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Li M, Ma T, Cai Y, Li J, Meng Z, Dong Z, Wang S. Numerical simulation of the distal stent graft-induced new entry after TEVAR. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3819. [PMID: 38551141 DOI: 10.1002/cnm.3819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/16/2024] [Accepted: 03/19/2024] [Indexed: 05/15/2024]
Abstract
The study aimed to investigate the mechanical factors for distal stent graft-induced new entry (dSINE) in aortic dissection patients and discussed these factors in conjunction with aortic morphology. Two patients (one dSINE and one non-dSINE), with the same age, gender, and type of implanted stent, were selected, then aortic morphological parameters were calculated. In addition, the stent material parameters used by the patients were also fitted. Simulations were performed based on the patient's aortic model and the stent graft used. The true lumen segment at the distal stent graft was designated as the "dSINE risk zone," and mechanical parameters (maximum principal strain, maximum principal stress) were computed. When approaching the area with higher mechanical parameters in the dSINE risk zone, dSINE patient exhibited higher values and growth rates in mechanical parameters compared to non-dSINE patient. Furthermore, dSINE patient also presented larger aortic taper ratio, stent oversizing ratio, and expansion mismatch ratio of the distal true lumen (EMRDTR). The larger mechanical parameters and growth rates in dSINE patient corresponded to a greater aortic taper ratio, stent oversizing ratio, and EMRDTR. The failure of dSINE prediction by the stent tortuosity index indicated that mechanical parameters were the fundamental reasons for dSINE development.
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Affiliation(s)
- Meixuan Li
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Tao Ma
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, and National Clinical Research Center for Interventional Medicine, Shanghai, China
| | - Yunhan Cai
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Jianming Li
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Zhuangyuan Meng
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, and National Clinical Research Center for Interventional Medicine, Shanghai, China
| | - Shengzhang Wang
- Department of Aeronautics and Astronautics, Institute of Biomechanics, Fudan University, Shanghai, China
- Institute of Biomedical Engineering Technology, Academy of Engineering and Technology, Fudan University, Shanghai, China
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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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Liu H, Zhao G, Zhang GE, Xiong F, Hu S, Ouyang Y, Xiong F. Three-dimensional modelling and hemodynamic simulation of the closure of multiple entry tears in type B aortic dissection. Med Phys 2024; 51:42-53. [PMID: 38038366 DOI: 10.1002/mp.16852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 10/21/2023] [Accepted: 10/27/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Stanford type B aortic dissection (TB-AD) is a life-threatening vascular condition with high rates of morbidity and mortality. Currently, thoracic endovascular aortic repair (TEVAR) is widely performed to treat TB-AD, and some studies have analyzed the influence of stents on hemodynamics using computational fluid dynamics (CFD) models. However, the accuracy of TB-AD simulation models are not satisfactory, they are often constructed as a regular ideal model. Furthermore, it is unclear which tear should be closed for the best treatment when there are multi entry tears. PURPOSE The aims of this paper were to provide an assessment method for the selection of the surgical closure location for type B aortic dissection. Five 3D models of multiple entry tears in type B aortic dissection were produced using real patient computed tomography (CT) images to perform hemodynamic analyses of flow velocity streamlines, wall pressure, and wall shear stress. METHODS A Boolean operation was adopted to establish 3D models with multiple entry tears in type B aortic dissection based on patient-specific CT images. The Mimics and Ansys plug-in The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics (ICEM CFD) software were applied to mesh the 3D models. The flow velocity streamlines, wall pressures, and wall shear stresses were then analyzed in the finite element analysis software Fluent. Five 3D models were produced to compare the hemodynamic characteristics of different entry tear numbers, as well as the changes of different closure positions before and after closure. RESULTS The false lumen of the model with two entry tears had a higher wall pressure than that of model with multiple entry tears, which may tend to squeeze the true lumen and expand the false lumen. The load distribution of the vessel in the model with multiple entry tears had a more balanced flow velocity, and its wall pressure and shear stress were lower than that of model with two entry tears. For aortic dissection with two entry tears, the closure of the proximal entry tear was recommended, which helped to isolate and thrombose the false lumen, thereby improving the blood supply function of the true lumen. Because the postoperative vascular flow velocity and mechanical load performance of the vascular wall were still higher than those of normal blood vessels, the postoperative blood vessels remained pathological, and TEVAR did not restore the blood vessels to their original healthy state. CONCLUSIONS Type B aortic dissection with two entry tears tend to squeeze the true lumen and expand the false lumen, resulting in a new entry tear and deterioration into multiple entry type B aortic dissection. The model of the vessel with multiple entry tears had a more balanced distribution in flow velocity and a smaller wall pressure and shear stress than that of the vessel with two entry tears. The closure of the proximal entry tear was considered an ideal solution for type B aortic dissection with two entry tears.
