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Darwish A, Papolla C, Rieu R, Kadem L. An Anatomically Shaped Mitral Valve for Hemodynamic Testing. Cardiovasc Eng Technol 2024; 15:374-381. [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] [MESH Headings] [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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2
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Yang K, Wu S, Samuel OW, Zhang H, Ghista DN, Yang D, Wong KKL. A Hybrid Approach for Cardiac Blood Flow Vortex Ring Identification Based on Optical Flow and Lagrangian Averaged Vorticity Deviation. Front Physiol 2021; 12:698405. [PMID: 34539430 PMCID: PMC8440940 DOI: 10.3389/fphys.2021.698405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 08/05/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: The measurement of cardiac blood flow vortex characteristics can help to facilitate the analysis of blood flow dynamics that regulates heart function. However, the complexity of cardiac flow along with other physical limitations makes it difficult to adequately identify the dominant vortices in a heart chamber, which play a significant role in regulating the heart function. Although the existing vortex quantification methods can achieve this goal, there are still some shortcomings: such as low precision, and ignoring the center of the vortex without the description of vortex deformation processes. To address these problems, an optical flow Lagrangian averaged vorticity deviation (Optical flow-LAVD) method is proposed. Methodology: We examined the flow within the right atrium (RA) of the participants’ hearts, by using a single set of scans pertaining to a slice at two-chamber short-axis orientation. Toward adequate extraction of the vortex ring characteristics, a novel approach driven by the Lagrangian averaged vorticity deviation (LAVD) was implemented and applied to characterize the trajectory integral associated with vorticity deviation and the spatial mean of rings, by using phase-contrast magnetic resonance imaging (PC-MRI) datasets as a case study. To interpolate the time frames between every larger discrete frame and minimize the error caused by constructing a continuous velocity field for the integral process of LAVD, we implemented the optical flow as an interpolator and introduced the backward warping as an intermediate frame synthesis basis, which is then used to generate higher quality continuous velocity fields. Results: Our analytical study results showed that the proposed Optical flow-LAVD method can accurately identify vortex ring and continuous velocity fields, based on optical flow information, for yielding high reconstruction outcomes. Compared with the linear interpolation and phased-based frame interpolation methods, our proposed algorithm can generate more accurate synthesized PC-MRI. Conclusion: This study has developed a novel Optical flow-LAVD model to accurately identify cardiac vortex rings, and minimize the associated errors caused by the construction of a continuous velocity field. Our paper presents a superior vortex characteristics detection method that may potentially aid the understanding of medical experts on the dynamics of blood flow within the heart.
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Affiliation(s)
- Ke Yang
- Key Laboratory of Metallurgical Equipment and Control Technology, Ministry of Education, Wuhan University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Shiqian Wu
- School of Information Science and Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Oluwarotimi W Samuel
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Hui Zhang
- Ultrasound Department, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Dhanjoo N Ghista
- University 2020 Foundation, Inc., California City, CA, United States
| | - Di Yang
- Key Laboratory of Metallurgical Equipment and Control Technology, Ministry of Education, Wuhan University of Science and Technology, Wuhan, China.,Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering, Wuhan University of Science and Technology, Wuhan, China
| | - Kelvin K L Wong
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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3
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Xu F, Kenjereš S. Numerical simulations of flow patterns in the human left ventricle model with a novel dynamic mesh morphing approach based on radial basis function. Comput Biol Med 2021; 130:104184. [PMID: 33444850 DOI: 10.1016/j.compbiomed.2020.104184] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022]
Abstract
We present a new numerical simulation framework for prediction of flow patterns in the human left ventricle model. In this study, a radial basis function (RBF) mesh morphing method is developed and applied within the finite-volume computational fluid dynamics (CFD) approach. The numerical simulations are designed to closely mimic details of recent tomographic particle image velocimetry (TomoPIV) experiments. The numerically simulated dynamic motions of the left ventricle and tri-leaflet biological mitral valve are emulated through the RBF morphing method. The arbitrary Lagrangian-Eulerian (ALE) based CFD is performed with the RBF-defined deforming wall boundaries. The results obtained show a good agreement with experiments, confirming the reliability and accuracy of the developed simulation framework.
