with the multimer patterns, whereas the VWF:RCo/VWF:Ag ratio seemed to be less sensitive for AVWS. Conclusions Our data indicate that AVWS is a typical phenomenon in patients with VAD support and that there are no time-dependent changes in these parameters apparent in most patients on long-term support with HMII.
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Affiliation(s)
- Claudia Heilmann
- Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Georg Trummer
- Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Friedhelm Beyersdorf
- Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Kerstin Brehm
- Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Michael Berchtold-Herz
- Department of Cardiovascular Surgery, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
| | - Johannes Schelling
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ulrich Geisen
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center Freiburg, Freiburg, Germany
| | - Barbara Zieger
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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27
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Kang J, Hennessy-Strahs S, Kwiatkowski P, Bermudez CA, Acker MA, Atluri P, McConnell PI, Bartoli CR. Continuous-Flow LVAD Support Causes a Distinct Form of Intestinal Angiodysplasia. Circ Res 2017; 121:963-969. [DOI: 10.1161/circresaha.117.310848] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 07/17/2017] [Accepted: 07/20/2017] [Indexed: 12/15/2022]
Abstract
Rationale:
The objective of this autopsy study was to determine whether gastrointestinal angiodysplasia develops during continuous-flow left ventricular assist device (LVAD) support.
Objective:
LVAD support causes pathologic degradation of von Willebrand factor (vWF) and bleeding from gastrointestinal angiodysplasia at an alarming rate. It has been speculated that LVAD support itself may cause angiodysplasia. The relationship to abnormal vWF metabolism is unknown. We tested the hypothesis that abnormal gastrointestinal vascularity develops during continuous-flow LVAD support.
Methods and Results:
Small bowel was obtained from deceased humans, cows, and sheep supported with a continuous-flow LVAD (n=9 LVAD, n=11 control). Transmural sections of jejunum were stained with fluorescein isothiocyanate–conjugated isolectin-B4 for endothelium to demarcate vascular structures and quantify intestinal vascularity. Paired plasma samples were obtained from humans before LVAD implantation and during LVAD support (n=41). vWF multimers and degradation fragments were quantified with agarose and polyacrylamide gel electrophoresis and immunoblotting. Abnormal vascular architecture was observed in the submucosa of the jejunum of human patients, cows, and sheep supported with a continuous-flow LVAD. Intestinal vascularity was significantly higher after LVAD support versus controls (5.2±1.0% versus 2.1±0.4%,
P
=0.004). LVAD support caused significant degradation of high–molecular-weight vWF multimers (–9±1%,
P
<0.0001) and accumulation of low–molecular-weight vWF multimers (+40±5%,
P
<0.0001) and vWF degradation fragments (+53±6%,
P
<0.0001).
Conclusions:
Abnormal intestinal vascular architecture and LVAD-associated vWF degradation were consistent findings in multiple species supported with a continuous-flow LVAD. These are the first direct evidence that LVAD support causes gastrointestinal angiodysplasia. Pathologic vWF metabolism may be a mechanistic link between LVAD support, abnormal angiogenesis, gastrointestinal angiodysplasia, and bleeding.
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Affiliation(s)
- Jooeun Kang
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Samson Hennessy-Strahs
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Pawel Kwiatkowski
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Christian A. Bermudez
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Michael A. Acker
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Pavan Atluri
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Patrick I. McConnell
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
| | - Carlo R. Bartoli
- From the MD/PhD Program, Vanderbilt University School of Medicine, Nashville, TN (J.K.); Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia (J.K., S.H.-S., C.A.B., M.A.A., P.A., C.R.B.); and The Ohio State University, Columbus (P.K., P.I.M.)
