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Vector Flow Mapping in Mitral Valve Disease: a Novel Method for the Assessment of Flow Mechanics and Their Potential Implications for Mitral Valve Repair. CURRENT CARDIOVASCULAR IMAGING REPORTS 2015. [DOI: 10.1007/s12410-015-9358-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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102
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Choi YJ, Constantino J, Vedula V, Trayanova N, Mittal R. A New MRI-Based Model of Heart Function with Coupled Hemodynamics and Application to Normal and Diseased Canine Left Ventricles. Front Bioeng Biotechnol 2015; 3:140. [PMID: 26442254 PMCID: PMC4585083 DOI: 10.3389/fbioe.2015.00140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/31/2015] [Indexed: 11/22/2022] Open
Abstract
A methodology for the simulation of heart function that combines an MRI-based model of cardiac electromechanics (CE) with a Navier–Stokes-based hemodynamics model is presented. The CE model consists of two coupled components that simulate the electrical and the mechanical functions of the heart. Accurate representations of ventricular geometry and fiber orientations are constructed from the structural magnetic resonance and the diffusion tensor MR images, respectively. The deformation of the ventricle obtained from the electromechanical model serves as input to the hemodynamics model in this one-way coupled approach via imposed kinematic wall velocity boundary conditions and at the same time, governs the blood flow into and out of the ventricular volume. The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver. The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart. We also discuss the potential of coupled CE and hemodynamics models for various clinical applications.
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Affiliation(s)
- Young Joon Choi
- Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA ; Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA
| | - Jason Constantino
- Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA ; Department of Biomedical Engineering, Johns Hopkins University , Baltimore, MD , USA
| | - Vijay Vedula
- Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA
| | - Natalia Trayanova
- Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA ; Department of Biomedical Engineering, Johns Hopkins University , Baltimore, MD , USA
| | - Rajat Mittal
- Department of Mechanical Engineering, Johns Hopkins University , Baltimore, MD , USA ; Institute for Computational Medicine, Johns Hopkins University , Baltimore, MD , USA
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103
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Nguyen VT, Wibowo SN, Leow YA, Nguyen HH, Liang Z, Leo HL. A Patient-Specific Computational Fluid Dynamic Model for Hemodynamic Analysis of Left Ventricle Diastolic Dysfunctions. Cardiovasc Eng Technol 2015; 6:412-29. [DOI: 10.1007/s13239-015-0244-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 09/07/2015] [Indexed: 10/23/2022]
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104
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Song Z, Borazjani I. The Role of Shape and Heart Rate on the Performance of the Left Ventricle. J Biomech Eng 2015; 137:114501. [PMID: 26312776 DOI: 10.1115/1.4031468] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Indexed: 11/08/2022]
Abstract
The left ventricle function is to pump the oxygenated blood through the circulatory system. Ejection fraction is the main noninvasive parameter for detecting heart disease (healthy >55%), and it is thought to be the main parameter affecting efficiency. However, the effects of other parameters on efficiency have yet to be investigated. We investigate the effect of heart rate and left ventricle shape by carrying out 3D numerical simulations of a left ventricle at different heart rates and perturbed geometries under constant, normal ejection fraction. The simulation using the immersed boundary method provide the 3D flow and pressure fields, which enable direct calculation of a new hemodynamic efficiency (H-efficiency) parameter, which does not depend on any reference pressure. The H-efficiency is defined as the ratio of flux of kinetic energy (useful power) to the total cardiac power into the left ventricle control volume. Our simulations show that H-efficiency is not that sensitive to heart rate but is maximized at around normal heart rate (72 bpm). Nevertheless, it is more sensitive to the shape of the left ventricle, which affects the H-efficiency by as much as 15% under constant ejection fraction.
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105
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Altered left ventricular vortex ring formation by 4-dimensional flow magnetic resonance imaging after repair of atrioventricular septal defects. J Thorac Cardiovasc Surg 2015; 150:1233-40.e1. [PMID: 26282608 DOI: 10.1016/j.jtcvs.2015.07.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/01/2015] [Accepted: 07/15/2015] [Indexed: 11/22/2022]
Abstract
OBJECTIVES During normal left ventricular (LV) filling, a vortex ring structure is formed distal to the left atrioventricular valve (LAVV). Vortex structures contribute to efficient flow organization. We aimed to investigate whether LAVV abnormality in patients with a corrected atrioventricular septal defect (AVSD) has an impact on vortex ring formation. METHODS Whole-heart 4D flow MRI was performed in 32 patients (age: 26 ± 12 years), and 30 healthy subjects (age: 25 ± 14 years). Vortex ring cores were detected at peak early (E-peak) and peak late filling (A-peak). When present, the 3-dimensional position and orientation of the vortex ring was defined, and the circularity index was calculated. Through-plane flow over the LAVV, and the vortex formation time (VFT), were quantified to analyze the relationship of vortex flow with the inflow jet. RESULTS Absence of a vortex ring during E-peak (healthy subjects 0%, vs patients 19%; P = .015), and A-peak (healthy subjects 10% vs patients 44%; P = .008) was more frequent in patients. In 4 patients, this was accompanied by a high VFT (5.1-7.8 vs 2.4 ± 0.6 in healthy subjects), and in another 2 patients with abnormal valve anatomy. In patients compared with controls, the vortex cores had a more-anterior and apical position, closer to the ventricular wall, with a more-elliptical shape and oblique orientation. The shape of the vortex core closely resembled the valve shape, and its orientation was related to the LV inflow direction. CONCLUSIONS This study quantitatively shows the influence of abnormal LAVV and LV inflow on 3D vortex ring formation during LV inflow in patients with corrected AVSD, compared with healthy subjects.
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106
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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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107
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Westerdale JC, Adrian R, Squires K, Chaliki H, Belohlavek M. Effects of Bileaflet Mechanical Mitral Valve Rotational Orientation on Left Ventricular Flow Conditions. Open Cardiovasc Med J 2015; 9:62-8. [PMID: 26312080 PMCID: PMC4541318 DOI: 10.2174/1874192401509010062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/10/2015] [Accepted: 05/12/2015] [Indexed: 11/22/2022] Open
Abstract
We studied left ventricular flow patterns for a range of rotational orientations of a bileaflet mechanical heart valve (MHV) implanted in the mitral position of an elastic model of a beating left ventricle (LV). The valve was rotated through 3 angular positions (0, 45, and 90 degrees) about the LV long axis. Ultrasound scans of the elastic LV were obtained in four apical 2-dimensional (2D) imaging projections, each with 45 degrees of separation. Particle imaging velocimetry was performed during the diastolic period to quantify the in-plane velocity field obtained by computer tracking of diluted microbubbles in the acquired ultrasound projections. The resulting velocity field, vorticity, and shear stresses were statistically significantly altered by angular positioning of the mechanical valve, although the results did not show any specific trend with the valve angular position and were highly dependent on the orientation of the imaging plane with respect to the valve. We conclude that bileaflet MHV orientation influences hemodynamics of LV filling. However, determination of ‘optimal’ valve orientation cannot be made without measurement techniques that account for the highly 3-dimensional (3D) intraventricular flow.