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Affiliation(s)
- Fei Xu
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology and J. M. Burgerscentrum Research School for Fluid Mechanics, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Saša Kenjereš
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology and J. M. Burgerscentrum Research School for Fluid Mechanics, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
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4
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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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5
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Diagnostic and prognostic significance of cardiovascular vortex formation. J Cardiol 2019; 74:403-411. [DOI: 10.1016/j.jjcc.2019.05.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 12/16/2022]
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Nguyen YN, Tay ELW, Kabinejadian F, Ong CW, Ismail M, Leo HL. Ventricular vortex loss analysis due to various tricuspid valve repair techniques: an ex vivo study. Am J Physiol Heart Circ Physiol 2019; 317:H1312-H1327. [PMID: 31603355 DOI: 10.1152/ajpheart.00150.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The deteriorating nature of severe functional tricuspid regurgitation (FTR) has led to the heightened interest in this pathology. However, therapies are heterogeneous and an ideal technique is uncertain. The hemodynamic impact on the cardiac chamber following therapeutic repairs has not been well studied, while its analysis could be used to predict the treatment success. In this study, the hemodynamics of the right ventricle (RV) after 1) clover edge-to-edge tricuspid repair, and 2) double orifice tricuspid repair was evaluated in three right heart models using an ex vivo pulsatile platform emulating severe FTR with the aid of stereoscopic particle image velocimetry. Although all repairs substantially reduced tricuspid regurgitant area, they resulted in a more than 50% reduction in diastolic tricuspid valve (TV) opening area. Splitting the TV orifice into multiple smaller orifices by both repairs eliminated the ring-shaped vortical structure inside the RV observed in FTR cases. Postrepair RV domain was mostly occupied with irregular vortical features and isolated vortex residuals. Moreover, vortical features varied among repair samples, indicating enhanced sensitivity of RV flow to postrepair TV morphology. Compared with clover repair, double orifice subjected the RV to enhanced swirling motions and exposed more regions to vortical motions, potentially indicating better rinsing and lower risk of mural thrombus formation. Double orifice repair increased the levels of RV mean kinetic energy and viscous energy loss than those observed in clover repair, although the impact of these on the cardiac efficiency remains unclear. These preliminary insights could be used to improve future treatment design and planning.NEW & NOTEWORTHY While clover and double orifice tricuspid repairs markedly improved leaflet coaptation, they substantially reduced diastolic tricuspid opening area. Postrepair right ventricle (RV) exhibited specific hemodynamic traits, including the loss of ring-shaped vortical structure and the enhanced sensitivity of RV flow to postrepair tricuspid valve morphology. Compared with clover technique, double orifice repair led to higher swirling motions in the RV domain, which could indicate lower risk of mural thrombus formation.
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Affiliation(s)
- Yen Ngoc Nguyen
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Edgar Lik Wui Tay
- Department of Cardiology, National University Heart Centre, Singapore
| | - Foad Kabinejadian
- Department of Biomedical Engineering, Tulane University, New Orleans, Louisiana
| | - Chi Wei Ong
- Department of Biomedical Engineering, National University of Singapore, Singapore
| | - Munirah Ismail
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Hwa Liang Leo
- Department of Biomedical Engineering, National University of Singapore, Singapore.,Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
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7
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Kulkarni A, Morisawa D, Gonzalez D, Kheradvar A. Age‐related changes in diastolic function in children: Echocardiographic association with vortex formation time. Echocardiography 2019; 36:1869-1875. [DOI: 10.1111/echo.14479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 08/09/2019] [Accepted: 08/21/2019] [Indexed: 11/29/2022] Open
Affiliation(s)
- Aparna Kulkarni
- Department of Pediatric Cardiology Cohen Children’s Medical Center Zucker School of Medicine at Hofstra/Northwell New York NY USA
| | - Daisuke Morisawa
- Department of Biomedical Engineering University of California Irvine CA USA
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology University of California Irvine CA USA
| | - Daisy Gonzalez
- Division of Pediatric Cardiology Children’s Hospital at Montefiore New York NY USA
| | - Arash Kheradvar
- Department of Biomedical Engineering University of California Irvine CA USA
