1
|
Kreinin Y, Talmon Y, Levi M, Khoury M, Or I, Raad M, Bolotin G, Sznitman J, Korin N. A Fibrin-Thrombin Based In Vitro Perfusion System to Study Flow-Related Prosthetic Heart Valves Thrombosis. Ann Biomed Eng 2024; 52:1665-1677. [PMID: 38459196 PMCID: PMC11082030 DOI: 10.1007/s10439-024-03480-6] [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: 11/02/2023] [Accepted: 02/20/2024] [Indexed: 03/10/2024]
Abstract
Prosthetic heart valve (PHV) replacement has increased the survival rate and quality of life for heart valve-diseased patients. However, PHV thrombosis remains a critical problem associated with these procedures. To better understand the PHV flow-related thrombosis problem, appropriate experimental models need to be developed. In this study, we present an in vitro fibrin clot model that mimics clot accumulation in PHVs under relevant hydrodynamic conditions while allowing real-time imaging. We created 3D-printed mechanical aortic valve models that were inserted into a transparent glass aorta model and connected to a system that simulates human aortic flow pulse and pressures. Thrombin was gradually injected into a circulating fibrinogen solution to induce fibrin clot formation, and clot accumulation was quantified via image analysis. The results of valves positioned in a normal versus a tilted configuration showed that clot accumulation correlated with the local flow features and was mainly present in areas of low shear and high residence time, where recirculating flows are dominant, as supported by computational fluid dynamic simulations. Overall, our work suggests that the developed method may provide data on flow-related clot accumulation in PHVs and may contribute to exploring new approaches and valve designs to reduce valve thrombosis.
Collapse
Affiliation(s)
- Yevgeniy Kreinin
- Department of Biomedical Engineering, Technion-IIT, 3200003, Haifa, Israel
| | - Yahel Talmon
- Department of Biomedical Engineering, Technion-IIT, 3200003, Haifa, Israel
| | - Moran Levi
- Department of Biomedical Engineering, Technion-IIT, 3200003, Haifa, Israel
| | - Maria Khoury
- Department of Biomedical Engineering, Technion-IIT, 3200003, Haifa, Israel
| | - Itay Or
- Department of Cardiac Surgery, Rambam Health Care Campus, 3109601, Haifa, Israel
| | - Mahli Raad
- Department of Cardiac Surgery, Rambam Health Care Campus, 3109601, Haifa, Israel
| | - Gil Bolotin
- Department of Cardiac Surgery, Rambam Health Care Campus, 3109601, Haifa, Israel
- The Ruth Bruce Rappaport Faculty of Medicine, Technion-IIT, 3525433, Haifa, Israel
| | - Josué Sznitman
- Department of Biomedical Engineering, Technion-IIT, 3200003, Haifa, Israel
| | - Netanel Korin
- Department of Biomedical Engineering, Technion-IIT, 3200003, Haifa, Israel.
| |
Collapse
|
2
|
Gao X, Zhang T, Huang X, Huan X, Li Y. Impact of rise and fall phases of shear on platelet activation and aggregation using microfluidics. J Thromb Thrombolysis 2024; 57:576-586. [PMID: 38556576 DOI: 10.1007/s11239-024-02968-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/10/2024] [Indexed: 04/02/2024]
Abstract
Blood flow disorders are often the result of the non-physiological narrowing of blood arteries caused by atherosclerosis and thrombus. The blood then proceeds through rising-peak-decreasing phases as it passes through the narrow area. Although abnormally high shear is known to activate platelets, the shear process that platelets undergo in small arteries is complex. Thus, understanding how each shear phase affects platelet activation can be used to improve antiplatelet therapy and decrease the risk of side effects like bleeding. Blood samples were sheared (68.8 ms,5200 s-1) in vitro by the microfluidic technique, and platelet activation levels (P-selectin and integrin αIIbβ3) and von Willebrand factor (vWF) binding to platelets were analyzed by flow cytometry. Post-stenosis platelet aggregation was dynamically detected using microfluidic technology. We studied TXA2, P2Y12-ADP, and integrin αIIbβ3-fibrinogen receptor pathways by adding antiplatelet drugs, such as acetylsalicylic acid (ASA, an active ingredient of aspirin that inhibits platelet metabolism), ticagrelor (hinders platelet activation), and tirofiban (blocks integrin αIIbβ3 receptor) in vitro, respectively, to determine platelet activation function mediated by transient non-physiological high shear rates. We demonstrated that platelets can be activated under transient pathological high shear rates. The shear rise and fall phases influenced shear-induced platelet activation by regulating the binding of vWF to platelets. The degree of platelet activation and aggregation increased with multiple shear rise and fall phases. ASA did not inhibit shear-mediated platelet activation, but ticagrelor and tirofiban effectively inhibited shear-mediated platelet activation. Our data demonstrated that the shear rise and fall phases play an important role in shear-mediated platelet activation and promote platelet activation and aggregation in a vWF-dependent manner. Blocking integrin αIIbβ3 receptor and hindering P2Y12-ADP were beneficial to reducing shear-mediated platelet activation.
Collapse
Affiliation(s)
- Xuemei Gao
- Central Laboratory of Yong-Chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Tiancong Zhang
- Department of Laboratory, West China Hospital, Sichuan University, Sichuan, China
| | - Xiaojing Huang
- Central Laboratory of Yong-Chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Xuanrong Huan
- Department of Clinical Laboratory of Yong-Chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Yuan Li
- Central Laboratory of Yong-Chuan Hospital, Chongqing Medical University, Chongqing, China.
| |
Collapse
|
3
|
Steadman E, Steadman D, Rubenstein DA, Yin W. Platelet and endothelial cell responses under concurrent shear stress and tensile strain. Microvasc Res 2024; 151:104613. [PMID: 37793562 DOI: 10.1016/j.mvr.2023.104613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/13/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
Thrombosis can lead to significant mortality and morbidity. Both platelets and vascular endothelial cells play significant roles in thrombosis. Platelets' response to blood flow-induced shear stress can vary greatly depending on shear stress magnitude, pattern and shear exposure time. Endothelial cells are also sensitive to the biomechanical environment. Endothelial cell activation and dysfunction can occur under low oscillatory shear stress and low tensile strain. Platelet and endothelial cell interaction can also be affected by mechanical conditions. The goal of this study was to investigate how blood flow-induced shear stress, vascular wall tensile strain, platelet-endothelial cell stress history, and platelet-endothelial cell interaction affect platelet thrombogenicity. Platelets and human coronary artery endothelial cells were pretreated with physiological and pathological shear stress and/or tensile strain separately. The pretreated cells were then put together and exposed to pulsatile shear stress and cyclic tensile strain simultaneously in a shearing-stretching device. Following treatment, platelet thrombin generation rate, platelet and endothelial cell activation, and platelet adhesion to endothelial cells was measured. The results demonstrated that shear stress pretreatment of endothelial cells and platelets caused a significant increase in platelet thrombin generation rate, cell surface phosphatidylserine expression, and adhesion to endothelial cells. Shear stress pretreatment of platelets and endothelial cells attenuated endothelial cell ICAM-1 expression under stenosis conditions, as well as vWF expression under recirculation conditions. These results indicate that platelets are sensitized by prior shearing, while in comparison, the interaction with shear stress-pretreated platelets may reduce endothelial cell sensitivity to pathological shear stress and tensile strain.
Collapse
Affiliation(s)
- Elisabeth Steadman
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Danielle Steadman
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd., Stony Brook, NY 11794, USA
| | - David A Rubenstein
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Wei Yin
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd., Stony Brook, NY 11794, USA.
| |
Collapse
|
4
|
Gao X, Zhang T, Huang X, Huan X, Li Y. Evaluating the impact of transient shear stress on platelet activation, adhesion, and aggregation with microfluidic chip technique. Artif Organs 2024; 48:28-36. [PMID: 37792630 DOI: 10.1111/aor.14653] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/16/2023] [Accepted: 09/08/2023] [Indexed: 10/06/2023]
Abstract
BACKGROUND When nonphysiological stenosis occurs, the transient high shear stress formed in vessels increases the risk of thrombosis and is a potential factor for cardiovascular diseases. But the platelet adhesion and aggregation behavior at nonphysiological post-stenosis and its affecting factors are not fully understood yet. METHODS In this experiment, platelet aggregation on collagen and fibrinogen at different shear stresses and different hematocrits were observed by microfluidic technology. Platelet activation (P-selectin, glycoprotein IIb/IIIa) and monocyte-platelet aggregate (MPA) levels under different shear stresses were analyzed by flow cytometry. RESULTS On fibrinogen, platelets aggregate more at higher shear stress conditions. While on collagen, it becomes more difficult for platelets to form stable aggregation at higher shear stress conditions. If platelets adhere initially at low shear stress, stable platelet aggregation can be formed at subsequent high shear stress. Moreover, when the shear stress increases, platelet activity markers (P-selectin, glycoprotein IIb/IIIa and MPAs) increase significantly. Hematocrit affects the degree of platelet aggregation, and the influence of hematocrit is obvious at high shear stress. CONCLUSION Transient high shear stress (46 ms) can effectively activate platelets. Platelet aggregation behavior was different for coated fibrinogen and collagen protein. Stable platelet adhesion at post-stenosis is more dependent on fibrinogen and platelet aggregation is stable on both fibrinogen and collagen. Hematocrit can significantly affect the formation of platelet aggregation.
Collapse
Affiliation(s)
- Xuemei Gao
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Tiancong Zhang
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Xiaojing Huang
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Xuanrong Huan
- Department of Clinical Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| | - Yuan Li
- Central Laboratory of Yong-chuan Hospital, Chongqing Medical University, Chongqing, China
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Bass DI, Marsh LMM, Fillingham P, Lim D, Chivukula VK, Kim LJ, Aliseda A, Levitt MR. Modeling the Mechanical Microenvironment of Coiled Cerebral Aneurysms. J Biomech Eng 2023; 145:041005. [PMID: 36193892 PMCID: PMC9791668 DOI: 10.1115/1.4055857] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 09/09/2022] [Indexed: 12/30/2022]
Abstract
Successful occlusion of cerebral aneurysms using coil embolization is contingent upon stable thrombus formation, and the quality of the thrombus depends upon the biomechanical environment. The goal of this study was to investigate how coil embolization alters the mechanical micro-environment within the aneurysm dome. Inertialess particles were injected in three-dimensional, computational simulations of flow inside patient aneurysms using patient-specific boundary conditions. Coil embolization was simulated as a homogenous porous medium of known permeability and inertial constant. Lagrangian particle tracking was used to calculate the residence time and shear stress history for particles in the flow before and after treatment. The percentage of particles entering the aneurysm dome correlated with the neck surface area before and after treatment (pretreatment: R2 = 0.831, P < 0.001; post-treatment: R2 = 0.638, P < 0.001). There was an inverse relationship between the change in particles entering the dome and coil packing density (R2 = 0.600, P < 0.001). Following treatment, the particles with the longest residence times tended to remain within the dome even longer while accumulating lower shear stress. A significant correlation was observed between the treatment effect on residence time and the ratio of the neck surface area to porosity (R2 = 0.390, P = 0.007). The results of this study suggest that coil embolization triggers clot formation within the aneurysm dome via a low shear stress-mediated pathway. This hypothesis links independently observed findings from several benchtop and clinical studies, furthering our understanding of this treatment strategy.
