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Govindarajan V, Wanna C, Johnson NP, Kolanjiyil AV, Kim H, Kitkungvan D, McPherson DM, Grande-Allen J, Chandran KB, Estrera A, Ramzy D, Prakash S. Unraveling aortic hemodynamics using fluid structure interaction: biomechanical insights into bicuspid aortic valve dynamics with multiple aortic lesions. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01892-w. [PMID: 39365514 DOI: 10.1007/s10237-024-01892-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 09/22/2024] [Indexed: 10/05/2024]
Abstract
Aortic lesions, exemplified by bicuspid aortic valves (BAVs), can complicate congenital heart defects, particularly in Turner syndrome patients. The combination of BAV, dilated ascending aorta, and an elongated aortic arch presents complex hemodynamics, requiring detailed analysis for tailored treatment strategies. While current clinical decision-making relies on imaging modalities offering limited biomechanical insights, integrating high-performance computing and fluid-structure interaction algorithms with patient data enables comprehensive evaluation of diseased anatomy and planned intervention. In this study, a patient-specific workflow was utilized to biomechanically assess a Turner syndrome patient's BAV, dilated ascending aorta, and elongated arch. Results showed significant improvements in valve function (effective orifice area, EOA increased approximately twofold) and reduction in valve stress (~ 1.8-fold) following virtual commissurotomy, leading to enhanced flow dynamics and decreased viscous dissipation (~ twofold) particularly in the ascending aorta. However, increased viscous dissipation in the distal transverse aortic arch offset its local reduction in the AAo post-intervention, emphasizing the elongated arch's role in aortic hemodynamics. Our findings highlight the importance of comprehensive biomechanical evaluation and integrating patient-specific modeling with conventional imaging techniques for improved disease assessment, risk stratification, and treatment planning, ultimately enhancing patient outcomes.
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Affiliation(s)
- Vijay Govindarajan
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA.
- Boston Children's Hospital, Boston, MA, USA.
- Harvard Medical School, Boston, MA, USA.
| | - Charles Wanna
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
| | - Nils P Johnson
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
| | | | | | - Danai Kitkungvan
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
| | - David M McPherson
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
| | | | - Krishnan B Chandran
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
- The University of Iowa, Iowa City, IA, USA
| | - Antony Estrera
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
| | - Danny Ramzy
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
| | - Siddharth Prakash
- Division of Cardiology, Department of Internal Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, 1881 East Road, Houston, TX, 77054, USA
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Zheng HJ, Cheng YB, Lin DQ, Yan CJ, Yu SJ, He P, Li J, Cheng W. Effect of transcatheter aortic valve replacement on ascending aorta dilatation rate in patients with tricuspid and bicuspid aortic stenosis. IJC HEART & VASCULATURE 2023; 49:101313. [PMID: 38107428 PMCID: PMC10724657 DOI: 10.1016/j.ijcha.2023.101313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/07/2023] [Accepted: 11/20/2023] [Indexed: 12/19/2023]
Abstract
Objectives The aim of the present study was to assess the differences between BAV and TAV patients with chronic moderate to severe or severe AS regarding presentation, incidence of TAVR, survival, ascending aorta diameter and dilatation rate before and after TAVR. Methods The study included 667 consecutive patients with chronic moderate to severe or severe AS from January 2012 and December 2022. Outcomes included all-cause mortality, incidence of TAVR, and ascending aorta diameter and dilatation rate. Results There were 185 BAV-AS and 482 TAV-AS patients, and BAV-AS patients were younger (67 vs 78 years, P = 0.027). Total follow-up was 4.5 years (IQR: 2.7-8.9 years), 290 patients underwent TAVR, and 165 patients died. The 8-year TAVR incidence was higher in BAV-AS (55% ± 4%) vs TAV-AS (41% ± 5%; P = 0.02). The 8-year survival was higher in BAV-AS (85% ± 6%) vs TAV-AS (71% ± 6%; P < 0.0001) and became insignificant after age adjustment (P = 0.33). The dilatation rate of ascending aorta was significantly faster in BAV-AS patients compared with TAV-AS patients before TAVR. However, the ascending aorta dilatation rate for BAV-AS and TAV-AS patients was not significantly different after TAVR. Conclusions Compared with TAV-AS, BAV-AS patients were younger and underwent TAVR more frequently, resulting in a considerable survival advantage. After TAVR, ascending aorta dilatation rates were similar in BAV-AS and TAV-AS patients, suggesting an important role of hemodynamics on ascending aorta dilatation in BAV-AS.
