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Kjeldsberg HA, Albors C, Mill J, Medel DV, Camara O, Sundnes J, Valen-Sendstad K. Impact of left atrial wall motion assumptions in fluid simulations on proposed predictors of thrombus formation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3825. [PMID: 38629309 DOI: 10.1002/cnm.3825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 02/18/2024] [Accepted: 04/05/2024] [Indexed: 06/11/2024]
Abstract
Atrial fibrillation (AF) poses a significant risk of stroke due to thrombus formation, which primarily occurs in the left atrial appendage (LAA). Medical image-based computational fluid dynamics (CFD) simulations can provide valuable insight into patient-specific hemodynamics and could potentially enhance personalized assessment of thrombus risk. However, the importance of accurately representing the left atrial (LA) wall dynamics has not been fully resolved. In this study, we compared four modeling scenarios; rigid walls, a generic wall motion based on a reference motion, a semi-generic wall motion based on patient-specific motion, and patient-specific wall motion based on medical images. We considered a LA geometry acquired from 4D computed tomography during AF, systematically performed convergence tests to assess the numerical accuracy of our solution strategy, and quantified the differences between the four approaches. The results revealed that wall motion had no discernible impact on LA cavity hemodynamics, nor on the markers that indicate thrombus formation. However, the flow patterns within the LAA deviated significantly in the rigid model, indicating that the assumption of rigid walls may lead to errors in the estimated risk factors. In contrast, the generic, semi-generic, and patient-specific cases were qualitatively similar. The results highlight the crucial role of wall motion on hemodynamics and predictors of thrombus formation, and also demonstrate the potential of using a generic motion model as a surrogate for the more complex patient-specific motion. While the present study considered a single case, the employed CFD framework is entirely open-source and designed for adaptability, allowing for integration of additional models and generic motions.
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Affiliation(s)
- Henrik A Kjeldsberg
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Carlos Albors
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Jordi Mill
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | | | - Oscar Camara
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Joakim Sundnes
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
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2
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Danielli F, Berti F, Fanni BM, Gasparotti E, Celi S, Pennati G, Petrini L. Left atrial appendage occlusion: On the need of a numerical model to simulate the implant procedure. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3814. [PMID: 38504482 DOI: 10.1002/cnm.3814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/23/2024] [Accepted: 03/10/2024] [Indexed: 03/21/2024]
Abstract
Left atrial appendage occlusion (LAAO) is a percutaneous procedure to prevent thromboembolism in patients affected by atrial fibrillation. Despite its demonstrated efficacy, the LAA morphological complexity hinders the procedure, resulting in postprocedural drawbacks (device-related thrombus and peri-device leakage). Local anatomical features may cause difficulties in the device's positioning and affect the effectiveness of the device's implant. The current work proposes a detailed FE model of the LAAO useful to investigate implant scenarios and derive clinical indications. A high-fidelity model of the Watchman FLX device and simplified parametric conduits mimicking the zone of the LAA where the device is deployed were developed. Device-conduit interactions were evaluated by looking at clinical indicators such as device-wall gap, possible cause of leakage, and device protrusion. As expected, the positioning of the crimped device before the deployment was found to significantly affect the implant outcomes: clinician's choices can be improved if FE models are used to optimize the pre-operative planning. Remarkably, also the wall mechanical stiffness plays an important role. However, this parameter value is unknown for a specific LAA, a crucial point that must be correctly defined for developing an accurate FE model. Finally, numerical simulations outlined how the device's configuration on which the clinician relies to assess the implant success (i.e., the deployed configuration with the device still attached to the catheter) may differ from the actual final device's configuration, relevant for achieving a safe intervention.
