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Straccia A, Chassagne F, Barbour MC, Beckman J, Li S, Mahr C, Aliseda A. A Computational Investigation of the Effects of Temporal Synchronization of Left Ventricular Assist Device Speed Modulation with the Cardiac Cycle on Intraventricular Hemodynamics. Ann Biomed Eng 2024; 52:1763-1778. [PMID: 38517620 DOI: 10.1007/s10439-024-03489-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/07/2024] [Indexed: 03/24/2024]
Abstract
Patients with advanced heart failure are implanted with a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy. Despite advances in pump design, the risk of stroke remains high. LVAD implantation significantly alters intraventricular hemodynamics, where regions of stagnation or elevated shear stresses promote thrombus formation. Third generation pumps incorporate a pulsatility mode that modulates rotational speed of the pump to enhance in-pump washout. We investigated how the timing of the pulsatility mode with the cardiac cycle affects intraventricular hemodynamic factors linked to thrombus formation. Computational fluid dynamics simulations with Lagrangian particle tracking to model platelet behavior in a patient-specific left ventricle captured altered intraventricular hemodynamics due to LVAD implantation. HeartMate 3 incorporates a pulsatility mode that modulates the speed of the pump every two seconds. Four different timings of this pulsatility mode with respect to the cardiac cycle were investigated. A strong jet formed between the mitral valve and inflow cannula. Blood stagnated in the left ventricular outflow tract beneath a closed aortic valve, in the near-wall regions off-axis of the jet, and in a large counterrotating vortex near the anterior wall. Computational results showed good agreement with particle image velocimetry results. Synchronization of the pulsatility mode with peak systole decreased stasis, reflected in the intraventricular washout of virtual contrast and Lagrangian particles over time. Temporal synchronization of HeartMate 3 pulsatility with the cardiac cycle reduces intraventricular stasis and could be beneficial for decreasing thrombogenicity.
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Affiliation(s)
- Angela Straccia
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
| | | | - Michael C Barbour
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Jennifer Beckman
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Song Li
- Institute for Advanced Cardiac Care, Medical City Healthcare, Dallas, TX, USA
| | - Claudius Mahr
- Institute for Advanced Cardiac Care, Medical City Healthcare, Dallas, TX, USA
| | - Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
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2
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Hong Y, Shin S, Nasim U, Roberts KG, Potchernikov AS, Liu KY, Dufendach KA, Skoog DJ, Bacchetta M, Cook KE. Hemocompatibility Evaluation of a Novel Ambulatory Pulmonary Assist System Using a Lightweight Axial-Flow Pump. ASAIO J 2024:00002480-990000000-00481. [PMID: 38728744 DOI: 10.1097/mat.0000000000002227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024] Open
Abstract
The Pulmonary Assist System (PAS) is currently under development as a wearable respiratory assist system. In this study, the hemocompatibility of the PAS's axial-flow mechanical pump (AFP) was compared to other contemporary mechanical pumps in an acute ovine model. The PAS was attached to a normal sheep in a venovenous configuration using one of three pumps: 1) AFP, 2) ReliantHeart HeartAssist 5 (control), or 3) Abbott Pedimag (control) (n = 5 each). Each sheep was supported on the PAS for 12 hours with two L/minute of blood flow and four L/minute of sweep gas. Hemolysis, coagulation, inflammation, and platelet activation and loss were compared among the groups. In this study, the plasma-free hemoglobin (pfHb) was less than 10 mg/dl in all groups. The pfHb was significantly lower in the AFP group compared to other groups. There was no significant clot formation in the pumps and oxygenators in all groups. Furthermore, no significant differences in coagulation (oxygenator resistance, fibrinopeptide A), inflammation (white blood cell counts, IL-8), and platelet activation and loss (p-selectin, platelet counts) were observed among the groups (all, p > 0.05). This study demonstrates equivalent hemocompatibility of the PAS's AFP to other contemporary mechanical pumps with a reduced level of hemolysis on startup.
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Affiliation(s)
- Yeahwa Hong
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Surgery
| | - Suji Shin
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Umar Nasim
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Kalliope G Roberts
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Alexander S Potchernikov
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Kimberly Y Liu
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Keith A Dufendach
- Cardiothoracic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - David J Skoog
- Advanced Respiratory Technologies, Inc, Pittsburgh, Pennsylvania
| | - Matthew Bacchetta
- Cardiac Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Keith E Cook
- From the Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
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3
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Keshav Chivukula V, Beckman J, Li S, Akoum N, Aliseda A, Mahr C. Atrial fibrillation increases thrombogenicity of LVAD therapy. Int J Artif Organs 2024; 47:329-337. [PMID: 38742880 DOI: 10.1177/03913988241251706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
BACKGROUND This study investigates the hypothesis that presence of atrial fibrillation (AF) in LVAD patients increases thrombogenicity in the left ventricle (LV) and exacerbates stroke risk. METHODS Using an anatomical LV model implanted with an LVAD inflow cannula, we analyze thrombogenic risk and blood flow patterns in either AF or sinus rhythm (SR) using unsteady computational fluid dynamics (CFD). To analyze platelet activation and thrombogenesis in the LV, hundreds of thousands of platelets are individually tracked to quantify platelet residence time (RT) and shear stress accumulation history (SH). RESULTS The irregular and chaotic mitral inflow associated with AF results in markedly different intraventricular flow patterns, with profoundly negative impact on blood flow-induced stimuli experienced by platelets as they traverse the LV. Twice as many platelets accumulated very high SH in the LVAD + AF case, resulting in a 36% increase in thrombogenic potential score, relative to the LVAD + SR case. CONCLUSIONS This supports the hypothesis that AF results in unfavorable blood flow patterns in the LV adding to an increased stroke risk for LVAD + AF patients. Quantification of thrombogenic risk associated with AF for LVAD patients may help guide clinical decision-making on interventions to mitigate the increased risk of thromboembolic events.
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Affiliation(s)
- Venkat Keshav Chivukula
- Department of Biomedical Engineering and Science, Florida Institute of Technology, Melbourne, FL, USA
| | - Jennifer Beckman
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Song Li
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Nazem Akoum
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, WA, USA
| | - Claudius Mahr
- Division of Cardiology, University of Washington, Seattle, WA, USA
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4
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Klenk C, Erber J, Fresacher D, Röhrl S, Lengl M, Heim D, Irl H, Schlegel M, Haller B, Lahmer T, Diepold K, Rasch S, Hayden O. Platelet aggregates detected using quantitative phase imaging associate with COVID-19 severity. COMMUNICATIONS MEDICINE 2023; 3:161. [PMID: 37935793 PMCID: PMC10630365 DOI: 10.1038/s43856-023-00395-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 10/25/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND The clinical spectrum of acute SARS-CoV-2 infection ranges from an asymptomatic to life-threatening disease. Considering the broad spectrum of severity, reliable biomarkers are required for early risk stratification and prediction of clinical outcomes. Despite numerous efforts, no COVID-19-specific biomarker has been established to guide further diagnostic or even therapeutic approaches, most likely due to insufficient validation, methodical complexity, or economic factors. COVID-19-associated coagulopathy is a hallmark of the disease and is mainly attributed to dysregulated immunothrombosis. This process describes an intricate interplay of platelets, innate immune cells, the coagulation cascade, and the vascular endothelium leading to both micro- and macrothrombotic complications. In this context, increased levels of immunothrombotic components, including platelet and platelet-leukocyte aggregates, have been described and linked to COVID-19 severity. METHODS Here, we describe a label-free quantitative phase imaging approach, allowing the identification of cell-aggregates and their components at single-cell resolution within 30 min, which prospectively qualifies the method as point-of-care (POC) testing. RESULTS We find a significant association between the severity of COVID-19 and the amount of platelet and platelet-leukocyte aggregates. Additionally, we observe a linkage between severity, aggregate composition, and size distribution of platelets in aggregates. CONCLUSIONS This study presents a POC-compatible method for rapid quantitative analysis of blood cell aggregates in patients with COVID-19.
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Affiliation(s)
- Christian Klenk
- Heinz-Nixdorf-Chair of Biomedical Electronics, School of Computation, Information and Technology, Technical University of Munich, TranslaTUM, 81675, Munich, Germany
| | - Johanna Erber
- TUM School of Medicine and Health, Department of Clinical Medicine - Clinical Department for Internal Medicine II, University Medical Centre, Technical University of Munich, 81675, Munich, Germany
| | - David Fresacher
- Heinz-Nixdorf-Chair of Biomedical Electronics, School of Computation, Information and Technology, Technical University of Munich, TranslaTUM, 81675, Munich, Germany
- Chair for Data Processing, School of Computation, Information and Technology, Technical University of Munich, 80333, Munich, Germany
| | - Stefan Röhrl
- Chair for Data Processing, School of Computation, Information and Technology, Technical University of Munich, 80333, Munich, Germany
| | - Manuel Lengl
- Chair for Data Processing, School of Computation, Information and Technology, Technical University of Munich, 80333, Munich, Germany
| | - Dominik Heim
- Heinz-Nixdorf-Chair of Biomedical Electronics, School of Computation, Information and Technology, Technical University of Munich, TranslaTUM, 81675, Munich, Germany
| | - Hedwig Irl
- TUM School of Medicine and Health, Department of Clinical Medicine - Clinical Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre, Technical University of Munich, 81675, Munich, Germany
| | - Martin Schlegel
- TUM School of Medicine and Health, Department of Clinical Medicine - Clinical Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre, Technical University of Munich, 81675, Munich, Germany
| | - Bernhard Haller
- TUM School of Medicine and Health, Department of Clinical Medicine - Institute of AI and Informatics in Medicine, University Medical Centre, Technical University of Munich, 81675, Munich, Germany
| | - Tobias Lahmer
- TUM School of Medicine and Health, Department of Clinical Medicine - Clinical Department for Internal Medicine II, University Medical Centre, Technical University of Munich, 81675, Munich, Germany
| | - Klaus Diepold
- Chair for Data Processing, School of Computation, Information and Technology, Technical University of Munich, 80333, Munich, Germany
| | - Sebastian Rasch
- TUM School of Medicine and Health, Department of Clinical Medicine - Clinical Department for Internal Medicine II, University Medical Centre, Technical University of Munich, 81675, Munich, Germany
| | - Oliver Hayden
- Heinz-Nixdorf-Chair of Biomedical Electronics, School of Computation, Information and Technology, Technical University of Munich, TranslaTUM, 81675, Munich, Germany.
