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Bornemann KM, Jahren SE, Obrist D. The relation between aortic morphology and transcatheter aortic heart valve thrombosis: Particle tracing and platelet activation in larger aortic roots with and without neo-sinus. Comput Biol Med 2024; 179:108828. [PMID: 38996554 DOI: 10.1016/j.compbiomed.2024.108828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 06/05/2024] [Accepted: 06/29/2024] [Indexed: 07/14/2024]
Abstract
Transcatheter aortic heart valve thrombosis (THVT) affects long-term valve durability, transvalvular pressure gradient and leaflet mobility. In this study, we conduct high-fidelity fluid-structure interaction simulations to perform Lagrangian particle tracing in a generic model with larger aortic diameters (THVT model) with and without neo-sinus which is compared to a model of unaffected TAVI patients (control model). Platelet activation indices are computed for each particle to assess the risk of thrombus formation induced by high shear stresses followed by flow stagnation. Particle tracing indicates that fewer particles contribute to sinus washout of the THVT model with and without neo-sinus compared to the control model (-34.9%/-34.1%). Stagnating particles in the native sinus of the THVT model show higher platelet activation indices than for the control model (+39.6% without neo-sinus, +45.3% with neo-sinus). Highest activation indices are present for particles stagnating in the neo-sinus of the larger aorta representing THVT patients (+80.2% compared to control). This fluid-structure interaction (FSI) study suggests that larger aortas lead to less efficient sinus washout in combination with higher risk of platelet activation among stagnating particles, especially within the neo-sinus. This could explain (a) a higher occurrence of thrombus formation in transcatheter valves compared to surgical valves without neo-sinus and (b) the neo-sinus as the prevalent region for thrombi in TAV. Pre-procedural identification of larger aortic roots could contribute to better risk assessment of patients and improved selection of a patient-specific anti-coagulation therapy.
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Affiliation(s)
- Karoline-Marie Bornemann
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, Bern, 3010, Switzerland.
| | - Silje Ekroll Jahren
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, Bern, 3010, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, Bern, 3010, Switzerland
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2
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Racz AO, Szabo GT, Papp T, Csippa B, Gyurki D, Kracsko B, Koszegi Z, Kolozsvari R. Potential Clinical Usefulness of Post-Valvular Contrast Densities to Determine the Severity of Aortic Valve Stenosis Using Computed Tomography. J Cardiovasc Dev Dis 2023; 10:412. [PMID: 37887859 PMCID: PMC10607528 DOI: 10.3390/jcdd10100412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023] Open
Abstract
BACKGROUND Different methods are established for the changes in aortic valve stenosis with cardiac computed tomography angiography (CCTA), but the effect of the grade of stenosis on contrast densities around the valve has not been investigated. AIMS/METHODS Using the information from flow dynamics in cases of increased velocity through narrowed lumen, the hypothesis was formed that flow changes can alter the contrast densities in stenotic post-valvular regions, and the density changes might correlate with the grade of stenosis. Forty patients with severe aortic stenosis and fifteen with a normal aortic valve were enrolled. With echocardiography, the peak/mean transvalvular gradients, peak transvalvular velocity, and aortic valve opening area were obtained. With CCTA, densities 4-5 mm above the aortic valve; at the junction of the left, right, and noncoronary cusp to the annulus; at the middle level of the left, right, and noncoronary sinuses of Valsalva in the center and the lateral points; at the sinotubular junction; and 4 cm from the sinotubular junction at the midline were measured. First, a comparison of the densities between the normal and stenotic valve was performed, and then possible correlations between echocardiography and CCTA values were investigated in the stenotic group. RESULTS In all CCTA regions, significantly lower-density values were detected among stenotic valve patients compared to the normal aortic valve population. Additionally, in both groups, higher densities were measured in the peri-jet regions than in the lateral ones. Furthermore, a good correlation was found between the aortic valve opening area and the densities in almost all perivalvular areas. With regard to the densities at the junction of the non-coronary leaflet to the fibrotic annulus and at the most lateral point of the right sinus of Valsalva, a high level of correlation was found between all echocardiography and CCTA parameters. Lastly, with receiver operating characteristic curve measurements, area under the curve values were between 0.857 and 0.930. CONCLUSION Certain CCTA density values, especially 4-5mm above the valve opening, can serve as auxiliary information to echocardiography when the severity of aortic valve stenosis is unclear.
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Affiliation(s)
- Agnes Orsolya Racz
- Department of Cardiology and Heart Surgery, University of Debrecen, 4032 Debrecen, Hungary; (A.O.R.); (G.T.S.); (B.K.); (Z.K.)
| | - Gabor Tamas Szabo
- Department of Cardiology and Heart Surgery, University of Debrecen, 4032 Debrecen, Hungary; (A.O.R.); (G.T.S.); (B.K.); (Z.K.)
| | - Tamas Papp
- Department of Radiology, University of Debrecen, 4032 Debrecen, Hungary;
| | - Benjamin Csippa
- Department of Hydrodynamic Systems, University of Technology and Economics, 1111 Budapest, Hungary; (B.C.); (D.G.)
| | - Daniel Gyurki
- Department of Hydrodynamic Systems, University of Technology and Economics, 1111 Budapest, Hungary; (B.C.); (D.G.)
| | - Bertalan Kracsko
- Department of Cardiology and Heart Surgery, University of Debrecen, 4032 Debrecen, Hungary; (A.O.R.); (G.T.S.); (B.K.); (Z.K.)
| | - Zsolt Koszegi
- Department of Cardiology and Heart Surgery, University of Debrecen, 4032 Debrecen, Hungary; (A.O.R.); (G.T.S.); (B.K.); (Z.K.)
