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Conway C, Nezami FR, Rogers C, Groothuis A, Squire JC, Edelman ER. Acute Stent-Induced Endothelial Denudation: Biomechanical Predictors of Vascular Injury. Front Cardiovasc Med 2021; 8:733605. [PMID: 34722666 PMCID: PMC8553954 DOI: 10.3389/fcvm.2021.733605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/15/2021] [Indexed: 01/03/2023] Open
Abstract
Recent concern for local drug delivery and withdrawal of the first Food and Drug Administration-approved bioresorbable scaffold emphasizes the need to optimize the relationships between stent design and drug release with imposed arterial injury and observed pharmacodynamics. In this study, we examine the hypothesis that vascular injury is predictable from stent design and that the expanding force of stent deployment results in increased circumferential stress in the arterial tissue, which may explain acute injury poststent deployment. Using both numerical simulations and ex vivo experiments on three different stent designs (slotted tube, corrugated ring, and delta wing), arterial injury due to device deployment was examined. Furthermore, using numerical simulations, the consequence of changing stent strut radial thickness on arterial wall shear stress and arterial circumferential stress distributions was examined. Regions with predicted arterial circumferential stress exceeding a threshold of 49.5 kPa compared favorably with observed ex vivo endothelial denudation for the three considered stent designs. In addition, increasing strut thickness was predicted to result in more areas of denudation and larger areas exposed to low wall shear stress. We conclude that the acute arterial injury, observed immediately following stent expansion, is caused by high circumferential hoop stresses in the interstrut region, and denuded area profiles are dependent on unit cell geometric features. Such findings when coupled with where drugs move might explain the drug–device interactions.
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Affiliation(s)
- Claire Conway
- Department of Anatomy and Regenerative Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA, United States.,Trinity Centre for Biomedical Engineering, Trinity College Dublin and Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Farhad R Nezami
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA, United States.,Thoracic and Cardiac Surgery Division, Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
| | - Campbell Rogers
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA, United States.,Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.,HeartFlow Inc., Redwood City, CA, United States
| | - Adam Groothuis
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA, United States
| | - James C Squire
- Department of Electrical and Computer Engineering, Virginia Military Institute, Lexington City, KY, United States
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA, United States.,Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States
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Wang X, Fang F, Ni Y, Yu H, Ma J, Deng L, Li C, Shen Y, Liu X. The Combined Contribution of Vascular Endothelial Cell Migration and Adhesion to Stent Re-endothelialization. Front Cell Dev Biol 2021; 9:641382. [PMID: 33748131 PMCID: PMC7969796 DOI: 10.3389/fcell.2021.641382] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Coronary stent placement inevitably causes mechanical damage to the endothelium, leading to endothelial denudation and in-stent restenosis (ISR). Re-endothelialization depends mainly on the migration of vascular endothelial cells (VECs) adjacent to the damaged intima, as well as the mobilization and adhesion of circulating VECs. To evaluate the combined contribution of VEC migration and adhesion to re-endothelialization under flow and the influence of stent, in vitro models were constructed to simulate various endothelial denudation scales (2 mm/5 mm/10 mm) and stent deployment depths (flat/groove/bulge). Our results showed that (1) in 2 mm flat/groove/bulge models, both VEC migration and adhesion combined completed the percentage of endothelial recovery about 27, 16, and 12%, and migration accounted for about 21, 15, and 7%, respectively. It was suggested that the flat and groove models were in favor of VEC migration. (2) With the augmentation of the injury scales (5 and 10 mm), the contribution of circulating VEC adhesion on endothelial repair increased. Taken together, endothelial restoration mainly depended on the migration of adjacent VECs when the injury scale was 2 mm. The adhered cells contributed to re-endothelialization in an injury scale-dependent way. This study is helpful to provide new enlightenment for surface modification of cardiovascular implants.