Collapse
Affiliation(s)
- David I. Bass
- Department of Neurological Surgery, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104
| | - Laurel M. M. Marsh
- Department of Mechanical Engineering, University of Washington, 3900 East Stevens Way NE, Box 352600, Seattle, WA 98195
| | - Patrick Fillingham
- Department of Neurological Surgery, Stroke & Applied Neuroscience Center, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104
| | - Do Lim
- Department of Neurological Surgery, Stroke & Applied Neuroscience Center, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104
| | - V. Keshav Chivukula
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150 West University Building, Melbourne, FL 32901
| | - Louis J. Kim
- Department of Neurological Surgery, Stroke & Applied Neuroscience Center, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104; Department of Radiology, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104
| | - Alberto Aliseda
- Department of Mechanical Engineering, Stroke & Applied Neuroscience Center, University of Washington, 3900 East Stevens Way NE, Box 352600, Seattle, WA 98195; Department of Neurological Surgery, Stroke & Applied Neuroscience Center, University of Washington, 3900 East Stevens Way NE, Box 352600, Seattle, WA 98195
| | - Michael R. Levitt
- Department of Neurological Surgery, Stroke & Applied Neuroscience Center, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104; Department of Radiology, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104; Department of Mechanical Engineering, University of Washington, 325 9th Avenue, Box 359924, Seattle, WA 98104
| |
Collapse
|
7
|
Flow residence time in intracranial aneurysms evaluated by in vitro 4D flow MRI. J Biomech 2022; 141:111211. [DOI: 10.1016/j.jbiomech.2022.111211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 05/15/2022] [Accepted: 06/24/2022] [Indexed: 11/15/2022]
|
8
|
Görner S, Heim C, Weigmann B, von Silva-Tarouca B, Kuckhahn A, Ramsperger-Gleixner M, Zimmermann R, Weyand M, Ensminger SM. Direct Impact of Human Platelets on the Development of Transplant Arteriosclerosis. Transplantation 2022; 106:1180-1192. [PMID: 34468430 DOI: 10.1097/tp.0000000000003935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Platelets play an important role in the pathogenesis of inflammatory and proliferative vascular changes. The aim of this study was to investigate whether human platelets are able to induce transplant arteriosclerosis in a humanized C57/Bl6-Rag2-/-γc-/- mouse xenograft model. METHODS Nonactivated and in vitro-activated human platelets were analyzed and phenotyped for surface markers by flow cytometry. Side branches of human mammary arteries were implanted into the infrarenal aorta of recipients, followed by daily application of human platelets and histological analyzed on day 30 after transplantation. RESULTS Human platelets collected by apheresis had low levels of platelet activation markers. However, after in vitro activation, expression was markedly increased. Sixty minutes after injection in recipient mice, nonactivated human platelets become significantly activated. Increased adhesion of platelets to the vascular endothelium was detected by in vivo fluorescence microscopy. After intravenous injection of nonactivated or activated platelets, human xenografts showed pronounced intimal proliferation. Immunohistological analysis showed that the group treated with activated human platelets exhibited significantly increased intragraft protein expression of intracellular adhesion molecule-1 and platelet-derived growth factor receptor beta and smooth muscle cell migration into the neointima. CONCLUSIONS These data demonstrate that an isolated daily application of both in vivo- and in vitro-activated human platelets results in the development of transplant arteriosclerosis in a humanized mouse transplantation model.
Collapse
Affiliation(s)
- Susann Görner
- Department of Cardiac Surgery, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
| | - Christian Heim
- Department of Cardiac Surgery, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
| | - Benno Weigmann
- Department of Medicine 1, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
| | | | - Annika Kuckhahn
- Department of Cardiac Surgery, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
| | | | - Robert Zimmermann
- Department of Transfusion Medicine, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
| | - Michael Weyand
- Department of Cardiac Surgery, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
| | - Stephan M Ensminger
- Department of Cardiac Surgery, Friedrich-Alexander University, Erlangen-Nürnberg, Germany
- Present address: Department of Cardiac and Thoracic Vascular Surgery, University Heart Center Lübeck, University Hospital Schleswig Holstein, Lübeck, Germany
| |
Collapse
|
9
|
Mezali F, Benmamar S, Naima K, Ameur H, Rafik O. Evaluation of stent effect and thrombosis generation with different blood rheology on an intracranial aneurysm by the Lattice Boltzmann method. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 219:106757. [PMID: 35338884 DOI: 10.1016/j.cmpb.2022.106757] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/07/2022] [Accepted: 03/12/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Treatment of intracranial aneurysms with flow-diverting stents prevents rupture by reducing blood flow and creating thrombosis within the aneurysm. This paper aims to assess the hemodynamic effect of placing stents with different struts (0, 3, 5, 7 struts) on intracranial aneurysms and to propose a simple prediction model of thrombosis zone without any further computational cost. METHOD Lattice Boltzmann method with different rheological models (Newtonian, Carreau-Yasuda, KL) of blood are used to study the hemodynamic effect of flow-diverting stents in the aneurysm. Pulsatile flow boundary conditions were applied in the inlet of the artery. The average Reynolds number was resulting Re = 111. The Lagrangian tracking of the particle was developed to assess the intra-aneurysmal blood stagnation. To predict the probable thrombose zone induced by flow-diverting stents, the shear rate threshold is utilized to determine the nodes of fluid to clot. RESULTS The results show that the flow patterns into the aneurysmal sac develop a vortex, decreasing after stent placement until disappearance for the stent with seven struts (porosity 71.4%). Velocity, shear rate, shear stress, trajectory, path length, and occlusion rate are compared before and after stent placement. These parameters decrease inversely with the porosity of the stent. The three models yield a closes result of the (velocity, shear rate, occlusion rate). Tracking the fluid-particle trajectory shows that the length of the particle paths decreases with the number of struts causing fluid to slow down and increase, consequently, the residence time into the sac. CONCLUSION The flow-diverting stents placement cause the reduction of dynamic flow within aneurysm. The reduction effect is almost the same below five struts (80% of porosity). The results show that, if our objective is restricted to estimating the hemodynamic effect, measured by (velocity, shear rate, occlusion rate), the differences between rheological behavior models are, practically, not significant, and the models can be used indifferently.
Collapse
Affiliation(s)
- Farouk Mezali
- Water Sciences Research laboratory: LRS-Eau, National Polytechnic School, El harrach, Algiers; Hydraulics department, Faculty of Technology-BP 166 M'sila 28000 Algeria.
| | - Saida Benmamar
- Water Sciences Research laboratory: LRS-Eau, National Polytechnic School, El harrach, Algiers.
| | - Khatir Naima
- Department of Technology, University Centre of Naama (Ctr Univ Naama), P.O. Box 66, Naama 45000, Algeria.
| | - Houari Ameur
- Department of Technology, University Centre of Naama (Ctr Univ Naama), P.O. Box 66, Naama 45000, Algeria.
| | - Ouared Rafik
- Water Sciences Research laboratory: LRS-Eau, National Polytechnic School, El harrach, Algiers
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Consolo F, Della Valle P, Saracino M, Bonora M, Donadoni G, Ciceri F, Tresoldi M, D'Angelo A, Landoni G, Zangrillo A. Platelet activation state in early stages of Covid-19. Minerva Anestesiol 2022; 88:472-478. [PMID: 35315619 DOI: 10.23736/s0375-9393.22.16054-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Platelet activation at the early stage of COVID-19 is poorly described. The need for antiplatelet therapy in patients with COVID-19 remains controversial. We characterized the platelet activation profile in hospitalized patients at the early stage of COVID-19 using the modified prothrombinase Platelet Activation State (PAS) assay. METHODS Sixteen patients admitted to the emergency department of the IRCCS San Raffaele Scientific Institute (Milano, Italy) between February 8 and April 2021 were enrolled. All patients presented with respiratory symptoms and tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Platelet activation was measured via the PAS assay within 24 hours from patients' hospital admission. Data were compared with those measured in n=24 healthy subjects (controls). RESULTS Platelet activation was significantly higher in COVID-19 patients with respect to controls (PAS = 0.63 [0.58-0.98]% vs. 0.46 [0.40-0.65]%, respectively; p=0.03). Of note, highest PAS values were measured in the two patients with the worst clinical outcome, i.e., death because of respiratory failure (PAS = 2.09% and 1.20%, respectively). No differences in standard coagulation parameters were noted between these two patients and those who were later discharged home. CONCLUSIONS This study provides evidences of significant platelet activation state at the early stage of COVID-19 and suggests that the patient-specific platelet activation profile is a reliable clinical marker to stratify COVID-19 patients at high risk of poor clinical outcome who might potentially benefit from antiplatelet therapy.
Collapse
Affiliation(s)
- Filippo Consolo
- Università Vita Salute San Raffaele, Milano, Italy - .,Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milano, Italy -
| | - Patrizia Della Valle
- Coagulation Service and Thrombosis Research Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Marco Saracino
- Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Marta Bonora
- Università Vita Salute San Raffaele, Milano, Italy
| | - Giovanni Donadoni
- Emergency Department, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Fabio Ciceri
- Università Vita Salute San Raffaele, Milano, Italy.,Hematology and Bone Marrow Transplantation Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Moreno Tresoldi
- General Medicine and Advanced Care Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Armando D'Angelo
- Coagulation Service and Thrombosis Research Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Giovanni Landoni
- Università Vita Salute San Raffaele, Milano, Italy.,Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Alberto Zangrillo
- Università Vita Salute San Raffaele, Milano, Italy.,Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milano, Italy
| |
Collapse
|
12
|
Siewnicka A, Fajdek B, Janiszowski K. Extreme membrane position detection and pump output estimation in pulsatile VADs. Biomed Signal Process Control 2022. [DOI: 10.1016/j.bspc.2021.103409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
13
|
Sweedo A, Wise LM, Roka-Moiia Y, Arce FT, Saavedra SS, Sheriff J, Bluestein D, Slepian MJ, Purdy JG. Shear-Mediated Platelet Activation is Accompanied by Unique Alterations in Platelet Release of Lipids. Cell Mol Bioeng 2021; 14:597-612. [PMID: 34900013 PMCID: PMC8630256 DOI: 10.1007/s12195-021-00692-x] [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: 01/21/2021] [Accepted: 07/16/2021] [Indexed: 10/20/2022] Open
Abstract
INTRODUCTION Platelet activation by mechanical means such as shear stress exposure, is a vital driver of thrombotic risk in implantable blood-contacting devices used in the treatment of heart failure. Lipids are essential in platelets activation and have been studied following biochemical activation. However, little is known regarding lipid alterations occurring with mechanical shear-mediated platelet activation. METHODS Here, we determined if shear-activation of platelets induced lipidome changes that differ from those associated with biochemically-mediated platelet activation. We performed high-resolution lipidomic analysis on purified platelets from four healthy human donors. For each donor, we compared the lipidome of platelets that were non-activated or activated by shear, ADP, or thrombin treatment. RESULTS We found that shear activation altered cell-associated lipids and led to the release of lipids into the extracellular environment. Shear-activated platelets released 21 phospholipids and sphingomyelins at levels statistically higher than platelets activated by biochemical stimulation. CONCLUSIONS We conclude that shear-mediated activation of platelets alters the basal platelet lipidome. Further, these alterations differ and are unique in comparison to the lipidome of biochemically activated platelets. Many of the released phospholipids contained an arachidonic acid tail or were phosphatidylserine lipids, which have known procoagulant properties. Our findings suggest that lipids released by shear-activated platelets may contribute to altered thrombosis in patients with implanted cardiovascular therapeutic devices. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s12195-021-00692-x.