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Affiliation(s)
| | | | - De-Qing Lin
- Department of Cardiac Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Chao-Jun Yan
- Department of Cardiac Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - San-Jiu Yu
- Department of Cardiac Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Ping He
- Department of Cardiac Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Jun Li
- Department of Cardiac Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Wei Cheng
- Department of Cardiac Surgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
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Kara R, Vergara C. Assessing turbulent effects in ascending aorta in presence of bicuspid aortic valve. Comput Methods Biomech Biomed Engin 2023:1-13. [PMID: 37950490 DOI: 10.1080/10255842.2023.2279938] [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: 01/25/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023]
Abstract
Aortic valves with bicuspids have two rather than three leaflets, which is a congenital heart condition. About 0.5-2% of people have a bicuspid aortic valve. Blood flow through the aorta is commonly believed to be laminar, although aortic valve disorders can cause turbulent transitions. Understanding the impact of turbulence is crucial for foreseeing how the disease will progress. The study's objective was use large eddy simulation to provide a thorough analysis of the turbulence in bicuspid aortic valve dysfunction. Using a large eddy simulation, the blood flow patterns of the bicuspid and tricuspid aortic valves were compared, and significant discrepancies were found. The velocity field in flow in bicuspid configurations was asymmetrically distributed toward the ascending aorta. In tricuspid aortic valve (TAV) the flow, on the other hand, was symmetrical within the same aortic segment. Moreover, we looked into standard deviation, Q-criterion, viscosity ratio and wall shear stresses for each cases to understand transition to turbulence. Our findings indicate that in the bicuspid aortic valve (BAV) case, the fluid-dynamic abnormalities increase. The global turbulent kinetic energy and time-averaged wall shear stress for the TAV and BAV scenarios were also examined. We discovered that the global turbulent kinetic energy was higher in the BAV case compared to TAV, in addition to the increased wall shear stress induced by the BAV in the ascending aorta.
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Affiliation(s)
- Rukiye Kara
- Department of Mathematics, Mimar Sinan Fine Arts University, Istanbul, Turkey
| | - Christian Vergara
- LABS - Dipartimento di Chimica, Materiali e Ingegneria Chimica" Giulio Natta" - Politecnico di Milano, Milan, Italy
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Geronzi L, Bel-Brunon A, Martinez A, Rochette M, Sensale M, Bouchot O, Lalande A, Lin S, Valentini PP, Biancolini ME. Calibration of the Mechanical Boundary Conditions for a Patient-Specific Thoracic Aorta Model Including the Heart Motion Effect. IEEE Trans Biomed Eng 2023; 70:3248-3259. [PMID: 37390004 DOI: 10.1109/tbme.2023.3287680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
OBJECTIVE We propose a procedure for calibrating 4 parameters governing the mechanical boundary conditions (BCs) of a thoracic aorta (TA) model derived from one patient with ascending aortic aneurysm. The BCs reproduce the visco-elastic structural support provided by the soft tissue and the spine and allow for the inclusion of the heart motion effect. METHODS We first segment the TA from magnetic resonance imaging (MRI) angiography and derive the heart motion by tracking the aortic annulus from cine-MRI. A rigid-wall fluid-dynamic simulation is performed to derive the time-varying wall pressure field. We build the finite element model considering patient-specific material properties and imposing the derived pressure field and the motion at the annulus boundary. The calibration, which involves the zero-pressure state computation, is based on purely structural simulations. After obtaining the vessel boundaries from the cine-MRI sequences, an iterative procedure is performed to minimize the distance between them and the corresponding boundaries derived from the deformed structural model. A strongly-coupled fluid-structure interaction (FSI) analysis is finally performed with the tuned parameters and compared to the purely structural simulation. RESULTS AND CONCLUSION The calibration with structural simulations allows to reduce maximum and mean distances between image-derived and simulation-derived boundaries from 8.64 mm to 6.37 mm and from 2.24 mm to 1.83 mm, respectively. The maximum root mean square error between the deformed structural and FSI surface meshes is 0.19 mm. This procedure may prove crucial for increasing the model fidelity in replicating the real aortic root kinematics.