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology University of California Irvine CA USA
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8
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Ambrogio S, Walker A, Narracott A, Ferrari S, Verma P, Fenner J. A complex flow phantom for medical imaging: ring vortex phantom design and technical specification. J Med Eng Technol 2019; 43:190-201. [DOI: 10.1080/03091902.2019.1640309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Simone Ambrogio
- Department of Infection, Immunity and Cardiovascular Disease, Medical Physics, Mathematical Modelling in Medicine Group, University of Sheffield, Sheffield, UK
- Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
- Leeds Test Objects Ltd, Boroughbridge, UK
| | | | - Andrew Narracott
- Department of Infection, Immunity and Cardiovascular Disease, Medical Physics, Mathematical Modelling in Medicine Group, University of Sheffield, Sheffield, UK
- Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
| | - Simone Ferrari
- Department of Infection, Immunity and Cardiovascular Disease, Medical Physics, Mathematical Modelling in Medicine Group, University of Sheffield, Sheffield, UK
- Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
| | - Prashant Verma
- Medical Imaging and Medical Physics, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - John Fenner
- Department of Infection, Immunity and Cardiovascular Disease, Medical Physics, Mathematical Modelling in Medicine Group, University of Sheffield, Sheffield, UK
- Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
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9
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Post-operative ventricular flow dynamics following atrioventricular valve surgical and device therapies: A review. Med Eng Phys 2018; 54:1-13. [DOI: 10.1016/j.medengphy.2018.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/17/2017] [Accepted: 01/28/2018] [Indexed: 01/26/2023]
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10
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Pagel PS, Dye L, Boettcher BT, Freed JK. Advanced Age Attenuates Left Ventricular Filling Efficiency Quantified Using Vortex Formation Time: A Study of Octogenarians With Normal Left Ventricular Systolic Function Undergoing Coronary Artery Surgery. J Cardiothorac Vasc Anesth 2018. [PMID: 29525195 DOI: 10.1053/j.jvca.2018.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Blood flow across the mitral valve during early left ventricular (LV) filling produces a 3-dimensional rotational fluid body, known as a vortex ring, that enhances LV filling efficiency. Diastolic dysfunction is common in elderly patients, but the influence of advanced age on vortex formation is unknown. The authors tested the hypothesis that advanced age is associated with a reduction in LV filling efficiency quantified using vortex formation time (VFT) in octogenarians undergoing coronary artery bypass graft (CABG) surgery. DESIGN Observational study. SETTING Veterans Affairs medical center. PARTICIPANTS After institutional review board approval, octogenarians (n = 7; 82 ± 2 year [mean ± standard deviation]; ejection fraction 56% ± 7%) without valve disease or atrial arrhythmias undergoing CABG were compared with a younger cohort (n = 7; 55 ± 6 year; ejection fraction 57% ± 7%) who were undergoing coronary revascularization. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS All patients were monitored using radial and pulmonary arterial catheters and transesophageal echocardiography. 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, atrial filling fraction (β), and E wave deceleration time. Pulse-wave Doppler also was used to measure pulmonary venous blood flow during systole and diastole. Mitral valve diameter (D) was calculated as the average of major and minor axis lengths obtained in the midesophageal LV bicommissural and long-axis transesophageal echocardiography imaging planes, respectively. VFT was calculated as 4 × (1 - β) × SV/(πD3), where SV is the stroke volume measured using thermodilution. Systemic and pulmonary hemodynamics, LV diastolic function, and VFT were determined during steady-state conditions 30 minutes before cardiopulmonary bypass. A delayed relaxation pattern of LV filling (E/A 0.81 ± 0.16 v 1.29 ± 0.19, p = 0.00015; β 0.44 ± 0.05 v 0.35 ± 0.03, p = 0.0008; E wave deceleration time 294 ± 58 v 166 ± 28 ms, p < 0.0001; ratio of peak pulmonary venous systolic and diastolic blood flow velocity 1.42 ± 0.23 v 1.14 ± 0.20, p = 0.0255) was observed in octogenarians compared with younger patients. Mitral valve diameter was similar between groups (2.7 ± 0.2 and 2.6 ± 0.2 cm, respectively, in octogenarians v younger patients, p = 0.299). VFT was reduced in octogenarians compared with younger patients (3.0 ± 0.9 v 4.5 ± 1.2; p = 0.0171). An inverse correlation between age and VFT was shown using linear regression analysis (VFT = -0.0627 × age + 8.24; r2 = 0.408; p = 0.0139). CONCLUSION The results indicate that LV filling efficiency quantified using VFT is reduced in octogenarians compared with younger patients undergoing coronary artery bypass grafting.
