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Zhu Z, Ji S, Liang L, Wang H, Xia H, Tang P. Hemodynamic study of blood flow in the aorta during the interventional robot treatment using fluid-structure interaction. Biomech Model Mechanobiol 2023; 22:1857-1872. [PMID: 37329426 PMCID: PMC10613174 DOI: 10.1007/s10237-023-01737-y] [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: 04/26/2023] [Accepted: 06/08/2023] [Indexed: 06/19/2023]
Abstract
An interventional robot is a means for vascular diagnosis and treatment, and it can perform dredging, releasing drug and operating. Normal hemodynamic indicators are a prerequisite for the application of interventional robots. The current hemodynamic research is limited to the absence of interventional devices or interventional devices in fixed positions. Considering the coupling effect of blood, vessels and robots, based on the bi-directional fluid-structure interaction, using the computational fluid dynamics and particle image velocimetry methods, combined with the sliding and moving mesh technologies, we theoretically and experimentally study the hemodynamic indicators such as blood flow lines, blood pressure, equivalent stress, deformation and wall shear stress of blood vessels when the robot precesses, rotates or does not intervene in the pulsating blood flow. The results show that the intervention of the robot increase the blood flow rate, blood pressure, equivalent stress and deformation of the vessels by 76.4%, 55.4%, 76.5%, and 346%, respectively. The operating mode of the robot during low-speed operation has little impact on the hemodynamic indicators. Using the methyl silicone oil as the experimental fluid, the elastic silicone pipe as the experimental pipe, and the intervention robot having a bioplastic outer shell, the velocity of the fluid around the robot is measured on the developed experimental device for fluid flow field in a pulsating flow when the robot runs. The experimental results are similar to the numerical results. Our work provides an important reference for the hemodynamic study and optimization of the mobile interventional devices.
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Affiliation(s)
- Zongming Zhu
- College of Electromechanical Engineering, Changsha University, Changsha, 410022, China
| | - Suqiang Ji
- School of Mechanical Engineering and Mechanics, Xiangtan University, Xiangtan, 411105, China
| | - Liang Liang
- College of Electromechanical Engineering, Changsha University, Changsha, 410022, China.
| | - Hao Wang
- College of Engineering and Design, Hunan Normal University, Changsha, 410081, China
| | - Haoyu Xia
- Changsha Institute of Mining Research Co., LTD, Changsha, 410012, China
| | - Puhua Tang
- College of Electromechanical Engineering, Changsha University, Changsha, 410022, China
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Kim MK, Kim JG, Kim CS, Park KB, Yang SS, Park YJ. Repeated Pseudoaneurysm after Endovascular Repair of Popliteal Aneurysm due to Graft Disintegration and Fabric Tear. Vasc Specialist Int 2022; 38:31. [PMID: 36510690 DOI: 10.5758/vsi.220035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/29/2022] [Accepted: 10/04/2022] [Indexed: 12/15/2022] Open
Abstract
Endovascular repair of popliteal artery aneurysms (PAA) using a stent graft is suitable for patients with favorable anatomy. In the domestic situation where Gore Medical withdrew, we report two cases of unusual complications of pseudoaneurysm after endovascular repair of PAA. A 44-year-old male with a history of bypass surgery for a PAA presented with recurrent vein graft pseudoaneurysm. Endovascular treatment using a domestic stent graft was performed. However, pseudoaneurysm developed due to the graft fabric tear 1 month later, requiring surgical removal. In another case, an 84-year-old female presented with acute limb ischemia related to PAA. Endovascular aneurysm repair with the same domestic stent graft was performed. However, stent graft failure occurred 2 years later and the patient underwent open surgical repair. There was a graft fabric disintegration. When proper endovascular device is not available, open surgical treatment is the best option for treating PAA.