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Fatehi Hassanabad A, King MA, Di Martino E, Fedak PWM, Garcia J. Clinical implications of the biomechanics of bicuspid aortic valve and bicuspid aortopathy. Front Cardiovasc Med 2022; 9:922353. [PMID: 36035900 PMCID: PMC9411999 DOI: 10.3389/fcvm.2022.922353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 07/25/2022] [Indexed: 11/27/2022] Open
Abstract
Bicuspid aortic valve (BAV), which affects up to 2% of the general population, results from the abnormal fusion of the cusps of the aortic valve. Patients with BAV are at a higher risk for developing aortic dilatation, a condition known as bicuspid aortopathy, which is associated with potentially life-threatening sequelae such as aortic dissection and aortic rupture. Although BAV biomechanics have been shown to contribute to aortopathy, their precise impact is yet to be delineated. Herein, we present the latest literature related to BAV biomechanics. We present the most recent definitions and classifications for BAV. We also summarize the current evidence pertaining to the mechanisms that drive bicuspid aortopathy. We highlight how aberrant flow patterns can contribute to the development of aortic dilatation. Finally, we discuss the role cardiac magnetic resonance imaging can have in assessing and managing patient with BAV and bicuspid aortopathy.
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Affiliation(s)
- Ali Fatehi Hassanabad
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, Calgary, AB, Canada
| | - Melissa A. King
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, Calgary, AB, Canada
| | - Elena Di Martino
- Department of Civil Engineering, University of Calgary, Calgary, AB, Canada
- Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
- Centre for Bioengineering Research and Education, University of Calgary, Calgary, AB, Canada
| | - Paul W. M. Fedak
- Section of Cardiac Surgery, Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, Calgary, AB, Canada
| | - Julio Garcia
- Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, Calgary, AB, Canada
- Department of Radiology, University of Calgary, Calgary, AB, Canada
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Julio Garcia
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Hou Q, Tao K, Du T, Wei H, Zhang H, Chen S, Pan Y, Qiao A. A computational analysis of potential aortic dilation induced by the hemodynamic effects of bicuspid aortic valve phenotypes. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 220:106811. [PMID: 35447428 DOI: 10.1016/j.cmpb.2022.106811] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/01/2022] [Accepted: 04/10/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVES The bicuspid aortic valve (BAV) is a major risk factor for the progression of aortic dilation (AD) because of the induced abnormal blood flow environment in aorta. The differences in the development of AD induced by BAV phenotypes remains unclear. Therefore, the objective of this study was to assess the potential locations of AD induced by different phenotypes of BAV. The different effects of opening orifice area and leaflet orientation on ascending aortic hemodynamics in Type-1 BAV was investigated by means of numerical simulation. METHODS Finite element dynamic analysis was performed on tricuspid aortic valve (TAV) and BAV models to simulate the motion of the leaflets and obtain the geometrical characteristics of AV at peak systole as a reference, which were used for aortic models. Then, four sets of aortic fluid models were designed according to the leaflet fusion types [TAV; BAV (left-right-coronary cusp fusion, LR; right-non-coronary cusp fusion, RN; left-non-coronary cusp fusion, LN)], and the computational fluid dynamics method was applied to compare the hemodynamic differences within the aorta at peak systole. RESULTS The maximum opening area of BAV was significantly reduced, resulting in alterations in aortic hemodynamics compared with TAV. The velocity streamlines were essentially parallel to the aortic wall in TAV. The average pressure and wall shear stress in aorta tend to be stable. In contrary, the eccentricity of BAV orifice jet resulted in high-velocity flow directed toward the ascending aorta (AA) wall and aortic arch for LR and LN; RN features an asymmetrical velocity distribution toward the outer bend of the middle AA, and eccentric flow tends to impact the distal AA. As the flow angle is associated with distinct flow impingement locations, different degrees of WSS and pressure concentration occur along the aortic wall from the AA to the aortic arch in three BAV types. CONCLUSIONS The BAV morphotype affects the aortic hemodynamics, and the abnormal blood flow associated with BAV may play a role in AD. The different BAV phenotypes determine the direction of blood flow jet and change the expression of dilation. LR is likely to cause dilation of the tubular AA; RN results in dilation of the middle AA to proximal aortic arch; and LN causes an increased incidence of the tubular AA and the proximal aortic arch.
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Affiliation(s)
- Qianwen Hou
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Keyi Tao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Tianming Du
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China.
| | - Hongge Wei
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Honghui Zhang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Shiliang Chen
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Youlian Pan
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China
| | - Aike Qiao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China; Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing, China.
