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Seifelnasr A, Si X, Xi J. Effects of Nozzle Retraction Elimination on Spray Distribution in Middle-Posterior Turbinate Regions: A Comparative Study. Pharmaceutics 2024; 16:683. [PMID: 38794345 PMCID: PMC11124954 DOI: 10.3390/pharmaceutics16050683] [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: 03/31/2024] [Revised: 05/08/2024] [Accepted: 05/17/2024] [Indexed: 05/26/2024] Open
Abstract
The standard multi-dose nasal spray pump features an integrated actuator and nozzle, which inevitably causes a retraction of the nozzle tip during application. The retraction stroke is around 5.5 mm and drastically reduces the nozzle's insertion depth, which further affects the initial nasal spray deposition and subsequent translocation, potentially increasing drug wastes and dosimetry variability. To address this issue, we designed a new spray pump that separated the nozzle from the actuator and connected them with a flexible tube, thereby eliminating nozzle retraction during application. The objective of this study is to test the new device's performance in comparison to the conventional nasal pump in terms of spray generation, plume development, and dosimetry distribution. For both devices, the spray droplet size distribution was measured using a laser diffraction particle analyzer. Plume development was recorded with a high-definition camera. Nasal dosimetry was characterized in two transparent nasal cavity casts (normal and decongested) under two breathing conditions (breath-holding and constant inhalation). The nasal formulation was a 0.25% w/v methyl cellulose aqueous solution with a fluorescent dye. For each test case, the temporospatial spray translocation in the nasal cavity was recorded, and the final delivered doses were quantified in five nasal regions. The results indicate minor differences in droplet size distribution between the two devices. The nasal plume from the new device presents a narrower plume angle. The head orientation, the depth at which the nozzle is inserted into the nostril, and the administration angle play crucial roles in determining the initial deposition of nasal sprays as well as the subsequent translocation of the liquid film/droplets. Quantitative measurements of deposition distributions in the nasal models were augmented with visualization recordings to evaluate the delivery enhancements introduced by the new device. With an extension tube, the modified device produced a lower spray output and delivered lower doses in the front, middle, and back turbinate than the conventional nasal pump. However, sprays from the new device were observed to penetrate deeper into the nasal passages, predominantly through the middle-upper meatus. This resulted in consistently enhanced dosing in the middle-upper turbinate regions while at the cost of higher drug loss to the pharynx.
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Affiliation(s)
- Amr Seifelnasr
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA 01854, USA;
| | - Xiuhua Si
- Department of Aerospace, Industrial and Mechanical Engineering, California Baptist University, Riverside, CA 92504, USA;
| | - Jinxiang Xi
- Department of Biomedical Engineering, University of Massachusetts, Lowell, MA 01854, USA;
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Watson CT, Ward SC, Rizzo SA, Redaelli A, Manning KB. Influence of Hematocrit Level and Integrin α IIbβ III Function on vWF-Mediated Platelet Adhesion and Shear-Induced Platelet Aggregation in a Sudden Expansion. Cell Mol Bioeng 2024; 17:49-65. [PMID: 38435796 PMCID: PMC10902252 DOI: 10.1007/s12195-024-00796-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/30/2024] [Indexed: 03/05/2024] Open
Abstract
Purpose Shear-mediated thrombosis is a clinically relevant phenomenon that underlies excessive arterial thrombosis and device-induced thrombosis. Red blood cells are known to mechanically contribute to physiological hemostasis through margination of platelets and vWF, facilitating the unfurling of vWF multimers, and increasing the fraction of thrombus-contacting platelets. Shear also plays a role in this phenomenon, increasing both the degree of margination and the near-wall forces experienced by vWF and platelets leading to unfurling and activation. Despite this, the contribution of red blood cells in shear-induced platelet aggregation has not been fully investigated-specifically the effect of elevated hematocrit has not yet been demonstrated. Methods Here, a microfluidic model of a sudden expansion is presented as a platform for investigating platelet adhesion at hematocrits ranging from 0 to 60% and shear rates ranging from 1000 to 10,000 s-1. The sudden expansion geometry models nonphysiological flow separation characteristic to mechanical circulatory support devices, and the validatory framework of the FDA benchmark nozzle. PDMS microchannels were fabricated and coated with human collagen. Platelets were fluorescently tagged, and blood was reconstituted at variable hematocrit prior to perfusion experiments. Integrin function of selected blood samples was inhibited by a blocking antibody, and platelet adhesion and aggregation over the course of perfusion was monitored. Results Increasing shear rates at physiological and elevated hematocrit levels facilitate robust platelet adhesion and formation of large aggregates. Shear-induced platelet aggregation is demonstrated to be dependent on both αIIbβIII function and the presence of red blood cells. Inhibition of αIIbβIII results in an 86.4% reduction in overall platelet adhesion and an 85.7% reduction in thrombus size at 20-60% hematocrit. Hematocrit levels of 20% are inadequate for effective platelet margination and subsequent vWF tethering, resulting in notable decreases in platelet adhesion at 5000 and 10,000 s-1 compared to 40% and 60%. Inhibition of αIIbβIII triggered dramatic reductions in overall thrombus coverage and large aggregate formation. Stability of platelets tethered by vWF are demonstrated to be αIIbβIII-dependent, as adhesion of single platelets treated with A2A9, an anti-αIIbβIII blocking antibody, is transient and did not lead to sustained thrombus formation. Conclusions This study highlights driving factors in vWF-mediated platelet adhesion that are relevant to clinical suppression of shear-induced thrombosis and in vitro assays of platelet adhesion. Primarily, increasing hematocrit promotes platelet margination, permitting shear-induced platelet aggregation through αIIbβIII-mediated adhesion at supraphysiological shear rates. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-024-00796-0.