- 3rd Department of Internal Medicine, Szabolcs-Szatmar-Bereg County Hospital, 4400 Nyíregyháza, Hungary
| | - Rudolf Kolozsvari
- Department of Cardiology and Heart Surgery, University of Debrecen, 4032 Debrecen, Hungary; (A.O.R.); (G.T.S.); (B.K.); (Z.K.)
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Asadi H, Hedayat M, Borazjani I. The Effects of Implantation Orientation of a Bileaflet Mechanical Heart Valve in an Anatomic Left Ventricle-Aorta Configuration. J Biomech Eng 2022; 144:1140397. [PMID: 35466356 DOI: 10.1115/1.4054411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Indexed: 11/08/2022]
Abstract
We have performed three-dimensional high-resolution numerical simulations of a bi-leaflet mechanical heart valve (BMHV) implanted at different orientations in an anatomic left ventricle-aorta obtained from magnetic resonance imaging (MRI) of a volunteer. The thoroughly validated overset curvilinear-immersed boundary (overset-CURVIB) fluid-structure interaction (FSI) flow solver is used in which the aorta and LV are discretized with boundary-conforming and non-conforming curvilinear grids, respectively. The motion of the LV wall is prescribed based on a lumped parameter model while the motion of the leaflets are calculated using a strong coupled FSI algorithm enhanced with Aitken convergence technique. We carried out simulations for three valve orientations, which differ from each other by 45 degrees and compared the leaflet motion and flow field for multiple cycles. Our results show reproducible and relatively symmetrical opening for all valve orientations. The presence of small-scale vortical structures after peak systole, cause significant cycle-to-cycle variations in valve kinematics during the closing phase for all valve orientations. Furthermore, our results show that valve orientation does not have a significant effect on the distribution of viscous shear stress in the ascending aorta. Additionally, two different mathematical activation models including linear level of activation and Soares model are used to quantify the platelet activation in the ascending aorta. The results show that the valve orientation does not significantly affect (less than 8%) the total platelet activation in the ascending aorta.
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Affiliation(s)
- Hossein Asadi
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Mohammadali Hedayat
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Iman Borazjani
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843, USA
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Han D, Zhang J, Griffith BP, Wu ZJ. Models of Shear-Induced Platelet Activation and Numerical Implementation With Computational Fluid Dynamics Approaches. J Biomech Eng 2022; 144:1119644. [PMID: 34529037 DOI: 10.1115/1.4052460] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 12/17/2022]
Abstract
Shear-induced platelet activation is one of the critical outcomes when blood is exposed to elevated shear stress. Excessively activated platelets in the circulation can lead to thrombus formation and platelet consumption, resulting in serious adverse events such as thromboembolism and bleeding. While experimental observations reveal that it is related to the shear stress level and exposure time, the underlying mechanism of shear-induced platelet activation is not fully understood. Various models have been proposed to relate shear stress levels to platelet activation, yet most are modified from the empirically calibrated power-law model. Newly developed multiscale platelet models are tested as a promising approach to capture a single platelet's dynamic shape during activation, but it would be computationally expensive to employ it for a large-scale analysis. This paper summarizes the current numerical models used to study the shear-induced platelet activation and their computational applications in the risk assessment of a particular flow pattern and clot formation prediction.
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Affiliation(s)
- Dong Han
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201
| | - Bartley P Griffith
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201
| | - Zhongjun J Wu
- Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD 21201; Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD 20742
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5
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Computational Methods for Fluid-Structure Interaction Simulation of Heart Valves in Patient-Specific Left Heart Anatomies. FLUIDS 2022. [DOI: 10.3390/fluids7030094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Given the complexity of human left heart anatomy and valvular structures, the fluid–structure interaction (FSI) simulation of native and prosthetic valves poses a significant challenge for numerical methods. In this review, recent numerical advancements for both fluid and structural solvers for heart valves in patient-specific left hearts are systematically considered, emphasizing the numerical treatments of blood flow and valve surfaces, which are the most critical aspects for accurate simulations. Numerical methods for hemodynamics are considered under both the continuum and discrete (particle) approaches. The numerical treatments for the structural dynamics of aortic/mitral valves and FSI coupling methods between the solid Ωs and fluid domain Ωf are also reviewed. Future work toward more advanced patient-specific simulations is also discussed, including the fusion of high-fidelity simulation within vivo measurements and physics-based digital twining based on data analytics and machine learning techniques.