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Qiao Y, Mao L, Ding Y, Zhu T, Luo K, Fan J. Fluid-structure interaction: Insights into biomechanical implications of endograft after thoracic endovascular aortic repair. Comput Biol Med 2021; 138:104882. [PMID: 34600328 DOI: 10.1016/j.compbiomed.2021.104882] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/04/2021] [Accepted: 09/19/2021] [Indexed: 10/20/2022]
Abstract
Thoracic endovascular aortic repair (TEVAR) has developed to be the most effective treatment for aortic diseases. This study aims to evaluate the biomechanical implications of the implanted endograft after TEVAR. We present a novel image-based, patient-specific, fluid-structure computational framework. The geometries of blood, endograft, and aortic wall were reconstructed based on clinical images. Patient-specific measurement data was collected to determine the parameters of the three-element Windkessel. We designed three postoperative scenarios with rigid wall assumption, blood-wall interaction, blood-endograft-wall interplay, respectively, where a two-way fluid-structure interaction (FSI) method was applied to predict the deformation of the composite stent-wall. Computational results were validated with Doppler ultrasound data. Results show that the rigid wall assumption fails to predict the waveforms of blood outflow and energy loss (EL). The complete storage and release process of blood flow energy, which consists of four phases is captured by the FSI method. The endograft implantation would weaken the buffer function of the aorta and reduce mean EL by 19.1%. The closed curve area of wall pressure and aortic volume could indicate the EL caused by the interaction between blood flow and wall deformation, which accounts for 68.8% of the total EL. Both the FSI and endograft have a slight effect on wall shear stress-related-indices. The deformability of the composite stent-wall region is remarkably limited by the endograft. Our results highlight the importance of considering the interaction between blood flow, the implanted endograft, and the aortic wall to acquire physiologically accurate hemodynamics in post-TEVAR computational studies and the deformation of the aortic wall is responsible for the major EL of the blood flow.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Le Mao
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ying Ding
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
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Yan W, Li J, Wang W, Wei L, Wang S. A Fluid-Structure Interaction Study of Different Bicuspid Aortic Valve Phenotypes Throughout the Cardiac Cycle. Front Physiol 2021; 12:716015. [PMID: 34381379 PMCID: PMC8350765 DOI: 10.3389/fphys.2021.716015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
The bicuspid aortic valve (BAV) is a congenital malformation of the aortic valve with a variety of structural features. The current research on BAV mainly focuses on the systolic phase, while ignoring the diastolic hemodynamic characteristics and valve mechanics. The purpose of this study is to compare the differences in hemodynamics and mechanical properties of BAV with different phenotypes throughout the cardiac cycle by means of numerical simulation. Based on physiological anatomy, we established an idealized tricuspid aortic valve (TAV) model and six phenotypes of BAV models (including Type 0 a-p, Type 0 lat, Type 1 L-R, Type 1 N-L, Type 1 R-N, and Type 2), and simulated the dynamic changes of the aortic valve during the cardiac cycle using the fluid-structure interaction method. The morphology of the leaflets, hemodynamic parameters, flow patterns, and strain were analyzed. Compared with TAV, the cardiac output and effective orifice area of different BAV phenotypes decreased certain degree, along with the peak velocity and mean pressure difference increased both. Among all BAV models, Type 2 exhibited the worst hemodynamic performance. During the systole, obvious asymmetric flow field was observed in BAV aorta, which was related to the orientation of BAV. Higher strain was generated in diastole for BAV models. The findings of this study suggests specific differences in the hemodynamic characteristics and valve mechanics of different BAV phenotypes, including different severity of stenosis, flow patterns, and leaflet strain, which may be critical for prediction of other subsequent aortic diseases and differential treatment strategy for certain BAV phenotype.
