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Darwish A, Papolla C, Rieu R, Kadem L. An Anatomically Shaped Mitral Valve for Hemodynamic Testing. Cardiovasc Eng Technol 2024:10.1007/s13239-024-00714-5. [PMID: 38228812 DOI: 10.1007/s13239-024-00714-5] [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: 04/24/2023] [Accepted: 01/02/2024] [Indexed: 01/18/2024]
Abstract
In vitro modeling of the left heart relies on accurately replicating the physiological conditions of the native heart. The targeted physiological conditions include the complex fluid dynamics coming along with the opening and closing of the aortic and mitral valves. As the mitral valve possess a highly sophisticated apparatus, thence, accurately modeling it remained a missing piece in the perfect heart duplicator puzzle. In this study, we explore using a hydrogel-based mitral valve that offers a full representation of the mitral valve apparatus. The valve is tested using a custom-made mock circulatory loop to replicate the left heart. The flow analysis includes performing particle image velocimetry measurements in both left atrium and ventricle. The results showed the ability of the new mitral valve to replicate the real interventricular and atrial flow patterns during the whole cardiac cycle. Moreover, the investigated valve has a ventricular vortex formation time of 5.2, while the peak e- and a-wave ventricular velocities was 0.9 m/s and 0.4 m/s respectively.
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Affiliation(s)
- Ahmed Darwish
- Laboratory of Cardiovascular Fluid Dynamics, Concordia University, Montreal, QC, H3G 1M8, Canada.
- Mechanical Power Engineering Department, Assiut University, Assiut, 71515, Egypt.
| | - Chloé Papolla
- Laboratory of Cardiovascular Fluid Dynamics, Concordia University, Montreal, QC, H3G 1M8, Canada
- Aix-Marseille University, LBA UMR T24, Marseille, France
| | - Régis Rieu
- Aix-Marseille University, LBA UMR T24, Marseille, France
| | - Lyes Kadem
- Laboratory of Cardiovascular Fluid Dynamics, Concordia University, Montreal, QC, H3G 1M8, Canada
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Vellguth K, Barbieri F, Reinthaler M, Kasner M, Landmesser U, Kuehne T, Hennemuth A, Walczak L, Goubergrits L. Effect of transcatheter edge-to-edge repair device position on diastolic hemodynamic parameters: An echocardiography-based simulation study. Front Cardiovasc Med 2022; 9:915074. [PMID: 36093164 PMCID: PMC9449143 DOI: 10.3389/fcvm.2022.915074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundTranscatheter edge-to-edge repair (TEER) has developed from innovative technology to an established treatment strategy of mitral regurgitation (MR). The risk of iatrogenic mitral stenosis after TEER is, however, a critical factor in the conflict of interest between maximal reduction of MR and minimal impairment of left ventricular filling. We aim to investigate systematically the impact of device position on the post treatment hemodynamic outcome by involving the patient-specific segmentation of the diseased mitral valve.Materials and methodsTransesophageal echocardiographic image data of ten patients with severe MR (age: 57 ± 8 years, 20% female) were segmented and virtually treated with TEER at three positions by using a position based dynamics approach. Pre- and post-interventional patient geometries were preprocessed for computational fluid dynamics (CFD) and simulated at peak-diastole with patient-specific blood flow boundary conditions. Simulations were performed with boundary conditions mimicking rest and stress. The simulation results were compared with clinical data acquired for a cohort of 21 symptomatic MR patients (age: 79 ± 6 years, 43% female) treated with TEER.ResultsVirtual TEER reduces the mitral valve area (MVA) from 7.5 ± 1.6 to 2.6 ± 0.6 cm2. Central device positioning resulted in a 14% smaller MVA than eccentric device positions. Furthermore, residual MVA is better predictable for central than for eccentric device positions (R2 = 0.81 vs. R2 = 0.49). The MVA reduction led to significantly higher maximal diastolic velocities (pre: 0.9 ± 0.2 m/s, post: 2.0 ± 0.5 m/s) and pressure gradients (pre: 1.5 ± 0.6 mmHg, post: 16.3 ± 9 mmHg) in spite of a mean flow rate reduction by 23% due to reduced MR after the treatment. On average, velocities were 12% and pressure gradients were 25% higher with devices in central compared to lateral or medial positions.ConclusionVirtual TEER treatment combined with CFD is a promising tool for predicting individual morphometric and hemodynamic outcomes. Such a tool can potentially be used to support clinical decision making, procedure planning, and risk estimation to prevent post-procedural iatrogenic mitral stenosis.
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Affiliation(s)
- Katharina Vellguth
- Institute of Computer-Assisted Cardiovascular Medicine, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- *Correspondence: Katharina Vellguth
| | - Fabian Barbieri
- Department of Cardiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Markus Reinthaler
- Department of Cardiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Institute of Active Polymers and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Hereon, Teltow, Germany
| | - Mario Kasner
- Department of Cardiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ulf Landmesser
- Department of Cardiology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Berlin, Germany
- Berlin Institute of Health at Charité—Universitätsmedizin Berlin, Berlin, Germany
| | - Titus Kuehne
- Institute of Computer-Assisted Cardiovascular Medicine, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Berlin, Germany
- Deutsches Herzzentrum der Charité—Medical Heart Center of Charité and German Heart Institute Berlin, Berlin, Germany
| | - Anja Hennemuth
- Institute of Computer-Assisted Cardiovascular Medicine, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Fraunhofer MEVIS, Bremen, Germany
| | - Lars Walczak
- Institute of Computer-Assisted Cardiovascular Medicine, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Fraunhofer MEVIS, Bremen, Germany
| | - Leonid Goubergrits
- Institute of Computer-Assisted Cardiovascular Medicine, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Einstein Center Digital Future, Berlin, Germany
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Obermeier L, Vellguth K, Schlief A, Tautz L, Bruening J, Knosalla C, Kuehne T, Solowjowa N, Goubergrits L. CT-Based Simulation of Left Ventricular Hemodynamics: A Pilot Study in Mitral Regurgitation and Left Ventricle Aneurysm Patients. Front Cardiovasc Med 2022; 9:828556. [PMID: 35391837 PMCID: PMC8980692 DOI: 10.3389/fcvm.2022.828556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/03/2022] [Indexed: 12/30/2022] Open
Abstract
BackgroundCardiac CT (CCT) is well suited for a detailed analysis of heart structures due to its high spatial resolution, but in contrast to MRI and echocardiography, CCT does not allow an assessment of intracardiac flow. Computational fluid dynamics (CFD) can complement this shortcoming. It enables the computation of hemodynamics at a high spatio-temporal resolution based on medical images. The aim of this proposed study is to establish a CCT-based CFD methodology for the analysis of left ventricle (LV) hemodynamics and to assess the usability of the computational framework for clinical practice.Materials and MethodsThe methodology is demonstrated by means of four cases selected from a cohort of 125 multiphase CCT examinations of heart failure patients. These cases represent subcohorts of patients with and without LV aneurysm and with severe and no mitral regurgitation (MR). All selected LVs are dilated and characterized by a reduced ejection fraction (EF). End-diastolic and end-systolic image data was used to reconstruct LV geometries with 2D valves as well as the ventricular movement. The intraventricular hemodynamics were computed with a prescribed-motion CFD approach and evaluated in terms of large-scale flow patterns, energetic behavior, and intraventricular washout.ResultsIn the MR patients, a disrupted E-wave jet, a fragmentary diastolic vortex formation and an increased specific energy dissipation in systole are observed. In all cases, regions with an impaired washout are visible. The results furthermore indicate that considering several cycles might provide a more detailed view of the washout process. The pre-processing times and computational expenses are in reach of clinical feasibility.ConclusionThe proposed CCT-based CFD method allows to compute patient-specific intraventricular hemodynamics and thus complements the informative value of CCT. The method can be applied to any CCT data of common quality and represents a fair balance between model accuracy and overall expenses. With further model enhancements, the computational framework has the potential to be embedded in clinical routine workflows, to support clinical decision making and treatment planning.