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Affiliation(s)
- Min-Kyu Kim
- Division of Vascular Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jun-Gon Kim
- Department of Radiology, Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Cho-Shin Kim
- Division of Transplantation and Vascular Surgery, Department of Surgery, Yeungnam University Medical Center, Daegu, Korea
| | - Kwang-Bo Park
- Department of Radiology, Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Shin-Seok Yang
- Division of Vascular Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Yang-Jin Park
- Division of Vascular Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Zhang Y, Lu Q, Zhang S, Liang Z, Cui J, Jing Z. Endovascular treatment of complicated aortic aneurysms using a modified flow-diverting strategy: Mid- to long-term outcome from a multicenter cohort study. Br J Radiol 2022; 95:20210859. [PMID: 35180007 PMCID: PMC10993961 DOI: 10.1259/bjr.20210859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 01/29/2022] [Accepted: 02/07/2022] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Frequently reported adverse events following flow-diverting stents' treatment of aortic aneurysms indicate further refinements of this technique are required. This study aims at evaluating the clinical efficacy of an improved flow-diverting strategy. METHODS A modified flow-diverting procedure was utilized in selected patients, in which stent-grafts were used to cover the non-branched segment of the aneurysmal lesion while flow-diverting multilayered bare metal stents were applied to cover the reno-visceral segment. The safety and efficacy of this joint procedure were assessed by regular follow-up. RESULTS We screened 497 patients and included 67 cases (mean age: 67.07 ± 12.14 years; 53 males) between February 2012 and March 2018. The median number of stent-grafts and bare metal stents used in the procedure were 1 (range: 1 to 3) and 3 (range: 2 to 4), respectively. During a mean follow-up period of 34.54 ± 20.28 months, aneurysm maximum diameter decreased from 64.79 ± 10.31 to 59.32 ± 10.20 mm (p = 0.002), while sac thrombosis ratio increased from 26.01±10.99% to 98.46±4.84% (p<0.001). Aneurysm-related death or conversion to open repair was documented in three patients. The majority side-branches (198/201) remained patent during follow-up. Overall clinical success rate reached 91.04% (61/67). CONCLUSIONS The joint procedure is characterized by significant aneurysm thrombosis along with high aneurysm stabilization/shrinkage and side-branches' patency rate. It might represent a potential improvement of the flow-diverting strategy in treating complex aortic lesions, yet large-scale, prospective, and randomized trials are anticipated to draw a robust conclusion. ADVANCES IN KNOWLEDGE The joint procedure could potentially exclude complex aortic aneurysms from circulation while maintaining the collateral branches.
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Affiliation(s)
- Yongxue Zhang
- Department of Vascular Surgery, Changhai
Hospital, Shanghai,
China
- Department of Interventional Radiology, Bethune International
Peace Hospital, Shijiazhuang,
China
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai
Hospital, Shanghai,
China
| | - Simeng Zhang
- Department of Pediatric Cardiac Surgery, State Key Laboratory
of Cardiovascular Disease, Fuwai Hospital,
Beijing, China
| | - Zhihui Liang
- Department of Interventional Radiology, Bethune International
Peace Hospital, Shijiazhuang,
China
| | - Jinguo Cui
- Department of Interventional Radiology, Bethune International
Peace Hospital, Shijiazhuang,
China
| | - Zaiping Jing
- Department of Vascular Surgery, Changhai
Hospital, Shanghai,
China
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Li Z, Jiang W, Diao J, Chen C, Xu K, Fan H, Yan F. Segmentary strategy in modeling of cardiovascular system with blood supply to regional skin. Biocybern Biomed Eng 2021. [DOI: 10.1016/j.bbe.2021.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sun A, Zhao C, Gao Z, Deng X, Qiu H. A proposed design of flow diverter and it’s hemodynamic validation. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2020.100049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Zhongyou L, Chong C, Yu C, Guanshi W, Wentao J. Optimization of fenestrated technique in application to aortic aneurysms with an attached branch. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2020. [DOI: 10.1016/j.medntd.2020.100037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Zhang Y, Huang Y, Teng Z, Cui J, Lu Q, Jing Z. Biomechanical insight of the stent-induced thrombosis following flow-diverting strategy in the management of complicated aortic aneurysms. INT ANGIOL 2020; 40:52-59. [PMID: 32594671 DOI: 10.23736/s0392-9590.20.04447-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The flow-diverting stent (FDS) emerges as an alternative strategy in treating complicated aortic aneurysms. However, the biomechanical behavior of the stent-induced thrombus (SIT) remains little understood. This study sought to investigate the impact of SIT on aneurysm wall stress and strain distribution and offer basic evidences for its large-scale application. METHODS Aortic aneurysms treated with FDS and followed up over 5 years were selected. Case-specific models were created based on the pre-operative and 12 months follow-up imaging. The aortic central line was generated, perpendicular to which the slice with maximum aneurysm diameter was selected for two-dimensional modeling. Pre- and post-stenting models were compared, with emphasis laid on wall stress distribution and risk factors leading to local stress concentration. Clinical follow-up data was recorded to verify the biomechanical