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Affiliation(s)
- Connor T. Watson
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA USA
| | - Shane C. Ward
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA USA
| | - Stefano A. Rizzo
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Keefe B. Manning
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA USA
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA USA
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Rasooli R, Giljarhus KET, Hiorth A, Jolma IW, Vinningland JL, de Lange C, Brun H, Holmstrom H. In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients. Cardiovasc Eng Technol 2023; 14:428-446. [PMID: 36877450 PMCID: PMC10412470 DOI: 10.1007/s13239-023-00663-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 02/06/2023] [Indexed: 03/07/2023]
Abstract
PURPOSE The Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients. METHODS A self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance. RESULTS The assist device provided a significant IVC pressure drop of more than 3.2 mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1 mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature. CONCLUSIONS A self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.
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Affiliation(s)
- Reza Rasooli
- Department of Energy Resources, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway.
| | - Knut Erik Teigen Giljarhus
- Department of Mechanical and Structural Engineering and Materials Science, University of Stavanger, 4036, Stavanger, Norway
| | - Aksel Hiorth
- Department of Energy Resources, Faculty of Science and Technology, University of Stavanger, 4036, Stavanger, Norway
| | - Ingunn Westvik Jolma
- Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, 4036, Stavanger, Norway
| | | | - Charlotte de Lange
- Department of Paediatric Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Henrik Brun
- Section for Medical Cybernetics and Image Processing, The Intervention Centre, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Paediatric Cardiology, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Henrik Holmstrom
- Department of Paediatric Cardiology, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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4
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Xiang WJ, Huo JD, Wu WT, Wu P. Influence of Inlet Boundary Conditions on the Prediction of Flow Field and Hemolysis in Blood Pumps Using Large-Eddy Simulation. Bioengineering (Basel) 2023; 10:bioengineering10020274. [PMID: 36829767 PMCID: PMC9952191 DOI: 10.3390/bioengineering10020274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/11/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Inlet boundary conditions (BC) are one of the uncertainties which may influence the prediction of flow field and hemolysis in blood pumps. This study investigated the influence of inlet BC, including the length of inlet pipe, type of inlet BC (mass flow rate or experimental velocity profile) and turbulent intensity (no perturbation, 5%, 10%, 20%) on the prediction of flow field and hemolysis of a benchmark centrifugal blood pump (the FDA blood pump) and a commercial axial blood pump (Heartmate II), using large-eddy simulation. The results show that the influence of boundary conditions on integral pump performance metrics, including pressure head and hemolysis, is negligible. The influence on local flow structures, such as velocity distributions, mainly existed in the inlet. For the centrifugal FDA blood pump, the influence of type of inlet BC and inlet position on velocity distributions can also be observed at the diffuser. Overall, the effects of position of inlet and type of inlet BC need to be considered if local flow structures are the focus, while the influence of turbulent intensity is negligible and need not be accounted for during numerical simulations of blood pumps.
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Affiliation(s)
- Wen-Jing Xiang
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou 215000, China
| | - Jia-Dong Huo
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou 215000, China
| | - Wei-Tao Wu
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210095, China
- Correspondence: (W.-T.W.); (P.W.)
| | - Peng Wu
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou 215000, China
- Correspondence: (W.-T.W.); (P.W.)
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Ponnaluri SV, Hariharan P, Herbertson LH, Manning KB, Malinauskas RA, Craven BA. Results of the Interlaboratory Computational Fluid Dynamics Study of the FDA Benchmark Blood Pump. Ann Biomed Eng 2023; 51:253-269. [PMID: 36401112 DOI: 10.1007/s10439-022-03105-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 10/21/2022] [Indexed: 11/19/2022]
Abstract
Computational fluid dynamics (CFD) is widely used to simulate blood-contacting medical devices. To be relied upon to inform high-risk decision making, however, model credibility should be demonstrated through validation. To provide robust data sets for validation, researchers at the FDA and collaborators developed two benchmark medical device flow models: a nozzle and a centrifugal blood pump. Experimental measurements of the flow fields and hemolysis were acquired using each model. Concurrently, separate open interlaboratory CFD studies were performed in which participants from around the world, who were blinded to the measurements, submitted CFD predictions of each benchmark model. In this study, we report the results of the interlaboratory CFD study of the FDA benchmark blood pump. We analyze the results of 24 CFD submissions using a wide range of different flow solvers, methods, and modeling parameters. To assess the accuracy of the CFD predictions, we compare the results with experimental measurements of three quantities of interest (pressure head, velocity field, and hemolysis) at different pump operating conditions. We also investigate the influence of different CFD methods and modeling choices used by the participants. Our analyses reveal that, while a number of CFD submissions accurately predicted the pump performance for individual cases, no single participant was able to accurately predict all quantities of interest across all conditions. Several participants accurately predicted the pressure head at all conditions and the velocity field in all but one or two cases. Only one of the eight participants who submitted hemolysis results accurately predicted absolute plasma free hemoglobin levels at a majority of the conditions, though most participants were successful at predicting relative hemolysis levels between conditions. Overall, this study highlights the need to validate CFD modeling of rotary blood pumps across the entire range of operating conditions and for all quantities of interest, as some operating conditions and regions (e.g., the pump diffuser) are more challenging to accurately predict than others. All quantities of interest should be validated because, as shown here, it is possible to accurately predict hemolysis despite having relatively inaccurate predictions of the flow field.
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Affiliation(s)
- Sailahari V Ponnaluri
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA.,Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Prasanna Hariharan
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Luke H Herbertson
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.,Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Richard A Malinauskas
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Brent A Craven
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA.
