1
|
Meng K, Chen H, Pan Y, Li Y. The dynamics of red blood cells traversing slits of mechanical heart valves under high shear. Biophys J 2024:S0006-3495(24)00654-4. [PMID: 39340153 DOI: 10.1016/j.bpj.2024.09.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 09/04/2024] [Accepted: 09/25/2024] [Indexed: 09/30/2024] Open
Abstract
Hemolysis, including subclinical hemolysis, is a potentially severe complications of mechanical heart valves (MHVs), which leads to shortened red blood cell (RBC) lifespan and hemolytic anemia. Serious hemolysis is usually associated with structural deterioration and regurgitation. However, the shear stress in MHVs' narrow leakage slits is much lower than the shear stress threshold causing hemolysis and the mechanisms in this context remain largely unclear. This study investigated the hemolysis mechanism of RBCs in cell-size slits under high shear rates by establishing in vitro microfluidic devices and a coarse-grained molecular dynamics (CGMD) model, considering both fluid and structural effects simultaneously. Microfluidic experiments and computational simulation revealed six distinct dynamic states of RBC traversal through MHVs' microscale slits under various shear rates and slit sizes. It elucidated that RBC dynamic states were influenced by not only by fluid forces but significantly by the compressive force of slit walls. The variation of the potential energy of the cell membrane indicated its stretching, deformation, and rupture during traversal, corresponding to the six dynamic states. The maximum forces exerted on membrane by water particles and slit walls directly determined membrane rupture, serving as a critical determinant. This analysis helps in understanding the contribution of the slit walls to membrane rupture and identifying the threshold force that leads to membrane rupture. The hemolysis mechanism of traversing microscale slits is revealed to effectively explain the occurrences of hemolysis and subclinical hemolysis.
Collapse
Affiliation(s)
- Kuilin Meng
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Haosheng Chen
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Yunfan Pan
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Yongjian Li
- State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, China.
| |
Collapse
|
2
|
Chen A, Basri AAB, Ismail NB, Tamagawa M, Zhu D, Ahmad KA. Simulation of Mechanical Heart Valve Dysfunction and the Non-Newtonian Blood Model Approach. Appl Bionics Biomech 2022; 2022:9612296. [PMID: 35498142 PMCID: PMC9042627 DOI: 10.1155/2022/9612296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 11/17/2022] Open
Abstract
The mechanical heart valve (MHV) is commonly used for the treatment of cardiovascular diseases. Nonphysiological hemodynamic in the MHV may cause hemolysis, platelet activation, and an increased risk of thromboembolism. Thromboembolism may cause severe complications and valve dysfunction. This paper thoroughly reviewed the simulation of physical quantities (velocity distribution, vortex formation, and shear stress) in healthy and dysfunctional MHV and reviewed the non-Newtonian blood flow characteristics in MHV. In the MHV numerical study, the dysfunction will affect the simulation results, increase the pressure gradient and shear stress, and change the blood flow patterns, increasing the risks of hemolysis and platelet activation. The blood flow passes downstream and has obvious recirculation and stagnation region with the increased dysfunction severity. Due to the complex structure of the MHV, the non-Newtonian shear-thinning viscosity blood characteristics become apparent in MHV simulations. The comparative study between Newtonian and non-Newtonian always shows the difference. The shear-thinning blood viscosity model is the basics to build the blood, also the blood exhibiting viscoelastic properties. More details are needed to establish a complete and more realistic simulation.
Collapse
Affiliation(s)
- Aolin Chen
- Faculty of Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Adi Azriff Bin Basri
- Faculty of Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Norzian Bin Ismail
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Masaaki Tamagawa
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Fukuoka 804-8550, Japan
| | - Di Zhu
- Faculty of Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| | - Kamarul Arifin Ahmad
- Faculty of Engineering, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia
| |
Collapse
|
3
|
Pietrasanta L, Zheng S, De Marinis D, Hasler D, Obrist D. Characterization of Turbulent Flow Behind a Transcatheter Aortic Valve in Different Implantation Positions. Front Cardiovasc Med 2022; 8:804565. [PMID: 35097022 PMCID: PMC8794584 DOI: 10.3389/fcvm.2021.804565] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/14/2021] [Indexed: 11/21/2022] Open
Abstract
The development of turbulence after transcatheter aortic valve (TAV) implantation may have detrimental effects on the long-term performance and durability of the valves. The characterization of turbulent flow generated after TAV implantation can provide fundamental insights to enhance implantation techniques. A self-expandable TAV was tested in a pulse replicator and the three-dimensional flow field was extracted by means of tomographic particle image velocimetry. The valve was fixed inside a silicone phantom mimicking the aortic root and the flow field was studied for two different supra-annular axial positions at peak systole. Fluctuating velocities and turbulent kinetic energy were compared between the two implantations. Velocity spectra were derived at different spatial positions in the turbulent wakes to characterize the turbulent flow. The valve presented similar overall flow topology but approximately 8% higher turbulent intensity in the lower implantation. In this configuration, axial views of the valve revealed smaller opening area and more corrugated leaflets during systole, as well as more accentuated pinwheeling during diastole. The difference arose from a lower degree of expansion of the TAV's stent inside the aortic lumen. These results suggest that the degree of expansion of the TAV in-situ is related to the onset of turbulence and that a smaller and less regular opening area might introduce flow instabilities that could be detrimental for the long-term performance of the valve. The present study highlights how implantation mismatches may affect the structure and intensity of the turbulent flow in the aortic root.
Collapse
Affiliation(s)
- Leonardo Pietrasanta
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- *Correspondence: Leonardo Pietrasanta
| | - Shaokai Zheng
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Dario De Marinis
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Dipartimento di Meccanica Matematica e Management, Centro di Eccellenza in Meccanica Computazionale, Politecnico di Bari, Bari, Italy
| | - 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
| |
Collapse
|
4
|
Dillinger H, McGrath C, Guenthner C, Kozerke S. Fundamentals of turbulent flow spectrum imaging. Magn Reson Med 2021; 87:1231-1249. [PMID: 34786764 PMCID: PMC9299145 DOI: 10.1002/mrm.29001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 08/12/2021] [Accepted: 08/18/2021] [Indexed: 12/13/2022]
Abstract
PURPOSE To introduce a mathematical framework and in-silico validation of turbulent flow spectrum imaging (TFSI) of stenotic flow using phase-contrast MRI, evaluate systematic errors in quantitative turbulence parameter estimation, and propose a novel method for probing the Lagrangian velocity spectra of turbulent flows. THEORY AND METHODS The spectral response of velocity-encoding gradients is derived theoretically and linked to turbulence parameter estimation including the velocity autocorrelation function spectrum. Using a phase-contrast MRI simulation framework, the encoding properties of bipolar gradient waveforms with identical first gradient moments but different duration are investigated on turbulent flow data of defined characteristics as derived from computational fluid dynamics. Based on theoretical insights, an approach using velocity-compensated gradient waveforms is proposed to specifically probe desired ranges of the velocity autocorrelation function spectrum with increased accuracy. RESULTS Practical velocity-encoding gradients exhibit limited encoding power of typical turbulent flow spectra, resulting in up to 50% systematic underestimation of intravoxel SD values. Depending on the turbulence level in fluids, the error due to a single encoding gradient spectral response can vary by 20%. When using tailored velocity-compensated gradients, improved quantification of the Lagrangian velocity spectrum on a voxel-by-voxel basis is achieved and used for quantitative correction of intravoxel SD values estimated with velocity-encoding gradients. CONCLUSION To address systematic underestimation of turbulence parameters using bipolar velocity-encoding gradients in phase-contrast MRI of stenotic flows with short correlation times, tailored velocity-compensated gradients are proposed to improve quantitative mapping of turbulent blood flow characteristics.
