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Fang R, Wang Z, Wang J, Gu J, Yin G, Chen Q, Xia X, Li Z. Patient-specific pulmonary venous flow characterization and its impact on left atrial appendage thrombosis in atrial fibrillation patients. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 257:108428. [PMID: 39326361 DOI: 10.1016/j.cmpb.2024.108428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 08/30/2024] [Accepted: 09/15/2024] [Indexed: 09/28/2024]
Abstract
BACKGROUND Cardioembolic strokes are commonly occurred in non-valvular atrial fibrillation (AF) patients, with over 90% of cases originating from clot in left atrial appendage (LAA), which is believed to be greatly related with hemodynamic characters. Numerical simulation is widely accepted in the hemodynamic analysis, and patient-specific boundaries are required for realistic numerical simulations. METHOD This paper firstly proposed a method that maps personalized pulmonary venous flow (PVF) by utilizing the volume changes of the left atrium (LA) over the cardiac cycle. Then we used data from patients with AF to investigate the correlation between PVF patterns and hemodynamics within the LAA. Meanwhile, we conducted a fluid-structure interaction analysis to assess the impact of velocity- and time-related PVF parameters on LAA hemodynamic characters. RESULTS The analysis reveal that the ratio of systolic to diastolic peak velocity (VS/VD), and systolic velocity-time integral (VTI) showed a significant influence on LAA velocity in patients with atrial fibrillation, and the increases of velocity- and time-related parameters were found to be positively correlated with the blood update in the LAA. CONCLUSIONS This study established a method for mapping patient-specific PVF based on LA volume change, and evaluated the relationship between PVF parameters and thrombosis risk. The present work provides an insight from PVF characters to evaluate the risk of thrombus formation within LAA in patients with AF.
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Affiliation(s)
- Runxin Fang
- Jiangsu Institute of Metrology, Nanjing 210049, China; School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Zidun Wang
- First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, China
| | - Jiaqiu Wang
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane QLD4001, Australia; School of Engineering, London South Bank University, London, UK
| | - Jiayu Gu
- Jiangsu Institute of Metrology, Nanjing 210049, China
| | - Geman Yin
- Jiangsu Institute of Metrology, Nanjing 210049, China
| | - Qiang Chen
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xunrong Xia
- Jiangsu Institute of Metrology, Nanjing 210049, China
| | - Zhiyong Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane QLD4001, Australia; Faculty of Sports Science, Ningbo University, Ningbo, Zhejiang 315211, China.
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2
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Sardari A, Nakhaee A, Larti F, Roozitalab M. Rudimentary left atrial appendage in a patient with a history of CVA. Clin Case Rep 2024; 12:e9359. [PMID: 39247560 PMCID: PMC11377302 DOI: 10.1002/ccr3.9359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 07/25/2024] [Accepted: 07/29/2024] [Indexed: 09/10/2024] Open
Abstract
Key Clinical Message Rudimentary left atrial appendage (LAA) is an extremely rare condition with an unclear association with cerebrovascular events. This case report discusses a patient with an unexplained cerebrovascular accident (CVA), where the diagnosis of rudimentary LAA was made using transesophageal echocardiography (TEE) and subsequently confirmed by computed tomography angiography (CTA). Abstract Rudimentary left atrial appendage (LAA) is extremely rare. This report presents the case of a 50-year-old woman who experienced a cerebrovascular accident (CVA) and was found to have a rudimentary LAA. The patient had a history of diabetes mellitus (DM), hypertension, and dyslipidemia. An electrocardiogram (ECG) showed sinus rhythm, and Holter monitoring did not detect any atrial fibrillation (AF). Transesophageal echocardiography (TEE) and computed tomography angiography (CTA) were performed to identify the source of cardiac emboli, revealing a rudimentary LAA with no thrombus present.