findings. RESULTS A total of 6 cases (3 females, average age 56.3±17.2 years) were enrolled in this study. Complete sac thrombosis was documented in 5 cases at 12 months, while residual perfusion was seen in the remaining one. With the formation of SIT, the average wall tensile stress dropped from 58.60±11.11 KPa to 23.56±12.05 KPa (P=0.001) at diastolic phase, and from 88.00±15.94 KPa to 36.02±18.31 KPa (P=0.001) at systolic phase. Intra-wall calcium plaque and irregular, spontaneous intraluminal thrombus were recognized as risk factors for local stress concentration, which could be mitigated by the regular, well-organized SIT. Long-term follow-up at 5 years showed significant aneurysm shrinkage from 57.7±16.2 mm to 51.0±13.7 mm (P=0.009). CONCLUSIONS The formation of SIT after FDS implantation might protect the aneurysm by reducing the wall tensile stress and erasing the local stress concentration. Clinical follow-up data seems to support the biomechanical role of SIT, but a larger study cohort is needed. A comprehensive understanding of SIT including both biomechanical and biological perspectives is warranted to draw an exhaustive conclusion.
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Affiliation(s)
- Yongxue Zhang
- Department of Surgery, Handan Medical Center, Bethune International Peace Hospital, Handan, China.,Department of Interventional Radiology, Bethune International Peace Hospital, Shijiazhuang, China
| | - Yuan Huang
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - Zhongzhao Teng
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - Jinguo Cui
- Department of Interventional Radiology, Bethune International Peace Hospital, Shijiazhuang, China
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China -
| | - Zaiping Jing
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
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Stockle J, Romero DA, Amon CH. Optimization of porous stents for endovascular repair of abdominal aortic aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3336. [PMID: 32212322 DOI: 10.1002/cnm.3336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/21/2020] [Accepted: 03/17/2020] [Indexed: 06/10/2023]
Abstract
This study presents a simulation-based methodology to design porous stents to induce suitable hemodynamic environments inside abdominal aortic aneurysm (AAA) sacs. In the proposed methodology, an optimization algorithm iteratively modifies the porosity distribution of the stent and executes a computational fluid dynamics (CFD) simulation to determine the effect of these changes on the hemodynamic conditions inside the aneurysm sac. The optimization iterations proceed until relevant hemodynamic parameters are within ranges prescribed a priori by the user as desirable to control the progression of the AAA. The resulting porosity distribution uniquely describes the porous stent design that can control the hemodynamic environment (eg, shear stress at the aneurysm wall, pressure distribution, residence time), reducing AAA rupture risks and improving treatment efficacy. To demonstrate its potential, the proposed methodology is applied to idealized AAA geometry under steady-state flow conditions, though it may be easily applied to more complex AAA geometries under transient, pulsatile flow conditions. The proposed methodology has the potential to enable the design of a new generation of porous stents tailored to patient-specific geometries and flow conditions, to improve patient outcomes.
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Affiliation(s)
- Juan Stockle
- Escuela de Ingenieria Industrial, Universidad Diego Portales, Santiago, Chile
| | - David A Romero
- Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Cristina H Amon
- Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
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A Hypothetical Vascular Stent with Locally Enlarged Segment and the Hemodynamic Evaluation. Cardiol Res Pract 2020; 2020:7041284. [PMID: 32185077 PMCID: PMC7060871 DOI: 10.1155/2020/7041284] [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: 06/07/2019] [Accepted: 02/03/2020] [Indexed: 11/17/2022] Open
Abstract
Among the interventional stenting methods for treating coronary bifurcation lesions, the conventional treatments still have disadvantages, which include increased intervention difficulties or inadequate supply of blood flow to side branches and may alter the physiological function of downstream organs. Thus, the optimized design of stent geometry needs to be improved based on the specific shape of branches to minimize the complications of inadequate blood flow to the downstream organs and tissues. Our research used 3D modeling and fluid dynamics simulation to design and evaluate a new stent with locally enlarged segment by altering the proportion and length of enlarged surface area based on Bernoulli's equation. The aim is to increase the pressure and blood flow supply at side branches. According to series of blood flow simulations, the stent with 10% enlargement of surface area and length of 3 folders of stent diameter was assigned as the optimized design. The results revealed that by using this design, according to the simulation results, the average pressure on side branches increased at the rate of 43.6%, which would contribute to the adequate blood supply to the downstream organs. Besides, the average wall shear stress (WSS) at sidewalls increased at 9.2% while the average WSS on the host artery wall decreased at 14.1%. There is in the absent of noticeable rise in the total area of low WSS that blows the threshold of 0.5 Pa. Therefore, the present study provides a new method to optimize the hemodynamics features of stent for bifurcation arteries.