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Clinical and In Vitro Evidence That Subclinical Hemolysis Contributes to LVAD Thrombosis. Ann Thorac Surg 2017; 105:807-814. [PMID: 28942075 DOI: 10.1016/j.athoracsur.2017.05.060] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/06/2017] [Accepted: 05/15/2017] [Indexed: 12/23/2022]
Abstract
BACKGROUND Recent data suggest that hemolysis contributes to left ventricular assist device (LVAD) thrombosis, but the mechanism is unknown. In a clinical study, we measured plasma free hemoglobin (pfHgb) and the incidence of LVAD thrombosis. In an in vitro study, we examined biophysical relationships between shear stress, pfHgb and von Willebrand factor (vWF) metabolism toward understanding mechanisms of LVAD thrombosis. METHODS In the clinical study, blood samples were obtained from continuous-flow LVAD patients (n = 30). Plasma free hemoglobin was measured via enzyme-linked immunosorbent assay. Plasma lactate dehydrogenase (LDH) was measured with a fluorimetric assay. In the in vitro study, to investigate mechanism, human plasma (n = 10) was exposed to LVAD-like shear stress (175 dyne/cm2) with and without free hemoglobin (30 mg/dL). ADAMTS-13 (the vWF protease) activity was quantified with Förster resonance energy transfer. vWF size was quantified with immunoblotting. vWF clotting function was quantified with an enzyme-linked immunosorbent assay. RESULTS In the clinical study, LVAD support caused subclinical hemolysis. In all patients, LDH increased significantly from 213 ± 9 U/L to 366 ± 31 U/L at 10 days of support (p < 0.0001) and remained significantly elevated at 280 ± 18 U/L at 1 month of support (p < 0.01). In 21 patients that did not develop LVAD thrombosis, pfHgb increased early but decreased over time (pre-LVAD: 5.2 ± 0.8 mg/dL; 1 week: 19.8 ± 4.4 mg/dL, p < 0.01; 3 months: 9.3 ± 2.2 mg/dL, p = 0.07). In 9 patients that developed LVAD thrombosis, pfHgb was significantly elevated versus patients without thrombosis before (p < 0.001) and after 3 months (p < 0.05) of support (pre-LVAD: 20.2 ± 6.3 mg/dL; 1 week: 17.3 ± 3.7 mg/dL; 3 months: 21.5 ± 7.8 mg/dL). Similarly, after 3 months, patients that did not develop LVAD thrombosis had an LDH of 271 ± 28 U/L, whereas patients that later developed LVAD thrombosis had a significantly higher LDH of 625 ± 210 U/L (p = 0.02). In the in vitro study, shear stress degraded vWF similarly to an LVAD. Free hemoglobin inhibited ADAMTS-13 activity during shear stress (633 ± 27 ng/mL to 565 ± 24 ng/mL; p < 0.001). vWF was thereby protected from degradation, 4 vWF fragments decreased significantly (p ≤ 0.05), and vWF clotting function increased (1.15 ± 0.09 U/mL to 1.29 ± 0.09 U/mL, p = 0.06). CONCLUSIONS These are the first data to demonstrate mechanistic relationships between subclinical hemolysis and a procoagulant state during continuous-flow LVAD support. Patients with high pfHgb and LDH were more likely to develop LVAD thrombosis. In vitro experiments demonstrated that free hemoglobin inhibited ADAMTS-13, protected vWF from degradation, increased vWF clotting function, and created a procoagulant state. As such, pfHgb may be a clinical target to prevent LVAD thrombosis.
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29
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Jennes E, Guggenberger D, Zotz R, Thompson L, Brümmendorf TH, Koschmieder S, Jost E. Perioperative intravenous immunoglobulin treatment in a patient with severe acquired von Willebrand syndrome: case report and review of the literature. Clin Case Rep 2017; 5:664-670. [PMID: 28469872 PMCID: PMC5412814 DOI: 10.1002/ccr3.890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 12/23/2016] [Accepted: 01/04/2017] [Indexed: 02/02/2023] Open
Abstract
Acquired von Willebrand syndrome may be related to plasma cell dyscrasia and can cause severe bleeding complications. Treatment, for example, with intravenous immunoglobulins may be indicated in selected cases. Physicians treating plasma cell dyscrasia have to be aware of bleeding complications in these patients, and clarification is necessary.