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Affiliation(s)
- Akram Sardari
- Cardiology Department, Imam Khomeini Hospital Complex, School of Medicine Tehran University of Medical Sciences Tehran Iran
| | - Akram Nakhaee
- Cardiology Department, Imam Khomeini Hospital Complex, School of Medicine Tehran University of Medical Sciences Tehran Iran
| | - Farnoosh Larti
- Cardiology Department, Imam Khomeini Hospital Complex, School of Medicine Tehran University of Medical Sciences Tehran Iran
| | - Maryam Roozitalab
- Cardiology Department, Imam Khomeini Hospital Complex, School of Medicine Tehran University of Medical Sciences Tehran Iran
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Balzotti C, Siena P, Girfoglio M, Stabile G, Dueñas-Pamplona J, Sierra-Pallares J, Amat-Santos I, Rozza G. A reduced order model formulation for left atrium flow: an atrial fibrillation case. Biomech Model Mechanobiol 2024; 23:1411-1429. [PMID: 38753292 PMCID: PMC11341613 DOI: 10.1007/s10237-024-01847-1] [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: 09/26/2023] [Accepted: 04/07/2024] [Indexed: 08/24/2024]
Abstract
A data-driven reduced order model (ROM) based on a proper orthogonal decomposition-radial basis function (POD-RBF) approach is adopted in this paper for the analysis of blood flow dynamics in a patient-specific case of atrial fibrillation (AF). The full order model (FOM) is represented by incompressible Navier-Stokes equations, discretized with a finite volume (FV) approach. Both the Newtonian and the Casson's constitutive laws are employed. The aim is to build a computational tool able to efficiently and accurately reconstruct the patterns of relevant hemodynamics indices related to the stasis of the blood in a physical parametrization framework including the cardiac output in the Newtonian case and also the plasma viscosity and the hematocrit in the non-Newtonian one. Many FOM-ROM comparisons are shown to analyze the performance of our approach as regards errors and computational speed-up.
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Affiliation(s)
- Caterina Balzotti
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Mathlab, Trieste, Italy
| | - Pierfrancesco Siena
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Mathlab, Trieste, Italy
| | - Michele Girfoglio
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Mathlab, Trieste, Italy
| | - Giovanni Stabile
- The Biorobotics Institute, Sant'Anna School of Advanced Studies, Pisa, Italy
| | - Jorge Dueñas-Pamplona
- Departamento de Ingeniería Energética, Universidad Politécnica de Madrid, Madrid, Spain
| | - José Sierra-Pallares
- Departamento de Ingeniería Energética y Fluidomecánica, Universidad de Valladolid, Valladolid, Spain
| | - Ignacio Amat-Santos
- Departamento de Ingeniería Energética y Fluidomecánica, Universidad de Valladolid, Valladolid, Spain
- Clinical University Hospital of Valladolid, Valladolid, Spain
| | - Gianluigi Rozza
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Mathlab, Trieste, Italy.
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4
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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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5
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Zingaro A, Ahmad Z, Kholmovski E, Sakata K, Dede' L, Morris AK, Quarteroni A, Trayanova NA. A comprehensive stroke risk assessment by combining atrial computational fluid dynamics simulations and functional patient data. Sci Rep 2024; 14:9515. [PMID: 38664464 PMCID: PMC11045804 DOI: 10.1038/s41598-024-59997-2] [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: 01/26/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
Stroke, a major global health concern often rooted in cardiac dynamics, demands precise risk evaluation for targeted intervention. Current risk models, like theCHA 2 DS 2 -VASc score, often lack the granularity required for personalized predictions. In this study, we present a nuanced and thorough stroke risk assessment by integrating functional insights from cardiac magnetic resonance (CMR) with patient-specific computational fluid dynamics (CFD) simulations. Our cohort, evenly split between control and stroke groups, comprises eight patients. Utilizing CINE CMR, we compute kinematic features, revealing smaller left atrial volumes for stroke patients. The incorporation of patient-specific atrial displacement into our hemodynamic simulations unveils the influence of atrial compliance on the flow fields, emphasizing the importance of LA motion in CFD simulations and challenging the conventional rigid wall assumption in hemodynamics models. Standardizing hemodynamic features with functional metrics enhances the differentiation between stroke and control cases. While standalone assessments provide limited clarity, the synergistic fusion of CMR-derived functional data and patient-informed CFD simulations offers a personalized and mechanistic understanding, distinctly segregating stroke from control cases. Specifically, our investigation reveals a crucial clinical insight: normalizing hemodynamic features based on ejection fraction fails to differentiate between stroke and control patients. Differently, when normalized with stroke volume, a clear and clinically significant distinction emerges and this holds true for both the left atrium and its appendage, providing valuable implications for precise stroke risk assessment in clinical settings. This work introduces a novel framework for seamlessly integrating hemodynamic and functional metrics, laying the groundwork for improved predictive models, and highlighting the significance of motion-informed, personalized risk assessments.
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Affiliation(s)
- Alberto Zingaro
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA.
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy.