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Computational Fluid Dynamics Modeling of Hemodynamic Parameters in the Human Diseased Aorta: A Systematic Review. Ann Vasc Surg 2020; 63:336-381. [DOI: 10.1016/j.avsg.2019.04.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/09/2019] [Accepted: 04/18/2019] [Indexed: 02/07/2023]
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Dai Y, Luo G, Dai X, Liu H. Hemodynamic Effects of Multiple Overlapping Uncovered Stents on Aortic Dissection: Surgical Strategies and Implications for False Lumen Thrombosis. Cardiovasc Eng Technol 2019; 11:24-35. [PMID: 31820352 DOI: 10.1007/s13239-019-00443-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 11/20/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE Multiple overlapping uncovered stents (MOUS) are employed to promote false lumen thrombosis in the aortic dissections (AD), when the tears are in close vicinity to the branch vessels. However, the overall rate of false lumen thrombosis remains unsatisfactory. This study was performed to investigate the hemodynamic influence of MOUS on aortic dissection to shed some light on the mechanism of post-stenting false lumen thrombosis. METHODS An anatomically accurate computational fluid dynamics model was developed to investigate the hemodynamics of AD. A parametric study was carried out to demonstrate the hemodynamic influence of MOUS in various post-surgery scenarios featuring the representative surgical strategies involving MOUS. RESULTS The use of reduced-porosity MOUS slowed the blood flow in the false lumen and decreased the wall shear stress. MOUS depressed the false lumen and enlarged the true lumen, without significantly altering the blood outflow distribution among the branch vessels. Compared with MOUS-alone and stent graft-alone scenarios, the combination of MOUS and stent graft generated a substantially large region of stagnant flow. The active flow was confined to an area in close vicinity to the tears covered by the MOUS, which perfuse the right renal artery in the false lumen. CONCLUSIONS MOUS helps to generate a favored hemodynamic environment for thrombus formation in the false lumen. Application of MOUS along with covered stent grafts may represent a more effective treatment for AD than utilizing MOUS or stent graft alone.
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Affiliation(s)
- Yanan Dai
- Department of Mechanics, Tianjin University, 92 Weijin Road, Tianjin, 300072, China
| | - Guangze Luo
- Department of Surgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China
| | - Xiangchen Dai
- Department of Surgery, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin, 300052, China.
| | - Haofei Liu
- Department of Mechanics, Tianjin University, 92 Weijin Road, Tianjin, 300072, China.
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Treatment of High Surgical Risk Thoracoabdominal Aortic Aneurysms with Stent Graft and Multilayer Bare Stents Joint Technique: Mid-Long-Term Clinical Results. Ann Vasc Surg 2019; 63:108-116. [PMID: 31536795 DOI: 10.1016/j.avsg.2019.06.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 06/20/2019] [Accepted: 06/30/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND This study aims to present the performance data on stent-graft and multilayer bare stents (MBS) joint technique in the treatment of high-risk thoracoabdominal aortic aneurysm (TAAA). METHODS From May 2012 to December 2015, 8 selective TAAA cases (ages 46-75 years) ineligible for surgical repair underwent the stent-graft and MBS joint procedure, and were closely followed up for a median of 32 months (range 14-58). Using computed tomography images, the aneurysm size, luminal blood flow diameter, and the covered visceral branches were analyzed. RESULTS Technical success was achieved in all patients (100%, 8/8). Twenty-four visceral branches were covered by MBS in total. There was no complication or death during hospital stay. During follow-up period, no death or complication occurred. Aneurysm shrinkage (maximum diameter decrease ≥5 mm) was observed in 7 patients. No aneurysm expansion was observed. Total aneurysm sac thrombosis was observed in all patients. The majority of covered side branches (23/24) were successfully preserved. No visceral ischemia or bleeding complications was observed during follow-up. CONCLUSIONS Total endovascular repair of TAAA using stent-graft and MBS joint technique may be a safe and effective alternative in high surgical risk patients. More approving clinical evidences about the safety and efficacy of this procedure are anticipated.