Collapse
Affiliation(s)
- Alice Sweedo
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ USA
| | - Lisa M. Wise
- Department of Immunobiology, University of Arizona, 1656 E. Mabel Street, PO Box 245221, Tucson, AZ 85724 USA
- BIO5 Institute, University of Arizona, Tucson, AZ USA
| | - Yana Roka-Moiia
- Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ USA
| | - Fernando Teran Arce
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ USA
- Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ USA
| | - S. Scott Saavedra
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ USA
- BIO5 Institute, University of Arizona, Tucson, AZ USA
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ USA
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY USA
| | - Marvin J. Slepian
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ USA
- BIO5 Institute, University of Arizona, Tucson, AZ USA
- Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ USA
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY USA
- Department of Material Sciences and Engineering, University of Arizona, Tucson, AZ USA
| | - John G. Purdy
- Department of Immunobiology, University of Arizona, 1656 E. Mabel Street, PO Box 245221, Tucson, AZ 85724 USA
- BIO5 Institute, University of Arizona, Tucson, AZ USA
| |
Collapse
|
14
|
Siegel PM, Hentschel D, Bojti I, Wengenmayer T, Helbing T, Moser M, Duerschmied D, Trummer G, Bode C, Diehl P. Annexin V positive microvesicles are elevated and correlate with flow rate in patients receiving veno-arterial extracorporeal membrane oxygenation. Interact Cardiovasc Thorac Surg 2021; 31:884-891. [PMID: 33164057 DOI: 10.1093/icvts/ivaa198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 07/21/2020] [Accepted: 08/16/2020] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used in critically ill patients requiring haemodynamic support. Microvesicles (MV) are released by activated blood cells acting as mediators of intercellular communication. We aimed to determine MV count and composition over time in patients with VA-ECMO and explore what drives MV formation. METHODS VA-ECMO patients and healthy controls were recruited prospectively, and blood was taken at different time points (day 0, 1, 3 after ECMO placement and after explantation) for MV analysis. RESULTS Annexin V positive MV were increased in patients (n = 14, mean age = 61.4 ± 9.0 years, 11 males, 3 females) compared to healthy controls (n = 6, Annexin V positive MV count per millilitre day 1 versus healthy controls: 2.3 × 106 vs 1.3 × 105, P < 0.001). Furthermore, patients had higher proportions of endothelial and leukocyte MV [leukocyte MV day 1 versus healthy controls (%): 32.8 vs 17.5, P = 0.001; endothelial MV day 1 versus healthy controls (%): 10.5 vs 5.5, P = 0.01]. Annexin V positive and leucocyte MV correlated with the flow rate (r = 0.46, P = 0.01). CONCLUSIONS Patients on VA-ECMO have increased levels of circulating MV and a changed MV composition. Our data support the hypothesis that MV release may be driven by higher flow rate and cellular activation in the extracorporeal circuit leading to poor outcomes in these patients. CLINICAL TRIAL REGISTRATION NUMBER German Clinical Trials Register-ID: DRKS00011106.
Collapse
Affiliation(s)
- Patrick M Siegel
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Dominik Hentschel
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - István Bojti
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Tobias Wengenmayer
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Thomas Helbing
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Martin Moser
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Daniel Duerschmied
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Georg Trummer
- Department of Cardiovascular Surgery, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Christoph Bode
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Philipp Diehl
- Department of Cardiology and Angiology I, Heart Center Freiburg University, Medical Faculty, University of Freiburg, Freiburg, Germany
| |
Collapse
|
15
|
Lemétayer J, Broman LM, Prahl Wittberg L. Flow Dynamics and Mixing in Extracorporeal Support: A Study of the Return Cannula. Front Bioeng Biotechnol 2021; 9:630568. [PMID: 33644022 PMCID: PMC7902508 DOI: 10.3389/fbioe.2021.630568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/04/2021] [Indexed: 11/13/2022] Open
Abstract
Cannulation strategies in medical treatment such as in extracorporeal life support along with the associated cannula position, orientation and design, affects the mixing and the mechanical shear stress appearing in the flow field. This in turn influences platelet activation state and blood cell destruction. In this study, a co-flowing confined jet similar to a return cannula flow configuration found in extracorporeal membrane oxygenation was investigated experimentally. Cannula diameters, flow rate ratios between the jet and the co-flow and cannula position were studied using Particle Image Velocimetry and Planar Laser Induced Fluorescence. The jet was turbulent for all but two cases, in which a transitional regime was observed. The mixing, governed by flow entrainment, shear layer induced vortices and a backflow along the vessel wall, was found to require 9–12 cannula diameters to reach a fully homogeneous mixture. This can be compared to the 22–30 cannula diameters needed to obtain a fully developed flow. Although not significantly affecting mixing characteristics, cannula position altered the development of the flow structures, and hence the shear stress characteristics.
Collapse
Affiliation(s)
- Julien Lemétayer
- FLOW & BioMEx, Department of Engineering Mechanics, Royal Institute of Technology (KTH), Stockholm, Sweden
| | - L Mikael Broman
- ECMO Centre Karolinska, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Lisa Prahl Wittberg
- FLOW & BioMEx, Department of Engineering Mechanics, Royal Institute of Technology (KTH), Stockholm, Sweden
| |
Collapse
|
16
|
Koh LB, Zuo K, Kumar GP, Ding X, Leo HL, Cui F, Charles CJ, Yang YY, Yim EKF, Ho P. Optimization of a Novel Preferential Covered Stent through Bench Experiments and in Vitro Platelet Activation Studies. ACS Biomater Sci Eng 2019; 5:6216-6230. [PMID: 33405529 DOI: 10.1021/acsbiomaterials.9b00763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bare metal stenting (BMS) does not adequately address the atheroembolic characteristic of carotid artery stenosis. While simple covered stents (CS) may prevent dislodged fragments of the atherosclerotic plaque from entering the blood stream, they also block blood flow into the major branches of the artery alongside the lesion, which is not desirable. Preferential covered stents (PCS) behave as a covered stent in a tubular part of a vessel but maintain side-branch flow over the bifurcation region by means of slits in the membrane. Stent design, membrane material, and slits configuration are the three main components contributing to stent performance. Optimization of PCS designs was conducted and tested. METHODS A newly designed BMS was developed and compared to a commercially available peripheral stent. Two materials (expanded poly(tetrafluoroethylene)) and silicone polyurethane co-polymers (Elast-eon E2A) were used as stent coverings with slits applied using various cutting methods to form the PCS. These PCS samples were tested for physical resilience, flexibility, ability to preserve side-branch flow, slit edge roughness, and platelet activation. RESULTS Fabrication of E2A-coated stents required pretreatment of the stent with poly(ethylene glycol) to achieve firm attachment. The newly designed BMS with nine crowns design and larger cell size showed higher flexibility than commercially available stents. A combination of a larger stent cell size, E2A membrane coating, and three slits per stent cell unit configuration resulted in preserved side-branch flow similar to physiological conditions in the flow experiment. Slit edge roughness changed with different cutting methods and laser machine cutting parameters. In vitro studies showed platelet activation was minimal with lower slit edge roughness samples. CONCLUSION An optimized PCS prototype was developed consisting of a newly designed stent, E2A membrane, and a three-slit pattern created by specific femtosecond laser cutting.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Evelyn K F Yim
- Department of Chemical Engineering, University of Waterloo, Ontario, Canada
| | - Pei Ho
- Department of Cardiac, Thoracic & Vascular Surgery, National University Health System, Singapore
| |
Collapse
|
17
|
Braune S, Latour RA, Reinthaler M, Landmesser U, Lendlein A, Jung F. In Vitro Thrombogenicity Testing of Biomaterials. Adv Healthc Mater 2019; 8:e1900527. [PMID: 31612646 DOI: 10.1002/adhm.201900527] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 08/15/2019] [Indexed: 12/29/2022]
Abstract
The short- and long-term thrombogenicity of implant materials is still unpredictable, which is a significant challenge for the treatment of cardiovascular diseases. A knowledge-based approach for implementing biofunctions in materials requires a detailed understanding of the medical device in the biological system. In particular, the interplay between material and blood components/cells as well as standardized and commonly acknowledged in vitro test methods allowing a reproducible categorization of the material thrombogenicity requires further attention. Here, the status of in vitro thrombogenicity testing methods for biomaterials is reviewed, particularly taking in view the preparation of test materials and references, the selection and characterization of donors and blood samples, the prerequisites for reproducible approaches and applied test systems. Recent joint approaches in finding common standards for a reproducible testing are summarized and perspectives for a more disease oriented in vitro thrombogenicity testing are discussed.
Collapse
Affiliation(s)
- Steffen Braune
- Institute of Biomaterial Science and Berlin‐Brandenburg Centre for Regenerative Therapies (BCRT)Helmholtz‐Zentrum Geesthacht Kantstrasse 55 14513 Teltow Germany
| | - Robert A. Latour
- Rhodes Engineering Research CenterDepartment of BioengineeringClemson University Clemson SC 29634 USA
| | - Markus Reinthaler
- Institute of Biomaterial Science and Berlin‐Brandenburg Centre for Regenerative Therapies (BCRT)Helmholtz‐Zentrum Geesthacht Kantstrasse 55 14513 Teltow Germany
- Department for CardiologyCharité UniversitätsmedizinCampus Benjamin Franklin Hindenburgdamm 30 12203 Berlin Germany
| | - Ulf Landmesser
- Department for CardiologyCharité UniversitätsmedizinCampus Benjamin Franklin Hindenburgdamm 30 12203 Berlin Germany
| | - Andreas Lendlein
- Institute of Biomaterial Science and Berlin‐Brandenburg Centre for Regenerative Therapies (BCRT)Helmholtz‐Zentrum Geesthacht Kantstrasse 55 14513 Teltow Germany
- Institute of ChemistryUniversity of Potsdam Karl‐Liebknecht‐Strasse 24‐25 14476 Potsdam Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine”Helmholtz‐Zentrum Geesthacht Kantstrasse 55 14513 Teltow Germany
| | - Friedrich Jung
- Institute of Biomaterial Science and Berlin‐Brandenburg Centre for Regenerative Therapies (BCRT)Helmholtz‐Zentrum Geesthacht Kantstrasse 55 14513 Teltow Germany
- Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine”Helmholtz‐Zentrum Geesthacht Kantstrasse 55 14513 Teltow Germany
| |
Collapse
|
18
|
Movafaghi S, Wang W, Bark DL, Dasi LP, Popat KC, Kota AK. Hemocompatibility of Super-Repellent surfaces: Current and Future. MATERIALS HORIZONS 2019; 6:1596-1610. [PMID: 31903188 PMCID: PMC6941870 DOI: 10.1039/c9mh00051h] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Virtually all blood-contacting medical implants and devices initiate immunological events in the form of thrombosis and inflammation. Typically, patients receiving such implants are also given large doses of anticoagulants, which pose a high risk and a high cost to the patient. Thus, the design and development of surfaces with improved hemocompatibility and reduced dependence on anticoagulation treatments is paramount for the success of blood-contacting medical implants and devices. In the past decade, the hemocompatibility of super-repellent surfaces (i.e., surfaces that are extremely repellent to liquids) has been extensively investigated because such surfaces greatly reduce the blood-material contact area, which in turn reduces the area available for protein adsorption and blood cell or platelet adhesion, thereby offering the potential for improved hemocompatibility. In this review, we critically examine the progress made in characterizing the hemocompatibility of super-repellent surfaces, identify the unresolved challenges and highlight the opportunities for future research on developing medical implants and devices with super-repellent surfaces.
