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Shah I, Molony D, Lefieux A, Crawford K, Piccinelli M, Sun H, Giddens D, Samady H, Veneziani A. Impact of the stent footprint on endothelial wall shear stress in patient-specific coronary arteries: A computational analysis from the SHEAR-STENT trial. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2025; 266:108762. [PMID: 40245606 DOI: 10.1016/j.cmpb.2025.108762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2024] [Revised: 03/07/2025] [Accepted: 03/31/2025] [Indexed: 04/19/2025]
Abstract
BACKGROUND AND OBJECTIVE Wall shear stress (WSS) has been known to play a critical role in the development of several complications following coronary artery stenting, including in-stent restenosis and thrombosis. Computational fluid dynamics is often used to quantify the post-stenting WSS, which may potentially be used as a predictive metric. However, large-scale studies for WSS-based risk stratification often neglect the footprint of the stent due to reconstruction challenges. The primary objective of this study is to statistically evaluate the impact of the stent footprints (Xience and Resolute stents) on the computed endothelial WSS and quantitatively identify the relationship between these local hemodynamic alterations and the global properties of the vessel, such as curvature, on WSS. The ultimate goal is to evaluate whether and when it is worth including the footprint of the stent in an in-silico study to compute the WSS reliably. METHODS A previously developed semi-automated reconstruction approach for patient-specific coronaries was employed as a part of the SHEAR-STENT trial. A subset of patients was analyzed (N=30), and CFD simulations were performed with and without the stent to evaluate the impact of the stent footprint on WSS. Due to the computationally expensive nature of transient analyses, a sub-cohort of ten patients were used to assess the reliability of WSS obtained from steady computations as a surrogate for the time-averaged results. Global and local vessel curvature data were extracted for all cases and evaluated against stent-induced alterations in the WSS. The differences between the Xience and Resolute stent platforms were also examined to quantify each stent's unique WSS footprint. RESULTS Results from the surrogate analysis indicate that steady WSS serves as an excellent approximation of the time-averaged computations. The presence of either stent footprint causes a statistically significant decrease in the space-averaged WSS, and a significant increase in the endothelial regions exposed to very low WSS as well (<0.5 Pa). Negative correlations were observed between vessel curvature and WSS differences, indicating that macroscopic vessel characteristics play a more prominent role in determining endothelial WSS at higher curvature values. In our pool of cases, comparison of Xience and Resolute stents revealed that the Resolute platform seems to lead to lower space-averaged WSS and an increase in areas of very low WSS. CONCLUSION These results outline (1) the necessity of including the stent footprint for accurate in-silico WSS analysis; (2) the global features of stented arteries serving as the dominant determinant of WSS past a certain curvature threshold; and (3) the Xience stent resulting in a milder presence of hemodynamically unfavorable WSS regions compared to the Resolute stent.
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Affiliation(s)
- Imran Shah
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Nerem Street NW, Atlanta, GA 30313, USA; Department of Mathematics, Emory University, 400 Dowman Drive, Atlanta, GA 30322, USA.
| | - David Molony
- Georgia Heart Institute, Northeast Georgia Medical Center, 200 South Enota Drive, Gainseville, GA 30501, USA
| | - Adrien Lefieux
- Georgia Heart Institute, Northeast Georgia Medical Center, 200 South Enota Drive, Gainseville, GA 30501, USA
| | - Kaylyn Crawford
- Georgia Heart Institute, Northeast Georgia Medical Center, 200 South Enota Drive, Gainseville, GA 30501, USA
| | - Marina Piccinelli
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, 100 Woodruff Circle, Atlanta, GA 30322, USA
| | - Hanyao Sun
- AU/UGA Medical Partnership, Medical College of Georgia, Prince Avenue, Athens, GA 30602, USA
| | - Don Giddens
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 387 Nerem Street NW, Atlanta, GA 30313, USA; Department of Medicine, Emory University School of Medicine, 100 Woodruff Circle, Atlanta, GA 30322, USA
| | - Habib Samady
- Georgia Heart Institute, Northeast Georgia Medical Center, 200 South Enota Drive, Gainseville, GA 30501, USA; Department of Medicine, Emory University School of Medicine, 100 Woodruff Circle, Atlanta, GA 30322, USA
| | - Alessandro Veneziani
- Department of Mathematics, Emory University, 400 Dowman Drive, Atlanta, GA 30322, USA; Department of Computer Science, Emory University, 400 Dowman Drive, Atlanta, GA 30322, USA
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Ahadi F, Azadi M, Biglari M, Bodaghi M. Topology optimization of coronary artery stent considering structural and hemodynamic parameters. Heliyon 2024; 10:e39452. [PMID: 39469694 PMCID: PMC11513526 DOI: 10.1016/j.heliyon.2024.e39452] [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: 07/26/2024] [Revised: 10/15/2024] [Accepted: 10/15/2024] [Indexed: 10/30/2024] Open
Abstract
In the present study, the impact of geometric variables and structural features of stents on hemodynamic parameters is investigated. Intravascular stent implantation is a treatment method whose success largely depends on the geometric structure of the stent and its effect on hemodynamic parameters. Medical devices called stents are inserted into arteries to restore blood flow when an artery is blocked. In this research, an optimal stent was designed and its effect compared to the common commercial stent used for coronary arteries was investigated and compared. It has been found that the geometry of the stent has an effective impact on the wall shear stress in the stented artery. Therefore, in this article, the importance of stent structures in the treatment of the coronary artery disease is discussed. For this purpose, first, an optimal stent is created with the topology optimization technique to find the best structure in the stent design. Finally, the optimized stent is numerically verified with ANSYS software and compared with existing commercial stents, and then the prototype is fabricated using additive manufacturing techniques. Commercial software ABAQUS, SolidWorks, and ANSYS are used in this research. The results showed that in optimizing a square plate, a sample with a minimum residual volume limit equal to 10 and 7 % can be selected as the optimal state. The results indicate that the new design can improve the distribution of wall shear stresses to reduce the adverse hemodynamic changes. Therefore, the proposed stent geometric structure can help improve the treatment. Finally, the optimized stent along with a commercial stent was made with the 3D printing method.
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Affiliation(s)
- Fatemeh Ahadi
- Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
| | - Mohammad Azadi
- Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
| | - Mojtaba Biglari
- Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
| | - Mahdi Bodaghi
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
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Qi W, Ooi A, Grayden DB, Opie NL, John SE. Haemodynamics of stent-mounted neural interfaces in tapered and deformed blood vessels. Sci Rep 2024; 14:7212. [PMID: 38532013 DOI: 10.1038/s41598-024-57460-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 03/18/2024] [Indexed: 03/28/2024] Open
Abstract
The endovascular neural interface provides an appealing minimally invasive alternative to invasive brain electrodes for recording and stimulation. However, stents placed in blood vessels have long been known to affect blood flow (haemodynamics) and lead to neointimal growth within the blood vessel. Both the stent elements (struts and electrodes) and blood vessel wall geometries can affect the mechanical environment on the blood vessel wall, which could lead to unfavourable vascular remodelling after stent placement. With increasing applications of stents and stent-like neural interfaces in venous blood vessels in the brain, it is necessary to understand how stents affect blood flow and tissue growth in veins. We explored the haemodynamics of a stent-mounted neural interface in a blood vessel model. Results indicated that blood vessel deformation and tapering caused a substantial change to the lumen geometry and the haemodynamics. The neointimal proliferation was evaluated in sheep implanted with an endovascular neural interface. Analysis showed a negative correlation with the mean Wall Shear Stress pattern. The results presented here indicate that the optimal stent oversizing ratio must be considered to minimise the haemodynamic impact of stenting.
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Affiliation(s)
- Weijie Qi
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Australia.
| | - Andrew Ooi
- Department of Mechanical Engineering, The University of Melbourne, Parkville, Australia
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Australia
- Graeme Clark Institute, The University of Melbourne, Parkville, Australia
| | - Nicholas L Opie
- Vascular Bionics Laboratory, Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Sam E John
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Australia
- Graeme Clark Institute, The University of Melbourne, Parkville, Australia
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
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4
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Hu J, Feng H, Zheng Y, Wang K, Wang X, Su J. Mechanism of effect of stenting on hemodynamics at iliac vein bifurcation. Comput Biol Med 2024; 170:107968. [PMID: 38244472 DOI: 10.1016/j.compbiomed.2024.107968] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 01/01/2024] [Accepted: 01/02/2024] [Indexed: 01/22/2024]
Abstract
When performing stent intervention for iliac vein compression syndrome, the operator selects the appropriate stent and determines its implantation depth according to the type and severity of iliac vein stenosis in the patient. However, there is still uncertainty regarding how the structure of the stent and its implantation depth affect hemodynamics at the site of lesion. In this paper, we analyzed three commonly used stents (Vena stent from Venmedtch, Venovo from Bard, and Smart stent from Cordis) with different implantation depths (0, 10, 20 mm) using computational fluid dynamics (CFD). We focused on evaluating hemorheological parameters such as time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), etc., within one pulsatile cycle after stent implantation. The correlation between geometric parameters of the stents and hemodynamic indicators was assessed using Pearson correlation coefficient (r), which was further validated through PIV velocity measurement experiment. The results revealed that an increase in implantation depth led to a more pronounced disturbance effect on blood flow at bifurcation for densely arranged support body-type stents. This effect was particularly significant during periods of smooth blood flow. On the other hand, crown-shaped Vena stents exhibited relatively less disruption to blood flow post-implantation. Implantation depth showed a strong negative correlation with TAWSS but a strong positive correlation with OSI and RRT. These findings suggest an increased risk of thrombosis at iliac vein bifurcation following stent placement. Amongst all three tested stents, Vena Stent demonstrated more favorable periodic parameters after implantation compared to others. These results provide valuable theoretical insights into understanding contralateral circulation thrombosis associated with iliac vein stenting.
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Affiliation(s)
- Jinming Hu
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot, 010000, PR China
| | - Haiquan Feng
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot, 010000, PR China.
| | - Yilin Zheng
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot, 010000, PR China
| | - Kun Wang
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot, 010000, PR China
| | - Xiaotian Wang
- The First Affiliated Hospital of University of Science and Technology of China, Hefei, PR China
| | - Juan Su
- School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot, 010051, PR China.
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5
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Schmidt W, Brandt-Wunderlich C, Behrens P, Kopetsch C, Schmitz KP, Andresen JR, Grabow N. Revisiting SFA stent technology: an updated overview on mechanical stent performance. BIOMED ENG-BIOMED TE 2023; 68:523-535. [PMID: 37183602 DOI: 10.1515/bmt-2022-0412] [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: 10/21/2022] [Accepted: 04/28/2023] [Indexed: 05/16/2023]
Abstract
OBJECTIVES The study investigated mechanical parameters of stent systems indicated for treatment of femoropopliteal (FP) arterial disease to support interpretation of clinical results and the related causalities. METHODS Eight stent system types of same dimensions were investigated (n=2). Parameters were the profile of stent delivery system (SDS), radiopacity, trackability and pushability, bending stiffness (flexibility) and axial stiffness of expanded stents, length change during expansion, radial force, crush resistance, strut thickness and general surface condition. RESULTS The trackability ranged from 0.237 to 0.920 N and the pushability was 47.9-67.6 %. The bending stiffness of SDS was between 108.42 and 412.68 N mm2. The length change during stent release to 5 mm was low, with one exception. The bending stiffness of the expanded stents was 2.73-41.67 N mm2. The normalized radial forces at 5 mm diameter ranged from 0.133 N/mm to 0.503 N/mm. During non-radial compression by 50 %, the forces were 3.07-8.42 N, with one exception (58.7 N). The strut thickness was 153-231 µm. CONCLUSIONS Large differences occurred for flexibility, radial force and length change during expansion. The data should be used when choosing the proper device for restoring vascular function.