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Affiliation(s)
- Lukas Obermeier
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
- *Correspondence: Lukas Obermeier
| | - Katharina Vellguth
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Adriano Schlief
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lennart Tautz
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Fraunhofer Institute for Digital Medicine MEVIS, Bremen, Germany
| | - Jan Bruening
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Christoph Knosalla
- Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Titus Kuehne
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
- Department of Congenital Heart Disease, German Heart Center Berlin, Berlin, Germany
| | - Natalia Solowjowa
- Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany
| | - Leonid Goubergrits
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Einstein Center Digital Future, Berlin, Germany
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Alterations in Intracardiac Flow Patterns Affect Mitral Leaflets Dynamics in a Model of Ischemic Mitral Regurgitation. Cardiovasc Eng Technol 2021; 12:640-650. [PMID: 34467514 DOI: 10.1007/s13239-021-00567-2] [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: 07/22/2020] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE This study was to evaluate the effects of ischemic mitral regurgitation (IMR) on vortex formation and leaflet dynamics using an established porcine infarct model of IMR. METHODS Using direct coronary ligation, five animals were subjected to a posterolateral myocardial infarction (MI) followed by an MRI at 12-weeks post MI. MR imaging consisted of 4D time-resolved left ventricular (LV) flow, full coverage 2D LV cine, and high resolution 2D cine of mitral valve dynamics. Five additional naïve animals underwent identical imaging protocols to serve as controls. Image analysis was performed to obtain mitral transvalvular flows as well as LV volumes throughout the cardiac cycle. In addition, anterior to posterior mid-leaflet tip distances were measured throughout the cardiac cycle for determination of temporal leaflet dynamics. RESULTS It was found IMR caused asymmetric vortex ring formation with the anterior vortex having a lower vorticity relative to its posterior counterpart. In contrast, normal ventricles create symmetric and tightly curled vortices in the basal chamber just underneath the mitral leaflets which conserve kinetic energy and aid in effective ejection. IMR animals were also evaluated for leaflet separation and were found to have a greater leaflet opening and achieved peak vorticity and peak leaflet opening later than control animals. CONCLUSION In conclusion, this study shows the effects that altered vortex formation, due to IMR, can have on ventricular filling and leaflet dynamics. These findings have important implications for understanding blood flow through the dilated heart and how ring annuloplasty and volume reduction interventions may influence mitral valve dynamics.
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Lantz J, Bäck S, Carlhäll CJ, Bolger A, Persson A, Karlsson M, Ebbers T. Impact of prosthetic mitral valve orientation on the ventricular flow field: Comparison using patient-specific computational fluid dynamics. J Biomech 2020; 116:110209. [PMID: 33422725 DOI: 10.1016/j.jbiomech.2020.110209] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 11/29/2022]
Abstract
Significant mitral valve regurgitation creates progressive adverse remodeling of the left ventricle (LV). Replacement of the failing valve with a prosthesis generally improves patient outcomes but leaves the patient with non-physiological intracardiac flow patterns that might contribute to their future risk of thrombus formation and embolism. It has been suggested that the angular orientation of the implanted valve might modify the postoperative distortion of the intraventricular flow field. In this study, we investigated the effect of prosthetic valve orientation on LV flow patterns by using heart geometry from a patient with LV dysfunction and a competent native mitral valve to calculate intracardiac flow fields with computational fluid dynamics (CFD). Results were validated using in vivo 4D Flow MRI. The computed flow fields were compared to calculations following virtual implantation of a mechanical heart valve oriented in four different angles to assess the effect of leaflet position. Flow patterns were visualized in long- and short-axes and quantified with flow component analysis. In comparison to a native valve, valve implantation increased the proportion of the mitral inflow remaining in the basal region and further increased the residual volume in the apical area. Only slight changes due to valve orientation were observed. Using our numerical framework, we demonstrated quantitative changes in left ventricular blood flow due to prosthetic mitral replacement. This framework may be used to improve design of prosthetic heart valves and implantation procedures to minimize the potential for apical flow stasis, and potentially assist personalized treatment planning.
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Affiliation(s)
- Jonas Lantz
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Sophia Bäck
- Division of Cardiovascular Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Carl-Johan Carlhäll
- 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
| | - Ann Bolger
- Department of Clinical Physiology in Linköping, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Department of Medicine, University of California, San Francisco, United States
| | - Anders Persson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden; Division of Radiology, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Matts Karlsson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden; Division of Applied Thermodynamics and Fluid Mechanics, Department of Management and Engineering, Linköping University, Sweden
| | - Tino Ebbers
- Division of Cardiovascular Medicine, 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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Samaee M, Nelsen NH, Gaddam MG, Santhanakrishnan A. Diastolic Vortex Alterations With Reducing Left Ventricular Volume: An In Vitro Study. J Biomech Eng 2020; 142:1084897. [DOI: 10.1115/1.4047663] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Indexed: 12/15/2022]
Abstract
Abstract
Despite the large number of studies of intraventricular filling dynamics for potential clinical applications, little is known as to how the diastolic vortex ring properties are altered with reduction in internal volume of the cardiac left ventricle (LV). The latter is of particular importance in LV diastolic dysfunction (LVDD) and in congenital diseases such as hypertrophic cardiomyopathy (HCM), where LV hypertrophy (LVH) can reduce LV internal volume. We hypothesized that peak circulation and the rate of decay of circulation of the diastolic vortex would be altered with reducing end diastolic volume (EDV) due to increasing confinement. We tested this hypothesis on physical models of normal LV and HCM geometries, under identical prescribed inflow profiles and for multiple EDVs, using time-resolved particle image velocimetry (TR-PIV) measurements on a left heart simulator. Formation and pinch-off of the vortex ring were nearly unaffected with changes to geometry and EDV. Pinch-off occurred before the end of early filling (E-wave) in all test conditions. Peak circulation of the vortex core near the LV outflow tract (LVOT) increased with lowering EDV and was lowest for the HCM model. The rate of decay of normalized circulation in dimensionless formation time (T*) increased with decreasing EDV. When using a modified version of T* that included average LV cross-sectional area and EDV, normalized circulation of all tested EDVs collapsed closely in the normal LV model (10% maximum difference between EDVs). Collectively, our results show that LV shape and internal volume play a critical role in diastolic vortex ring dynamics.
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Affiliation(s)
- Milad Samaee
- School of Mechanical and Aerospace Engineering, Oklahoma State University, 201 General Academic Building, Stillwater, OK 74078
| | - Nicholas H. Nelsen
- School of Mechanical and Aerospace Engineering, Oklahoma State University, 201 General Academic Building, Stillwater, OK 74078
| | - Manikantam G. Gaddam
- School of Mechanical and Aerospace Engineering, Oklahoma State University, 201 General Academic Building, Stillwater, OK 74078
| | - Arvind Santhanakrishnan
- School of Mechanical and Aerospace Engineering, Oklahoma State University, 201 General Academic Building, Stillwater, OK 74078
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Tan SG, Hon JKF, Nguyen YN, Kim S, Leo HL. An in vitro investigation into the hemodynamic effects of orifice geometry and position on left ventricular vortex formation and turbulence intensity. Artif Organs 2020; 44:e520-e531. [DOI: 10.1111/aor.13781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 12/26/2022]
Affiliation(s)
- Sean Guo‐Dong Tan
- Department of Biomedical Engineering National University of Singapore Singapore Singapore
| | - Jimmy Kim Fatt Hon
- Department of Surgery Yong Loo Lin School of MedicineNational University of Singapore Singapore Singapore
| | - Yen Ngoc Nguyen
- Department of Biomedical Engineering National University of Singapore Singapore Singapore
| | - Sangho Kim
- Department of Biomedical Engineering National University of Singapore Singapore Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering National University of Singapore Singapore Singapore
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The Effect of Dobutamine Stress Testing on Vortex Formation Time in Patients Evaluated for Ischemia. J Cardiovasc Transl Res 2020; 14:735-743. [DOI: 10.1007/s12265-020-09998-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023]
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Rutkowski DR, Barton GP, François CJ, Aggarwal N, Roldán-Alzate A. Sex Differences in Cardiac Flow Dynamics of Healthy Volunteers. Radiol Cardiothorac Imaging 2020; 2. [PMID: 32666051 DOI: 10.1148/ryct.2020190058] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Purpose The purpose of this study was to further understand the relationship between cardiac function and flow, on the basis of sex, by quantifying cardiac flow characteristics and relating them to cardiac muscle performance in young adults. Materials and Methods In this cross-sectional study, cardiac four-dimensional flow (4D flow) magnetic resonance imaging (MRI) and two-dimensional cine MRI were performed on 20 male and 19 female volunteers aged 20-35. Velocity-based metrics of flow, kinetic energy, vorticity, and efficiency indices were quantified, as well as cardiac strain metrics. Results* Peak systolic blood kinetic energy (male: 4.76 ± 2.66 mJ; female: 3.36 ± 1.43 mJ; p=0.047) was significantly higher in the male left ventricle (LV) than in the female LV. Peak systolic vorticity index (male: 0.008 ± 0.005 rad-m2/ml-s; female: 0.014 ± 0.007 rad-m2/ml-s; p=0.007), peak diastolic vorticity index (male: 0.007 ± 0.006 rad-m2/ml-s; female: 0.014 ± 0.010 rad-m2/ml-s; p=0.015), and cycle-average vorticity (male: 0.006 ± 0.001 rad-m2/ml-s; female: 0.011 ± 0.002 rad/s; p=0.001) were all significantly higher in the LV of women than they were in the LV of men. Radial, circumferential, and long-axis strain metrics were significantly higher in the female LV than in the male LV (p<0.05). Circumferential systolic and diastolic strain rates displayed moderate correlation to peak systolic (r=-0.38, p=0.022) and diastolic vorticity (r=0.40, p=0.015) values, respectively. *Results are reported as mean ± standard deviation. Conclusion Left ventricular vorticity metrics were observed to be higher in women than in men and displayed moderate correlation to cardiac strain metrics. The methods and results of this study may be used to further understand the sex-based cardiac efficiency relationship between cardiac function and flow.