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Affiliation(s)
- Eva Jennes
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation Medical Faculty RWTH Aachen University Aachen Germany
| | | | - Rainer Zotz
- Institute for Laboratory Medicine, Blood Coagulation and Transfusion Medicine (LBT) Düsseldorf Germany
| | - Lora Thompson
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation Medical Faculty RWTH Aachen University Aachen Germany
| | - Tim H Brümmendorf
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation Medical Faculty RWTH Aachen University Aachen Germany
| | - Steffen Koschmieder
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation Medical Faculty RWTH Aachen University Aachen Germany
| | - Edgar Jost
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation Medical Faculty RWTH Aachen University Aachen Germany
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30
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Bartoli CR, Kang J, Zhang D, Howard J, Acker M, Atluri P, Motomura T. Left Ventricular Assist Device Design Reduces von Willebrand Factor Degradation: A Comparative Study Between the HeartMate II and the EVAHEART Left Ventricular Assist System. Ann Thorac Surg 2017; 103:1239-1244. [DOI: 10.1016/j.athoracsur.2016.06.112] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 06/01/2016] [Accepted: 06/22/2016] [Indexed: 11/25/2022]
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31
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Capoccia M. Mechanical Circulatory Support for Advanced Heart Failure: Are We about to Witness a New "Gold Standard"? J Cardiovasc Dev Dis 2016; 3:E35. [PMID: 29367578 PMCID: PMC5715724 DOI: 10.3390/jcdd3040035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 12/03/2016] [Accepted: 12/06/2016] [Indexed: 01/08/2023] Open
Abstract
The impact of left ventricular assist devices (LVADs) for the treatment of advanced heart failure has played a significant role as a bridge to transplant and more recently as a long-term solution for non-eligible candidates. Continuous flow left ventricular assist devices (CF-LVADs), based on axial and centrifugal design, are currently the most popular devices in view of their smaller size, increased reliability and higher durability compared to pulsatile flow left ventricular assist devices (PF-LVADs). The trend towards their use is increasing. Therefore, it has become mandatory to understand the physics and the mathematics behind their mode of operation for appropriate device selection and simulation set up. For this purpose, this review covers some of these aspects. Although very successful and technologically advanced, they have been associated with complications such as pump thrombosis, haemolysis, aortic regurgitation, gastro-intestinal bleeding and arterio-venous malformations. There is perception that the reduced arterial pulsatility may be responsible for these complications. A flow modulation control approach is currently being investigated in order to generate pulsatility in rotary blood pumps. Thrombus formation remains the most feared complication that can affect clinical outcome. The development of a preoperative strategy aimed at the reduction of complications and patient-device suitability may be appropriate. Patient-specific modelling based on 3D reconstruction from CT-scan combined with computational fluid dynamic studies is an attractive solution in order to identify potential areas of stagnation or challenging anatomy that could be addressed to achieve the desired outcome. The HeartMate II (axial) and the HeartWare HVAD (centrifugal) rotary blood pumps have been now used worldwide with proven outcome. The HeartMate III (centrifugal) is now emerging as the new promising device with encouraging preliminary results. There are now enough pumps on the market: it is time to focus on the complications in order to achieve the full potential and selling-point of this type of technology for the treatment of the increasing heart failure patient population.
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Affiliation(s)
- Massimo Capoccia
- Scottish National Advanced Heart Failure Service, Golden Jubilee National Hospital, Glasgow G81 4DY, UK.
- Biomedical Engineering, University of Strathclyde, Glasgow G4 0NW, UK.
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32
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Kang J, Zhang DM, Restle DJ, Kallel F, Acker MA, Atluri P, Bartoli CR. Reduced continuous-flow left ventricular assist device speed does not decrease von Willebrand factor degradation. J Thorac Cardiovasc Surg 2016; 151:1747-1754.e1. [DOI: 10.1016/j.jtcvs.2016.01.031] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 01/09/2016] [Accepted: 01/15/2016] [Indexed: 02/07/2023]
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33
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Naito N, Mizuno T, Nishimura T, Kishimoto S, Takewa Y, Eura Y, Kokame K, Miyata T, Date K, Umeki A, Ando M, Ono M, Tatsumi E. Influence of a Rotational Speed Modulation System Used With an Implantable Continuous-Flow Left Ventricular Assist Device on von Willebrand Factor Dynamics. Artif Organs 2016; 40:877-83. [DOI: 10.1111/aor.12666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Noritsugu Naito
- Department of Artificial Organs; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Toshihide Mizuno
- Department of Artificial Organs; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Takashi Nishimura
- Department of Cardiac Surgery; Tokyo Metropolitan Geriatric Hospital; Tokyo Japan
| | - Satoru Kishimoto
- Department of Artificial Organs; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Yoshiaki Takewa
- Department of Artificial Organs; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Yuka Eura
- Department of Molecular Pathogenesis; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Koichi Kokame
- Department of Molecular Pathogenesis; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Toshiyuki Miyata
- Department of Molecular Pathogenesis; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
| | - Kazuma Date
- Department of Cardiothoracic Surgery; The University of Tokyo; Tokyo Japan
| | - Akihide Umeki
- Department of Cardiothoracic Surgery; The University of Tokyo; Tokyo Japan
| | - Masahiko Ando
- Department of Cardiothoracic Surgery; The University of Tokyo; Tokyo Japan
| | - Minoru Ono
- Department of Cardiothoracic Surgery; The University of Tokyo; Tokyo Japan
| | - Eisuke Tatsumi
- Department of Artificial Organs; National Cerebral and Cardiovascular Center, Research Institute; Osaka Japan
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34
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Schumer EM, Black MC, Monreal G, Slaughter MS. Left ventricular assist devices: current controversies and future directions. Eur Heart J 2015; 37:3434-3439. [PMID: 26543045 DOI: 10.1093/eurheartj/ehv590] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 08/04/2015] [Accepted: 10/12/2015] [Indexed: 11/12/2022] Open
Abstract
Advanced heart failure is a growing epidemic that leads to significant suffering and economic losses. The development of left ventricular assist devices (LVADs) has led to improved quality of life and long-term survival for patients diagnosed with this devastating condition. This review briefly summarizes the short history and clinical outcomes of LVADs and focuses on the current controversies and issues facing LVAD therapy. Finally, the future directions for the role of LVADs in the treatment of end-stage heart failure are discussed.
