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Deus J, Martin E. Efficient Cardiovascular Parameters Estimation for Fluid-Structure Simulations Using Gappy Proper Orthogonal Decomposition. Ann Biomed Eng 2024:10.1007/s10439-024-03568-z. [PMID: 38969956 DOI: 10.1007/s10439-024-03568-z] [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: 12/22/2023] [Accepted: 06/21/2024] [Indexed: 07/07/2024]
Abstract
As full-scale detailed hemodynamic simulations of the entire vasculature are not feasible, numerical analysis should be focused on specific regions of the cardiovascular system, which requires the identification of lumped parameters to represent the patient behavior outside the simulated computational domain. We present a novel technique for estimating cardiovascular model parameters using gappy Proper Orthogonal Decomposition (g-POD). A POD basis is constructed with FSI simulations for different values of the lumped model parameters, and a linear operator is applied to retain information that can be compared to the available patient measurements. Then, the POD coefficients of the reconstructed solution are computed either by projecting patient measurements or by solving a minimization problem with constraints. The POD reconstruction is then used to estimate the model parameters. In the first test case, the parameter values of a 3-element Windkessel model are approximated using artificial patient measurements, obtaining a relative error of less than 4.2%. In the second case, 4 sets of 3-element Windkessel are approximated in a patient's aorta geometry, resulting in an error of less than 8% for the flow and less than 5% for the pressure. The method shows accurate results even with noisy patient data. It automatically calculates the delay between measurements and simulations and has flexibility in the types of patient measurements that can handle (at specific points, spatial or time averaged). The method is easy to implement and can be used in simulations performed in general-purpose FSI software.
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Affiliation(s)
- J Deus
- Departamento de Ingeniería Mecánica, Máquinas y Motores Térmicos y Fluidos, Universidade de Vigo, Campus Marcosende, 36310, Vigo, Spain
| | - E Martin
- Departamento de Ingeniería Mecánica, Máquinas y Motores Térmicos y Fluidos, Universidade de Vigo, Campus Marcosende, 36310, Vigo, Spain.
- Instituto de Física y Ciencias Aeroespaciales (IFCAE), Universidade de Vigo, Campus de As Lagoas, 32004, Ourense, Spain.
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Hoganson DM, Govindarajan V, Schulz NE, Eickhoff ER, Breitbart RE, Marx GR, del Nido PJ, Hammer PE. Multiphysiologic State Computational Fluid Dynamics Modeling for Planning Fontan With Interrupted Inferior Vena Cava. JACC. ADVANCES 2024; 3:101057. [PMID: 39129987 PMCID: PMC11312337 DOI: 10.1016/j.jacadv.2024.101057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 03/01/2024] [Accepted: 04/21/2024] [Indexed: 08/13/2024]
Abstract
Background Single ventricle (SV) patients with interrupted inferior vena cava (iIVC) and azygos continuation are at high risk for unbalanced hepatic venous flow (HVF) distribution to the lungs after Fontan completion and subsequent pulmonary arteriovenous malformations (AVMs) formation. Objectives The aim of the study was to utilize computational fluid dynamics (CFD) analysis to avoid maldistribution of HVF to the lungs after Fontan surgery. Methods Four SV subjects with iIVC were prospectively studied with a 3-dimensional (3D) modeling workflow with digital 3D models created from segmented magnetic resonance images or computer tomography scans, virtual surgery, and CFD analysis over multiple physiologic states for the evaluation of operative plans to achieve balanced HVF to both lungs. Three of the patients were Fontan revision candidates with existing AVMs. All patients underwent Fontan completion or revision surgery. Results CFD predicted that existing or proposed Fontan completion in all patients would result in 100% of HVF to one lung. Improved HVF balance was achieved with CFD analysis of alternative surgical approaches resulting in the average distribution of HVF to the right/left pulmonary arteries of 37%/63% ± 10.4%. A hepatoazygos shunt was required in all patients and additional creation of an innominate vein in one. CFD analysis was validated by the comparison of pre-operative predicted and postoperative MRI-measured total right/left pulmonary flow (51%/49% ± 5.4% vs 49%/51% ± 8.5%). Conclusions A 3D modeling workflow with CFD simulation for SV patients with iIVC may avoid HVF maldistribution and development of AVMs after Fontan completion.
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Affiliation(s)
- David M. Hoganson
- Department of Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Vijay Govindarajan
- Department of Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Noah E. Schulz
- Department of Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Emily R. Eickhoff
- Department of Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Roger E. Breitbart
- Department of Cardiology, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Gerald R. Marx
- Department of Cardiology, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Pedro J. del Nido
- Department of Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Peter E. Hammer
- Department of Cardiac Surgery, Boston Children’s Hospital, Boston, Massachusetts, USA
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Aramburu J, Ruijsink B, Chabiniok R, Pushparajah K, Alastruey J. Patient-specific closed-loop model of the fontan circulation: Calibration and validation. Heliyon 2024; 10:e30404. [PMID: 38742066 PMCID: PMC11089314 DOI: 10.1016/j.heliyon.2024.e30404] [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: 01/08/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/16/2024] Open
Abstract
The Fontan circulation, designed for managing patients with a single functional ventricle, presents challenges in long-term outcomes. Computational methods offer potential solutions, yet their application in cardiology practice remains largely unexplored. Our aim was to assess the ability of a patient-specific, closed-loop, reduced-order blood flow model to simulate pulsatile blood flow in the Fontan circulation. Using one-dimensional models, we simulated the aorta, superior and inferior venae cavae, and right and left pulmonary arteries, while lumping heart chambers and remaining vessels into zero-dimensional models. The model was calibrated with patient-specific haemodynamic data from combined cardiac catheterisation and magnetic resonance exams, using a novel physics-based stepwise methodology involving simpler open-loop models. Testing on a 10-year-old, anesthetised patient, demonstrated the model's capability to replicate pulsatile pressure and flow in the larger vessels and ventricular pressure. Average relative errors in mean pressure and flow were 2.9 % and 3.6 %, with average relative point-to-point errors (RPPE) in pressure and flow at 5.2 % and 16.0 %. Comparing simulation results to measurements, mean aortic pressure and flow values were 50.7 vs. 50.4 mmHg and 41.6 vs. 41.9 ml/s, respectively, while ventricular pressure values were 28.7 vs. 27.4 mmHg. The model accurately described time-varying ventricular volume with a RPPE of 2.9 %, with mean, minimum, and maximum ventricular volume values for simulation results vs. measurements at 59.2 vs. 58.2 ml, 38.0 vs. 37.6 ml, and 76.0 vs. 74.4 ml, respectively. It provided physiologically realistic predictions of haemodynamic changes from pulmonary vasodilation and atrial fenestration opening. The new model and calibration methodology are freely available, offering a platform to virtually investigate the Fontan circulation's response to clinical interventions and explore potential mechanisms of Fontan failure. Future efforts will concentrate on broadening the model's applicability to a wider range of patient populations and clinical scenarios, as well as testing its effectiveness.
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Affiliation(s)
- Jorge Aramburu
- Universidad de Navarra, TECNUN Escuela de Ingeniería, P° Manuel Lardizabal 13, 20018, Donostia/San Sebastián, Spain
| | - Bram Ruijsink
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, SE1 7EH, London, UK
| | - Radomir Chabiniok
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, SE1 7EH, London, UK
- Division of Pediatric Cardiology, Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kuberan Pushparajah
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, SE1 7EH, London, UK
- Department of Congenital Heart Disease, Evelina Children's Hospital, SE1 7EH, London, UK
| | - Jordi Alastruey
- School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, SE1 7EH, London, UK
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Govindarajan V, Marshall L, Sahni A, Cetatoiu MA, Eickhoff EE, Davee J, St Clair N, Schulz NE, Hoganson DM, Hammer PE, Ghelani SJ, Prakash A, Del Nido PJ, Rathod RH. Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation. Circ Cardiovasc Imaging 2024; 17:e016104. [PMID: 38567518 PMCID: PMC11073583 DOI: 10.1161/circimaging.123.016104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling. METHODS SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. RESULTS SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased. CONCLUSIONS Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.