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Affiliation(s)
- Hui Liu
- School of Mechanical Engineering, Guangxi University, Nanning, China
| | - Guolin Zhao
- School of Mechanical Engineering, Guangxi University, Nanning, China
| | | | - Feixiang Xiong
- School of Mechanical Engineering, Guangxi University, Nanning, China
| | - Shanshan Hu
- School of Mechanical Engineering, Guangxi University, Nanning, China
| | - Yang Ouyang
- Department of Vascular Surgery, XiangYa hospital, Central South University, Changsha, Hunan, China
| | - Fali Xiong
- School of Mechanical Engineering, Guangxi University, Nanning, China
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Mandigers TJ, Ramella A, Bissacco D, Domanin M, van Herwaarden JA, Heijmen R, Luraghi G, Migliavacca F, Trimarchi S. Thoracic Stent Graft Numerical Models To Virtually Simulate Thoracic Endovascular Aortic Repair: A Scoping Review. Eur J Vasc Endovasc Surg 2023; 66:784-796. [PMID: 37330201 DOI: 10.1016/j.ejvs.2023.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/23/2023] [Accepted: 06/06/2023] [Indexed: 06/19/2023]
Abstract
OBJECTIVE Pre-procedural planning of thoracic endovascular aortic repair (TEVAR) may implement computational adjuncts to predict technical and clinical outcomes. The aim of this scoping review was to explore the currently available TEVAR procedure and stent graft modelling options. DATA SOURCES PubMed (MEDLINE), Scopus, and Web of Science were systematically searched (English language, up to 9 December 2022) for studies presenting a virtual thoracic stent graft model or TEVAR simulation. REVIEW METHODS The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) was followed. Qualitative and quantitative data were extracted, compared, grouped, and described. Quality assessment was performed using a 16 item rating rubric. RESULTS Fourteen studies were included. Among the currently available in silico simulations of TEVAR, severe heterogeneity exists in study characteristics, methodological details, and evaluated outcomes. Ten studies (71.4%) were published during the last five years. Eleven studies (78.6%) included heterogeneous clinical data to reconstruct patient specific aortic anatomy and disease (e.g., type B aortic dissection, thoracic aortic aneurysm) from computed tomography angiography imaging. Three studies (21.4%) constructed idealised aortic models with literature input. The applied numerical methods consisted of computational fluid dynamics analysing aortic haemodynamics in three studies (21.4%) and finite element analysis analysing structural mechanics in the others (78.6%), including or excluding aortic wall mechanical properties. The thoracic stent graft was modelled as two separate components (e.g., graft, nitinol) in 10 studies (71.4%), as a one component homogenised approximation (n = 3, 21.4%), or including nitinol rings only (n = 1, 7.1%). Other simulation components included the catheter for virtual TEVAR deployment and numerous outcomes (e.g., Von Mises stresses, stent graft apposition, drag forces) were evaluated. CONCLUSION This scoping review identified 14 severely heterogeneous TEVAR simulation models, mostly of intermediate quality. The review concludes there is a need for continuous collaborative efforts to improve the homogeneity, credibility, and reliability of TEVAR simulations.
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Affiliation(s)
- Tim J Mandigers
- Section of Vascular Surgery, Cardio Thoracic Vascular Department, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy; Department of Vascular Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands.