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Affiliation(s)
- David R Rutkowski
- Departments of Mechanical Engineering (D.R.R., A.R.A.), Radiology (D.R.R., G.P.B., C.J.F., A.R.A.), Medical Physics (G.P.B.), Cardiovascular Medicine (N.A.), and Biomedical Engineering (A.R.A.), University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705
| | - Gregory P Barton
- Departments of Mechanical Engineering (D.R.R., A.R.A.), Radiology (D.R.R., G.P.B., C.J.F., A.R.A.), Medical Physics (G.P.B.), Cardiovascular Medicine (N.A.), and Biomedical Engineering (A.R.A.), University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705
| | - Christopher J François
- Departments of Mechanical Engineering (D.R.R., A.R.A.), Radiology (D.R.R., G.P.B., C.J.F., A.R.A.), Medical Physics (G.P.B.), Cardiovascular Medicine (N.A.), and Biomedical Engineering (A.R.A.), University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705
| | - Niti Aggarwal
- Departments of Mechanical Engineering (D.R.R., A.R.A.), Radiology (D.R.R., G.P.B., C.J.F., A.R.A.), Medical Physics (G.P.B.), Cardiovascular Medicine (N.A.), and Biomedical Engineering (A.R.A.), University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705
| | - Alejandro Roldán-Alzate
- Departments of Mechanical Engineering (D.R.R., A.R.A.), Radiology (D.R.R., G.P.B., C.J.F., A.R.A.), Medical Physics (G.P.B.), Cardiovascular Medicine (N.A.), and Biomedical Engineering (A.R.A.), University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705
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Danis U, Rasooli R, Chen CY, Dur O, Sitti M, Pekkan K. Thrust and Hydrodynamic Efficiency of the Bundled Flagella. MICROMACHINES 2019; 10:mi10070449. [PMID: 31277385 PMCID: PMC6680724 DOI: 10.3390/mi10070449] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/23/2019] [Accepted: 05/26/2019] [Indexed: 01/09/2023]
Abstract
The motility mechanism of prokaryotic organisms has inspired many untethered microswimmers that could potentially perform minimally invasive medical procedures in stagnant fluid regions inside the human body. Some of these microswimmers are inspired by bacteria with single or multiple helical flagella to propel efficiently and fast. For multiple flagella configurations, the direct measurement of thrust and hydrodynamic propulsion efficiency has been challenging due to the ambiguous mechanical coupling between the flow field and mechanical power input. To address this challenge and to compare alternative micropropulsion designs, a methodology based on volumetric velocity field acquisition is developed to acquire the key propulsive performance parameters from scaled-up swimmer prototypes. A digital particle image velocimetry (PIV) analysis protocol was implemented and experiments were conducted with the aid of computational fluid dynamics (CFD). First, this methodology was validated using a rotating single-flagellum similitude model. In addition to the standard PIV error assessment, validation studies included 2D vs. 3D PIV, axial vs. lateral PIV and simultaneously acquired direct thrust force measurement comparisons. Compatible with typical micropropulsion flow regimes, experiments were conducted both for very low and higher Reynolds (Re) number regimes (up to a Re number = 0.01) than that are reported in the literature. Finally, multiple flagella bundling configurations at 0°, 90° and 180° helical phase-shift angles were studied using scaled-up multiple concentric flagella thrust elements. Thrust generation was found to be maximal for the in-phase (0°) bundling configuration but with ~50% lower hydrodynamic efficiency than the single flagellum. The proposed measurement protocol and static thrust test-bench can be used for bio-inspired microscale propulsion methods, where direct thrust and efficiency measurement are required.
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Affiliation(s)
- Umit Danis
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Reza Rasooli
- Department of Mechanical Engineering, Koc University, Istanbul 34450, Turkey
| | - Chia-Yuan Chen
- Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Onur Dur
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Metin Sitti
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Mechanical Engineering, Koc University, Istanbul 34450, Turkey
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart 70569, Germany
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Istanbul 34450, Turkey.
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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Effects of left atrium on intraventricular flow in numerical simulations. Comput Biol Med 2019; 106:46-53. [DOI: 10.1016/j.compbiomed.2019.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 01/07/2023]
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12
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Rutkowski DR, Barton G, François CJ, Bartlett HL, Anagnostopoulos PV, Roldán-Alzate A. Analysis of cavopulmonary and cardiac flow characteristics in fontan Patients: Comparison with healthy volunteers. J Magn Reson Imaging 2019; 49:1786-1799. [PMID: 30635978 DOI: 10.1002/jmri.26583] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/06/2018] [Accepted: 11/06/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Characterizing the flow of the Fontan circuit, and correlating flow characteristics with the development of complications, is an important clinical challenge. Past work has analyzed the flow characteristics of Fontan circulation on a component-by-component basis. 4D flow MRI with radial projections allows for large volumetric coverage, and therefore can be used to analyze the flow through many codependent cardiovascular components in a single imaging session. PURPOSE To describe flow characteristics across the entire Fontan circuit and to compare these with the flow characteristics in healthy volunteers. STUDY TYPE Prospective. SUBJECTS Eleven single ventricle patients with a Fontan connection and 15 healthy controls. SEQUENCE Phase contrast with vastly undersampled isotropic projection reconstruction (PC-VIPR) at a field strength of 3 T. ASSESSMENT Cavopulmonary and ventricular flow distributions, blood flow kinetic energy, vorticities, efficiency indices, and other flow parameters were analyzed using Ensight and MatLab. STATISTICAL TESTS The results were compared across Fontan subjects, between respiratory phases, and between Fontan subjects and healthy volunteers using a Student's t-test for unequal sample sizes and linear regression. RESULTS Cava-specific pulmonary flow distributions of Fontan patients varied significantly between respiratory phases (P < 0.05). Ventricular kinetic energy (KE) was significantly higher in Fontan patients than it was in healthy controls, leading to a lower cardiac efficiency metric in the Fontan group. A significant diastolic KE time-shift was also observed in the Fontan patient group. Peak diastolic KE was significantly higher in the single ventricle of patients with right ventricle morphology than it was in left ventricle morphology patients. DATA CONCLUSION Radial 4D flow MRI can be used for comprehensive analysis of single ventricle Fontan flow characteristics. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019.
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Affiliation(s)
- David R Rutkowski
- Mechanical Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Gregory Barton
- Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | | | - Heather L Bartlett
- Pediatrics and Medicine, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | | | - Alejandro Roldán-Alzate
- Mechanical Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Radiology, University of Wisconsin - Madison, Madison, Wisconsin, USA.,Biomedical Engineering, University of Wisconsin - Madison, Madison, Wisconsin, USA
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13
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Sotelo J, Urbina J, Valverde I, Mura J, Tejos C, Irarrazaval P, Andia ME, Hurtado DE, Uribe S. Three-dimensional quantification of vorticity and helicity from 3D cine PC-MRI using finite-element interpolations. Magn Reson Med 2017; 79:541-553. [DOI: 10.1002/mrm.26687] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/01/2017] [Accepted: 03/05/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Julio Sotelo
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Electrical Engineering; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Structural and Geotechnical Engineering; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Jesús Urbina
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Radiology; School of Medicine, Pontificia Universidad Católica de Chile; Santiago Chile
| | - Israel Valverde
- Pediatric Cardiology Unit; Hospital Virgen del Rocio; Sevilla Spain
- Cardiovascular Pathology Unit; Institute of Biomedicine of Seville (IBIS), Hospital Virgen del Rocio; Sevilla Spain
| | - Joaquín Mura
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
| | - Cristián Tejos
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Electrical Engineering; Pontificia Universidad Católica de Chile; Santiago Chile
- Institute for Biological and Medical Engineering; Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile; Santaigo Chile
| | - Pablo Irarrazaval
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Electrical Engineering; Pontificia Universidad Católica de Chile; Santiago Chile
- Institute for Biological and Medical Engineering; Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile; Santaigo Chile
| | - Marcelo E. Andia
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Radiology; School of Medicine, Pontificia Universidad Católica de Chile; Santiago Chile
- Institute for Biological and Medical Engineering; Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile; Santaigo Chile
| | - Daniel E. Hurtado
- Department of Structural and Geotechnical Engineering; Pontificia Universidad Católica de Chile; Santiago Chile
- Institute for Biological and Medical Engineering; Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile; Santaigo Chile
| | - Sergio Uribe
- Biomedical Imaging Center; Pontificia Universidad Católica de Chile; Santiago Chile
- Department of Radiology; School of Medicine, Pontificia Universidad Católica de Chile; Santiago Chile
- Institute for Biological and Medical Engineering; Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile; Santaigo Chile
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14
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Wong KKL, Wang D, Ko JKL, Mazumdar J, Le TT, Ghista D. Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures. Biomed Eng Online 2017; 16:35. [PMID: 28327144 PMCID: PMC5359907 DOI: 10.1186/s12938-017-0326-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/13/2017] [Indexed: 11/10/2022] Open
Abstract
Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.