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Vu V, Rossini L, del Alamo JC, Dembitsky W, Gray RA, May-Newman K. Benchtop Models of Patient-Specific Intraventricular Flow During Heart Failure and LVAD Support. J Biomech Eng 2023; 145:111010. [PMID: 37565996 PMCID: PMC10777504 DOI: 10.1115/1.4063147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023]
Abstract
The characterization of intraventricular flow is critical to evaluate the efficiency of fluid transport and potential thromboembolic risk but challenging to measure directly in advanced heart failure (HF) patients with left ventricular assist device (LVAD) support. The study aims to validate an in-house mock loop (ML) by simulating specific conditions of HF patients with normal and prosthetic mitral valves (MV) and LVAD patients with small and dilated left ventricle volumes, then comparing the flow-related indices result of vortex parameters, residence time (RT), and shear-activation potential (SAP). Patient-specific inputs for the ML studies included heart rate, end-diastolic and end-systolic volumes, ejection fraction, aortic pressure, E/A ratio, and LVAD speed. The ML effectively replicated vortex development and circulation patterns, as well as RT, particularly for HF patient cases. The LVAD velocity fields reflected altered flow paths, in which all or most incoming blood formed a dominant stream directing flow straight from the mitral valve to the apex. RT estimation of patient and ML compared well for all conditions, but SAP was substantially higher in the LVAD cases of the ML. The benchtop system generated comparable and reproducible hemodynamics and fluid dynamics for patient-specific conditions, validating its reliability and clinical relevance. This study demonstrated that ML is a suitable platform to investigate the fluid dynamics of HF and LVAD patients and can be utilized to investigate heart-implant interactions.
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Affiliation(s)
- Vi Vu
- Bioengineering Program, Department of Mechanical Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182;Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993
| | - Lorenzo Rossini
- Mechanical and Aerospace Engineering Department, University of California, San Diego 9500 Gilman Drive, La Jolla, CA 92093
| | - Juan C. del Alamo
- Center for Cardiovascular Biology & Mechanical Engineering Department, University of Washington, 1400 NE Campus Parkway, Seattle, WA 98195
| | - Walter Dembitsky
- Cardiothoracic Surgery, Mechanical Assist Program, Sharp Memorial Hospital, San Diego 7901 Frost Street, San Diego, CA 92123
| | - Richard A. Gray
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993
| | - Karen May-Newman
- Bioengineering Program, Department of Mechanical Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182
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Kizhisseri M, Gharaie S, Schluter J. An analytical method informed by clinical imaging data for estimating outlet boundary conditions in computational fluid dynamics analysis of carotid artery blood flow. Sci Rep 2023; 13:14973. [PMID: 37696859 PMCID: PMC10495450 DOI: 10.1038/s41598-023-42004-5] [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: 12/08/2022] [Accepted: 09/04/2023] [Indexed: 09/13/2023] Open
Abstract
Stroke occur mainly due to arterial thrombosis and rupture of cerebral blood vessels. Previous studies showed that blood flow-induced wall shear stress is an essential bio marker for estimating atherogenesis. It is a common practice to use computational fluid dynamics (CFD) simulations to calculate wall shear stress and to quantify blood flow. Reliability of predicted CFD results greatly depends on the accuracy of applied boundary conditions. Previously, the boundary conditions were estimated by varying values so that they matched the clinical data. It is applicable upon the availability of clinical data. Meanwhile, in most cases all that can be accessed are arterial geometry and inflow rate. Consequently, there is a need to devise a tool to estimate boundary values such as resistance and compliance of arteries. This study proposes an analytical framework to estimate the boundary conditions for a carotid artery based on the geometries of the downstream arteries available from clinical images.
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Affiliation(s)
- Muhsin Kizhisseri
- School of Engineering, Deakin University, 75 Pigdons Rd, Waurn Ponds, VIC, 3216, Australia.
| | - Saleh Gharaie
- School of Engineering, Deakin University, 75 Pigdons Rd, Waurn Ponds, VIC, 3216, Australia
| | - Jorg Schluter
- School of Engineering, Deakin University, 75 Pigdons Rd, Waurn Ponds, VIC, 3216, Australia
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7
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Xenakis A, Ruiz-Soler A, Keshmiri A. Multi-Objective Optimisation of a Novel Bypass Graft with a Spiral Ridge. Bioengineering (Basel) 2023; 10:489. [PMID: 37106676 PMCID: PMC10136357 DOI: 10.3390/bioengineering10040489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/04/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
The low long-term patency of bypass grafts is a major concern for cardiovascular treatments. Unfavourable haemodynamic conditions in the proximity of distal anastomosis are closely related to thrombus creation and lumen lesions. Modern graft designs address this unfavourable haemodynamic environment with the introduction of a helical component in the flow field, either by means of out-of-plane helicity graft geometry or a spiral ridge. While the latter has been found to lack in performance when compared to the out-of-plane helicity designs, recent findings support the idea that the existing spiral ridge grafts can be further improved in performance through optimising relevant design parameters. In the current study, robust multi-objective optimisation techniques are implemented, covering a wide range of possible designs coupled with proven and well validated computational fluid dynamics (CFD) algorithms. It is shown that the final set of suggested design parameters could significantly improve haemodynamic performance and therefore could be used to enhance the design of spiral ridge bypass grafts.
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Affiliation(s)
- Antonios Xenakis
- School of Engineering, The University of Manchester, Manchester M13 9PL, UK
| | - Andres Ruiz-Soler
- School of Engineering, The University of Manchester, Manchester M13 9PL, UK
| | - Amir Keshmiri
- School of Engineering, The University of Manchester, Manchester M13 9PL, UK
- Department of Cardiothoracic Surgery, Manchester University NHS Foundation Trust, Manchester M13 9WL, UK
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8
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Zhang T, Liu L, Huang X, Gao X, Chen D, Huan X, He C, Li Y. Effect of pathological high shear exposure time on platelet activation and aggregation. Clin Hemorheol Microcirc 2023:CH221567. [PMID: 37066902 DOI: 10.3233/ch-221567] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Circulating platelets are sometimes exposed to high shear rate environments due to vascular stenosis, and the effect of transiently elevated pathological high shear rates on platelet activation and aggregation function has not been clarified. The aim of this study was to investigate the effect of pathological high shear rate (8302s - 1) exposure time (3.16-25.3 ms) on platelet activation and aggregation function. In addition, by adding active ingredients of antiplatelet drugs such as ASA (an active ingredient of aspirin), Ticagrelor, Tirofiban and GP1BA (platelet membrane protein GPIb inhibitor) in vitro, we studied TXA2, P2Y12-ADP, GPIIb/IIIa-fibrinogen and GPIb /IX/V-vWF receptor pathways to determine platelet activation function mediated by pathological high shear rate. In this study, we designed a set of microfluidic chips with stenosis lengths of 0.5 mm, 1 mm, 2 mm, 3 mm, and 4 mm, all with 80% stenosis, to generate pathological high shear forces that can act at different times. The whole blood flowing through the microchannels was collected by perfusion of sodium citrate anticoagulated whole blood at a physiological arterial shear rate (1500 s - 1), and the expression levels of platelet surface activation markers (P-selectin and GP IIb/IIIa) and the degree of platelet aggregation were analyzed by flow cytometry; platelet aggregation patterns were observed by microscopic examination of blood smears. The results showed that shearing significantly increased platelet activation and aggregation levels compared to un-sheared whole blood, and the activation and aggregation levels increased with increasing duration of pathological high shear rate. In vitro inhibition studies showed that ASA barely inhibited the expression of P-selectin and PAC-1 on the platelet surface; Ticagrelor effectively inhibited the expression of both P-selectin and PAC-1; Tirofiban significantly inhibited the expression of PAC-1 on the platelet surface and slightly inhibited the expression of P-selectin; GP1BA significantly inhibited the expression of both.ur results suggest that transient pathological high shear rate (8302s - 1) exposure can induce platelet activation in a time-dependent manner; however, the mechanism is more complex and may be due to the following reasons: transient elevated pathological high shear rate activates platelets through the GPIb/IX/V-vWF receptor pathway, and after platelet activation, its surface membrane protein GPIIb/IIIa receptors activate platelets through fibrinogen to form platelet-platelet aggregates, and further activation of active substances such as ADP and TXA2 released by platelet alpha particles, which contribute to the formation of irreversible platelet aggregation.
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Affiliation(s)
- Tiancong Zhang
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Ling Liu
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Xiaojing Huang
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Xuemei Gao
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Dan Chen
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Xuanrong Huan
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Cui He
- Department of Blood Transfusion of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Yuan Li
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
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9
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Aggarwal A, Jennings CL, Manning E, Cameron SJ. Platelets at the Vessel Wall in Non-Thrombotic Disease. Circ Res 2023; 132:775-790. [PMID: 36927182 PMCID: PMC10027394 DOI: 10.1161/circresaha.122.321566] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 02/15/2023] [Indexed: 03/18/2023]
Abstract
Platelets are small, anucleate entities that bud from megakaryocytes in the bone marrow. Among circulating cells, platelets are the most abundant cell, traditionally involved in regulating the balance between thrombosis (the terminal event of platelet activation) and hemostasis (a protective response to tissue injury). Although platelets lack the precise cellular control offered by nucleate cells, they are in fact very dynamic cells, enriched in preformed RNA that allows them the capability of de novo protein synthesis which alters the platelet phenotype and responses in physiological and pathological events. Antiplatelet medications have significantly reduced the morbidity and mortality for patients afflicted with thrombotic diseases, including stroke and myocardial infarction. However, it has become apparent in the last few years that platelets play a critical role beyond thrombosis and hemostasis. For example, platelet-derived proteins by constitutive and regulated exocytosis can be found in the plasma and may educate distant tissue including blood vessels. First, platelets are enriched in inflammatory and anti-inflammatory molecules that may regulate vascular remodeling. Second, platelet-derived microparticles released into the circulation can be acquired by vascular endothelial cells through the process of endocytosis. Third, platelets are highly enriched in mitochondria that may contribute to the local reactive oxygen species pool and remodel phospholipids in the plasma membrane of blood vessels. Lastly, platelets are enriched in proteins and phosphoproteins which can be secreted independent of stimulation by surface receptor agonists in conditions of disturbed blood flow. This so-called biomechanical platelet activation occurs in regions of pathologically narrowed (atherosclerotic) or dilated (aneurysmal) vessels. Emerging evidence suggests platelets may regulate the process of angiogenesis and blood flow to tumors as well as education of distant organs for the purposes of allograft health following transplantation. This review will illustrate the potential of platelets to remodel blood vessels in various diseases with a focus on the aforementioned mechanisms.