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Affiliation(s)
- Francesca Danielli
- LaBS - Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Francesca Berti
- LaBS - Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | | | | | - Simona Celi
- BioCardioLab, Fondazione Toscana G. Monasterio, Massa, Italy
| | - Giancarlo Pennati
- LaBS - Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Lorenza Petrini
- Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy
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Khalili E, Daversin-Catty C, Olivares AL, Mill J, Camara O, Valen-Sendstad K. On the importance of fundamental computational fluid dynamics toward a robust and reliable model of left atrial flows. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3804. [PMID: 38286150 DOI: 10.1002/cnm.3804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/31/2023] [Accepted: 01/07/2024] [Indexed: 01/31/2024]
Abstract
Computational fluid dynamics (CFD) studies of left atrial flows have reached a sophisticated level, for example, revealing plausible relationships between hemodynamics and stresses with atrial fibrillation. However, little focus has been on fundamental fluid modeling of LA flows. The purpose of this study was to investigate the spatiotemporal convergence, along with the differences between high- (HR) versus normal-resolution/accuracy (NR) solution strategies, respectively. Rigid wall CFD simulations were conducted on 12 patient-specific left atrial geometries obtained from computed tomography scans, utilizing a second-order accurate and space/time-centered solver. The convergence studies showed an average variability of around 30% and 55% for time averaged wall shear stress (WSS), oscillatory shear index (OSI), relative residence time (RRT), and endothelial cell activation potential (ECAP), even between intermediate spatial and temporal resolutions, in the left atrium (LA) and left atrial appendage (LAA), respectively. The comparison between HR and NR simulations showed good correlation in the LA for WSS, RRT, and ECAP (R 2 > .9 ), but not for OSI (R 2 = .63 ). However, there were poor correlations in the LAA especially for OSI, RRT, and ECAP (R 2 = .55, .63, and .61, respectively), except for WSS (R 2 = .81 ). The errors are comparable to differences previously reported with disease correlations. To robustly predict atrial hemodynamics and stresses, numerical resolutions of 10 M elements (i.e., Δ x = ∼ .5 mm) and 10 k time-steps per cycle seem necessary (i.e., one order of magnitude higher than normally used in both space and time). In conclusion, attention to fundamental numerical aspects is essential toward establishing a plausible, robust, and reliable model of LA flows.
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Affiliation(s)
- Ehsan Khalili
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Cécile Daversin-Catty
- Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Andy L Olivares
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Jordi Mill
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Oscar Camara
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
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Mill J, Harrison J, Saiz-Vivo M, Albors C, Morales X, Olivares AL, Iriart X, Cochet H, Noailly J, Sermesant M, Camara O. The role of the pulmonary veins on left atrial flow patterns and thrombus formation. Sci Rep 2024; 14:5860. [PMID: 38467726 DOI: 10.1038/s41598-024-56658-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/08/2024] [Indexed: 03/13/2024] Open
Abstract
Atrial fibrillation (AF) is the most common human arrhythmia, forming thrombi mostly in the left atrial appendage (LAA). However, the relation between LAA morphology, blood patterns and clot formation is not yet fully understood. Furthermore, the impact of anatomical structures like the pulmonary veins (PVs) have not been thoroughly studied due to data acquisition difficulties. In-silico studies with flow simulations provide a detailed analysis of blood flow patterns under different boundary conditions, but a limited number of cases have been reported in the literature. To address these gaps, we investigated the influence of PVs on LA blood flow patterns and thrombus formation risk through computational fluid dynamics simulations conducted on a sizeable cohort of 130 patients, establishing the largest cohort of patient-specific LA fluid simulations reported to date. The investigation encompassed an in-depth analysis of several parameters, including pulmonary vein orientation (e.g., angles) and configuration (e.g., number), LAA and LA volumes as well as their ratio, flow, and mass-less particles. Our findings highlight the total number of particles within the LAA as a key parameter for distinguishing between the thrombus and non-thrombus groups. Moreover, the angles between the different PVs play an important role to determine the flow going inside the LAA and consequently the risk of thrombus formation. The alignment between the LAA and the main direction of the left superior pulmonary vein, or the position of the right pulmonary vein when it exhibits greater inclination, had an impact to distinguish the control group vs. the thrombus group. These insights shed light on the intricate relationship between PV configuration, LAA morphology, and thrombus formation, underscoring the importance of comprehensive blood flow pattern analyses.