Collapse
Affiliation(s)
- Hannes Dillinger
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Charles McGrath
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Christian Guenthner
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| |
Collapse
|
5
|
Hemolysis estimation in turbulent flow for the FDA critical path initiative centrifugal blood pump. Biomech Model Mechanobiol 2021; 20:1709-1722. [PMID: 34106362 DOI: 10.1007/s10237-021-01471-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 05/28/2021] [Indexed: 02/08/2023]
Abstract
Hemolysis in medical devices and implants has been a primary concern over the past fifty years. Turbulent flow in particular can cause cell trauma and hemolysis in such devices. In this work, the effects of turbulence on red blood cell (RBC) damage are examined by simulating the flow field through a centrifugal blood pump that has been identified as a case study through the critical path initiative of the US Food and Drug Administration (FDA). In this study, a new model was employed to predict hemolysis in the turbulent flow environment in the pump selected for the FDA critical path initiative. The operating conditions for a centrifugal blood pump were specified by the FDA for rotational speeds of 2500 and 3500 rpm. The model is based on the analysis of the smaller eddies within the turbulent flow field, since it is assumed that turbulent flow eddies with sizes comparable to the dimensions of the RBCs lead to cell trauma. The Kolmogorov length scale of the velocity field is used to identify such small eddies. Using model parameters obtained in prior work through comparisons to capillary and jet flow, it is found that hemolysis for the 2500-rpm pump was predicted well, while hemolysis for the 3500-rpm pump was overpredicted. Results indicate refinement of the model and empirical constants with better experimental data is needed.
Collapse
|
6
|
Konnigk L, Torner B, Bruschewski M, Grundmann S, Wurm FH. Equivalent Scalar Stress Formulation Taking into Account Non-Resolved Turbulent Scales. Cardiovasc Eng Technol 2021; 12:251-272. [PMID: 33675019 PMCID: PMC8169507 DOI: 10.1007/s13239-021-00526-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 02/09/2021] [Indexed: 01/01/2023]
Abstract
PURPOSE Cardiovascular engineering includes flows with fluid-dynamical stresses as a parameter of interest. Mechanical stresses are high-risk factors for blood damage and can be assessed by computational fluid dynamics. By now, it is not described how to calculate an adequate scalar stress out of turbulent flow regimes when the whole share of turbulence is not resolved by the simulation method and how this impacts the stress calculation. METHODS We conducted direct numerical simulations (DNS) of test cases (a turbulent channel flow and the FDA nozzle) in order to access all scales of flow movement. After validation of both DNS with literature und experimental data using magnetic resonance imaging, the mechanical stress is calculated as a baseline. Afterwards, same flows are calculated using state-of-the-art turbulence models. The stresses are computed for every result using our definition of an equivalent scalar stress, which includes the influence from respective turbulence model, by using the parameter dissipation. Afterwards, the results are compared with the baseline data. RESULTS The results show a good agreement regarding the computed stress. Even when no turbulence is resolved by the simulation method, the results agree well with DNS data. When the influence of non-resolved motion is neglected in the stress calculation, it is underpredicted in all cases. CONCLUSION With the used scalar stress formulation, it is possible to include information about the turbulence of the flow into the mechanical stress calculation even when the used simulation method does not resolve any turbulence.
Collapse
Affiliation(s)
- Lucas Konnigk
- Institute of Turbomachinery, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany.
| | - Benjamin Torner
- Institute of Turbomachinery, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany
| | - Martin Bruschewski
- Institute of Fluid Mechanics, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany
| | - Sven Grundmann
- Institute of Fluid Mechanics, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany
| | - Frank-Hendrik Wurm
- Institute of Turbomachinery, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany
| |
Collapse
|
7
|
Lemétayer J, Broman LM, Prahl Wittberg L. Flow Dynamics and Mixing in Extracorporeal Support: A Study of the Return Cannula. Front Bioeng Biotechnol 2021; 9:630568. [PMID: 33644022 PMCID: PMC7902508 DOI: 10.3389/fbioe.2021.630568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/04/2021] [Indexed: 11/13/2022] Open
Abstract
Cannulation strategies in medical treatment such as in extracorporeal life support along with the associated cannula position, orientation and design, affects the mixing and the mechanical shear stress appearing in the flow field. This in turn influences platelet activation state and blood cell destruction. In this study, a co-flowing confined jet similar to a return cannula flow configuration found in extracorporeal membrane oxygenation was investigated experimentally. Cannula diameters, flow rate ratios between the jet and the co-flow and cannula position were studied using Particle Image Velocimetry and Planar Laser Induced Fluorescence. The jet was turbulent for all but two cases, in which a transitional regime was observed. The mixing, governed by flow entrainment, shear layer induced vortices and a backflow along the vessel wall, was found to require 9–12 cannula diameters to reach a fully homogeneous mixture. This can be compared to the 22–30 cannula diameters needed to obtain a fully developed flow. Although not significantly affecting mixing characteristics, cannula position altered the development of the flow structures, and hence the shear stress characteristics.
Collapse
Affiliation(s)
- Julien Lemétayer
- FLOW & BioMEx, Department of Engineering Mechanics, Royal Institute of Technology (KTH), Stockholm, Sweden
| | - L Mikael Broman
- ECMO Centre Karolinska, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Lisa Prahl Wittberg
- FLOW & BioMEx, Department of Engineering Mechanics, Royal Institute of Technology (KTH), Stockholm, Sweden
| |
Collapse
|
8
|
Hatoum H, Vallabhuneni S, Kota AK, Bark DL, Popat KC, Dasi LP. Impact of superhydrophobicity on the fluid dynamics of a bileaflet mechanical heart valve. J Mech Behav Biomed Mater 2020; 110:103895. [PMID: 32957201 PMCID: PMC11046437 DOI: 10.1016/j.jmbbm.2020.103895] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 05/13/2020] [Accepted: 05/30/2020] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The objective of this study is to evaluate the impact of superhydrophobic coating on the hemodynamics and turbulence characteristics of a bileaflet mechanical valve in the context of evaluating blood damage potential. METHODS Two 3D printed bileaflet mechanical valves were hemodynamically tested in a pulse duplicator under physiological pressure and flow conditions. The leaflets of one of the two valves were sprayed with a superhydrophobic coating. Particle Image Velocimetry was performed. Pressure gradients (PG), effective orifice areas (EOA), Reynolds shear stresses (RSS) and instantaneous viscous shear stresses (VSS) were calculated. RESULTS (a) Without SH coating, the PG was found to be 14.53 ± 0.7 mmHg and EOA 1.44 ± 0.06 cm2. With coating, the PG obtained was 15.21 ± 1.7 mmHg and EOA 1.39 ± 0.07 cm2; (b) during peak systole, the magnitude of RSS with SH coating (110Pa) exceeded that obtained without SH coating (40 Pa) with higher probabilities to develop higher RSS in the immediate wake of the leaflet; (c) The magnitudes range of instantaneous VSS obtained with SH coating were slightly larger than those obtained without SH coating (7.0 Pa versus 5.0 Pa). CONCLUSION With Reynolds Shear Stresses and instantaneous Viscous Shear Stresses being correlated with platelet damage, SH coating did not lead to their decrease. While SH coating is known to improve surface properties such as reduced platelet or clot adhesion, the relaxation of the slip condition does not necessarily improve overall hemodynamic performance for the bileaflet mechanical valve design.