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Torner B, Frank D, Grundmann S, Wurm FH. Flow simulation-based particle swarm optimization for developing improved hemolysis models. Biomech Model Mechanobiol 2022; 22:401-416. [PMID: 36441414 PMCID: PMC10097800 DOI: 10.1007/s10237-022-01653-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 10/23/2022] [Indexed: 11/29/2022]
Abstract
AbstractThe improvement and development of blood-contacting devices, such as mechanical circulatory support systems, is a life saving endeavor. These devices must be designed in such a way that they ensure the highest hemocompatibility. Therefore, in-silico trials (flow simulations) offer a quick and cost-effective way to analyze and optimize the hemocompatibility and performance of medical devices. In that regard, the prediction of blood trauma, such as hemolysis, is the key element to ensure the hemocompatibility of a device. But, despite decades of research related to numerical hemolysis models, their accuracy and reliability leaves much to be desired. This study proposes a novel optimization path, which is capable of improving existing models and aid in the development of future hemolysis models. First, flow simulations of three, turbulent blood flow test cases (capillary tube, FDA nozzle, FDA pump) were performed and hemolysis was numerically predicted by the widely-applied stress-based hemolysis models. Afterward, a multiple-objective particles swarm optimization (MOPSO) was performed to tie the physiological stresses of the simulated flow field to the measured hemolysis using an equivalent of over one million numerically determined hemolysis predictions. The results show that our optimization is capable of improving upon existing hemolysis models. However, it also unveils some deficiencies and limits of hemolysis prediction with stress-based models, which will need to be addressed in order to improve its reliability.
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Examining the universality of the hemolysis power law model from simulations of the FDA nozzle using calibrated model coefficients. Biomech Model Mechanobiol 2022; 22:433-451. [PMID: 36418603 PMCID: PMC10101913 DOI: 10.1007/s10237-022-01655-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 10/27/2022] [Indexed: 11/25/2022]
Abstract
Computational fluid dynamics (CFD) is widely used to predict mechanical hemolysis in medical devices. The most popular hemolysis model is the stress-based power law model that is based on an empirical correlation between hemoglobin release from red blood cells (RBCs) and the magnitude of flow-induced stress and exposure time. Empirical coefficients are traditionally calibrated using data from experiments in simplified Couette-type blood-shearing devices with uniform-shear laminar flow and well-defined exposure times. Use of such idealized coefficients in simulations of real medical devices with complex hemodynamics is thought to be a primary reason for the historical inaccuracy of absolute hemolysis predictions using the power law model. Craven et al. (Biomech Model Mechanobiol 18:1005-1030, 2019) recently developed a CFD-based Kriging surrogate modeling approach for calibrating empirical coefficients in real devices that could potentially be used to more accurately predict absolute hemolysis. In this study, we use the FDA benchmark nozzle to investigate whether utilizing such calibrated coefficients improves the predictive accuracy of the standard Eulerian power law model. We first demonstrate the credibility of our CFD flow simulations by comparing with particle image velocimetry measurements. We then perform hemolysis simulations and compare the results with in vitro experiments. Importantly, the simulations use coefficients calibrated for the flow of a suspension of bovine RBCs through a small capillary tube, which is relatively comparable to the flow of bovine blood through the FDA nozzle. The results show that the CFD predictions of relative hemolysis in the FDA nozzle are reasonably accurate. The absolute predictions are, however, highly inaccurate with modified index of hemolysis values from CFD in error by roughly three orders of magnitude compared with the experiments, despite using calibrated model coefficients from a relatively similar geometry. We rigorously examine the reasons for the inaccuracy that include differences in the flow conditions in the hemolytic regions of each device and the lack of universality of the hemolysis power law model that is entirely empirical. Thus, while the capability to predict relative hemolysis is valuable for product development, further improvements are needed before the power law model can be relied upon to accurately predict the absolute hemolytic potential of a medical device.
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Huang F, Noël R, Berg P, Hosseini SA. Simulation of the FDA nozzle benchmark: A lattice Boltzmann study. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106863. [PMID: 35617810 DOI: 10.1016/j.cmpb.2022.106863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/20/2022] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Contrary to flows in small intracranial vessels, many blood flow configurations such as those found in aortic vessels and aneurysms involve larger Reynolds numbers and, therefore, transitional or turbulent conditions. Dealing with such systems require both robust and efficient numerical methods. METHODS We assess here the performance of a lattice Boltzmann solver with full Hermite expansion of the equilibrium and central Hermite moments collision operator at higher Reynolds numbers, especially for under-resolved simulations. To that end the food and drug administration's benchmark nozzle is considered at three different Reynolds numbers covering all regimes: (1) laminar at a Reynolds number of 500, (2) transitional at a Reynolds number of 3500, and (3) low-level turbulence at a Reynolds number of 6500. RESULTS The lattice Boltzmann results are compared with previously published inter-laboratory experimental data obtained by particle image velocimetry. Our results show good agreement with the experimental measurements throughout the nozzle, demonstrating the good performance of the solver even in under-resolved simulations. CONCLUSION In this manner, fast but sufficiently accurate numerical predictions can be achieved for flow configurations of practical interest regarding medical applications.
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Affiliation(s)
- Feng Huang
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke", Magdeburg D-39106, Germany
| | - Romain Noël
- Univ. Gustave Eiffel, Inria, Cosys/SII, I4S, Bouguenais F-44344, France
| | - Philipp Berg
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke", Magdeburg D-39106, Germany; Research Campus STIMULATE, University of Magdeburg "Otto von Guericke", Magdeburg, D-39106, Germany
| | - Seyed Ali Hosseini
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke", Magdeburg D-39106, Germany; Department of Mechanical and Process Engineering, ETH Zürich, Zürich 8092, Switzerland.