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Affiliation(s)
- Kelvin K. L. Wong
- School of Medicine, University of Western Sydney, Campbelltown, Sydney, NSW 2560 Australia
- School of Medicine, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 Australia
| | - Defeng Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jacky K. L. Ko
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jagannath Mazumdar
- Centre for Biomedical Engineering and School of Electrical and Electronics Engineering, University of Adelaide, Adelaide, SA 5005 Australia
| | - Thu-Thao Le
- National Heart Centre, Mistri Wing, 17 Third Hospital Avenue, Singapore, 168752 Singapore
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15
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Aortic Regurgitation Generates a Kinematic Obstruction Which Hinders Left Ventricular Filling. Ann Biomed Eng 2017; 45:1305-1314. [PMID: 28091966 DOI: 10.1007/s10439-017-1790-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
Abstract
An incompetent aortic valve (AV) results in aortic regurgitation (AR), where retrograde flow of blood into the left ventricle (LV) is observed. In this work, we parametrically characterized the detailed changes in intra-ventricular flow during diastole as a result of AR in a physiological in vitro left-heart simulator (LHS). The loss of energy within the LV as the level of AR increased was also assessed. The validated LHS consisted of an optically-clear, flexible wall LV and a modular AV holder. Two-component, planar, digital particle image velocimetry was used to visualize and quantify intra-ventricular flow. A large coherent vortical structure which engulfed the whole LV was observed under control conditions. In the cases with AR, the regurgitant jet was observed to generate a "kinematic obstruction" between the mitral valve and the LV apex, preventing the trans-mitral jet from generating a coherent vortical structure. The regurgitant jet was also observed to impinge on the inferolateral wall of the LV. Energy dissipation rate (EDR) for no, trace, mild, and moderate AR were found to be 1.15, 2.26, 3.56, and 5.99 W/m3, respectively. This study has, for the first time, performed an in vitro characterization of intra-ventricular flow in the presence of AR. Mechanistically, the formation of a "kinematic obstruction" appears to be the cause of the increased EDR (a metric quantifiable in vivo) during AR. EDR increases non-linearly with AR fraction and could potentially be used as a metric to grade severity of AR and develop clinical interventional timing strategies for patients.
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16
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Okafor IU, Santhanakrishnan A, Raghav VS, Yoganathan AP. Role of Mitral Annulus Diastolic Geometry on Intraventricular Filling Dynamics. J Biomech Eng 2016; 137:121007. [PMID: 26502376 DOI: 10.1115/1.4031838] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Indexed: 11/08/2022]
Abstract
The mitral valve (MV) is a bileaflet valve positioned between the left atrium and ventricle of the heart. The annulus of the MV has been observed to undergo geometric changes during the cardiac cycle, transforming from a saddle D-shape during systole to a flat (and less eccentric) D-shape during diastole. Prosthetic MV devices, including heart valves and annuloplasty rings, are designed based on these two configurations, with the circular design of some prosthetic heart valves (PHVs) being an approximation of the less eccentric, flat D-shape. Characterizing the effects of these geometrical variations on the filling efficiency of the left ventricle (LV) is required to understand why the flat D-shaped annulus is observed in the native MV during diastole in addition to optimizing the design of prosthetic devices. We hypothesize that the D-shaped annulus reduces energy loss during ventricular filling. An experimental left heart simulator (LHS) consisting of a flexible-walled LV physical model was used to characterize the filling efficiency of the two mitral annular geometries. The strength of the dominant vortical structure formed and the energy dissipation rate (EDR) of the measured fields, during the diastolic period of the cardiac cycle, were used as metrics to quantify the filling efficiency. Our results indicated that the O-shaped annulus generates a stronger (25% relative to the D-shaped annulus) vortical structure than that of the D-shaped annulus. It was also found that the O-shaped annulus resulted in higher EDR values throughout the diastolic period of the cardiac cycle. The results support the hypothesis that a D-shaped mitral annulus reduces dissipative energy losses in ventricular filling during diastole and in turn suggests that a symmetric stent design does not provide lower filling efficiency than an equivalent asymmetric design.
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17
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Tan SGD, Kim S, Hon JKF, Leo HL. A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns. PLoS One 2016; 11:e0156580. [PMID: 27258099 PMCID: PMC4892640 DOI: 10.1371/journal.pone.0156580] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/17/2016] [Indexed: 11/18/2022] Open
Abstract
Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve) has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation.
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Affiliation(s)
- Sean Guo-Dong Tan
- Department of Biomedical Engineering, National University of Singapore, Faculty of Engineering, Block E4, #04–08, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Sangho Kim
- Department of Biomedical Engineering, National University of Singapore, Faculty of Engineering, Block E4, #04–08, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Jimmy Kim Fatt Hon
- Department of Surgery, National University of Singapore, Yong Loo Lin School of Medicine, Kent Ridge Road, Singapore 119228, Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Faculty of Engineering, Block E4, #04–08, 4 Engineering Drive 3, Singapore 117583, Singapore
- * E-mail:
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18
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Tan GDS, Leo HL. A D-Shaped Bileaflet Bioprosthesis Which Replicates Physiological Left Ventricular Flow Patterns1. J Med Device 2016. [DOI: 10.1115/1.4033119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Guo-Dong Sean Tan
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, 117583, Singapore
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19
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Santhanakrishnan A, Okafor I, Kumar G, Yoganathan AP. Atrial systole enhances intraventricular filling flow propagation during increasing heart rate. J Biomech 2016; 49:618-23. [PMID: 26895781 DOI: 10.1016/j.jbiomech.2016.01.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/14/2016] [Accepted: 01/28/2016] [Indexed: 11/17/2022]
Abstract
Diastolic fluid dynamics in the left ventricle (LV) has been examined in multiple clinical studies for understanding cardiac function in healthy humans and developing diagnostic measures in disease conditions. The question of how intraventricular filling vortex flow pattern is affected by increasing heart rate (HR) is still unanswered. Previous studies on healthy subjects have shown a correlation between increasing HR and diminished E/A ratio of transmitral peak velocities during early filling (E-wave) to atrial systole (A-wave). We hypothesize that with increasing HR under constant E/A ratio, E-wave contribution to intraventricular vortex propagation is diminished. A physiologic in vitro flow phantom consisting of a LV physical model was used for this study. HR was varied across 70, 100 and 120 beats per minute (bpm) with E/A of 1.1-1.2. Intraventricular flow patterns were characterized using 2D particle image velocimetry measured across three parallel longitudinal (apical-basal) planes in the LV. A pair of counter-rotating vortices was observed during E-wave across all HRs. With increasing HR, diminished vortex propagation occurred during E-wave and atrial systole was found to amplify secondary vorticity production. The diastolic time point where peak vortex circulation occurred was delayed with increasing HR, with peak circulation for 120bpm occurring as late as 90% into diastole near the end of A-wave. The role of atrial systole is elevated for higher HR due to the limited time available for filling. Our baseline findings and analysis approach can be applied to studies of clinical conditions where impaired exercise tolerance is observed.
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Affiliation(s)
- Arvind Santhanakrishnan
- School of Mechanical and Aerospace Engineering, Oklahoma State University, 218 Engineering North, Stillwater, OK 74078, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 315 Ferst Drive, Atlanta, GA 30332, USA.
| | - Ikechukwu Okafor
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Gautam Kumar
- Division of Cardiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Ajit P Yoganathan
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, 315 Ferst Drive, Atlanta, GA 30332, USA.