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Wang S, Zhang Y, Feng J, Huang Y, Hui P, Gillard JH, Lu Q, Teng Z. The role of porosity and 3D cross-stent configuration of multiple overlapping uncovered stents in the management of complex aortic aneurysms – Insights from haemodynamics. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Hemodynamic analysis of a novel stent graft design with slit perforations in thoracic aortic aneurysm. J Biomech 2019; 85:210-217. [DOI: 10.1016/j.jbiomech.2019.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/08/2018] [Accepted: 01/08/2019] [Indexed: 01/11/2023]
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Ding Y, Zhongyou L, Wentao J, Yinci Z, Zhenze W, Yu C. Stent graft coverage of dual-stent strategy in the management of abdominal aortic aneurysms. Sci Rep 2018; 8:16339. [PMID: 30397213 PMCID: PMC6218544 DOI: 10.1038/s41598-018-34354-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/04/2018] [Indexed: 02/05/2023] Open
Abstract
Treating an abdominal aortic aneurysm (AAA) with a stent graft (SG) and a multilayer stent (MS) is a key technology in isolating flow fields. Clinically, dual stents (an SG in the proximal and an MS in the distal of AAA) are used for treatment of AAA, but only a few studies have examined the relationship between SG coverage and treatment effects. Through numerical simulation of the hemodynamics after SG and MS implantation, the SG coverage and position were simulated at 0% (0 mm), 25% (13.75 mm), 50% (27.5 mm), and 75% (41.25 mm). With increasing SG coverage, the pressure on the aneurysm sac wall and the flow of branch vessels gradually decreased, and the lower wall shear stress (WSS) gradually increased. The changes in pressure, lower WSS, and the mass flow rate of the branch vessels did not change significantly. The coverage of the SG has a nonsignificant effect on hemodynamics in the treatment of AAA; the implantation position need not be very precise. This research can provide theoretic support for clinicians' decision-making.
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Affiliation(s)
- Yuan Ding
- Department of Vascular Surgery of West China Hospital, Sichuan University, Chengdu, 610065, China
| | - Li Zhongyou
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Jiang Wentao
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Zhang Yinci
- School of Computer science, Sichuan University of Science and Engineering, Zigong, 643000, China
| | - Wang Zhenze
- Key Laboratory of Rehabilitation Technical Aids Technology and System of the Ministry of Civil Affairs & Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, 100176, China
| | - Chen Yu
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China.
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Dai HL, Guang XF, Lu YB, Xue Q, Zhang WH. Multiple Overlapping Stents Might Be a Promising Therapeutic Target for Coronary Artery Aneurysms. JACC Cardiovasc Interv 2018; 11:2234-2235. [DOI: 10.1016/j.jcin.2018.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 08/14/2018] [Indexed: 10/27/2022]
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Zhongyou L, Wentao J, Ding Y, Yu C, Xiaobao T, Zhihong Z. Investigation of the hemodynamics of a juxtarenal aortic aneurysm with intervention by dual-stents strategy. Clin Biomech (Bristol, Avon) 2018; 58:109-115. [PMID: 30075422 DOI: 10.1016/j.clinbiomech.2018.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/24/2018] [Accepted: 07/28/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To study the feasibility of using two stents (a combination of multilayer stent [MS] and stent graft [SG]) in the treatment of a juxtarenal aortic aneurysm that involves a significant branch artery and to determine the advantages and disadvantages of using SGs upstream and downstream from the aneurysm so as to provide some theoretical guidance for preoperative clinical decision-making in the future. METHODS Four ideal geometric models were established for numerical computation: case 1 refers to an aneurysm without the use of stents, case 2 represents the implantation of two MSs in an aneurysm, and case 3 (SG + MS) and case 4 (MS + SG) both involve the treatment of an aneurysm by using a combination of SG and MG. RESULTS The aneurysm pressure is slightly lower and there are more vortices when the SG is implanted (case 3 and case 4). In particular, for case 4, additional vortices appear in the sac and the area of the low-wall shear stress is larger on the aneurysm compared with those of the other three cases. However, the pressure becomes uneven, and a peak pressure region is observed on the wall of the aneurysm, and therefore, the aneurysmal wall will become buckled. In addition, the flux of the renal artery in the four cases is greater than that in the normal case. CONCLUSION The arrangements in cases 3 and 4 can effectively isolate the aneurysm from circulation, but clinically, it is necessary to avoid such a high-risk situation wherein the SG is positioned downstream of the aneurysm (case 4), even though this leads to improved isolation.