Collapse
Affiliation(s)
- Sanli Movafaghi
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Wei Wang
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - David L Bark
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Lakshmi P Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Ketul C Popat
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
| | - Arun K Kota
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA
- Department of Chemical & Biological Engineering, Colorado State University, Fort Collins, CO 80523, USA
| |
Collapse
|
19
|
Marsh LMM, Barbour MC, Chivukula VK, Chassagne F, Kelly CM, Levy SH, Kim LJ, Levitt MR, Aliseda A. Platelet Dynamics and Hemodynamics of Cerebral Aneurysms Treated with Flow-Diverting Stents. Ann Biomed Eng 2019; 48:490-501. [PMID: 31549329 DOI: 10.1007/s10439-019-02368-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023]
Abstract
Flow-diverting stents (FDS) are used to treat cerebral aneurysms. They promote the formation of a stable thrombus within the aneurysmal sac and, if successful, isolate the aneurysmal dome from mechanical stresses to prevent rupture. Platelet activation, a mechanism necessary for thrombus formation, is known to respond to biomechanical stimuli, particularly to the platelets' residence time and shear stress exposure. Currently, there is no reliable method for predicting FDS treatment outcomes, either a priori or after the procedure. Eulerian computational fluid dynamic (CFD) studies of aneurysmal flow have searched for predictors of endovascular treatment outcome; however, the hemodynamics of thrombus formation cannot be fully understood without considering the platelets' trajectories and their mechanics-triggered activation. Lagrangian analysis of the fluid mechanics in the aneurysmal vasculature provides novel metrics by tracking the platelets' residence time (RT) and shear history (SH). Eulerian and Lagrangian parameters are compared for 19 patient-specific cases, both pre- and post-treatment, to assess the degree of change caused by the FDS and subsequent treatment efficacy.
Collapse
Affiliation(s)
- Laurel M M Marsh
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Michael C Barbour
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Venkat Keshav Chivukula
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Fanette Chassagne
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Cory M Kelly
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA
| | - Samuel H Levy
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA
| | - Louis J Kim
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA.,Radiology, University of Washington, Seattle, WA, USA
| | - Michael R Levitt
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA.,Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA.,Radiology, University of Washington, Seattle, WA, USA
| | - Alberto Aliseda
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA. .,Neurological Surgery, University of Washington, Seattle, WA, USA. .,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA.
| |
Collapse
|
20
|
Device Thrombogenicity Emulation: An In Silico Predictor of In Vitro and In Vivo Ventricular Assist Device Thrombogenicity. Sci Rep 2019; 9:2946. [PMID: 30814674 PMCID: PMC6393420 DOI: 10.1038/s41598-019-39897-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 02/04/2019] [Indexed: 12/02/2022] Open
Abstract
Ventricular assist devices (VAD), a mainstay of therapy for advanced and end-stage heart failure, remain plagued by device thrombogenicity. Combining advanced in silico and in vitro methods, Device Thrombogenicity Emulation (DTE) is a device design approach for enhancing VAD thromboresistance. Here we tested DTE efficacy in experimental VAD designs. DTE incorporates iterative design modifications with advanced CFD to compute the propensity of large populations of platelets to activate by flow-induced stresses (statistically representing the VAD ‘Thrombogenic Footprint’). The DTE approach was applied to a VAD (MINDTE) design with a favorable thromboresistance profile and compared against a design (MAXDTE) that generated an intentionally poor thromboresistance profile. DTE predictions were confirmed by testing physical prototypes in vitro by measuring VAD thrombogenicity using the modified prothrombinase assay. Chronic in vivo studies in VAD implanted calves, revealed MINDTE calf surviving well with low platelet activation, whereas the MAXDTE animal sustained thromboembolic strokes. DTE predictions were confirmed, correlating with in vitro and in vivo thrombogenicity, supporting utility in guiding device development, potentially reducing the need for animal studies.
Collapse
|
21
|
Ngo AT, Sheriff J, Rocheleau AD, Bucher M, Jones KR, Sepp ALI, Malone LE, Zigomalas A, Maloyan A, Bahou WF, Bluestein D, McCarty OJT, Haley KM. Assessment of neonatal, cord, and adult platelet granule trafficking and secretion. Platelets 2019; 31:68-78. [PMID: 30810440 PMCID: PMC6711836 DOI: 10.1080/09537104.2019.1573314] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/01/2019] [Accepted: 01/16/2019] [Indexed: 10/27/2022]
Abstract
Despite the transient hyporeactivity of neonatal platelets, full-term neonates do not display a bleeding tendency, suggesting potential compensatory mechanisms which allow for balanced and efficient neonatal hemostasis. This study aimed to utilize small-volume, whole blood platelet functional assays to assess the neonatal platelet response downstream of the hemostatic platelet agonists thrombin and adenosine diphosphate (ADP). Thrombin activates platelets via the protease-activated receptors (PARs) 1 and 4, whereas ADP signals via the receptors P2Y1 and P2Y12 as a positive feedback mediator of platelet activation. We observed that neonatal and cord blood-derived platelets exhibited diminished PAR1-mediated granule secretion and integrin activation relative to adult platelets, correlating to reduced PAR1 expression by neonatal platelets. PAR4-mediated granule secretion was blunted in neonatal platelets, correlating to lower PAR4 expression as compared to adult platelets, while PAR4 mediated GPIIb/IIIa activation was similar between neonatal and adult platelets. Under high shear stress, cord blood-derived platelets yielded similar thrombin generation rates but reduced phosphatidylserine expression as compared to adult platelets. Interestingly, we observed enhanced P2Y1/P2Y12-mediated dense granule trafficking in neonatal platelets relative to adults, although P2Y1/P2Y12 expression in neonatal, cord, and adult platelets were similar, suggesting that neonatal platelets may employ an ADP-mediated positive feedback loop as a potential compensatory mechanism for neonatal platelet hyporeactivity.
Collapse
Affiliation(s)
- Anh T.P. Ngo
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Jawaad Sheriff
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Anne D. Rocheleau
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Matthew Bucher
- Knight Cardiovascular Institute, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
- Department of Obstetrics and Gynecology, Oregon Health
& Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Kendra R. Jones
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Anna-Liisa I. Sepp
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Lisa E. Malone
- Division of Hematology, Department of Medicine, Stony Brook
University, Stony Brook, NY, USA 11794
| | - Amanda Zigomalas
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Alina Maloyan
- Knight Cardiovascular Institute, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
- Department of Obstetrics and Gynecology, Oregon Health
& Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Wadie F. Bahou
- Division of Hematology, Department of Medicine, Stony Brook
University, Stony Brook, NY, USA 11794
| | - Danny Bluestein
- Department of Biomedical Engineering; Stony Brook
University, Stony Brook, NY, USA 11794
| | - Owen J. T. McCarty
- Department of Biomedical Engineering, Oregon Health &
Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| | - Kristina M. Haley
- The Hemophilia Center, Oregon Health & Science
University, 3181 SW Sam Jackson Park Rd, Portland, OR, USA 97239
| |
Collapse
|
22
|
Mohamed AAB, Elnady HM, Alhewaig HK, Moslem Hefny H, Khodery A. The mean platelet volume and plateletcrit as predictors of short-term outcome of acute ischemic stroke. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2019; 55:4. [PMID: 30686914 PMCID: PMC6325094 DOI: 10.1186/s41983-018-0035-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 10/23/2018] [Indexed: 02/07/2023] Open
Abstract
Background Activation of the platelet plays an important role in the process of atherosclerosis. Mean platelet volume (MPV) is significantly associated with the poor outcome of acute ischemic stroke while the results of studies about the relationship between plateletcrit (PCT) and stroke outcome were inconsistent. The aim of this work is to determine whether an association exists between MPV and plateletcrit (PCT) and outcome of acute ischemic stroke. Methods We examined 157 patients with ischemic stroke, admitted to the Sohag University Hospital. The diagnosis of stroke was performed clinically according to The World Health Organization and confirmed by brain CT and MRI when needed. Platelet indices including MPV and PCT were assessed immediately (within 2 h) after admission. After 3 months, the functional outcome was assessed using the modified Rankin Scale (mRS) with assessment of the relationship between platelet indices and stroke outcome. Results About 50% of the participants have favorable outcome. MPV was significantly higher in the unfavorable group (10.4 ± 2.3 fL) than in the favorable one (8.7 ± 1.3 fL) (P < 0. 001). MPV was an independent predictor of poor short-term outcome of acute stroke after controlling for confounders like diabetes mellitus. The mean PCT was significantly higher in the unfavorable group (0.28 ± 0.1%) than in the favorable one (0.25 ± 0.1%) (P = 0. 04) but not considered as an independent predictor of poor short-term outcome of acute stroke. Conclusions MPV and PCT were significantly correlated with poor functional outcome, only MPV was an independent predictor of poor short-term outcome of acute stroke after controlling for confounders like DM, and these platelet indices can be used as a prognostic tool.
Collapse
Affiliation(s)
- Al-Amir Bassiouny Mohamed
- 1Department of Neurology and Psychological Medicine, Faculty of Medicine, Sohag University Hospital, Sohag, Egypt
| | - Hassan Mohamed Elnady
- 1Department of Neurology and Psychological Medicine, Faculty of Medicine, Sohag University Hospital, Sohag, Egypt
| | - Hazem Kamal Alhewaig
- 1Department of Neurology and Psychological Medicine, Faculty of Medicine, Sohag University Hospital, Sohag, Egypt
| | - Hesham Moslem Hefny
- 2Department of Clinical Pathology, Faculty of Medicine, Sohag University Hospital, Sohag, Egypt
| | - Ashraf Khodery
- 2Department of Clinical Pathology, Faculty of Medicine, Sohag University Hospital, Sohag, Egypt
| |
Collapse
|
23
|
Rotman OM, Bianchi M, Ghosh RP, Kovarovic B, Bluestein D. Principles of TAVR valve design, modelling, and testing. Expert Rev Med Devices 2018; 15:771-791. [PMID: 30318937 PMCID: PMC6417919 DOI: 10.1080/17434440.2018.1536427] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Transcatheter aortic valve replacement (TAVR) has emerged as an effective minimally-invasive alternative to surgical valve replacement in medium- to high-risk, elderly patients with calcific aortic valve disease and severe aortic stenosis. The rapid growth of the TAVR devices market has led to a high variety of designs, each aiming to address persistent complications associated with TAVR valves that may hamper the anticipated expansion of TAVR utility. AREAS COVERED Here we outline the challenges and the technical demands that TAVR devices need to address for achieving the desired expansion, and review design aspects of selected, latest generation, TAVR valves of both clinically-used and investigational devices. We further review in detail some of the up-to-date modeling and testing approaches for TAVR, both computationally and experimentally, and additionally discuss those as complementary approaches to the ISO 5840-3 standard. A comprehensive survey of the prior and up-to-date literature was conducted to cover the most pertaining issues and challenges that TAVR technology faces. EXPERT COMMENTARY The expansion of TAVR over SAVR and to new indications seems more promising than ever. With new challenges to come, new TAV design approaches, and materials used, are expected to emerge, and novel testing/modeling methods to be developed.