Collapse
Affiliation(s)
- Hoda Hatoum
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Sravanthi Vallabhuneni
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Arun Kumar Kota
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - David L Bark
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Ketul C Popat
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Hemodynamic Performance of Dysfunctional Prosthetic Heart Valve with the Concomitant Presence of Subaortic Stenosis: In Silico Study. Bioengineering (Basel) 2020; 7:bioengineering7030090. [PMID: 32784661 PMCID: PMC7552677 DOI: 10.3390/bioengineering7030090] [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: 06/04/2020] [Revised: 07/29/2020] [Accepted: 08/06/2020] [Indexed: 01/09/2023] Open
Abstract
The prosthetic heart valve is vulnerable to dysfunction after surgery, thus a frequent assessment is required. Doppler electrocardiography and its quantitative parameters are commonly used to assess the performance of the prosthetic heart valves and provide detailed information on the interaction between the heart chambers and related prosthetic valves, allowing early detection of complications. However, in the case of the presence of subaortic stenosis, the accuracy of Doppler has not been fully investigated in previous studies and guidelines. Therefore, it is important to evaluate the accuracy of the parameters in such cases to get early detection, and a proper treatment plan for the patient, at the right time. In the current study, a CFD simulation was performed for the blood flow through a Bileaflet Mechanical Heart Valve (BMHV) with concomitant obstruction in the Left Ventricle Outflow Tract (LVOT). The current study explores the impact of the presence of the subaortic on flow patterns. It also investigates the accuracy of (BMHV) evaluation using Doppler parameters, as proposed in the American Society of Echocardiography (ASE) guidelines.
Collapse
|
11
|
Tarasev M, Chakraborty S, Light L, Alfano K, Pagani F. Red blood cell mechanical fragility as potential metric for assessing blood damage caused by implantable durable ventricular assist devices: Comparison of two types of centrifugal flow left ventricular assist devices. PROGRESS IN PEDIATRIC CARDIOLOGY 2020. [DOI: 10.1016/j.ppedcard.2020.101198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
12
|
Hatoum H, Girault E, Heim F, Dasi LP. In-vitro characterization of self-expandable textile transcatheter aortic valves. J Mech Behav Biomed Mater 2020; 103:103559. [PMID: 31786509 PMCID: PMC11107174 DOI: 10.1016/j.jmbbm.2019.103559] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 11/10/2019] [Accepted: 11/25/2019] [Indexed: 12/29/2022]
Abstract
OBJECTIVE This study aims at assessing the global dynamic behavior, closing energy and turbulence characteristics of self-expandable textile (inclined and straight yarn) transcatheter aortic valves (TAV) versus bioprosthetic TAVs. METHODS Two self-expandable textile TAVs one with inclined yarn textile and another with straight yarn textile leaflets were assessed in a pulse duplicator and compared with a self-expandable commercial bioprosthetic TAV under physiological pressure and flow. Particle Image Velocimetry and high-speed imaging were performed. Effective orifice areas (EOA), leakage fractions (LF), Pinwheeling indices (PI), closing energy (E), viscous shear stresses (VSS) and Reynolds shear stresses (RSS) were calculated. RESULTS (a) EOAs and LFs were 2.27 ± 0.03 cm2, 31.7 ± 0.6%; 2.25 ± 0.08 cm2, 26.6 ± 0.7%; and 1.63 ± 0.01 cm2, 29.1 ± 1.25% for inclined textile, bioprosthetic and straight textile TAV respectively (p < 0.0001). (b) Following same order, PIs were significantly different going from 1.16 ± 0.21%, 8.48 ± 0.8% and 8.865 ± 0.58% with the exception of CoreValve and straight yarn valve (p = 0.37); (c) E is lowest for straight textile TAV (0.0024 ± 0.0017 J), followed by bioprosthetic valve (0.00259 ± 0.0011 J) and then 45° Oriented Yarn Valve (0.00334 ± 0.03 J) (d) At peak systole, the highest RSS distribution was with the Straight textile TAV reaching up to 330Pa. The bioprosthetic TAV shows the smallest range with RSS reaching around 230Pa and the inclined textile TAV up to 280Pa. VSS limits were comparable among the 3 valves ranging between 5.2Pa and 5.7Pa. CONCLUSION Hemodynamic similarities were found between the textile self-expandable valves and the bioprosthetic valve. This study constitutes another step towards showing the potential that textile valves have to become an alternative for the biological ones.
Collapse
Affiliation(s)
- Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Elise Girault
- Laboratoire de Physique et Mécanique Textiles, Université de Haute Alsace, Mulhouse, France
| | - Frederic Heim
- Laboratoire de Physique et Mécanique Textiles, Université de Haute Alsace, Mulhouse, France
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States.
| |
Collapse
|
13
|
Gilmanov A, Stolarski H, Sotiropoulos F. Flow-Structure Interaction Simulations of the Aortic Heart Valve at Physiologic Conditions: The Role of Tissue Constitutive Model. J Biomech Eng 2019; 140:2668580. [PMID: 29305610 DOI: 10.1115/1.4038885] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 01/04/2023]
Abstract
The blood flow patterns in the region around the aortic valve depend on the geometry of the aorta and on the complex flow-structure interaction between the pulsatile flow and the valve leaflets. Consequently, the flow depends strongly on the constitutive properties of the tissue, which can be expected to vary between healthy and diseased heart valves or native and prosthetic valves. The main goal of this work is to qualitatively demonstrate that the choice of the constitutive model of the aortic valve is critical in analysis of heart hemodynamics. To accomplish that two different constitutive models were used in curvilinear immersed boundary-finite element-fluid-structure interaction (CURVIB-FE-FSI) method developed by Gilmanov et al. (2015, "A Numerical Approach for Simulating Fluid Structure Interaction of Flexible Thin Shells Undergoing Arbitrarily Large Deformations in Complex Domains," J. Comput. Phys., 300, pp. 814-843.) to simulate an aortic valve in an anatomic aorta at physiologic conditions. The two constitutive models are: (1) the Saint-Venant (StV) model and (2) the modified May-Newman&Yin (MNY) model. The MNY model is more general and includes nonlinear, anisotropic effects. It is appropriate to model the behavior of both prosthetic and biological tissue including native valves. Both models are employed to carry out FSI simulations of the same valve in the same aorta anatomy. The computed results reveal dramatic differences in both the vorticity dynamics in the aortic sinus and the wall shear-stress patterns on the aortic valve leaflets and underscore the importance of tissue constitutive models for clinically relevant simulations of aortic valves.
Collapse
Affiliation(s)
- Anvar Gilmanov
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414 e-mail:
| | - Henryk Stolarski
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, MN 55414 e-mail:
| | - Fotis Sotiropoulos
- College of Engineering and Applied Sciences, Stony Brook University, Stony Brook, NY 11794-2200 e-mail:
| |
Collapse
|
14
|
Gülan U, Appa H, Corso P, Templin C, Bezuidenhout D, Zilla P, Duru F, Holzner M. Performance analysis of the transcatheter aortic valve implantation on blood flow hemodynamics: An optical imaging‐based in vitro study. Artif Organs 2019; 43:E282-E293. [DOI: 10.1111/aor.13504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/11/2019] [Accepted: 05/23/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Utku Gülan
- Institute for Environmental Engineering Swiss Federal Institute of Technology Zurich Zurich Switzerland
| | - Harish Appa
- Strait Access Technologies University of Cape Town Observatory South Africa
| | - Pascal Corso
- Institute for Environmental Engineering Swiss Federal Institute of Technology Zurich Zurich Switzerland
| | | | - Deon Bezuidenhout
- Strait Access Technologies University of Cape Town Observatory South Africa
- Cardiovascular Research Unit University of Cape Town Observatory South Africa
| | - Peter Zilla
- Strait Access Technologies University of Cape Town Observatory South Africa
- Cardiovascular Research Unit University of Cape Town Observatory South Africa
| | - Firat Duru
- Department of Cardiology University Heart Center Zurich Switzerland
- Center for Integrative Human Physiology University of Zurich Zurich Switzerland
| | - Markus Holzner
- Institute for Environmental Engineering Swiss Federal Institute of Technology Zurich Zurich Switzerland
| |
Collapse
|
15
|
Heitkemper M, Hatoum H, Dasi LP. In vitro hemodynamic assessment of a novel polymeric transcatheter aortic valve. J Mech Behav Biomed Mater 2019; 98:163-171. [PMID: 31238208 DOI: 10.1016/j.jmbbm.2019.06.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 06/06/2019] [Accepted: 06/17/2019] [Indexed: 01/12/2023]
Abstract
Transcatheter aortic valve replacement (TAVR) is a life-saving alternative to surgical intervention. However, the identification of features associated with poor outcomes, including residual paravalvular leakage (PVL), leaflet calcification, and subclinical leaflet thrombosis, are cause to be concerned about valve durablilty (Mylotte and Piazza, 2015a, 2015b; Dasi et al., 2017; Makkar et al., 2015; Kheradvar et al., 2015a). The aim of this study is to optimize the potential of a hyaluronan (HA) enhanced polymeric transcatheter aortic valve (HA-TAV) that has promised to reduce blood damage causing-turbulent flow while maintaining durability. HA-enhanced linear low-density polyethylene (LLDPE) leaflets were sutured to novel cobalt chromium stents, size 26 mm balloon expandable stents. Hemodynamic performance was assessed in a left heart simulator under physiological pressure and flow conditions and compared to a 26 mm Medtronic Evolut and 26 mm Edwards SAPIEN 3. High-speed imaging and particle image velocimetry (PIV) were performed. The HA-TAV demonstrated an effective orifice area (EOA) within one standard deviation of the leading valve, SAPIEN 3.The regurgitant fraction (RF) of the HA-TAV (11.23 ± 0.55%) is decreased in comparison the Evolut (15.74 ± 0.73%) and slightly higher than the SAPIEN 3 (10.92 ± 0.11%), which is considered trace regurgitation according to valve standards. A decreased number of higher principal Reynolds shear stresses were shown for the HA-TAV at each cardiac phase. The HA-TAV is directly comparable and in some cases superior to the leading commercially available prosthetic heart valves in in-vitro hemodynamic testing.