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Affiliation(s)
- Wolfram Schmidt
- University Medical Center Rostock, Institute for Biomedical Engineering, Friedrich-Barnewitz-Str. 4, Rostock, 18119, Germany
| | | | - Peter Behrens
- Institute for ImplantTechnology and Biomaterials - IIB e.V., Rostock-Warnemuende, Germany
| | - Christoph Kopetsch
- Westkustenklinikum Heide, Institute of Diagnostic and Interventional Radiology/Neuroradiology, Heide, Schleswig-Holstein, Germany
| | - Klaus-Peter Schmitz
- Institute for ImplantTechnology and Biomaterials - IIB e.V., Rostock-Warnemuende, Germany
| | | | - Niels Grabow
- University Medical Center Rostock, Institute for Biomedical Engineering, Rostock, Germany
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Zuin M, Chatzizisis YS, Beier S, Shen C, Colombo A, Rigatelli G. Role of secondary flows in coronary artery bifurcations before and after stenting: What is known so far? CARDIOVASCULAR REVASCULARIZATION MEDICINE 2023; 55:83-87. [PMID: 37385893 DOI: 10.1016/j.carrev.2023.06.018] [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: 05/13/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/01/2023]
Abstract
Coronary arteries are uniformly exposed to traditional cardiovascular risk factors. However, atherosclerotic lesions occur in preferential regions of the coronary tree, especially in areas with disturbed local blood flow, such as coronary bifurcations. Over the latest years, secondary flows have been linked to the inception and progression of atherosclerosis. Most of these novel findings have been obtained in the field of computational fluid dynamic (CFD) analysis and biomechanics but remain poorly understood by cardiovascular interventionalists, despite the important impact that they may have in clinical practice. We aimed to summarize the current available data regarding the pathophysiological role of secondary flows in coronary artery bifurcation, providing an interpretation of these findings from an interventional perspective.
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Affiliation(s)
- Marco Zuin
- Department of Translational Medicine, University of Ferrara, Ferrara, Italy.
| | | | - Susann Beier
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW 2053, Australia
| | - Chi Shen
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW 2053, Australia
| | - Andrea Colombo
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW 2053, Australia
| | - Gianluca Rigatelli
- Interventional Cardiology, Department of Cardiology, Aulss6 Euganea, Ospedali Riuniti Padova Sud, Monselice, Italy
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7
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Feng H, Li C, Feng H. Numerical simulation and in vitro experimental study of thrombus capture efficiency of a new retrievable vena cava filter. Comput Methods Biomech Biomed Engin 2023; 26:2034-2046. [PMID: 36625716 DOI: 10.1080/10255842.2022.2163849] [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: 10/21/2022] [Revised: 12/20/2022] [Accepted: 12/26/2022] [Indexed: 01/11/2023]
Abstract
The vena cava filter is a filtering device to prevent pulmonary embolism caused by thrombosis from lower limbs and pelvis. A new retrievable vena cava filter was evaluated in this paper. To evaluate the hemodynamic performance and thrombus capture efficiency after transplantation, numerical simulation of computational fluid dynamics was performed. In this paper, the two-phase flow model of computational fluid dynamics software was used to analyze the outlet blood flow velocity, inlet-outlet pressure difference, filter wall shear stress, the ratio of area with wall shear stress, and the thrombus capture efficiency with the thrombus diameter of 5 mm, 10 mm, 15 mm and the thrombus content of 10%, 20%, 30%, respectively. Additionally, in vitro experimental test was performed to compare its thrombus capture efficiency with Denali and Aegisy Filters. The Denali Filter showed the least interference with the blood flow, followed by the new filter and the Aegisy Filter. The results indicated that the new filter had a higher capture rate in capturing 5mm small-diameter thrombus. This research certain theoretical significance and reference value for the research and development of the new vena cava filters as well as the evaluation of the thrombus capture efficiency of the filters.
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Affiliation(s)
- Haiquan Feng
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot, P.R. China
| | - Changsheng Li
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot, P.R. China
| | - Haoxiang Feng
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, P.R. China
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8
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Liu W, Wang X, Feng Y. Restoring endothelial function: shedding light on cardiovascular stent development. Biomater Sci 2023. [PMID: 37161519 DOI: 10.1039/d3bm00390f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Complete endothelialization is highly important for maintaining long-term patency and avoiding subsequent complications in implanting cardiovascular stents. It not only refers to endothelial cells (ECs) fully covering the inserted stents, but also includes the newly formed endothelium, which could exert physiological functions, such as anti-thrombosis and anti-stenosis. Clinical outcomes have indicated that endothelial dysfunction, especially the insufficiency of antithrombotic and barrier functions, is responsible for stent failure. Learning from vascular pathophysiology, endothelial dysfunction on stents is closely linked to the microenvironment of ECs. Evidence points to inflammatory responses, oxidative stress, altered hemodynamic shear stress, and impaired endothelial barrier affecting the normal growth of ECs, which are the four major causes of endothelial dysfunction. The related molecular mechanisms and efforts dedicated to improving the endothelial function are emphasized in this review. From the perspective of endothelial function, the design principles, advantages, and disadvantages behind current stents are introduced to enlighten the development of new-generation stents, aiming to offer new alternatives for restoring endothelial function.
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Affiliation(s)
- Wen Liu
- School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Tianjin 300350, P. R. China.
- Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin), Weijin Road 92, Tianjin 300072, P. R. China
| | - Xiaoyu Wang
- School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Tianjin 300350, P. R. China.
- Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin), Weijin Road 92, Tianjin 300072, P. R. China
| | - Yakai Feng
- School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Tianjin 300350, P. R. China.
- Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin), Weijin Road 92, Tianjin 300072, P. R. China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Weijin Road 92, Tianjin 300072, P. R. China
- Frontiers Science Center for Synthetic Biology, Tianjin University, Weijin Road 92, Tianjin 300072, China
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9
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Gregory DA, Fricker ATR, Mitrev P, Ray M, Asare E, Sim D, Larpnimitchai S, Zhang Z, Ma J, Tetali SSV, Roy I. Additive Manufacturing of Polyhydroxyalkanoate-Based Blends Using Fused Deposition Modelling for the Development of Biomedical Devices. J Funct Biomater 2023; 14:jfb14010040. [PMID: 36662087 PMCID: PMC9865795 DOI: 10.3390/jfb14010040] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/26/2022] [Accepted: 12/30/2022] [Indexed: 01/12/2023] Open
Abstract
In the last few decades Additive Manufacturing has advanced and is becoming important for biomedical applications. In this study we look at a variety of biomedical devices including, bone implants, tooth implants, osteochondral tissue repair patches, general tissue repair patches, nerve guidance conduits (NGCs) and coronary artery stents to which fused deposition modelling (FDM) can be applied. We have proposed CAD designs for these devices and employed a cost-effective 3D printer to fabricate proof-of-concept prototypes. We highlight issues with current CAD design and slicing and suggest optimisations of more complex designs targeted towards biomedical applications. We demonstrate the ability to print patient specific implants from real CT scans and reconstruct missing structures by means of mirroring and mesh mixing. A blend of Polyhydroxyalkanoates (PHAs), a family of biocompatible and bioresorbable natural polymers and Poly(L-lactic acid) (PLLA), a known bioresorbable medical polymer is used. Our characterisation of the PLA/PHA filament suggest that its tensile properties might be useful to applications such as stents, NGCs, and bone scaffolds. In addition to this, the proof-of-concept work for other applications shows that FDM is very useful for a large variety of other soft tissue applications, however other more elastomeric MCL-PHAs need to be used.
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10
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Qu Z, Wei H, Du T, Qiao A. Computational simulation of stent thrombosis induced by various degrees of stent malapposition. Front Bioeng Biotechnol 2022; 10:1062529. [PMID: 36452211 PMCID: PMC9701824 DOI: 10.3389/fbioe.2022.1062529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 10/31/2022] [Indexed: 07/02/2024] Open
Abstract
Percutaneous coronary intervention with stent implantation is one of the most commonly used approaches to treat coronary artery stenosis. Stent malapposition (SM) can increase the incidence of stent thrombosis, but the quantitative association between SM distance and stent thrombosis is poorly clarified. The objective of this study is to determine the biomechanical reaction mechanisms underlying stent thrombosis induced by SM and to quantify the effect of different SM severity grades on thrombosis. The thrombus simulation was performed in a continuous model based on the diffusion-convection response of blood substance transport. Simulated models included well-apposed stents and malapposed stents with various severities where the detachment distances ranged from 0 to 400 μm. The abnormal shear stress induced by SM was considered a critical contributor affecting stent thrombosis, which was dependent on changing SM distances in the simulation. The results illustrate that the proportion of thrombus volume was 1.88% at a SM distance of 75 μm (mild), 3.46% at 150 μm, and 3.93% at 400 μm (severe), but that a slight drop (3.18%) appeared at the detachment distance of 225 μm (intermediate). The results indicate that when the SM distance was less than 150 μm, the thrombus rose notably as the gap distance increased, whereas the progression of thrombogenicity weakened when it exceeded 150 μm. Therefore, more attention should be paid when SM is present at a gap distance of 150 μm. Moreover, when the SM length of stents are the same, thrombus tends to accumulate downstream towards the distal end of the stent as the SM distance increases.
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Affiliation(s)
| | | | | | - Aike Qiao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
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11
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Gharleghi R, Chen N, Sowmya A, Beier S. Towards automated coronary artery segmentation: A systematic review. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 225:107015. [PMID: 35914439 DOI: 10.1016/j.cmpb.2022.107015] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 07/03/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Vessel segmentation is the first processing stage of 3D medical images for both clinical and research use. Current segmentation methods are tedious and time consuming, requiring significant manual correction and hence are infeasible to use in large data sets. METHODS Here, we review and analyse available coronary artery segmentation methods, focusing on fully automated methods capable of handling the rapidly growing medical images available. All manuscripts published since 2010 are systematically reviewed, categorised into different groups based on the approach taken, and characteristics of the different approaches as well as trends over the past decade are explored. RESULTS The manuscripts were divided intro three broad categories, consisting of region growing, voxelwise prediction and partitioning approaches. The most common approach overall was region growing, particularly using active contour models, however these have had a sharp fall in popularity in recent years with convolutional neural networks becoming significantly more popular. CONCLUSIONS The systematic review of current coronary artery segmentation methods shows interesting trends, with rising popularity of machine learning methods, a focus on efficient methods, and falling popularity of computationally expensive processing steps such as vesselness and multiplanar reformation.