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Qiao Y, Luo K, Fan J. Computational Prediction of Thrombosis in Food and Drug Administration's Benchmark Nozzle. Front Physiol 2022; 13:867613. [PMID: 35547578 PMCID: PMC9081348 DOI: 10.3389/fphys.2022.867613] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
Thrombosis seriously threatens human cardiovascular health and the safe operation of medical devices. The Food and Drug Administration’s (FDA) benchmark nozzle model was designed to include the typical structure of medical devices. However, the thrombosis in the FDA nozzle has yet not been investigated. The objective of this study is to predict the thrombus formation process in the idealized medical device by coupling computational fluid dynamics and a macroscopic hemodynamic-based thrombus model. We developed the hemodynamic-based thrombus model by considering the effect of platelet consumption. The thrombus model was quantitatively validated by referring to the latest thrombosis experiment, which was performed in a backward-facing step with human blood flow. The same setup was applied in the FDA nozzle to simulate the thrombus formation process. The thrombus shaped like a ring was firstly observed in the FDA benchmark nozzle. Subsequently, the accuracy of the shear-stress transport turbulence model was confirmed in different turbulent flow conditions. Five scenarios with different Reynolds numbers were carried out. We found that turbulence could change the shape of centrosymmetric thrombus to axisymmetric and high Reynolds number blood flow would delay or even prevent thrombosis. Overall, the present study reports the thrombosis process in the FDA benchmark nozzle using the numerical simulation method, and the primary findings may shed light on the effect of turbulence on thrombosis.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.,Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.,Shanghai Institute for Advanced Study of Zhejiang University, Shanghai, China
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Wu P, Huo JD, Zhang ZJ, Wang CJ. The influence of non-conformal grid interfaces on the results of large eddy simulation of centrifugal blood pumps. Artif Organs 2022; 46:1804-1816. [PMID: 35436356 DOI: 10.1111/aor.14263] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 02/26/2022] [Accepted: 04/08/2022] [Indexed: 11/27/2022]
Abstract
BACKGROUND Computational fluid dynamics has been widely used to assist the design and evaluation of blood pumps. Discretization errors associated with computational grid may influence the credibility of numerical simulations. Non-conformal grid interfaces commonly exist in rotary machines, including rotary blood pumps. Should grid size across the interface differ greatly, large errors may occur. METHODS This study explored the effects of non-conformal grid interface on the prediction of the flow field and hemolysis in blood pumps using large eddy simulation (LES). Two benchmarks, a nozzle model and a centrifugal blood pump were chosen as test cases. RESULTS This study found that non-conformal grid interfaces with considerable change of grid sizes led to discontinuities of flow variables and brought errors to metrics such as pressure head (7%) and hemolysis (up to 14%). CONCLUSIONS The results on the full unstructured grid are more accurate with negligible changes of flow variables across the non-conformal grid interface. A full unstructured grid should be employed for centrifugal blood pumps to minimize the influence of non-conformal grid interfaces for LES simulations.
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Affiliation(s)
- Peng Wu
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Jia-Dong Huo
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Zi-Jian Zhang
- Artificial Organ Technology Laboratory, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Chun-Ju Wang
- Robotics and Microsystems Center, School of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
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Jiang T, Huang Z, Li J, Zhou Y, Xiong C. Effect of Nozzle Geometry on the Flow Dynamics and Resistance Inside and Outside the Cone-Straight Nozzle. ACS OMEGA 2022; 7:9652-9665. [PMID: 35356694 PMCID: PMC8943807 DOI: 10.1021/acsomega.1c07050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
The cone-straight nozzle has been commonly utilized in various applications, such as cleaning, cutting, and drilling, and hence investigated extensively with simulations and experiments. However, the internal flow patterns and dynamics, as well as the influence of internal flow on jetting performance, remain unclear. In this study, we carry out both experiments and computational fluid dynamics to understand the effect of different converging angles of the cone-straight nozzle on internal and external flow patterns. Nozzle flows are simulated by a large eddy simulations model and further compared with the experimental flow fields obtained by a particle image velocimetry (PIV) method. Nozzles with different converging angles and throat lengths have been used experimentally. The influence of nozzle converging angle, throat length, and inlet flow speed on flow field, skin friction resistance, and viscous force is discussed. Associated boundary layer transition and separation are investigated comparatively. The flow discharge coefficient and flow core length are measured by the PIV test system with a high-pressure pump. The experimental results show that a specific converging angle and flow speed can cause the boundary layer transition and separation. Skin friction resistance increases first and then decreases with the increase of inlet flow speed when the angle is larger than 20°. The resistance decreases gradually when the angle is lower than 15°. Importantly, the skin friction resistance remains a lower level when the converging angle is 15°, in agreement with the previous research results. The experimental results show that the nozzle with a converging angle of 10° or 15° has a higher discharge coefficient and a better cluster capacity. The nozzle with a throat length of 3 times the outlet diameter has a longer flow core. Considering the nozzle size, the nozzle with a converging angle of 15° and a throat length of 3 times the diameter of the outlet is suggested when the nozzle is used in jetting for obtaining a longer jetting distance.
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Good BC. The effects of non-Newtonian blood modeling and pulsatility on hemodynamics in the food and drug administration's benchmark nozzle model. Biorheology 2021:BIR201019. [PMID: 34924367 DOI: 10.3233/bir-201019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Computational fluid dynamics (CFD) is an important tool for predicting cardiovascular device performance. The FDA developed a benchmark nozzle model in which experimental and CFD data were compared, however, the studies were limited by steady flows and Newtonian models. OBJECTIVE Newtonian and non-Newtonian blood models will be compared under steady and pulsatile flows to evaluate their influence on hemodynamics in the FDA nozzle. METHODS CFD simulations were validated against the FDA data for steady flow with a Newtonian model. Further simulations were performed using Newtonian and non-Newtonian models under both steady and pulsatile flows. RESULTS CFD results were within the experimental standard deviations at nearly all locations and Reynolds numbers. The model differences were most evident at Re = 500, in the recirculation regions, and during diastole. The non-Newtonian model predicted blunter upstream velocity profiles, higher velocities in the throat, and differences in the recirculation flow patterns. The non-Newtonian model also predicted a greater pressure drop at Re = 500 with minimal differences observed at higher Reynolds numbers. CONCLUSIONS An improved modeling framework and validation procedure were used to further investigate hemodynamics in geometries relevant to cardiovascular devices and found that accounting for blood's non-Newtonian and pulsatile behavior can lead to large differences in predictions in hemodynamic parameters.