Collapse
Affiliation(s)
- Megan Heitkemper
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA; Department of Mechanical Engineering, The Ohio State University, Columbus, OH, USA
| | - Lakshmi Prasad Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
| |
Collapse
|
16
|
Faghih MM, Sharp MK. Modeling and prediction of flow-induced hemolysis: a review. Biomech Model Mechanobiol 2019; 18:845-881. [DOI: 10.1007/s10237-019-01137-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 02/26/2019] [Indexed: 01/30/2023]
|
17
|
Faghih MM, Sharp MK. Evaluation of energy dissipation rate as a predictor of mechanical blood damage. Artif Organs 2019; 43:666-676. [DOI: 10.1111/aor.13418] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 11/15/2018] [Accepted: 12/10/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Mohammad M. Faghih
- Biofluid Mechanics Laboratory, Department of Mechanical Engineering University of Louisville Louisville Kentucky
| | - Michael Keith Sharp
- Biofluid Mechanics Laboratory, Department of Mechanical Engineering University of Louisville Louisville Kentucky
| |
Collapse
|
18
|
Use of Computational Fluid Dynamics to Analyze Blood Flow, Hemolysis and Sublethal Damage to Red Blood Cells in a Bileaflet Artificial Heart Valve. FLUIDS 2019. [DOI: 10.3390/fluids4010019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Artificial heart valves may expose blood to flow conditions that lead to unnaturally high stress and damage to blood cells as well as issues with thrombosis. The purpose of this research was to predict the trauma caused to red blood cells (RBCs), including hemolysis, from the stresses applied to them and their exposure time as determined by analysis of simulation results for blood flow through both a functioning and malfunctioning bileaflet artificial heart valve. The calculations provided the spatial distribution of the Kolmogorov length scales that were used to estimate the spatial and size distributions of the smallest turbulent flow eddies in the flow field. The number and surface area of these eddies in the blood were utilized to predict the amount of hemolysis experienced by RBCs. Results indicated that hemolysis levels are low while suggesting stresses at the leading edge of the leaflet may contribute to subhemolytic damage characterized by shortened circulatory lifetimes and reduced RBC deformability.
Collapse
|
19
|
Jhun CS, Stauffer MA, Reibson JD, Yeager EE, Newswanger RK, Taylor JO, Manning KB, Weiss WJ, Rosenberg G. Determination of Reynolds Shear Stress Level for Hemolysis. ASAIO J 2018; 64:63-69. [PMID: 28661910 DOI: 10.1097/mat.0000000000000615] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Reynolds shear stress (RSS) has served as a metric for the effect of turbulence on hemolysis. Forstrom (1969) and Sallam and Hwang (1984) determined the RSS threshold for hemolysis to be 50,000 and 4,000 dyne/cm, respectively, using a turbulent jet. Despite the order of magnitude discrepancy, the threshold by Sallam and Hwang has been frequently cited for hemolytic potential in blood pumps. We recreated a Sallam apparatus (SA) to resolve this discrepancy and provide additional data to be used in developing a more accurate hemolysis model. Hemolysis was measured over a large range of Reynolds numbers (Re) (Re = 1,000-80,000). Washed bovine red blood cells (RBCs) were injected into the free jet of phosphate buffered saline, and hemolysis was quantified using a percent hemolysis, Hp = h (100 - hematocrit [HCT])/Hb, where h (mg/dl) is free hemoglobin and Hb (mg/dl) is total hemoglobin. Reynolds shear stress was calculated using two-dimensional laser Doppler velocimetry. Reynolds shear stress of ≥30,000 dyne/cm corresponding to Re of ≥60,000 appeared to cause hemolysis (p < 0.05). This RSS is an order of magnitude greater than the RSS threshold that Sallam and Hwang suggested, and it is similar to Forstrom's RSS threshold. This study resolved a long-standing uncertainty regarding the critical values of RSS for hemolysis and may provide a foundation for a more accurate hemolysis model.
Collapse
|
20
|
Stented valve dynamic behavior induced by polyester fiber leaflet material in transcatheter aortic valve devices. J Mech Behav Biomed Mater 2018; 86:232-239. [PMID: 29986298 DOI: 10.1016/j.jmbbm.2018.06.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/21/2018] [Accepted: 06/25/2018] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study aims at assessing the global dynamic behavior, elastic deformability, closing energy and turbulence of rigid versus deformable stented (RS vs DS) valve systems with deformable and rigid textile materials (DT vs RT) through studying the stent-valve interaction compared to a bioprosthetic material in transcatheter aortic valves (TAV). METHODS Three 19 mm stented textile TAV designs (RS-DT, RS-RT and DS-RT) with different stent and leaflet properties were tested and compared with a control bioprosthetic TAV (RS-DB) in a left heart simulator flow loop under physiological pressure and flow. Particle Image Velocimetry and high speed imaging were performed. Pressure gradients (PG), leakage fractions (LF), Pinwheeling indices (PI), closing energy (E) and Reynolds shear stresses (RSS) were calculated. RESULTS (a) PGs and LFs were 11.86 ± 0.51 mmHg, 11.70 ± 0.34%; 8.84 ± 0.40 mmHg, 29.80 ± 0.76%; 11.59 ± 0.12 mmHg, 14.23 ± 1.64%; and 7.05 ± 0.09 mmHg, 12.08 ± 0.45% % for RS-DB, RS-DT, RS-RT and DS-RT respectively. (b) PIs were 15.79 ± 2.34%, 4.36 ± 0.84%, 2.47 ± 0.51% and 2.03 ± 0.33% for RS-DB, RS-DT, RS-RT and DS-RT respectively. (c) E is lowest for DS-RT (0.0010 ± 0.0002 J) followed by RS-RT (0.0017 ± 0.0002 J), RS-DB (0.0023 ± 0.0004 J) and highest with RS-DT (0.0036 ± 0.0007 J). (d) At peak systole lowest RSS was obtained with RS-DT (87.82 ± 0.58 Pa) and highest with DS-RT (122.98 ± 1.87 Pa). CONCLUSION PGs, LFs, PIs and E were improved with DS-RT compared to other textile TAVs and RS-DB. Despite achieving more RSS than the rest of TAVs, DS-RT still falls within the same range of RSS produced by the other 2 valves and control exceeding the threshold for platelet activation.