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Affiliation(s)
- Ramtin Gharleghi
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney NSW 2053, Australia.
| | - Nanway Chen
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney NSW 2053, Australia
| | - Arcot Sowmya
- School of Computer Science and Engineering, UNSW, Sydney NSW 2053, Australia; Tyree Foundation Institute of Health Engineering (Tyree IHealthE), Sydney, Australia
| | - Susann Beier
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney NSW 2053, Australia
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12
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Finite Element Analysis of Fluid–Structure Interaction in a Model of an L-Type Mg Alloy Stent-Stenosed Coronary Artery System. METALS 2022. [DOI: 10.3390/met12071176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The coronary stent deployment and subsequent service process is a complex geometric/physical nonlinear and fluid–structure coupling system. Analyzing the distribution of stress–strain on the stent is of great significance in studying the deformation and failure behavior. A coupled system dynamics model comprising stenotic coronary artery vessels and L-type Mg alloy stents was established by applying the polynomial hyperelastic constitutive theory. The nonlinear, significant deformation behavior of the stent was systematically studied. The stress–strain distribution of the coupling system during stent deployment was analyzed. The simulation results show that the edges of the supporting body fixed without a bridge are the weakest zone. The stress changes on the inside of the wave of the supporting body are very large, and the residual stress accumulated in this area is the highest. The peak stress of the plaque and the arterial wall was lower than the damage threshold. The velocity of the blood between the wave crest of the supporting body is large and the streamline distribution is concentrated. In addition, the inner surface pressure on the stent is evenly distributed along its axial dimension. The maximum arterial wall shear stress always appears on the inside of the wave crest of the supporting body fixed with a bridge, and, as such, the largest obstacle to the blood flow is in this zone.
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13
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Abbasnezhad N, Zirak N, Champmartin S, Shirinbayan M, Bakir F. An Overview of In Vitro Drug Release Methods for Drug-Eluting Stents. Polymers (Basel) 2022; 14:2751. [PMID: 35808798 PMCID: PMC9269075 DOI: 10.3390/polym14132751] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/15/2022] [Accepted: 06/16/2022] [Indexed: 01/08/2023] Open
Abstract
The drug release profile of drug-eluting stents (DESs) is affected by a number of factors, including the formulation, design, and physicochemical properties of the utilized material. DES has been around for twenty years and despite its widespread clinical use, and efficacy in lowering the rate of target lesion restenosis, it still requires additional development to reduce side effects and provide long-term clinical stability. Unfortunately, for analyzing these implants, there is still no globally accepted in vitro test method. This is owing to the stent's complexity as well as the dynamic arterial compartments of the blood and vascular wall. The former is the source of numerous biological, chemical, and physical mechanisms that are more commonly observed in tissue, lumen, and DES. As a result, universalizing bio-relevant apparatus, suitable for liberation testing of such complex implants is difficult. This article aims to provide a comprehensive review of the methods used for in vitro release testing of DESs. Aspects related to the correlation of the release profiles in the cases of in vitro and in vivo are also addressed.
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Affiliation(s)
- Navideh Abbasnezhad
- Arts et Métiers Institute of Technology, CNAM, LIFSE, HESAM University, F-75013 Paris, France; (N.Z.); (S.C.)
- Arts et Métiers Institute of Technology, CNAM, PIMM, HESAM University, F-75013 Paris, France;
| | - Nader Zirak
- Arts et Métiers Institute of Technology, CNAM, LIFSE, HESAM University, F-75013 Paris, France; (N.Z.); (S.C.)
- Arts et Métiers Institute of Technology, CNAM, PIMM, HESAM University, F-75013 Paris, France;
| | - Stéphane Champmartin
- Arts et Métiers Institute of Technology, CNAM, LIFSE, HESAM University, F-75013 Paris, France; (N.Z.); (S.C.)
| | - Mohammadali Shirinbayan
- Arts et Métiers Institute of Technology, CNAM, PIMM, HESAM University, F-75013 Paris, France;
| | - Farid Bakir
- Arts et Métiers Institute of Technology, CNAM, LIFSE, HESAM University, F-75013 Paris, France; (N.Z.); (S.C.)
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14
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Williamson PN, Docherty PD, Yazdi SG, Khanafer A, Kabaliuk N, Jermy M, Geoghegan PH. Review of the Development of Hemodynamic Modeling Techniques to Capture Flow Behavior in Arteries Affected by Aneurysm, Atherosclerosis, and Stenting. J Biomech Eng 2022; 144:1128816. [PMID: 34802061 DOI: 10.1115/1.4053082] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Indexed: 02/05/2023]
Abstract
Cardiovascular diseases (CVDs) are the leading cause of death in the developed world. CVD can include atherosclerosis, aneurysm, dissection, or occlusion of the main arteries. Many CVDs are caused by unhealthy hemodynamics. Some CVDs can be treated with the implantation of stents and stent grafts. Investigations have been carried out to understand the effects of stents and stent grafts have on arteries and the hemodynamic changes post-treatment. Numerous studies on stent hemodynamics have been carried out using computational fluid dynamics (CFD) which has yielded significant insight into the effect of stent mesh design on near-wall blood flow and improving hemodynamics. Particle image velocimetry (PIV) has also been used to capture behavior of fluids that mimic physiological hemodynamics. However, PIV studies have largely been restricted to unstented models or intra-aneurysmal flow rather than peri or distal stent flow behaviors. PIV has been used both as a standalone measurement method and as a comparison to validate the CFD studies. This article reviews the successes and limitations of CFD and PIV-based modeling methods used to investigate the hemodynamic effects of stents. The review includes an overview of physiology and relevant mechanics of arteries as well as consideration of boundary conditions and the working fluids used to simulate blood for each modeling method along with the benefits and limitations introduced.
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Affiliation(s)
- Petra N Williamson
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Paul D Docherty
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Sina G Yazdi
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Adib Khanafer
- Vascular, Endovascular, and Renal Transplant Unit, Christchurch Hospital, Canterbury District Health Board, Riccarton Avenue, Christchurch 8053, New Zealand; Christchurch School of Medicine, University of Otago, Dunedin 9016, New Zealand
| | - Natalia Kabaliuk
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Mark Jermy
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Patrick H Geoghegan
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK; Department of Mechanical and Industrial Engineering, University of South Africa, Johannesburg 2006, South Africa
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15
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Gharleghi R, Adikari D, Ellenberger K, Ooi SY, Ellis C, Chen CM, Gao R, He Y, Hussain R, Lee CY, Li J, Ma J, Nie Z, Oliveira B, Qi Y, Skandarani Y, Wang X, Yang S, Sowmya A, Beier S. Automated Segmentation of Normal and Diseased Coronary Arteries - The ASOCA Challenge. Comput Med Imaging Graph 2022; 97:102049. [DOI: 10.1016/j.compmedimag.2022.102049] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/07/2022] [Accepted: 02/10/2022] [Indexed: 12/19/2022]
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16
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Chiastra C, Mazzi V, Lodi Rizzini M, Calò K, Corti A, Acquasanta A, De Nisco G, Belliggiano D, Cerrato E, Gallo D, Morbiducci U. Coronary Artery Stenting Affects Wall Shear Stress Topological Skeleton. J Biomech Eng 2022; 144:1131202. [PMID: 35015058 DOI: 10.1115/1.4053503] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 01/09/2023]
Abstract
Despite the important advancements in the stent technology for the treatment of diseased coronary arteries, major complications still affect the post-operative long-term outcome. The stent-induced flow disturbances, and especially the altered wall shear stress (WSS) profile at the strut level, play an important role in the pathophysiological mechanisms leading to stent thrombosis (ST) and in-stent restenosis (ISR). In this context, the analysis of the WSS topological skeleton is gaining more and more interest by extending the current understanding of the association between local hemodynamics and vascular diseases. The present study aims to analyze the impact that a deployed coronary stent has on the WSS topological skeleton. Computational fluid dynamics simulations were performed in three stented human coronary artery geometries reconstructed from clinical images. The selected cases presented stents with different designs (i.e., two contemporary drug eluting stents and one bioresorbable scaffold) and included regions with stent malapposition or overlapping. A recently proposed Eulerian-based approach was applied to analyze the WSS topological skeleton features. The results highlighted that the presence of single or multiple stents within a coronary artery markedly impacts the WSS topological skeleton. In particular, repetitive patterns of WSS divergence were observed at the luminal surface, highlighting a WSS contraction action proximal to the struts and a WSS expansion action distal to the struts. This WSS action pattern was independent from the stent design. In conclusions, these findings could contribute to a deeper understanding of the hemodynamic-driven processes underlying ST and ISR.
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Affiliation(s)
- Claudio Chiastra
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Valentina Mazzi
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Maurizio Lodi Rizzini
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Karol Calò
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Anna Corti
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Alessandro Acquasanta
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Giuseppe De Nisco
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Davide Belliggiano
- Cardiology Division, San Luigi Gonzaga University Hospital, Orbassano, Turin, Italy
| | - Enrico Cerrato
- Interventional Cardiology Unit, San Luigi Gonzaga University Hospital, Orbassano, and Rivoli Infermi Hospital, Rivoli, Turin, Italy
| | - Diego Gallo
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Umberto Morbiducci
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
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17
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Shen C, Gharleghi R, Li DD, Stevens M, Dokos S, Beier S. Secondary flow in bifurcations - Important effects of curvature, bifurcation angle and stents. J Biomech 2021; 129:110755. [PMID: 34601214 DOI: 10.1016/j.jbiomech.2021.110755] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 09/01/2021] [Accepted: 09/16/2021] [Indexed: 12/27/2022]
Abstract
Coronary bifurcations have complex flow patterns including secondary flow zones and helical flow, which directly affect pathophysiological mechanisms such as the development of atherosclerosis. The objective of this study was to generate insights into the effects of curvature, bifurcation angle and the presence of stents on flow patterns and resulting haemodynamics in coronary left main bifurcations. The blood flow and associated metrics were modelled in both idealised and patient-specific bifurcations with varying curvature and bifurcation angles with and without stents, resulting in a total of 128 geometries considered. The results showed that larger curvature of bifurcating vessels has a significant influence on secondary flow, especially with distance to the bifurcation region, causing a skew, spin and asymmetry of Dean vortices, an increase in helical flow intensity with symmetry loss, and a decrease in adversely low time-average wall shear stress (TAWSS). Generally, asymmetric flow patterns coincided with adversely low TAWSS regions. In identical stented geometries, the presence of the stents induced local recirculation immediately adjacent to the stent struts, thus generating adversely low TAWSS in these areas, with some effect on the overall secondary flow. Overall, the effect of stents outweighed the effect of curvature and BA. This new knowledge contributes to a better understanding of the joint effects of curvature, bifurcation angle, and stents on flow patterns and haemodynamics in coronary bifurcations.