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Affiliation(s)
- John C Westerdale
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona, USA
| | - Ronald Adrian
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona, USA
| | - Kyle Squires
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona, USA
| | - Hari Chaliki
- Division of Cardiovascular Disease, Mayo Clinic, Scottsdale, Arizona, USA
| | - Marek Belohlavek
- Division of Cardiovascular Disease, Mayo Clinic, Scottsdale, Arizona, USA
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108
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Martínez-Legazpi P, Bermejo J, Benito Y, Yotti R, Pérez del Villar C, González-Mansilla A, Barrio A, Villacorta E, Sánchez PL, Fernández-Avilés F, del Álamo JC. Reply. J Am Coll Cardiol 2015; 65:2574-5. [DOI: 10.1016/j.jacc.2015.01.068] [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: 12/30/2014] [Accepted: 01/26/2015] [Indexed: 10/23/2022]
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109
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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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110
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Töger J, Bidhult S, Revstedt J, Carlsson M, Arheden H, Heiberg E. Independent validation of four-dimensional flow MR velocities and vortex ring volume using particle imaging velocimetry and planar laser-Induced fluorescence. Magn Reson Med 2015; 75:1064-75. [PMID: 25940239 DOI: 10.1002/mrm.25683] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/10/2015] [Accepted: 02/10/2015] [Indexed: 11/11/2022]
Abstract
PURPOSE This study aimed to: (i) present and characterize a phantom setup for validation of four-dimensional (4D) flow using particle imaging velocimetry (PIV) and planar laser-induced fluorescence (PLIF); (ii) validate 4D flow velocity measurements using PIV; and (iii) validate 4D flow vortex ring volume (VV) using PLIF. METHODS A pulsatile pump and a tank with a 25-mm nozzle were constructed. PIV measurements (1.5 × 1.5 mm pixels, temporal resolution 10 ms) were obtained on two occasions. The 4D flow (3 × 3 × 3 mm voxels, temporal resolution 50 ms) was acquired using SENSE = 2. VV was quantified using PLIF and 4D flow. RESULTS PIV showed excellent day-to-day stability (R(2) = 0.99, bias -0.04 ± 0.72 cm/s). The 4D flow mean velocities agreed well with PIV (R(2) = 0.95, bias 0.16 ± 2.65 cm/s). Peak velocities in 4D flow were underestimated by 7-18% compared with PIV (y = 0.79x + 2.7, R(2) = 0.96, -12 ± 5%). VV showed excellent agreement between PLIF and 4D flow (R(2) = 0.99, 2.4 ± 1.5 mL). CONCLUSION This study shows: (i) The proposed phantom enables reliable validation of 4D flow. (ii) 4D flow velocities show good agreement with PIV, but peak velocities were underestimated due to low spatial and temporal resolution. (iii) Vortex ring volume (VV) can be quantified using 4D flow.
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Affiliation(s)
- Johannes Töger
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden.,Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden
| | - Sebastian Bidhult
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden.,Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden
| | - Johan Revstedt
- Department of Energy Sciences, Faculty of Engineering, Lund University, Lund, Sweden
| | - Marcus Carlsson
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden
| | - Håkan Arheden
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden
| | - Einar Heiberg
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden.,Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden.,Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden
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111
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Effect of the Mitral Valve’s Anterior Leaflet on Axisymmetry of Transmitral Vortex Ring. Ann Biomed Eng 2015; 43:2349-60. [DOI: 10.1007/s10439-015-1302-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
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112
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Stugaard M, Koriyama H, Katsuki K, Masuda K, Asanuma T, Takeda Y, Sakata Y, Itatani K, Nakatani S. Energy loss in the left ventricle obtained by vector flow mapping as a new quantitative measure of severity of aortic regurgitation: a combined experimental and clinical study. ACTA ACUST UNITED AC 2015; 16:723-30. [DOI: 10.1093/ehjci/jev035] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/05/2015] [Indexed: 11/14/2022]
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113
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Pasipoularides A, Vlachos PP, Little WC. Vortex formation time is not an index of ventricular function. J Cardiovasc Transl Res 2015; 8:54-8. [PMID: 25609509 DOI: 10.1007/s12265-015-9607-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 01/06/2015] [Indexed: 11/26/2022]
Abstract
The diastolic intraventricular ring vortex formation and pinch-off process may provide clinically useful insights into diastolic function in health and disease. The vortex ring formation time (FT) concept, based on hydrodynamic experiments dealing with unconfined (large tank) flow, has attracted considerable attention and popularity. Dynamic conditions evolving within the very confined space of a filling, expansible ventricular chamber with relaxing and rebounding, and viscoelastic muscular boundaries diverge from unconfined (large tank) flow and encompass rebounding walls' suction and myocardial relaxation. Indeed, clinical/physiological findings seeking validation in vivo failed to support the notion that FT is an index of normal/abnormal diastolic ventricular function. Therefore, FT as originally proposed cannot and should not be utilized as such an index. Evidently, physiologically accurate models accounting for coupled hydrodynamic and (patho)physiological myocardial wall interactions with the intraventricular flow are still needed to enhance our understanding and yield diastolic function indices useful and reliable in the clinical setting.
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114
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Chan BT, Lim E, Ong CW, Abu Osman NA. Effect of spatial inlet velocity profiles on the vortex formation pattern in a dilated left ventricle. Comput Methods Biomech Biomed Engin 2015; 18:90-6. [DOI: 10.1080/10255842.2013.779683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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115
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Khalafvand SS, Zhong L, Ng EYK. Three-dimensional CFD/MRI modeling reveals that ventricular surgical restoration improves ventricular function by modifying intraventricular blood flow. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:1044-1056. [PMID: 24753501 DOI: 10.1002/cnm.2643] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 01/10/2014] [Accepted: 03/22/2014] [Indexed: 06/03/2023]
Abstract
Surgical ventricular restoration (SVR) is designed to normalize distorted ventricular shape and size in patients with left ventricular (LV) dysfunction and akinetic and dyskinetic segments. This study is aimed to quantify the characteristics of LV as a pump for a case before and after SVR, which is followed by coronary artery bypass grafting (CABG). We hypothesize that SVR+CABG improves heart flow. A patient with heart failure had magnetic resonance (MR) scans before and 4 months after SVR. LV endocardial geometries were semi-automated segmented and reconstructed using our customized algorithm. The arbitrary Lagrangian-Eulerian formulation of Navier-Stokes equations was solved to derive the flow patterns and calculate pressure differences in LV. After SVR, LV ejection fraction increased from 34% to 48% in patient but was still lower than normal (70%). Second, LV vortices were stronger than pre-surgery but still weaker than normal. The maximum pressure differences between ventricular base and apex increased from 180 to 400 Pa during diastole, from 252 to 560 Pa during systole, respectively. As anticipated, SVR reduced LV volumes and augmented LV ejection fraction. Three-dimensional CFD/MRI modeling suggests that improved diastolic and systolic ventricular function after SVR is associated with changes in intraventricular blood flow.