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Affiliation(s)
- Li Zhongyou
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Jiang Wentao
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yuan Ding
- Department of Vascular Surgery of West China Hospital, Sichuan University, Chengdu 610065, China
| | - Chen Yu
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China.
| | - Tian Xiaobao
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China.
| | - Zhou Zhihong
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China.
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Li Z, Yan F, Yang J, Chen Y, Xu Z, Jiang W, Yuan D. Hemodynamics and Oxygen Transport through Pararenal Aortic Aneurysm Treated with Multilayer Stent: A Numerical Study. Ann Vasc Surg 2018; 54:290-297. [PMID: 30081175 DOI: 10.1016/j.avsg.2018.05.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 05/14/2018] [Accepted: 05/28/2018] [Indexed: 02/05/2023]
Abstract
BACKGROUND As opposed to an endoluminal stent graft, a multilayer stent (MS) consists of a porous mesh, which allows for the possibility of treating pararenal aortic aneurysms (PRAAs) that involve a significant branch vessel. However, the choice of the density of the MS plays a vital role in isolating the aneurysm and allowing unobstructed blood flow in the branch vessel. METHOD In the present study, we examined 3 cases (without a stent and with single-layer and double-layer stents) via numerical simulations to explore the feasibility of the MSs used in the treatment of such aneurysms and estimate whether there is a more appropriate or optimal stent density. RESULTS With stent intervention, the velocity of blood flow in the sac decreased, but the pressure on the surface of the aneurysm did not decrease although it became more uniform. In addition, the "region of double low" (with low wall shear stress and a low Sherwood number) enlarged after stent implantation. Even with the double-layer stent, however, the flux of the branch vessel was still above normal, and we could predict that the optimal stent porosity was approximately 49.9%. CONCLUSIONS Unlike in previous studies, an MS could not be feasibly applied to high-risk PRAAs. However, an MS can induce sac thrombosis in the later stages while maintaining visceral vessel patency, and our results suggest that the optimal stent may be a 4-layer stent.
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Affiliation(s)
- Zhongyou Li
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Fei Yan
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Jingru Yang
- School of Manufacturing Science & Engineering, Sichuan University, Chengdu, China
| | - Yu Chen
- Department of Applied Mechanics, Sichuan University, Chengdu, China.
| | - Zhizhi Xu
- Department of Applied Mechanics, Sichuan University, Chengdu, China
| | - Wentao Jiang
- Department of Applied Mechanics, Sichuan University, Chengdu, China.
| | - Ding Yuan
- Department of Vascular Surgery of West China Hospital, Sichuan University, Chengdu, China
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Yeow SL, Leo HL. Is Multiple Overlapping Uncovered Stents Technique Suitable for Aortic Aneurysm Repair? Artif Organs 2017; 42:174-183. [DOI: 10.1111/aor.12993] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/23/2017] [Accepted: 06/14/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Siang Lin Yeow
- Division of Research; Singapore General Hospital; Singapore
- Biomedical Engineering; National University of Singapore; Singapore
| | - Hwa Liang Leo
- Biomedical Engineering; National University of Singapore; Singapore
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Influence of overlapping pattern of multiple overlapping uncovered stents on the local mechanical environment: A patient-specific parameter study. J Biomech 2017; 60:188-196. [PMID: 28712543 DOI: 10.1016/j.jbiomech.2017.06.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 06/05/2017] [Accepted: 06/25/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND Multiple overlapping uncovered stents (MOUS) system has shown potentials in managing complex aortic aneurysms with side branches involvement. It promotes the development of thrombus by modulating local flow pattern that reduces the wall tension, while maintaining patency of side branches. However the modulation of local hemodynamic parameters depends on various factors that have not been assessed comprehensively. METHODS Aneurysm 3D geometry was reconstructed based on CT images. One-way fluid-structure interaction analysis was performed to quantify structural stress concentration in the wall, and changes of blood velocity, wall shear stress (WSS), oscillatory shear index (OSI), relative residence time (RRT) and pressure in the sac due to the stent deployment. RESULTS High structural stress concentration due to stent deployment was found in the landing zone and it increased linearly with the number of stents deployed. The wall tension in the sac was unaffected by the stent deployment. Stress within the wall was insensitive to the different overlapping pattern. After one stent was deployed, the mean flow velocity in the sac reduced by 36.4%. The deployment of the 2nd stent further reduced the mean sac velocity by 10%. WSS decreased while both OSI and RRT increased after stent deployment, however pressure in the sac remained nearly unchanged. Except for the cases with complete stents struts alignment, different overlapping pattern had little effect on flow parameters. CONCLUSIONS Mechanical parameters modulated by the MOUS are insensitive to different overlapping pattern suggesting that endovascular procedure can be performed with less attention to the overlapping pattern.