Collapse
|
21
|
Hatoum H, Yousefi A, Lilly S, Maureira P, Crestanello J, Dasi LP. An in vitro evaluation of turbulence after transcatheter aortic valve implantation. J Thorac Cardiovasc Surg 2018; 156:1837-1848. [PMID: 29961588 DOI: 10.1016/j.jtcvs.2018.05.042] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 04/17/2018] [Accepted: 05/13/2018] [Indexed: 01/20/2023]
Abstract
BACKGROUND This study aimed at assessment of post-transcatheter aortic valve (TAV) replacement hemodynamics and turbulence when a same-size SAPIEN 3 (Edwards Lifesciences Corp, Irvine, Calif) and Medtronic Evolut (Minneapolis, Minn) were implanted in a rigid aortic root with physiological dimensions and in a representative root with calcific leaflets obtained from patient computed tomography scans. METHODS TAV hemodynamics were studied by placing a SAPIEN 3 26-mm and an Evolut 26-mm in rigid aortic roots and representative root with calcific leaflets under physiological conditions. Hemodynamics were assessed using high-fidelity particle image velocimetry and high-speed imaging. Transvalvular pressure gradients (PGs), pinwheeling indices, and Reynolds shear stress (RSS) were calculated. RESULTS (1) PGs obtained with the Evolut and the SAPIEN 3 were comparable among the different models (10.5 ± 0.15 mm Hg vs 7.76 ± 0.083 mm Hg in the rigid model along with 13.9 ± 0.19 mm Hg vs 5.0 ± 0.09 mm Hg in representative root with calcific leaflets obtained from patient computed tomography scans respectively); (2) more pinwheeling was found in the SAPIEN 3 than the Evolut (0.231 ± 0.057 vs 0.201 ± 0.05 in the representative root with calcific leaflets and 0.366 ± 0.067 vs 0.122 ± 0.045 in the rigid model); (3) higher rates of RSS were found in the Evolut (161.27 ± 3.45 vs 122.84 ± 1.76 Pa in representative root with calcific leaflets and 337.22 ± 7.05 vs 157.91 ± 1.80 Pa in rigid models). More lateral fluctuations were found in representative root with calcific leaflets. CONCLUSIONS (1) Comparable PGs were found among the TAVs in different models; (2) pinwheeling indices were found to be different between both TAVs; (3) turbulence patterns among both TAVs translated according to RSS were different. Rigid aortic models yield more conservative estimates of turbulence; (4) both TAVs exhibit peak maximal RSS that exceeds platelet activation 100 Pa threshold limit.
Collapse
Affiliation(s)
- Hoda Hatoum
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Atieh Yousefi
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Scott Lilly
- Department of Surgery, The Ohio State University, Columbus, Ohio
| | - Pablo Maureira
- Department of Cardiovascular Surgery, CHU de Nancy, Nancy, France
| | - Juan Crestanello
- Department of Surgery, The Ohio State University, Columbus, Ohio
| | - Lakshmi P Dasi
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio; Department of Surgery, The Ohio State University, Columbus, Ohio.
| |
Collapse
|
22
|
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]
|
23
|
Kooistra NHM, Krings GJ, Stella PR, Voskuil M. Percutaneous closure of a combined ventricular septal defect and paravalvular regurgitation after transcatheter aortic valve implantation: case report. EUROPEAN HEART JOURNAL-CASE REPORTS 2018; 2:yty013. [PMID: 31020094 PMCID: PMC6426108 DOI: 10.1093/ehjcr/yty013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/09/2018] [Indexed: 11/13/2022]
Abstract
Introduction Transcatheter aortic valve implantation (TAVI) is a well-accepted alternative treatment for intermediate or high-risk patients with symptomatic severe native aortic valve stenosis. As the use of TAVI increases, there is a continuous growing insight into in the technical possibilities of the procedure and a parallel decrease in complications. A serious but rare complication of TAVI is a ventricular septal defect (VSD). Case presentation We report a case of a 90-year-old woman who underwent an uncomplicated TAVI procedure. She was readmitted within 2 weeks because of dyspnoea and oedema in the legs caused by acute left- and right-sided heart failure. Echocardiography showed a VSD of 1 cm, and mild to moderate paravalvular aortic regurgitation (PAR). Discussion This is the first report in which post-TAVI both a VSD and PAR are successfully repaired via a single percutaneous procedure.
Collapse
Affiliation(s)
- Nynke H M Kooistra
- Department of Cardiology, University Medical Center Utrecht, PO box: HP E.04.210, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands
| | - Gregor J Krings
- Department of Cardiology, University Medical Center Utrecht, PO box: HP E.04.210, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands
| | - Pieter R Stella
- Department of Cardiology, University Medical Center Utrecht, PO box: HP E.04.210, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands
| | - Michiel Voskuil
- Department of Cardiology, University Medical Center Utrecht, PO box: HP E.04.210, Heidelberglaan 100, 3508 GA Utrecht, The Netherlands
| |
Collapse
|
24
|
Kaminsky R, Morbiducci U, Rossi M, Scalise L, Verdonck P, Grigioni M. Time-Resolved PIV Technique for High Temporal Resolution Measurement of Mechanical Prosthetic Aortic Valve Fluid Dynamics. Int J Artif Organs 2018; 30:153-62. [PMID: 17377910 DOI: 10.1177/039139880703000210] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Prosthetic heart valves (PHVs) have been used to replace diseased native valves for more than five decades. Among these, mechanical PHVs are the most frequently implanted. Unfortunately, these devices still do not achieve ideal behavior and lead to many complications, many of which are related to fluid mechanics. The fluid dynamics of mechanical PHVs are particularly complex and the fine-scale characteristics of such flows call for very accurate experimental techniques. Adequate temporal resolution can be reached by applying time-resolved PIV, a high-resolution dynamic technique which is able to capture detailed chronological changes in the velocity field. The aim of this experimental study is to investigate the evolution of the flow field in a detailed time domain of a commercial bileaflet PHV in a mock-loop mimicking unsteady conditions, by means of time-resolved 2D Particle Image Velocimetry (PIV). The investigated flow field corresponded to the region immediately downstream of the valve plane. Spatial resolution as in “standard” PIV analysis of prosthetic valve fluid dynamics was used. The combination of a Nd:YLF high-repetition-rate double-cavity laser with a high frame rate CMOS camera allowed a detailed, highly temporally resolved acquisition (up to 10000 fps depending on the resolution) of the flow downstream of the PHV. Features that were observed include the non-homogeneity and unsteadiness of the phenomenon and the presence of large-scale vortices within the field, especially in the wake of the valve leaflets. Furthermore, we observed that highly temporally cycle-resolved analysis allowed the different behaviors exhibited by the bileaflet valve at closure to be captured in different acquired cardiac cycles. By accurately capturing hemodynamically relevant time scales of motion, time-resolved PIV characterization can realistically be expected to help designers in improving PHV performance and in furnishing comprehensive validation with experimental data on fluid dynamics numeric modelling.
Collapse
Affiliation(s)
- R Kaminsky
- Institute Biomedical Technology, Ghent University, Ghent, Belgium
| | | | | | | | | | | |
Collapse
|
25
|
M Faghih M, Sharp MK. Characterization of erythrocyte membrane tension for hemolysis prediction in complex flows. Biomech Model Mechanobiol 2018; 17:827-842. [PMID: 29299699 DOI: 10.1007/s10237-017-0995-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 12/16/2017] [Indexed: 10/18/2022]
Abstract
Hemolysis is a persistent issue with blood-contacting devices. Many experimental and theoretical contributions over the last few decades have increased insight into the mechanisms of hemolysis in both laminar and turbulent flows, with the ultimate goal of developing a comprehensive, mechanistic hemolysis model. Many models assume that hemolysis scales with a resultant, scalar stress representing all components of the fluid stress tensor. This study critically evaluates this scalar stress hypothesis by calculating the response of the red blood cell membrane to different types of fluid stress (laminar shear and extension, and three turbulent shear and extension cases), each with the same scalar stress. It was found that even though the scalar stress is the same for all cases, membrane tension varied by up to three orders of magnitude. In addition, extensional flow causes constant tension, while tank-treading in shear flow causes periodic tension, with tank-treading frequency varying by three orders of magnitude among the cases. For turbulent flow, tension also depends on eddy size. It is concluded, therefore, that scalar stress alone is inadequate for scaling hemolysis. Fundamental investigations are needed to establish a new index of the fluid stress tensor that provides reliable hemolysis prediction across the wide range of complex flows that occur in cardiovascular devices.