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Affiliation(s)
- Jordi Mill
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain.
| | - Josquin Harrison
- Inria, Université Côte d'Azur, Epione team, 06902, Sophia Antipolis, France
| | - Marta Saiz-Vivo
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - Carlos Albors
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - Xabier Morales
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - Andy L Olivares
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - Xavier Iriart
- IHU Liryc, CHU Bordeaux, Université Bordeaux, Inserm, 33600, Pessac, France
- Bordeaux University Hospital, 33600, Bordeaux, France
| | - Hubert Cochet
- IHU Liryc, CHU Bordeaux, Université Bordeaux, Inserm, 33600, Pessac, France
- Bordeaux University Hospital, 33600, Bordeaux, France
| | - Jerome Noailly
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - Maxime Sermesant
- Inria, Université Côte d'Azur, Epione team, 06902, Sophia Antipolis, France
| | - Oscar Camara
- Physense, BCN Medtech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
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Telle Å, Bargellini C, Chahine Y, Del Álamo JC, Akoum N, Boyle PM. Personalized biomechanical insights in atrial fibrillation: opportunities & challenges. Expert Rev Cardiovasc Ther 2023; 21:817-837. [PMID: 37878350 PMCID: PMC10841537 DOI: 10.1080/14779072.2023.2273896] [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: 08/12/2023] [Accepted: 10/18/2023] [Indexed: 10/26/2023]
Abstract
INTRODUCTION Atrial fibrillation (AF) is an increasingly prevalent and significant worldwide health problem. Manifested as an irregular atrial electrophysiological activation, it is associated with many serious health complications. AF affects the biomechanical function of the heart as contraction follows the electrical activation, subsequently leading to reduced blood flow. The underlying mechanisms behind AF are not fully understood, but it is known that AF is highly correlated with the presence of atrial fibrosis, and with a manifold increase in risk of stroke. AREAS COVERED In this review, we focus on biomechanical aspects in atrial fibrillation, current and emerging use of clinical images, and personalized computational models. We also discuss how these can be used to provide patient-specific care. EXPERT OPINION Understanding the connection betweenatrial fibrillation and atrial remodeling might lead to valuable understanding of stroke and heart failure pathophysiology. Established and emerging imaging modalities can bring us closer to this understanding, especially with continued advancements in processing accuracy, reproducibility, and clinical relevance of the associated technologies. Computational models of cardiac electromechanics can be used to glean additional insights on the roles of AF and remodeling in heart function.
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Affiliation(s)
- Åshild Telle
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Clarissa Bargellini
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Yaacoub Chahine
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Juan C Del Álamo
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
| | - Nazem Akoum
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Division of Cardiology, University of Washington, Seattle, WA, USA
| | - Patrick M Boyle
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
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Uncertainty Quantification in the In Vivo Image-Based Estimation of Local Elastic Properties of Vascular Walls. J Cardiovasc Dev Dis 2023; 10:jcdd10030109. [PMID: 36975873 PMCID: PMC10058982 DOI: 10.3390/jcdd10030109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/15/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Introduction: Patient-specific computational models are a powerful tool for planning cardiovascular interventions. However, the in vivo patient-specific mechanical properties of vessels represent a major source of uncertainty. In this study, we investigated the effect of uncertainty in the elastic module (E) on a Fluid–Structure Interaction (FSI) model of a patient-specific aorta. Methods: The image-based χ-method was used to compute the initial E value of the vascular wall. The uncertainty quantification was carried out using the generalized Polynomial Chaos (gPC) expansion technique. The stochastic analysis was based on four deterministic simulations considering four quadrature points. A deviation of about ±20% on the estimation of the E value was assumed. Results: The influence of the uncertain E parameter was evaluated along the cardiac cycle on area and flow variations extracted from five cross-sections of the aortic FSI model. Results of stochastic analysis showed the impact of E in the ascending aorta while an insignificant effect was observed in the descending tract. Conclusions: This study demonstrated the importance of the image-based methodology for inferring E, highlighting the feasibility of retrieving useful additional data and enhancing the reliability of in silico models in clinical practice.