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Affiliation(s)
- Xiaoli Wang
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Fei Fang
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Yinghao Ni
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Hongchi Yu
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Jia Ma
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Li Deng
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Chunli Li
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Yang Shen
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
| | - Xiaoheng Liu
- West China School of Basic Medical Sciences and Forensic Medicine, Institute of Biomedical Engineering, Sichuan University, Chengdu, China
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Wu X, You W, Wu Z, Ye F, Chen S. Relationship between neointimal strut bridge and jailed side-branch ostial area. Herz 2019; 46:178-187. [PMID: 31555892 DOI: 10.1007/s00059-019-04856-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/29/2019] [Accepted: 08/28/2019] [Indexed: 11/25/2022]
Abstract
BACKGROUND Our study analyzed the relationship between the neointimal strut bridge and jailed side-branch (SB) ostial area in patients with coronary heart disease (CHD) who had a single drug-eluting stent (DES) crossover of the left anterior descending coronary artery (LAD)/diagonal branch (D) bifurcation. PATIENTS AND METHODS A total of 64 CHD patients with an LAD/D bifurcation treated by optical coherence tomography (OCT)-guided single-DES implantation and followed up at 1 year after primary percutaneous intervention (pPCI) were enrolled in our study. According to the two-dimensional OCT results, patients were divided into a non-neointimal bridge group (n = 44) and a neointimal bridge group (n = 20). Basic clinical, angiographic, 2D and 3D OCT, and DES results were analyzed. RESULTS The blood lipid levels of the two groups after the 1‑year follow-up were lower than the levels 1 year earlier (p < 0.05). There was a notable decrease in the SB ostial minimum lumen diameter and area directly after pPCI vs. before pPCI in both groups. The diameter stenosis directly after pPCI showed a clear increase compared with the pre-pPCI value in both groups (p < 0.05 or p < 0.01, respectively). The strut distance of the neointimal bridges in the neointimal bridge group was greater than in the non-neointimal bridge group (p < 0.05). A clearly short strut distance of the neointimal bridge was observed compared with the strut distance of the non-neointimal bridge in the neointimal bridge group (p < 0.05). A larger neointimal bridge area and a smaller SB ostial area were found in the neointimal bridge group compared with the non-neointimal bridge group (p < 0.05 or p < 0.01, respectively). CONCLUSION A short strut distance facilitated formation of a neointimal bridge, which significantly influenced the SB ostial area after single crossover stenting of the SB orifice at the 1‑year follow-up.
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Affiliation(s)
- Xiangqi Wu
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, 68 Changle Rd, 210006, Nanjing, China
| | - Wei You
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, 68 Changle Rd, 210006, Nanjing, China
| | - Zhiming Wu
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, 68 Changle Rd, 210006, Nanjing, China
| | - Fei Ye
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, 68 Changle Rd, 210006, Nanjing, China.
| | - Shaoliang Chen
- Division of Cardiology, Nanjing First Hospital, Nanjing Medical University, 68 Changle Rd, 210006, Nanjing, China.
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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: 3] [Impact Index Per Article: 0.6] [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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Conway C, Desany GJ, Bailey LR, Keating JH, Baker BL, Edelman ER. Fracture in drug-eluting stents increases focal intimal hyperplasia in the atherosclerosed rabbit iliac artery. Catheter Cardiovasc Interv 2018; 93:278-285. [PMID: 30244502 DOI: 10.1002/ccd.27726] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 04/30/2018] [Accepted: 06/10/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVES Drug-eluting stent (DES) strut fracture (SF) is associated with higher incidence of In-stent restenosis (ISR)-return of blockage in a diseased artery post stenting-than seen with bare metal stents (BMS). We hypothesize that concomitance of drug and SF leads to greater neointimal response. BACKGROUND Controlled release of therapeutic agents, such as sirolimus and its analogs, or paclitaxel from has reduced tissue based DES failure modes compared to BMS. ISR is dramatically reduced and yet the implications of mechanical device failure is magnified. METHODS Bilateral Xience Everolimus-eluting stents (EES) were implanted in 20 New Zealand White rabbits on normal (n = 7) or high fat (HF)/high cholesterol (HC) (n = 13) diets. Implanted stents were intact or mechanically fractured. Everolimus concentration was as packaged or pre-eluted. After 21 days, stented vessels were explanted, resin embedded, MicroCT scanned, and analyzed histomorphometrically. RESULTS Fractured EES were associated with significant (P < 0.05) increases in arterial stenosis and neointimal formation and lower lumen-to-artery area ratios compared to intact EES. Hyperlipidemic animals receiving pre-eluted EES revealed no significant difference between intact and fracture groups. CONCLUSIONS SF increases intimal hyperplasia, post EES implant, and worse with more advanced disease. Pre-eluted groups, reflective of BMS, did not show significant differences, suggesting a synergistic effect of everolimus and mechanical injury, potentially explaining the lack of SF reports for BMS. Here, we report that ISR has a higher incidence with SF in EES, the clinical implication is that patients with SF after DES implantation merit careful follow-up.