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Affiliation(s)
- Bryan C Good
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA
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Huo JD, Wu P, Zhang L, Wu WT. Large eddy simulation as a fast and accurate engineering approach for the simulation of rotary blood pumps. Int J Artif Organs 2021; 44:887-899. [PMID: 34474617 DOI: 10.1177/03913988211041636] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An accurate representation of the flow field in blood pumps is important for the design and optimization of blood pumps. The primary turbulence modeling methods applied to blood pumps have been the Reynolds-averaged Navier-Stokes (RANS) or URANS (unsteady RANS) method. Large eddy simulation (LES) method has been introduced to simulate blood pumps. Nonetheless, LES has not been widely used to assist in the design and optimization of blood pumps to date due to its formidable computational cost. The purpose of this study is to explore the potential of the LES technique as a fast and accurate engineering approach for the simulation of rotary blood pumps. The performance of "Light LES" (using the same time and spatial resolutions as the URANS) and LES in two rotary blood pumps was evaluated by comparing the results with the URANS and extensive experimental results. This study showed that the results of both "Light LES" and LES are superior to URANS, in terms of both performance curves and key flow features. URANS could not predict the flow separation and recirculation in diffusers for both pumps. In contrast, LES is superior to URANS in capturing these flows, performing well for both design and off-design conditions. The differences between the "Light LES" and LES results were relatively small. This study shows that with less computational cost than URANS, "Light LES" can be considered as a cost-effective engineering approach to assist in the design and optimization of rotary blood pumps.
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Affiliation(s)
- Jia-Dong Huo
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
| | - Peng Wu
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
| | - Liudi Zhang
- Artificial Organ Technology Laboratory, School of Mechanical and Electric Engineering, Soochow University, Suzhou, China
| | - Wei-Tao Wu
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, China
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14
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Yu Z, Tan J, Wang S. Enhanced discrete phase model for multiphase flow simulation of blood flow with high shear stress. Sci Prog 2021; 104:368504211008064. [PMID: 33788651 PMCID: PMC10358624 DOI: 10.1177/00368504211008064] [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] [Indexed: 11/15/2022]
Abstract
Shear stress is often present in the blood flow within blood-contacting devices, which is the leading cause of hemolysis. However, the simulation method for blood flow with shear stress is still not perfect, especially the multiphase flow model and experimental verification. In this regard, this study proposes an enhanced discrete phase model for multiphase flow simulation of blood flow with shear stress. This simulation is based on the discrete phase model (DPM). According to the multiphase flow characteristics of blood, a virtual mass force model and a pressure gradient influence model are added to the calculation of cell particle motion. In the experimental verification, nozzle models were designed to simulate the flow with shear stress, varying the degree of shear stress through different nozzle sizes. The microscopic flow was measured by the Particle Image Velocimetry (PIV) experimental method. The comparison of the turbulence models and the verification of the simulation accuracy were carried out based on the experimental results. The result demonstrates that the simulation effect of the SST k-ω model is better than other standard turbulence models. Accuracy analysis proves that the simulation results are accurate and can capture the movement of cell-level particles in the flow with shear stress. The results of the research are conducive to obtaining accurate and comprehensive analysis results in the equipment development phase.
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Affiliation(s)
- Zheqin Yu
- College of Energy and Power Engineering, Changsha University of Science & Technology, Hunan, China
- College of Mechanical and Electrical Engineering, Central South University, Changsha, Hunan, China
| | - Jianping Tan
- College of Mechanical and Electrical Engineering, Central South University, Changsha, Hunan, China
| | - Shuai Wang
- College of Mechanical and Electrical Engineering, Central South University, Changsha, Hunan, China
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15
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Flow Structures on a Planar Food and Drug Administration (FDA) Nozzle at Low and Intermediate Reynolds Number. FLUIDS 2020. [DOI: 10.3390/fluids6010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper, we present a general description of the flow structures inside a two-dimensional Food and Drug Administration (FDA) nozzle. To this aim, we have performed numerical simulations using the numerical code Nek5000. The topology patters of the solution obtained, identify four different flow regimes when the flow is steady, where the symmetry of the flow breaks down. An additional case has been studied at higher Reynolds number, when the flow is unsteady, finding a vortex street distributed along the expansion pipe of the geometry. Linear stability analysis identifies the evolution of two steady and two unsteady modes. The results obtained have been connected with the changes in the topology of the flow. Finally, higher-order dynamic mode decomposition has been applied to identify the main flow structures in the unsteady flow inside the FDA nozzle. The highest-amplitude dynamic mode decomposition (DMD) modes identified by the method model the vortex street in the expansion of the geometry.