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Affiliation(s)
- Vijay Govindarajan
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Surgery (V.G., D.M.H., P.E.H.), Harvard Medical School, Boston, MA
- Department of Internal Medicine, University of Texas Health Science Center at Houston (V.G.)
| | - Lauren Marshall
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Akshita Sahni
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Maria A Cetatoiu
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Emily E Eickhoff
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Jocelyn Davee
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Nicole St Clair
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - Noah E Schulz
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
| | - David M Hoganson
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Surgery (V.G., D.M.H., P.E.H.), Harvard Medical School, Boston, MA
| | - Peter E Hammer
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Surgery (V.G., D.M.H., P.E.H.), Harvard Medical School, Boston, MA
| | - Sunil J Ghelani
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
| | - Ashwin Prakash
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
| | - Pedro J Del Nido
- Departments of Cardiovascular Surgery (V.G., L.M., A.S., M.A.C., E.E.E., J.D., N.S.C., N.E.S., D.M.H., P.E.H., S.J.G., A.P., P.J.d.N.), Boston Children's Hospital, MA
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
| | - Rahul H Rathod
- Cardiology (S.J.G., A.P., P.J.d.N., R.H.R.), Boston Children's Hospital, MA
- Departments of Pediatrics (R.H.R.), Harvard Medical School, Boston, MA
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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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Govindarajan V, Marshall L, Sahni A, Cetatoiu M, Eickhoff E, Davee J, St Clair N, Schulz N, Hoganson DM, Hammer PE, Ghelani S, Prakash A, Del Nido PJ, Rathod RH. Impact of Age-related change in Caval Flow Ratio on Hepatic Flow Distribution in Fontan. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.06.23295166. [PMID: 37732201 PMCID: PMC10508792 DOI: 10.1101/2023.09.06.23295166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Background The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac (EC) conduit or a lateral tunnel (LT) connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. Objective The effect of age-related changes in caval inflows on HFD was evaluated using cardiac MRI (CMR) data and patient-specific computational fluid dynamics (CFD) modeling. Methods SVC and IVC flow from 414 Fontan patients were collected to establish a relationship between SVC:IVC flow ratio and age. CFD modeling was performed in 60 (30 EC and 30 LT) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. Results SVC:IVC flow ratio inverted at ∼8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC = 2,1, and 0.5 corresponded to ages 3, 8, and 15+ respectively) was not significant for EC but statistically significant for LT cohorts. For all three caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2→0.5 (age 3→15+), the correlation's strength decreased from 0.87→0.64, due to potential flow perturbation as IVC flow momentum increased. Conclusion Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of including SVC:IVC variations over time to understand Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes. Clinical Perspective With improvement in standard of care and management of single ventricle patients with Fontan physiology, the population of adults with Fontan circulation is increasing. Consequently, there is a clinical need to comprehend the impact of patient growth on Fontan hemodynamics. Using CMR data, we were able to quantify the relationship between changing caval inflows and somatic growth. We then used patient-specific computational flow modeling to quantify how this relationship affected the distribution of long-term hepatic flow in extracardiac and lateral tunnel Fontan types. Our findings demonstrated the significance of including SVC:IVC changes over time in CFD modeling to learn more about the long-term hemodynamics of Fontan. Fontan surgical approaches are increasingly planned and optimized using computational flow modeling. For a patient undergoing a Fontan procedure, the workflow presented in this study that takes into account the variations in Caval inflows over time can aid in predicting the long-term hemodynamics in a planned Fontan pathway.
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Assi IZ, Lynch SR, Samulak K, Williams DM, Wakefield TW, Obi AT, Figueroa CA. An ultrasound imaging and computational fluid dynamics protocol to assess hemodynamics in iliac vein compression syndrome. J Vasc Surg Venous Lymphat Disord 2023; 11:1023-1033.e5. [PMID: 37353157 DOI: 10.1016/j.jvsv.2023.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 05/10/2023] [Accepted: 05/17/2023] [Indexed: 06/25/2023]
Abstract
OBJECTIVE Elevated shear rates are known to play a role in arterial thrombosis; however, shear rates have not been thoroughly investigated in patients with iliac vein compression syndrome (IVCS) owing to imaging limitations and assumptions on the low shear nature of venous flows. This study was undertaken to develop a standardized protocol that quantifies IVCS shear rates and can aid in the diagnosis and treatment of patients with moderate yet symptomatic compression. METHODS Study patients with and without IVCS had their iliac vein hemodynamics measured via duplex ultrasound (US) at two of the following three vessel locations: infrarenal inferior vena cava (IVC), right common iliac vein, and left common iliac vein, in addition to acquiring data at the right and left external iliac veins. US velocity spectra were multiplied by a weighted cross-sectional area calculated from US and computed tomography (CT) data to create flow waveforms. Flow waveforms were then scaled to enforce conservation of flow across the IVC and common iliac veins. A three-dimensional (3D), patient-specific model of the iliac vein anatomy was constructed from CT and US examination. Flow waveforms and the 3D model were used as a basis to run a computational fluid dynamics (CFD) simulation. Owing to collateral vessel flow and discrepancies between CT and US area measurements, flows in internal iliac veins and cross-sectional areas of the common iliac veins were calibrated iteratively against target common iliac flow. Simulation results on mean velocity were validated against US data at measurement locations. Simulation results were postprocessed to derive spatial and temporal values of quantities such as velocity and shear rate. RESULTS Using our modeling protocol, we were able to build CFD models of the iliac veins that matched common iliac flow splits within 2% and measured US velocities within 10%. Proof-of-concept analyses (1 subject, 1 control) have revealed that patients with IVCS may experience elevated shear rates in the compressed left common iliac vein, more typical of the arterial rather than the venous circulation. These results encourage us to extend this protocol to a larger group of patients with IVCS and controls. CONCLUSIONS We developed a protocol that obtains hemodynamic measurements of the IVC and iliac veins from US, creates patient-specific 3D reconstructions of the venous anatomy using CT and US examinations, and computes shear rates using calibrated CFD methods. Proof-of-concept results have indicated that patients with IVCS may experience elevated shear rates in the compressed left common iliac vein. Larger cohorts are needed to assess the relationship between venous compression and shear rates in patients with IVCS as compared with controls with noncompressed iliac veins. Further studies using this protocol may also give promising insights into whether or not to treat patients with moderate, yet symptomatic compression.
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Affiliation(s)
- Ismael Z Assi
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - Sabrina R Lynch
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - Krystal Samulak
- Section of Vascular Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI
| | - David M Williams
- Division of Interventional Radiology, Department of Radiology, University of Michigan Health System, Ann Arbor, MI
| | - Thomas W Wakefield
- Section of Vascular Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI
| | - Andrea T Obi
- Section of Vascular Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI; Section of Vascular Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor, MI.
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Kwan KJS, Li HL, Chan YC, Cheng SWK. Safety and Efficacy of Inner Branched Stent-Graft in the Treatment of Aortic Arch Disease: A Systematic Review. J Endovasc Ther 2023:15266028231197395. [PMID: 37646117 DOI: 10.1177/15266028231197395] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
OBJECTIVE To provide a descriptive overview on the contemporary outcomes of thoracic endovascular arch repair with inner branched endoprosthesis (bTEVAR) for the treatment of aortic arch pathologies. METHODS A comprehensive literature search was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Pre-defined search terms were used to interrogate PubMed and OVID Medline databases from January 1999 to July 2022. Patient characteristics, indication for treatment, procedural data, mortality rates, postoperative complications, and reintervention rate during follow-up were evaluated. RESULTS Nineteen articles were included, encompassing a total of 618 patients who received bTEVAR, most of which were double-branched (63.9%, n=395). The main indication for treatment was aneurysm secondary to chronic aortic dissection (38.8%, n=240/618) with a mean maximum diameter of 58.3±11.4 mm. Pooled mean technical success rate was 97.4±4.4% (95% confidence interval [CI]=95.1%-99.5%); 2 and 3 patients required conversion to chimney technique and open repair, respectively. Among the pooled rates of early complications, postoperative stroke was the highest (10.5%; 95% CI=6.8%-14.3%). Thirty-day and in-hospital mortality rate was 5.5% (95% CI=2.6%-9.7%). Forty patients (6.5%; 95% CI=2.5%-9.5%) required early reintervention. During a mean follow-up of 20.7±13.5 months, the mortality rate was 18.2% (n=108/593; 95% CI=8.6%-20.6%) where 12 (11.1%) were aortic-related. Pooled late reintervention rate was 9.6% (95% CI=4.8%-14.3%). Comparison of demographics and outcomes found no significant difference between single and double bTEVAR. CONCLUSION Branched thoracic endovascular aortic repair is a promising approach for aortic arch pathologies with a high technical success rate despite a steep learning curve. However, contemporary outcomes reflect that postoperative stroke remains the predominant concern. Further experience and long-term follow-up are required to sufficiently elucidate the safety and durability of bTEVAR in the management of aortic pathologies for high-risk patients. CLINICAL IMPACT This systematic review summarized the contemporary outcomes of thoracic endovascular aortic repair with different inner branched stent-grafts for the management of aortic arch pathologies. Pooled results from nineteen studies with 618 patients demonstrated a high technical success rate and an acceptable mortality rate. However, postoperative stroke remains the major concern. Long-term follow-up is needed to evaluate its durability.