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20
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Okafor IU, Santhanakrishnan A, Chaffins BD, Mirabella L, Oshinski JN, Yoganathan AP. Cardiovascular magnetic resonance compatible physical model of the left ventricle for multi-modality characterization of wall motion and hemodynamics. J Cardiovasc Magn Reson 2015; 17:51. [PMID: 26112155 PMCID: PMC4482204 DOI: 10.1186/s12968-015-0154-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Accepted: 06/10/2015] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The development of clinically applicable fluid-structure interaction (FSI) models of the left heart is inherently challenging when using in vivo cardiovascular magnetic resonance (CMR) data for validation, due to the lack of a well-controlled system where detailed measurements of the ventricular wall motion and flow field are available a priori. The purpose of this study was to (a) develop a clinically relevant, CMR-compatible left heart physical model; and (b) compare the left ventricular (LV) volume reconstructions and hemodynamic data obtained using CMR to laboratory-based experimental modalities. METHODS The LV was constructed from optically clear flexible silicone rubber. The geometry was based off a healthy patient's LV geometry during peak systole. The LV phantom was attached to a left heart simulator consisting of an aorta, atrium, and systemic resistance and compliance elements. Experiments were conducted for heart rate of 70 bpm. Wall motion measurements were obtained using high speed stereo-photogrammetry (SP) and cine-CMR, while flow field measurements were obtained using digital particle image velocimetry (DPIV) and phase-contrast magnetic resonance (PC-CMR). RESULTS The model reproduced physiologically accurate hemodynamics (aortic pressure = 120/80 mmHg; cardiac output = 3.5 L/min). DPIV and PC-CMR results of the center plane flow within the ventricle matched, both qualitatively and quantitatively, with flow from the atrium into the LV having a velocity of about 1.15 m/s for both modalities. The normalized LV volume through the cardiac cycle computed from CMR data matched closely to that from SP. The mean difference between CMR and SP was 5.5 ± 3.7%. CONCLUSIONS The model presented here can thus be used for the purposes of: (a) acquiring CMR data for validation of FSI simulations, (b) determining accuracy of cine-CMR reconstruction methods, and
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Affiliation(s)
- Ikechukwu U Okafor
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Arvind Santhanakrishnan
- School of Mechanical & Aerospace Engineering, Oklahoma State University, Stillwater, OK, USA.
| | - Brandon D Chaffins
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
| | - Lucia Mirabella
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
| | - John N Oshinski
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
- Department of Radiology and Imaging Sciences, School of Medicine, Emory University, Atlanta, GA, USA.
| | - Ajit P Yoganathan
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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21
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Witschey WR, Zhang D, Contijoch F, McGarvey JR, Lee M, Takebayashi S, Aoki C, Han Y, Han J, Barker AJ, Pilla JJ, Gorman RC, Gorman JH. The Influence of Mitral Annuloplasty on Left Ventricular Flow Dynamics. Ann Thorac Surg 2015; 100:114-121. [PMID: 25975941 DOI: 10.1016/j.athoracsur.2015.02.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 02/03/2015] [Accepted: 02/10/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Mitral valve (MV) repair using annuloplasty rings is the preferred method of treatment for MV regurgitation, but the impact of annuloplasty ring placement on left ventricular intraventricular flow has not been studied. METHODS Annuloplasty rings of varying sizes were placed in 5 healthy sheep (intercommissural ring sizes were 24, 26, 28, 30, and 32 mm), and three-dimensional phase contrast magnetic resonance imaging (4D flow MRI) was performed before and 1 week after ring placement. RESULTS Normal diastolic flow consisted of diastolic intraventricular vortices that naturally unwound during systole. Postsurgical intraventricular flow was highly disturbed in all sheep, and the disturbance was greatest for undersized rings. Ring size was highly correlated with the diastolic inflow angle (Pearson's r = -0.62, p < 0.1, 95% confidence interval: -0.92 to 0.14). There was a mean angle increase of mean diastolic inflow angle increase of 12.3 degrees (< 30 mm, p < 0.01, 95% confidence interval: 4.8 to 19.6) for rings less than 30 mm. There was an inverse relationship between peak velocity and annuloplasty ring area (Pearson's r = -0.80, p < 0.05, 95% confidence interval: -0.96 to -0.2). Transmitral pressure gradients increased significantly from baseline 0.73 ± 0.18 mm Hg to after annuloplasty 2.31 ± 1.04 mm Hg (p < 0.05). CONCLUSIONS Mitral valve annuloplasty ring placement disturbs normal left ventricular intraventricular flow patterns, and the degree of disturbance is closely associated with annuloplasty ring size.
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Affiliation(s)
- Walter Rt Witschey
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Donald Zhang
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Francisco Contijoch
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeremy R McGarvey
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Madonna Lee
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Satoshi Takebayashi
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Chikashi Aoki
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Yuchi Han
- Cardiovascular Division, University of Pennsylvania, Philadelphia, PA, USA
| | - Joyce Han
- Cardiovascular Division, University of Pennsylvania, Philadelphia, PA, USA
| | | | - James J Pilla
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, University of Pennsylvania, Philadelphia, PA, USA
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22
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Su B, Kabinejadian F, Phang HQ, Kumar GP, Cui F, Kim S, Tan RS, Hon JKF, Allen JC, Leo HL, Zhong L. Numerical Modeling of Intraventricular Flow during Diastole after Implantation of BMHV. PLoS One 2015; 10:e0126315. [PMID: 25961285 PMCID: PMC4427484 DOI: 10.1371/journal.pone.0126315] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 03/31/2015] [Indexed: 12/20/2022] Open
Abstract
This work presents a numerical simulation of intraventricular flow after the implantation of a bileaflet mechanical heart valve at the mitral position. The left ventricle was simplified conceptually as a truncated prolate spheroid and its motion was prescribed based on that of a healthy subject. The rigid leaflet rotation was driven by the transmitral flow and hence the leaflet dynamics were solved using fluid-structure interaction approach. The simulation results showed that the bileaflet mechanical heart valve at the mitral position behaved similarly to that at the aortic position. Sudden area expansion near the aortic root initiated a clockwise anterior vortex, and the continuous injection of flow through the orifice resulted in further growth of the anterior vortex during diastole, which dominated the intraventricular flow. This flow feature is beneficial to preserving the flow momentum and redirecting the blood flow towards the aortic valve. To the best of our knowledge, this is the first attempt to numerically model intraventricular flow with the mechanical heart valve incorporated at the mitral position using a fluid-structure interaction approach. This study facilitates future patient-specific studies.
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Affiliation(s)
- Boyang Su
- National Heart Research Institute of Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Foad Kabinejadian
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Hui Qun Phang
- Department of Surgery, National University of Singapore, Singapore, Singapore
| | | | - Fangsen Cui
- Institute of High Performance Computing, ASTAR, Singapore, Singapore
| | - Sangho Kim
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Ru San Tan
- National Heart Research Institute of Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Jimmy Kim Fatt Hon
- Department of Surgery, National University of Singapore, Singapore, Singapore
| | | | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Liang Zhong
- National Heart Research Institute of Singapore, National Heart Centre Singapore, Singapore, Singapore
- Duke-NUS Graduate Medical School, Singapore, Singapore
- * E-mail:
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23
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de Vecchi A, Gomez A, Pushparajah K, Schaeffter T, Nordsletten DA, Simpson JM, Penney GP, Smith NP. Towards a fast and efficient approach for modelling the patient-specific ventricular haemodynamics. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 116:3-10. [PMID: 25157924 DOI: 10.1016/j.pbiomolbio.2014.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/12/2014] [Indexed: 11/17/2022]
Abstract
Computer modelling of the heart has emerged over the past decade as a powerful technique to explore the cardiovascular pathophysiology and inform clinical diagnosis. The current state-of-the-art in biophysical modelling requires a wealth of, potentially invasive, clinical data for the parametrisation and validation of the models, a process that is still too long and complex to be compatible with the clinical decision-making time. Therefore, there remains a need for models that can be quickly customised to reconstruct physical processes difficult to measure directly in patients. In this paper, we propose a less resource-intensive approach to modelling, whereby computational fluid-dynamics (CFD) models are constrained exclusively by boundary motion derived from imaging data through a validated wall tracking algorithm. These models are generated and parametrised based solely on ultrasound data, whose acquisition is fast, inexpensive and routine in all patients. To maximise the time and computational efficiency, a semi-automated pipeline is embedded in an image processing workflow to personalise the models. Applying this approach to two patient cases, we demonstrate this tool can be directly used in the clinic to interpret and complement the available clinical data by providing a quantitative indication of clinical markers that cannot be easily derived from imaging, such as pressure gradients and the flow energy.
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Affiliation(s)
- A de Vecchi
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - A Gomez
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - K Pushparajah
- Evelina London Children's Hospital, London SE1 7EH, UK
| | - T Schaeffter
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - D A Nordsletten
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - J M Simpson
- Evelina London Children's Hospital, London SE1 7EH, UK
| | - G P Penney
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - N P Smith
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK.
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24
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Choi YJ, Vedula V, Mittal R. Computational Study of the Dynamics of a Bileaflet Mechanical Heart Valve in the Mitral Position. Ann Biomed Eng 2014; 42:1668-80. [DOI: 10.1007/s10439-014-1018-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/19/2014] [Indexed: 10/25/2022]
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Zheng X, Xue Q, Mittal R. Computational Study of Hemodynamic Effects of Abnormal E/A Ratio on Left Ventricular Filling. J Biomech Eng 2014; 136:061005. [DOI: 10.1115/1.4027268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Indexed: 11/08/2022]
Abstract
Three-dimensional numerical simulations are employed to investigate the hemodynamic effects of abnormal E/A ratios on left ventricular filling. The simulations are performed in a simplified geometric model of the left ventricle (LV) in conjunction with a specified endocardial motion. The model has been carefully designed to match the important geometric and flow parameters under the physiological conditions. A wide range of E/A ratios from 0 to infinity is employed with the aim to cover all the possible stages of left ventricle diastolic dysfunction (DD). The effects of abnormal E/A ratios on vortex dynamics, flow propagation velocity, energy consumption as well as flow transport and mixing are extensively discussed. Our results are able to confirm some common findings reported by the previous studies, and also uncover some interesting new features.