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Affiliation(s)
- C Shen
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney NSW 2052, Australia.
| | - R Gharleghi
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney NSW 2052, Australia
| | - D D Li
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney NSW 2052, Australia
| | - M Stevens
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney NSW 2052, Australia
| | - S Dokos
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney NSW 2052, Australia
| | - S Beier
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney NSW 2052, Australia
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18
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Gamage PT, Dong P, Lee J, Gharaibeh Y, Zimin VN, Dallan LAP, Bezerra HG, Wilson DL, Gu L. Hemodynamic alternations following stent deployment and post-dilation in a heavily calcified coronary artery: In silico and ex-vivo approaches. Comput Biol Med 2021; 139:104962. [PMID: 34715552 DOI: 10.1016/j.compbiomed.2021.104962] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/16/2021] [Accepted: 10/17/2021] [Indexed: 01/16/2023]
Abstract
In this work, hemodynamic alterations in a patient-specific, heavily calcified coronary artery following stent deployment and post-dilations are quantified using in silico and ex-vivo approaches. Three-dimensional artery models were reconstructed from OCT images. Stent deployment and post-dilation with various inflation pressures were performed through both the finite element method (FEM) and ex vivo experiments. Results from FEM agreed very well with the ex-vivo measurements, interms of lumen areas, stent underexpansion, and strut malapposition. In addition, computational fluid dynamics (CFD) simulations were performed to delineate the hemodynamic alterations after stent deployment and post-dilations. A pressure time history at the inlet and a lumped parameter model (LPM) at the outlet were adopted to mimic the aortic pressure and the distal arterial tree, respectively. The pressure drop across the lesion, pertaining to the clinical measure of instantaneous wave-free flow ratio (iFR), was investigated. Results have shown that post-dilations are necessary for the lumen gain as well as the hemodynamic restoration towards hemostasis. Malapposed struts induced much higher shear rate, flow disturbances and lower time-averaged wall shear stress (TAWSS) around struts. Post-dilations mitigated the strut malapposition, and thus the shear rate. Moreover, stenting induced larger area of low TAWSS (<0.4 Pa) and lager volume of high shear rate (>2000 s-1), indicating higher risks of in-stent restenosis (ISR) and stent thrombosis (ST), respectively. Oscillatory shear index (OSI) and relative residence time (RRT) indicated the wall regions more prone to ISR are located near the malapposed stent struts.
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Affiliation(s)
- Peshala T Gamage
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, 32901, USA
| | - Pengfei Dong
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, 32901, USA.
| | - Juhwan Lee
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yazan Gharaibeh
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Vladislav N Zimin
- Cardiovascular Imaging Core Laboratory, Harrington Heart & Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Luis A P Dallan
- Cardiovascular Imaging Core Laboratory, Harrington Heart & Vascular Institute, University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
| | - Hiram G Bezerra
- Interventional Cardiology Center, Heart and Vascular Institute, The University of South Florida, Tampa, FL, 33606, USA
| | - David L Wilson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Linxia Gu
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, 32901, USA.
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19
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Xue H, Saha SC, Beier S, Jepson N, Luo Z. Topological Optimization of Auxetic Coronary Stents Considering Hemodynamics. Front Bioeng Biotechnol 2021; 9:728914. [PMID: 34589473 PMCID: PMC8473832 DOI: 10.3389/fbioe.2021.728914] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/27/2021] [Indexed: 12/05/2022] Open
Abstract
This paper is to design a new type of auxetic metamaterial-inspired structural architectures to innovate coronary stents under hemodynamics via a topological optimization method. The new architectures will low the occurrence of stent thrombosis (ST) and in-stent restenosis (ISR) associated with the mechanical factors and the adverse hemodynamics. A multiscale level-set approach with the numerical homogenization method and computational fluid dynamics is applied to implement auxetic microarchitectures and stenting structure. A homogenized effective modified fluid permeability (MFP) is proposed to efficiently connect design variables with motions of blood flow around the stent, and a Darcy-Stokes system is used to describe the coupling behavior of the stent structure and fluid. The optimization is formulated to include three objectives from different scales: MFP and auxetic property in the microscale and stenting stiffness in the macroscale. The design is numerically validated in the commercial software MATLAB and ANSYS, respectively. The simulation results show that the new design can not only supply desired auxetic behavior to benefit the deliverability and reduce incidence of the mechanical failure but also improve wall shear stress distribution to low the induced adverse hemodynamic changes. Hence, the proposed stenting architectures can help improve safety in stent implantation, to facilitate design of new generation of stents.
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Affiliation(s)
- Huipeng Xue
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia
| | - Suvash C Saha
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia
| | - Susann Beier
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Nigel Jepson
- Department Cardiology, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Zhen Luo
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia
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20
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Abstract
Stenting is a common method for treating atherosclerosis. A metal or polymer stent is deployed to open the stenosed artery or vein. After the stent is deployed, the blood flow dynamics influence the mechanics by compressing and expanding the structure. If the stent does not respond properly to the resulting stress, vascular wall injury or re-stenosis can occur. In this work, a Discrete Multiphysics modelling approach is used to study the mechanical deformation of the coronary stent and its relationship with the blood flow dynamics. The major parameters responsible for deforming the stent are sorted in terms of dimensionless numbers and a relationship between the elastic forces in the stent and pressure forces in the fluid is established. The blood flow and the stiffness of the stent material contribute significantly to the stent deformation and affect its rate of deformation. The stress distribution in the stent is not uniform with the higher stresses occurring at the nodes of the structure. From the relationship (correlation) between the elastic force and the pressure force, depending on the type of material used for the stent, the model can be used to predict whether the stent is at risk of fracture or not after deployment.
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21
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Sun X, Ma T, Liu Z, Wu X, Zhang B, Zhu S, Li F, Chen M, Zheng Y, Liu X. Sequential numerical simulation of vascular remodeling and thrombosis in unconventional hybrid repair of ruptured middle aortic syndrome. Med Eng Phys 2021; 94:87-95. [PMID: 34303507 DOI: 10.1016/j.medengphy.2021.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 06/16/2021] [Accepted: 06/28/2021] [Indexed: 11/26/2022]
Abstract
Unconventional surgical procedures may be utilized in treating complicated middle aortic syndrome (MAS), the outcome and prognosis of which remain largely undetermined due to limited numbers and significant heterogeneity of this population. Using computational fluid dynamics (CFD) analysis, this study aimed to assess the dynamic changes of postoperative aortic flow in seeking to unveil the relationship between hemodynamics and vascular remodeling and thrombotic events. One patient with middle aortic syndrome complicated with aortic rupture was treated with hybrid repair of extra-anatomic bypass and fenestrated endovascular aortic repair. The patient was followed-up for 8 months by computational tomography angiography and Doppler ultrasound. Thoracoabdominal aortic blood flow and locations with ongoing thrombosis at 1, 3, and 6 months postoperatively were simulated and analyzed. Remodeling processes, including low wall shear-mediated constrictive remodeling of non-stented aorta, neointimal hyperplasia at suture lines, and minimal thrombosis at various locations, were evident. Meanwhile, abdominal blood flow was tri-phasic at 1 month after surgery, and was reversed and stabilized at 6 months. The distribution of newly formed thrombus vary at different follow-up stages, which were in line with the numerical simulation of thrombosis from different postoperative time points. CFD-based sequential monitoring is of promising value in capturing dynamic changes of vascular outcome.
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Affiliation(s)
- Xiaoning Sun
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Tianxiang Ma
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Zhili Liu
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Xiao Wu
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Bo Zhang
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China; Department of Diagnostic Ultrasound, China-Japan Friendship Hospital, Beijing 100029, China
| | - Shenling Zhu
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Fangda Li
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Mengyin Chen
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
| | - Yuehong Zheng
- Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
| | - Xiao Liu
- Beijing Advanced Innovation Center for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
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22
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A multi-objective optimization of stent geometries. J Biomech 2021; 125:110575. [PMID: 34186293 DOI: 10.1016/j.jbiomech.2021.110575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/06/2021] [Accepted: 06/08/2021] [Indexed: 11/22/2022]
Abstract
Stents are scaffolding cardiovascular implants used to restore blood flow in narrowed arteries. However, the presence of the stent alters local blood flow and shear stresses on the surrounding arterial wall, which can cause adverse tissue responses and increase the risk of adverse outcomes. There is a need for optimization of stent designs for hemodynamic performance. We used multi-objective optimization to identify ideal combinations of design variables by assessing potential trade-offs based on common hemodynamic indices associated with clinical risk and mechanical performance of the stents. We studied seven design variables including strut cross-section, strut dimension, strut angle, cell alignment, cell height, connector type and connector arrangement. Optimization objectives were the percentage of vessel area exposed to adversely low time averaged WSS (TAWSS) and adversely high Wall Shear Stress (WSS) assessed using computational fluid dynamics modeling, as well as radial stiffness of the stent using FEA simulation. Two multi-objective optimization algorithms were used and compared to iteratively predict ideal designs. Out of 50 designs, three best designs with respect to each of the three objectives, and two designs in regard to overall performance were identified.
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23
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Wei L, Wang J, Chen Q, Li Z. Impact of stent malapposition on intracoronary flow dynamics: An optical coherence tomography-based patient-specific study. Med Eng Phys 2021; 94:26-32. [PMID: 34303498 DOI: 10.1016/j.medengphy.2021.06.002] [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: 11/13/2020] [Revised: 05/10/2021] [Accepted: 06/04/2021] [Indexed: 10/21/2022]
Abstract
Percutaneous coronary intervention with stent implantation has emerged as a popular approach to treat coronary artery stenosis. Stent malapposition (SM), also referred as incomplete stent apposition, could reduce stent tissue coverage and hence increase the risk of late stent thrombosis. The objective of this study was to investigate the impact of SM on intracoronary flow dynamics by combining optical coherence tomography (OCT) image-based model reconstruction and computational analysis. Firstly, a stenosed coronary artery model was reconstructed from OCT and angiography imaging data of a patient. Two structural analyses were carried out to simulate two types of coronary artery stent implantations: a fully-apposed (FA) case and a SM case. Then, based on the two deformed coronary geometries, two computational fluid dynamics (CFD) analyses were performed to evaluate the differences of hemodynamic metrics between the FA and the SM cases, including wall shear stress (WSS), time-averaged WSS (TWSS), oscillatory shear index (OSI), WSS gradient (WSSG), time-averaged WSSG (TWSSG), and relative residence time (RRT). The results indicated that maximum flow velocity was higher in the SM case than that of the FA case, due to the incomplete expansion of the stent and artery. Moreover, the SM case had a lower percentage of areas of adverse WSS (< 0.5 Pa) and RRT (> 10/Pa) but a higher percentage of areas of adverse OSI (> 0.1) and WSSG (> 5000 Pa/m). Specifically, the differences of OSI, WSSG, and RRT between the two cases were relatively small. It was suggested that SM might not be responsible for negative hemodynamic metrics which would further result in stent thrombosis on the basis of the present specific model.
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Affiliation(s)
- Lingling Wei
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, PR China
| | - Jiaqiu Wang
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Qiang Chen
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, PR China.
| | - Zhiyong Li
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, PR China; School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane QLD 4001, Australia.
