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Navaneeth Krishna RP, Jain A. In silico analyses of blood flow and oxygen transport in human micro-veins and valves. Clin Hemorheol Microcirc 2022; 81:81-96. [PMID: 35034895 DOI: 10.3233/ch-211345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Almost 95% of the venous valves are micron scale found in veins smaller than 300μm diameter. The fluid dynamics of blood flow and transport through these micro venous valves and their contribution to thrombosis is not yet well understood or characterized due to difficulty in making direct measurements in murine models. OBJECTIVE The unique flow patterns that may arise in physiological and pathological non-actuating micro venous valves are predicted. METHODS Computational fluid and transport simulations are used to model blood flow and oxygen gradients in a microfluidic vein. RESULTS The model successfully recreates the typical non-Newtonian vortical flow within the valve cusps seen in preclinical experimental models and in clinic. The analysis further reveals variation in the vortex strengths due to temporal changes in blood flow. The cusp oxygen is typically low from the main lumen, and it is regulated by systemic venous flow. CONCLUSIONS The analysis leads to a clinically-relevant hypothesis that micro venous valves may not create a hypoxic environment needed for endothelial inflammation, which is one of the main causes of thrombosis. However, incompetent micro venous valves are still locations for complex fluid dynamics of blood leading to low shear regions that may contribute to thrombosis through other pathways.
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Affiliation(s)
| | - Abhishek Jain
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, USA.,Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, USA.,Department of Cardiovascular Sciences, Houston Methodist Academic Institute, Houston, USA
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2
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Fernández-Colino A, Jockenhoevel S. Advances in Engineering Venous Valves: The Pursuit of a Definite Solution for Chronic Venous Disease. TISSUE ENGINEERING PART B-REVIEWS 2020; 27:253-265. [PMID: 32967586 DOI: 10.1089/ten.teb.2020.0131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Native venous valves enable proper return of blood to the heart. Under pathological conditions (e.g., chronic venous insufficiency), venous valves malfunction and fail to prevent backward flow. Clinically, this can result in painful swelling, varicose veins, edema, and skin ulcerations leading to a chronic wound situation. Surgical correction of venous valves has proven to drastically reduce these symptoms. However, the absence of intact leaflets in many patients limits the applicability of this strategy. In this context, the development of venous valve replacements represents an appealing approach. Despite acceptable results in animal models, no venous valve has succeeded in clinical trials, and so far no single prosthetic venous valve is commercially available. This calls for advanced materials and fabrication approaches to develop clinically relevant venous valves able to restore natural flow conditions in the venous circulation. In this study, we critically discuss the approaches attempted in the last years, and we highlight the potential of tissue engineering to offer new avenues for valve fabrication. Impact statement Venous valves prosthesis offer the potential to restore normal venous flow, and to improve the prospect of patients that suffer from chronic venous disease. Current venous valve replacements are associated with poor outcomes. A deeper understanding of the approaches attempted so far is essential to establish the next steps toward valve development, and importantly, tissue engineering constitutes a unique toolbox to advance in this quest.
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Affiliation(s)
- Alicia Fernández-Colino
- Department of Biohybrid & Medical Textiles (BioTex), AME-Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Stefan Jockenhoevel
- Department of Biohybrid & Medical Textiles (BioTex), AME-Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany.,AMIBM-Aachen-Maastricht-Institute for Biobased Materials, Maastricht University, Geleen, Netherlands
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3
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Zervides C, Mahdi H, Staub RA, Jouni H. Prosthetic venous valves: Short history and advancements from 2012 to 2020. Phlebology 2020; 36:174-183. [PMID: 33021138 DOI: 10.1177/0268355520962451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chronic Venous Disease is estimated at 83.6% of the global population. Patients experience pain, discomfort and severe complications with few effective therapies being available. Current strategies for the treatment of malfunctioning venous valves are invasive with a high recurrence rate. A prosthetic venous valve replacement is imminent, possibly providing better outcomes and improved general quality of life. In this review, prosthetic venous valves history is presented and assesses the advantages and disadvantages of developed venous valves. Articles that discussed potential designs of prosthetic venous valves were examined. A systematic search produced thirty-five papers fitting the inclusion criteria. Our understanding of the ideal abilities required in prosthetic valves has evolved. Developed valves are reported for regurgitation, migration and leakage. Issues have been resolved, but we are still away from the ideal valve. Improvements within the last eight years provided information on the importance of sinuses and prosthetic to venous wall-size mismatch.