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16
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Rezaeimoghaddam M, Oguz GN, Ates MS, Bozkaya TA, Piskin S, Samaneh Lashkarinia S, Tenekecioglu E, Karagoz H, Pekkan K. Patient-Specific Hemodynamics of New Coronary Artery Bypass Configurations. Cardiovasc Eng Technol 2020; 11:663-678. [PMID: 33051831 DOI: 10.1007/s13239-020-00493-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/01/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE This study aims to quantify the patient-specific hemodynamics of complex conduit routing configurations of coronary artery bypass grafting (CABG) operation which are specifically suitable for off-pump surgeries. Coronary perfusion efficacy and local hemodynamics of multiple left internal mammary artery (LIMA) with sequential and end-to-side anastomosis are investigated. Using a full anatomical model comprised of aortic arch and coronary artery branches the optimum perfusion configuration in multi-vessel coronary artery stenosis is desired. METHODOLOGY Two clinically relevant CABG configurations are created using a virtual surgical planning tool where for each configuration set, the stenosis level, anastomosis distance and angle were varied. A non-Newtonian computational fluid dynamics solver in OpenFOAM incorporated with resistance boundary conditions representing the coronary perfusion physiology was developed. The numerical accuracy is verified and results agreed well with a validated commercial cardiovascular flow solver and experiments. For segmental performance analysis, new coronary perfusion indices to quantify deviation from the healthy scenario were introduced. RESULTS The first simulation configuration set;-a CABG targeting two stenos sites on the left anterior descending artery (LAD), the LIMA graft was capable of 31 mL/min blood supply for all the parametric cases and uphold the healthy LAD perfusion in agreement with the clinical experience. In the second end-to-side anastomosed graft configuration set;-the radial artery graft anastomosed to LIMA, a maximum of 64 mL/min flow rate in LIMA was observed. However, except LAD, the obtuse marginal (OM) and second marginal artery (m2) suffered poor perfusion. In the first set, average wall shear stress (WSS) were in the range of 4 to 35 dyns/cm2 for in LAD. Nevertheless, for second configuration sets the WSS values were higher as the LIMA could not supply enough blood to OM and m2. CONCLUSION The virtual surgical configurations have the potential to improve the quality of operation by providing quantitative surgical insight. The degree of stenosis is a critical factor in terms of coronary perfusion and WSS. The sequential anastomosis can be done safely if the anastomosis angle is less than 90 degrees regardless of degree of stenosis. The smaller proposed perfusion index value, O(0.04 - 0) × 102, enable us to quantify the post-op hemodynamic performance by comparing with the ideal healthy physiological flow.
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Affiliation(s)
- Mohammad Rezaeimoghaddam
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey
| | - Gokce Nur Oguz
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey
| | - Mehmet Sanser Ates
- Department of Cardiovascular Surgery, Koc University Hospital, Topkapi, Istanbul, Turkey
| | - Tijen Alkan Bozkaya
- Department of Cardiovascular Surgery, Koc University Hospital, Topkapi, Istanbul, Turkey
| | - Senol Piskin
- Department of Mechanical Engineering, Istinye University, Zeytinburnu, Istanbul, Turkey
| | - S Samaneh Lashkarinia
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey
| | - Erhan Tenekecioglu
- Department of Cardiology, Health Sciences University, Bursa Education and Research Hospital, Bursa, Turkey
| | - Haldun Karagoz
- Department of Cardiovascular Surgery, VKV American Hospital, Istanbul, Turkey
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koc University, Rumeli Feneri Campus, Sariyer, Istanbul, Turkey.
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17
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Manchester EL, Xu XY. The effect of turbulence on transitional flow in the FDA's benchmark nozzle model using large-eddy simulation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3389. [PMID: 32738822 DOI: 10.1002/cnm.3389] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
The Food and Drug Administration's (FDA) benchmark nozzle model has been studied extensively both experimentally and computationally. Although considerable efforts have been made on validations of a variety of numerical models against available experimental data, the transitional flow cases are still not fully resolved, especially with regards to detailed comparison of predicted turbulence quantities with experimental measurements. This study aims to fill this gap by conducting large-eddy simulations (LES) of flow through the FDA's benchmark model, at a transitional Reynolds number of 2000. Numerical results are compared to previous interlaboratory experimental results, with an emphasis on turbulence characteristics. Our results show that the LES methodology can accurately capture laminar quantities throughout the model. In the pre-jet breakdown region, predicted turbulence quantities are generally larger than high resolution experimental data acquired with laser Doppler velocimetry. In the jet breakdown regions, where maximum Reynolds stresses occur, Reynolds shear stresses show excellent agreement. Differences of up to 4% and 20% are observed near the jet core in the axial and radial normal Reynolds stresses, respectively. Comparisons between viscous and Reynolds shear stresses show that peak viscous shear stresses occur in the nozzle throat reaching a value of 18 Pa in the boundary layer, whilst peak Reynolds shear stresses occur in the jet breakdown region reaching a maximum value of 87 Pa. Our results highlight the importance in considering both laminar and turbulent contributions towards shear stresses and that neglecting the turbulence effect can significantly underestimate the total shear force exerted on the fluid.
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Affiliation(s)
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
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18
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Chong A, Sun Z, van de Velde L, Jansen S, Versluis M, Reijnen MMPJ, Groot Jebbink E. A novel roller pump for physiological flow. Artif Organs 2020; 44:818-826. [DOI: https:/doi.org/10.1111/aor.13670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 02/10/2020] [Indexed: 11/30/2023]
Abstract
AbstractHaving physiological correct flow waveforms is a key feature for experimental studies of blood flow, especially in the process of developing and testing a new medical device such as stent, mechanical heart valve, or any implantable medical device that involves circulation of blood through the device. It is also a critical part of a perfusion system for cardiopulmonary bypass and extracorporeal membrane oxygenation procedures. This study investigated the feasibility of a novel roller pump for use in experimental flow phantoms. Flow rates of carotid flow profile measured directly with the ultrasonic flow meter matched well with the reference flow rates programmed into the machine with similarity index of 0.97 and measured versus programmed flow rates at specific time‐points of peak systolic velocity (PSV): 0.894 vs 0.880, end systolic velocity (ESV): 0.333 vs 0.319, and peak diastolic velocity (PDV): 0.514 vs 0.520 L/min. Flow rates derived from video analysis of the pump motion for carotid, suprarenal, and infrarenal flows also matched well with references with similarity indices of 0.99, 0.99, and 0.96, respectively. Measured flow rates (mean/standard deviation) at PSV, ESV, and PDV time‐points for carotid: 0.883/0.016 vs 0.880, 0.342/0.007 vs 0.319, and 0.485/0.009 vs 0.520; suprarenal: 3.497/0.014 vs 3.500, 0.004/0.003 vs 0, and 1.656/0.073 vs 1.453; infrarenal: 4.179/0.024 vs 4.250, −1.147/0.015 vs −1.213, and 0.339/0.017 vs 0.391 L/min, respectively. The novel roller pump is suitable for benchtop testing of physiological flow.