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24
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Impact of Malapposed and Overlapping Stents on Hemodynamics: A 2D Parametric Computational Fluid Dynamics Study. MATHEMATICS 2021. [DOI: 10.3390/math9080795] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Despite significant progress, malapposed or overlapped stents are a complication that affects daily percutaneous coronary intervention (PCI) procedures. These malapposed stents affect blood flow and create a micro re-circulatory environment. These disturbances are often associated with a change in Wall Shear Stress (WSS), Time-averaged WSS (TAWSS), relative residence time (RRT) and oscillatory character of WSS and disrupt the delicate balance of vascular biology, providing a possible source of thrombosis and restenosis. In this study, 2D axisymmetric parametric computational fluid dynamics (CFD) simulations were performed to systematically analyze the hemodynamic effects of malapposition and stent overlap for two types of stents (drug-eluting stent and a bioresorbable stent). The results of the modeling are mainly analyzed using streamlines, TAWSS, oscillatory shear index (OSI) and RRT. The risks of restenosis and thrombus are evaluated according to commonly accepted thresholds for TAWSS and OSI. The small malapposition distances (MD) cause both low TAWSS and high OSI, which are potential adverse outcomes. The region of low OSI decrease with MD. Overlap configurations produce areas with low WSS and high OSI. The affected lengths are relatively insensitive to the overlap distance. The effects of strut size are even more sensitive and adverse for overlap configurations compared to a well-applied stent.
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25
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Tarrahi I, Colombo M, Hartman EMJ, Tovar Forero MN, Torii R, Chiastra C, Daemen J, Gijsen FJH. Impact of bioresorbable scaffold design characteristics on local haemodynamic forces: an ex vivo assessment with computational fluid dynamics simulations. EUROINTERVENTION 2020; 16:e930-e937. [PMID: 31951204 DOI: 10.4244/eij-d-19-00657] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AIMS Bioresorbable scaffold (BRS) regions exposed to flow recirculation, low time-averaged wall shear stress (TAWSS) and high oscillatory shear index (OSI) develop increased neointima tissue. We investigated haemodynamic features in four different BRSs. METHODS AND RESULTS Fantom (strut height [SH] = 125 µm), Fantom Encore (SH = 98 µm), Absorb (SH = 157 µm) and Magmaris (SH = 150 µm) BRSs were deployed in phantom tubes and imaged with microCT. Both 2D and 3D geometrical scaffold models were reconstructed. Computational fluid dynamics (CFD) simulation was performed to compute TAWSS and OSI. Thicker struts had larger recirculation zones and lower TAWSS in 2D. Absorb had the largest recirculation zone and the lowest TAWSS (240 µm and -0.18 Pa), followed by Magmaris (170 µm and -0.15 Pa), Fantom (140 µm and -0.14 Pa) and Fantom Encore (100 µm and -0.13 Pa). Besides strut size, stent design played a dominant role in 3D. The highest percentage area adverse TAWSS (<0.5 Pa) and OSI (>0.2) were found for Fantom (56% and 30%) and Absorb (53% and 33%), followed by Fantom Encore (30% and 25%) and Magmaris (25% and 20%). Magmaris had the smallest areas due to a small footprint and rounded struts. CONCLUSIONS Due to stent design, both Fantom Encore and Magmaris showed smaller TAWSS and OSI than Fantom and Absorb. This study quantifies which scaffold features are most important to reduce long-term restenosis.
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Affiliation(s)
- Imane Tarrahi
- Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands
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26
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Saito N, Mori Y, Komatsu T. Influence of Stent Flexibility on Artery Wall Stress and Wall Shear Stress in Bifurcation Lesions. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2020; 13:365-375. [PMID: 33173357 PMCID: PMC7646508 DOI: 10.2147/mder.s275883] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/21/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose Stent flexibility can influence clinical outcome, especially in bifurcation lesions. For instance, an overly rigid stent can impose mechanical stress on the artery at the stent edges and alter both arterial geometry and blood flow dynamics in bifurcations. This study investigated the influence of stent flexibility on vessel geometry, histology, wall stress, and blood flow dynamics in arterial bifurcations. Materials and Methods We compared arterial angulation, stenosis, histopathology, simulated wall shear stress (WSS), and simulated blood flow velocity distribution in swine coronary artery bifurcations following placement of the less flexible Multi-link 8 or more flexible Kaname stent (4.1 ± 0.5 vs 1.5 ± 0.1 mN, p < 0.05, t-test). Stents were implanted into six coronary artery bifurcations each using the single-stent crossover technique without side branch strut dilatation. Outcomes were examined after 28 days. Results Implantation of both stents significantly increased site angulation (Multi-link 8: 148° ± 8° to 172° ± 2°, p < 0.05, paired t-test; Kaname: 152° ± 5° to 164° ± 4°, p < 0.05, paired t-test), but the change tended to be greater after Multi-link 8 stent implantation (24° ± 15° vs 11° ± 7°, p = 0.1, t-test), suggesting greater straightening of the bifurcation. The Multi-link 8 stent induced greater neointimal thickness than the Kaname stent (0.53 ± 0.3 mm vs 0.26 ± 0.1 mm, p < 0.05, t-test). The distribution of neointimal hyperplasia following stent implantation as revealed by longitudinal histopathology matched the distribution of WSS simulated using computational fluid dynamics (CFD). The endothelium at low WSS areas exhibited aberrant cell morphology and leukocyte adhesion. A CFD model of a curved bifurcation suggested that the region of low WSS is expanded by artery straightening. Conclusion In bifurcated lesions, stent flexibility influences not only mechanical stress on the artery but also WSS, which may induce local neointimal hyperplasia.
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Affiliation(s)
| | - Yuhei Mori
- Terumo Shonan Center, Kanagawa 259-0151, Japan
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He S, Liu W, Qu K, Yin T, Qiu J, Li Y, Yuan K, Zhang H, Wang G. Effects of different positions of intravascular stent implantation in stenosed vessels on in-stent restenosis: An experimental and numerical simulation study. J Biomech 2020; 113:110089. [PMID: 33181394 DOI: 10.1016/j.jbiomech.2020.110089] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 09/08/2020] [Accepted: 10/16/2020] [Indexed: 11/29/2022]
Abstract
Percutaneous coronary intervention (PCI) has been widely used in the treatment of atherosclerosis, while in-stent restenosis (ISR) has not been completely resolved. Studies have shown that changes in intravascular mechanical environment are related to ISR. Hence, an in-depth understanding of the effects of stent intervention on vascular mechanics is important for clinically optimizing stent implantation and relieving ISR. Nine rabbits with stenotic carotid artery were collected by balloon injury. Intravascular stents were implanted into different longitudinal positions (proximal, middle and distal relative to the stenotic area) of the stenotic vessels for numerical simulations. Optical coherence tomography (OCT) scanning was performed to reconstruct the three-dimensional configuration of the stented carotid artery and blood flow velocity waveforms were collected by Doppler ultrasound. The numerical simulations were performed through direct solution of Naiver-Stokes equation in ANSYS. Results showed that the distributions of time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and relative residual time (RRT) in near-end segment were distinctively different from other regions of the stent which considered to promote restenosis for all three models. Spearman rank-correlation analysis showed a significant correlation between hemodynamic descriptors and the stent longitudinal positions (rTAWSS = -0.718, rOSI = 0.898, rRRT = 0.818, p < 0.01). Histology results of the near-end segment showed neointima thickening deepened with the longitudinal positions of stent which was consistent with the numerical simulations. The results suggest that stent implantation can promote restenosis at the near-end segment. As the stenting position moves to distal end, the impact on ISR is more significant.
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Affiliation(s)
- Shicheng He
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China; State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China
| | - Wanling Liu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China
| | - Kai Qu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China
| | - Tieying Yin
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China
| | - Juhui Qiu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China.
| | - Yan Li
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China
| | - Kunshan Yuan
- National United Engineering Laboratory for Biomedical Material Modification, Dezhou, Shandong 251100, PR China
| | - Haijun Zhang
- National United Engineering Laboratory for Biomedical Material Modification, Dezhou, Shandong 251100, PR China
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing 400030, PR China.
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Tomaszewski M, Sybilski K, Baranowski P, Małachowski J. Experimental and numerical flow analysis through arteries with stent using particle image velocimetry and computational fluid dynamics method. Biocybern Biomed Eng 2020. [DOI: 10.1016/j.bbe.2020.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Wei L, Leo HL, Chen Q, Li Z. Structural and Hemodynamic Analyses of Different Stent Structures in Curved and Stenotic Coronary Artery. Front Bioeng Biotechnol 2019; 7:366. [PMID: 31867313 PMCID: PMC6908811 DOI: 10.3389/fbioe.2019.00366] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/12/2019] [Indexed: 12/30/2022] Open
Abstract
Coronary artery stenting is commonly used for the treatment of coronary stenosis, and different stent structures indeed have various impacts on the stress distribution within the plaque and artery as well as the local hemodynamic environment. This study aims to evaluate the performance of different stent structures by characterizing the mechanical parameters after coronary stenting. Six stent structures including three commercially-shaped stents (Palmaz-Schatz-shaped, Xience Prime-shaped, and Cypher-shaped) and three author-developed stents (C-Rlink, C-Rcrown, and C-Astrut) implanted into a curved stenotic coronary artery were investigated. Structural analyses of the balloon-stent-plaque-artery system were first performed, and then followed by hemodynamic analyses. The results showed that among the three commercially-shaped stents, the Palmaz-Schatz-shaped had the least stent dogboning and recoiling, corresponding to the greatest maximum plastic strain and the largest diameter change, nevertheless, it induced the highest maximum von Mises stress on plaque, arterial intima and media. From the viewpoint of hemodynamics, the Palmaz-Schatz-shaped displayed smaller areas of adverse low wall shear stress (<0.5 Pa), low time-averaged wall shear stress (<0.5 Pa), and high oscillating shear index (>0.1). Compared to the Cypher-shaped, the C-Rcrown and C-Astrut had smaller recoiling, greater maximum plastic stain and larger diameter change, which indicated the improved mechanical performance of the Cypher-shaped stent. Moreover, both C-Rcrown and C-Astrut exhibited smaller areas of adverse low wall shear stress, and low time-averaged wall shear stress, but only the C-Rcrown displayed a smaller area of adverse high oscillating shear index. The present study evaluated and compared the performance of six different stents deployed inside a curved artery, and could be potentially utilized as a guide for the selection of suitable commercially-shaped stent for clinical application, and to provide an approach to improve the performance of the commercial stents.
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Affiliation(s)
- Lingling Wei
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing, China
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Qiang Chen
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing, China
| | - Zhiyong Li
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing, China.,School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, Australia
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Bink N, Mohan VB, Fakirov S. Recent advances in plastic stents: a comprehensive review. INT J POLYM MATER PO 2019. [DOI: 10.1080/00914037.2019.1685519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Nienke Bink
- Plastics Centre of Excellence, Department of Mechanical Engineering, The University of Auckland, Auckland, New Zealand
- Centre for Advanced Composite Materials, Department of Mechanical Engineering, The University of Auckland, Auckland, New Zealand
- Department of Mechanics of Solids, Surfaces and Systems, Faculty of Engineering Technology, The University of Twente, Enschede, The Netherlands
| | - Velram Balaji Mohan
- Plastics Centre of Excellence, Department of Mechanical Engineering, The University of Auckland, Auckland, New Zealand
- Centre for Advanced Composite Materials, Department of Mechanical Engineering, The University of Auckland, Auckland, New Zealand
| | - Stoyko Fakirov
- Plastics Centre of Excellence, Department of Mechanical Engineering, The University of Auckland, Auckland, New Zealand
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Putra NK, Wang Z, Anzai H, Ohta M. Computational Fluid Dynamics Analysis to Predict Endothelial Cells Migration During Flow Exposure Experiment With Placement of Two Stent Wires. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2019; 2018:5454-5457. [PMID: 30441571 DOI: 10.1109/embc.2018.8513517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Stent deployment is currently used for many cardiovascular treatments. During its application, the presence of the stent inside the blood vessel will indeed cause some change in both flow environment and also vessel wall's cellular conditions. This research intends to learn about the flow phenomenon of how vessel wall endothelial cells (ECs) react to the presence of stent wires within a microfluidic flow chamber environment. Computational fluid dynamics (CFD) simulation analysis of the microfluidic flow chamber system has been performed for observing the hemodynamics phenomena in the chamber. Moreover, CFD method also can be beneficial as a planning step for a successful experimental study. We found that under the two wires configurations, high wall shear stress (WSS) area is developed on the downstream side of the wires. Based on the analysis of WSS and WSS gradients (WSSG) conditions, ECs morphological change and migration are likely to occur some specific area.