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Xu J, Yang J, Sohrabi S, Zhou Y, Liu Y. Finite Element Analysis of the Implantation Process of Overlapping Stents. J Med Device 2017; 11:0210101-210109. [PMID: 28690712 DOI: 10.1115/1.4036391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 03/15/2017] [Indexed: 11/08/2022] Open
Abstract
Overlapping stents are widely used in vascular stent surgeries. However, the rate of stent fractures (SF) and in-stent restenosis (ISR) after using overlapping stents is higher than that of single stent implantations. Published studies investigating the nature of overlapping stents rely primarily on medical images, which can only reveal the effect of the surgery without providing insights into how stent overlap influences the implantation process. In this paper, a finite element analysis of the overlapping stent implantation process was performed to study the interaction between overlapping stents. Four different cases, based on three typical stent overlap modes and two classical balloons, were investigated. The results showed that overlapping contact patterns among struts were edge-to-edge, edge-to-surface, and noncontact. These were mainly induced by the nonuniform deformation of the stent in the radial direction and stent tubular structures. Meanwhile, the results also revealed that the contact pressure was concentrated in the edge of overlapping struts. During the stent overlap process, the contact pattern was primarily edge-to-edge contact at the beginning and edge-to-surface contact as the contact pressure increased. The interactions between overlapping stents suggest that the failure of overlapping stents frequently occurs along stent edges, which agrees with the previous experimental research regarding the safety of overlapping stents. This paper also provides a fundamental understanding of the mechanical properties of overlapping stents.
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Affiliation(s)
- Jiang Xu
- School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China e-mail:
| | - Jie Yang
- School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China e-mail:
| | - Salman Sohrabi
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015 e-mail:
| | - Yihua Zhou
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015 e-mail:
| | - Yaling Liu
- Bioengineering Program, Lehigh University, Bethlehem, PA 18015
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22
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Xiong Y, Wang X, Jiang W, Tian X, Wang Q, Fan Y, Chen Y. Hemodynamics study of a multilayer stent for the treatment of aneurysms. Biomed Eng Online 2016; 15:134. [PMID: 28155682 PMCID: PMC5260060 DOI: 10.1186/s12938-016-0248-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background The changes of hemodynamics caused by the implantation of multilayer stent (MS) have significant effects for aneurysm sac. Methods Comparisons of 3D numerical models with/without a MS in an abdominal aortic aneurysm with a 90° branch vessel were numerically studied from the viewpoint of hemodynamics. Results The results showed that: (1) The flow fields and Wall Shear Stress (WSS) are changed dramatically after MS implantation. The velocity of the blood flow in aneurysm sac decreases significantly and the regions of low-WSS increase. These help thrombus formation; (2) The pressure in aneurysm slightly decreases and keeps close to the normal level of blood pressure, however the risk of aneurysm enlargement or even rupture still exists; (3) The flux and the velocity in branch artery are reduced by about half after MS implantation. Due to the implantation of MS, the changes in the flow field causes the decrease of pressure/WSS in aneurysm sac and the blood flow in branch vessel. Conclusions The implantation of MS into abdominal artery results in more low-WSS regions inside aneurysm which induces thrombus formation. The pressure is reduced slightly means the risk of aneurysm rupture exists.