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Affiliation(s)
- S S Khalafvand
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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116
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Contribution of the Diastolic Vortex Ring to Left Ventricular Filling. J Am Coll Cardiol 2014; 64:1711-21. [DOI: 10.1016/j.jacc.2014.06.1205] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 05/20/2014] [Accepted: 06/02/2014] [Indexed: 11/22/2022]
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117
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Elbaz MSM, Calkoen EE, Westenberg JJM, Lelieveldt BPF, Roest AAW, van der Geest RJ. Vortex flow during early and late left ventricular filling in normal subjects: quantitative characterization using retrospectively-gated 4D flow cardiovascular magnetic resonance and three-dimensional vortex core analysis. J Cardiovasc Magn Reson 2014; 16:78. [PMID: 25270083 PMCID: PMC4177574 DOI: 10.1186/s12968-014-0078-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/01/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND LV diastolic vortex formation has been suggested to critically contribute to efficient blood pumping function, while altered vortex formation has been associated with LV pathologies. Therefore, quantitative characterization of vortex flow might provide a novel objective tool for evaluating LV function. The objectives of this study were 1) assess feasibility of vortex flow analysis during both early and late diastolic filling in vivo in normal subjects using 4D Flow cardiovascular magnetic resonance (CMR) with retrospective cardiac gating and 3D vortex core analysis 2) establish normal quantitative parameters characterizing 3D LV vortex flow during both early and late ventricular filling in normal subjects. METHODS With full ethical approval, twenty-four healthy volunteers (mean age: 20±10 years) underwent whole-heart 4D Flow CMR. The Lambda2-method was used to extract 3D LV vortex ring cores from the blood flow velocity field during early (E) and late (A) diastolic filling. The 3D location of the center of vortex ring core was characterized using cylindrical cardiac coordinates (Circumferential, Longitudinal (L), Radial (R)). Comparison between E and A filling was done with a paired T-test. The orientation of the vortex ring core was measured and the ring shape was quantified by the circularity index (CI). Finally, the Spearman's correlation between the shapes of mitral inflow pattern and formed vortex ring cores was tested. RESULTS Distinct E- and A-vortex ring cores were observed with centers of A-vortex rings significantly closer to the mitral valve annulus (E-vortex L=0.19±0.04 versus A-vortex L=0.15±0.05; p=0.0001), closer to the ventricle's long-axis (E-vortex: R=0.27±0.07, A-vortex: R=0.20±0.09, p=0.048) and more elliptical in shape (E-vortex: CI=0.79±0.09, A-vortex: CI=0.57±0.06; <0.001) compared to E-vortex. The circumferential location and orientation relative to LV long-axis for both E- and A-vortex ring cores were similar. Good to strong correlation was found between vortex shape and mitral inflow shape through both the annulus (r=0.66) and leaflet tips (r=0.83). CONCLUSIONS Quantitative characterization and comparison of 3D vortex rings in LV inflow during both early and late diastolic phases is feasible in normal subjects using retrospectively-gated 4D Flow CMR, with distinct differences between early and late diastolic vortex rings.
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Affiliation(s)
- Mohammed S M Elbaz
- />Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, C3-Q room 54, Albinusdreef 2, Leiden, 2333 ZA The Netherlands
| | - Emmeline E Calkoen
- />Department of Paediatric Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jos J M Westenberg
- />Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, C3-Q room 54, Albinusdreef 2, Leiden, 2333 ZA The Netherlands
| | - Boudewijn P F Lelieveldt
- />Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, C3-Q room 54, Albinusdreef 2, Leiden, 2333 ZA The Netherlands
- />Department of Intelligent Systems, Delft University of Technology, Delft, The Netherlands
| | - Arno A W Roest
- />Department of Paediatric Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Rob J van der Geest
- />Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, C3-Q room 54, Albinusdreef 2, Leiden, 2333 ZA The Netherlands
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118
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Pedrizzetti G, Domenichini F. Left Ventricular Fluid Mechanics: The Long Way from Theoretical Models to Clinical Applications. Ann Biomed Eng 2014; 43:26-40. [PMID: 25186434 DOI: 10.1007/s10439-014-1101-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 08/25/2014] [Indexed: 12/25/2022]
Affiliation(s)
- Gianni Pedrizzetti
- Dipartimento di Ingegneria e Architettura, University of Trieste, P.le Europa 1, 34127, Trieste, Italy,
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119
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Malakan Rad E, Awad S, Hijazi ZM. Congenital left ventricular outpouchings: a systematic review of 839 cases and introduction of a novel classification after two centuries. CONGENIT HEART DIS 2014; 9:498-511. [PMID: 25159202 DOI: 10.1111/chd.12214] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/08/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Congenital left ventricular outpouchings (LVOs) are reported under five overlapping and poorly defined terms including left ventricular accessory chamber, left ventricular aneurysm (LVA), left ventricular diverticulum (LVD), double-chambered LV, and accessory left ventricle. Diagnostic criteria are frequently mixed and not mutually exclusive. They convey no information regarding treatment strategy and prognosis. OBJECTIVES The aim of this systematic review is to provide a clear and inclusive classification, with therapeutic and prognostic implications, for congenital LVOs. DATA SOURCES We performed three separate sets of search on three subjects including "congenital left ventricular outpouchings," "important and simply measurable markers of left ventricular function," and "relationship of mechanics of intraventricular blood flow and optimal vortex formation in left ventricle and elliptical geometry of LV." STUDY ELIGIBILITY CRITERIA We enrolled case series, review articles, and case reports with literature review. All types of acquired LVO's were excluded. STUDY APPRAISAL AND SYNTHESIS METHODS We studied the abstracts of all searched articles. We focused on diagnostic criteria and patients' outcome. To examine the validity and reliability of the novel classification, fifteen previous studies were revisited using the novel classification. RESULTS A total of 20 papers from 11 countries fulfilled our inclusion criteria. The age of patients ranged from prenatal age to geriatric age range. Diagnostic criteria were clearly stated only for two of the above five terms (i.e., congenital LVA and congenital LVD). Cases with mixed diagnostic criteria were frequent.Elliptical geometry of left ventricle was found to have significant impact on effective blood flow mechanics in LV. A simple inclusive classification for congenital LVOs, with therapeutic and prognostic implications, was introduced. CONCLUSION The cornerstone of this classification is elliptical LV geometry. Large-type IIc LVO have dismal prognosis, if left untreated. LVO type I and small LVO type IIa have the best prognosis.