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Stiehm M, Wüstenhagen C, Siewert S, Ince H, Grabow N, Schmitz KP. Impact of strut dimensions and vessel caliber on thrombosis risk of bioresorbable scaffolds using hemodynamic metrics. ACTA ACUST UNITED AC 2019; 64:251-262. [PMID: 29933242 DOI: 10.1515/bmt-2017-0101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 05/18/2018] [Indexed: 11/15/2022]
Abstract
Bioresorbable scaffolds (BRS) promise to be the treatment of choice for stenosed coronary vessels. But higher thrombosis risk found in current clinical studies limits the expectations. Three hemodynamic metrics are introduced to evaluate the thrombosis risk of coronary stents/scaffolds using transient computational fluid dynamics (CFD). The principal phenomena are platelet activation and effective diffusion (platelet shear number, PSN), convective platelet transport (platelet convection number, PCN) and platelet aggregation (platelet aggregation number, PAN) were taken into consideration. In the present study, two different stent designs (thick-strut vs. thin-strut design) positioned in small- and medium-sized vessels (reference vessel diameter, RVD=2.25 mm vs. 2.70 mm) were analyzed. In both vessel models, the thick-strut design induced higher PSN, PCN and PAN values than the thin-strut design (thick-strut vs. thin-strut: PSN=2.92/2.19 and 0.54/0.30; PCN=3.14/1.15 and 2.08/0.43; PAN: 14.76/8.19 and 20.03/10.18 for RVD=2.25 mm and 2.70 mm). PSN and PCN are increased by the reduction of the vessel size (PSN: RVD=2.25 mm vs. 2.70 mm=5.41 and 7.30; PCN: RVD=2.25 mm vs. 2.70 mm=1.51 and 2.67 for thick-strut and thin-strut designs). The results suggest that bulky stents implanted in small caliber vessels may substantially increase the thrombosis risk. Moreover, sensitivity analyses imply that PSN is mostly influenced by vessel size (lesion-related factor), whereas PCN and PAN sensitively respond to strut-thickness (device-related factor).
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Affiliation(s)
- Michael Stiehm
- Institute for ImplantatTechnology and Biomaterials e.V., Friedrich-Barnewitz-Str. 4, 18119 Rostock-Warnemünde, Germany
| | - Carolin Wüstenhagen
- Institute for ImplantatTechnology and Biomaterials e.V., Friedrich-Barnewitz-Str. 4, 18119 Rostock-Warnemünde, Germany
| | - Stefan Siewert
- Institute for ImplantatTechnology and Biomaterials e.V., Friedrich-Barnewitz-Str. 4, 18119 Rostock-Warnemünde, Germany
| | - Hüseyin Ince
- Center for Internal Medicine, Department of Cardiology, Rostock University Medical Center, Ernst-Heydemann-Straße 6, 18057 Rostock, Germany
| | - Niels Grabow
- Institute for Biomedical Engineering, Rostock University Medical Center, Friedrich-Barnewitz-Str. 4, 18119 Rostock-Warnemünde, Germany
| | - Klaus-Peter Schmitz
- Institute for ImplantatTechnology and Biomaterials e.V., Friedrich-Barnewitz-Str. 4, 18119 Rostock-Warnemünde, Germany.,Institute for Biomedical Engineering, Rostock University Medical Center, Friedrich-Barnewitz-Str. 4, 18119 Rostock-Warnemünde, Germany
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Shen X, Jiang J, Deng Y, Zhu H, Lu K. Haemodynamics Study of Tapered Stents Intervention to Tapered Arteries. Cardiovasc Eng Technol 2019; 10:583-589. [DOI: 10.1007/s13239-019-00437-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 10/04/2019] [Indexed: 10/25/2022]
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Chen S, Feng H, Li X, Gu J, Wang X, Cao P, Wang Y. [Hemodynamic analysis of a new retrievable vena cava filter]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 2019; 36:245-253. [PMID: 31016941 PMCID: PMC9929894 DOI: 10.7507/1001-5515.201808032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Indexed: 06/09/2023]
Abstract
Vena cava filter is a filter device designed to prevent pulmonary embolism caused by thrombus detached from lower limbs and pelvis. A new retrievable vena cava filter was designed in this study. To evaluate hemodynamic performance and thrombus capture efficiency after transplanting vena cava filter, numerical simulation of computational fluid dynamics was used to simulate hemodynamics and compare it with the commercialized Denali and Aegisy filters, and in vitro experimental test was performed to compare the thrombus capture effect. In this paper, the two-phase flow model of computational fluid dynamics software was used to analyze the outlet blood flow velocity, inlet-outlet pressure difference, wall shear stress on the wall of the filter, the area ratio of the high and low wall shear stress area and thrombus capture efficiency when the thrombus diameter was 5 mm, 10 mm, 15 mm and thrombus content was 10%, 20%, 30%, respectively. Meanwhile, the thrombus capture effects of the above three filters were also compared and evaluated by in vitro experimental data. The results showed that the Denali filter has minimal interference to blood flow after implantation, but has the worst capture effect on 5 mm small diameter thrombus; the Aegisy filter has the best effect on the trapping of thrombus with different diameters and concentrations, but the low wall shear stress area ratio is the largest; the new filter designed in this study has a good filtering and capture efficiency on small-diameter thrombus, and the area ratio of low wall shear stress which is prone to thrombosis is small. The low wall shear stress area of the Denali and Aegisy filters is relatively large, and the risk of thrombosis is high. Based on the above results, it is expected that the new vena cava filter designed in this paper can provide a reference for the design and clinical selection of new filters.
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Affiliation(s)
- Siyuan Chen
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot 010000, P.R.China
| | - Haiquan Feng
- College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot 010000,
| | - Xiaoqiang Li
- Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210000, P.R.China
| | - Jianping Gu
- Nanjing Hospital Affiliated to Nanjing Medical University, Nanjing 210006, P.R.China
| | - Xiaotian Wang
- The First Affiliated Hospital of University of Science and Technology of China, Hefei 230000, P.R.China
| | - Ping Cao
- Shenzhen Medical Device Testing Center, Shenzhen, Guangdong 518057, P.R.China
| | - Yonggang Wang
- Suzhou Venmed Technology Co., Ltd, Suzhou, Jiangsu 215000, P.R.China
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Razavi SE, Farhangmehr V, Babaie Z. Numerical investigation of hemodynamic performance of a stent in the main branch of a coronary artery bifurcation. ACTA ACUST UNITED AC 2019; 9:97-103. [PMID: 31334041 PMCID: PMC6637217 DOI: 10.15171/bi.2019.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 12/11/2018] [Accepted: 12/26/2018] [Indexed: 01/09/2023]
Abstract
Introduction: The effect of a bare-metal stent on the hemodynamics in the main branch of a coronary artery bifurcation with a particular type of stenosis was numerically investigated by the computational fluid dynamics (CFD). Methods: Three-dimensional idealized geometry of bifurcation was constructed in Catia modelling commercial software package. The Newtonian blood flow was assumed to be incompressible and laminar. CFD was utilized to calculate the shear stress and blood pressure distributions on the wall of main branch. In order to do the numerical simulations, a commercial software package named as COMSOL Multiphysics 5.3 was employed. Two types of stent , namely, one-part stent and two-part stent were applied to prevent the build-up and progression of the atherosclerotic plaques in the main branch. Results: A particular type of stenosis in the main branch was considered in this research. It occurred before and after the side branch. Moreover, it was found that the main branch with an inserted one-part stent had the smallest region with the wall shear stress (WSS) below 0.5 Pa which was the minimum WSS in the main branch without the stenosis. Conclusion: The use of a one-part stent in the main branch of a coronary artery bifurcation for the aforementioned type of stenosis is recommended.
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Affiliation(s)
| | - Vahid Farhangmehr
- Department of Mechanical Engineering, University of Bonab, Bonab 5551761167, Iran
| | - Zahra Babaie
- Department of Mechanical Engineering, University of Tabriz, Tabriz, Iran
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Jiang B, Thondapu V, Poon E, Barlis P, Ooi A. Numerical study of incomplete stent apposition caused by deploying undersized stent in arteries with elliptical cross-sections. J Biomech Eng 2019; 141:2725823. [PMID: 30778567 DOI: 10.1115/1.4042899] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Indexed: 12/26/2022]
Abstract
Incomplete stent apposition (ISA) is one of the causes leading to post-stent complications, which can be found when an undersized or under-expanded stent is deployed at lesions. Previous research efforts have focused on ISA in idealized coronary arterial geometry with circular cross-sections. However, arterial cross-section eccentricity plays an important role in both location and severity of ISA. Computational fluid dynamics (CFD) simulations are carried out to systematically study the effects of ISA in arteries with elliptical cross-sections, as such stents are partially embedded on the minor axis sides of the ellipse and malapposed elsewhere. Overall, ISA leads to high time-averaged WSS (TAWSS) at the proximal end of the stent and low TAWSS at the ISA transition region and the distal end. Shear rate depends on both malapposition distance and blood stream locations, which is found to be significantly higher at the inner stent surface than the outer surface. The proximal high shear rate signifies increasing possibility in platelet activation, when coupled with low TAWSS at the transition and distal region which may indicate a nidus for in-stent thrombosis.