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Affiliation(s)
- Yan Xiong
- School of Manufacturing Science and Engineering, Sichuan University, 610065, Chengdu, China
| | - Xuhong Wang
- Department of Applied Mechanics, Sichuan University, 610065, Chengdu, China
| | - Wentao Jiang
- Department of Applied Mechanics, Sichuan University, 610065, Chengdu, China.
| | - Xiaobao Tian
- Department of Applied Mechanics, Sichuan University, 610065, Chengdu, China
| | - Qingyuan Wang
- Department of Applied Mechanics, Sichuan University, 610065, Chengdu, China
| | - Yubo Fan
- School of Biological Science and Medical Engineering, Beihang University, 100191, Beijing, China
| | - Yu Chen
- Department of Applied Mechanics, Sichuan University, 610065, Chengdu, China.
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Hemodynamic Study of Flow Remodeling Stent Graft for the Treatment of Highly Angulated Abdominal Aortic Aneurysm. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:3830123. [PMID: 27247612 PMCID: PMC4876205 DOI: 10.1155/2016/3830123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/30/2016] [Accepted: 04/17/2016] [Indexed: 11/18/2022]
Abstract
This study investigates the effect of a novel flow remodeling stent graft (FRSG) on the hemodynamic characteristics in highly angulated abdominal aortic aneurysm based on computational fluid dynamics (CFD) approach. An idealized aortic aneurysm with varying aortic neck angulations was constructed and CFD simulations were performed on nonstented models and stented models with FRSG. The influence of FRSG intervention on the hemodynamic performance is analyzed and compared in terms of flow patterns, wall shear stress (WSS), and pressure distribution in the aneurysm. The findings showed that aortic neck angulations significantly influence the velocity flow field in nonstented models, with larger angulations shifting the mainstream blood flow towards the center of the aorta. By introducing FRSG treatment into the aneurysm, erratic flow recirculation pattern in the aneurysm sac diminishes while the average velocity magnitude in the aneurysm sac was reduced in the range of 39% to 53%. FRSG intervention protects the aneurysm against the impacts of high velocity concentrated flow and decreases wall shear stress by more than 50%. The simulation results highlighted that FRSG may effectively treat aneurysm with high aortic neck angulations via the mechanism of promoting thrombus formation and subsequently led to the resorption of the aneurysm.
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The hydrodynamic basis of the vacuum cleaner effect in continuous-flow PCNL instruments: an empiric approach and mathematical model. World J Urol 2015; 34:717-24. [DOI: 10.1007/s00345-015-1682-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022] Open
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Zhang P, Liu X, Sun A, Fan Y, Deng X. Hemodynamic insight into overlapping bare-metal stents strategy in the treatment of aortic aneurysm. J Biomech 2015; 48:2041-6. [PMID: 25911250 DOI: 10.1016/j.jbiomech.2015.03.028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 03/18/2015] [Accepted: 03/22/2015] [Indexed: 10/23/2022]
Abstract
Clinical trials have shown overlapping bare-metal stents provoke effective thrombus clot within the aneurysm sac and shrinkage of the aneurysm by directly regulating the hemodynamics. To gain insight into the hemodynamic mechanism of the technique, three cases of simplified thoracic aortic aneurysm models (with no stent, a single stent and two overlapped stents deployed within the aneurysm sac) were studied and compared in terms of time-varying velocity and shear rate, time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and relative residence time (RRT). The results demonstrated that the overlapping stents' strategy was more effective in reducing the velocity of blood flow within the aneurysm, especially for the area near the aneurysm wall. Stenting induced a dramatic change trend of shear rate during the cardiac cycle, in which a very high shear rate (>10,000 s(-1)) during the systole and a quite low shear rate (<1000 s(-1)) during the diastole were observed, respectively. Moreover, reduced TAWSS and OSI and elevated RRT values were observed on the aneurysm wall after stent placement. The effects of stenting on the shear rate, TAWSS, OSI and RRT in the aneurysm would be significantly enhanced by two overlapped stents. The present findings therefore indicated that, the overlapping bare-metal stents can isolate the aneurysm effectively and may create a favorable hemodynamic environment provoking platelets activation and aggregation within the aneurysm, which may promote thrombus formation/growth there, hence contribute to degradation of the aneurysm.
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Affiliation(s)
- Peng Zhang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Xiao Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
| | - Anqiang Sun
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
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