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Mei J, Yan H, Zhao X, Yuan Y, Su H, Xue T, Jia Z. In-stent Restenosis After Stenting for Superior Mesenteric Artery Dissection Is Associated With Stent Landing Zone: From Clinical Prediction to Hemodynamic Mechanisms. J Endovasc Ther 2024:15266028241241494. [PMID: 38561992 DOI: 10.1177/15266028241241494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
OBJECTIVE To identify risk factors for in-stent restenosis (ISR) in patients undergoing stent placement for superior mesenteric artery dissection (SMAD) and to determine the hemodynamic mechanism underlying ISR. METHODS For this retrospective study, patients with SMAD who had ISR after stent placement were included in the ISR group, and age- and sex-matched patients with SMAD who did not experience ISR after stent placement were included in the control group. Clinical, imaging, and hemodynamic data were assessed. Multivariable regression was used to identify independent ISR risk factors. Structural and fluid dynamics simulations were applied to determine the hemodynamic mechanism underlying the occurrence of ISR. RESULTS The study population included 26 patients with ISR and 26 control patients. Multivariate analysis demonstrated that stent-to-vascular (S/V) ratio (odds ratio [OR], 1.14; 95% confidence interval [CI]: 1.00-1.29; p=0.045), stent proximal position >10 mm away from the SMA root (OR, 108.67; 95% CI: 3.09-3816.42; p=0.010), and high oscillatory shear index (OSI) area (OR, 1.25; 95% CI: 1.02-1.52; p=0.029) were predictors of ISR. In structural and fluid dynamics simulations, a stent proximal position near the abdominal aorta (AA) or entering into the AA reduced the contact area between the proximal struts of the stent and the vascular wall, and alleviated the distal lumen overdilation. CONCLUSION The S/V ratio, stent proximal position away from the SMA root (>10 mm), and high OSI area are independent risk factors for ISR in patients with SMAD undergoing stent placement. Deploying the proximal end of the stent near the AA or entering into the AA appears to improve the hemodynamic environment in the SMA lumen and ultimately reduce the risk of ISR. CLINICAL IMPACT In-stent restenosis is an uncommon but potentially catastrophic complication after stent placement for the management of superior mesenteric artery dissection. This study identified risk factors for in-stent restenosis and demonstrated that, as long as the stent can fully cover the dissection range, deploying the proximal end of the stent near the abdominal aorta or less entering into the abdominal aorta may reduce the risk of in-stent restenosis in this patient population.
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Affiliation(s)
- Junhao Mei
- Department of Interventional and Vascular Surgery, The Affiliated Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China
| | - Hui Yan
- Department of Radiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xi Zhao
- Central Research Institute, United Imaging Healthcare, Shanghai, China
| | - Yuan Yuan
- Department of Interventional Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Haobo Su
- Department of Interventional Radiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China
| | - Tongqing Xue
- Department of Interventional Radiology, Huaian Hospital of Huai'an City, Huai'an, China
| | - Zhongzhi Jia
- Department of Interventional and Vascular Surgery, The Affiliated Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China
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Song X, Qiu H, Wang S, Cao Y, Zhao J. Hemodynamic and Geometric Risk Factors for In-Stent Restenosis in Patients with Intracranial Atherosclerotic Stenosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:6951302. [PMID: 35936215 PMCID: PMC9348934 DOI: 10.1155/2022/6951302] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 06/12/2022] [Accepted: 07/05/2022] [Indexed: 12/03/2022]
Abstract
Methods Severe ICAS patients managed with percutaneous transluminal angioplasty and stenting (PTAS) were included in the retrospective cohort study and were divided into two groups according to whether ISR occurred at follow-up (ISR group and no-ISR group). Computational fluid dynamics models were built based on digital subtraction angiography before and after PTAS to simulate blood flow and quantify hemodynamic parameters. The associations between vessel geometry, hemodynamics, and ISR in ICAS patients were investigated. Results Among 39 patients, ISR occurred in seven patients (17.95%) after a mean follow-up period of 6.69 ± 3.24 months. Stenting decreased vessel angulation (51.11° [40.07°-67.27°] vs. 15.97° [0.00°-36.16°], P = 0.000) and vessel tortuosity (0.09 [0.06-0.13] vs. 0.01 [0.00-0.03], P = 0.000). Meanwhile, the translational pressure ratio (PR) dramatically increased (0.07 [0.00-0.31] vs. 0.62 [0.41-0.82], P = 0.000) with the wall shear stress ratio decreased (13.93 [8.37-40.30] vs. 2.90 [1.69-4.48], P = 0.000). In the multivariate analysis, smaller Δ tortuosity (P = 0.038) was independently associated with the occurrence of ISR, and smaller post-PTAS translesional PR was also a predictive factor of marginal significance (P = 0.059). Conclusion PTAS decreased vessel angulation, vessel tortuosity, and translesional wall shear stress ratio while it increased translesional pressure ratio (PR) dramatically in ICAS patients. Smaller Δ tortuosity was found to be a risk factor for ISR, and smaller post-PTAS translesional PR was also a predictive factor of marginal significance, indicating that both geometric and hemodynamic parameters played important roles in the occurrence of ISR after PTAS.
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Affiliation(s)
- Xiaowen Song
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Hancheng Qiu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Shuo Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Yong Cao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
| | - Jizong Zhao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- China National Clinical Research Center for Neurological Diseases, Beijing, China
- Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
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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: 8] [Impact Index Per Article: 2.7] [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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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: 5] [Impact Index Per Article: 1.7] [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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5
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Influence of Artery Straightening on Local Hemodynamics in Left Anterior Descending (LAD) Artery after Stent Implantation. Cardiol Res Pract 2020; 2020:6970817. [PMID: 32550022 PMCID: PMC7261340 DOI: 10.1155/2020/6970817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 04/20/2020] [Indexed: 11/29/2022] Open
Abstract
Objectives The study investigates local hemodynamic environment changes caused by straightening phenomenon and the relationship between straightening phenomenon and in-stent restenosis. Background Intravascular intervention is an effective treatment in restoring the normal flow conditions and vascular lumen. Unfortunately, in-stent restenosis often occurs in a subset of patients after stent implantation and limits the success of stent implantation outcomes. The implanted stent usually causes artery straightening locally, rather than coinciding and adjusting to the physiological curve exactly. Artery straightening would apparently modify the artery geometry and therefore alter the local hemodynamic environment, which may result in intimal hyperplasia and restenosis after stenting implantation. Methods In the current investigation, we verify the hypothesis that the artery straightening influences the local hemodynamic state using the different 3D CT models. Flow analysis for blood in the left anterior descending coronary artery and the straightening model is simulated numerically. Result The current results reveal that the straightening phenomenon alters the distribution of wall shear stress and flow patterns, decreases the wall shear stress (WSS), and increases the oscillatory shear index (OSI) and the relative residence time (RRT), especially at the proximal and distal areas of stenting. Conclusions The local straightened geometry established after stent implantation was likely to generate portions of the stenting area to a high risk of neointimal hyperplasia and subsequent restenosis.