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Affiliation(s)
- Anu Aggarwal
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland, Ohio
| | - Courtney L. Jennings
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland, Ohio
| | - Emily Manning
- Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Scott J. Cameron
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland, Ohio
- Heart Vascular and Thoracic Institute, Department of Cardiovascular Medicine, Section of Vascular Medicine, Cleveland Clinic Foundation, Cleveland, Ohio, USA
- Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Hematology, Taussig Cancer Center, Cleveland, Ohio
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10
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Hill SJ, Young A, Prendergast B, Redwood S, Rajani R, De Vecchi A. Patient-specific fluid simulation of transcatheter mitral valve replacement in mitral annulus calcification. Front Cardiovasc Med 2022; 9:934305. [PMID: 36588546 PMCID: PMC9797989 DOI: 10.3389/fcvm.2022.934305] [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: 05/02/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022] Open
Abstract
Introduction Transcatheter mitral valve replacement is a promising alternative to open-heart surgery in elderly patients. Patients with severe mitral annulus calcification (MAC) are a particularly high-risk population, where postprocedural complications can have catastrophic effects. Amongst these, obstruction of the left ventricular outflow tract can lead to ventricular hypertrophic remodeling and subsequent heart failure, while subclinical valve thrombosis can result in early bioprosthetic valve failure. Methods To elucidate the mechanisms of left ventricular outflow tract obstruction and valve thrombosis following valve-in-MAC procedures, we used image processing and Computational Fluid Dynamics (CFD) software to generate patient- and device-specific models based on preprocedural CT data. Personalized computer simulations were performed to predict the left ventricular haemodynamics after implantation in three patients with severe MAC. Results The simulations have successfully captured the increased pressure gradient in the left ventricular outflow tract as a result of the partial obstruction due to the implanted valve. Regions of wall shear stress above the threshold value for platelet activation were also observed on the bioprosthetic frame as a result of the reduced outflow tract area, which led to increases in flow resistance and blood residence time inside the ventricle. Consistent with these findings, areas of slow recirculating flow and blood stasis formed near the valve frame, creating potential pro-thrombotic conditions. Discussion This study provides insight into the relationship between size and shape of the outflow tract post-implantation, pressure gradients and pro-thrombotic flow metrics such as wall shear stress and blood residence time. Results show the potential of CFD modeling to bring key functional metrics into preprocedural assessment for a comprehensive evaluation of post-procedural risks beyond anatomical factors. Following further validation and extension to the atrial chamber, this approach can provide an in-depth analysis of the likelihood of valvular thrombosis.
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Affiliation(s)
- Samuel Joseph Hill
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Alistair Young
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Bernard Prendergast
- Cardiovascular Directorate, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Simon Redwood
- Cardiovascular Directorate, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Ronak Rajani
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Adelaide De Vecchi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
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11
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Salikhova TY, Pushin DM, Nesterenko IV, Biryukova LS, Guria GT. Patient specific approach to analysis of shear-induced platelet activation in haemodialysis arteriovenous fistula. PLoS One 2022; 17:e0272342. [PMID: 36191008 PMCID: PMC9529124 DOI: 10.1371/journal.pone.0272342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 07/19/2022] [Indexed: 11/29/2022] Open
Abstract
Shear-induced platelet activation (SIPAct) is an important mechanism of thrombosis initiation under high blood flow. This mechanism relies on the interaction of platelets with the von Willebrand factor (VWF) capable of unfolding under high shear stress. High shear stress occurs in the arteriovenous fistula (AVF) commonly used for haemodialysis. A novel patient-specific approach for the modelling of SIPAct in the AVF was proposed. This enabled us to estimate the SIPAct level via computational fluid dynamics. The suggested approach was applied for the SIPAct analysis in AVF geometries reconstructed from medical images. The approach facilitates the determination of the SIPAct level dependence on both biomechanical (AVF flow rate) and biochemical factors (VWF multimer size). It was found that the dependence of the SIPAct level on the AVF flow rate can be approximated by a power law. The critical flow rate was a decreasing function of the VWF multimer size. Moreover, the critical AVF flow rate highly depended on patient-specific factors, e.g., the vessel geometry. This indicates that the approach may be adopted to elucidate patient-specific thrombosis risk factors in haemodialysis patients.
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Affiliation(s)
- Tatiana Yu Salikhova
- National Medical Research Center for Hematology, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Denis M. Pushin
- National Medical Research Center for Hematology, Moscow, Russia
| | | | | | - Georgy Th Guria
- National Medical Research Center for Hematology, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- * E-mail:
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12
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Han D, Zhang J, Griffith BP, Wu ZJ. Models of Shear-Induced Platelet Activation and Numerical Implementation With Computational Fluid Dynamics Approaches. J Biomech Eng 2022; 144:1119644. [PMID: 34529037 DOI: 10.1115/1.4052460] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 12/17/2022]
Abstract
Shear-induced platelet activation is one of the critical outcomes when blood is exposed to elevated shear stress. Excessively activated platelets in the circulation can lead to thrombus formation and platelet consumption, resulting in serious adverse events such as thromboembolism and bleeding. While experimental observations reveal that it is related to the shear stress level and exposure time, the underlying mechanism of shear-induced platelet activation is not fully understood. Various models have been proposed to relate shear stress levels to platelet activation, yet most are modified from the empirically calibrated power-law model. Newly developed multiscale platelet models are tested as a promising approach to capture a single platelet's dynamic shape during activation, but it would be computationally expensive to employ it for a large-scale analysis. This paper summarizes the current numerical models used to study the shear-induced platelet activation and their computational applications in the risk assessment of a particular flow pattern and clot formation prediction.
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Affiliation(s)
- Dong Han
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201
| | - Bartley P Griffith
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201
| | - Zhongjun J Wu
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201; Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD 20742
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13
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Effect of Extended Lipid Core on the Hemodynamic Parameters: A Fluid-Structure Interaction Approach. Appl Bionics Biomech 2022; 2022:2047549. [PMID: 35342456 PMCID: PMC8947935 DOI: 10.1155/2022/2047549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 02/28/2022] [Indexed: 11/17/2022] Open
Abstract
Myocardial infarction is one of the leading causes of death in the developed countries. A majority of myocardial infarctions are caused by the rupture of coronary artery plaques. In order to achieve a better understanding of the effect of the extension of the lipid core into the artery wall on the change of flow field and its effect on plaque vulnerability, we have studied the hemodynamic parameters by utilizing a finite element method and taking into account the fluid-structure interaction (FSI). Four groups of stenosis models with different sizes of lipid core were used in the study. The fully developed pulsatile velocity profile of the right coronary artery was used as the inlet boundary condition, and the pressure pulse was applied as the outlet boundary condition. The non-Newtonian Carreau model was used to simulate the non-Newtonian behavior of blood. Results indicate that the extension of the lipid core into the artery wall influences the flow field; subsequently, creates favorable conditions for additional development of the lipid core which can lead to a higher risk of plaque rupture.
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14
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Ahmed M, Gupta N, Jana R, Das M, Kar PK. Ramifications of Vorticity on Aggregation and Activation of Platelets in Bi-Leaflet Mechanical Heart Valve: Fluid-Structure-Interaction Study. J Biomech Eng 2022; 144:1133337. [PMID: 35079764 DOI: 10.1115/1.4053665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Indexed: 11/08/2022]
Abstract
Bileaflet Mechanical Heart Valves (BMHV) are widely implanted to replace diseased heart valves. Despite many improvements in design, these valves still suffer from various complications, such as valve dysfunction, tissue overgrowth, hemolysis, and thromboembolism. Thrombosis and thromboembolism are believed to be initiated by platelet activation due to contact with foreign surfaces and non-physiological flow patterns. The implantation of the valve causes non-physiological patterns of vortex shedding behind the leaflets. The present study signifies the importance of vorticity in platelet activation and aggregation in BMHV implants. A two-phase model with the first Eulerian phase for blood and the second Discrete phase for platelets are used here. The generalized cross model of viscosity has been used to simulate the non-Newtonian viscosity of blood. A Fluid-Structure-Interaction model has been used to simulate the motion of leaflets. The present study has also estimated Platelet Activation State (PAS), which is the mathematical estimation of the degree of activation of platelets due to flow-induced shear stresses that cause thrombus formation. The regions in the fluid domain with a higher vorticity field have been found to contain platelets with relatively higher PAS than regions with relatively lower vorticity fields. Also, this study has quantitatively reported the effect of vorticity on platelet aggregation. The densities of platelets in the fluid areas with higher vorticity fields are higher than densities in the fluid regions with relatively lower vorticity fields, which indicate aggregation of highly activated platelets in areas with somewhat higher vorticity.
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Affiliation(s)
- Meraj Ahmed
- Advanced Nanoengineering Materials Laboratory, Department of Mechanical Engineering, IIT-Kanpur, Kanpur-208016, UP, India
| | - Nirmal Gupta
- Department of Cardiovascular and Thoracic Surgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences of Mechanical Engineering, Lucknow-226014, UP, India
| | - Rashmoni Jana
- Department of Anatomy, Vardhman Mahavir Medical College and Safdarjung Hospital (VMMC and SJH), New Delhi-110029, New Delhi, India
| | - Malay Das
- Department of Mechanical Engineering, IIT-Kanpur, Kanpur-208016, UP, India
| | - Prof Kamal Kar
- Advanced Nanoengineering Materials Laboratory, Department of Mechanical Engineering, IIT-Kanpur, Kanpur-208016, UP, India; Advanced Nanoengineering Materials Laboratory, Materials Science Program, IIT-Kanpur, Kanpur-208016, UP, India
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15
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Non-coding RNA suppresses FUS aggregation caused by mechanistic shear stress on pipetting in a sequence-dependent manner. Sci Rep 2021; 11:9523. [PMID: 33947944 PMCID: PMC8096841 DOI: 10.1038/s41598-021-89075-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/20/2021] [Indexed: 11/29/2022] Open
Abstract
Fused in sarcoma/translocated in liposarcoma (FUS/TLS) is a multitasking RNA/DNA binding protein. FUS aggregation is implicated in various neurodegenerative diseases. RNA was suggested to modulate phase transition of FUS. Here, we found that FUS transforms into the amorphous aggregation state as an instant response to the shear stress caused by usual pipetting even at a low FUS concentration, 100 nM. It was revealed that non-coding RNA can suppress the transformation of FUS into aggregates. The suppressive effect of RNA on FUS aggregation is sequence-dependent. These results suggested that the non-coding RNA could be a prospective suppressor of FUS aggregation caused by mechanistic stress in cells. Our finding might pave the way for more research on the role of RNAs as aggregation inhibitors, which could facilitate the development of therapies for neurodegenerative diseases.