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Affiliation(s)
- Xudong Zheng
- Assistant Professor Department of Mechanical Engineering, University of Maine, Boardman Hall 213 A, Orono, ME 04473 e-mail:
| | - Qian Xue
- Department of Mechanical Engineering, University of Maine, Orono, ME 04473
| | - Rajat Mittal
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
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Su B, Zhong L, Wang XK, Zhang JM, Tan RS, Allen JC, Tan SK, Kim S, Leo HL. Numerical simulation of patient-specific left ventricular model with both mitral and aortic valves by FSI approach. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2014; 113:474-482. [PMID: 24332277 DOI: 10.1016/j.cmpb.2013.11.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 10/25/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
Intraventricular flow is important in understanding left ventricular function; however, relevant numerical simulations are limited, especially when heart valve function is taken into account. In this study, intraventricular flow in a patient-specific left ventricle has been modelled in two-dimension (2D) with both mitral and aortic valves integrated. The arbitrary Lagrangian-Eulerian (ALE) approach was employed to handle the large mesh deformation induced by the beating ventricular wall and moving leaflets. Ventricular wall deformation was predefined based on MRI data, while leaflet dynamics were predicted numerically by fluid-structure interaction (FSI). Comparisons of simulation results with in vitro and in vivo measurements reported in the literature demonstrated that numerical method in combination with MRI was able to predict qualitatively the patient-specific intraventricular flow. To the best of our knowledge, we are the first to simulate patient-specific ventricular flow taking into account both mitral and aortic valves.
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Affiliation(s)
- Boyang Su
- Biofluid Mechanics Research Laboratory, 2 Engineering Drive 3, Department of Bioengineering, National University of Singapore, 117576 Singapore, Singapore; Cardiac Mechanics Engineering and Physiology Unit, National Heart Centre Singapore, Mistri Wing 17, 3rd Hospital Avenue, 168752 Singapore, Singapore
| | - Liang Zhong
- Cardiac Mechanics Engineering and Physiology Unit, National Heart Centre Singapore, Mistri Wing 17, 3rd Hospital Avenue, 168752 Singapore, Singapore; Duke-NUS Graduate Medical School Singapore, 8 College Road, 169857 Singapore, Singapore.
| | - Xi-Kun Wang
- Maritime Research Centre, Nanyang Technological University, Singapore
| | - Jun-Mei Zhang
- Cardiac Mechanics Engineering and Physiology Unit, National Heart Centre Singapore, Mistri Wing 17, 3rd Hospital Avenue, 168752 Singapore, Singapore
| | - Ru San Tan
- Cardiac Mechanics Engineering and Physiology Unit, National Heart Centre Singapore, Mistri Wing 17, 3rd Hospital Avenue, 168752 Singapore, Singapore; Duke-NUS Graduate Medical School Singapore, 8 College Road, 169857 Singapore, Singapore
| | - John Carson Allen
- Duke-NUS Graduate Medical School Singapore, 8 College Road, 169857 Singapore, Singapore
| | - Soon Keat Tan
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore
| | - Sangho Kim
- Department of Bioengineering, National University of Singapore, Singapore
| | - Hwa Liang Leo
- Department of Bioengineering, National University of Singapore, Singapore
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27
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Wong K, Samaroo G, Ling I, Dembitsky W, Adamson R, del Álamo JC, May-Newman K. Intraventricular flow patterns and stasis in the LVAD-assisted heart. J Biomech 2014; 47:1485-94. [PMID: 24612721 DOI: 10.1016/j.jbiomech.2013.12.031] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 12/19/2013] [Accepted: 12/21/2013] [Indexed: 12/01/2022]
Abstract
Left ventricular assist device (LVAD) support disrupts the natural blood flow path through the heart, introducing flow patterns associated with thrombosis, especially in the presence of medical devices. The aim of this study was to quantitatively evaluate the flow patterns in the left ventricle (LV) of the LVAD-assisted heart, with a focus on alterations in vortex development and stasis. Particle image velocimetry of a LVAD-supported LV model was performed in a mock circulatory loop. In the Pre-LVAD flow condition, a vortex ring initiating from the LV base migrated toward the apex during diastole and remained in the LV by the end of ejection. During LVAD support, vortex formation was relatively unchanged although vortex circulation and kinetic energy increased with LVAD speed, particularly in systole. However, as pulsatility decreased and aortic valve opening ceased, a region of fluid stasis formed near the left ventricular outflow tract. These findings suggest that LVAD support does not substantially alter vortex dynamics unless cardiac function is minimal. The altered blood flow introduced by the LVAD results in stasis adjacent to the LV outflow tract, which increases the risk of thrombus formation in the heart.
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Affiliation(s)
- K Wong
- Bioengineering Program, San Diego State University, Department of Mechanical Engineering, San Diego, CA 92182-1323, United States
| | - G Samaroo
- Bioengineering Program, San Diego State University, Department of Mechanical Engineering, San Diego, CA 92182-1323, United States
| | - I Ling
- Bioengineering Program, San Diego State University, Department of Mechanical Engineering, San Diego, CA 92182-1323, United States
| | - W Dembitsky
- Mechanical Circulatory Support, Cardiothoracic Surgery, Sharp Memorial Hospital, San Diego, CA 92182-1323, United States
| | - R Adamson
- Mechanical Circulatory Support, Cardiothoracic Surgery, Sharp Memorial Hospital, San Diego, CA 92182-1323, United States
| | - J C del Álamo
- Mechanical and Aerospace Engineering, U.C. San Diego, La Jolla, CA 92093-0411, United States; Institute for Engineering in Medicine, U.C. San Diego, La Jolla, CA 92093, United States
| | - K May-Newman
- Bioengineering Program, San Diego State University, Department of Mechanical Engineering, San Diego, CA 92182-1323, United States.
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Mittnacht AJC, Sengupta PP. The dynamics of mitral valve function: lessons to be learned from three-dimensional echocardiography. J Cardiothorac Vasc Anesth 2014; 28:8-10. [PMID: 24440008 DOI: 10.1053/j.jvca.2013.11.008] [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: 11/13/2013] [Indexed: 11/11/2022]
Affiliation(s)
| | - Partho P Sengupta
- Department of Cardiology, Icahn School of Medicine at Mount Sinai, New York, NY
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Chan BT, Ong CW, Lim E, Abu Osman NA, Al Abed A, Lovell NH, Dokos S. Simulation of left ventricle flow dynamics with dilated cardiomyopathy during the filling phase. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:6289-92. [PMID: 23367367 DOI: 10.1109/embc.2012.6347432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dilated cardiomyopathy (DCM) is a common cardiac disease which leads to the deterioration in cardiac performance. A computational fluid dynamics (CFD) approach can be used to enhance our understanding of the disease, by providing us with a detailed map of the intraventricular flow and pressure distributions. In the present work, effect of ventricular size on the intraventricular flow dynamics and intraventricular pressure gradients (IVPGs) was studied using two different implementation methods, i.e. the geometry-prescribed and the fluid structure interaction (FSI) methods. Results showed that vortex strength and IVPGs are significantly reduced in a dilated heart, leading to an increased risk of thrombus formation and impaired ventricular filling. We suggest FSI method as the ultimate method in studying ventricular dysfunction as it provides additional cardiac disease prognostic factors and more realistic model implementation.
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Affiliation(s)
- B T Chan
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia.
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Le TB, Sotiropoulos F. Fluid-structure interaction of an aortic heart valve prosthesis driven by an animated anatomic left ventricle. JOURNAL OF COMPUTATIONAL PHYSICS 2013; 244:41-62. [PMID: 23729841 PMCID: PMC3667163 DOI: 10.1016/j.jcp.2012.08.036] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We develop a novel large-scale kinematic model for animating the left ventricle (LV) wall and use this model to drive the fluid-structure interaction (FSI) between the ensuing blood flow and a mechanical heart valve prosthesis implanted in the aortic position of an anatomic LV/aorta configuration. The kinematic model is of lumped type and employs a cell-based, FitzHugh-Nagumo framework to simulate the motion of the LV wall in response to an excitation wavefront propagating along the heart wall. The emerging large-scale LV wall motion exhibits complex contractile mechanisms that include contraction (twist) and expansion (untwist). The kinematic model is shown to yield global LV motion parameters that are well within the physiologic range throughout the cardiac cycle. The FSI between the leaflets of the mechanical heart valve and the blood flow driven by the dynamic LV wall motion and mitral inflow is simulated using the curvilinear immersed boundary (CURVIB) method [1, 2] implemented in conjunction with a domain decomposition approach. The computed results show that the simulated flow patterns are in good qualitative agreement with in vivo observations. The simulations also reveal complex kinematics of the valve leaflets, thus, underscoring the need for patient-specific simulations of heart valve prosthesis and other cardiac devices.