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The Hemodynamic Effect of Enhanced External Counterpulsation Treatment on Atherosclerotic Plaque in the Carotid Artery: A Framework of Patient-Specific Computational Fluid Dynamics Analysis. Cardiol Res Pract 2020; 2020:5903790. [PMID: 32411447 PMCID: PMC7210552 DOI: 10.1155/2020/5903790] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/18/2019] [Accepted: 01/21/2020] [Indexed: 01/28/2023] Open
Abstract
Long-term enhanced external counterpulsation (EECP) therapy has been recommended for antiatherogenesis in recent clinical observations and trials. However, the precise mechanism underlying the benefits has not been fully clarified. To quantify the effect of EECP intervention on arterial hemodynamic environment, a framework of numerical assessment was introduced using a parallel computing algorithm. A 3D endothelial surface of the carotid artery with mild atherosclerotic plaque was constructed from images of magnetic resonance angiography (MRA). Physiologic boundary conditions were derived from images of the ultrasound flow velocity spectrum measured at the common carotid artery and before and during EECP intervention. Hemodynamic factors relating to wall shear stress (WSS) and its spatial and temporal fluctuations were calculated and analyzed, which included AWSS, OSI, and AWSSG. Measuring and computational results showed that diastole blood pressure, perfusion, and WSS level in carotid bifurcation were significantly increased during EECP intervention. Mean AWSS level throughout the model increased by 16.9%, while OSI level did not show a significant change during EECP. We thus suggested that long-term EECP treatment might inhibit the initiation and development of atherosclerotic plaque via improving the hemodynamic environment in the carotid artery. Meanwhile, EECP performance induced a 19.6% increase in AWSSG level, and whether it would influence the endothelial functions may need a further study. Moreover, the numerical method proposed in this study was expected to be useful for the instant assessment of clinical application of EECP .
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Boland EL, Grogan JA, McHugh PE. Computational modelling of magnesium stent mechanical performance in a remodelling artery: Effects of multiple remodelling stimuli. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3247. [PMID: 31393090 DOI: 10.1002/cnm.3247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 05/01/2019] [Accepted: 08/03/2019] [Indexed: 06/10/2023]
Abstract
Significant research has been conducted in the area of coronary stents/scaffolds made from resorbable metallic and polymeric biomaterials. These next-generation bioabsorbable stents have the potential to completely revolutionise the treatment of coronary artery disease. The primary advantage of resorbable devices over permanent stents is their temporary presence which, from a theoretical point of view, means only a healed coronary artery will be left behind following degradation of the stent potentially eliminating long-term clinical problems associated with permanent stents. The healing of the artery following coronary stent/scaffold implantation is crucial for the long-term safety of these devices. Computational modelling can be used to evaluate the performance of complex stent devices in silico and assist in the design and development and understanding of the next-generation resorbable stents. What is lacking in computational modelling literature is the representation of the active response of the arterial tissue in the weeks and months following stent implantation, ie, neointimal remodelling, in particular for the case of biodegradable stents. In this paper, a computational modelling framework is developed, which accounts for two major physiological stimuli responsible for neointimal remodelling and combined with a magnesium corrosion model that is capable of simulating localised pitting (realistic) stent corrosion. The framework is used to simulate different neointimal growth patterns and to explore the effects the neointimal remodelling has on the mechanical performance (scaffolding support) of the bioabsorbable magnesium stent.
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Affiliation(s)
- Enda L Boland
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - James A Grogan
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
| | - Peter E McHugh
- Biomechanics Research Centre (BioMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland
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Donadoni F, Bonfanti M, Pichardo-Almarza C, Homer-Vanniasinkam S, Dardik A, Díaz-Zuccarini V. An in silico study of the influence of vessel wall deformation on neointimal hyperplasia progression in peripheral bypass grafts. Med Eng Phys 2019; 74:137-145. [PMID: 31540730 DOI: 10.1016/j.medengphy.2019.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 08/08/2019] [Accepted: 09/08/2019] [Indexed: 10/26/2022]
Abstract
Neointimal hyperplasia (NIH) is a major obstacle to graft patency in the peripheral arteries. A complex interaction of biomechanical factors contribute to NIH development and progression, and although haemodynamic markers such as wall shear stress have been linked to the disease, these have so far been insufficient to fully capture its behaviour. Using a computational model linking computational fluid dynamics (CFD) simulations of blood flow with a biochemical model representing NIH growth mechanisms, we analyse the effect of compliance mismatch, due to the presence of surgical stitches and/or to the change in distensibility between artery and vein graft, on the haemodynamics in the lumen and, subsequently, on NIH progression. The model enabled to simulate NIH at proximal and distal anastomoses of three patient-specific end-to-side saphenous vein grafts under two compliance-mismatch configurations, and a rigid wall case for comparison, obtaining values of stenosis similar to those observed in the computed tomography (CT) scans. The maximum difference in time-averaged wall shear stress between the rigid and compliant models was 3.4 Pa, and differences in estimation of NIH progression were only observed in one patient. The impact of compliance on the haemodynamic-driven development of NIH was small in the patient-specific cases considered.
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Affiliation(s)
- Francesca Donadoni
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Mirko Bonfanti
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), Department of Medical Physics and Biomedical Engineering, University College London, W1W 7TS, UK
| | - Cesar Pichardo-Almarza
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Shervanthi Homer-Vanniasinkam
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK; Leeds Teaching Hospitals NHS Trust, LS1 3EX, UK; Division of Surgery, University of Warwick, Warwick, UK
| | - Alan Dardik
- The Department of Surgery, Yale University School of Medicine, New Haven, CT, USA; Veteran Affairs Connecticut Healthcare System, West Haven, CT, USA
| | - Vanessa Díaz-Zuccarini
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK; Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), Department of Medical Physics and Biomedical Engineering, University College London, W1W 7TS, UK.