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Affiliation(s)
- Erin M Schumer
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, 201 Abraham Flexner Way, Suite 1200, Louisville, KY 40202, USA
| | - Matthew C Black
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, 201 Abraham Flexner Way, Suite 1200, Louisville, KY 40202, USA
| | - Gretel Monreal
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, 201 Abraham Flexner Way, Suite 1200, Louisville, KY 40202, USA
| | - Mark S Slaughter
- Department of Cardiovascular and Thoracic Surgery, University of Louisville, 201 Abraham Flexner Way, Suite 1200, Louisville, KY 40202, USA
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35
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Schumer EM, Ising MS, Slaughter MS. The current state of left ventricular assist devices: challenges facing further development. Expert Rev Cardiovasc Ther 2015; 13:1185-93. [DOI: 10.1586/14779072.2015.1098534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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36
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Inhibition of ADAMTS-13 by Doxycycline Reduces von Willebrand Factor Degradation During Supraphysiological Shear Stress. JACC-HEART FAILURE 2015; 3:860-9. [DOI: 10.1016/j.jchf.2015.06.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 06/08/2015] [Accepted: 06/12/2015] [Indexed: 11/19/2022]
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37
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Susen S, Rauch A, Van Belle E, Vincentelli A, Lenting PJ. Circulatory support devices: fundamental aspects and clinical management of bleeding and thrombosis. J Thromb Haemost 2015; 13:1757-67. [PMID: 26302994 DOI: 10.1111/jth.13120] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/02/2015] [Indexed: 12/01/2022]
Abstract
Circulatory support devices are increasingly being used to overcome cardiac or respiratory failure. Long-term devices are used either as a 'bridge to transplant' to support patients who are unable to wait any longer for a heart transplant, or, more recently, as 'destination therapy' for older patients suffering from end-stage heart failure and who have contraindications to heart transplantation. Short-term support devices for high-risk percutaneous coronary intervention, or as a 'bridge for decision' for patients suffering from refractory cardiogenic shock, have also been developed. The clinical benefit of such assist devices has been demonstrated in several important studies, but, unfortunately, thrombotic and bleeding complications are two major clinical issues in patients requiring these devices. Overcoming these issues is of major importance to allow the safe and broad use of these devices, and to consider them as true alternatives to heart transplantation. The present review focuses on thrombotic and bleeding complications, and describes how the risk of thrombosis and bleeding may vary according to the clinical indication, but also according to the type of device. We describe the current knowledge of the mechanisms underlying the occurrence of these complications, provide some guidance for choosing the most appropriate anticoagulation regimen to prevent their occurrence for each type of device and indication, and provide some recommendations for the management of patients when the complication occurs.