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Qureshi A, Lip GYH, Nordsletten DA, Williams SE, Aslanidi O, de Vecchi A. Imaging and biophysical modelling of thrombogenic mechanisms in atrial fibrillation and stroke. Front Cardiovasc Med 2023; 9:1074562. [PMID: 36733827 PMCID: PMC9887999 DOI: 10.3389/fcvm.2022.1074562] [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: 10/19/2022] [Accepted: 12/29/2022] [Indexed: 01/18/2023] Open
Abstract
Atrial fibrillation (AF) underlies almost one third of all ischaemic strokes, with the left atrial appendage (LAA) identified as the primary thromboembolic source. Current stroke risk stratification approaches, such as the CHA2DS2-VASc score, rely mostly on clinical comorbidities, rather than thrombogenic mechanisms such as blood stasis, hypercoagulability and endothelial dysfunction-known as Virchow's triad. While detection of AF-related thrombi is possible using established cardiac imaging techniques, such as transoesophageal echocardiography, there is a growing need to reliably assess AF-patient thrombogenicity prior to thrombus formation. Over the past decade, cardiac imaging and image-based biophysical modelling have emerged as powerful tools for reproducing the mechanisms of thrombogenesis. Clinical imaging modalities such as cardiac computed tomography, magnetic resonance and echocardiographic techniques can measure blood flow velocities and identify LA fibrosis (an indicator of endothelial dysfunction), but imaging remains limited in its ability to assess blood coagulation dynamics. In-silico cardiac modelling tools-such as computational fluid dynamics for blood flow, reaction-diffusion-convection equations to mimic the coagulation cascade, and surrogate flow metrics associated with endothelial damage-have grown in prevalence and advanced mechanistic understanding of thrombogenesis. However, neither technique alone can fully elucidate thrombogenicity in AF. In future, combining cardiac imaging with in-silico modelling and integrating machine learning approaches for rapid results directly from imaging data will require development under a rigorous framework of verification and clinical validation, but may pave the way towards enhanced personalised stroke risk stratification in the growing population of AF patients. This Review will focus on the significant progress in these fields.
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Affiliation(s)
- Ahmed Qureshi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom,*Correspondence: Ahmed Qureshi,
| | - Gregory Y. H. Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, United Kingdom
| | - David A. Nordsletten
- School of Biomedical Engineering and Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom,Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
| | - Steven E. Williams
- School of Biomedical Engineering and Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom,Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | - Oleg Aslanidi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom
| | - Adelaide de Vecchi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, St. Thomas’ Hospital, London, United Kingdom
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Alinezhad L, Ghalichi F, Ahmadlouydarab M, Chenaghlou M. Left atrial appendage shape impacts on the left atrial flow hemodynamics: A numerical hypothesis generating study on two cases. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 213:106506. [PMID: 34752960 DOI: 10.1016/j.cmpb.2021.106506] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND OBJECTIVES The left atrial appendage (LAA) is the most common region for thrombus formation in atrial fibrillation (AF). Morphological parameters such as shape, size, and LAA volume can cause insufficient effectiveness of available therapeutic options. This study aimed to examine blood flow inside LAA and its removal effects. Computational fluid dynamic (CFD) simulations were carried out on two patients with different morphologies. METHODS Two patients' CT was used to reconstruct the 3D geometries of the left atrium (LA) and left atrial appendage (LAA). Then, the geometries were refined in the mentioned software, and the LAA in some models was removed. Next, in generated 3D volume mesh, sinus rhythm (SR) and atrial fibrillation (AF) outflow velocity were imposed at the mitral valve as boundary conditions. Finally, CFD simulation was conducted to analyzing blood flow within LA with/without LA. RESULTS The results confirmed that velocity and vorticity decreased under AF conditions inside the LA domain for both patients. However, removing LAA may cause unpredictable consequences, due to different shape and volume of LAA. LAA removal had insignificant effects on velocity and vorticity within LA in SR-mitral outflow. However, removing LAA increased the blood flow rate by 9.15% and vorticity by 7.27% for patient one under AF rhythm (SR)-outflow. In contrast, for patient two, LAA removal in both AF and SR decreased velocity and vorticity within the LA domain. In SR-mitral outflow, velocity dropped by 18.8 %, and vorticity by 13.2%. Also, under AF velocity and vorticity decreased by 23.33% and 18.6% respectively. Meanwhile, the results indicated that the vorticity magnitude increased inside the LAA under AF associated with the risk of thrombus formation, particularly for patient one under AF. The distal part of LAA in both patients was the most common region for blood stasis because of the lowest velocity magnitude. CONCLUSION Overall, the morphology of LAA could be the critical parameter to determine the possibility of thrombosis formation, particularly under AF conditions. High volume, low blood flow velocity and two-lobe-appendage are more likely to have blood stasis. Furthermore, the morphology difference can affect the LAA removal result and make it more complicated. So, it could be challenging to generalize LAA removal as a therapeutic option for different patients. The implication of this CFD observation needs more investigation.
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Affiliation(s)
- Lida Alinezhad
- Department of Biomedical Engineering, Division of Biomechanics, Sahand University of Technology, Tabriz, Iran
| | - Farzan Ghalichi
- Department of Biomedical Engineering, Division of Biomechanics, Sahand University of Technology, Tabriz, Iran
| | - Majid Ahmadlouydarab
- Faculty of Chemical & Petroleum Engineering, University of Tabriz, Tabriz, Iran.
| | - Maryam Chenaghlou
- Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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9
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Celi S, Gasparotti E, Capellini K, Vignali E, Fanni BM, Ali LA, Cantinotti M, Murzi M, Berti S, Santoro G, Positano V. 3D Printing in Modern Cardiology. Curr Pharm Des 2021; 27:1918-1930. [PMID: 32568014 DOI: 10.2174/1381612826666200622132440] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/05/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND 3D printing represents an emerging technology in the field of cardiovascular medicine. 3D printing can help to perform a better analysis of complex anatomies to optimize intervention planning. METHODS A systematic review was performed to illustrate the 3D printing technology and to describe the workflow to obtain 3D printed models from patient-specific images. Examples from our laboratory of the benefit of 3D printing in planning interventions were also reported. RESULTS 3D printing technique is reliable when applied to high-quality 3D image data (CTA, CMR, 3D echography), but it still needs the involvement of expert operators for image segmentation and mesh refinement. 3D printed models could be useful in interventional planning, although prospective studies with comprehensive and clinically meaningful endpoints are required to demonstrate the clinical utility. CONCLUSION 3D printing can be used to improve anatomy understanding and surgical planning.