| | - Anna Ramella
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, Milan, Italy
| | - Daniele Bissacco
- Section of Vascular Surgery, Cardio Thoracic Vascular Department, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maurizio Domanin
- Section of Vascular Surgery, Cardio Thoracic Vascular Department, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
| | - Joost A van Herwaarden
- Department of Vascular Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Robin Heijmen
- Department of Cardiothoracic Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Giulia Luraghi
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, Milan, Italy
| | - Francesco Migliavacca
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, Milan, Italy
| | - Santi Trimarchi
- Section of Vascular Surgery, Cardio Thoracic Vascular Department, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
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Derycke L, Avril S, Millon A. Patient-Specific Numerical Simulations of Endovascular Procedures in Complex Aortic Pathologies: Review and Clinical Perspectives. J Clin Med 2023; 12:jcm12030766. [PMID: 36769418 PMCID: PMC9917982 DOI: 10.3390/jcm12030766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
The endovascular technique is used in the first line treatment in many complex aortic pathologies. Its clinical outcome is mostly determined by the appropriate selection of a stent-graft for a specific patient and the operator's experience. New tools are still needed to assist practitioners with decision making before and during procedures. For this purpose, numerical simulation enables the digital reproduction of an endovascular intervention with various degrees of accuracy. In this review, we introduce the basic principles and discuss the current literature regarding the use of numerical simulation for endovascular management of complex aortic diseases. Further, we give the future direction of everyday clinical applications, showing that numerical simulation is about to revolutionize how we plan and carry out endovascular interventions.
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Affiliation(s)
- Lucie Derycke
- Department of Cardio-Vascular and Vascular Surgery, Hôpital Européen Georges Pompidou, F-75015 Paris, France
- Centre CIS, Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France
| | - Stephane Avril
- Centre CIS, Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, F-42023 Saint-Etienne, France
| | - Antoine Millon
- Department of Vascular and Endovascular Surgery, Hospices Civils de Lyon, Louis Pradel University Hospital, F-69500 Bron, France
- Correspondence:
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Peng C, Zou L, Hou K, Liu Y, Jiang X, Fu W, Yang Y, Bou-Said B, Wang S, Dong Z. Material parameter identification of the proximal and distal segments of the porcine thoracic aorta based on ECG-gated CT angiography. J Biomech 2022; 138:111106. [DOI: 10.1016/j.jbiomech.2022.111106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/28/2022] [Accepted: 04/26/2022] [Indexed: 11/16/2022]
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Hu H, Liu Z, Chen G, Yuan D, Zheng T. Analysis of aortic wall stress and morphology in patients with type B aortic dissection. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Kan X, Ma T, Lin J, Wang L, Dong Z, Xu XY. Patient-specific simulation of stent-graft deployment in type B aortic dissection: model development and validation. Biomech Model Mechanobiol 2021; 20:2247-2258. [PMID: 34431034 PMCID: PMC8595232 DOI: 10.1007/s10237-021-01504-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022]
Abstract
Thoracic endovascular aortic repair (TEVAR) has been accepted as the mainstream treatment for type B aortic dissection, but post-TEVAR biomechanical-related complications are still a major drawback. Unfortunately, the stent-graft (SG) configuration after implantation and biomechanical interactions between the SG and local aorta are usually unknown prior to a TEVAR procedure. The ability to obtain such information via personalised computational simulation would greatly assist clinicians in pre-surgical planning. In this study, a virtual SG deployment simulation framework was developed for the treatment for a complicated aortic dissection case. It incorporates patient-specific anatomical information based on pre-TEVAR CT angiographic images, details of the SG design and the mechanical properties of the stent wire, graft and dissected aorta. Hyperelastic material parameters for the aortic wall were determined based on uniaxial tensile testing performed on aortic tissue samples taken from type B aortic dissection patients. Pre-stress conditions of the aortic wall and the action of blood pressure were also accounted for. The simulated post-TEVAR configuration was compared with follow-up CT scans, demonstrating good agreement with mean deviations of 5.8% in local open area and 4.6 mm in stent strut position. Deployment of the SG increased the maximum principal stress by 24.30 kPa in the narrowed true lumen but reduced the stress by 31.38 kPa in the entry tear region where there was an aneurysmal expansion. Comparisons of simulation results with different levels of model complexity suggested that pre-stress of the aortic wall and blood pressure inside the SG should be included in order to accurately predict the deformation of the deployed SG.