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Affiliation(s)
- Bo Jiang
- Department of Mechanical Engineering, The University of Melbourne, Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Vikas Thondapu
- Department of Mechanical Engineering, The University of Melbourne, Department of Medicine, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Eric Poon
- Department of Mechanical Engineering, The University of Melbourne, Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Peter Barlis
- Department of Medicine, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Department of Medicine, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Victoria 3010, Australia
| | - Andrew Ooi
- Department of Mechanical Engineering, The University of Melbourne, Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
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Tenekecioglu E, Torii R, Katagiri Y, Chichareon P, Asano T, Miyazaki Y, Takahashi K, Modolo R, Al-Lamee R, Al-Lamee K, Colet C, Reiber JHC, Pekkan K, van Geuns R, Bourantas CV, Onuma Y, Serruys PW. Post-implantation shear stress assessment: an emerging tool for differentiation of bioresorbable scaffolds. Int J Cardiovasc Imaging 2018; 35:409-418. [PMID: 30426299 PMCID: PMC6453863 DOI: 10.1007/s10554-018-1481-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 10/20/2018] [Indexed: 12/27/2022]
Abstract
Optical coherence tomography based computational flow dynamic (CFD) modeling provides detailed information about the local flow behavior in stented/scaffolded vessel segments. Our aim is to investigate the in-vivo effect of strut thickness and strut protrusion on endothelial wall shear stress (ESS) distribution in ArterioSorb Absorbable Drug-Eluting Scaffold (ArterioSorb) and Absorb everolimus-eluting Bioresorbable Vascular Scaffold (Absorb) devices that struts with similar morphology (quadratic structure) but different thickness. In three animals, six coronary arteries were treated with ArterioSorb. At different six animals, six coronary arteries were treated with Absorb. Following three-dimensional(3D) reconstruction of the coronary arteries, Newtonian steady flow simulation was performed and the ESS were estimated. Mixed effects models were used to compare ESS distribution in the two devices. There were 4591 struts in the analyzed 477 cross-sections in Absorb (strut thickness = 157 µm) and 3105 struts in 429 cross-sections in ArterioSorb (strut thickness = 95 µm) for the protrusion analysis. In cross-section level analysis, there was significant difference between the scaffolds in the protrusion distances. The protrusion was higher in Absorb (97% of the strut thickness) than in ArterioSorb (88% of the strut thickness). ESS was significantly higher in ArterioSorb (1.52 ± 0.34 Pa) than in Absorb (0.73 ± 2.19 Pa) (p = 0.001). Low- and very-low ESS data were seen more often in Absorb than in ArterioSorb. ArterioSorb is associated with a more favorable ESS distribution compared to the Absorb. These differences should be attributed to different strut thickness/strut protrusion that has significant effect on shear stress distribution.
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Affiliation(s)
- Erhan Tenekecioglu
- Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands
| | - Ryo Torii
- Department of Mechanical Engineering, University College London, London, UK
| | - Yuki Katagiri
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Ply Chichareon
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Taku Asano
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Yosuke Miyazaki
- Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands
| | - Kuniaki Takahashi
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rodrigo Modolo
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rasha Al-Lamee
- International Centre for Circulatory Health, Imperial College London, London, UK
| | | | - Carlos Colet
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Cardiology, Universitair Ziekenhuis Brussel, Brussel, Belgium
| | - Johan H C Reiber
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Istanbul, Turkey
| | - Robert van Geuns
- Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands
| | - Christos V Bourantas
- Department of Cardiology, University College of London Hospitals, London, UK.,Department of Cardiology, Barts Heart Centre, London, UK
| | - Yoshinobu Onuma
- Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands
| | - Patrick W Serruys
- Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands. .,Imperial College, London, UK. .,Dr.h.c. Melbourne School of Engineering, University of Melbourne, Melbourne (AUS), Westblaak 98, 3012KM, Rotterdam, The Netherlands.
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38
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Putra NK, Palar PS, Anzai H, Shimoyama K, Ohta M. Multiobjective design optimization of stent geometry with wall deformation for triangular and rectangular struts. Med Biol Eng Comput 2018; 57:15-26. [DOI: 10.1007/s11517-018-1864-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 06/18/2018] [Indexed: 12/26/2022]
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Wang J, Jin X, Huang Y, Ran X, Luo D, Yang D, Jia D, Zhang K, Tong J, Deng X, Wang G. Endovascular stent-induced alterations in host artery mechanical environments and their roles in stent restenosis and late thrombosis. Regen Biomater 2018; 5:177-187. [PMID: 29942650 PMCID: PMC6007795 DOI: 10.1093/rb/rby006] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/11/2018] [Accepted: 03/08/2018] [Indexed: 02/06/2023] Open
Abstract
Cardiovascular stent restenosis remains a major challenge in interventional treatment of cardiovascular occlusive disease. Although the changes in arterial mechanical environment due to stent implantation are the main causes of the initiation of restenosis and thrombosis, the mechanisms that cause this initiation are still not fully understood. In this article, we reviewed the studies on the issue of stent-induced alterations in arterial mechanical environment and discussed their roles in stent restenosis and late thrombosis from three aspects: (i) the interaction of the stent with host blood vessel, involve the response of vascular wall, the mechanism of mechanical signal transmission, the process of re-endothelialization and late thrombosis; (ii) the changes of hemodynamics in the lumen of the vascular segment and (iii) the changes of mechanical microenvironment within the vascular segment wall due to stent implantation. This review has summarized and analyzed current work in order to better solve the two main problems after stent implantation, namely in stent restenosis and late thrombosis, meanwhile propose the deficiencies of current work for future reference.
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Affiliation(s)
- Jinxuan Wang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Xuepu Jin
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Yuhua Huang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Xiaolin Ran
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Desha Luo
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Dongchuan Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Dongyu Jia
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Kang Zhang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
| | - Jianhua Tong
- Institute for Biomedical Engineering & Nano Science, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Guixue Wang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education; State and Local Joint Engineering Laboratory for Vascular Implants; Bioengineering College of Chongqing University, Chongqing, China
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Poon EKW, Thondapu V, Hayat U, Barlis P, Yap CY, Kuo PH, Wang Q, Ma J, Zhu SJ, Moore S, Ooi ASH. Elevated Blood Viscosity and Microrecirculation Resulting From Coronary Stent Malapposition. J Biomech Eng 2018; 140:2673009. [DOI: 10.1115/1.4039306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Indexed: 01/09/2023]
Abstract
One particular complexity of coronary artery is the natural tapering of the vessel with proximal segments having larger caliber and distal tapering as the vessel get smaller. The natural tapering of a coronary artery often leads to proximal incomplete stent apposition (ISA). ISA alters coronary hemodynamics and creates pathological path to develop complications such as in-stent restenosis, and more worryingly, stent thrombosis (ST). By employing state-of-the-art computer-aided design software, generic stent hoops were virtually deployed in an idealized tapered coronary artery with decreasing malapposition distance. Pulsatile blood flow simulations were carried out using computational fluid dynamics (CFD) on these computer-aided design models. CFD results reveal unprecedented details in both spatial and temporal development of microrecirculation environments throughout the cardiac cycle (CC). Arterial tapering also introduces secondary microrecirculation. These primary and secondary microrecirculations provoke significant fluctuations in arterial wall shear stress (WSS). There has been a direct correlation with changes in WSS and the development of atherosclerosis. Further, the presence of these microrecirculations influence strongly on the local levels of blood viscosity in the vicinity of the malapposed stent struts. The observation of secondary microrecirculations and changes in blood rheology is believed to complement the wall (-based) shear stress, perhaps providing additional physical explanations for tissue accumulation near ISA detected from high resolution optical coherence tomography (OCT).
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Affiliation(s)
- Eric K. W. Poon
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Vikas Thondapu
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia
- Faculty of Medicine, Dentistry, and Health Sciences, Department of Medicine, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Umair Hayat
- Faculty of Medicine, Dentistry and Health Sciences, Department of Medicine, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Peter Barlis
- Department of Medicine, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Chooi Yin Yap
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Po-Hung Kuo
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Qisen Wang
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Jiawei Ma
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Shuang J. Zhu
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
| | - Stephen Moore
- IBM Research Australia, Carlton 3053, Victoria, Australia e-mail:
| | - Andrew S. H. Ooi
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia e-mail:
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Rigatelli G, Dell'Avvocata F, Zuin M, Giatti S, Duong K, Pham T, Tuan NS, Vassiliev D, Daggubati R, Nguyen T. Comparative Computed Flow Dynamic Analysis of Different Optimization Techniques in Left Main Either Provisional or Culotte Stenting. J Transl Int Med 2017; 5:205-212. [PMID: 29340277 DOI: 10.1515/jtim-2017-0035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background and Objectives Provisional and culotte are the most commonly used techniques in left main (LM) stenting. The impact of different post-dilation techniques on fluid dynamic of LM bifurcation has not been yet investigated. The aim of this study is to evaluate, by means of computational fluid dynamic analysis (CFD), the impact of different post-dilation techniques including proximal optimization technique (POT), kissing balloon (KB), POT-Side-POT and POT-KB-POT, 2-steps Kissing (2SK) and Snuggle Kissing balloon (SKB) on flow dynamic profile after LM provisional or culotte stenting. Methods We considered an LM-LCA-LCX bifurcation reconstructed after reviewing 100 consecutive patients (mean age 71.4 ± 9.3 years, 49 males) with LM distal disease. The diameters of LAD and LCX were modelled according to the Finnet's law as following: LM 4.5 mm, LAD 3.5 mm, LCX 2.75 mm, with bifurcation angle set up at 55°. Xience third-generation stent (Abbot Inc., USA) was reconstructed and virtually implanted in provisional/cross-over and culotte fashion. POT, KB, POT-side-POT, POT-KB-POT, 2SK and SKB were virtually applied and analyzed in terms of the wall shear stress (WSS). Results Analyzing the provisional stenting, the 2SK and KB techniques had a statistically significant lower impact on the WSS at the carina, while POT seemed to obtain a neutral effect. In the wall opposite to the carina, the more physiological profile has been obtained by KB and POT with higher WSS value and smaller surface area of the lower WSS. In culotte stenting, at the carina, POT-KB-POT and 2SK had a very physiological profile; while at the wall opposite to the carina, 2SK and POT-KB-POT decreased significantly the surface area of the lower WSS compared to the other techniques. Conclusion From the fluid dynamic point of view in LM provisional stenting, POT, 2SK and KB showed a similar beneficial impact on the bifurcation rheology, while in LM culotte stenting, POT-KB-POT and 2SK performed slightly better than the other techniques, probably reflecting a better strut apposition.
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Affiliation(s)
- Gianluca Rigatelli
- Section of Cardiovascular Diagnosis and Endoluminal Interventions, Rovigo General Hospital, Rovigo, Italy
| | - Fabio Dell'Avvocata
- Section of Cardiovascular Diagnosis and Endoluminal Interventions, Rovigo General Hospital, Rovigo, Italy
| | - Marco Zuin
- Section of Cardiovascular Diagnosis and Endoluminal Interventions, Rovigo General Hospital, Rovigo, Italy
| | - Sara Giatti
- Section of Cardiovascular Diagnosis and Endoluminal Interventions, Rovigo General Hospital, Rovigo, Italy
| | - Khanh Duong
- Tan Tao University, School of Medicine, Long An, Vietnam
| | - Trung Pham
- Tan Tao University, School of Medicine, Long An, Vietnam
| | - Nguyen Si Tuan
- Tan Tao University, School of Medicine, Long An, Vietnam
| | - Dobrin Vassiliev
- Department of Cardiology, Alexandrovska University School of Medicine, Sofia, Bulgaria
| | - Ramesh Daggubati
- Cardiac Catheterization Laboratories, Winthrop University Hospital Mineola, Mineola, NY, USA
| | - Thach Nguyen
- Cardiovascular Research, Methodist Hospital, Merrillville IN, USA
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42
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Haemodynamic effects of incomplete stent apposition in curved coronary arteries. J Biomech 2017; 63:164-173. [DOI: 10.1016/j.jbiomech.2017.09.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/18/2017] [Accepted: 09/19/2017] [Indexed: 02/06/2023]
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Real-Time Electrical Bioimpedance Characterization of Neointimal Tissue for Stent Applications. SENSORS 2017; 17:s17081737. [PMID: 28788093 PMCID: PMC5579752 DOI: 10.3390/s17081737] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/17/2017] [Accepted: 07/25/2017] [Indexed: 11/29/2022]
Abstract
To follow up the restenosis in arteries stented during an angioplasty is an important current clinical problem. A new approach to monitor the growth of neointimal tissue inside the stent is proposed on the basis of electrical impedance spectroscopy (EIS) sensors and the oscillation-based test (OBT) circuit technique. A mathematical model was developed to analytically describe the histological composition of the neointima, employing its conductivity and permittivity data. The bioimpedance model was validated against a finite element analysis (FEA) using COMSOL Multiphysics software. A satisfactory correlation between the analytical model and FEA simulation was achieved in most cases, detecting some deviations introduced by the thin “double layer” that separates the neointima and the blood. It is hereby shown how to apply conformal transformations to obtain bioimpedance electrical models for stack-layered tissues over coplanar electrodes. Particularly, this can be applied to characterize the neointima in real-time. This technique is either suitable as a main mechanism for restenosis follow-up or it can be combined with proposed intelligent stents for blood pressure measurements to auto-calibrate the sensibility loss caused by the adherence of the tissue on the micro-electro-mechanical sensors (MEMSs).