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Affiliation(s)
- Kristine J S Kwan
- International School, Jinan University, Guangzhou, China
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Hai-Lei Li
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Yiu Che Chan
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
- Division of Vascular & Endovascular Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong, China
| | - Stephen W K Cheng
- Division of Vascular Surgery, Department of Surgery, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
- Division of Vascular & Endovascular Surgery, Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong, China
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9
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Zhao Y, Wang H, Chen W, Sun W, Yu X, Sun C, Hua G. Time-resolved simulation of blood flow through left anterior descending coronary artery: effect of varying extent of stenosis on hemodynamics. BMC Cardiovasc Disord 2023; 23:156. [PMID: 36973644 PMCID: PMC10041719 DOI: 10.1186/s12872-023-03190-2] [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: 01/03/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Real-time blood flow variation is crucial for understanding the dynamic development of coronary atherosclerosis. The main objective of this study is to investigate the effect of varying extent of stenosis on the hemodynamic features in left anterior descending coronary artery. METHODS Various Computational fluid dynamics (CFD) models were constructed with patient-specific CT image data, using actual fractional flow reserve (FFR) as boundary conditions to provide a real-time quantitative description of hemodynamic properties. The hemodynamic parameters, such as the local and instantaneous wall shear stress (WSS), oscillating shear index (OSI) and relative residence time (RRT), blood flow velocity and pressure drop during various phases of cardiac cycle were provided in detail. RESULTS There was no evident variation in hemodynamic parameters in the cases of less than 50% stenosis while there were abrupt and dramatic changes in hemodynamics when the stenosis aggravated from 60 to 70%. Furthermore, when the stenosis was beyond 70%, there existed substantial pressure difference, WSS, and blood flow velocity in the center of the stenosis. Although OSI and RRT increased along with the aggravation of stenosis, they appeared with obvious abnormalities across all cases, even in mild stenosis. CONCLUSION The simulation could present a dynamic and comprehensive profile of how hemodynamic parameters vary in accordance with divergent severities of stenosis, which could serve as an effective reference for the clinicians to have a deeper insight into the pathological mechanism of coronary atherosclerosis and stenosis.
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Affiliation(s)
- Yinghong Zhao
- China University of Mining and Technology, No.1, Daxue Road, Xuzhou, Jiangsu, China.
- Xuzhou Medical University, 209 Tongshan Road, Xuzhou, Jiangsu, China.
| | - Huihui Wang
- Xuzhou Medical University, 209 Tongshan Road, Xuzhou, Jiangsu, China
| | | | - Wenyue Sun
- Xuzhou Medical University, 209 Tongshan Road, Xuzhou, Jiangsu, China
| | - Xianchao Yu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Cunjie Sun
- The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Gang Hua
- China University of Mining and Technology, No.1, Daxue Road, Xuzhou, Jiangsu, China.
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10
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García-Galindo A, Agujetas R, López-Mínguez JR, Ferrera C. Assessment of valve implantation in the descending aorta as an alternative for aortic regurgitation patients not treatable with conventional procedures. Biomech Model Mechanobiol 2022; 22:575-591. [PMID: 36550245 PMCID: PMC10097802 DOI: 10.1007/s10237-022-01665-3] [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: 09/15/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Aortic Regurgitation (AR) produces the entrance of an abnormal amount of blood in the left ventricle. This disease is responsible for high morbidity and mortality worldwide and may be caused by an aortic valve dysfunction. Surgical and transcatheter aortic valve replacement (TAVR) are the current options for treating AR. They have replaced older procedures such as Hufnagel's one. However, some physicians have reconsidered this procedure as a less aggressive alternative for patients not eligible for surgical or TAVR. Although Hufnagel suggested a 75% regurgitation reduction when a valve is placed in the descending aorta, a quantification of this value has not been reported. METHODS In this paper, CFD/FSI numerical simulation is conducted on an idealized geometry. We quantify the effect of placing a bileaflet mechanical heart valve in the descending aorta on a moderate-severe AR case. A three-element Windkessel model is employed to prescribe pressure outlet boundary conditions. We calculate the resulting flow rates and pressures at the aorta and first-generation vessels. Moreover, we evaluate several indices to assess the improvement due to the valve introduction. RESULTS AND CONCLUSIONS Regurgitation fraction (RF) is reduced from 37.5% (without valve) to 18.0% (with valve) in a single cardiac cycle. This reduction clearly shows the remarkable efficacy of the rescued technique. It will further ameliorate the left ventricle function in the long-term. Moreover, the calculations show that the implantation in that location introduces fewer incompatibilities' risks than a conventional one. The proposed methodology can be extended to any particular conditions (pressure waveforms/geometry) and is designed to assess usual clinical parameters employed by physicians.
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Affiliation(s)
- A García-Galindo
- Departamento de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006, Badajoz, Spain
| | - R Agujetas
- Departamento de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006, Badajoz, Spain
| | - J R López-Mínguez
- Sección de Cardiologıa Intervencionista, Servicio de Cardiologıa, Hospital Universitario de Badajoz, Avda. de Elvas s/n, E-06006, Badajoz, Spain
| | - C Ferrera
- Departamento de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, E-06006, Badajoz, Spain.
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11
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Jin J, Ma X, Fu X, Zhang Z, Yu J. Fluid-Structure Interaction Model for Predicting Surgical Result of Total Anomalous Pulmonary Venous Connection and Estimating Pulmonary Venous Properties. Cardiovasc Eng Technol 2022; 13:725-734. [PMID: 35233750 DOI: 10.1007/s13239-022-00613-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 02/02/2022] [Indexed: 01/27/2023]
Abstract
OBJECTIVES To build a fluid-structure interaction model of pulmonary veins with total anomalous pulmonary venous connection, which can be used to predict the result of surgical treatment and at the same time to estimate the elastic properties of pulmonary veins based on patient-specific data and clinic postoperative results. METHODS The fluid-structure interaction (FSI) model was used to simulate the anastomosis on pulmonary veins based on computed tomography angiography data collected from three children with total anomalous pulmonary venous connection (TAPVC), supra-cardiac type. The deformation and the stress of anastomosis, and also the velocity of blood flow were calculated in fluid-structure coupling algorithm. During the simulation the variable boundary conditions were applied, including the thickness of vessel wall and the vessel elasticity for which was selected a range of values. The calculation results were finally compared to postoperative results of same patients and discussed. The corresponding outcomes are given in the conclusions section. RESULTS The blood flow velocity through the outlet will vary depending on the properties of vessels, including physical properties and thickness of vessel wall. The stress on vessel is lower for smaller values of Young's modulus. The calculated blood flow velocity correlates well with the postoperative results for the Young's modulus of vessels ranging from 0.5 to 1.0 MPa. CONCLUSIONS The FSI model has high potential to predict the result of surgery for TAPVC and to estimate the physical properties of pulmonary vein. This model also has potential to guide the strategy for surgical treatment.
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Affiliation(s)
- Jie Jin
- Department of Cardiac Surgery, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, People's Republic of China.
| | - Xiaohui Ma
- Department of Radiology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, People's Republic of China
| | - Xingpeng Fu
- Department of Ultrasonography, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, People's Republic of China
| | - Zewei Zhang
- Department of Cardiac Surgery, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, People's Republic of China
| | - Jiangen Yu
- Department of Cardiac Surgery, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, People's Republic of China
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12
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Schafstedde M, Yevtushenko P, Nordmeyer S, Kramer P, Schleiger A, Solowjowa N, Berger F, Photiadis J, Mykychak Y, Cho MY, Ovroutski S, Kuehne T, Brüning J. Virtual treatment planning in three patients with univentricular physiology using computational fluid dynamics—Pitfalls and strategies. Front Cardiovasc Med 2022; 9:898701. [PMID: 35990961 PMCID: PMC9381838 DOI: 10.3389/fcvm.2022.898701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundUneven hepatic venous blood flow distribution (HFD) to the pulmonary arteries is hypothesized to be responsible for the development of intrapulmonary arteriovenous malformations (PAVM) in patients with univentricular physiology. Thus, achieving uniform distribution of hepatic blood flow is considered favorable. However, no established method for the prediction of the post-interventional hemodynamics currently exists. Computational fluid dynamics (CFD) offers the possibility to quantify HFD in patient-specific anatomies before and after virtual treatment. In this study, we evaluated the potential benefit of CFD-assisted treatment planning.Materials and methodsThree patients with total cavopulmonary connection (TCPC) and PAVM underwent cardiovascular magnetic resonance imaging (CMR) and computed tomography imaging (CT). Based on this imaging data, the patient-specific anatomy was reconstructed. These patients were considered for surgery or catheter-based intervention aiming at hepatic blood flow re-routing. CFD simulations were then performed for the untreated state as well as for different surgical and interventional treatment options. These treatment options were applied as suggested by treating cardiologists and congenital heart surgeons with longstanding experience in interventional and surgical treatment of patients with univentricular physiology. HFD was quantified for all simulations to identify the most viable treatment decision regarding redistribution of hepatic blood flow.ResultsFor all three patients, the complex TCPC anatomy could be reconstructed. However, due to the presence of metallic stent implants, hybrid models generated from CT as well as CMR data were required. Numerical simulation of pre-interventional HFD agreed well with angiographic assessment and physiologic considerations. One treatment option resulting in improvement of HFD was identified for each patient. In one patient follow-up data after treatment was available. Here, the virtual treatment simulation and the CMR flow measurements differed by 15%.ConclusionThe combination of modern computational methods as well as imaging methods for assessment of patient-specific anatomy and flow might allow to optimize patient-specific therapy planning in patients with pronounced hepatic flow mismatch and PAVM. In this study, we demonstrate that these methods can also be applied in patients with complex univentricular physiology and extensive prior interventions. However, in those cases, hybrid approaches utilizing information of different image modalities may be required.