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Affiliation(s)
- Trung Bao Le
- Saint Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, 2 Third Ave SE, Minneapolis, MN 55414
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31
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Mangual JO, Kraigher-Krainer E, De Luca A, Toncelli L, Shah A, Solomon S, Galanti G, Domenichini F, Pedrizzetti G. Comparative numerical study on left ventricular fluid dynamics after dilated cardiomyopathy. J Biomech 2013; 46:1611-7. [DOI: 10.1016/j.jbiomech.2013.04.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 04/15/2013] [Accepted: 04/15/2013] [Indexed: 10/26/2022]
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Zhong L, Su B, Zhang JM, Leo HL, Tan RS. FSI simulation of intra-ventricular flow in patient-specific ventricular model with both mitral and aortic valves. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:703-706. [PMID: 24109784 DOI: 10.1109/embc.2013.6609597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Investigating the intra-ventricular flow is the most important to understand the left ventricular function. In this study, we proposed a fluid-structure interaction (FSI) approach to simulate the blood flow in patient-specific model by combining both mitral and aortic valves. To accommodate the large mesh deformation, moving arbitrary Lagrangian-Eulerian (ALE) meshes were used for moving ventricular wall and rotating leaflets of valves. The left ventricular wall was predescribed according to the points acquired from magnetic resonance image (MRI). Mitral and aortic valves were integrated into the model by assuming each leaflet as a rigid body. Fluid-structure interaction (FSI) approach was adopted to capture the rapid motion of leaflets. The simulation results were qualitatively similar to the measurements reported in literatures. To the best of our knowledge, this is the first to simulate the patient-specific ventricular flow with the presence of both mitral and aortic valves.
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WONG KELVINKL, SUN ZHONGHUA, TU JIYUAN. MEDICAL IMAGING AND COMPUTER-AIDED FLOW ANALYSIS OF A HEART WITH ATRIAL SEPTAL DEFECT. J MECH MED BIOL 2012. [DOI: 10.1142/s0219519412500248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Computer-aided magnetic resonance (MR) fluid motion tracking and cardiac vorticity quantification of the right atrial flow is implemented in this study to suggest a new method for the diagnosis of an atrial septal defect (ASD). MR signals of blood moving in a cardiac chamber can be represented as an image and vary in intensity at every consecutive cardiac phase. A method was devised to perform flow analysis using MR imaging without modification of scan mode or protocol that allows velocity encoding. A single vortex or multiple vortices may appear in the cardiac chamber. However, velocity fields in any flow scenario are normally unable to reveal information for a concise analysis; therefore, in addition to velocity maps, vorticity flow maps on which the velocity field is superimposed are presented. Through a case study, the difference in vortex strengths pre- and post-atrial septal occlusion can be examined, and the results can be verified using computational fluid dynamics. Based on this framework, the degree of vortical flow was assessed for the right atrium of a subject with atrial septal defect. A relationship can be established between right atrial vorticity and the ASD. As such, there is clear utility of the developed system in its potential as a prognostic and investigative tool for the quantitative assessment of cardiac abnormalities parallel to examining magnetic resonance images.
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Affiliation(s)
- KELVIN K. L. WONG
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, VIC 3083, Australia
| | - ZHONGHUA SUN
- Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth 6845, Australia
| | - JIYUAN TU
- School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, VIC 3083, Australia
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Chen R, Zhao BW, Wang B, Tang HL, Li P, Pan M, Xu LL. Assessment of left ventricular hemodynamics and function of patients with uremia by vortex formation using vector flow mapping. Echocardiography 2012; 29:1081-90. [PMID: 22694735 DOI: 10.1111/j.1540-8175.2012.01737.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A novel echocardiographic method, vector flow mapping (VFM), acquires velocity vector from color Doppler velocity data. The purpose of this study was to evaluate whether VFM could provide useful information on intracardiac flow and helpful to evaluate left ventricular (LV) function. Thirty-eight patients with uremia undergoing hemodialysis and 30 healthy volunteers were enrolled. The maximum vector velocity, maximum diameter and duration of the intracardiac vortex were measured using VFM software during systole and diastole. The maximum vector velocity of the vortex and the peak velocities at the basal septum and lateral mitral annulus measured by tissue Doppler imaging (TDI) were correlated. The maximum diameter and duration of vortex formation were significantly higher in uremic patients compared with the control group during the ejection phase (40.6 ± 7.9 cm/sec vs. 28.1 ± 3.9 cm/sec; 297.1 ± 22.1 msec vs. 145.4 ± 19.3 msec, all P < 0.001). The maximal diameters of the vortex were higher in uremic patients compared with the control group during diastole (25.6 ± 3.4 mm vs. 16.4 ± 2.1 mm; 34.3 ± 3.1 mm vs. 26.8 ± 3.9 mm; 37.5 ± 2.4 mm vs. 20.9 ± 2.1 mm; all P < 0.001). The maximum vector velocities were lower in mid-diastole and late diastole (23.6 ± 2.3 cm/sec vs. 45.2 ± 3.7 cm/sec; 31.9 ± 2.9 cm/sec vs. 54.7 ± 3.2 cm/sec, all P < 0.001). There was a correlation between the maximum vector velocity of the vortex in mid-diastole and E'/A' at the septum and lateral mitral annulus (r = 0.70, r = 0.76, P < 0.001). Vortex can be utilized to provide intracardiac dynamic information using VFM and it may be a good supplement for evaluating LV function.
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Affiliation(s)
- Ran Chen
- Department of Diagnostic Ultrasound and Echocardiography, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine and Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, Hangzhou, China
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Medical image diagnostics based on computer-aided flow analysis using magnetic resonance images. Comput Med Imaging Graph 2012; 36:527-41. [PMID: 22575846 DOI: 10.1016/j.compmedimag.2012.04.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 04/10/2012] [Accepted: 04/12/2012] [Indexed: 11/24/2022]
Abstract
Most of the cardiac abnormalities have an implication on hemodynamics and affect cardiovascular health. Diagnostic imaging modalities such as computed tomography and magnetic resonance imaging provide excellent anatomical information on myocardial structures, but fail to show the cardiac flow and detect heart defects in vivo condition. The computerized technique for fluid motion estimation by pixel intensity tracking based on magnetic resonance signals represents a promising technique for functional assessment of cardiovascular disease, as it can provide functional information of the heart in addition to analysis of its anatomy. Cardiovascular flow characteristics can be measured in both normal controls and patients with cardiac abnormalities such as atrial septal defect, thus, enabling identification of the underlying causes of these flow phenomena. This review paper focuses on an overview of a flow analysis scheme based on computer-aided evaluation of magnetic resonance intensity images, in comparison with other commonly used medical imaging modalities. Details of the proposed technique are provided with validations being conducted at selected abnormal cardiovascular patients. It is expected that this new technique can potentially extend applications for characterizing cardiovascular defects and their hemodynamic behavior.
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Gao H, Claus P, Amzulescu MS, Stankovic I, D'hooge J, Voigt JU. How to optimize intracardiac blood flow tracking by echocardiographic particle image velocimetry? Exploring the influence of data acquisition using computer-generated data sets. Eur Heart J Cardiovasc Imaging 2011; 13:490-9. [DOI: 10.1093/ejechocard/jer285] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Intuitive visualization and quantification of intraventricular convection in acute ischemic left ventricular failure during early diastole using color Doppler-based echocardiographic vector flow mapping. Int J Cardiovasc Imaging 2011; 28:1035-47. [DOI: 10.1007/s10554-011-9932-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
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Towards patient-specific cardiovascular modeling system using the immersed boundary technique. Biomed Eng Online 2011; 10:52. [PMID: 21682851 PMCID: PMC3141582 DOI: 10.1186/1475-925x-10-52] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 06/17/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Previous research shows that the flow dynamics in the left ventricle (LV) reveal important information about cardiac health. This information can be used in early diagnosis of patients with potential heart problems. The current study introduces a patient-specific cardiovascular-modelling system (CMS) which simulates the flow dynamics in the LV to facilitate physicians in early diagnosis of patients before heart failure. METHODS The proposed system will identify possible disease conditions and facilitates early diagnosis through hybrid computational fluid dynamics (CFD) simulation and time-resolved magnetic resonance imaging (4-D MRI). The simulation is based on the 3-D heart model, which can simultaneously compute fluid and elastic boundary motions using the immersed boundary method. At this preliminary stage, the 4-D MRI is used to provide an appropriate comparison. This allows flexible investigation of the flow features in the ventricles and their responses. RESULTS The results simulate various flow rates and kinetic energy in the diastole and systole phases, demonstrating the feasibility of capturing some of the important characteristics of the heart during different phases. However, some discrepancies exist in the pulmonary vein and aorta flow rate between the numerical and experimental data. Further studies are essential to investigate and solve the remaining problems before using the data in clinical diagnostics. CONCLUSIONS The results show that by using a simple reservoir pressure boundary condition (RPBC), we are able to capture some essential variations found in the clinical data. Our approach establishes a first-step framework of a practical patient-specific CMS, which comprises a 3-D CFD model (without involving actual hemodynamic data yet) to simulate the heart and the 4-D PC-MRI system. At this stage, the 4-D PC-MRI system is used for verification purpose rather than input. This brings us closer to our goal of developing a practical patient-specific CMS, which will be pursued next. We anticipate that in the future, this hybrid system can potentially identify possible disease conditions in LV through comprehensive analysis and facilitates physicians in early diagnosis of probable cardiac problems.