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6
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Soltany Sadrabadi M, Hedayat M, Borazjani I, Arzani A. Fluid-structure coupled biotransport processes in aortic valve disease. J Biomech 2021; 117:110239. [PMID: 33515904 DOI: 10.1016/j.jbiomech.2021.110239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/22/2020] [Accepted: 01/04/2021] [Indexed: 12/28/2022]
Abstract
Biological transport processes near the aortic valve play a crucial role in calcific aortic valve disease initiation and bioprosthetic aortic valve thrombosis. Hemodynamics coupled with the dynamics of the leaflets regulate these transport patterns. Herein, two-way coupled fluid-structure interaction (FSI) simulations of a 2D bicuspid aortic valve and a 3D mechanical heart valve were performed and coupled with various convective mass transport models that represent some of the transport processes in calcification and thrombosis. Namely, five different continuum transport models were developed to study biochemicals that originate from the blood and the leaflets, as well as residence-time and flow stagnation. Low-density lipoprotein (LDL) and platelet activation were studied for their role in calcification and thrombosis, respectively. Coherent structures were identified using vorticity and Lagrangian coherent structures (LCS) for the 2D and 3D models, respectively. A very close connection between vortex structures and biochemical concentration patterns was shown where different vortices controlled the concentration patterns depending on the transport mechanism. Additionally, the relationship between leaflet concentration and wall shear stress was revealed. Our work shows that blood flow physics and coherent structures regulate the flow-mediated biological processes that are involved in aortic valve calcification and thrombosis, and therefore could be used in the design process to optimize heart valve replacement durability.
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Affiliation(s)
| | - Mohammadali Hedayat
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Iman Borazjani
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA.
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Becsek B, Pietrasanta L, Obrist D. Turbulent Systolic Flow Downstream of a Bioprosthetic Aortic Valve: Velocity Spectra, Wall Shear Stresses, and Turbulent Dissipation Rates. Front Physiol 2020; 11:577188. [PMID: 33117194 PMCID: PMC7550765 DOI: 10.3389/fphys.2020.577188] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 08/25/2020] [Indexed: 12/02/2022] Open
Abstract
Every year, a quarter million patients receive prosthetic heart valves in aortic valve replacement therapy. Prosthetic heart valves are known to lead to turbulent blood flow. This turbulent flow field may have adverse effects on blood itself, on the aortic wall and on the valve performance. A detailed characterization of the turbulent flow downstream of a valve could yield better understanding of its effect on shear-induced thrombocyte activation, unphysiological wall shear stresses and hemodynamic valve performance. Therefore, computational simulations of the flow past a bioprosthetic heart valve were performed. The computational results were validated against experimental measurements of the turbulent flow field with tomographic particle image velocimetry. The turbulent flow was analyzed for disturbance amplitudes, dissipation rates and shear stress distributions. It was found that approximately 26% of the hydrodynamic resistance of the valve was due to turbulent dissipation and that this dissipation mainly took place in a region about one valve diameter downstream of the valve orifice. Farther downstream, the turbulent fluctuations became weaker which was also reflected in the turbulent velocity spectra of the flow field. Viscous shear stresses were found to be in the range of the critical level for blood platelet activation. The turbulent flow led to elevated shear stress levels along the wall of the ascending aorta with strongly fluctuating and chaotic wall shear stress patterns. Further, we identified leaflet fluttering at 40 Hz which was connected to repeated shedding of vortex rings that appeared to feed the turbulent flow downstream of the valve.
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Affiliation(s)
- Barna Becsek
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Leonardo Pietrasanta
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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8
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Johnson EL, Wu MCH, Xu F, Wiese NM, Rajanna MR, Herrema AJ, Ganapathysubramanian B, Hughes TJR, Sacks MS, Hsu MC. Thinner biological tissues induce leaflet flutter in aortic heart valve replacements. Proc Natl Acad Sci U S A 2020; 117:19007-19016. [PMID: 32709744 PMCID: PMC7431095 DOI: 10.1073/pnas.2002821117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Valvular heart disease has recently become an increasing public health concern due to the high prevalence of valve degeneration in aging populations. For patients with severely impacted aortic valves that require replacement, catheter-based bioprosthetic valve deployment offers a minimally invasive treatment option that eliminates many of the risks associated with surgical valve replacement. Although recent percutaneous device advancements have incorporated thinner, more flexible biological tissues to streamline safer deployment through catheters, the impact of such tissues in the complex, mechanically demanding, and highly dynamic valvular system remains poorly understood. The present work utilized a validated computational fluid-structure interaction approach to isolate the behavior of thinner, more compliant aortic valve tissues in a physiologically realistic system. This computational study identified and quantified significant leaflet flutter induced by the use of thinner tissues that initiated blood flow disturbances and oscillatory leaflet strains. The aortic flow and valvular dynamics associated with these thinner valvular tissues have not been previously identified and provide essential information that can significantly advance fundamental knowledge about the cardiac system and support future medical device innovation. Considering the risks associated with such observed flutter phenomena, including blood damage and accelerated leaflet deterioration, this study demonstrates the potentially serious impact of introducing thinner, more flexible tissues into the cardiac system.