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Affiliation(s)
- Wentao Yan
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Jianming Li
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Wenshuo Wang
- Department of Vascular Surgery, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China
| | - Lai Wei
- Department of Vascular Surgery, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China
| | - Shengzhang Wang
- Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
- Institute of Biomedical Engineering Technology, Academy for Engineering and Technology, Fudan University, Shanghai, China
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9
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Kuchumov AG, Vedeneev V, Samartsev V, Khairulin A, Ivanov O. Patient-specific fluid-structure interaction model of bile flow: comparison between 1-way and 2-way algorithms. Comput Methods Biomech Biomed Engin 2021; 24:1693-1717. [PMID: 34176396 DOI: 10.1080/10255842.2021.1910942] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Gallbladder disease is one of the most spread pathologies in the world. Despite the number of operations dealing with biliary surgery increases, the number of postoperative complications is also high. The aim of this study is to show the influence of the biliary system pathology on bile flow character and to numerically assess the effect of surgical operation (cholecystectomy) on the fluid dynamics in the extrahepatic biliary tree, and also to reveal the difference between 1-way and 2-way FSI algorithms on the results. Moreover, the bile viscosity and biliary tree geometry influence on the choledynamics were evaluated. Bile velocity, pressure, wall shear stress (WSS), displacements and von Mises stress distributions in the extrahepatic biliary tree are presented, and comparison is made between a healthy and a lithogenic bile. The patient-specific biliary tree model is created using magnetic resonance imaging (MRI) and imported in a commercial finite element analysis software. It is found that in the case of lithogenic bile, velocities have lower magnitude while pressures are higher. Furthermore, stress analysis of the bile ducts shows that the WSS distribution is found mostly prevailing in the common hepatic duct and common bile duct areas. It is shown that when it is necessary to evaluate the bile flow dynamics in urgent medical situations, 1-way analysis is acceptable. Nevertheless, 2-way FSI provides more accurate data, if necessary to evaluate the stress-strain state of bile ducts. The proposed model can be applied to medical practice to reduce the number of post-operative complications.
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Affiliation(s)
- Alex G Kuchumov
- Department of Computational Mathematics, Mechanics, and Biomechanics, Perm National Research Polytechnic University, Perm, Russian Federation.,Mathematical Center, Kazan Federal University, Kazan, Russian Federation
| | - Vasily Vedeneev
- Steklov Mathematical Institute of Russian Academy of Sciences, Moscow, Russian Federation.,Institute of Mechanics, Moscow, Russian Federation
| | - Vladimir Samartsev
- Department of General Surgery, Perm State Medical University, Perm, Russian Federation
| | - Aleksandr Khairulin
- Department of Computational Mathematics, Mechanics, and Biomechanics, Perm National Research Polytechnic University, Perm, Russian Federation
| | - Oleg Ivanov
- Institute of Mechanics of Moscow State University, Moscow, Russian Federation
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10
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de Oliveira DC, Owen DG, Qian S, Green NC, Espino DM, Shepherd DET. Computational fluid dynamics of the right atrium: Assessment of modelling criteria for the evaluation of dialysis catheters. PLoS One 2021; 16:e0247438. [PMID: 33630903 PMCID: PMC7906423 DOI: 10.1371/journal.pone.0247438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 02/06/2021] [Indexed: 11/19/2022] Open
Abstract
Central venous catheters are widely used in haemodialysis therapy, having to respect design requirements for appropriate performance. These are placed within the right atrium (RA); however, there is no prior computational study assessing different catheter designs while mimicking their native environment. Here, a computational fluid dynamics model of the RA, based on realistic geometry and transient physiological boundary conditions, was developed and validated. Symmetric, split and step catheter designs were virtually placed in the RA and their performance was evaluated by: assessing their interaction with the RA haemodynamic environment through prediction of flow vorticity and wall shear stress (WSS) magnitudes (1); and quantifying recirculation and tip shear stress (2). Haemodynamic predictions from our RA model showed good agreement with the literature. Catheter placement in the RA increased average vorticity, which could indicate alterations of normal blood flow, and altered WSS magnitudes and distribution, which could indicate changes in tissue mechanical properties. All designs had recirculation and elevated shear stress values, which can induce platelet activation and subsequently thrombosis. The symmetric design, however, had the lowest associated values (best performance), while step design catheters working in reverse mode were associated with worsened performance. Different tip placements also impacted on catheter performance. Our findings suggest that using a realistically anatomical RA model to study catheter performance and interaction with the haemodynamic environment is crucial, and that care needs to be given to correct tip placement within the RA for improved recirculation percentages and diminished shear stress values.