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Affiliation(s)
- Claire Conway
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Gerard J Desany
- Winchester Engineering and Analytical Center, US Food and Drug Administration, Winchester, Massachusetts
| | - Lynn R Bailey
- Concord Biomedical Sciences and Emerging Technologies, Lexington, Massachusetts
| | - John H Keating
- Concord Biomedical Sciences and Emerging Technologies, Lexington, Massachusetts
| | - Brian L Baker
- Winchester Engineering and Analytical Center, US Food and Drug Administration, Winchester, Massachusetts
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts.,Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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Brown J, O'Brien CC, Lopes AC, Kolandaivelu K, Edelman ER. Quantification of thrombus formation in malapposed coronary stents deployed in vitro through imaging analysis. J Biomech 2018; 71:296-301. [PMID: 29452756 PMCID: PMC5878124 DOI: 10.1016/j.jbiomech.2018.01.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 01/23/2018] [Accepted: 01/31/2018] [Indexed: 11/30/2022]
Abstract
Stent thrombosis is a major complication of coronary stent and scaffold intervention. While often unanticipated and lethal, its incidence is low making mechanistic examination difficult through clinical investigation alone. Thus, throughout the technological advancement of these devices, experimental models have been indispensable in furthering our understanding of device safety and efficacy. As we refine model systems to gain deeper insight into adverse events, it is equally important that we continue to refine our measurement methods. We used digital signal processing in an established flow loop model to investigate local flow effects due to geometric stent features and ultimately its relationship to thrombus formation. A new metric of clot distribution on each microCT slice termed normalized clot ratio was defined to quantify this distribution. Three under expanded coronary bare-metal stents were run in a flow loop model to induce clotting. Samples were then scanned in a MicroCT machine and digital signal processing methods applied to analyze geometric stent conformation and spatial clot formation. Results indicated that geometric stent features play a significant role in clotting patterns, specifically at a frequency of 0.6225 Hz corresponding to a geometric distance of 1.606 mm. The magnitude-squared coherence between geometric features and clot distribution was greater than 0.4 in all samples. In stents with poor wall apposition, ranging from 0.27 mm to 0.64 mm maximum malapposition (model of real-world heterogeneity), clots were found to have formed in between stent struts rather than directly adjacent to struts. This early work shows how the combination of tools in the areas of image processing and signal analysis can advance the resolution at which we are able to define thrombotic mechanisms in in vitro models, and ultimately, gain further insight into clinical performance.
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Affiliation(s)
- Jonathan Brown
- Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Caroline C O'Brien
- Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Augusto C Lopes
- Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kumaran Kolandaivelu
- Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Elazer R Edelman
- Institute of Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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7
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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: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/28/2017] [Indexed: 01/02/2023]
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Abstract
The coronary stent has propelled our understanding of the term "biocompatibility." Stents are expanded at sites of arterial blockage and mechanically reestablish blood flow. This simplicity belies the complex reactions that occur when a stent contacts living substrates. Biocompatible seek to elicit the intended response; stents should perform rather than merely exist. Because performance is assessed in the patient, stent biocompatibility is the multiscale examination of material and cell, and of material, structure, and device in the context of cell, tissue, and organism. This review tracks major biomaterial advances in coronary stent design and discusses biocompatibility clinical performance.
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Affiliation(s)
- Kumaran Kolandaivelu
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
| | - Farhad Rikhtegar
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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