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Affiliation(s)
- Simona Celi
- BioCardioLab, Fondazione Toscana "G. Monasterio", Massa, Italy
| | | | - Katia Capellini
- BioCardioLab, Fondazione Toscana "G. Monasterio", Massa, Italy
| | | | - Benigno M Fanni
- BioCardioLab, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Lamia A Ali
- Pediatric Cardiology Unit, Fondazione Toscana "G. Monasterio" Massa, Italy
| | | | - Michele Murzi
- Adult Cardiosurgery Unit, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Sergio Berti
- Adult Interventional Cardiology Unit, Fondazione Toscana "G. Monasterio", Massa, Italy
| | - Giuseppe Santoro
- Pediatric Cardiology Unit, Fondazione Toscana "G. Monasterio" Massa, Italy
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10
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Loureiro-Ga M, Veiga C, Fdez-Manin G, Jimenez VA, Juan-Salvadores P, Busto L, Baz JA, Iñiguez A. Predicting TAVI paravalvular regurgitation outcomes based on numerical simulation of the aortic annulus eccentricity and perivalvular areas. Comput Methods Biomech Biomed Engin 2021; 24:1629-1637. [PMID: 33779444 DOI: 10.1080/10255842.2021.1906233] [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: 10/21/2022]
Abstract
Trans-catheter aortic valve implantation (TAVI) is an increasingly adopted technique which provides a minimal invasive solution for patients who suffer from severe aortic stenosis. Some complications of the procedure could be annular rupture or paravalvular leakage, both related with adverse outcome. In TAVI with balloon expandable devices, a mismatch between those two factors leads to a conflict situation, where improving one worsens the other. The presented research proposes a methodology that uses numerical simulation to obtain certain TAVI outcomes related with aortic regurgitation due to paravalvular leakage, such as perivalvular area, aortic eccentricity or annular pressure. The application of the methodology for two patients shows the possibility of predicting those quantities. The highest stress values are distributed along the contact area. Results also show that a great deformation on the aortic annulus does not necessarily imply a higher stress; pressure can either be converted into root reshape or into root stretching. Validation of the results was done using scientific publications, clinical guidelines and clinical reports. Numerical simulation provides a suitable tool that could possibly contribute to optimize the planification procedure adjusting the mismatch between size and pressure.
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Affiliation(s)
- Marcos Loureiro-Ga
- Cardiology Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain.,Department of Applied Mathematics II, University of Vigo, Vigo, Spain
| | - Cesar Veiga
- Cardiology Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | | | | | - Pablo Juan-Salvadores
- Cardiology Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | - Laura Busto
- Cardiology Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, Vigo, Spain
| | - Jose Antonio Baz
- Cardiology Department, Complexo Hospitalario Universitario de Vigo (CHUVI), Vigo, Spain
| | - Andrés Iñiguez
- Cardiology Department, Complexo Hospitalario Universitario de Vigo (CHUVI), Vigo, Spain
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11
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Impact of left atrial appendage location on risk of thrombus formation in patients with atrial fibrillation. Biomech Model Mechanobiol 2021; 20:1431-1443. [PMID: 33755847 DOI: 10.1007/s10237-021-01454-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/10/2021] [Indexed: 02/07/2023]
Abstract
Most strokes in patients with atrial fibrillation (AF) are thought to arise from thrombus formation in the left atrial appendage (LAA). Assessing the hemodynamics in LAA and left atrium (LA) may provide some insights in the evaluation of the risk of thrombus formation. This study aims to find out the impact of different LAA locations with respect of LA on the risk of thrombus formation within LAA in patients with AF. Three different LAA locations at LA were modeled and a fully coupled fluid-structure interaction analysis was performed. A discrete phase method was used for particle residence analysis to evaluate risk of the thrombus formation. The results showed that LAA positions on the LA affected the LAA flow velocity distribution, passive contraction ability, and particle residence. In particular, the left pulmonary veins (PVs) had a greater influence on the LAA hemodynamics than the right PVs. The LAA had the lowest contractibility when it was located between left superior and left inferior PVs, and in this case, a larger number of particles were resided, which indicated a higher risk of thrombus formation. The present work provides a quantitative way to evaluate the risk of thrombus formation within LAA in patients with AF.
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12
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Vignali E, di Bartolo F, Gasparotti E, Malacarne A, Concistré G, Chiaramonti F, Murzi M, Positano V, Landini L, Celi S. Correlation between micro and macrostructural biaxial behavior of ascending thoracic aneurysm: a novel experimental technique. Med Eng Phys 2020; 86:78-85. [PMID: 33261737 DOI: 10.1016/j.medengphy.2020.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 10/01/2020] [Accepted: 10/21/2020] [Indexed: 02/08/2023]
Abstract
Mechanical properties and microstructural modifications of vessel tissues are strongly linked, as established in the state of the art of cardiovascular diseases. Techniques to obtain both mechanical and structural information are reported, but the possibility to obtain real-time microstructural and macrostructural data correlated is still lacking. An experimental approach to characterize the aortic tissue is presented. A setup integrating biaxial traction and Small Angle Light Scattering (SALS) analysis is described. The system was adopted to test ex-vivo aorta specimens from healthy and aneusymatic (aTAA) cases. A significant variation of the fiber dispersion with respect to the unloaded state was encountered during the material traction. The corresponding microstructural and mechanical data were successfully used to fit a given anisotropic constitutive model, with satisfactory R2 values (0.97±0.11 and 0.96±0.17, for aTAA and healthy population, respectively) and fiber dispersion parameters variations between the aTAA and healthy populations (0.39±0.23 and 0.15±0.10). The method integrating the biaxial/SALS technique was validated, allowing for real-time synchronization between mechanical and microstructural analysis of anisotropic biological tissues.