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Affiliation(s)
- Paul S Pagel
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI.
| | - Lonnie Dye
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
| | - Brent T Boettcher
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
| | - Julie K Freed
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
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11
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Pagel PS, Boettcher BT, De Vry DJ, Freed JK, Iqbal Z. Moderate Aortic Valvular Insufficiency Invalidates Vortex Formation Time as an Index of Left Ventricular Filling Efficiency in Patients With Severe Degenerative Calcific Aortic Stenosis Undergoing Aortic Valve Replacement. J Cardiothorac Vasc Anesth 2016; 30:1260-5. [PMID: 27474333 DOI: 10.1053/j.jvca.2016.03.144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Transmitral blood flow produces a vortex ring (quantified using vortex formation time [VFT]) that enhances the efficiency of left ventricular (LV) filling. VFT is attenuated in LV hypertrophy resulting from aortic valve stenosis (AS) versus normal LV geometry. Many patients with AS also have aortic insufficiency (AI). The authors tested the hypothesis that moderate AI falsely elevates VFT by partially inhibiting mitral leaflet opening in patients with AS. DESIGN Observational study. SETTING Veterans Affairs medical center. PARTICIPANTS Patients with AS in the presence or absence of moderate AI (n = 8 per group) undergoing aortic valve replacement (AVR) were studied after institutional review board approval. 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 transesophageal echocardiography (TEE) to determine E/A and atrial filling fraction (beta). Mitral valve diameter (D) was calculated as the average of major and minor axis lengths obtained in the midesophageal bicommissural (transcommissural anterior-lateral-posterior medial) and LV long-axis (anterior-posterior) TEE imaging planes, respectively. VFT was calculated as 4·(1-beta)·SV/πD(3), where SV = stroke volume measured using thermodilution. Hemodynamics, diastolic function, and VFT were determined during steady-state conditions before cardiopulmonary bypass. The severity of AS (mean and peak pressure gradients, peak transvalvular jet velocity, aortic valve area) and diastolic function (E/A, beta) were similar between groups. Moderate centrally directed AI was present in 8 patients with AS (ratio of regurgitant jet width to LV outflow tract diameter of 36±6%). Pulse pressure and mean pulmonary artery pressure were elevated in patients with versus without AI, but no other differences in hemodynamics were observed. Mitral valve minor and major axis lengths, diameter, and area were reduced in the presence versus the absence of AI. VFT was increased significantly (5.7±1.7 v 3.2±0.6; p = 0.00108) in patients with AS and AI compared with AS alone. CONCLUSION Moderate AI falsely elevates VFT in patients with severe AS undergoing AVR by partially inhibiting mitral valve opening. VFT may be an unreliable index of LV filling efficiency with competitive diastolic flow into the LV.