Collapse
Affiliation(s)
- Oren M. Rotman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Matteo Bianchi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ram P. Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Brandon Kovarovic
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| |
Collapse
|
24
|
Strongly Coupled Morphological Features of Aortic Aneurysms Drive Intraluminal Thrombus. Sci Rep 2018; 8:13273. [PMID: 30185838 PMCID: PMC6125404 DOI: 10.1038/s41598-018-31637-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/15/2018] [Indexed: 01/13/2023] Open
Abstract
Over 75% of abdominal aortic aneurysms harbor an intraluminal thrombus, and increasing evidence suggests that biologically active thrombus contributes to the natural history of these potentially lethal lesions. Thrombus formation depends on the local hemodynamics, which in turn depends on morphological features of the aneurysm and near vasculature. We previously presented a hemodynamically motivated “thrombus formation potential” that predicts where and when thrombus might form. Herein, we combine detailed studies of the three-dimensional hemodynamics with methods of sparse grid collocation and interpolation via kriging to examine roles of five key morphological features of aneurysms on thrombus formation: lesion diameter, axial position, length, curvature, and renal artery position. Computational simulations suggest that maximum diameter is a key determinant of thrombogenicity, but other morphological features modulate this dependence. More distally located lesions tend to have a higher thrombus formation potential and shorter lesions tend to have a higher potential than longer lesions, given the same aneurysmal dilatation. Finally, movement of vortical structures through the infrarenal aorta and lesion can significantly affect thrombogenicity. Formation of intraluminal thrombus within an evolving abdominal aortic aneurysm thus depends on coupled morphological features, not all intuitive, and computational simulations can be useful for predicting thrombogenesis.
Collapse
|
25
|
Abstract
This overview article for the Comprehensive Physiology collection is focused on detailing platelets, how platelets respond to various stimuli, how platelets interact with their external biochemical environment, and the role of platelets in physiological and pathological processes. Specifically, we will discuss the four major functions of platelets: activation, adhesion, aggregation, and inflammation. We will extend this discussion to include various mechanisms that can induce these functional changes and a discussion of some of the salient receptors that are responsible for platelets interacting with their external environment. We will finish with a discussion of how platelets interact with their vascular environment, with a special focus on interactions with the extracellular matrix and endothelial cells, and finally how platelets can aid and possibly initiate the progression of various vascular diseases. Throughout this overview, we will highlight both the historical investigations into the role of platelets in health and disease as well as some of the more current work. Overall, the authors aim for the readers to gain an appreciation for the complexity of platelet functions and the multifaceted role of platelets in the vascular system. © 2017 American Physiological Society. Compr Physiol 8:1117-1156, 2018.
Collapse
Affiliation(s)
- David A Rubenstein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| | - Wei Yin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA
| |
Collapse
|
26
|
Hardersen R, Enebakk T, Christiansen D, Bergseth G, Brekke OL, Mollnes TE, Lappegård KT, Hovland A. Granulocyte and monocyte CD11b expression during plasma separation is dependent on complement factor 5 (C5) - an ex vivo study with blood from a C5-deficient individual. APMIS 2018; 126:342-352. [PMID: 29575196 DOI: 10.1111/apm.12821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 01/21/2018] [Indexed: 12/18/2022]
Abstract
The aim of the study was to investigate the role of complement factor 5 (C5) in reactions elicited by plasma separation using blood from a C5-deficient (C5D) individual, comparing it to C5-deficient blood reconstituted with C5 (C5DR) and blood from healthy donors. Blood was circulated through an ex vivo plasma separation model. Leukocyte CD11b expression and leukocyte-platelet conjugates were measured by flow cytometry during a 30-min period. Other markers were assessed during a 240-min period. Granulocyte and monocyte CD11b expression did not increase in C5D blood during plasma separation. In C5DR samples granulocytes CD11b expression, measured by mean fluorescence intensity (MFI), increased from 10481 ± 6022 (SD) to 62703 ± 4936, and monocytes CD11b expression changed from 13837 ± 7047 to 40063 ± 713. Granulocyte-platelet conjugates showed a 2.5-fold increase in the C5DR sample compared to the C5D sample. Monocyte-platelet conjugates increased independently of C5. In the C5D samples, platelet count decreased from 210 × 109 /L (201-219) (median and range) to 51 × 109 /L (50-51), and C3bc increased from 14 CAU/mL (21-7) to 198 CAU/mL (127-269), whereas TCC formation was blocked during plasma separation. In conclusion, up-regulation of granulocyte and monocyte CD11b during plasma separation was C5-dependent. The results also indicate C5 dependency in granulocyte-platelet conjugates formation.
Collapse
Affiliation(s)
- Randolf Hardersen
- Department of Nephrology, Division of Internal Medicine, Nordland Hospital, Bodø, Norway
| | - Terje Enebakk
- Department of Nephrology, Division of Internal Medicine, Nordland Hospital, Bodø, Norway
| | | | | | - Ole-Lars Brekke
- Institute of Clinical Medicine and K. G. Jebsen TREC, University of Tromsø, Tromsø, Norway.,Department of Laboratory Medicine, Nordland Hospital, Bodø, Norway
| | - Tom Eirik Mollnes
- Research Laboratory, Nordland Hospital, Bodø, Norway.,Institute of Clinical Medicine and K. G. Jebsen TREC, University of Tromsø, Tromsø, Norway.,Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway.,K.J. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Immunology, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Knut Tore Lappegård
- Institute of Clinical Medicine and K. G. Jebsen TREC, University of Tromsø, Tromsø, Norway.,Department of Cardiology, Division of Internal Medicine, Nordland Hospital, Bodø, Norway
| | - Anders Hovland
- Institute of Clinical Medicine and K. G. Jebsen TREC, University of Tromsø, Tromsø, Norway.,Department of Cardiology, Division of Internal Medicine, Nordland Hospital, Bodø, Norway
| |
Collapse
|
27
|
Wain RAJ, Smith DJ, Hammond DR, Whitty JPM. Influence of microvascular sutures on shear strain rate in realistic pulsatile flow. Microvasc Res 2018. [PMID: 29522755 DOI: 10.1016/j.mvr.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Arterial thrombus formation is directly related to the mechanical shear experienced by platelets within flow. High shear strain rates (SSRs) and large shear gradients cause platelet activation, aggregation and production of thrombus. This study, for the first time, investigates the influence of pulsatile flow on local haemodynamics within sutured microarterial anastomoses. We measured physiological arterial waveform velocities experimentally using Doppler ultrasound velocimetry, and a representative example was applied to a realistic sutured microarterial geometry. Computational geometries were created using measurements taken from sutured chicken femoral arteries. Arterial SSRs were predicted using computational fluid dynamics (CFD) software, to indicate the potential for platelet activation, deposition and thrombus formation. Predictions of steady and sinusoidal inputs were compared to analyse whether the addition of physiological pulse characteristics affects local intravascular flow characteristics. Simulations were designed to evaluate flow in pristine and hand-sutured microarterial anastomoses, each with a steady-state and sinusoidal pulse component. The presence of sutures increased SSRmax in the anastomotic region by factors of 2.1 and 2.3 in steady-state and pulsatile flows respectively, when compared to a pristine vessel. SSR values seen in these simulations are analogous to the presence of moderate arterial stenosis. Steady-state simulations, driven by a constant inflow velocity equal to the peak systolic velocity (PSV) of the measured pulsatile flow, underestimated SSRs by ∼ 9% in pristine, and ∼ 19% in sutured vessels compared with a realistic pulse. Sinusoidal flows, with equivalent frequency and amplitude to a measured arterial waveform, represent a slight improvement on steady-state simulations, but still SSRs are underestimated by 1-2%. We recommend using a measured arterial waveform, of the form presented here, for simulating pulsatile flows in vessels of this nature. Under realistic pulsatile flow, shear gradients across microvascular sutures are high, of the order ∼ 7.9 × 106 m-1 s-1, which may also be associated with activation of platelets and formation of aggregates.
Collapse
Affiliation(s)
- R A J Wain
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute of Translational Medicine, University of Birmingham, B15 2TT, UK; School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK; Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK.
| | - D J Smith
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute for Metabolism and Systems Research, University of Birmingham, B15 2TT, UK
| | - D R Hammond
- School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - J P M Whitty
- Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK
| |
Collapse
|
28
|
Méndez Rojano R, Mendez S, Nicoud F. Introducing the pro-coagulant contact system in the numerical assessment of device-related thrombosis. Biomech Model Mechanobiol 2018; 17:815-826. [PMID: 29302840 DOI: 10.1007/s10237-017-0994-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/14/2017] [Indexed: 11/28/2022]
Abstract
Thrombosis is a major concern in blood-coated medical devices. Contact activation, which is the initial part of the coagulation cascade in device-related thrombosis, is not considered in current thrombus formation models. In the present study, pro-coagulant reactions including the contact activation system are coupled with a fluid solver in order to evaluate the potential of the contact system to initiate thrombin production. The biochemical/fluid model is applied to a backward-facing step configuration, a flow configuration that frequently appears in medical devices. In contrast to the in vivo thrombosis models in which a specific thrombotic zone (injury region) is set a priori by the user to initiate the coagulation reaction, a reactive surface boundary condition is applied to the whole device wall. Simulation results show large thrombin concentration in regions related to recirculation zones without the need of an a priori knowledge of the thrombus location. The numerical results align well with the regions prone to thrombosis observed in experimental results reported in the literature. This approach could complement thrombus formation models that take into account platelet activity and thrombus growth to optimize a wide range of medical devices.