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Affiliation(s)
- Marie Schafstedde
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
- Institute for Cardiovascular Computer-Assisted Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
- German Centre for Cardiovascular Research, Partner Site Berlin, Berlin, Germany
- *Correspondence: Marie Schafstedde,
| | - Pavlo Yevtushenko
- Institute for Cardiovascular Computer-Assisted Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Sarah Nordmeyer
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
- Institute for Cardiovascular Computer-Assisted Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Kramer
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
| | - Anastasia Schleiger
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
| | - Natalia Solowjowa
- Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany
| | - Felix Berger
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
- German Centre for Cardiovascular Research, Partner Site Berlin, Berlin, Germany
- Department of Pediatric Cardiology, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Joachim Photiadis
- Department of Congenital Heart Surgery, German Heart Center Berlin, Berlin, Germany
| | - Yaroslav Mykychak
- Department of Congenital Heart Surgery, German Heart Center Berlin, Berlin, Germany
| | - Mi-Young Cho
- Department of Congenital Heart Surgery, German Heart Center Berlin, Berlin, Germany
| | - Stanislav Ovroutski
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
| | - Titus Kuehne
- Department of Congenital Heart Disease–Pediatric Cardiology, German Heart Center Berlin, Berlin, Germany
- Institute for Cardiovascular Computer-Assisted Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
- German Centre for Cardiovascular Research, Partner Site Berlin, Berlin, Germany
| | - Jan Brüning
- Institute for Cardiovascular Computer-Assisted Medicine, Charité–Universitätsmedizin Berlin, Berlin, Germany
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13
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Khinsoe G, Bappoo N, Kelsey LJ, Blom D, Doyle BJ, Jansen S. Computational biomechanics: a potential new tool for the vascular surgeon in personalized management. ANZ J Surg 2022; 92:1308-1311. [PMID: 35688636 DOI: 10.1111/ans.17476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 11/16/2021] [Accepted: 12/21/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Georgia Khinsoe
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Nikhilesh Bappoo
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Dirk Blom
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,Curtin Medical School, Curtin University, Perth, Western Australia, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands and the UWA Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia.,School of Engineering, The University of Western Australia, Perth, Western Australia, Australia.,Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK.,Australian Research Council Centre for Personalised Therapeutics Technologies, Australia
| | - Shirley Jansen
- Curtin Medical School, Curtin University, Perth, Western Australia, Australia.,Heart and Vascular Research Institute, Harry Perkins Institute of Medical Research, QEII Medical Centre, Perth, Western Australia, Australia.,Department of Vascular and Endovascular Surgery, Sir Charles Gardiner Hospital, Perth, Western Australia, Australia.,Medical School, The University of Western Australia, Perth, Western Australia, Australia
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14
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Stevens RM, Sun J, Throckmorton A, Garven E, Poletto E. Invited commentary for: Essential role of cardiac computed tomography for surgical decision making in children with total anomalous pulmonary venous connection and single ventricle. J Card Surg 2022; 37:2166-2167. [PMID: 35485638 DOI: 10.1111/jocs.16497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 11/30/2022]
Abstract
Thousands of neonates are born each year with complex congenital heart defects, such as total anomalous pulmonary venous connection combined with single ventricle physiology. This dual diagnosis with significant vessel and ventricular complexity requires alternative additional imaging to fully visualize the anatomical challenge and devise the appropriate treatment strategy for the patient.
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Affiliation(s)
- Randy M Stevens
- Department of Pediatric Cardiac Surgery, St. Christopher's Hospital for Children, Drexel University College of Medicine, Merion Station, Pennsylvania, USA
| | - Jie Sun
- Department of Pediatric Cardiology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Merion Station, Pennsylvania, USA
| | - Amy Throckmorton
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Merion Station, Pennsylvania, USA
| | - Ellen Garven
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Merion Station, Pennsylvania, USA
| | - Erica Poletto
- Department of Pediatric Radiology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Merion Station, Pennsylvania, USA
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15
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Tobin N, Good BC, Plasencia JD, Fogel MA, Weiss WJ, Manning KB. Computational Investigation of Anastomosis Options of a Right-Heart Pump to Patient Specific Pulmonary Arteries. Ann Biomed Eng 2022; 50:929-940. [PMID: 35451680 DOI: 10.1007/s10439-022-02969-2] [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: 06/15/2021] [Accepted: 04/12/2022] [Indexed: 11/30/2022]
Abstract
Patients with Fontan circulation have increased risk of heart failure, but are not always candidates for heart transplant, leading to the development of the subpulmonic Penn State Fontan Circulation Assist Device. The aim of this study was to use patient-specific computational fluid dynamics simulations to evaluate anastomosis options for implanting this device. Simulations were performed of the pre-surgical anatomy as well as four surgical options: a T-junction and three Y-grafts. Cases were evaluated based on several fluid-dynamic quantities. The impact of imbalanced left-right pulmonary flow distribution was also investigated. Results showed that a 12-mm Y-graft was the most energy efficient. However, an 8-mm graft showed more favorable wall shear stress distribution, indicating lower risk of thrombosis and endothelial damage. The 8-mm Y-grafts also showed a more balanced pulmonary flow split, and lower residence time, also indicating lower thrombosis risk. The relative performance of the surgical options was largely unchanged whether or not the pulmonary vascular resistance remained imbalanced post-implantation.
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Affiliation(s)
- Nicolas Tobin
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Bryan C Good
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | | | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - William J Weiss
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, 17033, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA. .,Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, 17033, USA.
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16
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Bracamonte JH, Saunders SK, Wilson JS, Truong UT, Soares JS. Patient-Specific Inverse Modeling of In Vivo Cardiovascular Mechanics with Medical Image-Derived Kinematics as Input Data: Concepts, Methods, and Applications. APPLIED SCIENCES-BASEL 2022; 12:3954. [PMID: 36911244 PMCID: PMC10004130 DOI: 10.3390/app12083954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inverse modeling approaches in cardiovascular medicine are a collection of methodologies that can provide non-invasive patient-specific estimations of tissue properties, mechanical loads, and other mechanics-based risk factors using medical imaging as inputs. Its incorporation into clinical practice has the potential to improve diagnosis and treatment planning with low associated risks and costs. These methods have become available for medical applications mainly due to the continuing development of image-based kinematic techniques, the maturity of the associated theories describing cardiovascular function, and recent progress in computer science, modeling, and simulation engineering. Inverse method applications are multidisciplinary, requiring tailored solutions to the available clinical data, pathology of interest, and available computational resources. Herein, we review biomechanical modeling and simulation principles, methods of solving inverse problems, and techniques for image-based kinematic analysis. In the final section, the major advances in inverse modeling of human cardiovascular mechanics since its early development in the early 2000s are reviewed with emphasis on method-specific descriptions, results, and conclusions. We draw selected studies on healthy and diseased hearts, aortas, and pulmonary arteries achieved through the incorporation of tissue mechanics, hemodynamics, and fluid-structure interaction methods paired with patient-specific data acquired with medical imaging in inverse modeling approaches.
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Affiliation(s)
- Johane H. Bracamonte
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Sarah K. Saunders
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - John S. Wilson
- Department of Biomedical Engineering and Pauley Heart Center, Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Uyen T. Truong
- Department of Pediatrics, School of Medicine, Children’s Hospital of Richmond at Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Joao S. Soares
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
- Correspondence:
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17
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In Vitro Measurement of Hepatic Flow Distribution in Fontan Vascular Conduits: Towards Rapid Validation Techniques. J Biomech 2022; 137:111092. [DOI: 10.1016/j.jbiomech.2022.111092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 04/08/2022] [Accepted: 04/08/2022] [Indexed: 11/24/2022]
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18
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Computational Study of Abdominal Aortic Aneurysms with Severely Angulated Neck Based on Transient Hemodynamics Using an Idealized Model. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12042113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
An abdominal aortic aneurysm (AAA) is an enlargement of the abdominal aorta that can become a life-threatening disease. The pulsatile blood flow exhibits intricate laminar patterns in the abdominal portion of the human aorta under normal resting conditions, whereas secondary flows are caused by adjacent branches and abnormal vessel geometries. If a pathological disorder (e.g., aneurysm) alters the structural composition of the artery wall, the flow dynamics become more complex. In this study, we analyzed the hemodynamics of pulsatile blood flow in three-dimensional AAA models. Computational predictions of hemodynamic changes were performed considering idealized models for four severe proximal neck angulations of symmetric aneurysms assuming conditions of laminar flow and a rigid artery wall. The predictions were based on computational fluid dynamics throughout the cardiac cycle. Postprocessing was used to visualize the numerical findings. The hemodynamic changes in factors such as velocity, flow streamline, pressure, and wall shear stress were obtained and visualized. The resulting blood flow through the severely angulated proximal neck of the abdominal aorta caused strong turbulence and asymmetric flow inside the aneurysm sac, leading to blood recirculation, especially during diastole. The simulation results showed the formation of regions with high and low wall shear stress, turbulent flow, and recirculation in the aneurysm sac depending on the angulation, which could have led to aortic wall weakness.