Collapse
Affiliation(s)
- Mohammad M Faghih
- Biofluid Mechanics Laboratory, Department of Mechanical Engineering, University of Louisville, Louisville, KY, USA
| | - M Keith Sharp
- Biofluid Mechanics Laboratory, Department of Mechanical Engineering, University of Louisville, Louisville, KY, USA.
| |
Collapse
|
26
|
Review of numerical methods for simulation of mechanical heart valves and the potential for blood clotting. Med Biol Eng Comput 2017; 55:1519-1548. [DOI: 10.1007/s11517-017-1688-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/10/2017] [Indexed: 11/26/2022]
|
27
|
Schüle CY, Affeld K, Kossatz M, Paschereit CO, Kertzscher U. Turbulence measurements in an axial rotary blood pump with laser Doppler velocimetry. Int J Artif Organs 2017; 40:0. [PMID: 28430305 DOI: 10.5301/ijao.5000571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND The implantation of rotary blood pumps as ventricular assist devices (VADs) has become a viable therapy for quite a number of patients with end-stage heart failure. However, these rotary blood pumps cause adverse events that are related to blood trauma. It is currently believed that turbulence in the pump flow plays a significant role. But turbulence has not been measured to date because there is no optical access to the flow space in rotary blood pumps because of their opaque casings. METHODS This difficulty is overcome with a scaled-up model of the HeartMate II (HM II) rotary blood pump with a transparent acrylic housing. A 2-component laser Doppler velocimetry (LDV) system was used for the measurement of time resolved velocity profiles and velocity spectra upstream and downstream of the rotor blades. Observing similarity laws, the speed and pump head were adjusted to correspond closely to the design point of the original pump - 10,600 rpm speed and 80 mmHg pressure head. A model fluid consisting of a water-glycerol mixture was used. RESULTS The measured velocity spectra were scalable by the Kolmogorov length and the Kolmogorov length was estimated to be between 14 and 24 µm at original scale, thus being about 1.5 to 3 times the size of a red blood cell. CONCLUSIONS It can be concluded that turbulence is indeed present in the investigated blood pump and that it can be described by Kolmogorov's theory of turbulence. The size of the smallest vortices compares well to the turbulence length scales as found in prosthetic heart valves, for example.
Collapse
Affiliation(s)
- Chan Y Schüle
- Biofluid Mechanics Laboratory, Charité - Universitätsmedizin Berlin, Berlin - Germany
| | - Klaus Affeld
- Biofluid Mechanics Laboratory, Charité - Universitätsmedizin Berlin, Berlin - Germany
| | - Max Kossatz
- Biofluid Mechanics Laboratory, Charité - Universitätsmedizin Berlin, Berlin - Germany
| | - Christian O Paschereit
- Chair of Fluid Dynamics, Hermann-Föttinger-Institut, Technische Universität Berlin, Berlin - Germany
| | - Ulrich Kertzscher
- Biofluid Mechanics Laboratory, Charité - Universitätsmedizin Berlin, Berlin - Germany
| |
Collapse
|
28
|
Sethi P, Murtaza G, Rahman Z, Zaidi S, Helton T, Paul T. Valvular Hemolysis Masquerading as Prosthetic Valve Stenosis. Cureus 2017; 9:e1143. [PMID: 28491484 PMCID: PMC5422110 DOI: 10.7759/cureus.1143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The evaluation of prosthetic valves can provide a unique challenge, and a thoughtful approach is required. High output states like anemia should be kept in the differential when evaluating elevated gradients across prosthetic valves. We present the case of a 69-year-old man with a Starr-Edwards prosthetic aortic valve who presented with symptoms of congestive heart failure and high transvalvular pressure gradients. These symptoms indicate a potential prosthetic valve stenosis. His laboratory evaluation results were consistent with valve-related hemolysis. Resolving his anemia led to a resolution of the symptoms and lowered the pressure gradient on follow-up.
Collapse
Affiliation(s)
| | | | - Zia Rahman
- Internal Medicine, East Tennessee State University
| | - Syed Zaidi
- Internal Medicine, East Tennessee State University
| | - Thomas Helton
- Internal Medicine, James H. Quillen Veteran Affairs Medical Center
| | - Timir Paul
- Cardiology, East Tennessee State University
| |
Collapse
|
29
|
Reynolds Stresses and Hemolysis in Turbulent Flow Examined by Threshold Analysis. FLUIDS 2016. [DOI: 10.3390/fluids1040042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
30
|
Ozturk M, Papavassiliou DV, O'Rear EA. An Approach for Assessing Turbulent Flow Damage to Blood in Medical Devices. J Biomech Eng 2016; 139:2571660. [DOI: 10.1115/1.4034992] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Indexed: 11/08/2022]
Abstract
In this work, contributing factors for red blood cell (RBC) damage in turbulence are investigated by simulating jet flow experiments. Results show that dissipative eddies comparable or smaller in size to the red blood cells cause hemolysis and that hemolysis corresponds to the number and, more importantly, the surface area of eddies that are associated with Kolmogorov length scale (KLS) smaller than about 10 μm. The size distribution of Kolmogorov scale eddies is used to define a turbulent flow extensive property with eddies serving as a means to assess the turbulence effectiveness in damaging cells, and a new hemolysis model is proposed. This empirical model is in agreement with hemolysis results for well-defined systems that exhibit different exposure times and flow conditions, in Couette flow viscometer, capillary tube, and jet flow experiments.
Collapse
Affiliation(s)
- Mesude Ozturk
- Department of Chemical, Biological, and Materials Engineering, Sarkeys Energy Center Room T301, University of Oklahoma, 100 East Boyd Street, Norman, OK 73019 e-mail:
| | - Dimitrios V. Papavassiliou
- Department of Chemical, Biological, and Materials Engineering, Sarkeys Energy Center Room T301, University of Oklahoma, 100 East Boyd Street, Norman, OK 73019 e-mail:
| | - Edgar A. O'Rear
- Department of Chemical, Biological, and Materials Engineering, Sarkeys Energy Center Room T301, University of Oklahoma Biomedical Engineering Center, 100 East Boyd Street, Norman, OK 73019 e-mail:
| |
Collapse
|
31
|
Xie D, Leng Y, Jing F, Huang N. A brief review of bio-tribology in cardiovascular devices. BIOSURFACE AND BIOTRIBOLOGY 2015. [DOI: 10.1016/j.bsbt.2015.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
|
32
|
Ozturk M, O'Rear EA, Papavassiliou DV. Hemolysis Related to Turbulent Eddy Size Distributions Using Comparisons of Experiments to Computations. Artif Organs 2015; 39:E227-39. [DOI: 10.1111/aor.12572] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mesude Ozturk
- Department of Chemical, Biological and Materials Engineering; University of Oklahoma; Norman OK USA
| | - Edgar A. O'Rear
- Department of Chemical, Biological and Materials Engineering; University of Oklahoma; Norman OK USA
- Bioengineering Center; University of Oklahoma; Norman OK USA
| | | |
Collapse
|
33
|
Erratum to: Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions. Cardiovasc Eng Technol 2015; 6:577-89. [DOI: 10.1007/s13239-015-0243-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
34
|
Stauffer MA, Reibson JD, Yeager EE, Jhun CS, Newswanger RK, Cysyk JP, Weiss WJ, Rosenberg G. Effect of Turbulent Flow on Hemolysis Utilizing a Turbulent Free Jet1. J Med Device 2015. [DOI: 10.1115/1.4030117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Megan A. Stauffer
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| | - John D. Reibson
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| | - Eric E. Yeager
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| | - Choon-Sik Jhun
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| | | | - Joshua P. Cysyk
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| | - William J. Weiss
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| | - Gerson Rosenberg
- Department of Surgery, Penn State College of Medicine, Hershey, PA 17033
| |
Collapse
|
35
|
Andersson M, Lantz J, Ebbers T, Karlsson M. Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions. Cardiovasc Eng Technol 2015; 6:281-93. [PMID: 26577361 DOI: 10.1007/s13239-015-0218-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 02/13/2015] [Indexed: 01/01/2023]
Abstract
Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies.