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Affiliation(s)
- Paul S Pagel
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI.
| | - Brent T Boettcher
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
| | - Derek J De Vry
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
| | - Julie K Freed
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
| | - Zafar Iqbal
- Anesthesia Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
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12
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Su B, Tan RS, Tan JL, Guo KWQ, Zhang JM, Leng S, Zhao X, Allen JC, Zhong L. Cardiac MRI based numerical modeling of left ventricular fluid dynamics with mitral valve incorporated. J Biomech 2016; 49:1199-1205. [PMID: 26993615 DOI: 10.1016/j.jbiomech.2016.03.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 11/27/2022]
Abstract
Recent numerical studies were focused on the modeling of flow in patient-specific left ventricle (LV); however, the mitral valve (MV) was usually excluded. In this study, both patient-specific LV and MV were modeled to achieve a more realistic intraventricular flow. Cardiac MRI images were acquired from a pulmonary arterial hypertension (PAH) patient and a healthy volunteer, and manual segmentation was conducted to reconstruct three-dimensional (3D) LV and MV geometries at each frame. Based on these 3D geometries, vortex formation time (VFT) was derived, and the values were 4.0 and 6.5 for the normal subject and the PAH patient, respectively. Based on studies in the literature, VTF in the healthy subject fell within the normal range, while that in the PAH patient exceeded the threshold for normality. The vortex structures in the LV clearly showed that the vortex ring was initiated from the tips of the MV instead of the mitral annulus. The excessive VFT during the rapid filling phase in the PAH patient resulted in a trailing flow structure behind the primary vortex ring, which was not observed in the normal subject. It can be deduced from this study that incorporating the MV into a patient-specific model is necessary to produce more reasonable VFT and intraventricular flow.
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Affiliation(s)
- Boyang Su
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore
| | - Ru San Tan
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore; Duke-NUS Graduate Medical School Singapore, Singapore
| | - Ju Le Tan
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore
| | | | - Jun Mei Zhang
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore; Duke-NUS Graduate Medical School Singapore, Singapore
| | - Shuang Leng
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore
| | - Xiaodan Zhao
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore
| | | | - Liang Zhong
- National Heart Centre Singapore, 5 Hospital Drive, 169609, Singapore; Duke-NUS Graduate Medical School Singapore, Singapore.
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13
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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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14
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Gao H, Bijnens N, Coisne D, Lugiez M, Rutten M, D'hooge J. 2-D left ventricular flow estimation by combining speckle tracking with Navier-Stokes-based regularization: an in silico, in vitro and in vivo study. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:99-113. [PMID: 25438850 DOI: 10.1016/j.ultrasmedbio.2014.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 08/19/2014] [Accepted: 08/24/2014] [Indexed: 06/04/2023]
Abstract
Despite the availability of multiple ultrasound approaches to left ventricular (LV) flow characterization in two dimensions, this technique remains in its childhood and further developments seem warranted. This article describes a new methodology for tracking the 2-D LV flow field based on ultrasound data. Hereto, a standard speckle tracking algorithm was modified by using a dynamic kernel embedding Navier-Stokes-based regularization in an iterative manner. The performance of the proposed approach was first quantified in synthetic ultrasound data based on a computational fluid dynamics model of LV flow. Next, an experimental flow phantom setup mimicking the normal human heart was used for experimental validation by employing simultaneous optical particle image velocimetry as a standard reference technique. Finally, the applicability of the approach was tested in a clinical setting. On the basis of the simulated data, pointwise evaluation of the estimated velocity vectors correlated well (mean r = 0.84) with the computational fluid dynamics measurement. During the filling period of the left ventricle, the properties of the main vortex obtained from the proposed method were also measured, and their correlations with the reference measurement were also calculated (radius, r = 0.96; circulation, r = 0.85; weighted center, r = 0.81). In vitro results at 60 bpm during one cardiac cycle confirmed that the algorithm properly measures typical characteristics of the vortex (radius, r = 0.60; circulation, r = 0.81; weighted center, r = 0.92). Preliminary qualitative results on clinical data revealed physiologic flow fields.