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Abstract
The success of left ventricular assist device (LVAD) therapy is hampered by complications such as thrombosis and bleeding. Understanding blood flow interactions between the heart and the LVAD might help optimize treatment and decrease complication rates. We hypothesized that LVADs modify shear stresses and blood transit in the left ventricle (LV) by changing flow patterns and that these changes can be characterized using 2D echo color Doppler velocimetry (echo-CDV). We used echo-CDV and custom postprocessing methods to map blood flow inside the LV in patients with ongoing LVAD support (Heartmate II, N = 7). We compared it to healthy controls (N = 20) and patients with dilated cardiomyopathy (DCM, N = 20). We also analyzed intraventricular flow changes during LVAD ramp tests (baseline ± 400 rpm). LVAD support reversed the increase in blood stasis associated with DCM, but it did not reduce intraventricular shear exposure. Within the narrow range studied, the ventricular flow was mostly insensitive to changes in pump speed. Patients with significant aortic insufficiency showed abnormalities in blood stasis and shear indices. Overall, this study suggests that noninvasive flow imaging could potentially be used in combination with standard clinical methods for adjusting LVAD settings to optimize flow transport and minimize stasis on an individual basis.
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Bozzi S, Vesentini S, Santus M, Ghelli N, Fontanili P, Corbelli M, Fiore GB, Redaelli ACL. Fluid dynamics characterization and thrombogenicity assessment of a levitating centrifugal pump with different impeller designs. Med Eng Phys 2020; 83:26-33. [PMID: 32807345 DOI: 10.1016/j.medengphy.2020.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 11/16/2022]
Abstract
Technical guidelines nowadays recommend and regulate the use Computational Fluid Dynamics (CFD) to assess the performance of medical devices. CFD coupled to blood damage models has emerged as a powerful tool to evaluate the hemocompatibility of blood recirculating devices. The present study is aimed at evaluating the hydrodynamic performance and the thrombogenic potential of two prototypes of magnetically levitating centrifugal pumps. The two devices differ in the impeller configuration - 6-blades vs. 12-blades - and have been designed to be used in Cardiopulmonary Bypass (CPB) circuits during open heart surgery and in Extracorporeal Membrane Oxygenation (ECMO) to support patients with severe cardiac or respiratory failure. The pumps have been modelled using Direct Numerical Simulation coupled to Lagrangian analysis to predict platelet activation due to abnormal shear stress histories. Numerical results have been compared with experimental data in terms of head generation for different working points. Results show that the 6-blades pump has i) smaller stagnation areas, ii) lower stress levels and iii) higher strain rate, resulting in a lower thrombogenic potential, whereas the 12-blade impeller guarantees a more stable performance at high flow rates, suggesting its preferential use for more demanding applications, such as CPB.
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Affiliation(s)
- Silvia Bozzi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
| | - Simone Vesentini
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Marco Santus
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Nicola Ghelli
- EUROSETS S.r.l., Strada Statale 12, no143, 41036 Medolla (MO), Italy
| | - Paolo Fontanili
- EUROSETS S.r.l., Strada Statale 12, no143, 41036 Medolla (MO), Italy
| | - Marco Corbelli
- EUROSETS S.r.l., Strada Statale 12, no143, 41036 Medolla (MO), Italy
| | - Gianfranco B Fiore
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Alberto C L Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
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18
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Pushin DM, Salikhova TY, Zlobina KE, Guria GT. Platelet activation via dynamic conformational changes of von Willebrand factor under shear. PLoS One 2020; 15:e0234501. [PMID: 32525962 PMCID: PMC7289367 DOI: 10.1371/journal.pone.0234501] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/26/2020] [Indexed: 01/10/2023] Open
Abstract
Shear-induced conformational changes of von Willebrand factor (VWF) play an important role in platelet activation. A novel approach describing VWF unfolding on the platelet surface under dynamic shear stress is proposed. Cumulative effect of dynamic shear on platelet activation via conformational changes of VWF is analysed. The critical condition of shear-induced platelet activation is formulated. The explicit expression for the threshold value of cumulative shear stress as a function of VWF multimer size is derived. The results open novel prospects for pharmacological regulation of shear-induced platelet activation through control of VWF multimers size distribution.
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Affiliation(s)
- Denis M. Pushin
- National Research Center for Hematology, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | | | | | - Georgy Th. Guria
- National Research Center for Hematology, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
- * E-mail:
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19
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Hatoum H, Gooden S, Heitkemper M, Blum KM, Zakko J, Bocks M, Yi T, Wu YL, Wang Y, Breuer CK, Dasi LP. Fetal Transcatheter Trileaflet Heart Valve Hemodynamics: Implications of Scaling on Valve Mechanics and Turbulence. Ann Biomed Eng 2020; 48:1683-1693. [PMID: 32052320 PMCID: PMC7286783 DOI: 10.1007/s10439-020-02475-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 02/05/2020] [Indexed: 01/09/2023]
Abstract
The scarcity of data available on the best approach for pulmonary fetal valve replacement or implantation necessitate an investigation on whether practices using adult transcatheter valves could be translated to fetal applications. The objective of this study is to evaluate the hemodynamic characteristics and the turbulent properties of a fetal sized trileaflet transcatheter pulmonary valve in comparison with an adult balloon-expandable valve in order to assess the possibility of designing valves for fetal applications using dynamic similarity. A 6 mm fetal trileaflet valve and a 26 mm SAPIEN 3 valve were assessed in a pulse duplicator. Particle image velocimetry was performed. Pressure gradient (ΔP), effective orifice area (EOA), regurgitant fractions (RF), pinwheeling indices (PI) and turbulent stresses were evaluated. ΔP was 8.56 ± 0.139 and 7.76 ± 0.083 mmHg with fetal valve and SAPIEN respectively (p < 0.0001); EOA was 0.10 ± 0.0007 and 2.1 ± 0.025 cm2 with fetal valve and SAPIEN respectively (p < 0.0001); RF with the fetal valve was 2.35 ± 1.99% and with SAPIEN 10.92 ± 0.11% (p < 0.0001); PI with fetal valve was 0.404 ± 0.01 and with SAPIEN 0.37 ± 0.07; The flow regime with the fetal valve was turbulent and Reynolds numbers reached about 7000 while those with the SAPIEN reached about 20,000 at peak velocity. Turbulent stresses were significantly higher with fetal valve compared with SAPIEN. Instantaneous viscous shear stresses with fetal valve were 5.8 times higher than those obtained with SAPIEN and Reynolds shear stresses were 2.5 times higher during peak systole. The fetal valve implantation leads to a turbulent flow (specific to this particular type and design of valve) regime unlike what is expected of a small valve with different flow properties compared to adult valves.
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Affiliation(s)
- Hoda Hatoum
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle NW, Atlanta, GA, 30313, USA
| | - Shelley Gooden
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle NW, Atlanta, GA, 30313, USA
| | - Megan Heitkemper
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Kevin M Blum
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Jason Zakko
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Martin Bocks
- Case Western Reserve University School of Medicine, UH Rainbow Babies & Children's Hospital, Cleveland, OH, USA
| | - Tai Yi
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Yen-Lin Wu
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Yadong Wang
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Christopher K Breuer
- Center for Regenerative Medicine, Tissue Engineering Program, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Lakshmi Prasad Dasi
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle NW, Atlanta, GA, 30313, USA.
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20
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Chivukula VK, Beckman JA, Prisco AR, Lin S, Dardas TF, Cheng RK, Farris SD, Smith JW, Mokadam NA, Mahr C, Aliseda A. Small Left Ventricular Size Is an Independent Risk Factor for Ventricular Assist Device Thrombosis. ASAIO J 2020; 65:152-159. [PMID: 29677037 DOI: 10.1097/mat.0000000000000798] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The prevalence of ventricular assist device (VAD) therapy has continued to increase due to a stagnant donor supply and growing advanced heart failure (HF) population. We hypothesize that left ventricular (LV) size strongly influences biocompatibility and risk of thrombosis. Unsteady computational fluid dynamics (CFD) was used in conjunction with patient-derived computational modeling and virtual surgery with a standard, apically implanted inflow cannula. A dual-focus approach of evaluating thrombogenicity was employed: platelet-based metrics to characterize the platelet environment and flow-based metrics to investigate hemodynamics. Left ventricular end-diastolic dimensions (LVEDds) ranging from 4.5 to 6.5 cm were studied and ranked according to relative thrombogenic potential. Over 150,000 platelets were individually tracked in each LV model over 15 cardiac cycles. As LV size decreased, platelets experienced markedly increased shear stress histories (SHs), whereas platelet residence time (RT) in the LV increased with size. The complex interplay between increased SH and longer RT has profound implications on thrombogenicity, with a significantly higher proportion of platelets in small LVs having long RT times and being subjected to high SH, contributing to thrombus formation. Our data suggest that small LV size, rather than decreased VAD speed, is the primary pathologic mechanism responsible for the increased incidence of thrombosis observed in VAD patients with small LVs.
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Affiliation(s)
| | | | - Anthony R Prisco
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Shin Lin
- Division of Cardiology, University of Washington, Seattle, Washington
| | - Todd F Dardas
- Division of Cardiology, University of Washington, Seattle, Washington
| | - Richard K Cheng
- Division of Cardiology, University of Washington, Seattle, Washington
| | - Stephen D Farris
- Division of Cardiology, University of Washington, Seattle, Washington
| | - Jason W Smith
- Division of Cardiothoracic Surgery, University of Washington, Seattle, Washington
| | - Nahush A Mokadam
- Division of Cardiothoracic Surgery, University of Washington, Seattle, Washington
| | - Claudius Mahr
- Division of Cardiology, University of Washington, Seattle, Washington
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21
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Von Volkmann HL, Brønstad I, Fiskerstrand T, Gudbrandsen OA. Comparison of pre-analytical conditions for quantification of serotonin in platelet-poor plasma. Pract Lab Med 2019; 17:e00136. [PMID: 31649988 PMCID: PMC6804510 DOI: 10.1016/j.plabm.2019.e00136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/08/2019] [Accepted: 09/17/2019] [Indexed: 01/07/2023] Open
Abstract
Background Reported concentrations of serotonin in platelet-poor plasma (PPP) in healthy subjects vary widely due to different pre-analytical procedures. Aim To examine how different pre-analytical conditions affect the measured concentration of serotonin in PPP. Method Six pre-analytical protocols were compared for preparation of PPP from EDTA whole blood for quantification of serotonin from nine healthy individuals. Three combinations of centrifugation with a mild centrifugation of gel-free EDTA tubes followed by a stronger centrifugation were compared to single-stage centrifugation of EDTA tubes with separator gel and heat shock treatment of blood prior to centrifugation. All samples were analysed using the same enzyme linked immunosorbent assay (ELISA) method. Results Findings show that two consecutive centrifugations; first a mild centrifugation at 100 or 200×g followed by centrifugation at 4500 or 14500×g resulted in the lowest serotonin concentration in PPP. Conclusion Two successive centrifugations to produce PPP for serotonin analysis; first a mild centrifugation to avoid mechanical stress on the platelets, and next a stronger centrifugation to remove platelets, is superior to the use of gel tubes and heat shock treatment.