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Affiliation(s)
- Elaheh Malakan Rad
- Section of Pediatric Cardiology, Children's Medical Center (Pediatric Center of Excellence), Tehran University of Medical Sciences, Tehran, Iran
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120
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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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121
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Lagrangian postprocessing of computational hemodynamics. Ann Biomed Eng 2014; 43:41-58. [PMID: 25059889 DOI: 10.1007/s10439-014-1070-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 07/11/2014] [Indexed: 10/25/2022]
Abstract
Recent advances in imaging, modeling, and computing have rapidly expanded our capabilities to model hemodynamics in the large vessels (heart, arteries, and veins). This data encodes a wealth of information that is often under-utilized. Modeling (and measuring) blood flow in the large vessels typically amounts to solving for the time-varying velocity field in a region of interest. Flow in the heart and larger arteries is often complex, and velocity field data provides a starting point for investigating the hemodynamics. This data can be used to perform Lagrangian particle tracking, and other Lagrangian-based postprocessing. As described herein, Lagrangian methods are necessary to understand inherently transient hemodynamic conditions from the fluid mechanics perspective, and to properly understand the biomechanical factors that lead to acute and gradual changes of vascular function and health. The goal of the present paper is to review Lagrangian methods that have been used in post-processing velocity data of cardiovascular flows.
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122
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Agati L, Cimino S, Tonti G, Cicogna F, Petronilli V, De Luca L, Iacoboni C, Pedrizzetti G. Quantitative analysis of intraventricular blood flow dynamics by echocardiographic particle image velocimetry in patients with acute myocardial infarction at different stages of left ventricular dysfunction. ACTA ACUST UNITED AC 2014; 15:1203-12. [DOI: 10.1093/ehjci/jeu106] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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123
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Pedrizzetti G, La Canna G, Alfieri O, Tonti G. The vortex—an early predictor of cardiovascular outcome? Nat Rev Cardiol 2014; 11:545-53. [DOI: 10.1038/nrcardio.2014.75] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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124
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Garcia J, Larose E, Pibarot P, Kadem L. On the evaluation of vorticity using cardiovascular magnetic resonance velocity measurements. J Biomech Eng 2014; 135:124501. [PMID: 24026138 DOI: 10.1115/1.4025385] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 09/12/2013] [Indexed: 11/08/2022]
Abstract
Vorticity and vortical structures play a fundamental role affecting the evaluation of energetic aspects (mainly left ventricle work) of cardiovascular function. Vorticity can be derived from cardiovascular magnetic resonance (CMR) imaging velocity measurements. However, several numerical schemes can be used to evaluate the vorticity field. The main objective of this work is to assess different numerical schemes used to evaluate the vorticity field derived from CMR velocity measurements. We compared the vorticity field obtained using direct differentiation schemes (eight-point circulation and Chapra) and derivate differentiation schemes (Richardson 4* and compact Richardson 4*) from a theoretical velocity field and in vivo CMR velocity measurements. In all cases, the effect of artificial spatial resolution up-sampling and signal-to-noise ratio (SNR) on vorticity computation was evaluated. Theoretical and in vivo results showed that the eight-point circulation method underestimated vorticity. Up-sampling evaluation showed that the artificial improvement of spatial resolution had no effect on mean absolute vorticity estimation but it affected SNR for all methods. The Richardson 4* method and its compact version were the most accurate and stable methods for vorticity magnitude evaluation. Vorticity field determination using the eight-point circulation method, the most common method used in CMR, has reduced accuracy compared to other vorticity schemes. Richardson 4* and its compact version showed stable SNR using both theoretical and in vivo data.
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125
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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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126
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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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127
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Rodríguez Muñoz D, Moya Mur JL, Fernández-Golfín C, Becker Filho DC, González Gómez A, Fernández Santos S, Lázaro Rivera C, Rincón Díaz LM, Casas Rojo E, Zamorano Gómez JL. Left Ventricular Vortices as Observed by Vector Flow Mapping: Main Determinants and their Relation to Left Ventricular Filling. Echocardiography 2014; 32:96-105. [DOI: 10.1111/echo.12584] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
| | - José Luis Moya Mur
- Department of Cardiology; Ramón y Cajal University Hospital; Madrid Spain
| | | | | | | | | | | | | | - Eduardo Casas Rojo
- Department of Cardiology; Ramón y Cajal University Hospital; Madrid Spain
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128
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Monacelli F, Odetti P, Sartini M, Parodi A, Brunelli C, Rosa G. Cardioprotection and anticholinesterases in patients with Alzheimer's disease: time for reappraisal. Dement Geriatr Cogn Dis Extra 2014; 4:45-50. [PMID: 24711813 PMCID: PMC3977226 DOI: 10.1159/000357124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background/Aim Traditional risk factors, like impaired transmitral flow in diastolic filling [vortex formation time (VFT) as echocardiographic parameter], contribute to Alzheimer's disease (AD). Moreover, we observed that acetylcholinesterase inhibitors provide a significant cardioprotection. We assessed the pathogenetic role of VFT as early cardiovascular risk factor in 23 AD patients and 24 controls. Results The results showed no statistical difference between the two groups, but the VFT values were significantly lower in nontreated AD patients, and higher value were observed in AD patients treated with anticholinesterases. Conclusions The results support the beneficial effects of anticholinesterases on the cardiovascular system of AD patients. Thus, the transition to evidence-based medicine and an in vivo model of cardiomyocytes might strengthen these results.
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Affiliation(s)
- Fiammetta Monacelli
- Sections of Geriatrics, Department of Internal Medicine and Medical Specialties (DiMI), Genoa, Italy
| | - Patrizio Odetti
- Sections of Geriatrics, Department of Internal Medicine and Medical Specialties (DiMI), Genoa, Italy
| | - Marina Sartini
- Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy
| | - Antonello Parodi
- Sections of Cardiology, Department of Internal Medicine and Medical Specialties (DiMI), Genoa, Italy
| | - Claudio Brunelli
- Sections of Cardiology, Department of Internal Medicine and Medical Specialties (DiMI), Genoa, Italy
| | - Gianmarco Rosa
- Sections of Cardiology, Department of Internal Medicine and Medical Specialties (DiMI), Genoa, Italy
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129
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Bermejo J, Benito Y, Alhama M, Yotti R, Martínez-Legazpi P, Del Villar CP, Pérez-David E, González-Mansilla A, Santa-Marta C, Barrio A, Fernández-Avilés F, Del Álamo JC. Intraventricular vortex properties in nonischemic dilated cardiomyopathy. Am J Physiol Heart Circ Physiol 2014; 306:H718-29. [PMID: 24414062 DOI: 10.1152/ajpheart.00697.2013] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vortices may have a role in optimizing the mechanical efficiency and blood mixing of the left ventricle (LV). We aimed to characterize the size, position, circulation, and kinetic energy (KE) of LV main vortex cores in patients with nonischemic dilated cardiomyopathy (NIDCM) and analyze their physiological correlates. We used digital processing of color-Doppler images to study flow evolution in 61 patients with NIDCM and 61 age-matched control subjects. Vortex features showed a characteristic biphasic temporal course during diastole. Because late filling contributed significantly to flow entrainment, vortex KE reached its maximum at the time of the peak A wave, storing 26 ± 20% of total KE delivered by inflow (range: 1-74%). Patients with NIDCM showed larger and stronger vortices than control subjects (circulation: 0.008 ± 0.007 vs. 0.006 ± 0.005 m(2)/s, respectively, P = 0.02; KE: 7 ± 8 vs. 5 ± 5 mJ/m, P = 0.04), even when corrected for LV size. This helped confining the filling jet in the dilated ventricle. The vortex Reynolds number was also higher in the NIDCM group. By multivariate analysis, vortex KE was related to the KE generated by inflow and to chamber short-axis diameter. In 21 patients studied head to head, Doppler measurements of circulation and KE closely correlated with phase-contract magnetic resonance values (intraclass correlation coefficient = 0.82 and 0.76, respectively). Thus, the biphasic nature of filling determines normal vortex physiology. Vortex formation is exaggerated in patients with NIDCM due to chamber remodeling, and enlarged vortices are helpful for ameliorating convective pressure losses and facilitating transport. These findings can be accurately studied using ultrasound.