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Affiliation(s)
| | - Habib Mahdi
- University of Nicosia Medical School, Nicosia, Cyprus
| | | | - Hassan Jouni
- University of Nicosia Medical School, Nicosia, Cyprus
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Hajati Z, Sadegh Moghanlou F, Vajdi M, Razavi SE, Matin S. Fluid-structure interaction of blood flow around a vein valve. BIOIMPACTS 2020; 10:169-175. [PMID: 32793439 PMCID: PMC7416012 DOI: 10.34172/bi.2020.21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 11/09/2019] [Accepted: 12/14/2019] [Indexed: 11/09/2022]
Abstract
Introduction: Venous valves are a type of one-way valves which conduct blood flow toward the heart and prevent its backflow. Any malfunction of these organs may cause serious problems in the circulatory system. Numerical simulation can give us detailed information and point to point data such as velocity, wall shear stress, and von Mises stress from veins with small diameters, as obtaining such data is almost impossible using current medical devices. Having detailed information about fluid flow and valves' function can help the treatment of the related diseases. Methods: In the present work, the blood flow through a venous valve considering the flexibility of the vein wall and valve leaflets is investigated numerically. The governing equations of fluid flow and solid domain are discretized and solved by the Galerkin finite element method. Results: The obtained results showed that the blood velocity increases from inlet to the leaflets and then decreases passing behind the valve. A pair of vortices and the trapped region was observed just behind the valves. These regions have low shear stresses and are capable of sediment formation. Conclusion: The von Mises stress which is a criterion for the breakdown of solid materials was obtained. It was also observed that a maximum value occurred at the bottom of the leaflets.
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Affiliation(s)
- Zahra Hajati
- Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
| | | | - Mohammad Vajdi
- Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
| | | | - Somaieh Matin
- Department of Internal Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
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5
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Tissue-engineered transcatheter vein valve. Biomaterials 2019; 216:119229. [DOI: 10.1016/j.biomaterials.2019.119229] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 05/14/2019] [Accepted: 05/25/2019] [Indexed: 01/31/2023]
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6
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Easson G, Laughlin M, Jensen H, Haney K, Girardot M, Jensen M. Performance changes of venous valves following tissue treatment with novel in vitro system. Phlebology 2019; 34:347-354. [PMID: 30336758 DOI: 10.1177/0268355518804360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The purpose of this study is to test venous valve performance and identify differences between native tissue and replacement devices developed with traditional tissue treatment methods using a new in vitro model with synchronized hemodynamic parameters and high-speed valve image acquisition. METHODS An in vitro model mimicking the venous circulation to test valve performance was developed using hydrostatic pressure driven flow. Fresh and glutaraldehyde-treated vein segments were placed in the setup and opening/closing of the valves was captured by a high-speed camera. Hemodynamic data were obtained using synchronized hardware and virtual instrumentation. RESULTS Geometric orifice area and opening/closing time of the valves was evaluated at the same hemodynamic conditions. A reduction in geometric orifice area of 27.2 ± 14.8% (p < 0.05) was observed following glutaraldehyde fixation. No significant difference in opening/closing time following chemical fixation was observed. CONCLUSIONS The developed in vitro model was shown to be an effective method for measuring the performance of venous valves. The observed decrease in geometric orifice area following glutaraldehyde treatment indicates a decrease in flow through the valve, demonstrating the consequences of traditional tissue treatment methods.
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Affiliation(s)
- Garrett Easson
- 1 Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Megan Laughlin
- 1 Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Hanna Jensen
- 1 Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Kevin Haney
- 2 Ozark Regional Vein Center, Rogers, AR, USA
| | | | - Morten Jensen
- 1 Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
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Chen HY, Tien WS, Chambers SD, Dabiri D, Kassab GS. Search for an Optimal Design of a Bioprosthetic Venous Valve: In silico and in vitro Studies. Eur J Vasc Endovasc Surg 2019; 58:112-119. [PMID: 31133446 DOI: 10.1016/j.ejvs.2018.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 12/05/2018] [Indexed: 11/16/2022]
Abstract
OBJECTIVE/BACKGROUND Valve incompetence is a progressive disease of the venous system that may eventually lead to venous hypertension, pain, and ulcers. There is a need for a venous valve prosthesis to replace incompetent valves. Computational and experimental investigations on venous valve design and associated haemodynamics will undoubtedly advance prosthesis design and treatments. Here, the objective is to investigate the effect of venous valve on the fluid and solid mechanics. The hypothesis is that there exists a valve geometry that maximises leaflet shear stress (LSS) but minimises leaflet intramural stress (LIS; i.e., minimise stress ratio = LIS/LSS). METHODS To address the hypothesis, fully dynamic fluid-structure interaction (FSI) models were developed. The entire cycle of valve opening and closure was simulated. The flow validation experiments were conducted using a stented venous valve prosthesis and a pulse duplicator flow loop. RESULTS Agreement between the output of FSI simulations and output of pulse duplicator was confirmed. The maximum flow rates were within 6% difference, and the total flow during the cycle was within 10% difference. The simulated high stress ratio region at the leaflet base (five times the leaflet average) predicted the disease location of the vast majority of explanted venous valves reported in clinical literature. The study found that the reduced valve height and leaflet dome shape resulted in optimal performance to provide the lowest stress ratio. CONCLUSION This study proposes an effective design of venous prostheses and elaborates on the correlations of venous valve with clinical observations.