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40
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Hu Y, Shi L, Parameswaran S, Smirnov S, He Z. Left Ventricular Vortex Under Mitral Valve Edge-to-Edge Repair. Cardiovasc Eng Technol 2010; 1:235-243. [PMID: 21666755 DOI: 10.1007/s13239-010-0022-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mitral valve (MV) edge-to-edge repair (ETER) changes MV geometry by approximation of MV leaflets, and impacts left ventricle (LV) filling fluid mechanics. The purpose of this study was to investigate LV vortex with MV ETER during diastole. A computational MV-LV model was developed with MV ETER at the central free edges of the anterior and posterior leaflets. It was supposed that LV would elongate apically during diastole. The elongation deformation was controlled by the intraventricular flow rate. MV leaflets were modeled as a semi-prolate sphere with two symmetrical circular orifices and fixed at the maximum valve opening. MV chordae were neglected. FLUENT was used to simulate blood flow through the MV and in the LV. MV ETER generated two jets deflected laterally toward the LV wall in rapid LV filling. The jets impinged the LV wall obliquely and moved apically along the LV wall. Jet energy was primarily lost near the impingement. The jet from each MV orifice was surrounded by a vortex ring. The two vortex rings dissipated at the end of diastole. The total energy loss increased inversely with the MV orifice area. The atrio-ventricular pressure gradient was adverse near the end of diastole and possibly in diastasis. Reduction of the total orifice area led to more increment in the transmitral pressure drop than in the transmitral velocity. In conclusion, during diastole, two deflected jets from the MV under ETER impinged the LV wall. Major energy loss occurred around the jet impingement. Two vortex rings dissipated at the end of diastole with little storage of inflow energy for blood ejection in the following process of systole. MV ETER increased energy loss and lowered LV filling efficiency. The maintaining of a larger orifice area after ETER might not significantly increase energy loss in the LV during diastole and the transmitral pressure drop. The adverse pressure gradient from the atrium to the LV might be the mechanism of MV closure in the late diastole.
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Affiliation(s)
- Yingying Hu
- Department of Mechanical Engineering, Texas Tech University, 7th St. and Boston Ave., PO Box 41021, Lubbock 79409-1021, TX, USA
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Garcia D, Del Alamo JC, Tanne D, Yotti R, Cortina C, Bertrand E, Antoranz JC, Perez-David E, Rieu R, Fernandez-Aviles F, Bermejo J. Two-dimensional intraventricular flow mapping by digital processing conventional color-Doppler echocardiography images. IEEE TRANSACTIONS ON MEDICAL IMAGING 2010; 29:1701-13. [PMID: 20562044 DOI: 10.1109/tmi.2010.2049656] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions. Combining color-Doppler velocities with LV wall positions, the cross-beam blood velocities were calculated using the continuity equation under a planar flow assumption. To validate the algorithm, 2D Doppler flow mapping and laser particle image velocimetry (PIV) measurements were carried out in an atrio-ventricular duplicator. Phase-contrast magnetic resonance (MR) acquisitions were used to measure in vivo the error due to the 2D flow assumption and to potential scan-plane misalignment. Finally, the applicability of the Doppler technique was tested in the clinical setting. In vitro experiments demonstrated that the new method yields an accurate quantitative description of the main vortex that forms during the cardiac cycle (mean error for vortex radius, position and circulation). MR image analysis evidenced that the error due to the planar flow assumption is close to 15% and does not preclude the characterization of major vortex properties neither in the normal nor in the dilated LV. These results are yet to be confirmed by a head-to-head clinical validation study. Clinical Doppler studies showed that the method is readily applicable and that a single large anterograde vortex develops in the healthy ventricle while supplementary retrograde swirling structures may appear in the diseased heart. The proposed echocardiographic method based on the continuity equation is fast, clinically-compliant and does not require complex training. This technique will potentially enable investigators to study of additional quantitative aspects of intraventricular flow dynamics in the clinical setting by high-throughput processing conventional color-Doppler images.
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Affiliation(s)
- Damien Garcia
- CRCHUM-Research Centre, University of Montreal Hospital, Montreal, QC H2L2W5, Canada
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42
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Affiliation(s)
- Carl Johan Carlhäll
- Department of Clinical Physiology, University Hospital and Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
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Wong KKL, Tu J, Kelso RM, Worthley SG, Sanders P, Mazumdar J, Abbott D. Cardiac flow component analysis. Med Eng Phys 2009; 32:174-88. [PMID: 20022796 DOI: 10.1016/j.medengphy.2009.11.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 11/19/2009] [Accepted: 11/22/2009] [Indexed: 11/24/2022]
Abstract
In a chamber of the heart, large-scale vortices are shown to exist as the result of the dynamic blood flow and unique morphological changes of the chamber wall. As the cardiovascular flow varies over a cardiac cycle, there is a need for a robust quantification method to analyze its vorticity and circulation. We attempt to measure vortex characteristics by means of two-dimensional vorticity maps and vortex circulation. First, we develop vortex component analysis by segmenting the vortices using an data clustering algorithm before histograms of their vorticity distribution are generated. The next stage is to generate the statistics of the vorticity maps for each phase of the cardiac cycle to allow analysis of the flow. This is followed by evaluating the circulation of each segmented vortex. The proposed approach is dedicated to examining vortices within the human heart chamber. The vorticity field can indicate the strength and number of large-scale vortices in the chamber. We provide the results of the flow analysis after vorticity map segmentation and the statistical properties that characterize the vorticity components. The success of the cardiac measurement and analysis is illustrated by a case study of the right atrium. Our investigation shows that it is possible to utilize a data clustering algorithm to segment vortices after vorticity mapping, and that the vorticity and circulation analysis of a chamber vorticity can provide new insights into the blood flow within the cardiovascular structure.
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Affiliation(s)
- Kelvin K L Wong
- School of Aerospace, Mechanical & Manufacturing Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia.
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Del Alamo JC, Marsden AL, Lasheras JC. Recent advances in the application of computational mechanics to the diagnosis and treatment of cardiovascular disease. Rev Esp Cardiol 2009; 62:781-805. [PMID: 19709514 PMCID: PMC6089365 DOI: 10.1016/s1885-5857(09)72359-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
During the last 30 years, research into the pathogenesis and progression of cardiovascular disease has had to employ a multidisciplinary approach involving a wide range of subject areas, from molecular and cell biology to computational mechanics and experimental solid and fluid mechanics. In general, research was driven by the need to provide answers to questions of critical importance for disease management. Ongoing improvements in the spatial resolution of medical imaging equipment coupled to an exponential growth in the capacity, flexibility and speed of computational techniques have provided a valuable opportunity for numerical simulations and complex experimental techniques to make a contribution to improving the diagnosis and clinical management of many forms of cardiovascular disease. This paper contains a review of recent progress in the numerical simulation of cardiovascular mechanics, focusing on three particular areas: patient-specific modeling and the optimization of surgery in pediatric cardiology, evaluating the risk of rupture in aortic aneurysms, and noninvasive characterization of intraventricular flow in the management of heart failure.
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Affiliation(s)
- Juan C Del Alamo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, California, USA
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del Álamo JC, Marsden AL, Lasheras JC. Avances en mecánica computacional para el diagnóstico y tratamiento de la enfermedad cardiovascular. Rev Esp Cardiol 2009. [DOI: 10.1016/s0300-8932(09)71692-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Cardiac Flow Analysis Applied to Phase Contrast Magnetic Resonance Imaging of the Heart. Ann Biomed Eng 2009; 37:1495-515. [DOI: 10.1007/s10439-009-9709-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 04/28/2009] [Indexed: 01/05/2023]
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Loerakker S, Cox L, van Heijst G, de Mol B, van de Vosse F. Influence of dilated cardiomyopathy and a left ventricular assist device on vortex dynamics in the left ventricle. Comput Methods Biomech Biomed Engin 2008; 11:649-60. [PMID: 18979303 DOI: 10.1080/10255840802469379] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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