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Affiliation(s)
- Emily L Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Michael C H Wu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Fei Xu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Nelson M Wiese
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Manoj R Rajanna
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | - Austin J Herrema
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
| | | | - Thomas J R Hughes
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712;
| | - Michael S Sacks
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712;
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011;
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9
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Hedayat M, Patel TR, Kim T, Belohlavek M, Hoffmann KR, Borazjani I. A hybrid echocardiography-CFD framework for ventricular flow simulations. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e03352. [PMID: 32419374 DOI: 10.1002/cnm.3352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/05/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Image-based CFD is a powerful tool to study cardiovascular flows while 2D echocardiography (echo) is the most widely used noninvasive imaging modality for the diagnosis of heart disease. Here, echo is combined with CFD, that is, an echo-CFD framework, to study ventricular flows. To achieve this, the previous 3D reconstruction from multiple 2D echo at standard cross sections is extended by: (a) reconstructing aortic and mitral valves from 2D echo and closing the left-ventricle (LV) geometry by approximating a superior wall; (b) incorporating the physiological assumption of the fixed apex as a reference (fixed) point in the 3D reconstruction; and (c) incorporating several smoothing algorithms to remove the nonphysical oscillations (ringing) near the basal section. The method is applied to echo from a baseline LV and one after inducing acute myocardial ischemia (AMI). The 3D reconstruction is validated by comparing it against a reference reconstruction from many echo sections while flow simulations are validated against the Doppler ultrasound velocity measurements. The sensitivity study shows that the choice of the smoothing algorithm does not change the flow pattern inside the LV. However, the presence of the mitral valve can significantly change the flow pattern during the diastole phase. In addition, the abnormal shape of a LV with AMI can drastically change the flow during diastole. Furthermore, the hemodynamic energy loss, as an indicator of the LV pumping performance, for different test cases is calculated, which shows a larger energy loss for a LV with AMI compared to the baseline one.
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Affiliation(s)
- Mohammadali Hedayat
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas, USA
| | - Tatsat R Patel
- Department of Mechanical and Aerospace Engineering, State University of New York at Buffalo, Buffalo, New York, USA
| | - Taeouk Kim
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas, USA
| | - Marek Belohlavek
- Department of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA
| | - Kenneth R Hoffmann
- Department of Neurosurgery, University at Buffalo SUNY, Buffalo, New York, USA
| | - Iman Borazjani
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas, USA
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Abstract
Copepods are small aquatic creatures which are abundant in oceans as a major food source for fish, thereby playing a vital role in marine ecology. Because of their role in the food chain, copepods have been subject to intense research through different perspectives from anatomy, form-function biology, to ecology. Numerical simulations can uniquely support such investigations by quantifying: (i) the force and flow generated by different parts of the body, thereby clarify the form-function relation of each part; (ii) the relation between the small-scale flow around animal and the large-scale (e.g., oceanic) flow of its surroundings; and (iii) the flow and its energetics, thereby answering ecological questions, particularly, the three major survival tasks, i.e., feeding, predator avoidance, and mate-finding. Nevertheless, such numerical simulations need to overcome challenges involving complex anatomic shape of copepods, multiple moving appendages, resolving different scales (appendage-, animal- to large-scale). The numerical methods capable of handling such problems and some recent simulations are reviewed. At the end, future developments necessary to simulate copepods from animal- to surrounding-scale are discussed.
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Hirschhorn M, Tchantchaleishvili V, Stevens R, Rossano J, Throckmorton A. Fluid–structure interaction modeling in cardiovascular medicine – A systematic review 2017–2019. Med Eng Phys 2020; 78:1-13. [DOI: 10.1016/j.medengphy.2020.01.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 01/18/2020] [Accepted: 01/26/2020] [Indexed: 01/06/2023]
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Sadipour M, Hanafizadeh P, Sadeghy K, Sattari A. Effect of Aortic Wall Deformation with Healthy and Calcified Annulus on Hemodynamic Performance of Implanted On-X Valve. Cardiovasc Eng Technol 2020; 11:141-161. [PMID: 31912432 DOI: 10.1007/s13239-019-00453-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/24/2019] [Indexed: 11/27/2022]
Abstract
INTRODUCTION In this research, the hemodynamic performance of a 23-mm On-X bileaflet mechanical heart valve (BMHV) was investigated with the realistic geometry model of the valve and the deformable aorta in accelerating systole. In addition, the effect of ascending aorta flexibility and aortic annulus calcification on the complex blood flow characteristics were investigated. METHODS The geometry of the aorta is derived from the medical images, and the Ogden model has been utilized for the mechanical behavior of the ascending aorta. The 3D numerical simulation by a two-way Fluid-Structure Interaction (FSI) analysis using the Arbitrary Lagrangian-Eulerian (ALE) method was performed throughout the accelerating systolic phase. RESULTS The dynamics of the leaflets are investigated, and blood flow characteristics such as velocities, vorticities as well as viscous and turbulent shear stress were precisely captured in the flow domain specifically in the hinge region. Streamline results are in accordance with the previously reported data, which show that the flared On-X valves inlet yields a more uniform flow in accelerating systole. Simulations show that aorta flexibility or valve annulus calcification causes variations up to 7% in maximum fluid velocity and 20% in Turbulence Kinetic Energy (TKE). CONCLUSIONS In this study, the complex flow field characteristics in the new generation of BMHVs considering aorta flexibility with healthy and calcified annulus were investigated. It was found that the blood flow around the hinges region is in the danger of hemolysis and platelet activation and subsequently thromboembolism. Furthermore, the results show that similar to vessel wall deformation, considering the probable annulus calcification after valve replacement is also essential.