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19
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Rigatelli G, Chiastra C, Pennati G, Dubini G, Migliavacca F, Zuin M. Applications of computational fluid dynamics to congenital heart diseases: a practical review for cardiovascular professionals. Expert Rev Cardiovasc Ther 2021; 19:907-916. [PMID: 34704881 DOI: 10.1080/14779072.2021.1999229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The increased survival rate of patients with congenital heart disease (CHD) has made it likely that 70%-95% of infants with CHDs surviving into adulthood often require careful follow-up and (repeat) interventions. Patients with CHDs often have abnormal blood flow patterns, due to both primary cardiac defect and the consequent surgical or endovascular repair. AREA COVERED Computational fluid dynamics (CFD) alone or coupled with advanced imaging tools can assess blood flow patterns of CHDs to both understand their pathophysiology and anticipate the results of surgical or interventional repair. EXPERT OPINION CFD is a mathematical technique that quantifies and describes the characteristics of fluid flow using the laws of physics. Through dedicated software based on virtual reconstruction and simulation and patients' real data coming from computed tomography, magnetic resonance imaging, and 3/4 D-ultrasound, reconstruction of models of circulation of most CHD can be accomplished. CFD can provide insights about the pathophysiology of coronary artery anomalies, interatrial shunts, coarctation of the aorta and aortic bicuspid valve, tetralogy of Fallot and univentricular heart, with the capability in some cases of simulating different types of surgical or interventional repair and tailoring the treatment on the basis of these findings.
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Affiliation(s)
- Gianluca Rigatelli
- Cardiovascular Diagnosis and Endoluminal Interventions Unit, Rovigo General Hospital, Rovigo, Italy
| | - Claudio Chiastra
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Giancarlo Pennati
- Laboratory of Biological Structure Mechanics (Labs), Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Milan, Italy
| | - Gabriele Dubini
- Laboratory of Biological Structure Mechanics (Labs), Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Milan, Italy
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics (Labs), Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Milan, Italy
| | - Marco Zuin
- Section of Internal and Cardiopulmonary Medicine, University of Ferrara, Ferrara, Italy
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Ahmed Y, Tossas-Betancourt C, van Bakel PAJ, Primeaux JM, Weadock WJ, Lu JC, Zampi JD, Salavitabar A, Figueroa CA. Interventional Planning for Endovascular Revision of a Lateral Tunnel Fontan: A Patient-Specific Computational Analysis. Front Physiol 2021; 12:718254. [PMID: 34489735 PMCID: PMC8418142 DOI: 10.3389/fphys.2021.718254] [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: 05/31/2021] [Accepted: 07/12/2021] [Indexed: 11/21/2022] Open
Abstract
Introduction A 2-year-old female with hypoplastic left heart syndrome (HLHS)-variant, a complex congenital heart defect (CHD) characterized by the underdevelopment of the left ventricle, presented with complications following single ventricle palliation. Diagnostic work-up revealed elevated Fontan pathway pressures, as well as significant dilation of the inferior Fontan pathway with inefficient swirling flow and hepatic venous reflux. Due to the frail condition of the patient, the clinical team considered an endovascular revision of the Fontan pathway. In this work, we performed a computational fluid dynamics (CFD) analysis informed by data on anatomy, flow, and pressure to investigate the hemodynamic effect of the endovascular Fontan revision. Methods A patient-specific anatomical model of the Fontan pathway was constructed from magnetic resonance imaging (MRI) data using the cardiovascular modeling software CardiovasculaR Integrated Modeling and SimulatiON (CRIMSON). We first created and calibrated a pre-intervention 3D-0D multi-scale model of the patient’s circulation using fluid-structure interaction (FSI) analyses and custom lumped parameter models (LPMs), including the Fontan pathway, the single ventricle, arterial and venous systemic, and pulmonary circulations. Model parameters were iteratively tuned until simulation results matched clinical data on flow and pressure. Following calibration of the pre-intervention model, a custom bifurcated endograft was introduced into the anatomical model to virtually assess post-intervention hemodynamics. Results The pre-intervention model successfully reproduced the clinical hemodynamic data on regional flow splits, pressures, and hepatic venous reflux. The proposed endovascular repair model revealed increases of mean and pulse pressure at the inferior vena cava (IVC) of 6 and 29%, respectively. Inflows at the superior vena cava (SVC) and IVC were each reduced by 5%, whereas outflows at the left pulmonary artery (LPA) and right pulmonary artery (RPA) increased by 4%. Hepatic venous reflux increased by 6%. Conclusion Our computational analysis indicated that the proposed endovascular revision would lead to unfavorable hemodynamic conditions. For these reasons, the clinical team decided to forgo the proposed endovascular repair and to reassess the management of this patient. This study confirms the relevance of CFD modeling as a beneficial tool in surgical planning for single ventricle CHD patients.
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Affiliation(s)
- Yunus Ahmed
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, United States.,Department of Vascular Surgery, Utrecht University, Utrecht, Netherlands
| | | | - Pieter A J van Bakel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, United States.,Department of Vascular Surgery, Utrecht University, Utrecht, Netherlands
| | - Jonathan M Primeaux
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
| | - William J Weadock
- Department of Radiology, University of Michigan, Ann Arbor, MI, United States
| | - Jimmy C Lu
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - Jeffrey D Zampi
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - Arash Salavitabar
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.,Department of Surgery, University of Michigan, Ann Arbor, MI, United States
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21
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A Tribute to Ajit Yoganathan's Cardiovascular Fluid Mechanics Lab: A Survey of Its Contributions to Our Understanding of the Physiology and Management of Single-Ventricle Patients. Cardiovasc Eng Technol 2021; 12:631-639. [PMID: 34018153 DOI: 10.1007/s13239-021-00540-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/30/2021] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Among patients with congenital heart disease, those born with only a single working ventricle represent a particularly complex sub-population, typically requiring multiple surgeries and suffering from high levels of mortality and morbidity. Their cardiac care is complex and has evolved considerably since surgical palliation was first introduced more than 50 years ago. Improvements in treatment have been driven both by growing clinical experience and by knowledge gained through experimental and computational studies of blood flow in these patients. The Cardiovascular Fluid Mechanics Lab at the Georgia Institute of Technology, founded 30 years ago by Dr. Ajit Yoganathan, has pioneered work in this field. METHODS In this review, key contributions of Dr. Yoganathan's Cardiovascular Fluid Dynamics Lab are surveyed, including experimental flow loop studies as well as computational fluid dynamics analyses that address many of the critical challenges that cardiologists and surgeons face in treating these patients, including how to reconstruct cardiovascular anatomy to minimize power loss, balance blood flow distribution at key bifurcation points, and avoid other unfavorable hemodynamic conditions. CONCLUSIONS Among many contributions in this field, work from the Cardiovascular Fluid Mechanics Lab has led to novel medical devices and patient-specific computational modeling workflows and software tools. These key contributions from this group have enhanced our understanding of the physiology and management of single-ventricle patients.
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22
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CRIMSON: An open-source software framework for cardiovascular integrated modelling and simulation. PLoS Comput Biol 2021; 17:e1008881. [PMID: 33970900 PMCID: PMC8148362 DOI: 10.1371/journal.pcbi.1008881] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 05/25/2021] [Accepted: 03/17/2021] [Indexed: 12/16/2022] Open
Abstract
In this work, we describe the CRIMSON (CardiovasculaR Integrated Modelling and SimulatiON) software environment. CRIMSON provides a powerful, customizable and user-friendly system for performing three-dimensional and reduced-order computational haemodynamics studies via a pipeline which involves: 1) segmenting vascular structures from medical images; 2) constructing analytic arterial and venous geometric models; 3) performing finite element mesh generation; 4) designing, and 5) applying boundary conditions; 6) running incompressible Navier-Stokes simulations of blood flow with fluid-structure interaction capabilities; and 7) post-processing and visualizing the results, including velocity, pressure and wall shear stress fields. A key aim of CRIMSON is to create a software environment that makes powerful computational haemodynamics tools accessible to a wide audience, including clinicians and students, both within our research laboratories and throughout the community. The overall philosophy is to leverage best-in-class open source standards for medical image processing, parallel flow computation, geometric solid modelling, data assimilation, and mesh generation. It is actively used by researchers in Europe, North and South America, Asia, and Australia. It has been applied to numerous clinical problems; we illustrate applications of CRIMSON to real-world problems using examples ranging from pre-operative surgical planning to medical device design optimization.