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Affiliation(s)
- Emanuele Vignali
- BioCardioLab, Ospedale del Cuore, Fondazione Toscana G. Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Francesco di Bartolo
- BioCardioLab, Ospedale del Cuore, Fondazione Toscana G. Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, Ospedale del Cuore, Fondazione Toscana G. Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | | | - Giovanni Concistré
- Adult Cardiosurgery Unit, Ospedale del Cuore, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Francesca Chiaramonti
- Adult Cardiosurgery Unit, Ospedale del Cuore, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Michele Murzi
- Adult Cardiosurgery Unit, Ospedale del Cuore, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Vincenzo Positano
- BioCardioLab, Ospedale del Cuore, Fondazione Toscana G. Monasterio, Massa, Italy
| | - Luigi Landini
- Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Simona Celi
- BioCardioLab, Ospedale del Cuore, Fondazione Toscana G. Monasterio, Massa, Italy.
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Capellini K, Gasparotti E, Cella U, Costa E, Fanni BM, Groth C, Porziani S, Biancolini ME, Celi S. A novel formulation for the study of the ascending aortic fluid dynamics with in vivo data. Med Eng Phys 2020; 91:68-78. [PMID: 33008714 DOI: 10.1016/j.medengphy.2020.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/20/2020] [Accepted: 09/12/2020] [Indexed: 01/18/2023]
Abstract
Numerical simulations to evaluate thoracic aortic hemodynamics include a computational fluid dynamic (CFD) approach or fluid-structure interaction (FSI) approach. While CFD neglects the arterial deformation along the cardiac cycle by applying a rigid wall simplification, on the other side the FSI simulation requires a lot of assumptions for the material properties definition and high computational costs. The aim of this study is to investigate the feasibility of a new strategy, based on Radial Basis Functions (RBF) mesh morphing technique and transient simulations, able to introduce the patient-specific changes in aortic geometry during the cardiac cycle. Starting from medical images, aorta models at different phases of cardiac cycle were reconstructed and a transient shape deformation was obtained by proper activating incremental RBF solutions during the simulation process. The results, in terms of main hemodynamic parameters, were compared with two performed CFD simulations for the aortic model at minimum and maximum volume. Our implemented strategy copes the actual arterial variation during cardiac cycle with high accuracy, capturing the impact of geometrical variations on fluid dynamics, overcoming the complexity of a standard FSI approach.
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Affiliation(s)
- Katia Capellini
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Ubaldo Cella
- Department of Enterprise Engineering, University of Rome Tor Vergata, Rome, Italy
| | | | - Benigno Marco Fanni
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy; Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Corrado Groth
- Department of Enterprise Engineering, University of Rome Tor Vergata, Rome, Italy
| | - Stefano Porziani
- Department of Enterprise Engineering, University of Rome Tor Vergata, Rome, Italy
| | | | - Simona Celi
- BioCardioLab, Fondazione Toscana Gabriele Monasterio, Massa, Italy.
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14
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Zaccaria A, Danielli F, Gasparotti E, Fanni BM, Celi S, Pennati G, Petrini L. Left atrial appendage occlusion device: Development and validation of a finite element model. Med Eng Phys 2020; 82:104-118. [DOI: 10.1016/j.medengphy.2020.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/17/2020] [Accepted: 05/25/2020] [Indexed: 11/26/2022]
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