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Affiliation(s)
- Albert Chong
- Department of Medical Radiation Sciences Curtin University Perth WA Australia
| | - Zhonghua Sun
- Department of Medical Radiation Sciences Curtin University Perth WA Australia
| | - Lennart van de Velde
- Multi‐Modality Medical Imaging (M3I) Group, Technical Medical Centre University of Twente Enschede The Netherlands
- Department of Surgery Rijnstate Arnhem The Netherlands
- Physics of Fluids Group, TechMed Center and MESA+ Institute for Nanotechnology University of Twente Enschede The Netherlands
| | - Shirley Jansen
- Department of Vascular and Endovascular Surgery Sir Charles Gairdner Hospital Perth WA Australia
- Department of Vascular Surgery Curtin University Perth WA Australia
- Faculty of Health and Medical Sciences University of Western Australia Perth WA Australia
- Heart and Vascular Research Institute Harry Perkins Institute of Medical Research Perth WA Australia
| | - Michel Versluis
- Multi‐Modality Medical Imaging (M3I) Group, Technical Medical Centre University of Twente Enschede The Netherlands
- Physics of Fluids Group, TechMed Center and MESA+ Institute for Nanotechnology University of Twente Enschede The Netherlands
| | - Michel M. P. J. Reijnen
- Multi‐Modality Medical Imaging (M3I) Group, Technical Medical Centre University of Twente Enschede The Netherlands
- Department of Surgery Rijnstate Arnhem The Netherlands
| | - Erik Groot Jebbink
- Multi‐Modality Medical Imaging (M3I) Group, Technical Medical Centre University of Twente Enschede The Netherlands
- Department of Surgery Rijnstate Arnhem The Netherlands
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19
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Jain K. Efficacy of the FDA nozzle benchmark and the lattice Boltzmann method for the analysis of biomedical flows in transitional regime. Med Biol Eng Comput 2020; 58:1817-1830. [PMID: 32507933 PMCID: PMC7340647 DOI: 10.1007/s11517-020-02188-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/08/2020] [Indexed: 12/22/2022]
Abstract
Flows through medical devices as well as in anatomical vessels despite being at moderate Reynolds number may exhibit transitional or even turbulent character. In order to validate numerical methods and codes used for biomedical flow computations, the US Food and Drug Administration (FDA) established an experimental benchmark, which was a pipe with gradual contraction and sudden expansion representing a nozzle. The experimental results for various Reynolds numbers ranging from 500 to 6500 were publicly released. Previous and recent computational investigations of flow in the FDA nozzle found limitations in various CFD approaches and some even questioned the adequacy of the benchmark itself. This communication reports the results of a lattice Boltzmann method (LBM) – based direct numerical simulation (DNS) approach applied to the FDA nozzle benchmark for transitional cases of Reynolds numbers 2000 and 3500. The goal is to evaluate if a simple off the shelf LBM would predict the experimental results without the use of complex models or synthetic turbulence at the inflow. LBM computations with various spatial and temporal resolutions are performed—in the extremities of 45 million to 2.88 billion lattice cells—executed respectively on 32 CPU cores of a desktop to more than 300,000 cores of a modern supercomputer to explore and characterize miniscule flow details and quantify Kolmogorov scales. The LBM simulations transition to turbulence at a Reynolds number 2000 like the FDA’s experiments and acceptable agreement in jet breakdown locations, average velocity, shear stress, and pressure is found for both the Reynolds numbers. A bisecting plane showing the FDA nozzle and vorticity magnitude at t = 10 s for throat Reynolds numbers of 2000 and 3500 ![]()
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Affiliation(s)
- Kartik Jain
- Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500AE, Enschede, The Netherlands.
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20
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Atif R, Combrinck M, Khaliq J, Hassanin AH, Shehata N, Elnabawy E, Shyha I. Solution Blow Spinning of High-Performance Submicron Polyvinylidene Fluoride Fibres: Computational Fluid Mechanics Modelling and Experimental Results. Polymers (Basel) 2020; 12:polym12051140. [PMID: 32429457 PMCID: PMC7284647 DOI: 10.3390/polym12051140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 11/16/2022] Open
Abstract
Computational fluid dynamics (CFD) was used to investigate characteristics of high-speed air as it is expelled from a solution blow spinning (SBS) nozzle using a k-ε turbulence model. Air velocity, pressure, temperature, turbulent kinetic energy and density contours were generated and analysed in order to achieve an optimal attenuation force for fibre production. A bespoke convergent nozzle was used to produce polyvinylidene fluoride (PVDF) fibres at air pressures between 1 and 5 bar. The nozzle comprised of four parts: a polymer solution syringe holder, an air inlet, an air chamber, and a cap that covers the air chamber. A custom-built SBS setup was used to produce PVDF submicron fibres which were consequently analysed using scanning electron microscope (SEM) for their morphological features. Both theoretical and experimental observations showed that a higher air pressure (4 bar) is more suitable to achieve thin fibres of PVDF. However, fibre diameter increased at 5 bar and intertwined ropes of fibres were also observed.
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Affiliation(s)
- Rasheed Atif
- Department of Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UK; (M.C.); (J.K.); (I.S.)