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Affiliation(s)
- S Susen
- Department of Hematology and Transfusion, Lille University Hospital, Lille, France
- Institut Pasteur de Lille, EGID, INSERM UMR 1011, University of Lille 2, Lille, France
| | - A Rauch
- Department of Hematology and Transfusion, Lille University Hospital, Lille, France
- Institut Pasteur de Lille, EGID, INSERM UMR 1011, University of Lille 2, Lille, France
| | - E Van Belle
- Institut Pasteur de Lille, EGID, INSERM UMR 1011, University of Lille 2, Lille, France
- Department of Cardiology, Lille University Hospital, Lille, France
| | - A Vincentelli
- Institut Pasteur de Lille, EGID, INSERM UMR 1011, University of Lille 2, Lille, France
- Department of Cardiology, Lille University Hospital, Lille, France
- Department of Cardiac Surgery, Lille University Hospital, Lille, France
| | - P J Lenting
- Inserm U1176 & UMR_S 1176, University Paris-Sud, Le Kremlin Bicêtre, France
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38
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Morimoto Y, Nakatani T, Yokoe C, Kudo C, Hanamoto H, Niwa H. Haemostatic management for oral surgery in patients supported with left ventricular assist device--a preliminary retrospective study. Br J Oral Maxillofac Surg 2015; 53:991-5. [PMID: 26362416 DOI: 10.1016/j.bjoms.2015.08.262] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/21/2015] [Indexed: 11/18/2022]
Abstract
We investigated haemostatic management, frequency of postoperative bleeding, and prognosis of patients who had left ventricular assist devices, and who were having oral surgical procedures between April 2002 and March 2014, to identify risk factors for bleeding and find out which were the best methods of haemostasis. Medical records were examined retrospectively and we recorded details of the patients, and frequency of bleeding together with factors associated with it. Twenty-nine patients had 39 oral operations, and there were 17 bleeds (44%). The first procedure for each patient was used for statistical calculations. Duration of bleeding tended to be longer for patients with implantable devices (median (interquartile range, IQR) 12.0 (3-18) days) than for those with extracorporeal devices (median (IQR) 3.0 (1-4) days; p=0.079). There was a significantly greater difference in prothrombin time-international normalised ratio (PT-INR) before and after operation in patients who bled, whose median (range) was 0.85 (0.2-1.81), than in those who did not (median (IQR) 0.16 (-0.09-0.31) (p=0.015). There were moderate correlations with postoperative bleeding were seen for the difference between preoperative and postoperative PT-INR (r=0.479, p=0.012) and PT-INR value when bleeding (r=0.407, p=0.035). In conclusion, postoperative bleeding occurred after oral operations in 17/29 patients with left ventricular assist devices by a median (IQR) of 0.85 (0.2-1.81) of the preoperative value.
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Affiliation(s)
- Yoshinari Morimoto
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University; Department of Dentistry, National Cerebral and Cardiovascular Center; Department of Dental Anesthesiology, Graduate School of Dentistry, Osaka University.
| | - Takeshi Nakatani
- Department of Organ Transplantation, National Cerebral and Cardiovascular Center
| | - Chizuko Yokoe
- Department of Anesthesiology, Graduate School of Dentistry, Kanagawa Dental University
| | - Chiho Kudo
- Department of Dentistry, National Cerebral and Cardiovascular Center; Department of Dental Anesthesiology, Graduate School of Dentistry, Osaka University
| | - Hiroshi Hanamoto
- Department of Dentistry, National Cerebral and Cardiovascular Center; Department of Dental Anesthesiology, Graduate School of Dentistry, Osaka University
| | - Hitoshi Niwa
- Department of Dental Anesthesiology, Graduate School of Dentistry, Osaka University
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Immediate recovery of acquired von Willebrand syndrome after left ventricular assist device explantation: implications for heart transplantation. ASAIO J 2015; 61:e1-4. [PMID: 25251586 DOI: 10.1097/mat.0000000000000157] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
All patients supported with continuous flow-left ventricular assist devices (CF-LVADs) develop acquired von Willebrand syndrome due to the loss of von Willebrand factor (vWF) high molecular weight (HMW) multimers and this phenomenon has been associated with clinical manifestation of bleeding diatheses. The precise timing of postoperative recovery of HMW multimers and correction of this condition after CF-LVAD explantation and heart transplantation is unknown. We sought to determine the specific timing of HMW multimer recovery by serially quantifying plasma vWF multimer ratios after CF-LVAD explant and orthotopic heart transplantation (OHT) in a patient implanted with a HeartWare ventricular assist device. Using densitometric analysis of multimer patterns, we demonstrated complete recovery of HMW multimers within the first few hours following CF-LVAD explant and OHT. These findings have critical implications in the context of perioperative bleeding diatheses in patients bridged to transplantation with a CF-LVAD.