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Stefopoulos G, Giampietro C, Falk V, Poulikakos D, Ferrari A. Facile endothelium protection from TNF-α inflammatory insult with surface topography. Biomaterials 2017; 138:131-141. [PMID: 28558298 DOI: 10.1016/j.biomaterials.2017.05.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/18/2017] [Accepted: 05/22/2017] [Indexed: 12/28/2022]
Abstract
Adverse events triggered by the direct contact between blood and synthetic materials constitute a sincere shortcoming of cardiovascular implant technology. A well-connected autologous endothelium, generated through the process of endothelialization, impedes such interaction and endows the implant luminal interface with optimal protection. The endothelialization of artificial substrates is the result of a complex interplay between endothelial cells (ECs), surface topography, and flow-generated wall shear stress (WSS). This is however tainted by the pro-inflammatory signaling, typical of cardiovascular patients, which compromises endothelial integrity and survival. Here, we challenge human endothelial monolayers with the pro-inflammatory factor TNF-α under realistic WSS conditions. In these experimental settings we demonstrate that the simple contact between ECs and an optimized surface geometry can inhibit NF-kB activation downstream of TNF-α yielding increased stability of VE-Cadherin mediated cell-to-cell junctions and of focal adhesions. Therefore the here-presented topographic modification can be implemented on a range of artificial substrates enabling their endothelialization under supra-physiological flow and in the presence of pro-inflammatory insults. These new findings constitute an important step toward achieving the full hemocompatibility of cardiovascular implants.
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Affiliation(s)
- Georgios Stefopoulos
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland
| | - Costanza Giampietro
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland
| | - Volkmar Falk
- Department of Cardiothoracic and Vascular Surgery, German Heart Institute Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Dimos Poulikakos
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland.
| | - Aldo Ferrari
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, CH-8092, Zurich, Switzerland.
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Karanasiou GS, Papafaklis MI, Conway C, Michalis LK, Tzafriri R, Edelman ER, Fotiadis DI. Stents: Biomechanics, Biomaterials, and Insights from Computational Modeling. Ann Biomed Eng 2017; 45:853-872. [PMID: 28160103 DOI: 10.1007/s10439-017-1806-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/28/2017] [Indexed: 01/02/2023]
Abstract
Coronary stents have revolutionized the treatment of coronary artery disease. Improvement in clinical outcomes requires detailed evaluation of the performance of stent biomechanics and the effectiveness as well as safety of biomaterials aiming at optimization of endovascular devices. Stents need to harmonize the hemodynamic environment and promote beneficial vessel healing processes with decreased thrombogenicity. Stent design variables and expansion properties are critical for vessel scaffolding. Drug-elution from stents, can help inhibit in-stent restenosis, but adds further complexity as drug release kinetics and coating formulations can dominate tissue responses. Biodegradable and bioabsorbable stents go one step further providing complete absorption over time governed by corrosion and erosion mechanisms. The advances in computing power and computational methods have enabled the application of numerical simulations and the in silico evaluation of the performance of stent devices made up of complex alloys and bioerodible materials in a range of dimensions and designs and with the capacity to retain and elute bioactive agents. This review presents the current knowledge on stent biomechanics, stent fatigue as well as drug release and mechanisms governing biodegradability focusing on the insights from computational modeling approaches.
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Affiliation(s)
- Georgia S Karanasiou
- Unit of Medical Technology and Intelligent Information Systems, Department of Materials Science, University of Ioannina, University Campus of Ioannina, Ioannina, 45100, Greece
- Foundation for Research and Technology-Hellas (FORTH), Ioannina, Greece
| | - Michail I Papafaklis
- Second Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
- Michailideion Cardiac Center, University of Ioannina, Ioannina, Greece
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Claire Conway
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lampros K Michalis
- Second Department of Cardiology, Medical School, University of Ioannina, Ioannina, Greece
- Michailideion Cardiac Center, University of Ioannina, Ioannina, Greece
| | - Rami Tzafriri
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- CBSET, Lexington, MA, USA
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dimitrios I Fotiadis
- Unit of Medical Technology and Intelligent Information Systems, Department of Materials Science, University of Ioannina, University Campus of Ioannina, Ioannina, 45100, Greece.
- Foundation for Research and Technology-Hellas (FORTH), Ioannina, Greece.
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Medrano-Gracia P, Ormiston J, Webster M, Beier S, Ellis C, Wang C, Smedby Ö, Young A, Cowan B. A Study of Coronary Bifurcation Shape in a Normal Population. J Cardiovasc Transl Res 2016; 10:82-90. [PMID: 28028693 PMCID: PMC5323506 DOI: 10.1007/s12265-016-9720-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 11/15/2016] [Indexed: 11/14/2022]
Abstract
During percutaneous coronary intervention, stents are placed in narrowings of the arteries to restore normal blood flow. Despite improvements in stent design, deployment techniques and drug-eluting coatings, restenosis and stent thrombosis remain a significant problem. Population stent design based on statistical shape analysis may improve clinical outcomes. Computed tomographic (CT) coronary angiography scans from 211 patients with a zero calcium score, no stenoses and no intermediate artery, were used to create statistical shape models of 446 major coronary artery bifurcations (left main, first diagonal and obtuse marginal and right coronary crux). Coherent point drift was used for registration. Principal component analysis shape scores were tested against clinical risk factors, quantifying the importance of recognised shape features in intervention including size, angles and curvature. Significant differences were found in (1) vessel size and bifurcation angle between the left main and other bifurcations; (2) inlet and curvature angle between the right coronary crux and other bifurcations; and (3) size and bifurcation angle by sex. Hypertension, smoking history and diabetes did not appear to have an association with shape. Physiological diameter laws were compared, with the Huo-Kassab model having the best fit. Bifurcation coronary anatomy can be partitioned into clinically meaningful modes of variation showing significant shape differences. A computational atlas of normal coronary bifurcation shape, where disease is common, may aid in the design of new stents and deployment techniques, by providing data for bench-top testing and computational modelling of blood flow and vessel wall mechanics.
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Affiliation(s)
- Pau Medrano-Gracia
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand.
| | | | | | - Susann Beier
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | | | - Chunliang Wang
- School of Technology and Health, KTH Royal Institute of Technology, Brinellvägen 8, Stockholm, Sweden
| | - Örjan Smedby
- School of Technology and Health, KTH Royal Institute of Technology, Brinellvägen 8, Stockholm, Sweden
| | - Alistair Young
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Brett Cowan
- Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
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Medrano-Gracia P, Ormiston J, Webster M, Beier S, Young A, Ellis C, Wang C, Smedby Ö, Cowan B. A computational atlas of normal coronary artery anatomy. EUROINTERVENTION 2016; 12:845-54. [DOI: 10.4244/eijv12i7a139] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Affiliation(s)
- John A. Ormiston
- From the Mercy Angiography, Auckland, New Zealand; Auckland City Hospital, New Zealand; and Department of Cardiology, University of Auckland School of Medicine, New Zealand
| | - Mark W.I. Webster
- From the Mercy Angiography, Auckland, New Zealand; Auckland City Hospital, New Zealand; and Department of Cardiology, University of Auckland School of Medicine, New Zealand
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49
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Beier S, Ormiston J, Webster M, Cater J, Norris S, Medrano-Gracia P, Young A, Cowan B. Impact of bifurcation angle and other anatomical characteristics on blood flow - A computational study of non-stented and stented coronary arteries. J Biomech 2016; 49:1570-1582. [PMID: 27062590 DOI: 10.1016/j.jbiomech.2016.03.038] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/01/2016] [Accepted: 03/23/2016] [Indexed: 01/14/2023]
Abstract
The hemodynamic influence of vessel shape such as bifurcation angle is not fully understood with clinical and quantitative observations being equivocal. The aim of this study is to use computational modeling to study the hemodynamic effect of shape characteristics, in particular bifurcation angle (BA), for non-stented and stented coronary arteries. Nine bifurcations with angles of 40°, 60° and 80°, representative of ±1 SD of 101 asymptomatic computed tomography angiogram cases (average age 54±8 years; 57 females), were generated for (1) a non-stented idealized, (2) stented idealized, and (3) non-stented patient-specific geometry. Only the bifurcation angle was changed while the geometries were constant to eliminate flow effects induced by other vessel shape characteristics. The commercially available Biomatrix stent was used as a template and virtually inserted into each branch, simulating the T-stenting technique. Three patient-specific geometries with additional shape variation and ±2 SD BA variation (33°, 42° and 117°) were also computed. Computational fluid dynamics (CFD) analysis was performed for all 12 geometries to simulate physiological conditions, enabling the quantification of the hemodynamic stress distributions, including a threshold analysis of adversely low and high wall shear stress (WSS), low time-averaged WSS (TAWSS), high spatial WSS gradient (WSSG) and high Oscillatory Shear Index (OSI) area. The bifurcation angle had a minor impact on the areas of adverse hemodynamics in the idealized non-stented geometries, which fully disappeared once stented and was not apparent for patient geometries. High WSS regions were located close to the carina around peak-flow, and WSSG increased significantly after stenting for the idealized bifurcations. Additional shape variations affected the hemodynamic profiles, suggesting that BA alone has little effect on a patient׳s hemodynamic profile. Incoming flow angle, diameter and tortuosity appear to have stronger effects. This suggests that other bifurcation shape characteristics and stent placement/strategy may be more important than bifurcation angle in atherosclerotic disease development, progression, and stent outcome.
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Affiliation(s)
- Susann Beier
- Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - John Ormiston
- Mercy Angiography, 98 Mountain Rd, Mt Eden, 1023, Auckland, New Zealand.
| | - Mark Webster
- Green Lane Cardiovascular Service, Auckland City Hospital, Park Rd, Auckland 1030, New Zealand.
| | - John Cater
- Faculty of Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Stuart Norris
- Faculty of Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Pau Medrano-Gracia
- Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Alistair Young
- Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Brett Cowan
- Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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