- ELEM Biotech S.L., Pier07, Via Laietana, 26, 08003, Barcelona, Spain.
| | - Zan Ahmad
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA
- Department of Applied Mathematics and Statistics, Johns Hopkins University, 100 Wyman Park Dr, Baltimore, MD, 21211, USA
| | - Eugene Kholmovski
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA
- Department of Radiology, University of Utah, 30 N Mario Capecchi Dr., Salt Lake City, UT, 84112, USA
| | - Kensuke Sakata
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA
| | - Luca Dede'
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Alan K Morris
- Scientific Computing and Imaging Institute, University of Utah, 72 Central Campus Dr., Salt Lake City, UT, 84112, USA
| | - Alfio Quarteroni
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
- Institute of Mathematics, École Polytechnique Fédérale de Lausanne, Station 8, Av. Piccard, 1015, Lausanne, Switzerland
| | - Natalia A Trayanova
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD, 21218, USA
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6
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Musotto G, Monteleone A, Vella D, Zuccarello B, Cannova R, Cook A, Bosi GM, Burriesci G. Fluid-structure interaction analysis of the thromboembolic risk in the left atrial appendage under atrial fibrillation: Effect of hemodynamics and morphological features. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 246:108056. [PMID: 38330768 DOI: 10.1016/j.cmpb.2024.108056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024]
Abstract
BACKGROUND Complications of atrial fibrillation (AF) include ischemic events originating within the left atrial appendage (LAA), a protrusion of the left atrium with variable morphological characteristics. The role of the patient specific morphology and pathological haemodynamics on the risk of ischemia remains unclear. METHODS This work performs a comparative assessment of the hemodynamic parameters among patient-specific LAA morphologies through fluid-structure interaction computational analyses. Three LAA models per each of the four commons patient-specific morphological families (chicken wing, cactus, windsock, and cauliflower) were analysed. Mechanical properties of the tissue were based on experimental uniaxial tests on a young pig's heart. Boundary conditions were imposed based on clinical assessments of filling and emptying volumes. Sinus rhythm and atrial fibrillation operative conditions were simulated and analysed. RESULTS For each model, the effect of morphological and functional parameters, such as the number of trabeculae and LAA stroke volume, over the hemodynamics established into the appendage was analysed. Comparison between results obtained in healthy and diseased conditions suggested the introduction of a new parameter to quantify the risk of thrombosis, here called blood stasis factor (BSF). This is defined as the LAA surface area which permanently experiences levels of shear strain rate inferior to a threshold value, set to 5 s-1 (BSF5). CONCLUSIONS This work suggests that the current morphological classification is unsuitable to evaluate the probability of thrombus formation. However, hemodynamic parameters easy to determine from clinical examinations, such as normalised stroke volume, LAA orifice flow rate and presence of extensive trabeculations can identify departures from healthy hemodynamics in AF and support a more systematic stratification of the thromboembolic risk.
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Affiliation(s)
| | | | - Danila Vella
- Bioengineering Group, Ri.MED Foundation, Palermo, Italy
| | | | - Ruggero Cannova
- Department of Engineering, University of Palermo, Palermo, Italy
| | - Andrew Cook
- UCL Institute of Cardiovascular Science& Great Ormond Street Hospital for Children, London, United Kingdom
| | - Giorgia Maria Bosi
- UCL Mechanical Engineering, University College London, London, United Kingdom
| | - Gaetano Burriesci
- Bioengineering Group, Ri.MED Foundation, Palermo, Italy; UCL Mechanical Engineering, University College London, London, United Kingdom.