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Restle DJ, Zhang DM, Hung G, Howard JL, Kallel F, Acker MA, Atluri P, Bartoli CR. Preclinical Models for Translational Investigations of Left Ventricular Assist Device-Associated von Willebrand Factor Degradation. Artif Organs 2015; 39:569-75. [PMID: 25810063 DOI: 10.1111/aor.12428] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Evidence suggests a major role for von Willebrand factor (vWF) in left ventricular assist device (LVAD)-associated bleeding. However, the mechanisms of vWF degradation during LVAD support are not well understood. We developed: (i) a simple and inexpensive vortexer model; and (ii) a translational LVAD mock circulatory loop to perform preclinical investigations of LVAD-associated vWF degradation. Whole blood was obtained from LVAD patients (n = 8) and normal humans (n = 15). Experimental groups included: (i) blood from continuous-flow LVAD patients (baseline vs. post-LVAD, n = 8); (ii) blood from normal humans (baseline vs. 4 h in vitro laboratory vortexer, ∼ 2400 rpm, shear stress ∼175 dyne/cm(2) , n = 8); and (iii) blood from normal humans (baseline vs. 12 h HeartMate II mock circulatory loop, 10 000 rpm, n = 7). vWF multimers and degradation fragments were characterized with electrophoresis and immunoblotting. Blood from LVAD patients, blood exposed to in vitro supraphysiologic shear stress, and blood circulated through an LVAD mock circulatory loop demonstrated a similar profile of decreased large vWF multimers and increased vWF degradation fragments. A laboratory vortexer and an LVAD mock circulatory loop reproduced the pathologic degradation of vWF that occurs during LVAD support. Both models are appropriate for preclinical studies of LVAD-associated vWF degradation.
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Affiliation(s)
- David J Restle
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - David M Zhang
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - George Hung
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Jessica L Howard
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | | | - Michael A Acker
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Pavan Atluri
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Carlo R Bartoli
- Division of Cardiovascular Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
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Bartoli CR, Restle DJ, Zhang DM, Acker MA, Atluri P. Pathologic von Willebrand factor degradation with a left ventricular assist device occurs via two distinct mechanisms: Mechanical demolition and enzymatic cleavage. J Thorac Cardiovasc Surg 2015; 149:281-9. [DOI: 10.1016/j.jtcvs.2014.09.031] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 08/21/2014] [Accepted: 09/04/2014] [Indexed: 02/04/2023]
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42
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Multicentre Canadian Experience With the HeartWare Ventricular Assist Device: Concerns About Adverse Neurological Outcomes. Can J Cardiol 2014; 30:1662-7. [DOI: 10.1016/j.cjca.2014.07.746] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/18/2014] [Accepted: 07/27/2014] [Indexed: 01/06/2023] Open
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Chan CHH, Pieper IL, Fleming S, Friedmann Y, Foster G, Hawkins K, Thornton CA, Kanamarlapudi V. The Effect of Shear Stress on the Size, Structure, and Function of Human von Willebrand Factor. Artif Organs 2014; 38:741-50. [DOI: 10.1111/aor.12382] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Chris Hoi Houng Chan
- Institute of Life Science; College of Medicine; Swansea University; Swansea Wales UK
| | - Ina Laura Pieper
- Institute of Life Science; College of Medicine; Swansea University; Swansea Wales UK
| | - Scott Fleming
- Institute of Life Science; College of Medicine; Swansea University; Swansea Wales UK
| | - Yasmin Friedmann
- Institute of Life Science; College of Medicine; Swansea University; Swansea Wales UK
| | - Graham Foster
- Institute of Life Science; Calon Cardio-Technology Ltd; Swansea Wales UK
| | - Karl Hawkins
- Institute of Life Science; College of Medicine; Swansea University; Swansea Wales UK
| | - Catherine A. Thornton
- Institute of Life Science; College of Medicine; Swansea University; Swansea Wales UK
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Insights into the mechanism(s) of von Willebrand factor degradation during mechanical circulatory support. J Thorac Cardiovasc Surg 2014; 147:1634-43. [DOI: 10.1016/j.jtcvs.2013.08.043] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/19/2013] [Accepted: 08/16/2013] [Indexed: 11/19/2022]
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Bartoli CR, Ailawadi G, Kern JA. Diagnosis, Nonsurgical Management, and Prevention of LVAD Thrombosis. J Card Surg 2013; 29:83-94. [DOI: 10.1111/jocs.12238] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Carlo R. Bartoli
- Division of Cardiovascular Surgery; University of Pennsylvania Medical Center; Philadelphia Pennsylvania
| | - Gorav Ailawadi
- Division of Thoracic and Cardiovascular Surgery; University of Virginia Health System; Charlottesville Virginia
| | - John A. Kern
- Division of Thoracic and Cardiovascular Surgery; University of Virginia Health System; Charlottesville Virginia
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