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Affiliation(s)
- Javier Bermejo
- Department of Cardiology, Hospital General Universitario Gregorio Marañón, Facultad de Medicina, Universidad Complutense de Madrid, and Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
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130
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Mehregan F, Tournoux F, Muth S, Pibarot P, Rieu R, Cloutier G, Garcia D. Doppler vortography: a color Doppler approach to quantification of intraventricular blood flow vortices. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:210-21. [PMID: 24210865 PMCID: PMC3864856 DOI: 10.1016/j.ultrasmedbio.2013.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/05/2013] [Accepted: 09/09/2013] [Indexed: 05/11/2023]
Abstract
We propose a new approach to quantification of intracardiac vorticity based on conventional color Doppler images -Doppler vortography. Doppler vortography relies on the centrosymmetric properties of the vortices. Such properties induce particular symmetries in the Doppler flow data that can be exploited to describe the vortices quantitatively. For this purpose, a kernel filter was developed to derive a parameter, the blood vortex signature (BVS), that allows detection of the main intracardiac vortices and estimation of their core vorticities. The reliability of Doppler vortography was assessed in mock Doppler fields issued from simulations and in vitro data. Doppler vortography was also tested in patients and compared with vector flow mapping by echocardiography. Strong correlations were obtained between Doppler vortography-derived and ground-truth vorticities (in silico: r2 = 0.98, in vitro: r2 = 0.86, in vivo: r2 = 0.89). Our results indicate that Doppler vortography is a potentially promising echocardiographic tool for quantification of vortex flow in the left ventricle.
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Affiliation(s)
- Forough Mehregan
- RUBIC, Research Unit of Biomechanics and Imaging in Cardiology
- CRCHUM, Research Center, University of Montreal Hospital, Canada
| | - François Tournoux
- Department of Echocardiography, CHUM, University of Montreal Hospital, Canada
| | - Stéphan Muth
- RUBIC, Research Unit of Biomechanics and Imaging in Cardiology
- CRCHUM, Research Center, University of Montreal Hospital, Canada
| | - Philippe Pibarot
- Department of Medicine, Laval University, and Québec Heart & Lung Institute
| | - Régis Rieu
- Aix-Marseille University, CNRS, UMR 7287, ISM GIBoc, Marseille, France
| | - Guy Cloutier
- CRCHUM, Research Center, University of Montreal Hospital, Canada
- LBUM, Laboratory of Biorheology and Medical Ultrasonics
- Department of Radiology, Radio-Oncology and Nuclear Medicine, and Institute of Biomedical Engineering, University of Montreal, Canada
| | - Damien Garcia
- RUBIC, Research Unit of Biomechanics and Imaging in Cardiology
- CRCHUM, Research Center, University of Montreal Hospital, Canada
- Department of Radiology, Radio-Oncology and Nuclear Medicine, and Institute of Biomedical Engineering, University of Montreal, Canada
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131
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Ghosh E, Kovács SJ. The vortex formation time to diastolic function relation: assessment of pseudonormalized versus normal filling. Physiol Rep 2013; 1:e00170. [PMID: 24400169 PMCID: PMC3871482 DOI: 10.1002/phy2.170] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 10/30/2013] [Accepted: 11/01/2013] [Indexed: 01/18/2023] Open
Abstract
In early diastole, the suction pump feature of the left ventricle opens the mitral valve and aspirates atrial blood. The ventricle fills via a blunt profiled cylindrical jet of blood that forms an asymmetric toroidal vortex ring inside the ventricle whose growth has been quantified by the standard (dimensionless) expression for vortex formation time, VFTstandard = {transmitral velocity time integral}/{mitral orifice diameter}. It can differentiate between hearts having distinguishable early transmitral (Doppler E-wave) filling patterns. An alternative validated expression, VFTkinematic reexpresses VFTstandard by incorporating left heart, near “constant-volume pump” physiology thereby revealing VFTkinematic's explicit dependence on maximum rate of longitudinal chamber expansion (E′). In this work, we show that VFTkinematic can differentiate between hearts having indistinguishable E-wave patterns, such as pseudonormal (PN; 0.75 < E/A < 1.5 and E/E′ > 8) versus normal. Thirteen age-matched normal and 12 PN data sets (738 total cardiac cycles), all having normal LVEF, were selected from our Cardiovascular Biophysics Laboratory database. Doppler E-, lateral annular E′-waves, and M-mode data (mitral leaflet separation, chamber dimension) was used to compute VFTstandard and VFTkinematic. VFTstandard did not differentiate between groups (normal [3.58 ± 1.06] vs. PN [4.18 ± 0.79], P = 0.13). In comparison, VFTkinematic for normal (3.15 ± 1.28) versus PN (4.75 ± 1.35) yielded P = 0.006. Hence, the applicability of VFTkinematic for diastolic function quantitation has been broadened to include analysis of PN filling patterns in age-matched groups.