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23
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Is Doppler Echocardiography Adequate for Surgical Planning of Single Ventricle Patients? Cardiovasc Eng Technol 2021; 12:606-617. [PMID: 33931807 DOI: 10.1007/s13239-021-00533-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 03/12/2021] [Indexed: 12/13/2022]
Abstract
PURPOSE Surgical planning has shown great potential for optimizing outcomes for patients affected by single ventricle (SV) malformations. Phase-contrast magnetic resonance imaging (PC-MRI) is the routine technique used for flow acquisition in the surgical planning paradigm. However, PC-MRI may suffer from possible artifacts in certain cases; furthermore, this technology may not be readily available for patients in low and lower-middle-income countries. Therefore, this study aims to investigate the effectiveness of using Doppler echocardiography (echo-Doppler) for flow acquisitions of SV surgical planning. METHODS This study included eight patients whose blood flow data was acquired by both PC-MRI and echo-Doppler. A virtual surgery platform was used to generate two surgical options for each patient: (1) a traditional Fontan conduit and (2) a Y-graft. Computational fluid dynamics (CFD) simulations were conducted using the two flow acquisitions to assess clinically relevant hemodynamic metrics: indexed power loss (iPL) and hepatic flow distribution (HFD). RESULTS Differences exist in flow data acquired by PC-MRI and echo-Doppler, but no statistical significance was obtained. Flow fields, therefore, exhibit discrepancies between simulations using flow acquisitions by PC-MRI and echo-Doppler. In virtual surgery, the two surgical options were ranked based on these metrics. No difference was observed in the ranking of surgical options between using different flow acquisitions. CONCLUSION Doppler echocardiography is an adequate alternative approach to acquire flow data for SV surgical planning. This finding encourages broader usage of SV surgical planning with echo-Doppler when MRI may present artifacts or is not available, especially in low and lower-middle-income countries.
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24
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Kannojiya V, Das AK, Das PK. Simulation of Blood as Fluid: A Review From Rheological Aspects. IEEE Rev Biomed Eng 2021; 14:327-341. [DOI: 10.1109/rbme.2020.3011182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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25
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Guidoboni G, Sacco R, Szopos M, Sala L, Verticchio Vercellin AC, Siesky B, Harris A. Neurodegenerative Disorders of the Eye and of the Brain: A Perspective on Their Fluid-Dynamical Connections and the Potential of Mechanism-Driven Modeling. Front Neurosci 2020; 14:566428. [PMID: 33281543 PMCID: PMC7689058 DOI: 10.3389/fnins.2020.566428] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/19/2020] [Indexed: 01/22/2023] Open
Abstract
Neurodegenerative disorders (NDD) such as Alzheimer's and Parkinson's diseases are significant causes of morbidity and mortality worldwide. The pathophysiology of NDD is still debated, and there is an urgent need to understand the mechanisms behind the onset and progression of these heterogenous diseases. The eye represents a unique window to the brain that can be easily assessed via non-invasive ocular imaging. As such, ocular measurements have been recently considered as potential sources of biomarkers for the early detection and management of NDD. However, the current use of ocular biomarkers in the clinical management of NDD patients is particularly challenging. Specifically, many ocular biomarkers are influenced by local and systemic factors that exhibit significant variation among individuals. In addition, there is a lack of methodology available for interpreting the outcomes of ocular examinations in NDD. Recently, mathematical modeling has emerged as an important tool capable of shedding light on the pathophysiology of multifactorial diseases and enhancing analysis and interpretation of clinical results. In this article, we review and discuss the clinical evidence of the relationship between NDD in the brain and in the eye and explore the potential use of mathematical modeling to facilitate NDD diagnosis and management based upon ocular biomarkers.
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Affiliation(s)
- Giovanna Guidoboni
- Department of Electrical Engineering and Computer Science, Department of Mathematics, University of Missouri, Columbia, MO, United States
| | - Riccardo Sacco
- Department of Mathematics, Politecnico di Milano, Milan, Italy
| | | | | | - Alice Chandra Verticchio Vercellin
- IRCCS - Fondazione Bietti, Rome, Italy.,Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Ophthalmology, University of Pavia, Pavia, Italy
| | - Brent Siesky
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Alon Harris
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection. BIOLOGY 2020; 9:biology9120412. [PMID: 33255292 PMCID: PMC7760396 DOI: 10.3390/biology9120412] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/15/2022]
Abstract
Simple Summary A fluid-structure interaction (FSI) simulation of an intra-atrial Fontan connection was performed. Power loss and pressure drop results fluctuated less during the FSI simulation than during the simulation run with rigid walls, but there were no observable differences in time-averaged pressure drop, connection power loss or hepatic flow distribution. These results suggested that employing a rigid wall is a reasonable assumption when evaluating time-averaged hemodynamic quantities of the Fontan connection under resting breath-held flow conditions. Abstract Total cavopulmonary connection (TCPC) hemodynamics has been hypothesized to be associated with long-term complications in single ventricle heart defect patients. Rigid wall assumption has been commonly used when evaluating TCPC hemodynamics using computational fluid dynamics (CFD) simulation. Previous study has evaluated impact of wall compliance on extra-cardiac TCPC hemodynamics using fluid-structure interaction (FSI) simulation. However, the impact of ignoring wall compliance on the presumably more compliant intra-atrial TCPC hemodynamics is not fully understood. To narrow this knowledge gap, this study aims to investigate impact of wall compliance on an intra-atrial TCPC hemodynamics. A patient-specific model of an intra-atrial TCPC is simulated with an FSI model. Patient-specific 3D TCPC anatomies were reconstructed from transverse cardiovascular magnetic resonance images. Patient-specific vessel flow rate from phase-contrast magnetic resonance imaging (MRI) at the Fontan pathway and the superior vena cava under resting condition were prescribed at the inlets. From the FSI simulation, the degree of wall deformation was compared with in vivo wall deformation from phase-contrast MRI data as validation of the FSI model. Then, TCPC flow structure, power loss and hepatic flow distribution (HFD) were compared between rigid wall and FSI simulation. There were differences in instantaneous pressure drop, power loss and HFD between rigid wall and FSI simulations, but no difference in the time-averaged quantities. The findings of this study support the use of a rigid wall assumption on evaluation of time-averaged intra-atrial TCPC hemodynamic metric under resting breath-held condition.
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27
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Balasubramanian S, Joshi A, Lu JC, Agarwal PP. Advances in Noninvasive Imaging of Patients With Single Ventricle Following Fontan Palliation. Semin Roentgenol 2020; 55:320-329. [PMID: 32859348 DOI: 10.1053/j.ro.2020.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | - Aparna Joshi
- Departments of Radiology, University of Michigan, Ann Arbor, MI
| | - Jimmy C Lu
- Departments of Pediatrics, University of Michigan, Ann Arbor, MI; Departments of Radiology, University of Michigan, Ann Arbor, MI
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28
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Desai MH, Yerebakan C. Commentary: If only we knew when we would fail. J Thorac Cardiovasc Surg 2020; 161:1436-1437. [PMID: 33268127 DOI: 10.1016/j.jtcvs.2020.07.059] [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: 07/18/2020] [Revised: 07/18/2020] [Accepted: 07/20/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Manan H Desai
- Department of Cardiovascular Surgery, Children's National Heart Institute, Children's National Hospital, The George Washington University School of Medicine and Health Sciences, Washington, DC.
| | - Can Yerebakan
- Department of Cardiovascular Surgery, Children's National Heart Institute, Children's National Hospital, The George Washington University School of Medicine and Health Sciences, Washington, DC
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29
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Salavitabar A, Figueroa CA, Lu JC, Owens ST, Axelrod DM, Zampi JD. Emerging 3D technologies and applications within congenital heart disease: teach, predict, plan and guide. Future Cardiol 2020; 16:695-709. [PMID: 32628520 DOI: 10.2217/fca-2020-0004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
3D visualization technologies have evolved to become a mainstay in the management of congenital heart disease (CHD) with a growing presence within multiple facets. Printed and virtual 3D models allow for a more comprehensive approach to educating trainees and care team members. Computational fluid dynamics can take 3D modeling to the next level, by predicting post-procedural outcomes and helping to determine surgical approach. 3D printing and extended reality are developing resources for pre-procedural planning and intra-procedural guidance with the potential to revolutionize decision-making and procedural success. Challenges still remain within existing technologies and their applications to the CHD field. Addressing these gaps, both by those within and outside of CHD, will transform education and patient care within our field.
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Affiliation(s)
- Arash Salavitabar
- C.S. Mott Children's Hospital, University of Michigan Congenital Heart Center, Ann Arbor, MI 48109, USA
| | - C Alberto Figueroa
- Departments of Biomedical Engineering & Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jimmy C Lu
- C.S. Mott Children's Hospital, University of Michigan Congenital Heart Center, Ann Arbor, MI 48109, USA
| | - Sonal T Owens
- C.S. Mott Children's Hospital, University of Michigan Congenital Heart Center, Ann Arbor, MI 48109, USA
| | - David M Axelrod
- Division of Pediatric Cardiology, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Jeffrey D Zampi
- C.S. Mott Children's Hospital, University of Michigan Congenital Heart Center, Ann Arbor, MI 48109, USA
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30
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Ebrahimi P, Youssef D, Salve G, Ayer J, Dehghani F, Fletcher DF, Winlaw DS. Evaluation of personalized right ventricle to pulmonary artery conduits using in silico design and computational analysis of flow. JTCVS OPEN 2020; 1:33-48. [PMID: 36003197 PMCID: PMC9390144 DOI: 10.1016/j.xjon.2020.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 11/09/2019] [Accepted: 02/03/2020] [Indexed: 11/28/2022]
Abstract
Objectives Right ventricle to pulmonary artery (RV-PA) conduits are required for the surgical management of pulmonary atresia with ventricular septal defect and truncus arteriosus. Bioengineered RV-PA connections may address some of the shortcomings of homografts and xenografts, such as lack of growth potential and structural deterioration and may be manufactured to accommodate patient-specific anatomy. The aim of this study was to develop a methodology for in silico patient-specific design and analysis of RV-PA conduits. Methods Cross-sectional imaging was obtained from patients with truncus arteriosus (n = 5) and pulmonary atresia with ventricular septal defect (n = 5) who underwent complete repair with a RV-PA conduit. Three-dimensional models of the heart were constructed by segmentation of the right ventricle, existing conduit, branch pulmonary arteries, and surrounding structures. A customized conduit design for each patient was proposed. Computational fluid dynamics analysis was performed and outputs, including wall shear stress and energy loss, were used to compare the performance of the existing conduits and the customized geometries. Results In this study, a methodology for patient-specific analysis of RV-PA conduit in silico was developed. The results of simulations for 10 patients showed between 23% and 56% decrease in the average wall shear stress and between 24% and 87% reduction in average power requirements in customized designs compared with the stenosed conduits, translating into better hemodynamic performance. Conclusions Creation of an optimal conduit for an individual patient can be achieved using surgeon-guided design and computational fluid dynamics analysis. Manufacture of personalized RV-PA conduits may obviate the need for surgical customization to accommodate existing materials and provide superior long-term outcomes.