Collapse
Affiliation(s)
- Magnus Andersson
- Department of Management and Engineering (IEI), Linköping University, 581 83, Linköping, Sweden. .,Swedish e-Science Research Center (SeRC), Stockholm, Sweden.
| | - Jonas Lantz
- Department of Science and Technology, Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| | - Tino Ebbers
- Department of Science and Technology, Linköping University, Linköping, Sweden.,Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| | - Matts Karlsson
- Department of Management and Engineering (IEI), Linköping University, 581 83, Linköping, Sweden.,Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.,Swedish e-Science Research Center (SeRC), Stockholm, Sweden
| |
Collapse
|
36
|
Maddah S, Navidbakhsh M. A Cell Damages Study in Pulsatile Blood Flow through Two- and Three-Dimensional Obstructed Vessels Using the Cosserat Continuum Approach. J DISPER SCI TECHNOL 2014. [DOI: 10.1080/01932691.2014.907541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
37
|
The effect of turbulent viscous shear stress on red blood cell hemolysis. J Artif Organs 2014; 17:178-85. [PMID: 24619800 DOI: 10.1007/s10047-014-0755-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 01/14/2014] [Indexed: 10/25/2022]
Abstract
Non-physiologic turbulent flow occurs in medical cardiovascular devices resulting in hemodynamic stresses that may damage red blood cells (RBC) and cause hemolysis. Hemolysis was previously thought to result from Reynolds shear stress (RSS) in turbulent flows. A more recent hypothesis suggests that turbulent viscous shear stresses (TVSS) at spatial scales similar in size to RBCs are related to their damage. We applied two-dimensional digital particle image velocimetry to measure the flow field of a free-submerged axisymmetric jet that was utilized to hemolyze porcine RBCs in selected locations. Assuming a dynamic equilibrium for the sub-grid scale (SGS) energy flux between the resolved and the sub-grid scales, the SGS energy flux was calculated from the strain rate tensor computed from the resolved velocity fields. The SGS stress was determined by the Smagorinsky model, from which the turbulence dissipation rate and then TVSS were estimated. Our results showed the hemolytic threshold of the Reynolds stresses was up to 517 Pa, and the TVSSs were at least an order of magnitude less than the RSS. The results provide further insight into the relationship between turbulence and RBC damage.
Collapse
|
38
|
Bluestein D. Research approaches for studying flow-induced thromboembolic complications in blood recirculating devices. Expert Rev Med Devices 2014; 1:65-80. [PMID: 16293011 DOI: 10.1586/17434440.1.1.65] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The advent of implantable blood recirculating devices has provided life-saving solutions to patients with severe cardiovascular diseases. Recently it has been reported that ventricular assist devices are superior to drug therapy. The implantable total artificial heart is showing promise as a potential solution to the chronic shortage of available heart transplants. Prosthetic heart valves are routinely used for replacing diseased heart valves. However, all of these devices share a common problem--significant complications such as hemolysis and thromboembolism often arise after their implantation. Elevated flow stresses that are present in the nonphysiologic geometries of blood recirculating devices, enhance their propensity to initiate thromboembolism by chronically activating the blood platelets. This, rather than hemolysis, appears to be the salient aspect of blood trauma in devices. Limitations in characterizing and controlling relevant aspects of the flow-induced mechanical stimuli and the platelet response, hampers our ability to achieve design optimization for these devices. The main objective of this article is to describe state-of-the-art numerical, experimental, and in vivo tools, that facilitate elucidation of flow-induced mechanisms leading to thromboembolism in prosthetic devices. Such techniques are giving rise to an accountable model for flow-induced thrombogenicity, and to a methodology that has the potential to transform current device design and testing practices. It might lead to substantial time and cost savings during the research and development phase, and has the potential to reduce the risks that patients implanted with these devices face, lower the ensuing healthcare costs, and offer viable long-term solutions for these patients.
Collapse
Affiliation(s)
- Danny Bluestein
- Department of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, NY 11794-8181, USA.
| |
Collapse
|
39
|
Hope TA, Kvitting JPE, Hope MD, Miller DC, Markl M, Herfkens RJ. Evaluation of Marfan patients status post valve-sparing aortic root replacement with 4D flow. Magn Reson Imaging 2013; 31:1479-84. [PMID: 23706513 DOI: 10.1016/j.mri.2013.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 03/05/2013] [Accepted: 04/06/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Over the past two decades elective valve-sparing aortic root replacement (V-SARR) has become more common in the treatment of patients with aortic root and ascending aortic aneurysms. Currently there are little data available to predict complications in the post-operative population. The study goal was to determine if altered flow patterns in the thoracic aorta, as measured by MRI, are associated with complications after V-SARR. METHODS Time-resolved three-dimensional phase-contrast MRI (4D flow) was used to image 12 patients with Marfan syndrome after V-SARR. The patients were followed up for an average of 5.8 years after imaging and 8.2 years after surgery. Additionally 5 volunteers were imaged for comparison. Flow profiles were visualized during peak systole using streamlines. Wall shear stress estimates and normalized flow displacement were evaluated at multiple planes in the thoracic aorta. RESULTS During the follow-up period, a single patient developed a Stanford Type B aortic dissection. At initial imaging, prior to the development of the dissection, the patient had altered flow patterns, wall shear stress estimates, and increased normalized flow displacement in the thoracic aorta in comparison to the remaining V-SARR patients and volunteers. CONCLUSIONS This is the first follow-up study of patients after 4D flow imaging. An aortic dissection developed in one patient with altered flow patterns and hemodynamic stresses in the thoracic aorta. These results suggest that flow and altered hemodynamics may play a role in the development of post-operative intramural hematomas and dissections.
Collapse
Affiliation(s)
- Thomas A Hope
- Department of Radiology, Stanford University, Stanford, CA, USA.
| | | | | | | | | | | |
Collapse
|
40
|
Evaluation of shear stress accumulation on blood components in normal and dysfunctional bileaflet mechanical heart valves using smoothed particle hydrodynamics. J Biomech 2012; 45:2637-44. [PMID: 22980575 DOI: 10.1016/j.jbiomech.2012.08.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 07/04/2012] [Accepted: 08/09/2012] [Indexed: 11/24/2022]
Abstract
Evaluating shear induced hemodynamic complications is one of the major concerns in design of the mechanical heart valves (MHVs). The monitoring of these events relies on both numerical simulations and experimental measurements. Currently, numerical approaches are mainly based on a combined Eulerian-Lagrangian approach. A more straightforward evaluation can be based on the Lagrangian analysis of the whole blood. As a consequence, Lagrangian meshfree methods are more adapted to such evaluation. In this study, smoothed particle hydrodynamics (SPH), a fully meshfree particle method originated to simulate compressible astrophysical flows, is applied to study the flow through a normal and a dysfunctional bileaflet mechanical heart valves (BMHVs). The SPH results are compared with the reference data. The accumulation of shear stress patterns on blood components illustrates the important role played by non-physiological flow patterns and mainly vortical structures in this issue. The statistical distribution of particles with respect to shear stress loading history provides important information regarding the relative number of blood components that can be damaged. This can be used as a measure of the response of blood components to the presence of the valve implant or any implantable medical device. This work presents the first attempt to simulate pulsatile flow through BMHVs using SPH method.