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Affiliation(s)
- Erina Ghosh
- Department of Biomedical Engineering, School of Engineering and Applied Science, Washington University in St Louis St. Louis, Missouri
| | - Sándor J Kovács
- Department of Biomedical Engineering, School of Engineering and Applied Science, Washington University in St Louis St. Louis, Missouri ; Cardiovascular Biophysics Laboratory, Cardiovascular Division, Department of Internal Medicine, School of Medicine, Washington University in St Louis St. Louis, Missouri
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132
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Xenos M, Karakitsos D, Labropoulos N, Tassiopoulos A, Bilfinger TV, Bluestein D. Comparative study of flow in right-sided and left-sided aortas: numerical simulations in patient-based models. Comput Methods Biomech Biomed Engin 2013; 18:414-25. [DOI: 10.1080/10255842.2013.805210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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133
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Rodriguez Muñoz D, Markl M, Moya Mur JL, Barker A, Fernández-Golfín C, Lancellotti P, Zamorano Gómez JL. Intracardiac flow visualization: current status and future directions. Eur Heart J Cardiovasc Imaging 2013; 14:1029-38. [PMID: 23907342 DOI: 10.1093/ehjci/jet086] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Non-invasive cardiovascular imaging initially focused on heart structures, allowing the visualization of their motion and inferring its functional status from it. Colour-Doppler and cardiac magnetic resonance (CMR) have allowed a visual approach to intracardiac flow behaviour, as well as measuring its velocity at single selected spots. Recently, the application of new technologies to medical use and, particularly, to cardiology has allowed, through different algorithms in CMR and applications of ultrasound-related techniques, the description and analysis of flow behaviour in all points and directions of the selected region, creating the opportunity to incorporate new data reflecting cardiac performance to cardiovascular imaging. The following review provides an overview of the currently available imaging techniques that enable flow visualization, as well as its present and future applications based on the available literature and on-going works.
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Affiliation(s)
- Daniel Rodriguez Muñoz
- Department of Cardiology, Ramón y Cajal University Hospital, Ctra. de Colmenar, Km 9, 100, PO 28031 Madrid, Spain
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134
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Antonini C, Bernagozzi I, Jung S, Poulikakos D, Marengo M. Water drops dancing on ice: how sublimation leads to drop rebound. PHYSICAL REVIEW LETTERS 2013; 111:014501. [PMID: 23863003 DOI: 10.1103/physrevlett.111.014501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 04/06/2013] [Indexed: 06/02/2023]
Abstract
Drop rebound is a spectacular event that appears after impact on hydrophobic or superhydrophobic surfaces but can also be induced through the so-called Leidenfrost effect. Here we demonstrate that drop rebound can also originate from another physical phenomenon, the solid substrate sublimation. Through drop impact experiments on a superhydrophobic surface, a hot plate, and solid carbon dioxide (commonly known as dry ice), we compare drop rebound based on three different physical mechanisms, which apparently share nothing in common (superhydrophobicity, evaporation, and sublimation), but lead to the same rebound phenomenon in an extremely wide temperature range, from 300 °C down to even below -79 °C. The formation and unprecedented visualization of an air vortex ring around an impacting drop are also reported.
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Affiliation(s)
- C Antonini
- Department of Engineering, University of Bergamo, Viale Marconi 5, 24044 Dalmine (BG), Italy
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135
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McGarvey JR, Kondo N, Takebe M, Koomalsingh KJ, Witschey WRT, Barker AJ, Markl M, Takebayashi S, Shimaoka T, Gorman JH, Gorman RC, Pilla JJ. Directed epicardial assistance in ischemic cardiomyopathy: flow and function using cardiac magnetic resonance imaging. Ann Thorac Surg 2013; 96:577-85. [PMID: 23810178 DOI: 10.1016/j.athoracsur.2013.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Heart failure after myocardial infarction (MI) is a result of increased myocardial workload, adverse left ventricular (LV) geometric remodeling, and less efficient LV fluid movement. In this study we utilize cardiac magnetic resonance imaging to evaluate ventricular function and flow after placement of a novel directed epicardial assist device. METHODS Five swine underwent posterolateral MI and were allowed to remodel for 12 weeks. An inflatable bladder was positioned centrally within the infarct and secured with mesh. The device was connected to an external gas exchange pump, which inflated and deflated in synchrony with the cardiac cycle. Animals then underwent cardiac magnetic resonance imaging during active epicardial assistance and with no assistance. RESULTS Active epicardial assistance of the infarct showed immediate improvement in LV function and intraventricular flow. Ejection fraction significantly improved from 26.0% ± 4.9% to 37.3% ± 4.5% (p < 0.01). End-systolic volume (85.5 ± 12.7 mL versus 70.1 ± 11.9 mL, p < 0.01) and stroke volume (28.5 ± 4.4 mL versus 39.9 ± 3.1 mL, p = 0.03) were also improved with assistance. End-diastolic volume and regurgitant fraction did not change with treatment. Regional LV flow improved both qualitatively and quantitatively during assistance. Unassisted infarct regional flow showed highly discoordinate blood movement with very slow egress from the posterolateral wall. Large areas of stagnant flow were also identified. With assistance, posterolateral wall blood velocities improved significantly during both systole (26.4% ± 3.2% versus 12.6% ± 1.2% maximum velocity; p < 0.001) and diastole (54.3% ± 9.3% versus 24.2% ± 2.5% maximum velocity; p < 0.01). CONCLUSIONS Directed epicardial assistance can improve LV function and flow in ischemic cardiomyopathy. This novel device may provide a valuable alternative to currently available heart failure therapies.
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Affiliation(s)
- Jeremy R McGarvey
- Gorman Cardiovascular Research Group, Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104-5156, USA
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Pagel PS, Hudetz JA. Chronic pressure-overload hypertrophy attenuates vortex formation time in patients with severe aortic stenosis and preserved left ventricular systolic function undergoing aortic valve replacement. J Cardiothorac Vasc Anesth 2013; 27:660-4. [PMID: 23727466 DOI: 10.1053/j.jvca.2013.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Transmitral blood flow produces a vortex ring that enhances the hydraulic efficiency of early left ventricular (LV) filling. The effect of pressure-overload hypertrophy on the duration of LV vortex ring formation (vortex formation time [VFT]) is unknown. The current investigation tested the hypothesis that chronic LV pressure-overload hypertrophy produced by severe aortic stenosis (AS) reduces VFT in patients with preserved LV systolic function undergoing aortic valve replacement. DESIGN Observational study. SETTING Veterans Affairs Medical Center. PARTICIPANTS After the Institutional Review Board's approval, 8 patients (7 men and 1 woman; age, 62±5 y; and ejection fraction, 59%±5%) with AS (peak pressure gradient, 81±22 mmHg; aortic valve area, 0.78±0.25 cm(2)) scheduled for aortic valve replacement were compared with 8 patients (all men; age, 63±3 y; and ejection fraction, 60%±7%) without AS undergoing coronary artery bypass graft surgery. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Under general anesthesia, peak early LV filling (E) and atrial systole (A) blood flow velocities and their corresponding velocity-time integrals were obtained using pulse-wave Doppler echocardiography to determine E/A and atrial filling fraction (β). Mitral valve diameter (D) was calculated as the average of minor and major axis lengths obtained in the midesophageal bicommissural and long-axis transesophageal echocardiography imaging planes, respectively. Posterior wall thickness (PWT) was measured at end-diastole using M-mode echocardiography. VFT was calculated as 4×(1-β)×SV/πD(3), where SV = stroke volume measured using thermodilution. Systemic and pulmonary hemodynamics, LV diastolic function, PWT, and VFT were determined during steady-state conditions 30 minutes before cardiopulmonary bypass. Early LV filling was attenuated in patients with AS (eg, E/A, 0.77±0.11 compared with 1.23±0.13; β, 0.43±0.09 compared with 0.35±0.02; p<0.05 for each). LV hypertrophy was observed (PWT, 1.4±0.1 cm compared with 1.1±0.2 cm; p<0.05) and VFT was lower (3.0±0.9 v 4.3±0.5; p<0.05) in patients with versus without AS. Linear regression analysis showed a significant correlation between VFT and PWT (VFT = -2.57 ×PWT + 6.81; r(2) = 0.345; p = 0.017). CONCLUSION The results indicated that pressure-overload hypertrophy produced by AS reduced VFT in patients with normal LV systolic function undergoing aortic valve replacement.