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Affiliation(s)
- Pegah Ebrahimi
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
- Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - David Youssef
- Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Gananjay Salve
- Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
| | - Julian Ayer
- Heart Centre for Children, The Children's Hospital at Westmead, Sydney, Australia
- Faculty of Medicine and Health, Discipline of Paediatrics and Child Health, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Fariba Dehghani
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
| | - David F. Fletcher
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
| | - David S. Winlaw
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, Australia
- Faculty of Medicine and Health, Discipline of Paediatrics and Child Health, Sydney Medical School, The University of Sydney, Sydney, Australia
- Address for reprints: David S. Winlaw, MBBS, MD, FRACS, Heart Centre for Children, The Children's Hospital at Westmead, Locked Bag 4001, Corner Hawkesbury Rd and Hainsworth St, Westmead, 2145, Sydney, Australia.
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31
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Mirzaei E, Farahmand M, Kung E. An algorithm for coupling multibranch in vitro experiment to numerical physiology simulation for a hybrid cardiovascular model. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3289. [PMID: 31816194 DOI: 10.1002/cnm.3289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
The hybrid cardiovascular modeling approach integrates an in vitro experiment with a computational lumped-parameter simulation, enabling direct physical testing of medical devices in the context of closed-loop physiology. The interface between the in vitro and computational domains is essential for properly capturing the dynamic interactions of the two. To this end, we developed an iterative algorithm capable of coupling an in vitro experiment containing multiple branches to a lumped-parameter physiology simulation. This algorithm identifies the unique flow waveform solution for each branch of the experiment using an iterative Broyden's approach. For the purpose of algorithm testing, we first used mathematical surrogates to represent the in vitro experiments and demonstrated five scenarios where the in vitro surrogates are coupled to the computational physiology of a Fontan patient. This testing approach allows validation of the coupling result accuracy as the mathematical surrogates can be directly integrated into the computational simulation to obtain the "true solution" of the coupled system. Our algorithm successfully identified the solution flow waveforms in all test scenarios with results matching the true solutions with high accuracy. In all test cases, the number of iterations to achieve the desired convergence criteria was less than 130. To emulate realistic in vitro experiments in which noise contaminates the measurements, we perturbed the surrogate models by adding random noise. The convergence tolerance achievable with the coupling algorithm remained below the magnitudes of the added noise in all cases. Finally, we used this algorithm to couple a physical experiment to the computational physiology model to demonstrate its real-world applicability.
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Affiliation(s)
- Ehsan Mirzaei
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina, USA
| | - Masoud Farahmand
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina, USA
| | - Ethan Kung
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina, USA
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
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Dobutamine stress testing in patients with Fontan circulation augmented by biomechanical modeling. PLoS One 2020; 15:e0229015. [PMID: 32084180 PMCID: PMC7034893 DOI: 10.1371/journal.pone.0229015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 01/28/2020] [Indexed: 02/02/2023] Open
Abstract
Understanding (patho)physiological phenomena and mechanisms of failure in patients with Fontan circulation-a surgically established circulation for patients born with a functionally single ventricle-remains challenging due to the complex hemodynamics and high inter-patient variations in anatomy and function. In this work, we present a biomechanical model of the heart and circulation to augment the diagnostic evaluation of Fontan patients with early-stage heart failure. The proposed framework employs a reduced-order model of heart coupled with a simplified circulation including venous return, creating a closed-loop system. We deploy this framework to augment the information from data obtained during combined cardiac catheterization and magnetic resonance exams (XMR), performed at rest and during dobutamine stress in 9 children with Fontan circulation and 2 biventricular controls. We demonstrate that our modeling framework enables patient-specific investigation of myocardial stiffness, contractility at rest, contractile reserve during stress and changes in vascular resistance. Hereby, the model allows to identify key factors underlying the pathophysiological response to stress in these patients. In addition, the rapid personalization of the model to patient data and fast simulation of cardiac cycles make our framework directly applicable in a clinical workflow. We conclude that the proposed modeling framework is a valuable addition to the current clinical diagnostic XMR exam that helps to explain patient-specific stress hemodynamics and can identify potential mechanisms of failure in patients with Fontan circulation.
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Tossas-Betancourt C, van Bakel TMJ, Arthurs CJ, Coleman DM, Eliason JL, Figueroa CA, Stanley JC. Computational analysis of renal artery flow characteristics by modeling aortoplasty and aortic bypass interventions for abdominal aortic coarctation. J Vasc Surg 2020; 71:505-516.e4. [PMID: 31153701 PMCID: PMC8409007 DOI: 10.1016/j.jvs.2019.02.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/20/2019] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Suprarenal abdominal aortic coarctation (SAAC) alters flow and pressure patterns to the kidneys and is often associated with severe angiotensin-mediated hypertension refractory to drug therapy. SAAC is most often treated by a thoracoabdominal bypass (TAB) or patch aortoplasty (PA). It is currently unclear what effect these interventions have on renal flow and pressure waveforms. This study, using retrospective data from a patient with SAAC subjected to a TAB, undertook computational modeling to analyze aortorenal blood flow preoperatively as well as postoperatively after a variety of TAB and PA interventions. METHODS Patient-specific anatomic models were constructed from preoperative computed tomography angiograms of a 9-year-old child with an isolated SAAC. Fluid-structure interaction (FSI) simulations of hemodynamics were performed to analyze preoperative renal flow and pressure waveforms. A parametric study was then performed to examine the hemodynamic impact of different bypass diameters and patch oversizing. RESULTS Preoperative FSI results documented diastole-dominated renal perfusion with considerable high-frequency disturbances in blood flow and pressure. The postoperative TAB right and left kidney volumes increased by 58% and 79%, respectively, reflecting the increased renal artery blood flows calculated by the FSI analysis. Postoperative increases in systolic flow accompanied decreases in high-frequency disturbances, aortic pressure, and collateral flow after all surgical interventions. In general, lesser degrees of high-frequency disturbances followed PA interventions. High-frequency disturbances were eliminated with the 0% PA in contrast to the 30% and 50% PA oversizing and TAB interventions, in which these flow disturbances remained. CONCLUSIONS Both TAB and PA dramatically improved renal artery flow and pressure waveforms, although disturbed renal waveforms remained in many of the surgical scenarios. Importantly, only the 0% PA oversizing scenario eliminated all high-frequency disturbances, resulting in nearly normal aortorenal blood flow. The study also establishes the relevance of patient-specific computational modeling in planning interventions for the midaortic syndrome.
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Affiliation(s)
| | | | - Christopher J Arthurs
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Dawn M Coleman
- Department of Surgery, University of Michigan, Ann Arbor, Mich
| | | | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Mich; Department of Surgery, University of Michigan, Ann Arbor, Mich.
| | - James C Stanley
- Department of Surgery, University of Michigan, Ann Arbor, Mich
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Liu Z, Yang G, Nan S, Qi Y, Pang Y, Shi Y. The effect of anastomotic angle and diameter ratio on flow field in the distal end-to-side anastomosis. Proc Inst Mech Eng H 2019; 234:377-386. [PMID: 31826710 DOI: 10.1177/0954411919894410] [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: 11/15/2022]
Abstract
Flow fields in the distal end-to-side anastomosis of coronary artery bypass graft are associated with intimal hyperplasia and bypass failure. This work aims to demonstrate the effect of anastomotic angle and diameter ratio on flow field of coronary artery bypass graft. The flow fields inside polydimethylsiloxane models of coronary artery bypass graft with various anastomotic angles (α = 30°, 45°, 60° and 75°) and different diameter ratios (Φ = 0.78 and 1.11) are investigated using particle image velocimetry and computational fluid dynamics method under pulsatile flow condition. The results show that the anastomotic angle is positively correlated with the number and area of the recirculation zone, and the flow field disturbance at the anastomosis will develop in the same direction. Compared with that of Φ = 0.78, when Φ = 1.11, the flow fields at the anastomosis are relatively smoother with less turbulence.