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9
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Tenekecioglu E, Torii R, Katagiri Y, Asano T, Modolo R, Miyazaki Y, Chichareon P, Poon EKW, Gijsen FJH, Thondapu V, van Klaveren D, Jonker H, Ooi A, Barlis P, Collet C, Onuma Y, Bourantas CV, Serruys PW. Early strut protrusion and late neointima thickness in the Absorb bioresorbable scaffold: a serial wall shear stress analysis up to five years. EUROINTERVENTION 2019; 15:e370-e379. [PMID: 29969424 DOI: 10.4244/eij-d-18-00381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIMS The aim of the study was to evaluate the effect of strut protrusion (SP) on wall shear stress (WSS) and neointimal growth (NG) one and five years after implantation of an Absorb bioresorbable vascular scaffold. METHODS AND RESULTS Eight patients were selected from a first-in-man study. Following three-dimensional (3D) reconstruction of coronaries, WSS was quantified using Newtonian steady-flow simulation in each cross-section at 5° subunits (sectors) of the circumferential luminal surface. At one year, neointimal thickness (NT) was measured by optical coherence tomography (OCT) and correlated to WSS and SP post procedure. Median SP was 112.9 (90.8, 133.1) µm post implantation. Post procedure, a logarithmic inverse relationship between SP and post-implantation WSS (r=-0.425, p<0.001; correlation coefficients in a range from -0.143 to -0.553) was observed, whereas a correlation between baseline logarithm-transformed WSS (log-WSS) and NT (r=-0.451, p<0.001; correlation coefficients ranged from -0.140 to -0.662) was documented at one year. Mixed-effects analysis between baseline log-WSS and NT at follow-up yielded a slope of 30 µm/ln Pascal (Pa) and a y-intercept of 98 µm. As a result of NG, median flow area decreased from 6.91 (6.53, 7.48) mm2 post implantation to 5.65 (5.47, 6.02) mm2 at one-year follow-up (p=0.01) and to 5.75±1.37 mm2 at five-year follow-up (p=0.024). However, the vessel surface exposed to low WSS (<1 Pa) decreased significantly post procedure (42%) to one year (35.9%) and five years (15.2%) (p-overall <0.0001). CONCLUSIONS SP disturbs laminar flow, creates regions of low WSS (<1.0 Pa) that are associated with NG and lumen area reduction. Low WSS post implantation reduced significantly at long-term follow-up. Thin struts with effective embedment would substantially reduce NG and accelerate homogenisation of WSS towards physiological values.
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Affiliation(s)
- Erhan Tenekecioglu
- Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, the Netherlands
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10
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Marom G, Eswaran SK, Rapoza RJ, Hossainy SFA, Slepian MJ, Bluestein D. Design Effect of Metallic (Durable) and Polymeric (Resorbable) Stents on Blood Flow and Platelet Activation. Artif Organs 2018; 42:1148-1156. [DOI: 10.1111/aor.13276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/13/2018] [Accepted: 04/13/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Gil Marom
- Department of Biomedical Engineering; Stony Brook University; Stony Brook NY USA
- School of Mechanical Engineering; Tel Aviv University; Tel Aviv Israel
| | | | | | | | - Marvin J. Slepian
- Department of Biomedical Engineering; Stony Brook University; Stony Brook NY USA
- Departments of Medicine and Biomedical Engineering; Sarver Heart Center, University of Arizona; Tucson AZ USA
| | - Danny Bluestein
- Department of Biomedical Engineering; Stony Brook University; Stony Brook NY USA
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11
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Wain RAJ, Smith DJ, Hammond DR, Whitty JPM. Influence of microvascular sutures on shear strain rate in realistic pulsatile flow. Microvasc Res 2018. [PMID: 29522755 DOI: 10.1016/j.mvr.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Arterial thrombus formation is directly related to the mechanical shear experienced by platelets within flow. High shear strain rates (SSRs) and large shear gradients cause platelet activation, aggregation and production of thrombus. This study, for the first time, investigates the influence of pulsatile flow on local haemodynamics within sutured microarterial anastomoses. We measured physiological arterial waveform velocities experimentally using Doppler ultrasound velocimetry, and a representative example was applied to a realistic sutured microarterial geometry. Computational geometries were created using measurements taken from sutured chicken femoral arteries. Arterial SSRs were predicted using computational fluid dynamics (CFD) software, to indicate the potential for platelet activation, deposition and thrombus formation. Predictions of steady and sinusoidal inputs were compared to analyse whether the addition of physiological pulse characteristics affects local intravascular flow characteristics. Simulations were designed to evaluate flow in pristine and hand-sutured microarterial anastomoses, each with a steady-state and sinusoidal pulse component. The presence of sutures increased SSRmax in the anastomotic region by factors of 2.1 and 2.3 in steady-state and pulsatile flows respectively, when compared to a pristine vessel. SSR values seen in these simulations are analogous to the presence of moderate arterial stenosis. Steady-state simulations, driven by a constant inflow velocity equal to the peak systolic velocity (PSV) of the measured pulsatile flow, underestimated SSRs by ∼ 9% in pristine, and ∼ 19% in sutured vessels compared with a realistic pulse. Sinusoidal flows, with equivalent frequency and amplitude to a measured arterial waveform, represent a slight improvement on steady-state simulations, but still SSRs are underestimated by 1-2%. We recommend using a measured arterial waveform, of the form presented here, for simulating pulsatile flows in vessels of this nature. Under realistic pulsatile flow, shear gradients across microvascular sutures are high, of the order ∼ 7.9 × 106 m-1 s-1, which may also be associated with activation of platelets and formation of aggregates.
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Affiliation(s)
- R A J Wain
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute of Translational Medicine, University of Birmingham, B15 2TT, UK; School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK; Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK.