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7
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Monteleone A, Di Leonardo S, Napoli E, Burriesci G. A novel mono-physics particle-based approach for the simulation of cardiovascular fluid-structure interaction problems. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 245:108034. [PMID: 38244340 DOI: 10.1016/j.cmpb.2024.108034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
BACKGROUND AND OBJECTIVE Fluid-structure interaction (FSI) is required in the study of several cardiovascular engineering problems were the mutual interaction between the pulsatile blood flow and the tissue structures is essential to establish the biomechanics of the system. Traditional FSI methods are partitioned approaches where two independent solvers, one for the fluid and one for the structure, are asynchronously coupled. This process results into high computational costs. In this work, a new FSI scheme which avoids the coupling of different solvers is presented in the framework of the truly incompressible smoothed particle hydrodynamics (ISPH) method. METHODS In the proposed FSI method, ISPH particles contribute to define both the fluid and structural domains and are solved together in a unified system. Solid particles, geometrically defined at the beginning of the simulation, are linked through spring bounds with elastic constant providing the material Young's modulus. At each iteration, internal elastic forces are calculated to restore the springs resting length. These forces are added in the predictor step of the fractional-step procedure used to solve the momentum and continuity equations for incompressible flows of all particles. RESULTS The method was validated with a benchmark test case consisting of a flexible beam immersed in a channel. Results showed good agreement with the system coupling approach of a well-established commercial software, ANSYS®, both in terms of fluid-dynamics and beam deformation. The approach was then applied to model a complex cardiovascular problem, consisting in the aortic valve operating function. The valve dynamics during opening and closing phases were compared qualitatively with literature results, demonstrating good consistency. CONCLUSIONS The method is computationally more efficient than traditional FSI strategies, and overcomes some of their main drawbacks, such as the impossibility of simulating the correct valve coaptation during the closing phase. Thanks to the incompressibility scheme, the proposed FSI method is appropriate to model biological soft tissues. The simplicity and flexibility of the approach also makes it suitable to be expanded for the modelling of thromboembolic phenomena.
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Affiliation(s)
| | | | - Enrico Napoli
- Engineering Department, University of Palermo, Italy
| | - Gaetano Burriesci
- Ri.MED Foundation, Palermo, Italy; UCL Mechanical Engineering, University College London, UK.
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8
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Di Leonardo S, Monteleone A, Caruso P, Meecham-Garcia H, Pitarresi G, Burriesci G. Effect of the apron in the mechanical characterisation of hyperelastic materials by means of biaxial testing: A new method to improve accuracy. J Mech Behav Biomed Mater 2024; 150:106291. [PMID: 38103333 DOI: 10.1016/j.jmbbm.2023.106291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
Biological soft tissues and polymers used in biomedical applications (e.g. in the cardiovascular area) are hyperelastic incompressible materials that commonly operate under multi-axial large deformation fields. Their characterisation requires biaxial tensile testing. Due to the typically small sample size, the gripping of the specimens commonly relies on rakes or sutures, where the specimen is punctured at the edges of the gauge area. This approach necessitates of an apron, excess of material around the gauge region. This work analyses the apron influence on the estimated mechanical response of biaxial tests performed by using a rakes gripping system, with the aim of verifying the test accuracy and propose improved solutions. In order to isolate the effect of the apron, avoiding the influence of anisotropy and inhomogeneity typical of most soft tissues, homogeneous and isotropic hyperplastic samples made from a uniform sheet of casted silicone were tested. The stress-strain response of specimens with different apron sizes/shapes was measured experimentally by means of biaxial testing and digital image correlation. Tests were replicated numerically, to interpret the experimental findings. The apron surrounding the gauge area acts as an additional annular constraint which stiffens the system, resulting in a significant overestimate in the stress values. This error can be avoided by introducing specific cuts in the apron. The study quantifies, for the first time, the correlation between the apron size/shape and the experimental stress overestimation, proposing a research protocol which, although identified on homogeneous hyperelastic materials, can be useful in providing more accurate characterisation of both, synthetic polymers and soft tissues.
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Affiliation(s)
| | | | - Patrizia Caruso
- Ri.MED Foundation, Palermo, Italy; Engineering Department, University of Palermo, Italy
| | | | | | - Gaetano Burriesci
- Ri.MED Foundation, Palermo, Italy; UCL Mechanical Engineering, University College London, UK.
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9
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Zingaro A, Ahmad Z, Kholmovski E, Sakata K, Dede’ L, Morris AK, Quarteroni A, Trayanova NA. A comprehensive stroke risk assessment by combining atrial computational fluid dynamics simulations and functional patient data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.11.575156. [PMID: 38293150 PMCID: PMC10827064 DOI: 10.1101/2024.01.11.575156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Stroke, a major global health concern often rooted in cardiac dynamics, demands precise risk evaluation for targeted intervention. Current risk models, like the CHA2DS2-VASc score, often lack the granularity required for personalized predictions. In this study, we present a nuanced and thorough stroke risk assessment by integrating functional insights from cardiac magnetic resonance (CMR) with patient-specific computational fluid dynamics (CFD) simulations. Our cohort, evenly split between control and stroke groups, comprises eight patients. Utilizing CINE CMR, we compute kinematic features, revealing smaller left atrial volumes for stroke patients. The incorporation of patient-specific atrial displacement into our hemodynamic simulations unveils the influence of atrial compliance on the flow fields, emphasizing the importance of LA motion in CFD simulations and challenging the conventional rigid wall assumption in hemodynamics models. Standardizing hemodynamic features with functional metrics enhances the differentiation between stroke and control cases. While standalone assessments provide limited clarity, the synergistic fusion of CMR-derived functional data and patient-informed CFD simulations offers a personalized and mechanistic understanding, distinctly segregating stroke from control cases. Specifically, our investigation reveals a crucial clinical insight: normalizing hemodynamic features based on ejection fraction fails to differentiate between stroke and control patients. Differently, when normalized with stroke volume, a clear and clinically significant distinction emerges and this holds true for both the left atrium and its appendage, providing valuable implications for precise stroke risk assessment in clinical settings. This work introduces a novel framework for seamlessly integrating hemodynamic and functional metrics, laying the groundwork for improved predictive models, and highlighting the significance of motion-informed, personalized risk assessments.