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Affiliation(s)
- Hang Gao
- Lab on Cardiovascular Imaging and Dynamics, KU Leuven, Leuven, Belgium.
| | - Nathalie Bijnens
- Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Damien Coisne
- University Hospital of Poitiers-Hospital of La Miletrie, Poitiers, France
| | | | - Marcel Rutten
- Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jan D'hooge
- Lab on Cardiovascular Imaging and Dynamics, KU Leuven, Leuven, Belgium
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15
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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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16
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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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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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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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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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de Vecchi A, Nordsletten DA, Razavi R, Greil G, Smith NP. Patient specific fluid–structure ventricular modelling for integrated cardiac care. Med Biol Eng Comput 2013; 51:1261-70. [DOI: 10.1007/s11517-012-1030-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 12/30/2012] [Indexed: 11/24/2022]
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21
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de Vecchi A, Nordsletten DA, Remme EW, Bellsham-Revell H, Greil G, Simpson JM, Razavi R, Smith NP. Inflow Typology and Ventricular Geometry Determine Efficiency of Filling in the Hypoplastic Left Heart. Ann Thorac Surg 2012; 94:1562-9. [DOI: 10.1016/j.athoracsur.2012.05.122] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 05/30/2012] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
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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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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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24
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Pagel PS, Gandhi SD, Iqbal Z, Hudetz JA. Cardiopulmonary Bypass Transiently Inhibits Intraventricular Vortex Ring Formation in Patients Undergoing Coronary Artery Bypass Graft Surgery. J Cardiothorac Vasc Anesth 2012; 26:376-80. [DOI: 10.1053/j.jvca.2011.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Indexed: 11/11/2022]
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25
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Zhang H, Zhang J, Zhu X, Chen L, Liu L, Duan Y, Yu M, Zhou X, Zhu T, Zhu M, Li H. The left ventricular intracavitary vortex during the isovolumic contraction period as detected by vector flow mapping. Echocardiography 2012; 29:579-87. [PMID: 22324480 DOI: 10.1111/j.1540-8175.2011.01649.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIMS The purpose of this study was to characterize left ventricular (LV) intracavitary flow during the isovolumic contraction (IVC) period in humans using vector flow mapping. METHODS Color flow Doppler imaging was performed from the apical long-axis view in 61 patients with heart failure and 58 healthy volunteers. Doppler flow data obtained during IVC were analyzed offline with vector flow mapping. RESULTS A large vortex was formed from the LV inflow toward the outflow during IVC. In normal subjects, the area of the vortex was sustained, but the flow volume decreased significantly during IVC (P < 0.001). A significant apex-to-base flow velocity gradient was shown along the outflow axis on aortic valve opening. However, both the area and flow volume of the vortex decreased more severely during IVC in the patients (P < 0.001). The apex-to-base flow velocity gradient along the outflow axis disappeared and a reversed velocity gradient was observed at the basal-mid level on aortic valve opening. In multivariate models, a decreased LV ejection fraction was the only independent predictor of the percentage decrease in area of the vortex during the IVC (P < 0.001), and a larger QRS width (P = 0.028) and LV end-systolic long diameter (P = 0.002) were independent predictors of the percentage decrease in flow volume of the vortex. CONCLUSIONS The vortex across the LV inflow-outflow region during IVC facilitates the ejection of blood during early systole, and an unsustained vortex may be associated with impaired cardiac function.
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Affiliation(s)
- Haibin Zhang
- Department of Ultrasound, PLA 210th Hospital, Dalian, China
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26
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Assessment of Transmitral Vortex Formation in Patients with Diastolic Dysfunction. J Am Soc Echocardiogr 2012; 25:220-7. [DOI: 10.1016/j.echo.2011.10.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Indexed: 11/19/2022]
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27