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Affiliation(s)
- Masod Sadipour
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Pedram Hanafizadeh
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
| | - Keyvan Sadeghy
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Amirmohammad Sattari
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
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13
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Hosseini HS, Taylor JS, Wood LS, Dunn JC. Biomechanics of small intestine during distraction enterogenesis with an intraluminal spring. J Mech Behav Biomed Mater 2020; 101:103413. [DOI: 10.1016/j.jmbbm.2019.103413] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/13/2019] [Accepted: 08/31/2019] [Indexed: 12/25/2022]
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14
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Mirvakili N, Di Labbio G, Saleh W, Kadem L. Flow characteristics in a model of a left ventricle in the presence of a dysfunctional mitral mechanical heart valve. J Vis (Tokyo) 2019. [DOI: 10.1007/s12650-019-00611-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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15
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Abbas SS, Nasif MS, Al-Waked R, Meor Said MA. Numerical investigation on the effect of bileaflet mechanical heart valve's implantation tilting angle and aortic root geometry on intermittent regurgitation and platelet activation. Artif Organs 2019; 44:E20-E39. [PMID: 31378963 DOI: 10.1111/aor.13536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/27/2019] [Accepted: 07/03/2019] [Indexed: 11/27/2022]
Abstract
Platelet activation induced by shear stresses and non-physiological flow field generated by bileaflet mechanical heart valves (BMHVs) leads to thromboembolism, which can cause fatal consequences. One of the causes of platelet activation could be intermittent regurgitation, which arises due to asynchronous movement and rebound of BMHV leaflets during the valve closing phase. In this numerical study, the effect of intermittent regurgitation on the platelet activation potential of BMHVs was quantified by modeling a BMHV in the straight and anatomic aorta at implantation tilt angles 0°, 5°, 10°, and 20°. A fully implicit Arbitrary Lagrangian-Eulerian-based Fluid-Structure Interaction formulation was adopted with blood modeled as a multiphase, non-Newtonian fluid. Results showed that the intermittent regurgitation and consequently the platelet activation level increases with the increasing implantation tilt of BMHV. For the straight aorta, the leaflet of the 20° tilted BMHV underwent a rebound of approximately 20° after initially closing, whereas the leaflet of the 10°, 5°, and 0° tilted BMHVs underwent a rebound of 8.5°, 3°, and 0°, respectively. For the anatomic aorta, the leaflet of the 20° tilted BMHV underwent a rebound of approximately 24° after initially closing, whereas the leaflet of the 10°, 5°, and 0° tilted BMHVs underwent a rebound of 14°, 10°, and 7°, respectively. For all the implantation orientations of BMHVs, intermittent regurgitation and platelet activation were always higher in the anatomic aorta than in the straight aorta. The study concludes that the pivot axis of BMHV must be implanted parallel to the aortic root's curvature to minimize intermittent regurgitation and platelet activation.