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Affiliation(s)
- Hilde L. Von Volkmann
- National Centre for Ultrasound in Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Ingeborg Brønstad
- National Centre for Ultrasound in Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Torunn Fiskerstrand
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Oddrun Anita Gudbrandsen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Corresponding author. Department of Clinical Science, University of Bergen, 5021, Bergen, Norway.
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22
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Khodaee F, Barakat M, Abbasi M, Dvir D, Azadani AN. Incomplete expansion of transcatheter aortic valves is associated with propensity for valve thrombosis. Interact Cardiovasc Thorac Surg 2019; 30:39-46. [DOI: 10.1093/icvts/ivz213] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/24/2019] [Accepted: 08/04/2019] [Indexed: 11/14/2022] Open
Abstract
Abstract
OBJECTIVES
Clinical and subclinical leaflet thromboses are increasingly recognized complications following transcatheter aortic valve replacement. Identification of the risk factors is important to mitigate the occurrence of leaflet thrombosis in transcatheter aortic valves (TAVs) and ensure their long-term function. The goal of this study was to determine the effect of incomplete expansion of TAVs on the likelihood of leaflet thrombosis following transcatheter aortic valve replacement.
METHODS
Using experimental and computational methods, 3-dimensional unsteady flow fields of 26-mm SAPIEN 3 valves expanded to 3 different diameters (i.e. 26.0 mm, 23.4 mm and 20.8 mm) were determined in patient-specific geometries. The diameters corresponded to 100%, 90% and 80% stent expansion, respectively. To address the potential difference in the likelihood of leaflet thrombosis, blood residence time (i.e. stasis) and viscous shear stress on the surface of TAV leaflets were quantified and compared.
RESULTS
The results indicated that TAV underexpansion increased blood stasis on the TAV leaflets. Blood residence time on the surface of the leaflets after 80% and 90% TAV expansion on average was 9.4% and 4.1% more than that of the fully expanded TAV, respectively. In addition, areas of blood stasis time of more than 0.5 s, which are highly prone to platelet activation, increased linearly as the degree of TAV underexpansion increased.
CONCLUSIONS
Incomplete expansion of TAVs increases blood stasis on the surface of TAV leaflets. Regions of blood stasis promote platelet activation and thrombotic events. TAV underexpansion can therefore increase the risk of leaflet thrombosis in patients with transcatheter aortic valve replacement.
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Affiliation(s)
- Farhan Khodaee
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Mohammed Barakat
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Mostafa Abbasi
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
| | - Danny Dvir
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Ali N Azadani
- The DU Cardiovascular Biomechanics Laboratory, Department of Mechanical and Materials Engineering, University of Denver, Denver, CO, USA
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23
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Left Ventricular Assist Device Inflow Cannula Insertion Depth Influences Thrombosis Risk. ASAIO J 2019; 66:766-773. [DOI: 10.1097/mat.0000000000001068] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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24
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Ex vivo assessment of bicuspidization repair in treating severe functional tricuspid regurgitation: a stereo-scopic PIV study. Sci Rep 2019; 9:11504. [PMID: 31395907 PMCID: PMC6687742 DOI: 10.1038/s41598-019-47873-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 06/24/2019] [Indexed: 11/22/2022] Open
Abstract
There has been a resurgence of interest in the treatment of severe functional tricuspid regurgitation (FTR) due to the awareness of its poor outcomes and potential percutaneous therapies. Kay bicuspidization has been adapted in percutaneous therapies but its clinical outcome remains uncertain. The present study evaluates the efficacy of Kay repair in a novel ex vivo pulsatile system. Porcine tricuspid valve (TV) (n = 3) was extracted and incorporated into a patient-specific silicon right ventricle (RV) emulating severe FTR, on which Kay repair was subsequently performed. TV area metrics and RV hemodynamic assessment by means of stereo-scopic particle image velocimetry were quantified in both FTR and post-repair conditions. Bicuspidization led to significant increase in cardiac output although the overall increment due to this approach alone was generally small, possibly due to existence of residual TR and the large reduction in TV opening area. Kinetic energy and viscous loss levels were increased post-repair, especially during diastolic filling. Main vortex structures generally maintained post-procedural. However, there was enhanced swirling motion in larger RV domain. Although this might reduce mural-thrombus risk, the relatively more complex vortex phenomenon likely resulted in elevated viscous loss observed and may potentially impact long-term adaptation. The RV hemodynamic alteration after tricuspid repair could be used to predict the success of these future transcatheter solutions.
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25
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Chivukula VK, Beckman JA, Prisco AR, Dardas T, Lin S, Smith JW, Mokadam NA, Aliseda A, Mahr C. Left Ventricular Assist Device Inflow Cannula Angle and Thrombosis Risk. Circ Heart Fail 2019; 11:e004325. [PMID: 29666072 DOI: 10.1161/circheartfailure.117.004325] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 02/26/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND As heart failure prevalence continues to increase in the setting of a static donor supply, left ventricular assist device (LVAD) therapy for end-stage heart failure continues to grow. Anecdotal evidence suggests that malalignment of the LVAD inflow cannula may increase thrombosis risk, but this effect has not been explored mechanistically or quantified statistically. Our objective is to elucidate the impact of surgical angulation of the inflow cannula on thrombogenicity. METHODS AND RESULTS Unsteady computational fluid dynamics is used in conjunction with computational modeling and virtual surgery to model flow through the left ventricle for 5 different inflow cannula angulations. We use a holistic approach to evaluate thrombogenicity: platelet-based (Lagrangian) metrics to evaluate the platelet mechanical environment, combined with flow-based (Eulerian) metrics to investigate intraventricular hemodynamics. The thrombogenic potential of each LVAD inflow cannula angulation is quantitatively evaluated based on platelet shear stress history and residence time. Intraventricular hemodynamics are strongly influenced by LVAD inflow cannula angulation. Platelet behavior indicates elevated thrombogenic potential for certain inflow cannula angles, potentially leading to platelet activation. Our analysis demonstrates that the optimal range of inflow angulation is within 0±7° of the left ventricular apical axis. CONCLUSIONS Angulation of the inflow cannula >7° from the apical axis (axis connecting mitral valve and ventricular apex) leads to markedly unfavorable hemodynamics as determined by computational fluid dynamics. Computational hemodynamic simulations incorporating Lagrangian and Eulerian metrics are a powerful tool for studying optimization of LVAD implantation strategies, with the long-term potential of improving outcomes.
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Affiliation(s)
- Venkat Keshav Chivukula
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Jennifer A Beckman
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Anthony R Prisco
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Todd Dardas
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Shin Lin
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Jason W Smith
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Nahush A Mokadam
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Alberto Aliseda
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.)
| | - Claudius Mahr
- Department of Mechanical Engineering (V.K.C., A.A.), Division of Cardiology (J.A.B., T.D., S.L., C.M.), and Division of Cardiothoracic Surgery (J.W.S., N.A.M.), University of Washington, Seattle. Department of Medicine, University of Minnesota, Minneapolis (A.R.P.).
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Heitkemper M, Hatoum H, Dasi LP. In vitro hemodynamic assessment of a novel polymeric transcatheter aortic valve. J Mech Behav Biomed Mater 2019; 98:163-171. [PMID: 31238208 DOI: 10.1016/j.jmbbm.2019.06.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 06/06/2019] [Accepted: 06/17/2019] [Indexed: 01/12/2023]
Abstract
Transcatheter aortic valve replacement (TAVR) is a life-saving alternative to surgical intervention. However, the identification of features associated with poor outcomes, including residual paravalvular leakage (PVL), leaflet calcification, and subclinical leaflet thrombosis, are cause to be concerned about valve durablilty (Mylotte and Piazza, 2015a, 2015b; Dasi et al., 2017; Makkar et al., 2015; Kheradvar et al., 2015a). The aim of this study is to optimize the potential of a hyaluronan (HA) enhanced polymeric transcatheter aortic valve (HA-TAV) that has promised to reduce blood damage causing-turbulent flow while maintaining durability. HA-enhanced linear low-density polyethylene (LLDPE) leaflets were sutured to novel cobalt chromium stents, size 26 mm balloon expandable stents. Hemodynamic performance was assessed in a left heart simulator under physiological pressure and flow conditions and compared to a 26 mm Medtronic Evolut and 26 mm Edwards SAPIEN 3. High-speed imaging and particle image velocimetry (PIV) were performed. The HA-TAV demonstrated an effective orifice area (EOA) within one standard deviation of the leading valve, SAPIEN 3.The regurgitant fraction (RF) of the HA-TAV (11.23 ± 0.55%) is decreased in comparison the Evolut (15.74 ± 0.73%) and slightly higher than the SAPIEN 3 (10.92 ± 0.11%), which is considered trace regurgitation according to valve standards. A decreased number of higher principal Reynolds shear stresses were shown for the HA-TAV at each cardiac phase. The HA-TAV is directly comparable and in some cases superior to the leading commercially available prosthetic heart valves in in-vitro hemodynamic testing.
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Affiliation(s)
- Megan Heitkemper
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA; Department of Mechanical Engineering, The Ohio State University, Columbus, OH, USA
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
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Benito Y, Martinez-Legazpi P, Rossini L, Pérez del Villar C, Yotti R, Martín Peinador Y, Rodríguez-Pérez D, Desco MM, Medrano C, Antoranz JC, Fernández-Avilés F, del Álamo JC, Bermejo J. Age-Dependence of Flow Homeostasis in the Left Ventricle. Front Physiol 2019; 10:485. [PMID: 31105588 PMCID: PMC6498893 DOI: 10.3389/fphys.2019.00485] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/08/2019] [Indexed: 11/29/2022] Open
Abstract
Background: Intracardiac flow homeostasis requires avoiding blood stasis and platelet activation during its transit through the cardiac chambers. However, the foundations of intraventricular blood washout and its exposure to shear stresses have been poorly addressed. We aimed to characterize and quantify these features in a wide population of healthy subjects and assess the relationships of these indices with age. Methods: We used color-Doppler echocardiography and custom post-processing methods to study 149 healthy volunteers from 26 days to 80 years old. From the intraventricular flow-velocity fields we obtained personalized maps of (1) the residence time of blood in the LV, and (2) the shear index, a metric accounting for the strongest occurrence of shear stresses inside the chamber. From these maps we derived quantitative indices of the overall intraventricular blood washout and shear exposure. We addressed the age-dependence of these indices and analyzed their relationship with age-related changes in filling-flow. Results: The entire intraventricular blood pool was replaced before 8 cycles. Average residence time of blood inside the LV was <3 cycles in all subjects and followed an inverse U-shape relationship with age, increasing from median (IQR) of 1.0 (0.7 to 1.2) cycles in the 1st year of life to 1.8 (1.4-2.2) cycles in young adults (17-30 years old), becoming shorter again thereafter. Shear index showed no relation with age and was bounded around 20 dyn·s/cm2. Regions with the longest residence time and highest shear index were identified near the apex. Differences in the degree of apical penetration of the filling waves and the duration of the late-filling phase explained the age-dependence of residence time (R adj 2 = 0.48, p < 0.001). Conclusions: In average, blood spends 1 to 3 beats inside the LV with very low shear stress rates. The apical region is the most prone to blood stasis, particularly in mid-aged adults. The washout of blood in the normal LV is age-dependent due to physiological changes in the degree of apical penetration of the filling waves.