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Poh KK, Lee LC, Shen L, Chong E, Tan YL, Chai P, Yeo TC, Wood MJ. Left ventricular fluid dynamics in heart failure: echocardiographic measurement and utilities of vortex formation time. Eur Heart J Cardiovasc Imaging 2011; 13:385-93. [DOI: 10.1093/ejechocard/jer288] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Characterization of Mitral Valve Annular Dynamics in the Beating Heart. Ann Biomed Eng 2011; 39:1690-702. [DOI: 10.1007/s10439-011-0272-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 02/04/2011] [Indexed: 11/25/2022]
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Sengupta SP, Sengupta PP, Narula J. Echocardiographic Investigations of Myocardial Function in Mitral Stenosis: Making Sense of the Echolalia. Cardiology 2011; 119:142-4. [DOI: 10.1159/000331404] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/29/2011] [Indexed: 11/19/2022]
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Jiamsripong P, Alharthi MS, Calleja AM, McMahon EM, Katayama M, Westerdale J, Milano M, Heys JJ, Mookadam F, Belohlavek M. Impact of pericardial adhesions on diastolic function as assessed by vortex formation time, a parameter of transmitral flow efficiency. Cardiovasc Ultrasound 2010; 8:42. [PMID: 20860826 PMCID: PMC2954860 DOI: 10.1186/1476-7120-8-42] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 09/22/2010] [Indexed: 01/07/2023] Open
Abstract
Background Pericardial adhesions are a pathophysiological marker of constrictive pericarditis (CP), which impairs cardiac filling by limiting the total cardiac volume compliance and diastolic filling function. We studied diastolic transmitral flow efficiency as a new parameter of filling function in a pericardial adhesion animal model. We hypothesized that vortex formation time (VFT), an index of optimal efficient diastolic transmitral flow, is altered by patchy pericardial-epicardial adhesions. Methods In 8 open-chest pigs, the heart was exposed while preserving the pericardium. We experimentally simulated early pericardial constriction and patchy adhesions by instilling instant glue into the pericardial space and using pericardial-epicardial stitches. We studied left ventricular (LV) function and characterized intraventricular blood flow with conventional and Doppler echocardiography at baseline and following the experimental intervention. Results Significant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. The mean VFT value decreased from 3.61 ± 0.47 to 2.26 ± 0.45 (P = 0.0002). Hemodynamic variables indicated the inhibiting effect of pericardial adhesion on both contraction (decrease in systolic blood pressure and +dP/dt decreased) and relaxation (decrease in the magnitude of -dP/dt and prolongation of Tau) function. Conclusion Patchy pericardial adhesions not only negatively impact LV mechanical functioning but the decrease of VFT from normal to suboptimal value suggests impairment of transmitral flow efficiency.
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Affiliation(s)
- Panupong Jiamsripong
- Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA
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Modeling radial viscoelastic behavior of left ventricle based on MRI tissue phase mapping. Ann Biomed Eng 2010; 38:3102-11. [PMID: 20505993 DOI: 10.1007/s10439-010-0079-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Accepted: 05/13/2010] [Indexed: 10/19/2022]
Abstract
The viscoelastic behavior of myocardial tissue is a measure that has recently found to be a deterministic factor in quality of contraction. Parameters imposing the viscoelastic behavior of the heart are influenced in part by sarcomere function and myocardial composition. Despite the overall agreement on significance of cardiac viscoelasticity, a practical model that can measure and characterize the viscoelastic behavior of the myocardial segments does not yet exist. Pressure-Volume (P-V) curves are currently the only measure for stiffness/compliance of the left ventricle. However, obtaining P-V curves requires invasive cardiac catheterization, and only provides qualitative information on how pressure and volume change with respect to each other. For accurate assessment of myocardial mechanical behavior, it is required to obtain quantitative measures for viscoelasticity. In this work, we have devised a model that yields myocardial elastic and viscous damping coefficient functions through the cardiac cycle. The required inputs for this model are kinematic information with respect to changes in LV short axes that were obtained by Magnetic Resonance Imaging (MRI) using a tissue phase mapping (TPM) pulse sequence. We evaluated viscoelastic coefficients of LV myocardium in two different age groups of 20-40 and greater than 60. We found that the magnitude of stiffness coefficients is noticeably greater in the older subjects. Additionally, we found that slope of viscous damping functions follow similar patterns for each individual age group. This method may shed light on dynamics of contraction through MRI in conditions where composition of myocardium is changed such as in aging, adverse remodeling, and cardiomyopathies.