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Affiliation(s)
- Henry Y Chen
- California Medical Innovations Institute, San Diego, CA, USA
| | - Wei-Shin Tien
- Department of Biomedical Engineering, University of Washington, Seattle, WA, USA
| | | | - Dana Dabiri
- Department of Biomedical Engineering, University of Washington, Seattle, WA, USA
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Soifer E, Weiss D, Marom G, Einav S. The effect of pathologic venous valve on neighboring valves: fluid-structure interactions modeling. Med Biol Eng Comput 2016; 55:991-999. [PMID: 27663560 DOI: 10.1007/s11517-016-1575-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 09/15/2016] [Indexed: 11/27/2022]
Abstract
Understanding the hemodynamics surrounding the venous valve environment is of a great importance for prosthetic valves design. The present study aims to evaluate the effect of leaflets' stiffening process on the venous valve hemodynamics, valve's failure on the next proximal valve hemodynamics and valve's failure in a secondary daughter vein on the healthy valve hemodynamics in the main vein when both of these valves are distal to a venous junction. Fully coupled, two-way fluid-structure interaction computational models were developed and employed. The sinus pocket region experiences the lowest fluid shear stress, and the base region of the sinus side of the leaflet experiences the highest tissue stress. The leaflets' stiffening increases the tissue stress the valve is experiencing in a very low fluid shear region. A similar effect occurs with the proximal healthy valve as a consequence of the distal valve's failure and with the mother vein valve as a consequence of daughter vein valve's failure. Understanding the described mechanisms may be helpful for elucidating the venous valve stiffness-function relationship in nature, the reasons for a retrograde development of reflux and the relationship between venous valves located near venous junctions, and for designing better prosthetic valves and for improving their positioning.
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Affiliation(s)
- Elina Soifer
- The Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel.
| | - Dar Weiss
- The Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel
| | - Gil Marom
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Shmuel Einav
- The Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel.,Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
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Kuna VK, Rosales A, Hisdal J, Osnes EK, Sundhagen JO, Bäckdahl H, Sumitran-Holgersson S, Jørgensen JJ. Successful tissue engineering of competent allogeneic venous valves. J Vasc Surg Venous Lymphat Disord 2015; 3:421-430.e1. [PMID: 26992620 DOI: 10.1016/j.jvsv.2014.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 12/22/2014] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate whether tissue-engineered human allogeneic vein valves have a normal closure time (competency) and tolerate reflux pressure in vitro. METHODS Fifteen human allogeneic femoral vein segments containing valves were harvested from cadavers. Valve closure time and resistance to reflux pressure (100 mm Hg) were assessed in an in vitro model to verify competency of the vein valves. The segments were tissue engineered using the technology of decellularization (DC) and recellularization (RC). The decellularized and recellularized vein segments were characterized biochemically, immunohistochemically, and biomechanically. RESULTS Four of 15 veins with valves were found to be incompetent immediately after harvest. In total, 2 of 4 segments with incompetent valves and 10 of 11 segments with competent valves were further decellularized using detergents and DNAse. DC resulted in significant decrease in host DNA compared with controls. DC scaffolds, however, retained major extracellular matrix proteins and mechanical integrity. RC resulted in successful repopulation of the lumen and valves of the scaffold with endothelial and smooth muscle cells. Valve mechanical parameters were similar to the native tissue even after DC. Eight of 10 veins with competent valves remained competent even after DC and RC, whereas the two incompetent valves remained incompetent even after DC and RC. The valve closure time to reflux pressure of the tissue-engineered veins was <0.5 second. CONCLUSIONS Tissue-engineered veins with valves provide a valid template for future preclinical studies and eventual clinical applications. This technique may enable replacement of diseased incompetent or damaged deep veins to treat axial reflux and thus reduce ambulatory venous hypertension.
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Affiliation(s)
- Vijay Kumar Kuna
- Laboratory for Transplantation and Regenerative Medicine, Department of Surgery, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Antonio Rosales
- Department of Vascular Surgery, Oslo Vascular Centre, Oslo University Hospital, Aker, Norway
| | - Jonny Hisdal
- Department of Vascular Surgery, Oslo Vascular Centre, Oslo University Hospital, Aker, Norway
| | - Eivind K Osnes
- Department of Vascular Surgery, Oslo Vascular Centre, Oslo University Hospital, Aker, Norway
| | - Jon O Sundhagen
- Department of Vascular Surgery, Oslo Vascular Centre, Oslo University Hospital, Aker, Norway
| | - Henrik Bäckdahl
- Department of Chemistry, Materials, and Surfaces, SP Technical Research Institute of Sweden, Borås, Sweden
| | - Suchitra Sumitran-Holgersson
- Laboratory for Transplantation and Regenerative Medicine, Department of Surgery, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
| | - Jørgen J Jørgensen
- Department of Vascular Surgery, Oslo Vascular Centre, Oslo University Hospital, Aker, Norway; Vascular Department, University of Oslo, Oslo, Norway
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Characterization of a Bioprosthetic Bicuspid Venous Valve Hemodynamics: Implications for Mechanism of Valve Dynamics. Eur J Vasc Endovasc Surg 2014; 48:459-64. [DOI: 10.1016/j.ejvs.2014.06.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 06/07/2014] [Indexed: 11/24/2022]
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