Collapse
|
41
|
Li CP, Lu PC. Numerical comparison of the closing dynamics of a new trileaflet and a bileaflet mechanical aortic heart valve. J Artif Organs 2012; 15:364-74. [DOI: 10.1007/s10047-012-0650-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 05/08/2012] [Indexed: 11/24/2022]
|
42
|
|
43
|
Bellofiore A, Quinlan NJ. High-Resolution Measurement of the Unsteady Velocity Field to Evaluate Blood Damage Induced by a Mechanical Heart Valve. Ann Biomed Eng 2011; 39:2417-29. [DOI: 10.1007/s10439-011-0329-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 05/14/2011] [Indexed: 11/24/2022]
|
44
|
|
45
|
Borazjani I, Sotiropoulos F. The effect of implantation orientation of a bileaflet mechanical heart valve on kinematics and hemodynamics in an anatomic aorta. J Biomech Eng 2011; 132:111005. [PMID: 21034146 DOI: 10.1115/1.4002491] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We carry out three-dimensional high-resolution numerical simulations of a bileaflet mechanical heart valve under physiologic pulsatile flow conditions implanted at different orientations in an anatomic aorta obtained from magnetic resonance imaging (MRI) of a volunteer. We use the extensively validated for heart valve flow curvilinear-immersed boundary (CURVIB) fluid-structure interaction (FSI) solver in which the empty aorta is discretized with a curvilinear, aorta-conforming grid while the valve is handled as an immersed boundary. The motion of the valve leaflets are calculated through a strongly coupled FSI algorithm implemented in conjunction with the Aitken convergence acceleration technique. We perform simulations for three valve orientations, which differ from each other by 45 deg and compare the results in terms of leaflet motion and flow field. We show that the valve implanted symmetrically relative to the symmetry plane of the ascending aorta curvature exhibits the smallest overall asymmetry in the motion of its two leaflets and lowest rebound during closure. Consequently, we hypothesize that this orientation is beneficial to reduce the chance of intermittent regurgitation. Furthermore, we find that the valve orientation does not significantly affect the shear stress distribution in the aortic lumen, which is in agreement with previous studies.
Collapse
Affiliation(s)
- Iman Borazjani
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414, USA.
| | | |
Collapse
|
46
|
Hutchison C, Sullivan P, Ethier CR. Measurements of steady flow through a bileaflet mechanical heart valve using stereoscopic PIV. Med Biol Eng Comput 2010; 49:325-35. [DOI: 10.1007/s11517-010-0705-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 10/21/2010] [Indexed: 11/29/2022]
|
47
|
Xenos M, Girdhar G, Alemu Y, Jesty J, Slepian M, Einav S, Bluestein D. Device Thrombogenicity Emulator (DTE)--design optimization methodology for cardiovascular devices: a study in two bileaflet MHV designs. J Biomech 2010; 43:2400-9. [PMID: 20483411 DOI: 10.1016/j.jbiomech.2010.04.020] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 04/15/2010] [Accepted: 04/16/2010] [Indexed: 12/29/2022]
Abstract
Patients who receive prosthetic heart valve (PHV) implants require mandatory anticoagulation medication after implantation due to the thrombogenic potential of the valve. Optimization of PHV designs may facilitate reduction of flow-induced thrombogenicity and reduce or eliminate the need for post-implant anticoagulants. We present a methodology entitled Device Thrombogenicty Emulator (DTE) for optimizing the thrombo-resistance performance of PHV by combining numerical and experimental approaches. Two bileaflet mechanical heart valves (MHV) designs, St. Jude Medical (SJM) and ATS, were investigated by studying the effect of distinct flow phases on platelet activation. Transient turbulent and direct numerical simulations (DNS) were conducted, and stress loading histories experienced by the platelets were calculated along flow trajectories. The numerical simulations indicated distinct design dependent differences between the two valves. The stress loading waveforms extracted from the numerical simulations were programmed into a hemodynamic shearing device (HSD), emulating the flow conditions past the valves in distinct 'hot-spot' flow regions that are implicated in MHV thrombogenicity. The resultant platelet activity was measured with a modified prothrombinase assay, and was found to be significantly higher in the SJM valve, mostly during the regurgitation phase. The experimental results were in excellent agreement with the calculated platelet activation potential. This establishes the utility of the DTE methodology for serving as a test bed for evaluating design modifications for achieving better thrombogenic performance for such devices.
Collapse
Affiliation(s)
- Michalis Xenos
- Department of Biomedical Engineering, Stony Brook University, HSC T18-030, Stony Brook, NY 11794-8181, USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
Computational simulations are playing an increasingly important role in enhancing our understanding of the normal human physiological function, etiology of diseased states, surgical and interventional planning, and in the design and evaluation of artificial implants. Researchers are taking advantage of computational simulations to speed up the initial design of implantable devices before a prototype is developed and hence able to reduce animal experimentation for the functional evaluation of the devices under development. A review of the reported studies to date relevant to the simulation of the native and prosthetic heart valve dynamics is the subject of the present paper. Potential future directions toward multi-scale simulation studies for our further understanding of the physiology and pathophysiology of heart valve dynamics and valvular implants are also discussed.
Collapse
|
49
|
Borazjani I, Ge L, Sotiropoulos F. High-resolution fluid-structure interaction simulations of flow through a bi-leaflet mechanical heart valve in an anatomic aorta. Ann Biomed Eng 2010; 38:326-44. [PMID: 19806458 PMCID: PMC3154744 DOI: 10.1007/s10439-009-9807-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Accepted: 09/21/2009] [Indexed: 10/20/2022]
Abstract
We have performed high-resolution fluid-structure interaction simulations of physiologic pulsatile flow through a bi-leaflet mechanical heart valve (BMHV) in an anatomically realistic aorta. The results are compared with numerical simulations of the flow through an identical BMHV implanted in a straight aorta. The comparisons show that although some of the salient features of the flow remain the same, the aorta geometry can have a major effect on both the flow patterns and the motion of the valve leaflets. For the studied configuration, for instance, the BMHV leaflets in the anatomic aorta open much faster and undergo a greater rebound during closing than the same valve in the straight axisymmetric aorta. Even though the characteristic triple-jet structure does emerge downstream of the leaflets for both cases, for the anatomic case the leaflet jets spread laterally and diffuse much faster than in the straight aorta due to the aortic curvature and complex shape of the anatomic sinus. Consequently the leaflet shear layers in the anatomic case remain laminar and organized for a larger portion of the accelerating phase as compared to the shear layers in the straight aorta, which begin to undergo laminar instabilities well before peak systole is reached. For both cases, however, the flow undergoes a very similar explosive transition to the small-scale, turbulent-like state just prior to reaching peak systole. The local maximum shear stress is used as a metric to characterize the mechanical environment experienced by blood cells. Pockets of high local maximum shear are found to be significantly more widespread in the anatomic aorta than in the straight aorta throughout the cardiac cycle. Pockets of high local maximum shear were located near the leaflets and in the aortic arc region. This work clearly demonstrates the importance of the aortic geometry on the flow phenomena in a BMHV and demonstrates the potential of our computational method to carry out image-based patient-specific simulations for clinically relevant studies of heart valve hemodynamics.
Collapse
Affiliation(s)
- Iman Borazjani
- St. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Liang Ge
- Department of Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Fotis Sotiropoulos
- St. Anthony Falls Laboratory, Department of Civil Engineering, University of Minnesota, Minneapolis, MN, USA
| |
Collapse
|
50
|
Li CP, Lo CW, Lu PC. Estimation of Viscous Dissipative Stresses Induced by a Mechanical Heart Valve Using PIV Data. Ann Biomed Eng 2009; 38:903-16. [DOI: 10.1007/s10439-009-9867-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 12/02/2009] [Indexed: 10/20/2022]
|