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Affiliation(s)
- Yolanda Benito
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
| | - Pablo Martinez-Legazpi
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
| | - Lorenzo Rossini
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Candelas Pérez del Villar
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
| | - Raquel Yotti
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
| | - Yolanda Martín Peinador
- Centro de Salud Goya, Dirección Asistencial Centro, Atención Primaria de Madrid, Madrid, Spain
| | - Daniel Rodríguez-Pérez
- Department of Mathematical Physics and Fluids, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - M. Mar Desco
- Department of Mathematical Physics and Fluids, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Constancio Medrano
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
| | - Jose Carlos Antoranz
- Department of Mathematical Physics and Fluids, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Francisco Fernández-Avilés
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
| | - Juan C. del Álamo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA, United States
- Institute for Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Javier Bermejo
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Gregorio Marañón and CIBERCV, Madrid, Spain
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Efficiently Generating Mixing by Combining Differing Small Amplitude Helical Geometries. FLUIDS 2019. [DOI: 10.3390/fluids4020059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Helical geometries have been used in recent years to form cardiovascular prostheses such as stents and shunts. The helical geometry has been found to induce swirling flow, promoting in-plane mixing. This is hypothesised to reduce the formation of thrombosis and neo-intimal hyperplasia, in turn improving device patency and reducing re-implantation rates. In this paper we investigate whether joining together two helical geometries, of differing helical radii, in a repeating sequence, can produce significant gains in mixing effectiveness, by embodying a ‘streamline crossing’ flow environment. Since the computational cost of calculating particle trajectories over extended domains is high, in this work we devised a procedure for efficiently exploring the large parameter space of possible geometry combinations. Velocity fields for the single geometries were first obtained using the spectral/hp element method. These were then discontinuously concatenated, in series, for the particle tracking based mixing analysis of the combined geometry. Full computations of the most promising combined geometries were then performed. Mixing efficiency was evaluated quantitatively using Poincaré sections, particle residence time data, and information entropy. Excellent agreement was found between the idealised (concatenated flow field) and the full simulations of mixing performance, revealing that a strict discontinuity between velocity fields is not required for mixing enhancement, via streamline crossing, to occur. Optimal mixing was found to occur for the combination R = 0.2 D and R = 0.5 D , producing a 70 % increase in mixing, compared with standard single helical designs. The findings of this work point to the benefits of swirl disruption and suggest concatenation as an efficient means to determine optimal configurations of repeating geometries for future designs of vascular prostheses.
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Hatoum H, Maureira P, Dasi LP. A turbulence in vitro assessment of On-X and St Jude Medical prostheses. J Thorac Cardiovasc Surg 2019; 159:88-97. [PMID: 30905419 PMCID: PMC6703975 DOI: 10.1016/j.jtcvs.2019.02.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/17/2019] [Accepted: 02/09/2019] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The objective of this study was to investigate and compare the hemodynamic and turbulence characteristics upon implantation of St Jude Medical (SJM) (St Jude Medical, St Paul, Minn) and On-X (On-X Life Technologies, Kennesaw, Ga) bileaflet mechanical valves. Both valves are considered highly successful bileaflet mechanical valves characterized by good clinical outcomes despite their numerous design differences. Although thromboembolism remains the main disadvantage of bileaflet mechanical valves, On-X valves have been shown to need less anticoagulation therapy. METHODS Hemodynamic assessment of a 23-mm On-X bileaflet mechanical valve and a 23-mm bileaflet SJM valve implanted in an aortic root was performed under pulsatile physiologic conditions. Time-resolved and phase-locked particle-image-velocimetry images and high-speed imaging data were acquired. Pressure gradients, effective orifice areas, dimensionless area index, leaflet position tracking, velocity, and principal Reynolds shear stress were calculated. RESULTS Pressure gradient for the On-X valve was 4.15 ± 0.099 mm Hg versus 4.75 ± 0.048 mm Hg for SJM (P < .001). Effective orifice area for the On-X valve was 2.61 ± 0.045 cm2 versus 2.36 ± 0.022 cm2 for SJM (P < .001). Area index was higher with SJM (0.87 ± 0.008) than with On-X (0.73 ± 0.013) (P < .001). On-X showed fluctuating leaflet behavior during systole, whereas SJM leaflets were stable. At peak systole, the maximal velocity with On-X was 1.86 m/s versus 2.33 m/s with SJM. Reynolds shear stress was higher with On-X compared with SJM at peak systole (95 vs 72 Pa). Higher velocity fluctuation was noted with the On-X valve. CONCLUSIONS This study shows that despite the design differences that characterize the On-X valve, the hemodynamic and turbulence parameters were not necessarily improved compared with SJM.
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Affiliation(s)
- Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Pablo Maureira
- Department of Cardiovascular Surgery, CHU de Nancy, Nancy, France
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio.
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Mitral Valve Prosthesis Design Affects Hemodynamic Stasis and Shear In The Dilated Left Ventricle. Ann Biomed Eng 2019; 47:1265-1280. [DOI: 10.1007/s10439-019-02218-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/23/2019] [Indexed: 11/26/2022]
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Hatoum H, Dasi LP. Reduction of Pressure Gradient and Turbulence Using Vortex Generators in Prosthetic Heart Valves. Ann Biomed Eng 2019; 47:85-96. [PMID: 30209706 PMCID: PMC6408289 DOI: 10.1007/s10439-018-02128-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/10/2018] [Indexed: 11/30/2022]
Abstract
Blood damage and platelet activation are inherent problems with present day bi-leaflet mechanical heart valve designs. Passive flow control through different arrangements of vortex generators (VG) as means of improving pressure gradients and reducing turbulence are investigated. Rectangular VG arrays were mounted on the downstream surfaces of a 23 mm 3D printed mechanical valve. The effect of VGs on the resulting flow structures were assessed under pulsatile physiological flow conditions where high resolution particle image velocimetry measurement was performed. The co-rotating VGs showed lower Reynolds shear stresses and improved pressure gradients (PG) compared with the counter-rotating ones and the no-VG control one (that showed higher turbulence). RSS was found 38.13 ± 0.89, 12.95 ± 0.32, 15.75 ± 0.71, 24.54 ± 0.84 and 16.33 ± 0.58 Pa for the control, co-rotating VGs, 8 counter-rotating VGs, 4 far-spaced VGs and 4 closely-spaced VGs, respectively. PG of 10.45 ± 0.94 mmHg was obtained with co-rotating VGs and the difference was significant compared with the other configurations (control 14.88 ± 0.4 mmHg; 8 counter-rotating VGs 13.76 ± 0.51 mmHg; 4 far-spaced VGs 13.84 ± 0.09 mmHg; and 4 closely-spaced VGs 15.37 ± 0.16 mmHg). Co-rotating VGs for this application induce a more delayed flow separation and a more homogenized and streamlined transition of flow compared with the counter-rotating VGs. Passive flow control techniques deployed on BHMVs is potentially beneficial as significant control of flow at small length scales without inducing large-scale design modifications of the valve.
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Affiliation(s)
- Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, 473W 12th Ave., Columbus, OH, 43210, USA
| | - Lakshmi P Dasi
- Department of Biomedical Engineering, The Ohio State University, 473W 12th Ave., Columbus, OH, 43210, USA.
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Barakat M, Dvir D, Azadani AN. Fluid Dynamic Characterization of Transcatheter Aortic Valves Using Particle Image Velocimetry. Artif Organs 2018; 42:E357-E368. [DOI: 10.1111/aor.13290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/27/2018] [Accepted: 05/01/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Mohammed Barakat
- Department of Mechanical and Materials Engineering; University of Denver; Denver CO USA
| | - Danny Dvir
- Department of Medicine, Division of Cardiology; University of Washington; Seattle WA USA
| | - Ali N. Azadani
- Department of Mechanical and Materials Engineering; University of Denver; Denver CO USA
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Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study. FLUIDS 2018. [DOI: 10.3390/fluids3030056] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
(1) The study’s objective is to assess sinus hemodynamics differences between stenotic native bicuspid aortic valve (BAV) and native tricuspid aortic valve (TrAV) sinuses in order to assess sinus flow shear and vorticity dynamics in these common pathological states of the aortic valve. (2) Representative patient-specific aortic roots with BAV and TrAV were selected, segmented, and 3D printed. The flow dynamics within the sinus were assessed in-vitro using particle image velocimetry in a left heart simulator at physiological pressure and flow conditions. Hemodynamic data calculations, vortex tracking, shear stress probability density functions and sinus washout calculations based on Lagrangian particle tracking were performed. (3) (a) At peak systole, velocity and vorticity in BAV reach 0.67 ± 0.02 m/s and 374 ± 5 s−1 versus 0.49 ± 0.03 m/s and 293 ± 3 s−1 in TrAV; (b) Aortic sinus vortex is slower to form but conserved in BAV sinus; (c) BAV shear stresses exceed those of TrAV (1.05 Pa versus 0.8 Pa); (d) Complete TrAV washout was achieved after 1.5 cycles while it was not for BAV. 4) In conclusion, sinus hemodynamics dependence on the different native aortic valve types and sinus morphologies was clearly highlighted in this study.