Collapse
Affiliation(s)
- Rodrigo Méndez Rojano
- Institut Montpelliérain Alexander Grothendieck, CNRS, Univ. Montpellier, 2 Place Eugène Bataillon, 34095, Montpellier Cedex 5, France.
| | - Simon Mendez
- Institut Montpelliérain Alexander Grothendieck, CNRS, Univ. Montpellier, 2 Place Eugène Bataillon, 34095, Montpellier Cedex 5, France
| | - Franck Nicoud
- Institut Montpelliérain Alexander Grothendieck, CNRS, Univ. Montpellier, 2 Place Eugène Bataillon, 34095, Montpellier Cedex 5, France
| |
Collapse
|
29
|
Consolo F, Sferrazza G, Motolone G, Contri R, Valerio L, Lembo R, Pozzi L, Della Valle P, De Bonis M, Zangrillo A, Fiore GB, Redaelli A, Slepian MJ, Pappalardo F. Platelet activation is a preoperative risk factor for the development of thromboembolic complications in patients with continuous-flow left ventricular assist device. Eur J Heart Fail 2017; 20:792-800. [DOI: 10.1002/ejhf.1113] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/23/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Filippo Consolo
- Università Vita Salute San Raffaele; Milan Italy
- Department of Electronics; Information and Bioengineering, Politecnico di Milano; Milan Italy
| | - Giulia Sferrazza
- Department of Electronics; Information and Bioengineering, Politecnico di Milano; Milan Italy
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| | - Giulia Motolone
- Department of Electronics; Information and Bioengineering, Politecnico di Milano; Milan Italy
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| | - Rachele Contri
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| | - Lorenzo Valerio
- Department of Electronics; Information and Bioengineering, Politecnico di Milano; Milan Italy
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| | - Rosalba Lembo
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| | - Loris Pozzi
- Coagulation Service and Thrombosis Research Unit; San Raffaele Scientific Institute; Milan Italy
| | - Patrizia Della Valle
- Coagulation Service and Thrombosis Research Unit; San Raffaele Scientific Institute; Milan Italy
| | | | - Alberto Zangrillo
- Università Vita Salute San Raffaele; Milan Italy
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| | - Gianfranco B. Fiore
- Department of Electronics; Information and Bioengineering, Politecnico di Milano; Milan Italy
| | - Alberto Redaelli
- Department of Electronics; Information and Bioengineering, Politecnico di Milano; Milan Italy
| | - Marvin J. Slepian
- Department of Medicine and Biomedical Engineering, Sarver Heart Center; The University of Arizona; Tucson AZ USA
| | - Federico Pappalardo
- Università Vita Salute San Raffaele; Milan Italy
- Anesthesia and Cardiothoracic Intensive Care; San Raffaele Scientific Institute; Milan Italy
| |
Collapse
|
30
|
Valerio L, Sheriff J, Tran PL, Brengle W, Redaelli A, Fiore GB, Pappalardo F, Bluestein D, Slepian MJ. Routine clinical anti-platelet agents have limited efficacy in modulating hypershear-mediated platelet activation associated with mechanical circulatory support. Thromb Res 2017; 163:162-171. [PMID: 29428715 DOI: 10.1016/j.thromres.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/03/2017] [Accepted: 12/02/2017] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Continuous flow ventricular assist devices (cfVADs) continue to be limited by thrombotic complications associated with disruptive flow patterns and supraphysiologic shear stresses. Patients are prescribed complex antiplatelet therapies, which do not fully prevent recurrent thromboembolic events. This is partially due to limited data on antiplatelet efficacy under cfVAD-associated shear conditions. MATERIALS AND METHODS We investigated the efficacy of antiplatelet drugs directly acting on three pathways: (1) cyclooxygenase (aspirin), (2) phosphodiesterase (dipyridamole, pentoxifylline, cilostazol), and (3) glycoprotein IIb-IIIa (eptifibatide). Gel-filtered platelets treated with these drugs were exposed for 10min to either constant shear stresses (30dyne/cm2 and 70dyne/cm2) or dynamic shear stress profiles extracted from simulated platelet trajectories through a cfVAD (Micromed DeBakey). Platelet activation state (PAS) was measured using a modified prothrombinase-based assay, with drug efficacy quantified based on PAS reduction compared to untreated controls. RESULTS AND CONCLUSIONS Significant PAS reduction was observed for all drugs after exposure to 30dyne/cm2 constant shear stress, and all drugs but dipyridamole after exposure to the 30th percentile shear stress waveform of the cfVAD. However, only cilostazol was significantly effective after 70dyne/cm2 constant shear stress exposure, though no significant reduction was observed upon exposure to median shear stress conditions in the cfVAD. These results, coupled with the persistence of reported clinical thrombotic complication, suggest the need for the development of new classes of drugs that are especially designed to mitigate thrombosis in cfVAD patients, while reducing or eliminating the risk of bleeding.
Collapse
Affiliation(s)
- Lorenzo Valerio
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy; Department of Cardiothoracic Anesthesia and Intensive Care, Istituto Scientifico San Raffaele, Milan, Italy
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Phat L Tran
- Department of Biomedical Engineering, Sarver Heart Center, University of Arizona, Tucson, AZ, USA
| | - William Brengle
- Department of Biomedical Engineering, Sarver Heart Center, University of Arizona, Tucson, AZ, USA
| | - Alberto Redaelli
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Gianfranco B Fiore
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Federico Pappalardo
- Department of Cardiothoracic Anesthesia and Intensive Care, Istituto Scientifico San Raffaele, Milan, Italy
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Marvin J Slepian
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA; Department of Biomedical Engineering, Sarver Heart Center, University of Arizona, Tucson, AZ, USA; Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ, USA.
| |
Collapse
|
31
|
Hosseinipour M, Gupta R, Bonnell M, Elahinia M. Rotary mechanical circulatory support systems. J Rehabil Assist Technol Eng 2017; 4:2055668317725994. [PMID: 31186935 PMCID: PMC6453075 DOI: 10.1177/2055668317725994] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 07/20/2017] [Indexed: 12/25/2022] Open
Abstract
A detailed survey of the current trends and recent advances in rotary mechanical
circulatory support systems is presented in this paper. Rather than clinical reports, the
focus is on technological aspects of these rehabilitating devices as a reference for
engineers and biomedical researchers. Existing trends in flow regimes, flow control, and
bearing mechanisms are summarized. System specifications and applications of the most
prominent continuous-flow ventricular assistive devices are provided. Based on the flow
regime, pumps are categorized as axial flow, centrifugal flow, and mixed flow. Unique
characteristics of each system are unveiled through an examination of the structure,
bearing mechanism, impeller design, flow rate, and biocompatibility. A discussion on the
current limitations is provided to invite more studies and further improvements.
Collapse
Affiliation(s)
- Milad Hosseinipour
- Dynamic and Smart Systems Laboratory, The University of Toledo, Toledo, OH, USA.,Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Rajesh Gupta
- Cardiovascular Medicine Division, The University of Toledo Medical Center, Toledo, OH, USA
| | - Mark Bonnell
- Cardiothoracic Surgery Division, The University of Toledo Medical Center, Toledo, OH, USA
| | - Mohammad Elahinia
- Dynamic and Smart Systems Laboratory, The University of Toledo, Toledo, OH, USA
| |
Collapse
|
32
|
Review of numerical methods for simulation of mechanical heart valves and the potential for blood clotting. Med Biol Eng Comput 2017; 55:1519-1548. [DOI: 10.1007/s11517-017-1688-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/10/2017] [Indexed: 11/26/2022]
|
33
|
Hosseinzadegan H, Tafti DK. Modeling thrombus formation and growth. Biotechnol Bioeng 2017; 114:2154-2172. [DOI: 10.1002/bit.26343] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/03/2017] [Accepted: 05/16/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Hamid Hosseinzadegan
- Mechanical Engineering DepartmentVirginia Polytechnic Institute and State University, 213E Goodwin Hall ‐ 0238, 635 Prices Fork RoadBlacksburgVirginia24061
| | - Danesh K. Tafti
- Mechanical Engineering DepartmentVirginia Polytechnic Institute and State University, 213E Goodwin Hall ‐ 0238, 635 Prices Fork RoadBlacksburgVirginia24061
| |
Collapse
|
34
|
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;,
| |
Collapse
|
35
|
Zhang L, Casey B, Galanakis DK, Marmorat C, Skoog S, Vorvolakos K, Simon M, Rafailovich MH. The influence of surface chemistry on adsorbed fibrinogen conformation, orientation, fiber formation and platelet adhesion. Acta Biomater 2017; 54:164-174. [PMID: 28263863 DOI: 10.1016/j.actbio.2017.03.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 02/15/2017] [Accepted: 03/01/2017] [Indexed: 10/20/2022]
Abstract
Thrombosis is a clear risk when any foreign material is in contact with the bloodstream. Here we propose an immunohistological stain-based model for non-enzymatic clot formation that enables a facile screen for the thrombogenicity of blood-contacting materials. We exposed polymers with different surface chemistries to protease-free human fibrinogen. We observed that on hydrophilic surfaces, fibrinogen is adsorbed via αC regions, while the γ400-411 platelet-binding dodecapeptide on the D region becomes exposed, and fibrinogen fibers do not form. In contrast, fibrinogen is adsorbed on hydrophobic surfaces via the relatively hydrophobic D and E regions, exposing the αC regions while rendering the γ400-411 inaccessible. Fibrinogen adsorbed on hydrophobic surfaces is thus able to recruit other fibrinogen molecules through αC regions and polymerize into large fibrinogen fibers, similar to those formed in vivo in the presence of thrombin. Moreover, the γ400-411 is available only on the large fibers not elsewhere throughout the hydrophobic surface after fibrinogen fiber formation. When these surfaces were exposed to gel-sieved platelets or platelet rich plasma, a uniform monolayer of platelets, which appeared to be activated, was observed on the hydrophilic surfaces. In contrast, large agglomerates of platelets were clustered on fibers on the hydrophobic surfaces, resembling small nucleating thrombi. Endothelial cells were also able to adhere to the monomeric coating of fibrinogen on hydrophobic surfaces. These observations reveal that the extent and type of fibrinogen adsorption, as well as the propensity of adsorbed fibrinogen to bind platelets, may be modulated by careful selection of surface chemistry. STATEMENTS OF SIGNIFICANCE Thrombosis is a well-known side effect of the introduction of foreign materials into the bloodstream, as might exist in medical devices including but not limited to stents, valves, and intravascular catheters. Despite many reported studies, the body's response to foreign materials in contact with the blood remains poorly understood. Current preventive methods consist of drug eluting coatings on the devices or the systemic administration of standard anticoagulants. Here we present a potential mechanism by which surface chemistry can affects fibrinogen conformation and thus affects platelet adhesion and consequently thrombus formation. Our findings suggest a possible coating which enables endothelial cell adhesion while preventing platelet adhesion.
Collapse
|
36
|
Shin DH, Rhee SY, Jeon HJ, Park JY, Kang SW, Oh J. An Increase in Mean Platelet Volume/Platelet Count Ratio Is Associated with Vascular Access Failure in Hemodialysis Patients. PLoS One 2017; 12:e0170357. [PMID: 28095482 PMCID: PMC5240979 DOI: 10.1371/journal.pone.0170357] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/03/2017] [Indexed: 12/05/2022] Open
Abstract
After stenosis of arteriovenous vascular access in hemodialysis patients, platelets play a crucial role in subsequent thrombus formation, leading to access failure. In a previous study, the mean platelet volume (MPV)/platelet count ratio, but not MPV alone, was shown to be an independent predictor of 4-year mortality after myocardial infarction. However, little is known about the potential influence of MPV/platelet count ratio on vascular access patency in hemodialysis patients. A total of 143 patients undergoing routine hemodialysis were recruited between January 2013 and February 2016. Vascular access failure (VAF) was defined as thrombosis or a decrease of greater than 50% of normal vessel diameter, requiring either surgical revision or percutaneous transluminal angioplasty. Cox proportional hazards model analysis ascertained that the change of MPV/platelet count ratio between baseline and 3 months [Δ(MPV/platelet count ratio)3mo-baseline] had prognostic value for VAF. Additionally, the changes of MPV/platelet count ratio over time were compared in patients with and without VAF by using linear mixed model analysis. Of the 143 patients, 38 (26.6%) were diagnosed with VAF. During a median follow-up of 26.9 months (interquartile range 13.0–36.0 months), Δ(MPV/platelet count ratio)3mo-baseline significantly increased in patients with VAF compared to that in patients without VAF [11.6 (6.3–19.0) vs. 0.8 (-1.8–4.0), P< 0.001]. In multivariate analysis, Δ(MPV/platelet ratio count)3mo-baseline was an independent predictor of VAF, after adjusting for age, sex, diabetes, hypertension, coronary artery disease, cerebrovascular disease, vascular access type, the presence of previous VAF, and antiplatelet drug use (hazard ratio, 1.15; 95% confidence interval, 1.10–1.21; P< 0.001). Moreover, a liner mixed model revealed that there was a significant increase of MPV/platelet count ratio over time in patients with VAF compared to those without VAF (P< 0.001). An increase in MPV/platelet count ratio over time was an independent risk factor for VAF. Therefore, continuous monitoring of the MPV/platelet count ratio may be useful to screen the risk of VAF in patients undergoing routine hemodialysis.