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Affiliation(s)
- Syed Samar Abbas
- Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia
| | - Mohammad Shakir Nasif
- Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia
| | - Rafat Al-Waked
- Department of Mechanical and Maintenance Engineering, German Jordanian University, Amman, Jordan
| | - Mior Azman Meor Said
- Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia
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Darwish A, Di Labbio G, Saleh W, Smadi O, Kadem L. Experimental investigation of the flow downstream of a dysfunctional bileaflet mechanical aortic valve. Artif Organs 2019; 43:E249-E263. [DOI: 10.1111/aor.13483] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/26/2019] [Accepted: 04/29/2019] [Indexed: 01/08/2023]
Affiliation(s)
- Ahmed Darwish
- Laboratory of Cardiovascular Fluid Dynamics, Mechanical, Industrial and Aerospace Engineering Concordia University Montreal Quebec Canada
| | - Giuseppe Di Labbio
- Laboratory of Cardiovascular Fluid Dynamics, Mechanical, Industrial and Aerospace Engineering Concordia University Montreal Quebec Canada
| | - Wael Saleh
- Laboratory of Cardiovascular Fluid Dynamics, Mechanical, Industrial and Aerospace Engineering Concordia University Montreal Quebec Canada
| | - Othman Smadi
- Department of Biomedical Engineering Hashemite University Zarqa Jordan
| | - Lyes Kadem
- Laboratory of Cardiovascular Fluid Dynamics, Mechanical, Industrial and Aerospace Engineering Concordia University Montreal Quebec Canada
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17
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Lei L, Tao X, Xie L, Hong Z. Vascular endothelial growth factor-loaded elastin-hydrogel modification of the pericardium improves endothelialization potential of bioprosthetic heart valves. J Biomater Appl 2019; 34:451-459. [PMID: 31195917 DOI: 10.1177/0885328219854336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Lang Lei
- The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xin Tao
- The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Lifeng Xie
- The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Zhengdong Hong
- The Second Affiliated Hospital of Nanchang University, Nanchang, China
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18
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Lei Y, Deng L, Tang Y, Ning Q, Lan X, Wang Y. Hybrid Pericardium with VEGF‐Loaded Hyaluronic Acid Hydrogel Coating to Improve the Biological Properties of Bioprosthetic Heart Valves. Macromol Biosci 2019; 19:e1800390. [DOI: 10.1002/mabi.201800390] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 03/19/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Yang Lei
- National Engineering Research Center for BiomaterialsSichuan University Chengdu 610064 China
| | - Lu Deng
- National Engineering Research Center for BiomaterialsSichuan University Chengdu 610064 China
| | - Yuyang Tang
- National Engineering Research Center for BiomaterialsSichuan University Chengdu 610064 China
| | - Qinggong Ning
- National Engineering Research Center for BiomaterialsSichuan University Chengdu 610064 China
| | - Xiaorong Lan
- National Engineering Research Center for BiomaterialsSichuan University Chengdu 610064 China
| | - Yunbing Wang
- National Engineering Research Center for BiomaterialsSichuan University Chengdu 610064 China
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19
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Lei Y, Ning Q, Tang Y, Wang Y. Exogenous hyaluronic acid and chondroitin sulfate crosslinking treatment for increasing the amount and stability of glycosaminoglycans in bioprosthetic heart valves. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2019; 30:38. [PMID: 30840150 DOI: 10.1007/s10856-019-6237-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
Glutaraldehyde (GLUT) crosslinked bioprosthetic heart valves (BHVs) might fail due to progressive degradation and calcification. GLUT cannot stabilize glycosaminoglycans (GAGs), which are important for BHVs' life time. In this current study we developed a new BHVs preparation strategy using exogenous hyaluronic acid (HA)/chondroitin sulfate (CS) supplement and sodium trimetaphosphate (STP) crosslinking method. Exogenous HA and CS provide additional GAGs for pericardiums. STP could link two GAGs by reacting with hydroxyl groups in GAGs' repeating polysaccharides units. The feeding ratios of HA/CS were optimized. The GAGs content and long-term stability in vitro, biocompatibility, the in vivo GAGs stability and anti-calcification potential of GLUT/HA/CS and STP treated pericardiums were characterized. We demonstrated that GLUT/HA/CS and STP treated pericardiums had sufficiently increased GAGs' amount and stability and decreased calcification. This new exogenous hyaluronic acid/chondroitin sulfate supplement and sodium trimetaphosphate crosslinking strategy would be a promising method to make BHVs with better structural stability and anti-calcification properties.
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Affiliation(s)
- Yang Lei
- National Engineering Research Center for Biomaterials, Sichuan University, 610064, Chengdu, China.
| | - Qinggong Ning
- National Engineering Research Center for Biomaterials, Sichuan University, 610064, Chengdu, China
| | - Yuyang Tang
- National Engineering Research Center for Biomaterials, Sichuan University, 610064, Chengdu, China
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials, Sichuan University, 610064, Chengdu, China.
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20
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Asgharzadeh H, Borazjani I. A non-dimensional parameter for classification of the flow in intracranial aneurysms. I. Simplified geometries. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2019; 31:031904. [PMID: 30967744 PMCID: PMC6435374 DOI: 10.1063/1.5033942] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 07/04/2018] [Indexed: 05/21/2023]
Abstract
Non-dimensional parameters are routinely used to classify different flow regimes. We propose a non-dimensional parameter, called Aneurysm number (An), which depends on both geometric and flow characteristics, to classify the flow inside aneurysm-like geometries (sidewalls and bifurcations). The flow inside aneurysm-like geometries can be widely classified into (i) the vortex mode in which a vortex ring is formed and (ii) the cavity mode in which a stationary shear layer acts similar to a moving lid of a lid-driven cavity. In these modes, two competing time scales exist: (a) a transport time scale, T t , which is the time scale to develop a shear layer by transporting a fluid particle across the expansion region, and (b) the vortex formation time scale,T v . Consequently, a relevant non-dimensional parameter is the ratio of these two time scales, which is called Aneurysm number: An = T t /T v . It is hypothesized, based on this definition, that the flow is in the vortex mode if the time required for vortex ring formationT v is less than the transport time T t (An ≳ 1). Otherwise, the flow is in the cavity mode (An ≲ 1). This hypothesis is systematically tested through numerical simulations on simplified geometries and shown to be true through flow visualizations and identification of the main vortex and shear layer. The main vortex is shown to evolve when An ≳ 1 but stationary when An ≲ 1. In fact, it is shown that the flows with An ≲ 1 (cavity mode) are characterized by much smaller fluctuations of wall shear stress and oscillatory shear index relative to flows with An ≳ 1 (vortex mode) because of their quasi-stationary flow pattern (cavity mode) compared to the evolution and breakdown of the formed vortex ring (vortex mode).
