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Biodegradable external wrapping promotes favorable adaptation in an ovine vein graft model. Acta Biomater 2022; 151:414-425. [PMID: 35995404 DOI: 10.1016/j.actbio.2022.08.029] [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: 03/24/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022]
Abstract
Vein grafts, the most commonly used conduits in multi-vessel coronary artery bypass grafting surgery, have high intermediate- and long-term failure rates. The abrupt and marked increase in hemodynamic loads on the vein graft is a known contributor to failure. Recent computational modeling suggests that veins can more successfully adapt to an increase in mechanical load if the rate of loading is gradual. Applying an external wrap or support at the time of surgery is one way to reduce the transmural load, and this approach has improved performance relative to an unsupported vein graft in several animal studies. Yet, a clinical trial in humans has shown benefits and drawbacks, and mechanisms by which an external wrap affects vein graft adaptation remain unknown. This study aims to elucidate such mechanisms using a multimodal experimental and computational data collection pipeline. We quantify morphometry using magnetic resonance imaging, mechanics using biaxial testing, hemodynamics using computational fluid dynamics, structure using histology, and transcriptional changes using bulk RNA-sequencing in an ovine carotid-jugular interposition vein graft model, without and with an external biodegradable wrap that allows loads to increase gradually. We show that a biodegradable external wrap promotes luminal uniformity, physiological wall shear stress, and a consistent vein graft phenotype, namely, it prevents over-distension, over-thickening, intimal hyperplasia, and inflammation, and it preserves mechanotransduction. These mechanobiological insights into vein graft adaptation in the presence of an external support can inform computational growth and remodeling models of external support and facilitate design and manufacturing of next-generation external wrapping devices. STATEMENT OF SIGNIFICANCE: External mechanical support is emerging as a promising technology to prevent vein graft failure following coronary bypass graft surgery. While variants of this technology are currently under investigation in clinical trials, the fundamental mechanisms of adaptation remain poorly understood. We employ an ovine carotid-jugular interposition vein graft model, with and without an external biodegradable wrap to provide mechanical support, and probe vein graft adaptation using a multimodal experimental and computational data collection pipeline. We quantify morphometry using magnetic resonance imaging, mechanics using biaxial testing, fluid flow using computational fluid dynamics, vascular composition and structure using histology, and transcriptional changes using bulk RNA sequencing. We show that the wrap mitigates vein graft failure by promoting multiple adaptive mechanisms (across biological scales).
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Zhao TY, Bu JQ, Gu JJ, Liu Y, Zhang WL, Chen ZY. The Short-Term Patency Rate of a Saphenous Vein Bridge Using the No-Touch Technique in off-Pump Coronary Artery Bypass Grafting in Vein Harvesting. Int J Gen Med 2021; 14:2281-2288. [PMID: 34113157 PMCID: PMC8184136 DOI: 10.2147/ijgm.s311249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/18/2021] [Indexed: 11/23/2022] Open
Abstract
Objective This study aimed to examine the short-term effect of the no-touch technique on the patency rate of a great saphenous vein (GSV) bridge used during off-pump coronary artery bypass grafting (OPCABG). Methods Between June 2018 and September 2020, 140 patients undergoing OPCABG, with grafts obtained from the GSV using the "no-touch" technique or the left internal mammary artery (LIMA), were enrolled in this study. The early clinical results and short-term patency rate of the OPCABG were evaluated at a three-month follow-up by comparing the patency rate of the LIMA bridge and the GSV bridge obtained by the no-touch technique. This study also analyzed the impacts of the postoperative complications of the lower limbs and the distribution area of diseased vessels on the patency rate of a GSV bridge obtained by the no-touch technique at an early stage. Results No perioperative death or adverse cardiovascular or cerebrovascular events occurred in the 140 patients undergoing OPCABG. The difference in the early patency rate between the GSV bridge obtained by the no-touch technique and the LIMA bridge was not statistically significant (95.9% vs 97.1%, p = 0.501). There was no significant difference in the patency rate between an end-to-side anastomosed venous bridge and a LIMA bridge (95.0% [248/261] vs 97.1% [136/140], p = 0.314). The overall patency rate of a no-touch vein bridge in the right coronary artery region was lower than it was in the left coronary artery region (93.8% [165/176] vs 97.9% [183/187], p = 0.049). Conclusion The no-touch technique may improve the early patency rate of a GSV bridge, and its effect is similar to that of a LIMA bridge.