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Affiliation(s)
- Diana C. de Oliveira
- Department of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - David G. Owen
- Department of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Shuang Qian
- Department of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Naomi C. Green
- Department of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Daniel M. Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Duncan E. T. Shepherd
- Department of Mechanical Engineering, University of Birmingham, Birmingham, United Kingdom
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11
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de Oliveira DMC, Abdullah N, Green NC, Espino DM. Biomechanical Assessment of Bicuspid Aortic Valve Phenotypes: A Fluid-Structure Interaction Modelling Approach. Cardiovasc Eng Technol 2020; 11:431-447. [PMID: 32519086 DOI: 10.1007/s13239-020-00469-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/04/2020] [Indexed: 12/11/2022]
Abstract
PURPOSE Bicuspid aortic valve (BAV) is a congenital heart malformation with phenotypic heterogeneity. There is no prior computational study that assesses the haemodynamic and valve mechanics associated with BAV type 2 against a healthy tricuspid aortic valve (TAV) and other BAV categories. METHODS A proof-of-concept study incorporating three-dimensional fluid-structure interaction (FSI) models with idealised geometries (one TAV and six BAVs, namely type 0 with lateral and anterior-posterior orientations, type 1 with R-L, N-R and N-L leaflet fusion and type 2) has been developed. Transient physiological boundary conditions have been applied and simulations were run using an Arbitrary Lagrangian-Eulerian formulation. RESULTS Our results showed the presence of abnormal haemodynamics in the aorta and abnormal valve mechanics: type 0 BAVs yielded the best haemodynamical and mechanical outcomes, but cusp stress distribution varied with valve orifice orientation, which can be linked to different cusp calcification location onset; type 1 BAVs gave rise to similar haemodynamics and valve mechanics, regardless of raphe position, but this position altered the location of abnormal haemodynamic features; finally, type 2 BAV constricted the majority of blood flow, exhibiting the most damaging haemodynamic and mechanical repercussions when compared to other BAV phenotypes. CONCLUSION The findings of this proof-of-concept work suggest that there are specific differences across haemodynamics and valve mechanics associated with BAV phenotypes, which may be critical to subsequent processes associated with their pathophysiology processes.
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Affiliation(s)
- Diana M C de Oliveira
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Nazirul Abdullah
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Naomi C Green
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - Daniel M Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
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OLIVEIRA DIANAC, LARANJO SÉRGIO, TIAGO JORGE, PINTO FÁTIMAF, SEQUEIRA ADÉLIA. NUMERICAL SIMULATION OF DILATION PATTERNS OF THE ASCENDING AORTA IN AORTOPATHIES. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519419500684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Aortic dilation is associated with congenital bicuspid aortic valve (BAV) disease, and its etiology is still not completely understood. The aim of this study is to provide further insight into aortic hemodynamics in a BAV population with different degrees of aortic dilation and regurgitation in comparison with a patient without pathology. A fluid–structure interaction (FSI) numerical approach is implemented regarding patient-specific geometries, where the aortic valves are defined by analytical orifices. Results show that, while the patient without pathology displays a typical hemodynamic behavior of flows in bends, BAV-related aortas present an accelerated flow along the outer aortic wall. Wall shear stress (WSS) overload in the outer curvature is observed, more marked in more dilated aortas. Moreover, helices in the ascending aorta are present in these patients, enhanced with greater dilation. These findings support the fact that hemodynamic factors play an important role in aortic dilation onset and development in BAV patients, caused by a prolonged exposure of the outer ascending aortic curvature to altered WSS. Besides, our results suggest that greater aortic regurgitation may be associated with abnormal WSS distributions in the ascending aorta during diastole, which can facilitate aortic root dilation.
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Affiliation(s)
- DIANA C. OLIVEIRA
- Department of Bioengineering and CEMAT, Instituto Superior Técnico, Ulisboa Av. Rovisco Pais, 1 1049-001 Lisboa, Portugal
| | - SÉRGIO LARANJO
- Pediatric Cardiology Department, Congenital Heart Diseases Reference Centre, Hospital de Santa Marta (CHLC), Rua de Santa Marta 50 1169-024 Lisboa, Portugal
| | - JORGE TIAGO
- Department of Mathematics and CEMAT, Instituto Superior Técnico, Ulisboa Av. Rovisco Pais, 1 1049-001 Lisboa, Portugal
| | - FÁTIMA F. PINTO
- Pediatric Cardiology Department, Congenital Heart Diseases Reference Centre, Hospital de Santa Marta (CHLC), Rua de Santa Marta 50 1169-024 Lisboa, Portugal
| | - ADÉLIA SEQUEIRA
- Department of Mathematics and CEMAT, Instituto Superior Técnico, Ulisboa Av. Rovisco Pais, 1 1049-001 Lisboa, Portugal
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