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Affiliation(s)
- Hafez Asgharzadeh
- Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
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21
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Lei Y, Ning Q, Xia Y, Wang Y. Enzyme-oxidative-polymerization method for improving glycosaminoglycans stability and reducing calcification in bioprosthetic heart valves. Biomed Mater 2019; 14:025012. [DOI: 10.1088/1748-605x/aafd7c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Lei Y, Guo G, Jin W, Liu M, Wang Y. Riboflavin photo‐cross‐linking method for improving elastin stability and reducing calcification in bioprosthetic heart valves. Xenotransplantation 2019; 26:e12481. [DOI: 10.1111/xen.12481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/30/2018] [Accepted: 12/07/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Yang Lei
- National Engineering Research Center for Biomaterials Sichuan University Chengdu China
| | - Gaoyang Guo
- National Engineering Research Center for Biomaterials Sichuan University Chengdu China
| | - Wanyu Jin
- National Engineering Research Center for Biomaterials Sichuan University Chengdu China
| | - Mengwei Liu
- National Engineering Research Center for Biomaterials Sichuan University Chengdu China
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials Sichuan University Chengdu China
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23
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Hedayat M, Borazjani I. Comparison of platelet activation through hinge vs bulk flow in bileaflet mechanical heart valves. J Biomech 2019; 83:280-290. [DOI: 10.1016/j.jbiomech.2018.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 11/12/2018] [Accepted: 12/03/2018] [Indexed: 10/27/2022]
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24
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Lei Y, Xia Y, Wang Y. The tropoelastin and lysyl oxidase treatments increased the content of insoluble elastin in bioprosthetic heart valves. J Biomater Appl 2018; 33:637-646. [DOI: 10.1177/0885328218807077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Valvular heart diseases lead to over 300,000 heart valve replacements worldwide each year. Commercially available bioprosthetic heart valves (BHVs) are mostly made from porcine or bovine pericardiums which were crosslinked by glutaraldehyde (GLUT). However, valve failures can occur within 10 years due to progressive degradation and calcification. GLUT could crosslink collagen but it fails to stabilize elastin. In this current study, we developed a new BHVs preparation strategy named as “GLUT/TE/LOXL/EGCG” that utilizes exogenous tropoelastin (TE)/lysyl oxidase (LOXL) and epigallocatechin gallate (EGCG) to increase the elastin content as well as the stabilization of elastin. The feeding ratios of tropoelastin and lysyl oxidase were optimized. The contents of desmosine and insoluble elastin, biomechanics, cytotoxicity, hemocompatibility, in vivo componential stability and anti-calcification potential were characterized. Pericardiums with increased elastin content had improved the mechanical properties. GLUT/TE/LOXL/EGCG-treated pericardiums had similar cytotoxicity and coagulation properties compared to GLUT and GLUT/EGCG control. We demonstrated that GLUT/TE/LOXL/EGCG-treated pericardiums had high amount of insoluble elastin in 90 days’ rat subdermal implantation model, and better resistance for calcification. This new tropoelastin and lysyl oxidase treatments strategy would be a promising method to make BHVs which have better structural stability and anti-calcification properties.
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Affiliation(s)
- Yang Lei
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China
| | - Yushun Xia
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China
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25
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Lei Y, Yang L, Guo G, Wang Y. EGCG and enzymatic cross-linking combined treatments for improving elastin stability and reducing calcification in bioprosthetic heart valves. J Biomed Mater Res B Appl Biomater 2018; 107:1551-1559. [PMID: 30267643 DOI: 10.1002/jbm.b.34247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/20/2018] [Accepted: 08/31/2018] [Indexed: 11/10/2022]
Abstract
The failures of glutaraldehyde (GLUT) cross-linked bioprosthetic heart valves (BHVs) are mainly due to degeneration and calcification. In this study, we developed a new preparation strategy for BHVs named as "HPA/EDC/EGCG" that utilized 3,4-hydroxyphenylpropionic acid (HPA)-conjugated pericardium, epigallocatechin gallate (EGCG), and horseradish peroxidase (HRP)/hydrogen peroxide (H2 O2 ) enzymatic cross-linking. HPA-pericardium conjugation was done by carbodiimide coupling reaction using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Then HPA-conjugated pericardium was cross-linked by HRP/H2 O2 enzyme-catalyzed oxidation. The feeding ratios of HPA and EGCG were optimized. The consumption of amino groups, collagenase and elastase degradation in vitro, biomechanics, extracellular matrix stability, and calcification of HPA-/EDC-/EGCG-treated pericardiums were characterized. We demonstrated that HPA-/EDC-/EGCG-treated pericardiums had better elastin stabilization and less calcification. EGCG and enzymatic cross-linking treated pericardiums showed improved mechanical properties. This new EGCG and enzymatic cross-linking strategy would be a promising method to make BHVs with better elastin stability and anti-calcification property. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1551-1559, 2019.