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Affiliation(s)
- Teng-Yue Zhao
- Department of Cardiac Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
| | - Ji-Qiang Bu
- Department of Cardiac Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
| | - Jian-Jun Gu
- Department of Cardiac Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
| | - Yu Liu
- Department of Cardiac Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
| | - Wen-Li Zhang
- Department of Cardiac Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
| | - Zi-Ying Chen
- Department of Cardiac Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, 050000, People's Republic of China
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MAO BOYAN, ZHAO ZHOU, LI BAO, FENG YUE, FENG YILI, LIU YOUJUN. THE COMPARISON OF VENOUS SEQUENTIAL AND NORMAL GRAFT PATENCY BASED ON HEMODYNAMICS. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519419500805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background: In coronary artery bypass grafting (CABG), the patency of venous sequential graft remains controversial. Hemodynamic factors have been proved to be the important factors influencing graft patency. The objective of this study is to compare the patency of sequential grafts and normal grafts by hemodynamic environment. Methods: This study used a patient’s clinical data to construct a 0D/3D coupled multi-scale model, and used this model to calculate graft’s hemodynamics under two grafting methods. Meanwhile, CABG ideal models were constructed based on grafts’ flow data of 60 patients (63 normal grafts, 19 sequential grafts) to calculate grafts’ hemodynamics. Results: Based on the multi-scale model, it was found that the sequential graft flow and time average wall shear stress (TAWSS) were higher than normal graft, which was good for graft patency. But there were a flow separation region, some regions of high oscillatory shear index (OSI) and relative residence time (RRT) in sequential graft, which could lead to intimal hyperplasia. Based on ideal CABG models, it was known that failure rate of sequential and normal grafts were 36.8% and 36.5%, and there were significant differences between them in flow rate, TAWSS and OSI (sequential versus normal: flow rate (ml/min): [Formula: see text] versus [Formula: see text], TAWSS (Pa): [Formula: see text] versus [Formula: see text], OSI: 0.[Formula: see text] versus [Formula: see text]). Conclusion: For saphenous venous graft (SVG), although the normal graft has similar patency with the sequential graft, the hemodynamic mechanism behind it is different. In flow rate and WSS, sequential grafts have an advantage over normal grafts. But there are high OSI and RRT regions in sequential grafts.
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Affiliation(s)
- BOYAN MAO
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - ZHOU ZHAO
- Cardiac Surgery Department, PeKing University People’s Hospital, 11th South Ave. Xizhimen, Beijing, P. R. China
| | - BAO LI
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - YUE FENG
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - YILI FENG
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - YOUJUN LIU
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing, P. R. China
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Mao B, Feng Y, Wang W, Li B, Zhao Z, Zhang X, Jin C, Wu D, Liu Y. The influence of hemodynamics on graft patency prediction model based on support vector machine. J Biomech 2019; 98:109426. [PMID: 31677778 DOI: 10.1016/j.jbiomech.2019.109426] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 10/10/2019] [Accepted: 10/13/2019] [Indexed: 01/23/2023]
Abstract
In the existing patency prediction model of coronary artery bypass grafting (CABG), the characteristics are based on graft flow, but no researchers selected hemodynamic factors as the characteristics. The purpose of this paper is to study whether the introduction of hemodynamic factors will affect the performance of the prediction model. Transit time flow-meter (TTFM) waveforms and 1-year postoperative patency results were obtained from 50 internal mammary arterial grafts (LIMA) and 82 saphenous venous grafts (SVG) in 60 patients. Taking TTFM waveforms as the boundary conditions, the CABG ideal models were constructed to obtain hemodynamic factors in grafts. Based on clinical characteristics and combination of clinical and hemodynamic characteristics, patency prediction models based on support vector machine (SVM) were constructed respectively. For LIMA, after the introduction of hemodynamic factors, the accuracy, sensitivity and specificity of the prediction model increased from 70.35%, 50% and 74.17% to 78.02%, 70% and 78.89%, respectively. For SVG, the accuracy, sensitivity and specificity of the prediction model increased from 63.24%, 40% and 76.91% to 74.41%, 60.1% and 82.73%, respectively. The performance of the prediction model can be improved by introducing hemodynamic factors into the characteristics of the model. The accuracy, sensitivity and specificity of the prediction results are higher with the addition of hemodynamic characteristics.