| | - D J Smith
- School of Mathematics, University of Birmingham, B15 2TT, UK; Institute for Metabolism and Systems Research, University of Birmingham, B15 2TT, UK
| | - D R Hammond
- School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - J P M Whitty
- Computational Mechanics Research Group, School of Engineering, University of Central Lancashire, Preston PR1 2HE, UK
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Documenting and predicting topic changes in Computers in Biology and Medicine: A bibliometric keyword analysis from 1990 to 2017. INFORMATICS IN MEDICINE UNLOCKED 2018. [DOI: 10.1016/j.imu.2018.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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13
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Katagiri Y, Tenekecioglu E, Serruys PW, Collet C, Katsikis A, Asano T, Miyazaki Y, Piek JJ, Wykrzykowska JJ, Bourantas C, Onuma Y. What does the future hold for novel intravascular imaging devices: a focus on morphological and physiological assessment of plaque. Expert Rev Med Devices 2017; 14:985-999. [DOI: 10.1080/17434440.2017.1407646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Yuki Katagiri
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | - Carlos Collet
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Athanasios Katsikis
- Department of Cardiology, General Military Hospital of Athens, Athens, Greece
| | - Taku Asano
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Yosuke Miyazaki
- ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Jan J Piek
- Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Christos Bourantas
- Barts Heart Centre, Barts Health NHS Trust, London, UK
- Institute of Cardiovascular Sciences, University College London, London, UK
| | - Yoshinobu Onuma
- ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands
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14
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Theodoridis K, Tudorache I, Cebotari S, Calistru A, Meyer T, Sarikouch S, Bara C, Haverich A, Hilfiker A. Six-Year-Old Sheep as a Clinically Relevant Large Animal Model for Aortic Valve Replacement Using Tissue-Engineered Grafts Based on Decellularized Allogenic Matrix. Tissue Eng Part C Methods 2017; 23:953-963. [DOI: 10.1089/ten.tec.2017.0163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Karolina Theodoridis
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Igor Tudorache
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Serghei Cebotari
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Alexandru Calistru
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Tanja Meyer
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Samir Sarikouch
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Christoph Bara
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Axel Haverich
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
| | - Andres Hilfiker
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
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15
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Anderson JA, Lamichhane S, Vierhout T, Engebretson D. Determining the cross-talk between smooth muscle cells and macrophages on a cobalt-chromium stent material surface using an in vitro postimplantation coculture model. J Biomed Mater Res A 2017; 106:673-685. [PMID: 29047206 DOI: 10.1002/jbm.a.36271] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/28/2017] [Accepted: 10/12/2017] [Indexed: 01/25/2023]
Abstract
Smooth muscle cells (SMCs) and macrophages are important cellular components involved in the development of complications following the implantation of cardiovascular devices. This leads to various disorders such as restenosis, chronic inflammation, and may ultimately result in device failure. In this study, we developed a postimplant stent coculture model using different ratios of SMCs and macrophages seeded on to cobalt-chromium alloy. The macrophages had an increased affinity to the coculture surfaces, which resulted in decreased SMC attachment to the alloy surfaces at the initial time point. Once adhered, the macrophages spread freely and displayed advanced stages of inflammation at 48 h when cocultured with SMCs. This resulted in an increased secretion of proinflammatory cytokines (tumor necrosis factor alpha, monocyte chemotactic protein 1, interleukin [IL]-6, and IL-8) by 48 h in the coculture samples with the greatest increase observed with the high number of macrophages. Therefore, the increased levels of proinflammatory cytokines promoted the growth of SMCs in coculture to a greater extent than when the SMCs were culture alone. Thus, this study demonstrated the constant cross-talk between SMCs and macrophages occurring on the postimplant stent surface. Similar coculture models can be used to test the biocompatibility of drugs and biomaterials at possible postimplantation scenarios. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 673-685, 2018.
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Affiliation(s)
- Jordan A Anderson
- Biomedical Engineering Department, The University of South Dakota, 4800 N. Career Avenue, Sioux Falls, South Dakota 57107
| | - Sujan Lamichhane
- Biomedical Engineering Department, The University of South Dakota, 4800 N. Career Avenue, Sioux Falls, South Dakota 57107
| | - Thomas Vierhout
- Biomedical Engineering Department, The University of South Dakota, 4800 N. Career Avenue, Sioux Falls, South Dakota 57107
| | - Daniel Engebretson
- Biomedical Engineering Department, The University of South Dakota, 4800 N. Career Avenue, Sioux Falls, South Dakota 57107
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16
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Donadoni F, Pichardo-Almarza C, Bartlett M, Dardik A, Homer-Vanniasinkam S, Díaz-Zuccarini V. Patient-Specific, Multi-Scale Modeling of Neointimal Hyperplasia in Vein Grafts. Front Physiol 2017; 8:226. [PMID: 28458640 PMCID: PMC5394124 DOI: 10.3389/fphys.2017.00226] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/30/2017] [Indexed: 11/16/2022] Open
Abstract
Neointimal hyperplasia is amongst the major causes of failure of bypass grafts. The disease progression varies from patient to patient due to a range of different factors. In this paper, a mathematical model will be used to understand neointimal hyperplasia in individual patients, combining information from biological experiments and patient-specific data to analyze some aspects of the disease, particularly with regard to mechanical stimuli due to shear stresses on the vessel wall. By combining a biochemical model of cell growth and a patient-specific computational fluid dynamics analysis of blood flow in the lumen, remodeling of the blood vessel is studied by means of a novel computational framework. The framework was used to analyze two vein graft bypasses from one patient: a femoro-popliteal and a femoro-distal bypass. The remodeling of the vessel wall and analysis of the flow for each case was then compared to clinical data and discussed as a potential tool for a better understanding of the disease. Simulation results from this first computational approach showed an overall agreement on the locations of hyperplasia in these patients and demonstrated the potential of using new integrative modeling tools to understand disease progression.
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Affiliation(s)
| | | | | | - Alan Dardik
- The Department of Surgery, Yale University School of MedicineNew Haven, CT, USA.,Veteran Affairs Connecticut Healthcare SystemWest Haven, CT, USA
| | - Shervanthi Homer-Vanniasinkam
- Mechanical Engineering, University College LondonLondon, UK.,Leeds Vascular Institute, Leeds General InfirmaryLeeds, UK.,Division of Surgery, University of WarwickWarwick, UK
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17
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Chen WX, Poon EKW, Hutchins N, Thondapu V, Barlis P, Ooi A. Computational fluid dynamics study of common stent models inside idealised curved coronary arteries. Comput Methods Biomech Biomed Engin 2017; 20:671-681. [PMID: 28349764 DOI: 10.1080/10255842.2017.1289374] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The haemodynamic behaviour of blood inside a coronary artery after stenting is greatly affected by individual stent features as well as complex geometrical properties of the artery including tortuosity and curvature. Regions at higher risk of restenosis, as measured by low wall shear stress (WSS < 0.5 Pa), have not yet been studied in detail in curved stented arteries. In this study, three-dimensional computational modelling and computational fluid dynamics methodologies were used to analyse the haemodynamic characteristics in curved stented arteries using several common stent models. Results in this study showed that stent strut thickness was one major factor influencing the distribution of WSS in curved arteries. Regions of low WSS were found behind struts, particularly those oriented at a large angle relative to the streamwise flow direction. These findings were similar to those obtained in studies of straight arteries. An uneven distribution of WSS at the inner and outer bends of curved arteries was observed where the WSS was lower at the inner bend. In this study, it was also shown that stents with a helical configuration generated an extra swirling component of the flow based on the helical direction; however, this extra swirl in the flow field did not cause significant changes on the distribution of WSS under the current setup.