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Affiliation(s)
- Yang Lei
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, China
| | - Li Yang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, China
| | - Gaoyang Guo
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, China
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, China
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26
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Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study. FLUIDS 2018. [DOI: 10.3390/fluids3030056] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
(1) The study’s objective is to assess sinus hemodynamics differences between stenotic native bicuspid aortic valve (BAV) and native tricuspid aortic valve (TrAV) sinuses in order to assess sinus flow shear and vorticity dynamics in these common pathological states of the aortic valve. (2) Representative patient-specific aortic roots with BAV and TrAV were selected, segmented, and 3D printed. The flow dynamics within the sinus were assessed in-vitro using particle image velocimetry in a left heart simulator at physiological pressure and flow conditions. Hemodynamic data calculations, vortex tracking, shear stress probability density functions and sinus washout calculations based on Lagrangian particle tracking were performed. (3) (a) At peak systole, velocity and vorticity in BAV reach 0.67 ± 0.02 m/s and 374 ± 5 s−1 versus 0.49 ± 0.03 m/s and 293 ± 3 s−1 in TrAV; (b) Aortic sinus vortex is slower to form but conserved in BAV sinus; (c) BAV shear stresses exceed those of TrAV (1.05 Pa versus 0.8 Pa); (d) Complete TrAV washout was achieved after 1.5 cycles while it was not for BAV. 4) In conclusion, sinus hemodynamics dependence on the different native aortic valve types and sinus morphologies was clearly highlighted in this study.
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27
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Hasler D, Obrist D. Three-dimensional flow structures past a bio-prosthetic valve in an in-vitro model of the aortic root. PLoS One 2018; 13:e0194384. [PMID: 29547668 PMCID: PMC5856406 DOI: 10.1371/journal.pone.0194384] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 03/04/2018] [Indexed: 12/18/2022] Open
Abstract
The flow field past a prosthetic aortic valve comprises many details that indicate whether the prosthesis is functioning well or not. It is, however, not yet fully understood how an optimal flow scenario would look, i.e. which subtleties of the fluid dynamics in place are essential regarding the durability and compatibility of a prosthetic valve. In this study, we measured and analyzed the 3D flow field in the vicinity of a bio-prosthetic heart valve in function of the aortic root size. The measurements were conducted within aortic root phantoms of different size, mounted in a custom-built hydraulic setup, which mimicked physiological flow conditions in the aorta. Tomographic particle image velocimetry was used to measure the 3D instantaneous velocity field at various instances. Several 3D fields (e.g. instantaneous and mean velocity, 3D shear rate) were analyzed and compared focusing on the impact of the aortic root size, but also in order to gain general insight in the 3D flow structure past the bio-prosthetic valve. We found that the diameter of the aortic jet relative to the diameter of the ascending aorta is the most important parameter in determining the characteristics of the flow. A large aortic cross-section, relative to the cross-section of the aortic jet, was associated with higher levels of turbulence intensity and higher retrograde flow in the ascending aorta.
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Affiliation(s)
- David Hasler
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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28
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Experimental Assessment of Flow Fields Associated with Heart Valve Prostheses Using Particle Image Velocimetry (PIV): Recommendations for Best Practices. Cardiovasc Eng Technol 2018. [DOI: 10.1007/s13239-018-0348-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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29
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Hosseinzadegan H, Tafti DK. Modeling thrombus formation and growth. Biotechnol Bioeng 2017; 114:2154-2172. [DOI: 10.1002/bit.26343] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/03/2017] [Accepted: 05/16/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Hamid Hosseinzadegan
- Mechanical Engineering DepartmentVirginia Polytechnic Institute and State University, 213E Goodwin Hall ‐ 0238, 635 Prices Fork RoadBlacksburgVirginia24061
| | - Danesh K. Tafti
- Mechanical Engineering DepartmentVirginia Polytechnic Institute and State University, 213E Goodwin Hall ‐ 0238, 635 Prices Fork RoadBlacksburgVirginia24061
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30
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Hydrodynamic Simulation of an Orbital Shaking Test for the Degradation Assessment of Blood-Contact Biomedical Coatings. MICROMACHINES 2017. [PMCID: PMC6189871 DOI: 10.3390/mi8040132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Biomedical coatings are used to promote the wear resistance and the biocompatibility of a mechanical heart valve. An orbital shaking test was proposed to assess the durability of the coatings by the amount material eroded by the surrounding fluid. However, there is still a lack of understanding with regards to the shaker’s rotating conditions and the corresponding physiological condition. This study implemented numerical simulations by establishing a fluid dynamic model to evaluate the intensity of the shear stress under various rotating speeds and diameters of the shaker. The results are valuable to conduct in vitro tests for estimating the performance of biomedical coatings under real hemodynamic conditions and can be applied to other fluid-contact implants.
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