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Affiliation(s)
- Boyan Mao
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Yue Feng
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Wenxin Wang
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China; Neusoft Medical System, Neusoft Beijing R&D Center, Zhongguancun Software Park 10, Xibeiwang East Road, Haidian District, Beijing 100194, China
| | - Bao Li
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Zhou Zhao
- Cardiac Surgery Department, PeKing University People's Hospital, 11th South Ave. Xizhimen, Beijing, China
| | - Xiaoyan Zhang
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Chunbo Jin
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Dandan Wu
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Youjun Liu
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China.
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Gooch KJ, Firstenberg MS, Shrefler BS, Scandling BW. Biomechanics and Mechanobiology of Saphenous Vein Grafts. J Biomech Eng 2019; 140:2666246. [PMID: 29222565 DOI: 10.1115/1.4038705] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Indexed: 11/08/2022]
Abstract
Within several weeks of use as coronary artery bypass grafts (CABG), saphenous veins (SV) exhibit significant intimal hyperplasia (IH). IH predisposes vessels to thrombosis and atherosclerosis, the two major modes of vein graft failure. The fact that SV do not develop significant IH in their native venous environment coupled with the rapidity with which they develop IH following grafting into the arterial circulation suggests that factors associated with the isolation and preparation of SV and/or differences between the venous and arterial environments contribute to disease progression. There is strong evidence suggesting that mechanical trauma associated with traditional techniques of SV preparation can significantly damage the vessel and might potentially reduce graft patency though modern surgical techniques reduces these injuries. In contrast, it seems possible that modern surgical technique, specifically endoscopic vein harvest, might introduce other mechanical trauma that could subtly injure the vein and perhaps contribute to the reduced patency observed in veins harvested using endoscopic techniques. Aspects of the arterial mechanical environment influence remodeling of SV grafted into the arterial circulation. Increased pressure likely leads to thickening of the medial wall but its role in IH is less clear. Changes in fluid flow, including increased average wall shear stress, may reduce IH while disturbed flow likely increase IH. Nonmechanical stimuli, such as exposure to arterial levels of oxygen, may also have a significant but not widely recognized role in IH. Several potentially promising approaches to alter the mechanical environment to improve graft patency are including extravascular supports or altered graft geometries are covered.
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Affiliation(s)
- Keith J Gooch
- Department of Biomedical Engineering, The Ohio State University, 290 Bevis Hall 1080 Carmack Drive, Columbus, OH 43210.,Davis Heart Lung Research Institute, The Ohio State University, Columbus, OH 43210 e-mail:
| | - Michael S Firstenberg
- Surgery and Integrative Medicine, Northeast Ohio Medical Universities, Akron, OH 44309
| | - Brittany S Shrefler
- Department of Internal Medicine, The Ohio State University, Columbus, OH 43210
| | - Benjamin W Scandling
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210
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Avrahami I, Raz D, Bash O. Biomechanical Aspects of Closing Approaches in Postcarotid Endarterectomy. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2018; 2018:4517652. [PMID: 30510592 PMCID: PMC6230422 DOI: 10.1155/2018/4517652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 08/25/2018] [Accepted: 09/17/2018] [Indexed: 11/30/2022]
Abstract
The carotid bifurcation tends to develop atherosclerotic stenoses which might interfere with cerebral blood supply. In cases of arterial blockage, the common clinical solution is to remove the plaque via carotid endarterectomy (CEA) surgery. Artery closure after surgery using primary closures along the cutting edge might lead to artery narrowing and restrict blood flow. An alternative approach is patch angioplasty which takes longer time and leads to more during-surgery complications. The present study uses numerical methods with fluid-structure interaction (FSI) to explore and compare the two solutions in terms of hemodynamics and stress and strain fields developed in the artery wall.