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Affiliation(s)
- Winson X Chen
- a Department of Mechanical Engineering , Melbourne School of Engineering, The University of Melbourne , Parkville , Australia
| | - Eric K W Poon
- a Department of Mechanical Engineering , Melbourne School of Engineering, The University of Melbourne , Parkville , Australia
| | - Nicholas Hutchins
- a Department of Mechanical Engineering , Melbourne School of Engineering, The University of Melbourne , Parkville , Australia
| | - Vikas Thondapu
- b Faculty of Medicine, Dentistry & Health Sciences, Department of Medicine , The University of Melbourne , Parkville , Australia
| | - Peter Barlis
- b Faculty of Medicine, Dentistry & Health Sciences, Department of Medicine , The University of Melbourne , Parkville , Australia.,c Department of Cardiology , North-West Academic Centre, Melbourne Medical School, The University of Melbourne , Epping , Australia
| | - Andrew Ooi
- a Department of Mechanical Engineering , Melbourne School of Engineering, The University of Melbourne , Parkville , Australia
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18
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Yu Y, Zhou Y, Ma Q, jia S, Wu S, Sun Y, Liu X, Zhao Y, Liu Y, Shi D. The conical stent in coronary artery improves hemodynamics compared with the traditional cylindrical stent. Int J Cardiol 2017; 227:166-171. [DOI: 10.1016/j.ijcard.2016.11.065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 11/05/2016] [Indexed: 11/16/2022]
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19
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Iancu AC, Bălănescu Ș, Marc M, Homorodean C, Bindea D, Reimers B, Civilini E, Torsello G, Castriota F, Nerla R, Micari A, Cremonesi A. How should I treat renal artery in-stent restenosis and stent fracture after endovascular abdominal aortic aneurysm repair? EUROINTERVENTION 2016; 12:1312-1316. [PMID: 27866143 DOI: 10.4244/eijv12i10a216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Mazzitelli R, Boyle F, Murphy E, Renzulli A, Fragomeni G. Numerical prediction of the effect of aortic Left Ventricular Assist Device outflow-graft anastomosis location. Biocybern Biomed Eng 2016. [DOI: 10.1016/j.bbe.2016.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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21
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Antoniadis AP, Mortier P, Kassab G, Dubini G, Foin N, Murasato Y, Giannopoulos AA, Tu S, Iwasaki K, Hikichi Y, Migliavacca F, Chiastra C, Wentzel JJ, Gijsen F, Reiber JH, Barlis P, Serruys PW, Bhatt DL, Stankovic G, Edelman ER, Giannoglou GD, Louvard Y, Chatzizisis YS. Biomechanical Modeling to Improve Coronary Artery Bifurcation Stenting. JACC Cardiovasc Interv 2015; 8:1281-1296. [DOI: 10.1016/j.jcin.2015.06.015] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/05/2015] [Accepted: 06/18/2015] [Indexed: 02/04/2023]
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22
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Design Optimisation of Coronary Artery Stent Systems. Ann Biomed Eng 2015; 44:357-67. [DOI: 10.1007/s10439-015-1373-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
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23
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Local blood flow patterns in stented coronary bifurcations: an experimental and numerical study. J Appl Biomater Funct Mater 2015; 13:e116-26. [PMID: 25589159 DOI: 10.5301/jabfm.5000217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2014] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Despite the atheroprone environment of blood flow in coronary bifurcations, limited quantitative information is available on the hemodynamics occurring in these geometries, both before and after their treatment with endovascular stents. Previous studies have focused on computational fluid dynamics (CFD) analyses and have bypassed the challenges associated with experimentally representing the flow environment, providing no means for validation. This study analyzed steady flow conditions in 3 bifurcation angles and 4 different single- and double-stenting procedures, which are used clinically in coronary bifurcations. METHODS The numerical aspect of this study utilized geometries derived from CAD models (nonstented cases) and finite element simulations (stented cases). Digital particle image velocimetry (DPIV) testing was conducted within compliant bifurcating models for which an uncertainty analysis was performed at each measurement location for CFD validation purposes. Results were analyzed in terms of velocity magnitude contour maps and axial velocity profiles at several locations in the bifurcated vessels. RESULTS AND CONCLUSIONS Qualitatively, the 2 approaches showed agreement in the bulk flow patterns. However, the velocity computed with CFD was outside the DPIV uncertainty estimates, which can be attributed to the intrinsic difference and modeling assumptions of the 2 approaches. The findings reveal that wider bifurcation angles and double-stenting procedures are both characterized by increased areas of low flow and recirculation. Additionally, inferior performance in terms of viscous and wall shear stresses was observed in double-stented cases.
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24
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Sinclair MD, Lee J, Cookson AN, Rivolo S, Hyde ER, Smith NP. Measurement and modeling of coronary blood flow. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 7:335-56. [PMID: 26123867 DOI: 10.1002/wsbm.1309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 01/10/2023]
Abstract
Ischemic heart disease that comprises both coronary artery disease and microvascular disease is the single greatest cause of death globally. In this context, enhancing our understanding of the interaction of coronary structure and function is not only fundamental for advancing basic physiology but also crucial for identifying new targets for treating these diseases. A central challenge for understanding coronary blood flow is that coronary structure and function exhibit different behaviors across a range of spatial and temporal scales. While experimental studies have sought to understand this feature by isolating specific mechanisms, in tandem, computational modeling is increasingly also providing a unique framework to integrate mechanistic behaviors across different scales. In addition, clinical methods for assessing coronary disease severity are continuously being informed and updated by findings in basic physiology. Coupling these technologies, computational modeling of the coronary circulation is emerging as a bridge between the experimental and clinical domains, providing a framework to integrate imaging and measurements from multiple sources with mathematical descriptions of governing physical laws. State-of-the-art computational modeling is being used to combine mechanistic models with data to provide new insight into coronary physiology, optimization of medical technologies, and new applications to guide clinical practice.