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Affiliation(s)
- Zhaomiao Liu
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China
| | - Gang Yang
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China
| | - Siqi Nan
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China
| | - Yipeng Qi
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China
| | - Yan Pang
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China
| | - Yi Shi
- Department of Cardiac Surgery, FuWai Hospital, Chinese Academy of Medical Sciences, Beijing, China
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Algabri YA, Altwijri O, Chatpun S. Visualization of Blood Flow in AAA Patient-Specific Geometry: 3-D Reconstruction and Simulation Procedures. BIONANOSCIENCE 2019. [DOI: 10.1007/s12668-019-00662-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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36
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CardioFAN: open source platform for noninvasive assessment of pulse transit time and pulsatile flow in hyperelastic vascular networks. Biomech Model Mechanobiol 2019; 18:1529-1548. [PMID: 31076923 DOI: 10.1007/s10237-019-01163-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 04/26/2019] [Indexed: 01/08/2023]
Abstract
A profound analysis of pressure and flow wave propagation in cardiovascular systems is the key in noninvasive assessment of hemodynamic parameters. Pulse transit time (PTT), which closely relates to the physical properties of the cardiovascular system, can be linked to variations of blood pressure and stroke volume to provide information for patient-specific clinical diagnostics. In this work, we present mathematical and numerical tools, capable of accurately predicting the PTT, local pulse wave velocity, vessel compliance, and pressure/flow waveforms, in a viscous hyperelastic cardiovascular network. A new one-dimensional framework, entitled cardiovascular flow analysis (CardioFAN), is presented to describe the pulsatile fluid-structure interaction in the hyperelastic arteries, where pertaining hyperbolic equations are solved using a high-resolution total variation diminishing Lax-Wendroff method. The computational algorithm is validated against well-known numerical, in vitro and in vivo data for networks of main human arteries with 55, 37 and 26 segments, respectively. PTT prediction is improved by accounting for hyperelastic nonlinear waves between two arbitrary sections of the arterial tree. Consequently, arterial compliance assignments at each segment are improved in a personalized model of the human aorta and supra-aortic branches with 26 segments, where prior in vivo data were available for comparison. This resulted in a 1.5% improvement in overall predictions of the waveforms, or average relative errors of 5.5% in predicting flow, luminal area and pressure waveforms compared to prior in vivo measurements. The open source software, CardioFAN, can be calibrated for arbitrary patient-specific vascular networks to conduct noninvasive diagnostics.
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Computational study on hemodynamic changes in patient-specific proximal neck angulation of abdominal aortic aneurysm with time-varying velocity. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:181-190. [PMID: 30762222 DOI: 10.1007/s13246-019-00728-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 01/21/2019] [Indexed: 12/27/2022]
Abstract
Aneurysms are considered as a critical cardiovascular disease worldwide when they rupture. The clinical understanding of geometrical impact on the flow behaviour and biomechanics of abdominal aortic aneurysm (AAA) is progressively developing. Proximal neck angulations of AAAs are believed to influence the hemodynamic changes and wall shear stress (WSS) within AAAs. Our aim was to perform pulsatile simulations using computational fluid dynamics (CFD) for patient-specific geometry to investigate the influence of severe angular (≥ 60°) neck on AAA's hemodynamic and wall shear stress. The patient's geometrical characteristics were obtained from a computed tomography images database of AAA patients. The AAA geometry was reconstructed using Mimics software. In computational method, blood was assumed Newtonian fluid and an inlet varying velocity waveform in a cardiac cycle was assigned. The CFD study was performed with ANSYS software. The results of flow behaviours indicated that the blood flow through severe bending of angular neck leads to high turbulence and asymmetry of flows within the aneurysm sac resulting in blood recirculation. The high wall shear stress (WSS) occurred near the AAA neck and on surface of aneurysm sac. This study explained and showed flow behaviours and WSS progression within high angular neck AAA and risk prediction of abdominal aorta rupture. We expect that the visualization of blood flow and hemodynamic changes resulted from CFD simulation could be as an extra tool to assist clinicians during a decision making when estimation the risks of interventional procedures.
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van Bakel TMJ, Grassi V, Patel HJ, Trimarchi S. Commentary: Dynamic Mesenteric Malperfusion in Aortic Dissection. J Endovasc Ther 2018; 26:88-89. [PMID: 30580696 DOI: 10.1177/1526602818820589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Theodorus M J van Bakel
- 1 Department of Surgery, University of Michigan, Ann Arbor, MI, USA.,2 Department of Vascular Surgery, University Medical Center Utrecht, the Netherlands.,3 Policlinico San Donato IRCCS, Thoracic Aortic Research Center, San Donato Milanese, Italy
| | - Viviana Grassi
- 4 Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Milan, Italy
| | - Himanshu J Patel
- 5 Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Santi Trimarchi
- 6 Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Milan, Italy.,7 Department of Scienze Biomediche per la Salute, University of Milan, Italy
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Uncertainty Quantification for Non-invasive Assessment of Pressure Drop Across a Coarctation of the Aorta Using CFD. Cardiovasc Eng Technol 2018; 9:582-596. [PMID: 30284186 DOI: 10.1007/s13239-018-00381-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/25/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE Numerical assessment of the pressure drop across an aortic coarctation using CFD is a promising approach to replace invasive catheter-based measurements. The aim of this study was to investigate and quantify the uncertainty of numerical calculation of the pressure drop introduced during two essential steps of medical image processing: segmentation of the patient-specific geometry and measurement of patient-specific flow rates from 4D-flow-MRI. METHODS Based on the baseline segmentation, geometries with different stenosis diameters were generated for a sample of ten patients. The pressure drop generated by these geometries was calculated for different volume flow rates using computational fluid dynamics. Based on these simulations, a second order polynomial fit was calculated. Based on these polynomial fits an uncertainty of pressure drop calculation was quantified. RESULTS The calculated pressure drop values varied strongly between the patients. In four patients, pressure drops above and below the clinical threshold of 20 mmHg were found. The median standard deviation of the pressure drop was 2.3 mmHg. The sensitivity of the pressure drop toward changes in the volume flow rate or the stenosis geometry varied between patients. CONCLUSION The uncertainty of numerical pressure drop calculation introduced by uncertainties during image segmentation and measurement of volume flow rates was comparable to the uncertainty of pressure drop measurements using invasive catheterization. However, in some patients this uncertainty would have led to different treatment decision. Therefore, patient-specific uncertainty assessment might help to better understand the reliability of a numerically calculated biomarker as the pressure drop across an aortic coarctation.
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van Bakel TM, de Beaufort HW, Trimarchi S, Marrocco-Trischitta MM, Bismuth J, Moll FL, Patel HJ, van Herwaarden JA. Status of branched endovascular aortic arch repair. Ann Cardiothorac Surg 2018; 7:406-413. [PMID: 30155420 PMCID: PMC6094020 DOI: 10.21037/acs.2018.03.13] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/13/2018] [Indexed: 11/06/2022]
Abstract
Multiple medical device manufacturers are developing branched endografts for thoracic endovascular aortic repair (TEVAR), to provide a minimally invasive alternative for the treatment of aortic arch pathologies in patients who are deemed unfit for open or hybrid arch repair. Different branched endografts have been introduced, with varying number, size and orientation of the branches that redirect flow to the supra-aortic arteries. We present an overview of the currently investigated devices and review their outcomes. The results of branched TEVAR are promising, yet stroke remains the predominant periprocedural concern. For now, these procedures should be limited to select expert centers where the design and deployment procedure of branched endografts can be further developed to reduce the risk of stroke.
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Affiliation(s)
- Theodorus M. van Bakel
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
- Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, San Donato Milanese, Italy
- Department of Surgery, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, USA
| | - Hector W. de Beaufort
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
- Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, San Donato Milanese, Italy
| | - Santi Trimarchi
- Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, San Donato Milanese, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | | | - Jean Bismuth
- Houston Methodist DeBakey Heart & Vascular Center, Houston, TX, USA
| | - Frans L. Moll
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Himanshu J. Patel
- Department of Cardiac Surgery, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, USA
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Clinical Applications of Patient-Specific Models: The Case for a Simple Approach. J Cardiovasc Transl Res 2018; 11:71-79. [PMID: 29453747 DOI: 10.1007/s12265-018-9787-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 01/05/2018] [Indexed: 01/08/2023]
Abstract
Over the past several decades, increasingly sophisticated models of the heart have provided important insights into cardiac physiology and are increasingly used to predict the impact of diseases and therapies on the heart. In an era of personalized medicine, many envision patient-specific computational models as a powerful tool for personalizing therapy. Yet the complexity of current models poses important challenges, including identifying model parameters and completing calculations quickly enough for routine clinical use. We propose that early clinical successes are likely to arise from an alternative approach: relatively simple, fast, phenomenologic models with a small number of parameters that can be easily (and automatically) customized. We discuss examples of simple yet foundational models that have already made a tremendous impact on clinical education and practice, and make the case that reducing rather than increasing model complexity may be the key to realizing the promise of patient-specific modeling for clinical applications.
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