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Affiliation(s)
- Idit Avrahami
- Department of Mechanical Engineering and Mechatronics, Ariel University, Ariel, Israel
| | - Dafna Raz
- Department of Mechanical Engineering and Mechatronics, Ariel University, Ariel, Israel
| | - Oranit Bash
- Department of Mechanical Engineering and Mechatronics, Ariel University, Ariel, Israel
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Amin S, Werner RS, Madsen PL, Krasopoulos G, Taggart DP. Influence of external stenting on venous graft flow parameters in coronary artery bypass grafting: a randomized study. Interact Cardiovasc Thorac Surg 2018; 26:926-931. [DOI: 10.1093/icvts/ivy007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/30/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sanaz Amin
- Nuffield department of surgical sciences, University of Oxford, Oxford, UK
- Department of Cardiovascular Surgery, Oxford University Hospitals Trust, Oxford, UK
| | - Raphael S Werner
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Per Lav Madsen
- Department of Cardiology, Copenhagen University Hospital, Herlev, Denmark
| | - George Krasopoulos
- Nuffield department of surgical sciences, University of Oxford, Oxford, UK
- Department of Cardiovascular Surgery, Oxford University Hospitals Trust, Oxford, UK
| | - David P Taggart
- Nuffield department of surgical sciences, University of Oxford, Oxford, UK
- Department of Cardiovascular Surgery, Oxford University Hospitals Trust, Oxford, UK
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Chen Y, Deng X, Shan X, Xing Y. Study of helical flow inducers with different thread pitches and diameters in vena cava. PLoS One 2018; 13:e0190609. [PMID: 29298357 PMCID: PMC5752007 DOI: 10.1371/journal.pone.0190609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/18/2017] [Indexed: 11/25/2022] Open
Abstract
Pulmonary embolism is a severe, potentially life-threatening condition. Inferior vena cava filters have been used to prevent recurrent pulmonary embolisms. However, the build-up of thrombosis in vena cava filters after deployment presents a severe problem to patients. Previous studies proposed that filters with helical flow are beneficial and capable of alleviating this problem. In this study, the hemodynamic performances of four typical helical flow inducers in the vena cava are determined using computational fluid dynamics simulations (steady-state and pulsatile flow) and compared. Pilot in vitro experiments were also conducted. The simulation results demonstrate that large-diameter inducers produce helical flow. Among inducers with identical diameter, those with a smaller thread pitch are more likely to induce increased helical flow. We also observed that the small thread pitch inducers can yield higher shear rates. Furthermore, a large diameter, small thread pitch helical flow inducer increases the time-averaged wall shear stress and reduces the oscillating shear index and relative residence time on the vessel wall in the vicinity of the helical flow inducer. In vitro experiments also verify that large diameter inducers generate a helical flow. A notable observation of this study is that the diameter is the key parameter that affects the induction of a helical flow. This study will likely provide important guidance for the design of interventional treatments and the deployment of filters associated with helical flow in the vena cava.
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Affiliation(s)
- Ying Chen
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
- * E-mail:
| | - Xinying Shan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Yubin Xing
- Department of Infection Management and Disease Control, The General Hospital of People’s Liberation Army, Beijing, China
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Boire TC, Balikov DA, Lee Y, Guth CM, Cheung-Flynn J, Sung HJ. Biomaterial-Based Approaches to Address Vein Graft and Hemodialysis Access Failures. Macromol Rapid Commun 2016; 37:1860-1880. [PMID: 27673474 PMCID: PMC5156561 DOI: 10.1002/marc.201600412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/15/2016] [Indexed: 12/19/2022]
Abstract
Veins used as grafts in heart bypass or as access points in hemodialysis exhibit high failure rates, thereby causing significant morbidity and mortality for patients. Interventional or revisional surgeries required to correct these failures have been met with limited success and exorbitant costs, particularly for the US Centers for Medicare & Medicaid Services. Vein stenosis or occlusion leading to failure is primarily the result of neointimal hyperplasia. Systemic therapies have achieved little long-term success, indicating the need for more localized, sustained, biomaterial-based solutions. Numerous studies have demonstrated the ability of external stents to reduce neointimal hyperplasia. However, successful results from animal models have failed to translate to the clinic thus far, and no external stent is currently approved for use in the US to prevent vein graft or hemodialysis access failures. This review discusses current progress in the field, design considerations, and future perspectives for biomaterial-based external stents. More comparative studies iteratively modulating biomaterial and biomaterial-drug approaches are critical in addressing mechanistic knowledge gaps associated with external stent application to the arteriovenous environment. Addressing these gaps will ultimately lead to more viable solutions that prevent vein graft and hemodialysis access failures.
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Affiliation(s)
- Timothy C Boire
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
| | - Daniel A Balikov
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
| | - Yunki Lee
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
| | - Christy M Guth
- Division of Vascular Surgery, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Joyce Cheung-Flynn
- Division of Vascular Surgery, Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Hak-Joon Sung
- Department of Biomedical Engineering, Vanderbilt University, 37235, Nashville, TN, USA
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, 120-752, Republic of Korea
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