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Affiliation(s)
- Matthew D Sinclair
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Andrew N Cookson
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Simone Rivolo
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Eoin R Hyde
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Nicolas P Smith
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK.,Department of Engineering, University of Auckland, Auckland, New Zealand
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25
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de Andrade Silva J, Karam-Filho J, Borges CCH. Computational Analysis of Anastomotic Angles by Blood Flow Conditions in Side-to-End Radio-Cephalic Fistulae Used in Hemodialysis. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/jbise.2015.83013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Wang LC, Scott DJ, Clemens MS, Hislop SJ, Arthurs ZM. Mechanism of Stent Failure in a Patient with Fibromuscular Dysplasia following Renal Artery Stenting. Ann Vasc Surg 2015; 29:123.e19-21. [DOI: 10.1016/j.avsg.2014.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 07/03/2014] [Accepted: 08/29/2014] [Indexed: 11/30/2022]
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27
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Poon EKW, Barlis P, Moore S, Pan WH, Liu Y, Ye Y, Xue Y, Zhu SJ, Ooi ASH. Numerical investigations of the haemodynamic changes associated with stent malapposition in an idealised coronary artery. J Biomech 2014; 47:2843-51. [PMID: 25132633 DOI: 10.1016/j.jbiomech.2014.07.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 07/10/2014] [Accepted: 07/29/2014] [Indexed: 10/24/2022]
Abstract
The deployment of a coronary stent near complex lesions can sometimes lead to incomplete stent apposition (ISA), an undesirable side effect of coronary stent implantation. Three-dimensional computational fluid dynamics (CFD) calculations are performed on simplified stent models (with either square or circular cross-section struts) inside an idealised coronary artery to analyse the effect of different levels of ISA to the change in haemodynamics inside the artery. The clinical significance of ISA is reported using haemodynamic metrics like wall shear stress (WSS) and wall shear stress gradient (WSSG). A coronary stent with square cross-sectional strut shows different levels of reverse flow for malapposition distance (MD) between 0mm and 0.12 mm. Chaotic blood flow is usually observed at late diastole and early systole for MD=0mm and 0.12 mm but are suppressed for MD=0.06 mm. The struts with circular cross section delay the flow chaotic process as compared to square cross-sectional struts at the same MD and also reduce the level of fluctuations found in the flow field. However, further increase in MD can lead to chaotic flow not only at late diastole and early systole, but it also leads to chaotic flow at the end of systole. In all cases, WSS increases above the threshold value (0.5 Pa) as MD increases due to the diminishing reverse flow near the artery wall. Increasing MD also results in an elevated WSSG as flow becomes more chaotic, except for square struts at MD=0.06 mm.
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Affiliation(s)
- Eric K W Poon
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia.
| | - Peter Barlis
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia; North West Academic Centre, Melbourne Medical School, The University of Melbourne, Victoria 3010, Australia
| | - Stephen Moore
- IBM Research Collaboratory for Life Sciences-Melbourne, Victoria Life Sciences Computation Initiative, The University of Melbourne, Victoria 3010, Australia
| | - Wei-Han Pan
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Yun Liu
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Yufei Ye
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Yuan Xue
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Shuang J Zhu
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Andrew S H Ooi
- Department of Mechanical Engineering, Melbourne School of Engineering, The University of Melbourne, Victoria 3010, Australia
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28
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Chiastra C, Migliavacca F, Martínez MÁ, Malvè M. On the necessity of modelling fluid–structure interaction for stented coronary arteries. J Mech Behav Biomed Mater 2014; 34:217-30. [DOI: 10.1016/j.jmbbm.2014.02.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 01/23/2014] [Accepted: 02/05/2014] [Indexed: 01/17/2023]
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29
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From Histology and Imaging Data to Models for In-Stent Restenosis. Int J Artif Organs 2014; 37:786-800. [DOI: 10.5301/ijao.5000336] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2014] [Indexed: 11/20/2022]
Abstract
The implantation of stents has been used to treat coronary artery stenosis for several decades. Although stenting is successful in restoring the vessel lumen and is a minimally invasive approach, the long-term outcomes are often compromised by in-stent restenosis (ISR). Animal models have provided insights into the pathophysiology of ISR and are widely used to evaluate candidate drug inhibitors of ISR. Such biological models allow the response of the vessel to stent implantation to be studied without the variation of lesion characteristics encountered in patient studies. This paper describes the development of complementary in silico models employed to improve the understanding of the biological response to stenting using a porcine model of restenosis. This includes experimental quantification using microCT imaging and histology and the use of this data to establish numerical models of restenosis. Comparison of in silico results with histology is used to examine the relationship between spatial localization of fluid and solid mechanics stimuli immediately post-stenting. Multi-scale simulation methods are employed to study the evolution of neointimal growth over time and the variation in the extent of neointimal hyperplasia within the stented region. Interpretation of model results through direct comparison with the biological response contributes to more detailed understanding of the pathophysiology of ISR, and suggests the focus for follow-up studies. In conclusion we outline the challenges which remain to both complete our understanding of the mechanisms responsible for restenosis and translate these models to applications in stent design and treatment planning at both population-based and patient-specific levels.
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30
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Keller BK, Amatruda CM, Hose DR, Gunn J, Lawford PV, Dubini G, Migliavacca F, Narracott AJ. Contribution of Mechanical and Fluid Stresses to the Magnitude of In-stent Restenosis at the Level of Individual Stent Struts. Cardiovasc Eng Technol 2014. [DOI: 10.1007/s13239-014-0181-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Caputo M, Chiastra C, Cianciolo C, Cutrì E, Dubini G, Gunn J, Keller B, Migliavacca F, Zunino P. Simulation of oxygen transfer in stented arteries and correlation with in-stent restenosis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2013; 29:1373-1387. [PMID: 23996860 DOI: 10.1002/cnm.2588] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 07/10/2013] [Accepted: 07/20/2013] [Indexed: 06/02/2023]
Abstract
Computational models are used to study the combined effect of biomechanical and biochemical factors on coronary in-stent restenosis, which is a postoperative remodeling and regrowth pathology of the stented arteries. More precisely, we address numerical simulations, on the basis of Navier-Stokes and mass transport equations, to study the role of perturbed wall shear stresses and reduced oxygen concentration in a geometrical model reconstructed from a real porcine artery treated with a stent. Joining in vivo and in silico tools of investigation has multiple benefits in this case. On one hand, the geometry of the arterial wall and of the stent closely correspond to a real implanted configuration. On the other hand, the inspection of histological tissue samples informs us on the location and intensity of in-stent restenosis. As a result, we are able to correlate geometrical factors, such as the axial variation of the artery diameter and its curvature; the numerical quantification of biochemical stimuli, such as wall shear stresses; and the availability of oxygen to the inner layers of the artery, with the appearance of in-stent restenosis. This study shows that the perturbation of the vessel curvature could induce hemodynamic conditions that stimulate undesired arterial remodeling.