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Affiliation(s)
- Alberto Zingaro
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., 21218, Baltimore, MD, USA
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
- ELEM Biotech S.L., Pier07, Via Laietana, 26, 08003, Barcelona, Spain
| | - Zan Ahmad
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., 21218, Baltimore, MD, USA
- Department of Applied Mathematics and Statistics, Johns Hopkins University, 100 Wyman Park Dr, 21211, Baltimore, MD, USA
| | - Eugene Kholmovski
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., 21218, Baltimore, MD, USA
- Department of Radiology, University of Utah, 30 N Mario Capecchi Dr., 84112, Salt Lake City, UT, USA
| | - Kensuke Sakata
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., 21218, Baltimore, MD, USA
| | - Luca Dede’
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Alan K. Morris
- Scientific Computing and Imaging Institute, University of Utah, 72 Central Campus Dr., 84112, Salt Lake City, UT, USA
| | - Alfio Quarteroni
- MOX, Laboratory of Modeling and Scientific Computing, Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milano, Italy
- Institute of Mathematics, École Polytechnique Fédérale de Lausanne, Station 8, Av. Piccard, CH-1015 Lausanne, Switzerland (Professor Emeritus)
| | - Natalia A. Trayanova
- ADVANCE, Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, 3400 N. Charles St., 21218, Baltimore, MD, USA
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Bäck S, Skoda I, Lantz J, Henriksson L, Karlsson LO, Persson A, Carlhäll CJ, Ebbers T. Elevated atrial blood stasis in paroxysmal atrial fibrillation during sinus rhythm: a patient-specific computational fluid dynamics study. Front Cardiovasc Med 2023; 10:1219021. [PMID: 37649669 PMCID: PMC10463733 DOI: 10.3389/fcvm.2023.1219021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/31/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction Atrial fibrillation (AF) is associated with an increased risk of stroke, often caused by thrombi that form in the left atrium (LA), and especially in the left atrial appendage (LAA). The underlying mechanism is not fully understood but is thought to be related to stagnant blood flow, which might be present despite sinus rhythm. However, measuring blood flow and stasis in the LAA is challenging due to its small size and low velocities. We aimed to compare the blood flow and stasis in the left atrium of paroxysmal AF patients with controls using computational fluid dynamics (CFD) simulations. Methods The CFD simulations were based on time-resolved computed tomography including the patient-specific cardiac motion. The pipeline allowed for analysis of 21 patients with paroxysmal AF and 8 controls. Stasis was estimated by computing the blood residence time. Results and Discussion Residence time was elevated in the AF group (p < 0.001). Linear regression analysis revealed that stasis was strongest associated with LA ejection ratio (p < 0.001, R2 = 0.68) and the ratio of LA volume and left ventricular stroke volume (p < 0.001, R2 = 0.81). Stroke risk due to LA thrombi could already be elevated in AF patients during sinus rhythm. In the future, patient specific CFD simulations may add to the assessment of this risk and support diagnosis and treatment.
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Affiliation(s)
- Sophia Bäck
- Unit of Cardiovascular Sciences, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Iulia Skoda
- Department of Cardiology in Linköping, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Jonas Lantz
- Unit of Cardiovascular Sciences, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Lilian Henriksson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Department of Radiology, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Lars O. Karlsson
- Department of Cardiology in Linköping, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Anders Persson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Department of Radiology, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Carl-Johan Carlhäll
- Unit of Cardiovascular Sciences, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Department of Clinical Physiology in Linköping, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Tino Ebbers
- Unit of Cardiovascular Sciences, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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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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