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Abstract
Inertial microfluidics is a widely used technology which enables label-free manipulation of particles in microchannels. However, this technology has been limited to bioparticles larger than RBCs, due to the strong correlation between the inertial lift forces and the particle size. This paper presents a method to extend the capabilities of inertial microfluidics to smaller bioparticles, of which a plethora of clinically relevant types exist in the human body. Therefore, this method can be integrated with microfluidic devices for inertial manipulation of bioparticles that have defied all prior attempts, enabling a variety of applications in clinical diagnosis including cytometry of micron-scale bioparticles, isolation and characterization of pathogens and extracellular microvesicles, or phenotyping of cancer or stem cells at physiological shear stresses. Inertial microfluidics (i.e., migration and focusing of particles in finite Reynolds number microchannel flows) is a passive, precise, and high-throughput method for microparticle manipulation and sorting. Therefore, it has been utilized in numerous biomedical applications including phenotypic cell screening, blood fractionation, and rare-cell isolation. Nonetheless, the applications of this technology have been limited to larger bioparticles such as blood cells, circulating tumor cells, and stem cells, because smaller particles require drastically longer channels for inertial focusing, which increases the pressure requirement and the footprint of the device to the extent that the system becomes unfeasible. Inertial manipulation of smaller bioparticles such as fungi, bacteria, viruses, and other pathogens or blood components such as platelets and exosomes is of significant interest. Here, we show that using oscillatory microfluidics, inertial focusing in practically “infinite channels” can be achieved, allowing for focusing of micron-scale (i.e. hundreds of nanometers) particles. This method enables manipulation of particles at extremely low particle Reynolds number (Rep < 0.005) flows that are otherwise unattainable by steady-flow inertial microfluidics (which has been limited to Rep > ∼10−1). Using this technique, we demonstrated that synthetic particles as small as 500 nm and a submicron bacterium, Staphylococcus aureus, can be inertially focused. Furthermore, we characterized the physics of inertial microfluidics in this newly enabled particle size and Rep range using a Peclet-like dimensionless number (α). We experimentally observed that α >> 1 is required to overcome diffusion and be able to inertially manipulate particles.
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Stented valve dynamic behavior induced by polyester fiber leaflet material in transcatheter aortic valve devices. J Mech Behav Biomed Mater 2018; 86:232-239. [PMID: 29986298 DOI: 10.1016/j.jmbbm.2018.06.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/21/2018] [Accepted: 06/25/2018] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study aims at assessing the global dynamic behavior, elastic deformability, closing energy and turbulence of rigid versus deformable stented (RS vs DS) valve systems with deformable and rigid textile materials (DT vs RT) through studying the stent-valve interaction compared to a bioprosthetic material in transcatheter aortic valves (TAV). METHODS Three 19 mm stented textile TAV designs (RS-DT, RS-RT and DS-RT) with different stent and leaflet properties were tested and compared with a control bioprosthetic TAV (RS-DB) in a left heart simulator flow loop under physiological pressure and flow. Particle Image Velocimetry and high speed imaging were performed. Pressure gradients (PG), leakage fractions (LF), Pinwheeling indices (PI), closing energy (E) and Reynolds shear stresses (RSS) were calculated. RESULTS (a) PGs and LFs were 11.86 ± 0.51 mmHg, 11.70 ± 0.34%; 8.84 ± 0.40 mmHg, 29.80 ± 0.76%; 11.59 ± 0.12 mmHg, 14.23 ± 1.64%; and 7.05 ± 0.09 mmHg, 12.08 ± 0.45% % for RS-DB, RS-DT, RS-RT and DS-RT respectively. (b) PIs were 15.79 ± 2.34%, 4.36 ± 0.84%, 2.47 ± 0.51% and 2.03 ± 0.33% for RS-DB, RS-DT, RS-RT and DS-RT respectively. (c) E is lowest for DS-RT (0.0010 ± 0.0002 J) followed by RS-RT (0.0017 ± 0.0002 J), RS-DB (0.0023 ± 0.0004 J) and highest with RS-DT (0.0036 ± 0.0007 J). (d) At peak systole lowest RSS was obtained with RS-DT (87.82 ± 0.58 Pa) and highest with DS-RT (122.98 ± 1.87 Pa). CONCLUSION PGs, LFs, PIs and E were improved with DS-RT compared to other textile TAVs and RS-DB. Despite achieving more RSS than the rest of TAVs, DS-RT still falls within the same range of RSS produced by the other 2 valves and control exceeding the threshold for platelet activation.
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Hatoum H, Yousefi A, Lilly S, Maureira P, Crestanello J, Dasi LP. An in vitro evaluation of turbulence after transcatheter aortic valve implantation. J Thorac Cardiovasc Surg 2018; 156:1837-1848. [PMID: 29961588 DOI: 10.1016/j.jtcvs.2018.05.042] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 04/17/2018] [Accepted: 05/13/2018] [Indexed: 01/20/2023]
Abstract
BACKGROUND This study aimed at assessment of post-transcatheter aortic valve (TAV) replacement hemodynamics and turbulence when a same-size SAPIEN 3 (Edwards Lifesciences Corp, Irvine, Calif) and Medtronic Evolut (Minneapolis, Minn) were implanted in a rigid aortic root with physiological dimensions and in a representative root with calcific leaflets obtained from patient computed tomography scans. METHODS TAV hemodynamics were studied by placing a SAPIEN 3 26-mm and an Evolut 26-mm in rigid aortic roots and representative root with calcific leaflets under physiological conditions. Hemodynamics were assessed using high-fidelity particle image velocimetry and high-speed imaging. Transvalvular pressure gradients (PGs), pinwheeling indices, and Reynolds shear stress (RSS) were calculated. RESULTS (1) PGs obtained with the Evolut and the SAPIEN 3 were comparable among the different models (10.5 ± 0.15 mm Hg vs 7.76 ± 0.083 mm Hg in the rigid model along with 13.9 ± 0.19 mm Hg vs 5.0 ± 0.09 mm Hg in representative root with calcific leaflets obtained from patient computed tomography scans respectively); (2) more pinwheeling was found in the SAPIEN 3 than the Evolut (0.231 ± 0.057 vs 0.201 ± 0.05 in the representative root with calcific leaflets and 0.366 ± 0.067 vs 0.122 ± 0.045 in the rigid model); (3) higher rates of RSS were found in the Evolut (161.27 ± 3.45 vs 122.84 ± 1.76 Pa in representative root with calcific leaflets and 337.22 ± 7.05 vs 157.91 ± 1.80 Pa in rigid models). More lateral fluctuations were found in representative root with calcific leaflets. CONCLUSIONS (1) Comparable PGs were found among the TAVs in different models; (2) pinwheeling indices were found to be different between both TAVs; (3) turbulence patterns among both TAVs translated according to RSS were different. Rigid aortic models yield more conservative estimates of turbulence; (4) both TAVs exhibit peak maximal RSS that exceeds platelet activation 100 Pa threshold limit.
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Affiliation(s)
- Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Atieh Yousefi
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Scott Lilly
- Department of Surgery, The Ohio State University, Columbus, Ohio
| | - Pablo Maureira
- Department of Cardiovascular Surgery, CHU de Nancy, Nancy, France
| | - Juan Crestanello
- Department of Surgery, The Ohio State University, Columbus, Ohio
| | - Lakshmi P Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio; Department of Surgery, The Ohio State University, Columbus, Ohio.
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Mahr C, Chivukula V, McGah P, Prisco AR, Beckman JA, Mokadam NA, Aliseda A. Intermittent Aortic Valve Opening and Risk of Thrombosis in Ventricular Assist Device Patients. ASAIO J 2018; 63:425-432. [PMID: 28118265 PMCID: PMC5489364 DOI: 10.1097/mat.0000000000000512] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The current study evaluates quantitatively the impact that intermittent aortic valve (AV) opening has on the thrombogenicity in the aortic arch region for patients under left ventricular assist device (LVAD) therapy. The influence of flow through the AV, opening once every five cardiac cycles, on the flow patterns in the ascending aortic is measured in a patient-derived computed tomography image-based model, after LVAD implantation. The mechanical environment of flowing platelets is investigated, by statistical treatment of outliers in Lagrangian particle tracking, and thrombogenesis metrics (platelet residence times and activation state characterized by shear stress accumulation) are compared for the cases of closed AV versus intermittent AV opening. All hemodynamics metrics are improved by AV opening, even at a reduced frequency and flow rate. Residence times of platelets or microthrombi are reduced significantly by transvalvular flow, as are the shear stress history experienced and the shear stress magnitude and gradients on the aortic root endothelium. The findings of this device-neutral study support the multiple advantages of management that enables AV opening, providing a rationale for establishing this as a standard in long-term treatment and care for advanced heart failure patients.
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Affiliation(s)
- Claudius Mahr
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | | | - Patrick McGah
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Anthony R. Prisco
- Department of Internal Medicine, University of Minnesota, Minneapolis, MN, USA
| | | | - Nahush A. Mokadam
- Division of Cardiothoracic Surgery, University of Washington, Seattle, WA, USA
| | - Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
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Flow stagnation volume and abdominal aortic aneurysm growth: Insights from patient-specific computational flow dynamics of Lagrangian-coherent structures. Comput Biol Med 2018; 92:98-109. [DOI: 10.1016/j.compbiomed.2017.10.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 10/09/2017] [Accepted: 10/28/2017] [Indexed: 12/23/2022]
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39
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Aliseda A, Chivukula VK, McGah P, Prisco AR, Beckman JA, Garcia GJ, Mokadam NA, Mahr C. LVAD Outflow Graft Angle and Thrombosis Risk. ASAIO J 2017; 63:14-23. [PMID: 28033200 PMCID: PMC5201113 DOI: 10.1097/mat.0000000000000443] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
This study quantifies thrombogenic potential (TP) of a wide range of left ventricular assist device (LVAD) outflow graft anastomosis angles through state-of-the-art techniques: 3D imaged-based patient-specific models created via virtual surgery and unsteady computational fluid dynamics with Lagrangian particle tracking. This study aims at clarifying the influence of a single parameter (outflow graft angle) on the thrombogenesis associated with flow patterns in the aortic root after LVAD implantation. This is an important and poorly-understood aspect of LVAD therapy, because several studies have shown strong inter and intrapatient thrombogenic variability and current LVAD implantation strategies do not incorporate outflow graft angle optimization. Accurate platelet-level investigation, enabled by statistical treatment of outliers in Lagrangian particle tracking, demonstrates a strong influence of outflow graft anastomoses angle on thrombogenicity (platelet residence times and activation state characterized by shear stress accumulation) with significantly reduced TP for acutely-angled anastomosed outflow grafts. The methodology presented in this study provides a device-neutral platform for conducting comprehensive thrombogenicity evaluation of LVAD surgical configurations, empowering optimal patient-focused surgical strategies for long-term treatment and care for advanced heart failure patients.
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Affiliation(s)
- Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | | | - Patrick McGah
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Anthony R. Prisco
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Guilherme J.M. Garcia
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Nahush A Mokadam
- Division of Cardiothoracic Surgery, University of Washington, Seattle, WA, USA
| | - Claudius Mahr
- Division of Cardiology, University of Washington, Seattle, WA, USA
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40
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Ismail M, Kabinejadian F, Nguyen YN, Tay ELW, Leo HL. Design and Development of Novel Transcatheter Bicaval Valves in the Interventional Treatment of Tricuspid Regurgitation. Artif Organs 2017; 42:E13-E28. [PMID: 28891078 DOI: 10.1111/aor.12994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/30/2017] [Accepted: 06/14/2017] [Indexed: 11/28/2022]
Abstract
The concept of heterotopic implantation of transcatheter tricuspid valve is new and has shown promising results thus far. While the Reynolds shear stress values measured in the vicinity of this valve are relatively low, the values at some time points are higher than the threshold of platelet activation. Hence, in this study, we aim to reduce these values with an innovative stent design. It was shown that the Reynolds shear stress values measured were lower than those of valves made of generic stent design and the maximum Reynolds shear stress values in the vicinity of the valves was very low (∼10 dynes/cm2 ). The results also depicted the interesting flow phenomenon of this non-physiological treatment approach. Thus, this study has shown that bicaval valves could potentially be considered as a minimally invasive option to treat tricuspid regurgitation and valve design improvements could reduce the flow disturbances that were observed.