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Affiliation(s)
- M Caputo
- LaBS, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Italy
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Tan T, Hu ZQ. Construction and expression of retroviral vector pLEGFP-N1-TERT in preparation of seed cells for skin tissue engineering. ASIAN PAC J TROP MED 2013; 6:960-3. [PMID: 24144027 DOI: 10.1016/s1995-7645(13)60171-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/15/2013] [Accepted: 11/15/2013] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To construct the retroviral vector pLEGFP-N1-telomerase reverse transcriptase (TERT) and to investigate the expression of TERT in neonatal mouse hypodermal cells. METHODS The polymerase chain reaction (PCR)-amplified TERT gene was inserted into plasmid pLEGFP-N1. The positive clone was identified by restriction enzyme digestion and sequencing, then was transfected into packaging cells to produce retrovirus particles. Neonatal mouse hypodermal cells were infected with the virus to generate a stable cell line. The TERT mRNA expression level, telomerase activity, and enhanced green fluorescent protein (EGFP) expression level were analyzed. RESULTS Retroviral vector pLEGFP-N1-TERT was constructed successfully, and a stable cell line of neonatal mouse hypodermal cells expressing EGFP was established. Western blot and immunohistochemical assay showed that the expression level of TERT was significantly elevated in the neonatal mouse hypodermal cells. CONCLUSIONS A high titer of retrovirus pLEGFP-N1-TERT mediates high-level expression of the exogenous TERT gene in the neonatal mouse hypodermal cells. This protocol has potential applications for skin tissue engineering and cell transplantation therapy.
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Affiliation(s)
- Ting Tan
- Epartment of Burn And Plastic Surgery, Fuzhou General Hospital of Nanjing Command, PLA, Fuzhou, China
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33
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Chiastra C, Morlacchi S, Gallo D, Morbiducci U, Cárdenes R, Larrabide I, Migliavacca F. Computational fluid dynamic simulations of image-based stented coronary bifurcation models. J R Soc Interface 2013; 10:20130193. [PMID: 23676893 DOI: 10.1098/rsif.2013.0193] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
One of the relevant phenomenon associated with in-stent restenosis in coronary arteries is an altered haemodynamics in the stented region. Computational fluid dynamics (CFD) offers the possibility to investigate the haemodynamics at a level of detail not always accessible within experimental techniques. CFD can quantify and correlate the local haemodynamics structures which might lead to in-stent restenosis. The aim of this work is to study the fluid dynamics of realistic stented coronary artery models which replicate the complete clinical procedure of stent implantation. Two cases of pathologic left anterior descending coronary arteries with their bifurcations are reconstructed from computed tomography angiography and conventional coronary angiography images. Results of wall shear stress and relative residence time show that the wall regions more prone to the risk of restenosis are located next to stent struts, to the bifurcations and to the stent overlapping zone for both investigated cases. Considering a bulk flow analysis, helical flow structures are generated by the curvature of the zone upstream from the stent and by the bifurcation regions. Helical recirculating microstructures are also visible downstream from the stent struts. This study demonstrates the feasibility to virtually investigate the haemodynamics of patient-specific coronary bifurcation geometries.
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Affiliation(s)
- Claudio Chiastra
- Chemistry, Materials and Chemical Engineering Department, Politecnico di Milano, Milan, Italy.
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Rikhtegar F, Pacheco F, Wyss C, Stok KS, Ge H, Choo RJ, Ferrari A, Poulikakos D, Müller R, Kurtcuoglu V. Compound ex vivo and in silico method for hemodynamic analysis of stented arteries. PLoS One 2013; 8:e58147. [PMID: 23516442 PMCID: PMC3596389 DOI: 10.1371/journal.pone.0058147] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/30/2013] [Indexed: 11/18/2022] Open
Abstract
Hemodynamic factors such as low wall shear stress have been shown to influence endothelial healing and atherogenesis in stent-free vessels. However, in stented vessels, a reliable quantitative analysis of such relations has not been possible due to the lack of a suitable method for the accurate acquisition of blood flow. The objective of this work was to develop a method for the precise reconstruction of hemodynamics and quantification of wall shear stress in stented vessels. We have developed such a method that can be applied to vessels stented in or ex vivo and processed ex vivo. Here we stented the coronary arteries of ex vivo porcine hearts, performed vascular corrosion casting, acquired the vessel geometry using micro-computed tomography and reconstructed blood flow and shear stress using computational fluid dynamics. The method yields accurate local flow information through anatomic fidelity, capturing in detail the stent geometry, arterial tissue prolapse, radial and axial arterial deformation as well as strut malapposition. This novel compound method may serve as a unique tool for spatially resolved analysis of the relationship between hemodynamic factors and vascular biology. It can further be employed to optimize stent design and stenting strategies.
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Affiliation(s)
- Farhad Rikhtegar
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Fernando Pacheco
- Department of Bioengineering, Imperial College, London, United Kingdom
| | - Christophe Wyss
- Clinic of Cardiology, University Hospital Zurich, Zurich, Switzerland
| | - Kathryn S. Stok
- Institute for Biomechanics, Department Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Heng Ge
- Clinic of Cardiology, University Hospital Zurich, Zurich, Switzerland
| | - Ryan J. Choo
- Institute for Biomechanics, Department Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Aldo Ferrari
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Dimos Poulikakos
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Ralph Müller
- Institute for Biomechanics, Department Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Vartan Kurtcuoglu
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
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35
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Computer Simulations in Stroke Prevention: Design Tools and Virtual Strategies Towards Procedure Planning. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0134-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Morlacchi S, Colleoni SG, Cárdenes R, Chiastra C, Diez JL, Larrabide I, Migliavacca F. Patient-specific simulations of stenting procedures in coronary bifurcations: two clinical cases. Med Eng Phys 2013; 35:1272-81. [PMID: 23428836 DOI: 10.1016/j.medengphy.2013.01.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 12/03/2012] [Accepted: 01/21/2013] [Indexed: 10/27/2022]
Abstract
Computational simulations of stenting procedures in idealized geometries can only provide general guidelines and their use in the patient-specific planning of percutaneous treatments is inadequate. Conversely, image-based patient-specific tools that are able to realistically simulate different interventional options might facilitate clinical decision-making and provide useful insights on the treatment for each individual patient. The aim of this work is the implementation of a patient-specific model that uses image-based reconstructions of coronary bifurcations and is able to replicate real stenting procedures following clinical indications. Two clinical cases are investigated focusing the attention on the open problems of coronary bifurcations and their main treatment, the provisional side branch approach. Image-based reconstructions are created combining the information from conventional coronary angiography and computed tomography angiography while structural finite element models are implemented to replicate the real procedure performed in the patients. First, numerical results show the biomechanical influence of stents deployment in the coronary bifurcations during and after the procedures. In particular, the straightening of the arterial wall and the influence of two overlapping stents on stress fields are investigated here. Results show that a sensible decrease of the vessel tortuosity occurs after stent implantation and that overlapping devices result in an increased stress state of both the artery and the stents. Lastly, the comparison between numerical and image-based post-stenting configurations proved the reliability of such models while replicating stent deployment in coronary arteries.