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Affiliation(s)
- Paul S Pagel
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA.
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137
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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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138
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Left ventricular flow analysis: recent advances in numerical methods and applications in cardiac ultrasound. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:395081. [PMID: 23690874 PMCID: PMC3652115 DOI: 10.1155/2013/395081] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/19/2013] [Indexed: 11/18/2022]
Abstract
The left ventricle (LV) pumps oxygenated blood from the lungs to the rest of the body through systemic circulation. The efficiency of such a pumping function is dependent on blood flow within the LV chamber. It is therefore crucial to accurately characterize LV hemodynamics. Improved understanding of LV hemodynamics is expected to provide important clinical diagnostic and prognostic information. We review the recent advances in numerical and experimental methods for characterizing LV flows and focus on analysis of intraventricular flow fields by echocardiographic particle image velocimetry (echo-PIV), due to its potential for broad and practical utility. Future research directions to advance patient-specific LV simulations include development of methods capable of resolving heart valves, higher temporal resolution, automated generation of three-dimensional (3D) geometry, and incorporating actual flow measurements into the numerical solution of the 3D cardiovascular fluid dynamics.
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139
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Abe H, Caracciolo G, Kheradvar A, Pedrizzetti G, Khandheria BK, Narula J, Sengupta PP. Contrast echocardiography for assessing left ventricular vortex strength in heart failure: a prospective cohort study. ACTA ACUST UNITED AC 2013; 14:1049-60. [DOI: 10.1093/ehjci/jet049] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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140
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Vortices formed on the mitral valve tips aid normal left ventricular filling. Ann Biomed Eng 2013; 41:1049-61. [PMID: 23389556 DOI: 10.1007/s10439-013-0755-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
Abstract
For the left ventricle (LV) to function as an effective pump it must be able to fill from a low left atrial pressure. However, this ability is lost in patients with heart failure. We investigated LV filling by measuring the cardiac blood flow using 2D phase contrast magnetic resonance imaging and quantified the intraventricular pressure gradients and the strength and location of vortices. In normal subjects, blood flows towards the apex prior to the mitral valve opening, and the mitral annulus moves rapidly away after the valve opens, with both effects enhancing the vortex ring at the mitral valve tips. Instead of being a passive by-product of the process as was previously believed, this ring facilitates filling by reducing convective losses and enhancing the function of the LV as a suction pump. The virtual channel thus created by the vortices may help insure efficient mass transfer for the left atrium to the LV apex. Impairment of this mechanism contributes to diastolic dysfunction, with LV filling becoming dependent on left atrial pressure, which can lead to eventual heart failure. Better understanding of the mechanics of this progression may lead to more accurate diagnosis and treatment of this disease.
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141
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Kanski M, Toger J, Steding-Ehrenborg K, Carlsson M, Heiberg E, Arheden H. Vortex formation ratio in heart failure compared to healthy volunteers at rest and during exercise. J Cardiovasc Magn Reson 2013. [PMCID: PMC3559605 DOI: 10.1186/1532-429x-15-s1-o65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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142
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Nawroth JC, Parker KK. Design standards for engineered tissues. Biotechnol Adv 2012; 31:632-7. [PMID: 23267860 DOI: 10.1016/j.biotechadv.2012.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 12/12/2012] [Accepted: 12/14/2012] [Indexed: 11/16/2022]
Abstract
Traditional technologies are required to meet specific, quantitative standards of safety and performance. In tissue engineering, similar standards will have to be developed to enable routine clinical use and customized tissue fabrication. In this essay, we discuss a framework of concepts leading towards general design standards for tissue-engineering, focusing in particular on systematic design strategies, control of cell behavior, physiological scaling, fabrication modes and functional evaluation.
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Affiliation(s)
- Janna C Nawroth
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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143
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Kim DH, Seo JS, Choi YS, Kim HR, Chung YJ, Yun SC, Song JM, Kang DH, Song JK. Determinants of left ventricular vortex flow parameters assessed by contrast echocardiography in an in vivo animal model. Echocardiography 2012; 30:588-98. [PMID: 23252706 DOI: 10.1111/echo.12075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Various left ventricular (LV) vortex parameters obtained during contrast echocardiography (CE) have been recently described. The aim of this study was to investigate their determinants and associations with conventional hemodynamic variables. METHODS CE was performed and LV pressure was simultaneously measured during pharmacologic inotropic modulation in 8 mongrel dogs. Customized software was used to assess both vortex geometric parameters (vortex depth [VD], length [VL], width [VW], transverse position, and sphericity index [SI]) and pulsatility parameters (relative strength [RS], vortex relative strength [VRS], and vortex pulsation correlation [VPC]). The associations between each of these parameters and conventional indices representing LV systolic and diastolic function were analyzed. RESULTS VD and VW did not change significantly during pharmacologic modulation, whereas VL (P = 0.0034) and SI (P = 0.001) showed significant and progressive linear decreases from baseline during dobutamine infusion. Significant linear changes during positive and negative inotropic modulation were observed in all pulsatiliy parameters (P < 0.01 each). Geometric parameters were critically dependent on LV volume, with pulsatility parameters showing significant positive correlations with heart rate, systolic and diastolic blood pressure (DBP), dp/dtmax , early and late mitral inflow velocities, and peak systolic and diastolic annular velocities. In multivariate analysis, LV end-diastolic volume was a main determinant for VL (r = 0.29, P < 0.001) and VW (r = 0.65, P < 0.001), whereas dp/dtmax for pulsatility parameters (RS [r = 0.61, P < 0.001], VRS [r = 0.46, P < 0.001] and VPC [r = 0.62, P < 0.001]). CONCLUSION Geometric and pulsatility parameters differed in their association with LV geometry and conventional physiologic indices representing LV function. These differences should be considered in interpreting these variables.