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Affiliation(s)
- Xiaoxin Kan
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Tao Ma
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing Lin
- Key Laboratory of Textile Science and Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai, China
| | - Lu Wang
- Key Laboratory of Textile Science and Technology of Ministry of Education, College of Textiles, Donghua University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
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Ma T, Zhou M, Meng ZY, Wang S, Dong ZH, Fu WG. Computational Investigation and Histopathological Validation of Interaction Between Stent Graft and Aorta in Retrograde Type A Dissection After TEVAR in Canine Models. J Endovasc Ther 2021; 29:275-282. [PMID: 34384292 DOI: 10.1177/15266028211038596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE Retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) has been a major drawback of endovascular treatment. To our knowledge, no studies have simulated and validated aortic injuries caused by stent grafts (SGs) in animal models. Therefore, the aim of this study was to evaluate and quantify the SG-aorta interaction through computational simulations and to investigate the underlying mechanism through histopathological examinations. METHODS Two custom-made Fabulous® (DiNovA Meditech, Hang Zhou, China) SGs were implanted in 2 canine aortas with a 5-mm difference in the distance in landing locations. The aortic geometries were extracted from RTAD and non-RTAD cases. A computational SG model was assembled based on the implanted SG using the software Pro-ENGINEER Wildfire 5.0 (PTC Corporation, Needham, Mass). TEVAR simulations were performed 7 times for each canine model using Abaqus software (Providence, RI, USA), and the maximum aortic stress (MAS) was calculated and compared among the groups. Three months after SG implantation, the canine aortas were harvested, and were examined using hematoxylin and eosin staining and Elastica Van Gieson (EVG) staining to evaluate histopathological changes. RESULTS In the computational models for both canines, MAS was observed at the proximal bare stent (PBS) at aortic greater curve. The PBS generated higher stress toward the aortic wall than other SG parts did. Moreover, the MAS was significantly higher in canine No.1 than in canine No.2 (0.415±0.210 versus 0.200±0.160 MPa) (p<0.01). Notably, in canine No.1, an RTAD developed at the MAS segment, and histopathological examinations of the segment showed an intimal flap, a false lumen, elastin changes, and medial necrosis. RTAD was not observed in canine No.2. In both SG-covered aortas, medial necrosis, elastic fiber stretching, and inflammatory infiltration were seen. CONCLUSION The characteristic MAS distribution remained at the location where the apex of the PBS interacted with the aortic wall at greater curve. RTAD histopathological examinations showed intimal damage and medial necrosis at the proximal landing zone, at the same MAS location in computational simulations. The in vivo results were consistent with the computational simulations, suggesting the MAS at greater curve may cause RTAD, and the potential application of computational simulation in the mechanism study of RTAD.
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Affiliation(s)
- Tao Ma
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Min Zhou
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Zhuang Yuan Meng
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China.,Academy of Engineering and Technology, Fudan University, Shanghai, China
| | - Shengzhang Wang
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China.,Academy of Engineering and Technology, Fudan University, Shanghai, China
| | - Zhi Hui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Wei Guo Fu
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
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Kan X, Ma T, Dong Z, Xu XY. Patient-Specific Virtual Stent-Graft Deployment for Type B Aortic Dissection: A Pilot Study of the Impact of Stent-Graft Length. Front Physiol 2021; 12:718140. [PMID: 34381380 PMCID: PMC8349983 DOI: 10.3389/fphys.2021.718140] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Thoracic endovascular aortic repair (TEVAR) has been accepted as a standard treatment option for complicated type B aortic dissection. Distal stent-graft-induced new entry (SINE) is recognised as one of the main post-TEVAR complications, which can lead to fatal prognosis. Previous retrospective cohort studies suggested that short stent-graft (SG) length (<165 mm) might correlate with increased risk of distal SINE. However, the influence of SG length on changes in local biomechanical conditions before and after TEVAR is unknown. In this paper, we aim to address this issue using a virtual SG deployment simulation model developed for application in type B aortic dissection. Our model incorporates detailed SG design and hyperelastic behaviour of the aortic wall. By making use of patient-specific geometry reconstructed from pre-TEVAR computed tomography angiography (CTA) scan, our model can predict post-TEVAR SG configuration and wall stress. Virtual SG deployment simulations were performed on a patient who underwent TEVAR with a short SG (158 mm in length), mimicking the actual clinical procedure. Further simulations were carried out on the same patient geometry but with different SG lengths (183 mm and 208 mm) in order to evaluate the effect of SG length on changes in local stress in the treated aorta. Comparisons of simulation results for different SG lengths showed the location of maximum stress varied with the SG length. With the short SG (deployed in the patient), the maximum von Mises stress of 238.9 kPa was found on the intimal flap at the distal landing zone where SINE was identified at 3-month follow-up. Increasing the SG length caused the maximum von Mises stress to move away from the distal landing zone where stress values were reduced by approximately 17% with the medium-length SG and by 60% with the long SG. This pilot study demonstrates the potential of using the virtual SG deployment model as a pre-surgical planning tool to help select the most appropriate SG length for individual patients.
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Affiliation(s)
- Xiaoxin Kan
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Tao Ma
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
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