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Affiliation(s)
- Stefano Morlacchi
- Laboratory of Biological Structure Mechanics (LaBS), Chemistry, Materials and Chemical Engineering Department Giulio Natta, Politecnico di Milano, Italy.
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Morlacchi S, Migliavacca F. Modeling stented coronary arteries: where we are, where to go. Ann Biomed Eng 2012; 41:1428-44. [PMID: 23090621 DOI: 10.1007/s10439-012-0681-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/16/2012] [Indexed: 01/09/2023]
Abstract
In the last two decades, numerical models have become well-recognized and widely adopted tools to investigate stenting procedures. Due to limited computational resources and modeling capabilities, early numerical studies only involved simplified cases and idealized stented arteries. Nowadays, increased computational power allows for numerical models to meet clinical needs and include more complex cases such as the implantation of multiple stents in bifurcations or curved vessels. Interesting progresses have been made in the numerical modeling of stenting procedures both from a structural and a fluid dynamics points of view. Moreover, in the drug eluting stents era, new insights on drug elution capabilities are becoming essential in the stent development. Lastly, image-based methods able to reconstruct realistic geometries from medical images have been proposed in the recent literature aiming to better describe the peculiar anatomical features of coronary vessels and increase the accuracy of the numerical models. In this light, this review provides a comprehensive analysis of the current state-of-the-art in this research area, discussing the main methodological advances and remarkable results drawn from a number of significant studies.
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Affiliation(s)
- Stefano Morlacchi
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy.
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Morlacchi S, Chiastra C, Gastaldi D, Pennati G, Dubini G, Migliavacca F. Sequential Structural and Fluid Dynamic Numerical Simulations of a Stented Bifurcated Coronary Artery. J Biomech Eng 2011; 133:121010. [DOI: 10.1115/1.4005476] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Despite their success, stenting procedures are still associated to some clinical problems like sub-acute thrombosis and in-stent restenosis. Several clinical studies associate these phenomena to a combination of both structural and hemodynamic alterations caused by stent implantation. Recently, numerical models have been widely used in the literature to investigate stenting procedures but always from either a purely structural or fluid dynamic point of view. The aim of this work is the implementation of sequential structural and fluid dynamic numerical models to provide a better understanding of stenting procedures in coronary bifurcations. In particular, the realistic geometrical configurations obtained with structural simulations were used to create the fluid domains employed within transient fluid dynamic analyses. This sequential approach was applied to investigate the final kissing balloon (FKB) inflation during the provisional side branch technique. Mechanical stresses in the arterial wall and the stent as well as wall shear stresses along the arterial wall were examined before and after the FKB deployment. FKB provoked average mechanical stresses in the arterial wall almost 2.5 times higher with respect to those induced by inflation of the stent in the main branch only. Results also enlightened FKB benefits in terms of improved local blood flow pattern for the side branch access. As a drawback, the FKB generates a larger region of low wall shear stress. In particular, after FKB the percentage of area characterized by wall shear stresses lower than 0.5 Pa was 79.0%, while before the FKB it was 62.3%. For these reasons, a new tapered balloon dedicated to bifurcations was proposed. The inclusion of the modified balloon has reduced the mechanical stresses in the proximal arterial vessel to 40% and the low wall shear stress coverage area to 71.3%. In conclusion, these results show the relevance of the adopted sequential approach to study the wall mechanics and the hemodynamics created by stent deployment.
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Affiliation(s)
- Stefano Morlacchi
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, 20133 Milan, Italy; Department of Bioengineering, Politecnico di Milano, 20133 Milan, Italy
| | - Claudio Chiastra
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, 20133 Milan, Italy; Department of Bioengineering, Politecnico di Milano, 20133 Milan, Italy
| | - Dario Gastaldi
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, 20133 Milan, Italy
| | - Giancarlo Pennati
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, 20133 Milan, Italy
| | - Gabriele Dubini
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, 20133 Milan, Italy
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, 20133 Milan, Italy
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39
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Suh DC, Ko YB, Park ST, Yoon K, Lim OK, Oh JS, Jeong YG, Kim JS. Computational flow dynamics of the severe m1 stenosis before and after stenting. Neurointervention 2011; 6:13-6. [PMID: 22125742 PMCID: PMC3214803 DOI: 10.5469/neuroint.2011.6.1.13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 01/26/2011] [Indexed: 11/24/2022] Open
Abstract
Purpose Computational flow dynamic (CFD) study has not been widely applied in intracranial artery stenosis due to requirement of high resolution in identifying the small intracranial artery. We described a process in CFD study applied to symptomatic severe intracranial (M1) stenosis before and after stenting. Materials and Methods Reconstructed 3D angiography in STL format was transferred to Magics (Materialise NV, Leuven, Belgium) for smoothing of vessel surface and trimming of branch vessels and to HyperMesh (Altair Engineering Inc., Auckland, New Zealand) for generating tetra volume mesh from triangular surface-meshed 3D angiogram. Computational analysis of blood flow in the blood vessels was performed using the commercial finite element software ADINA Ver 8.5 (ADINA R & D, Inc., Lebanon, MA). The distribution of wall shear stress (WSS), peak velocity and pressure in a patient was analyzed before and after intracranial stenting. Results Computer simulation of wall shear stress, flow velocity and wall pressure before and after stenting could be demonstrated three dimensionally by video mode according to flow vs. time dimension. Such flow model was well correlated with angiographic finding related to maximum degree of stenosis. Change of WSS, peak velocity and pressure at the severe stenosis was demonstrated before and after stenting. There was no WSS after stenting in case without residual stenosis. Conclusion Our study revealed that CFD analysis before and after intracranial stenting was feasible despite of limited vessel wall dimension and could reveal change of WSS as well as flow velocity and wall pressure.
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Affiliation(s)
- Dae Chul Suh
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, Seoul, Korea
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