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Affiliation(s)
- Munirah Ismail
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Foad Kabinejadian
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Yen Ngoc Nguyen
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Edgar Lik Wui Tay
- Department of Cardiology, National University Heart Centre, Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Singapore
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41
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Mutlu BR, Smith KC, Edd JF, Nadar P, Dlamini M, Kapur R, Toner M. Non-equilibrium Inertial Separation Array for High-throughput, Large-volume Blood Fractionation. Sci Rep 2017; 7:9915. [PMID: 28855584 PMCID: PMC5577162 DOI: 10.1038/s41598-017-10295-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/07/2017] [Indexed: 11/11/2022] Open
Abstract
Microfluidic blood processing is used in a range of applications from cancer therapeutics to infectious disease diagnostics. As these applications are being translated to clinical use, processing larger volumes of blood in shorter timescales with high-reliability and robustness is becoming a pressing need. In this work, we report a scaled, label-free cell separation mechanism called non-equilibrium inertial separation array (NISA). The NISA mechanism consists of an array of islands that exert a passive inertial lift force on proximate cells, thus enabling gentler manipulation of the cells without the need of physical contact. As the cells follow their size-based, deterministic path to their equilibrium positions, a preset fraction of the flow is siphoned to separate the smaller cells from the main flow. The NISA device was used to fractionate 400 mL of whole blood in less than 3 hours, and produce an ultrapure buffy coat (96.6% white blood cell yield, 0.0059% red blood cell carryover) by processing whole blood at 3 mL/min, or ∼300 million cells/second. This device presents a feasible alternative for fractionating blood for transfusion, cellular therapy and blood-based diagnostics, and could significantly improve the sensitivity of rare cell isolation devices by increasing the processed whole blood volume.
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Affiliation(s)
- Baris R Mutlu
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, 02114, USA
| | - Kyle C Smith
- MicroMedicine Inc., Watertown, Massachusetts, 02472, USA
| | - Jon F Edd
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, 02114, USA.,Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts, 02114, USA
| | - Priyanka Nadar
- MicroMedicine Inc., Watertown, Massachusetts, 02472, USA
| | - Mcolisi Dlamini
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, 02114, USA
| | - Ravi Kapur
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, 02114, USA.,Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts, 02114, USA.,MicroMedicine Inc., Watertown, Massachusetts, 02472, USA
| | - Mehmet Toner
- BioMEMS Resource Center, Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, 02114, USA. .,Shriners Hospital for Children, Boston, Massachusetts, 02114, USA.
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42
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Affiliation(s)
- Lauren D.C. Casa
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332;,
| | - David N. Ku
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332;,
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Hedayat M, Asgharzadeh H, Borazjani I. Platelet activation of mechanical versus bioprosthetic heart valves during systole. J Biomech 2017; 56:111-116. [DOI: 10.1016/j.jbiomech.2017.03.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 11/16/2022]
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Impact of Using Conventional Inlet/Outlet Boundary Conditions on Haemodynamic Metrics in a Subject-Specific Rabbit Aorta. Proc Inst Mech Eng H 2017; 232:103-113. [DOI: 10.1177/0954411917699237] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Computational fluid dynamics is a tool capable of accurately measuring metrics currently used to predict the behaviour of cardiovascular diseases. This study quantifies the impact various commonly used inlet and outlet boundary conditions have on various shear rate–based haemodynamic metrics currently used for predicting the localisation of cardiovascular diseases. Simulations are conducted on an accurately represented rabbit aorta configuration and comparison has been made against available in vivo data. The boundary conditions studied include two different inlet profiles, three outlet boundary conditions, and steady-state versus pulsatile flow cases. Large variations were found in the results, particularly when using different outlet boundary conditions, and the discrepancies were evaluated both quantitatively and qualitatively. The results clearly highlight the importance of the type of boundary condition used when simulating complex cardiovascular models. By restricting the attention to the flow within the aorta and the intercostal branches, the results suggest that prescribing transient simulation and fully developed flow at the inlet are not required. Furthermore, assuming the widely accepted low wall shear stress theory of Caro, it was found that Murray’s law–based outlet boundary condition returns the most physiologically accurate results when compared to in vivo data.
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45
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A robust approach for exploring hemodynamics and thrombus growth associations in abdominal aortic aneurysms. Med Biol Eng Comput 2017; 55:1493-1506. [DOI: 10.1007/s11517-016-1610-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/24/2016] [Indexed: 10/20/2022]
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46
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Numerical Assessment of Novel Helical/Spiral Grafts with Improved Hemodynamics for Distal Graft Anastomoses. PLoS One 2016; 11:e0165892. [PMID: 27861485 PMCID: PMC5115668 DOI: 10.1371/journal.pone.0165892] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 10/19/2016] [Indexed: 11/19/2022] Open
Abstract
In the present work, numerical simulations were conducted for a typical end-to-side distal graft anastomosis to assess the effects of inducing secondary flow, which is believed to remove unfavourable flow environment. Simulations were carried out for four models, generated based on two main features of 'out-of-plane helicity' and 'spiral ridge' in the grafts as well as their combination. Following a qualitative comparison against in vitro data, various mean flow and hemodynamic parameters were compared and the results showed that helicity is significantly more effective in inducing swirling flow in comparison to a spiral ridge, while their combination could be even more effective. In addition, the induced swirling flow was generally found to be increasing the wall shear stress and reducing the flow stagnation and particle residence time within the anastomotic region and the host artery, which may be beneficial to the graft longevity and patency rates. Finally, a parametric study on the spiral ridge geometrical features was conducted, which showed that the ridge height and the number of spiral ridges have significant effects on inducing swirling flow, and revealed the potential of improving the efficiency of such designs.
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47
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Sheriff J, Tran PL, Hutchinson M, DeCook T, Slepian MJ, Bluestein D, Jesty J. The platelet hammer: In vitro platelet activation under repetitive hypershear. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:262-5. [PMID: 26736250 DOI: 10.1109/embc.2015.7318350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mechanical circulatory support (MCS) devices, such as ventricular assist devices and the total artificial heart, have emerged as a vital therapy for advanced and end-stage heart failure. However, MCS patients face life-long antiplatelet and anticoagulant therapy to minimize thrombotic complications resulting from the dynamic and supraphysiologic device-associated shear stress conditions, whose effect on platelet activation is poorly understood. We repeatedly exposed platelets to average shear stresses up to 1000 dyne/cm(2) for as short as 25 ms in the "platelet hammer," a syringe-capillary viscometer. Platelet activation state was measured using a modified prothrombinase assay and morphological changes analyzed using scanning electron microscopy. An increase in stress accumulation (SA), the product of shear stress and exposure time, led to an increase in the platelet activation state and post-high shear platelet activation rate, or sensitization. A significant increase in platelet activation state was observed beyond an SA of 1500 dyne-s/cm(2), with a marked increase in pseudopod length visible beyond an SA of 1000 dyne-s/cm(2). The platelet hammer may be used to study other shear-dependent pathologies and may ultimately enhance the safety and effectiveness of MCS devices and objective antithrombotic pharmacotherapy management.
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48
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Flow-Induced Damage to Blood Cells in Aortic Valve Stenosis. Ann Biomed Eng 2016; 44:2724-36. [PMID: 27048168 PMCID: PMC9924290 DOI: 10.1007/s10439-016-1577-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/23/2016] [Indexed: 12/11/2022]
Abstract
Valvular hemolysis and thrombosis are common complications associated with stenotic heart valves. This study aims to determine the extent to which hemodynamics induce such traumatic events. The viscous shear stress downstream of a severely calcified bioprosthetic valve was evaluated via in vitro 2D particle image velocimetry measurements. The blood cell membrane response to the measured stresses was then quantified using 3D immersed-boundary computational simulations. The shear stress level at the boundary layer of the jet flow formed downstream of the valve orifice was observed to reach a maximum of 1000-1700 dyn/cm(2), which was beyond the threshold values reported for platelet activation (100-1000 dyn/cm(2)) and within the range of thresholds reported for red blood cell (RBC) damage (1000-2000 dyn/cm(2)). Computational simulations demonstrated that the resultant tensions at the RBC membrane surface were unlikely to cause instant rupture, but likely to lead to membrane plastic failure. The resultant tensions at the platelet surface were also calculated and the potential damage was discussed. It was concluded that although shear-induced thrombotic trauma is very likely in stenotic heart valves, instant hemolysis is unlikely and the shear-induced damage to RBCs is mostly subhemolytic.
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49
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Horkay F, Martin P, Gupta NK, Satur C, Walker DR. Transient hypercoagulability in adult patients following open-heart surgery. Perfusion 2016. [DOI: 10.1177/026765919200700207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The technique of thrombelastography was used to assess whether the phenomenon of hypercoagulability (accelerated coagulation) occurred in adult patients (n = 20) undergoing consecutive open-heart surgical procedures. Standard haematological investigations (pre- and 2 hours postop) were also performed and comparisons made with thrombelastographic parameters. Thrombelastographic hypercoagulability was identified in 12/20 (60%) cases but this event was transient occurring immediately postprotamine administration, and normalizing at 2h postoperation. The standard postoperative haematological assessments routinely made 2h after operation failed to detect this phenomenon. Hypercoagulability following cardiac surgery in adult patients merits further evaluation in order that the clinical significance may be determined.
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Affiliation(s)
- F. Horkay
- Cardiothoracic Unit, Killingbeck Hospital, Leeds
| | - P. Martin
- Cardiothoracic Unit, Killingbeck Hospital, Leeds
| | - NK Gupta
- Cardiothoracic Unit, Killingbeck Hospital, Leeds
| | - Cmr Satur
- Cardiothoracic Unit, Killingbeck Hospital, Leeds
| | - DR Walker
- Cardiothoracic Unit, Killingbeck Hospital, Leeds
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50
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Raben JS, Hariharan P, Robinson R, Malinauskas R, Vlachos PP. Time-Resolved Particle Image Velocimetry Measurements with Wall Shear Stress and Uncertainty Quantification for the FDA Nozzle Model. Cardiovasc Eng Technol 2015; 7:7-22. [DOI: 10.1007/s13239-015-0251-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
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