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Affiliation(s)
- Dae-Hee Kim
- Cardiac Imaging Center, Asan Heart Institute Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
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144
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Amaki M, Abe H, Sengupta PP. Visualization of blood flow with echocardiography: the future for heart failure diagnosis. Interv Cardiol 2012. [DOI: 10.2217/ica.12.54] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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145
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Zhang H, Liu L, Chen L, Ma N, Zhou L, Liu Y, Li Z, Liu C, Hou R, Zhu S. The evolution of intraventricular vortex during ejection studied by using vector flow mapping. Echocardiography 2012; 30:27-36. [PMID: 22985123 DOI: 10.1111/j.1540-8175.2012.01806.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
AIMS The purpose of this study was to assess the evolution of intraventricular vortex during left ventricular (LV) ejection. METHODS Vector flow mapping was performed in 51 patients with coronary artery disease and LV ejection fraction (EF) >50%, 70 patients with EF <50% (13 with coronary artery disease and 57 with dilated cardiomyopathy), and 62 healthy volunteers. RESULTS In normals and patients with EF >50%, the intraventricular vortex dissipated quickly during early ejection. In patients with EF <50%, the vortex stayed mainly at apex and persisted for a significantly longer time. The evolution of vortex during ejection was significantly correlated with QRS width, EF, fractional shortening, LV outflow velocity time integral, wall motion score index (WMSI), LV dimensions, left atrial diameter, and diastolic mitral annular velocities. LV end-diastolic short diameter and WMSI were the independent determinants of the duration of vortex (R(2) = 0.482, P < 0.001). End-systolic short diameter and apical WMSI were the independent determinants of duration of vortex corrected for ejection time (R(2) = 0.565, P < 0.001). End-systolic short diameter was the independent determinant of percentage change in vortex area during early ejection (R(2) = 0.355, P < 0.001). End-systolic short diameter and ejection time were the independent determinants of percentage change in vortex flow volume (R(2) = 0.415, P < 0.001). CONCLUSIONS In patients with LV systolic dysfunction, the vortex persists during ejection and stays mainly at apex. The vortex evolution during ejection is closely associated with LV dimensions and functions.
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Affiliation(s)
- Haibin Zhang
- Department of Ultrasound, PLA 210th Hospital, Dalian, China
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146
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Stewart KC, Charonko JC, Niebel CL, Little WC, Vlachos PP. Left ventricular vortex formation is unaffected by diastolic impairment. Am J Physiol Heart Circ Physiol 2012; 303:H1255-62. [PMID: 22961866 DOI: 10.1152/ajpheart.00093.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Normal left ventricular (LV) filling occurs rapidly early in diastole caused by a progressive pressure gradient within the ventricle and with a low left atrial pressure. This normal diastolic function is altered in patients with heart failure. Such impairment of diastolic filling is manifested as an abrupt deceleration of the early filling wave velocity. Although variations within the early filling wave have been observed previously, the underlying hydrodynamic mechanisms are not well understood. Previously, it was proposed that the mitral annulus vortex ring formation time was the total duration of early diastolic filling and provided a measure of the efficiency of diastolic filling. However, we found that the favorable LV pressure difference driving early diastolic filling becomes zero simultaneously with the deceleration of the early filling wave propagation velocity and pinch-off of the LV vortex ring. Thus we calculated the vortex ring formation time using the duration of the early diastolic filling wave from its initiation to the time of the early filling wave propagation velocity deceleration when pinch-off occurs. This formation time does not vary with decreasing intraventricular pressure difference or with degree of diastolic dysfunction. Thus we conclude the vortex ring pinch-off occurs before the completion of early diastole, and its formation time remains invariant to changes of diastolic function.
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Affiliation(s)
- Kelley C Stewart
- Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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147
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Le TB, Sotiropoulos F. On the three-dimensional vortical structure of early diastolic flow in a patient-specific left ventricle. EUROPEAN JOURNAL OF MECHANICS. B, FLUIDS 2012; 35:20-24. [PMID: 22773898 PMCID: PMC3388554 DOI: 10.1016/j.euromechflu.2012.01.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We study the formation of the mitral vortex ring during early diastolic filling in a patient-specific left ventricle using direct numerical simulation. The geometry of the left ventricle is reconstructed from Magnetic Resonance Imaging (MRI). The heart wall motion is modeled by a cell-based activation methodology, which yields physiologic kinematics with heart rate equal to 52 beats per minute. We show that the structure of the mitral vortex ring consists of the main vortex ring and trailing vortex tubes, which originate at the heart wall. The trailing vortex tubes play an important role in exciting twisting circumferential instability modes of the mitral vortex ring. At the end of diastole, the vortex ring impinges on the wall and the intraventricular flow transitions to a weak turbulent state. Our results can be used to help interprete and analyze three-dimensional in-vivo flow measurements obtained with MRI.
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Affiliation(s)
- Trung Bao Le
- St. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Fotis Sotiropoulos
- St. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, Minneapolis, MN, USA
- Corresponding author at: Saint Anthony Falls Lab., Dept. Civil Engineering, University of Minnesota, 2 Third Ave SE, Minneapolis, MN 55414. Tel: +1 612 624 2022
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148
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Fluid-dynamics modelling of the human left ventricle with dynamic mesh for normal and myocardial infarction: Preliminary study. Comput Biol Med 2012; 42:863-70. [DOI: 10.1016/j.compbiomed.2012.06.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/06/2012] [Accepted: 06/23/2012] [Indexed: 11/19/2022]
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149
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Töger J, Kanski M, Carlsson M, Kovács SJ, Söderlind G, Arheden H, Heiberg E. Vortex ring formation in the left ventricle of the heart: analysis by 4D flow MRI and Lagrangian coherent structures. Ann Biomed Eng 2012; 40:2652-62. [PMID: 22805980 DOI: 10.1007/s10439-012-0615-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/28/2012] [Indexed: 10/28/2022]
Abstract
Recent studies suggest that vortex ring formation during left ventricular (LV) rapid filling is an optimized mechanism for blood transport, and that the volume of the vortex ring is an important measure. However, due to lack of quantitative methods, the volume of the vortex ring has not previously been studied. Lagrangian Coherent Structures (LCS) is a new flow analysis method, which enables in vivo quantification of vortex ring volume. Therefore, we aimed to investigate if vortex ring volume in the human LV can be reliably quantified using LCS and magnetic resonance velocity mapping (4D PC-MR). Flow velocities were measured using 4D PC-MR in 9 healthy volunteers and 4 patients with dilated ischemic cardiomyopathy. LV LCS were computed from flow velocities and manually delineated in all subjects. Vortex volume in the healthy volunteers was 51 ± 6% of the LV volume, and 21 ± 5% in the patients. Interobserver variability was -1 ± 13% and interstudy variability was -2 ± 12%. Compared to idealized flow experiments, the vortex rings showed additional complexity and asymmetry, related to endocardial trabeculation and papillary muscles. In conclusion, LCS and 4D PC-MR enables measurement of vortex ring volume during rapid filling of the LV.
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Affiliation(s)
- Johannes Töger
- Department of Clinical Physiology, Skåne University Hospital Lund, Lund University, 221 85, Lund, Sweden
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150
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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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