Collapse
Affiliation(s)
- Dong Ho Shin
- Department of Internal Medicine, College of Medicine, Kangdong Sacred Heart Hospital, Hallym University, Seoul, Korea
- Department of Medicine, Graduate School of Medicine, Yonsei University, Seoul, Korea
| | - So Yon Rhee
- Department of Internal Medicine, College of Medicine, Kangdong Sacred Heart Hospital, Hallym University, Seoul, Korea
| | - Hee Jung Jeon
- Department of Internal Medicine, College of Medicine, Kangdong Sacred Heart Hospital, Hallym University, Seoul, Korea
| | - Ji-Young Park
- Department of Laboratory Medicine, College of Medicine, Kangdong Sacred Heart Hospital, Hallym University, Seoul, Korea
| | - Shin-Wook Kang
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Jieun Oh
- Department of Internal Medicine, College of Medicine, Kangdong Sacred Heart Hospital, Hallym University, Seoul, Korea
- Hallym Kidney Research Institute, Hallym University, Seoul, Korea
- * E-mail:
| |
Collapse
|
37
|
Ku DN, Casa LDC, Hastings SM. Choice of a hemodynamic model for occlusive thrombosis in arteries. J Biomech 2017; 50:110-113. [PMID: 27899178 DOI: 10.1016/j.jbiomech.2016.11.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 11/05/2016] [Indexed: 10/20/2022]
Abstract
Intravascular thrombosis can lead to heart attacks and strokes that together are the leading causes of death in the US (Kochanek, K.D., Murphy, S.L., Xu, J.Q., 2014). The ability to identify the offending biofluid mechanical conditions and predict the timescale of thrombotic occlusion in vessels and devices may improve patient outcomes. A computational model was developed to describe the growth of thrombus based on the local hemodynamic shear rate. The model predicts thrombus deposition based on initial geometric and fluid mechanical conditions, which are updated throughout the simulation to reflect the changing lumen dimensions. Thrombus growth and occlusion from whole blood was measured in in vitro experiments using stenotic glass capillary tubes, a PDMS microfluidic channel, and a PTFE stenotic aorto-iliac graft. Comparison of the predicted occlusion times to experimental results shows excellent agreement. The results indicate that local shear rate plays a critical role in acute thrombosis, and that hemodynamic characterization may have clinical utility.
Collapse
Affiliation(s)
- David N Ku
- G.W. Woodruff School of Mechanical Engineering Georgia Institute of Technology, USA.
| | - Lauren D C Casa
- G.W. Woodruff School of Mechanical Engineering Georgia Institute of Technology, USA
| | - Susan M Hastings
- G.W. Woodruff School of Mechanical Engineering Georgia Institute of Technology, USA
| |
Collapse
|
38
|
Microarterial anastomoses: A parameterised computational study examining the effect of suture position on intravascular blood flow. Microvasc Res 2016; 105:141-8. [DOI: 10.1016/j.mvr.2016.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 02/04/2016] [Accepted: 02/04/2016] [Indexed: 11/19/2022]
|
39
|
Ou C, Huang W, Yuen MMF. A computational model based on fibrin accumulation for the prediction of stasis thrombosis following flow-diverting treatment in cerebral aneurysms. Med Biol Eng Comput 2016; 55:89-99. [PMID: 27106753 DOI: 10.1007/s11517-016-1501-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/27/2016] [Indexed: 01/09/2023]
Abstract
Flow diverters, the specially designed low porosity stents, have been used to redirect blood flow from entering aneurysm, which induces flow stasis in aneurysm and promote thrombosis for repairing aneurysm. However, it is not clear how thrombus develops following flow-diversion treatment. Our objective was to develop a computation model for the prediction of stasis-induced thrombosis following flow-diversion treatment in cerebral aneurysms. We proposed a hypothesis to initiate coagulation following flow-diversion treatment. An experimental model was used by ligating rat's right common carotid artery (RCCA) to create flow-stasis environment. Thrombus formed in RCCA as a result of flow stasis. The fibrin distributions in different sections along the axial length of RCCA were measured. The fibrin distribution predicted by our computational model displayed a trend of increase from the proximal neck to the distal tip, consistent with the experimental results on rats. The model was applied on a saccular aneurysm treated with flow diverter to investigate thrombus development following flow diversion. Thrombus was predicted to form inside the sac, and the aneurysm was occluded with only a small remnant neck remained. Our model can serve as a tool to evaluate flow-diversion treatment outcome and optimize the design of flow diverters.
Collapse
Affiliation(s)
- Chubin Ou
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Wei Huang
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Matthew Ming-Fai Yuen
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
- Division of Biomedical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
| |
Collapse
|
40
|
Hom S, Chen L, Wang T, Ghebrehiwet B, Yin W, Rubenstein DA. Platelet activation, adhesion, inflammation, and aggregation potential are altered in the presence of electronic cigarette extracts of variable nicotine concentrations. Platelets 2016; 27:694-702. [PMID: 27096416 DOI: 10.3109/09537104.2016.1158403] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Tobacco smoke extracts prepared from both mainstream and sidestream smoking have been associated with heightened platelet activation, aggregation, adhesion, and inflammation. Conversely, it has been shown that pure nicotine inhibits similar platelet functions. In this work, we 1) evaluated the effects of e-cigarette extracts on platelet activities and 2) elucidated the differences between the nicotine-dependent and non-nicotine dependent (e.g. fine particulate matter or toxic compounds) effects of tobacco and e-cigarette products on platelet activities. To accomplish these goals, platelets from healthy volunteers (n = 50) were exposed to tobacco smoke extracts, e-cigarette vapor extracts, and pure nicotine and changes in platelet activation, adhesion, aggregation, and inflammation were evaluated, using optical aggregation, flow cytometry, and ELISA methods. Interestingly, the exposure of platelets to e-vapor extracts induced a significant up-regulation in the expression of the pro-inflammatory gC1qR and cC1qR and induced a marked increase in the deposition of C3b as compared with traditional tobacco smoke extracts. Similarly, platelet activation, as measured by a prothrombinase based assay, and platelet aggregation were also significantly enhanced after exposure to e-vapor extracts. Finally, platelet adhesion potential toward fibrinogen, von Willebrand factor, and other platelets was also enhanced after exposure to e-cigarette vapor extracts. In the presence of pure nicotine, platelet functions were observed to be inhibited, which further suggests that other constituents of tobacco smoke and electronic vapor can antagonize platelet functions, however, the presence of nicotine in extracts somewhat perpetuated the platelet functional changes in a dose-dependent manner.
Collapse
Affiliation(s)
- Sarah Hom
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| | - Li Chen
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| | - Tony Wang
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| | - Berhane Ghebrehiwet
- b School of Medicine, Department of Medicine , Stony Brook University , Stony Brook , NY , USA
| | - Wei Yin
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| | - David A Rubenstein
- a Department of Biomedical Engineering , Stony Brook University , Stony Brook , NY , USA
| |
Collapse
|
41
|
Valerio L, Tran PL, Sheriff J, Brengle W, Ghosh R, Chiu WC, Redaelli A, Fiore GB, Pappalardo F, Bluestein D, Slepian MJ. Aspirin has limited ability to modulate shear-mediated platelet activation associated with elevated shear stress of ventricular assist devices. Thromb Res 2016; 140:110-117. [PMID: 26938158 DOI: 10.1016/j.thromres.2016.01.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 01/25/2016] [Accepted: 01/31/2016] [Indexed: 10/22/2022]
Abstract
Continuous flow ventricular assist devices (cfVADs) while effective in advanced heart failure, remain plagued by thrombosis related to abnormal flows and elevated shear stress. To limit cfVAD thrombosis, patients utilize complex anti-thrombotic regimens built upon a foundation of aspirin (ASA). While much data exists on ASA as a modulator of biochemically-mediated platelet activation, limited data exists as to the efficacy of ASA as a means of limiting shear-mediated platelet activation, particularly under elevated shear stress common within cfVADs. We investigated the ability of ASA (20, 25 and 125 μM) to limit shear-mediated platelet activation under conditions of: 1) constant shear stress (30 dynes/cm(2) and 70 dynes/cm(2)); 2) dynamic shear stress, and 3) initial high shear exposure (70 dynes/cm(2)) followed by low shear exposure - i.e. a platelet sensitization protocol, utilizing a hemodynamic shearing device providing uniform shear stress in vitro. The efficacy of ASA to limit platelet activation mediated via passage through a clinical cfVAD system (DeBakey Micromed) in vitro was also studied. ASA reduced platelet activation only under conditions of low shear stress (38% reduction compared to control, n=10, p<0.004), with minimal protection at higher shear stress and under dynamic conditions (n=10, p>0.5) with no limitation of platelet sensitization. ASA had limited ability (25.6% reduction in platelet activation rate) to modulate shear-mediated platelet activation induced via cfVAD passage. These findings, while performed under "deconstructed" non-clinical conditions by utilizing purified platelets alone in vitro, provide a potential contributory mechanistic explanation for the persistent thrombosis rates experienced clinically in cfVAD patients despite ASA therapy. An opportunity exists to develop enhanced pharmacologic strategies to limit shear-mediated platelet activation at elevated shear levels associated with mechanical circulatory support devices.
Collapse
Affiliation(s)
- Lorenzo Valerio
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy; Department of Cardiothoracic Anesthesia and Intensive Care, Istituto Scientifico San Raffaele, Milan, Italy.
| | - Phat L Tran
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - William Brengle
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA
| | - Ram Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Wei-Che Chiu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Alberto Redaelli
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Gianfranco B Fiore
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Federico Pappalardo
- Department of Cardiothoracic Anesthesia and Intensive Care, Istituto Scientifico San Raffaele, Milan, Italy
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Marvin J Slepian
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA; Department of Medicine, Sarver Heart Center, University of Arizona, Tucson, AZ, USA; Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| |
Collapse
|
42
|
Chesnutt JKW, Han HC. Computational simulation of platelet interactions in the initiation of stent thrombosis due to stent malapposition. Phys Biol 2016; 13:016001. [PMID: 26790093 DOI: 10.1088/1478-3975/13/1/016001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Coronary stenting is one of the most commonly used approaches to open coronary arteries blocked due to atherosclerosis. Stent malapposition can induce thrombosis but the microscopic process is poorly understood. The objective of this study was to determine the platelet-level process by which different extents of stent malapposition affect the initiation of stent thrombosis. We utilized a discrete element model to computationally simulate the transport, adhesion, and activation of thousands of individual platelets and red blood cells during thrombus initiation in stented coronary arteries. Simulated arteries contained a malapposed stent with a specified gap distance (0, 10, 25, 50, or 200 μm) between the struts and endothelium. Platelet-level details of thrombus formation near the proximal-most strut were measured during the simulations. The relationship between gap distance and amount of thrombus in the artery varied depending on different conditions (e.g., amount of dysfunctional endothelium, shear-induced activation of platelets, and thrombogenicity of the strut). Without considering shear-induced platelet activation, the largest gap distance (200 μm) produced no recirculation and less thrombus than the smallest two gap distances (0 and 10 μm) that created recirculation downstream of the strut. However, with the occurrence of shear-induced platelet activation, the largest gap distance produced more thrombus than the two smallest gap distances, but less thrombus than an intermediate gap distance (25 μm). A large gap distance was not necessarily the most thrombogenic, in contrast to implications of some computational fluid dynamics studies. The severity of stent malapposition affected initial stent thrombosis differently depending on various factors related to fluid recirculation, platelet trajectories, shear stress, and endothelial condition.