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Kheradvar A, Houle H, Pedrizzetti G, Tonti G, Belcik T, Ashraf M, Lindner JR, Gharib M, Sahn D. Echocardiographic Particle Image Velocimetry: A Novel Technique for Quantification of Left Ventricular Blood Vorticity Pattern. J Am Soc Echocardiogr 2010; 23:86-94. [DOI: 10.1016/j.echo.2009.09.007] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Indexed: 11/29/2022]
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Belohlavek M, Jiamsripong P, Calleja AM, McMahon EM, Maarouf CL, Kokjohn TA, Chaffin TL, Vedders LJ, Garami Z, Beach TG, Sabbagh MN, Roher AE. Patients with Alzheimer disease have altered transmitral flow: echocardiographic analysis of the vortex formation time. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2009; 28:1493-1500. [PMID: 19854964 DOI: 10.7863/jum.2009.28.11.1493] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range. METHODS Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Association's criteria and 23 age-matched individuals as a control group with cognitive function within normal limits. RESULTS The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean +/- SD, 0.67 +/- 14) when compared with the control individuals (0.79 +/- 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end-diastolic diameter were significantly higher in the AD group (P <or= 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time-velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018). CONCLUSIONS Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with age-matched control individuals.
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Affiliation(s)
- Marek Belohlavek
- Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA
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Impact of acute moderate elevation in left ventricular afterload on diastolic transmitral flow efficiency: analysis by vortex formation time. J Am Soc Echocardiogr 2009; 22:427-31. [PMID: 19171461 DOI: 10.1016/j.echo.2008.12.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Indexed: 11/24/2022]
Abstract
BACKGROUND The formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. Vortex formation time (VFT) is an index of the optimal conditions for vortex formation. It was hypothesized that left ventricular (LV) afterload impairs diastolic transmitral flow efficiency and therefore shifts the VFT out of its optimal range. METHODS In 9 open-chest pigs, LV afterload was elevated by externally constricting the ascending aorta and increasing systolic blood pressure to 130% of baseline value for 3 minutes. RESULTS Systolic LV function decreased, diastolic filling velocity increased only during the late (atrial) phase from 0.46 +/- 0.06 to 0.63 +/- 0.19 m/s (P = .0231), and end-diastolic LV volume and heart rate remained unchanged. VFT decreased from 4.09 +/- 0.27 to 2.78 +/- 1.03 (P = .0046). CONCLUSION An acute, moderate elevation in LV afterload worsens conditions for diastolic vortex formation, suggesting impaired blood transport efficiency.
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Kheradvar A, Gharib M. On Mitral Valve Dynamics and its Connection to Early Diastolic Flow. Ann Biomed Eng 2008; 37:1-13. [DOI: 10.1007/s10439-008-9588-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 10/17/2008] [Indexed: 11/30/2022]
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Votta E, Caiani E, Veronesi F, Soncini M, Montevecchi FM, Redaelli A. Mitral valve finite-element modelling from ultrasound data: a pilot study for a new approach to understand mitral function and clinical scenarios. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2008; 366:3411-3434. [PMID: 18603525 DOI: 10.1098/rsta.2008.0095] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In the current scientific literature, particular attention is dedicated to the study of the mitral valve and to comprehension of the mechanisms that lead to its normal function, as well as those that trigger possible pathological conditions. One of the adopted approaches consists of computational modelling, which allows quantitative analysis of the mechanical behaviour of the valve by means of continuum mechanics theory and numerical techniques. However, none of the currently available models realistically accounts for all of the aspects that characterize the function of the mitral valve. Here, a new computational model of the mitral valve has been developed from in vivo data, as a first step towards the development of patient-specific models for the evaluation of annuloplasty procedures. A structural finite-element model of the mitral valve has been developed to account for all of the main valvular substructures. In particular, it includes the real geometry and the movement of the annulus and papillary muscles, reconstructed from four-dimensional ultrasound data from a healthy human subject, and a realistic description of the complex mechanical properties of mitral tissues. Preliminary simulations allowed mitral valve closure to be realistically mimicked and the role of annulus and papillary muscle dynamics to be quantified.
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Affiliation(s)
- Emiliano Votta
- Bioengineering Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
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Papillary muscle and annulus size effect on anterior and posterior annulus tension of the mitral valve: An insight into annulus dilatation. J Biomech 2008; 41:2524-32. [DOI: 10.1016/j.jbiomech.2008.05.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 05/01/2008] [Accepted: 05/06/2008] [Indexed: 11/22/2022]
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