Collapse
Affiliation(s)
- Jennifer K W Chesnutt
- Cardiovascular Biomechanics Laboratory, Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA
| | | |
Collapse
|
43
|
Consolo F, Valerio L, Brizzola S, Rota P, Marazzato G, Vincoli V, Reggiani S, Redaelli A, Fiore G. On the Use of the Platelet Activity State Assay for the In Vitro Quantification of Platelet Activation in Blood Recirculating Devices for Extracorporeal Circulation. Artif Organs 2016; 40:971-980. [DOI: 10.1111/aor.12672] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Filippo Consolo
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| | - Lorenzo Valerio
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| | - Stefano Brizzola
- Dipartimento di Scienze Veterinarie per la Salute, la Produzione Animale e la Sicurezza Alimentare, Facoltà di Medicina Veterinaria; Università di Milano; Milano Italy
| | - Paolo Rota
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| | - Giulia Marazzato
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| | - Valentina Vincoli
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| | | | - Alberto Redaelli
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| | - Gianfranco Fiore
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano Italy
| |
Collapse
|
44
|
Dimasi A, Rasponi M, Sheriff J, Chiu WC, Bluestein D, Tran PL, Slepian MJ, Redaelli A. Microfluidic emulation of mechanical circulatory support device shear-mediated platelet activation. Biomed Microdevices 2015; 17:117. [PMID: 26578003 PMCID: PMC4855287 DOI: 10.1007/s10544-015-0015-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Thrombosis of ventricular assist devices (VADs) compromises their performance, with associated risks of systemic embolization, stroke, pump stop and possible death. Anti-thrombotic (AT) drugs, utilized to limit thrombosis, are largely dosed empirically, with limited testing of their efficacy. Further, such testing, if performed, typically examines efficacy under static conditions, which is not reflective of actual shear-mediated flow. Here we adopted our previously developed Device Thrombogenicity Emulation methodology to design microfluidic platforms able to emulate representative shear stress profiles of mechanical circulatory support (MCS) devices. Our long-term goal is to utilize these systems for point-of-care (POC) personalized testing of AT efficacy under specific, individual shear profiles. First, we designed different types of microfluidic channels able to replicate sample shear stress patterns observed in MCS devices. Second, we explored the flexibility of microfluidic technology in generating dynamic shear stress profiles by modulating the geometrical features of the channels. Finally, we designed microfluidic channel systems able to emulate the shear stress profiles of two commercial VADs. From CFD analyses, the VAD-emulating microfluidic systems were able to replicate the main characteristics of the shear stress waveforms of the macroscale VADs (i.e., shear stress peaks and duration). Our results establish the basis for development of a lab-on-chip POC system able to perform device-specific and patient-specific platelet activation state assays.
Collapse
Affiliation(s)
- Annalisa Dimasi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, 20133, Italy
| | - Marco Rasponi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, 20133, Italy
| | - Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Wei-Che Chiu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA
| | - Phat L Tran
- Department of Medicine and Biomedical Engineering, Sarver Heart Center, University of Arizona, 1501 North Campbell Avenue, Tucson, AZ, 85724, USA
| | - Marvin J Slepian
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA.
- Department of Medicine and Biomedical Engineering, Sarver Heart Center, University of Arizona, 1501 North Campbell Avenue, Tucson, AZ, 85724, USA.
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, 20133, Italy
| |
Collapse
|
45
|
Xie D, Leng Y, Jing F, Huang N. A brief review of bio-tribology in cardiovascular devices. BIOSURFACE AND BIOTRIBOLOGY 2015. [DOI: 10.1016/j.bsbt.2015.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
|
46
|
Altered Flow Changes Thrombin Generation Rate of Circulating Platelets. Ann Biomed Eng 2015; 43:2827-37. [DOI: 10.1007/s10439-015-1346-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/23/2015] [Indexed: 11/26/2022]
|
47
|
Sheriff J, Girdhar G, Chiu WC, Jesty J, Slepian MJ, Bluestein D. Comparative efficacy of in vitro and in vivo metabolized aspirin in the DeBakey ventricular assist device. J Thromb Thrombolysis 2015; 37:499-506. [PMID: 24043375 DOI: 10.1007/s11239-013-0997-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Ventricular assist devices (VADs) are implanted in patients with end-stage heart failure to provide both short- and long-term hemodynamic support. Unfortunately, bleeding and thromboembolic complications due to the severely disturbed, dynamic flow conditions generated within these devices require complex, long-term antiplatelet and anticoagulant therapy. While several studies have examined the effectiveness of one such agent, aspirin, under flow conditions, data comparing the efficacy of in vitro and in vivo metabolized aspirin is lacking. Two sets of studies were conducted in vitro with purified human platelets circulating for 30 min in a flow loop containing the DeBakey VAD (MicroMed Cardiovascular, Houston, TX, USA): (a) 20 μM aspirin was added exogenously in vitro to platelets isolated from aspirin-free subjects, and (b) platelets were obtained from donors 2 h (n = 14) and 20 h (n = 13) after ingestion of 1,000 mg aspirin. Near real-time platelet activation state (PAS) was measured with a modified prothrombinase-based assay. Platelets exposed to aspirin in vitro and in vivo (metabolized) showed 28.2 and 25.3 % reduction in platelet activation rate, respectively, compared to untreated controls. Our results demonstrate that in vitro treatment with antiplatelet drugs such as aspirin is as effective as in vivo metabolized aspirin in testing the effect of reducing shear-induced platelet activation in the VAD. Using the PAS assay provides a practical in vitro alternative to in vivo testing of antiplatelet efficacy, as well as for testing the thrombogenic performance of devices during their research and development.
Collapse
Affiliation(s)
- Jawaad Sheriff
- Department of Biomedical Engineering, Stony Brook University, T15-090 Health Sciences Center, Stony Brook, NY, 11794-8151, USA
| | | | | | | | | | | |
Collapse
|
48
|
Di Achille P, Tellides G, Figueroa CA, Humphrey JD. A haemodynamic predictor of intraluminal thrombus formation in abdominal aortic aneurysms. Proc Math Phys Eng Sci 2014. [DOI: 10.1098/rspa.2014.0163] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Intraluminal thrombus (ILT) is present in over 75% of all abdominal aortic aneurysms (AAAs) and probably contributes to the complex biomechanics and pathobiology of these lesions. A reliable predictor of thrombus formation in enlarging lesions could thereby aid clinicians in treatment planning. The primary goal of this work was to identify a new phenomenological metric having clinical utility that is motivated by the hypothesis that two basic haemodynamic features must coincide spatially and temporally to promote the formation of a thrombus on an intact endothelium—platelets must be activated within a shear flow and then be presented to a susceptible endothelium. Towards this end, we propose a new thrombus formation potential (TFP) that combines information on the flow-induced shear history experienced by blood-borne particles that come in close proximity to the endothelium with information on both the time-averaged wall shear stress (WSS) and the oscillatory shear index (OSI) that locally affect the endothelial mechanobiology. To illustrate the possible utility of this new metric, we show computational results for 10 carotid arteries from five patients where regions of low WSS and high OSI tend not to be presented with activated platelets (i.e. they have a low TFP), consistent with the thrombo-resistance of the healthy carotid despite its complex haemodynamics. Conversely, we show results for three patients that high TFP co-localizes with regions of observed thin thrombus in AAAs, which contrasts with findings of low TFP for the abdominal aorta of three healthy subjects. We submit that these promising results suggest the need for further consideration of the TFP, or a similar combined metric, as a potentially useful clinical predictor of the possible formation of ILT in AAAs.
Collapse
Affiliation(s)
- P. Di Achille
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - G. Tellides
- Department of Surgery, Yale School of Medicine, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| | - C. A. Figueroa
- Department of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - J. D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| |
Collapse
|
49
|
Pirbodaghi T, Asgari S, Cotter C, Bourque K. Physiologic and hematologic concerns of rotary blood pumps: what needs to be improved? Heart Fail Rev 2014; 19:259-66. [PMID: 23549998 DOI: 10.1007/s10741-013-9389-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Over the past few decades, advances in ventricular assist device (VAD) technology have provided a promising therapeutic strategy to treat heart failure patients. Despite the improved performance and encouraging clinical outcomes of the new generation of VADs based on rotary blood pumps (RBPs), their physiologic and hematologic effects are controversial. Currently, clinically available RBPs run at constant speed, which results in limited control over cardiac workload and introduces blood flow with reduced pulsatility into the circulation. In this review, we first provide an update on the new challenges of mechanical circulatory support using rotary pumps including blood trauma, increased non-surgical bleeding rate, limited cardiac unloading, vascular malformations, end-organ function, and aortic valve insufficiency. Since the non-physiologic flow characteristic of these devices is one of the main subjects of scientific debate in the literature, we next emphasize the latest research regarding the development of a pulsatile RBP. Finally, we offer an outlook for future research in the field.
Collapse
Affiliation(s)
- Tohid Pirbodaghi
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland,
| | | | | | | |
Collapse
|
50
|
Multiscale Particle-Based Modeling of Flowing Platelets in Blood Plasma Using Dissipative Particle Dynamics and Coarse Grained Molecular Dynamics. Cell Mol Bioeng 2014; 7:552-574. [PMID: 25530818 DOI: 10.1007/s12195-014-0356-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
We developed a multiscale particle-based model of platelets, to study the transport dynamics of shear stresses between the surrounding fluid and the platelet membrane. This model facilitates a more accurate prediction of the activation potential of platelets by viscous shear stresses - one of the major mechanisms leading to thrombus formation in cardiovascular diseases and in prosthetic cardiovascular devices. The interface of the model couples coarse-grained molecular dynamics (CGMD) with dissipative particle dynamics (DPD). The CGMD handles individual platelets while the DPD models the macroscopic transport of blood plasma in vessels. A hybrid force field is formulated for establishing a functional interface between the platelet membrane and the surrounding fluid, in which the microstructural changes of platelets may respond to the extracellular viscous shear stresses transferred to them. The interaction between the two systems preserves dynamic properties of the flowing platelets, such as the flipping motion. Using this multiscale particle-based approach, we have further studied the effects of the platelet elastic modulus by comparing the action of the flow-induced shear stresses on rigid and deformable platelet models. The results indicate that neglecting the platelet deformability may overestimate the stress on the platelet membrane, which in turn may lead to erroneous predictions of the platelet activation under viscous shear flow conditions. This particle-based fluid-structure interaction multiscale model offers for the first time a computationally feasible approach for simulating deformable platelets interacting with viscous blood flow, aimed at predicting flow induced platelet activation by using a highly resolved mapping of the stress distribution on the platelet membrane under dynamic flow conditions.
Collapse
|