- Correspondence: ; Tel.: +44-(0)-191-227-3062
| | - Madeleine Combrinck
- Department of Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UK; (M.C.); (J.K.); (I.S.)
| | - Jibran Khaliq
- Department of Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UK; (M.C.); (J.K.); (I.S.)
| | - Ahmed H. Hassanin
- Centre of Smart Nanotechnology and Photonics (CSNP), SmartCI Research Center, Alexandria University, Alexandria 21544, Egypt; (A.H.H.); (N.S.); (E.E.)
- Department of Textile Engineering, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt
| | - Nader Shehata
- Centre of Smart Nanotechnology and Photonics (CSNP), SmartCI Research Center, Alexandria University, Alexandria 21544, Egypt; (A.H.H.); (N.S.); (E.E.)
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt
- USTAR Bioinnovations Centre, Faculty of Science, Utah State University, Logan, UT 84341, USA
- Kuwait College of Science and Technology (KCST), Doha District 13133, Kuwait
| | - Eman Elnabawy
- Centre of Smart Nanotechnology and Photonics (CSNP), SmartCI Research Center, Alexandria University, Alexandria 21544, Egypt; (A.H.H.); (N.S.); (E.E.)
| | - Islam Shyha
- Department of Mechanical and Construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, UK; (M.C.); (J.K.); (I.S.)
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21
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Large-Eddy Simulations of Flow in the FDA Benchmark Nozzle Geometry to Predict Hemolysis. Cardiovasc Eng Technol 2020; 11:254-267. [PMID: 32297154 DOI: 10.1007/s13239-020-00461-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 03/29/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE Modeling of hemolysis due to fluid stresses faces significant methodological challenges, particularly in geometries with turbulence or complex flow patterns. It is currently unclear how existing phenomenological blood-damage models based on laminar viscous stresses can be implemented into turbulent computational fluid dynamics simulations. The aim of this work is to generalize the existing laminar models to turbulent flows based on first principles, and validate this generalization with existing experimental data. METHODS A novel analytical and numerical framework for the simulation of flow-induced hemolysis based on the intermittency-corrected turbulent viscous shear stress (ICTVSS) is introduced. The proposed large-eddy simulation framework is able to seamlessly transition from laminar to turbulent conditions in a single flow domain by linking laminar shear stresses to dissipation of mechanical energy, accounting for intermittency in turbulent dissipation, and relying on existing power-law hemolysis models. Simulations are run to reproduce previously published hemolysis data with bovine blood in a benchmark geometry. Two sets of experimental data are relied upon to tune power-law parameters and justify that tuning. The first presents hemolysis measurements in a simple laminar flow, and the second is hemolysis in turbulent flow through the FDA benchmark nozzle. Validation is performed by simulation of blood injected into a turbulent jet of phosphate-buffered saline, with modifications made to account for the local concentration of blood. RESULTS Hemolysis predictions are found to be very sensitive to power-law parameters in the turbulent case, though a set of parameters is presented that both matches the turbulent data and is well-justified by the laminar data. The model is shown to be able to predict the general behavior of hemolysis in a second turbulent case. Results suggest that wall shear may play a dominant role in most cases. CONCLUSION The ICTVSS framework of generalizing laminar power-law models to turbulent flows shows promise, but would benefit from further numerical validation and carefully designed experiments.
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22
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Chong A, Sun Z, van de Velde L, Jansen S, Versluis M, Reijnen MMPJ, Groot Jebbink E. A novel roller pump for physiological flow. Artif Organs 2020; 44:818-826. [PMID: 32065666 PMCID: PMC7496437 DOI: 10.1111/aor.13670] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/28/2020] [Accepted: 02/10/2020] [Indexed: 01/24/2023]
Abstract
Having physiological correct flow waveforms is a key feature for experimental studies of blood flow, especially in the process of developing and testing a new medical device such as stent, mechanical heart valve, or any implantable medical device that involves circulation of blood through the device. It is also a critical part of a perfusion system for cardiopulmonary bypass and extracorporeal membrane oxygenation procedures. This study investigated the feasibility of a novel roller pump for use in experimental flow phantoms. Flow rates of carotid flow profile measured directly with the ultrasonic flow meter matched well with the reference flow rates programmed into the machine with similarity index of 0.97 and measured versus programmed flow rates at specific time‐points of peak systolic velocity (PSV): 0.894 vs 0.880, end systolic velocity (ESV): 0.333 vs 0.319, and peak diastolic velocity (PDV): 0.514 vs 0.520 L/min. Flow rates derived from video analysis of the pump motion for carotid, suprarenal, and infrarenal flows also matched well with references with similarity indices of 0.99, 0.99, and 0.96, respectively. Measured flow rates (mean/standard deviation) at PSV, ESV, and PDV time‐points for carotid: 0.883/0.016 vs 0.880, 0.342/0.007 vs 0.319, and 0.485/0.009 vs 0.520; suprarenal: 3.497/0.014 vs 3.500, 0.004/0.003 vs 0, and 1.656/0.073 vs 1.453; infrarenal: 4.179/0.024 vs 4.250, −1.147/0.015 vs −1.213, and 0.339/0.017 vs 0.391 L/min, respectively. The novel roller pump is suitable for benchtop testing of physiological flow.
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Affiliation(s)
- Albert Chong
- Department of Medical Radiation Sciences, Curtin University, Perth, WA, Australia
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, WA, Australia
| | - Lennart van de Velde
- Multi-Modality Medical Imaging (M3I) Group, Technical Medical Centre, University of Twente, Enschede, The Netherlands.,Department of Surgery, Rijnstate, Arnhem, The Netherlands.,Physics of Fluids Group, TechMed Center and MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
| | - Shirley Jansen
- Department of Vascular and Endovascular Surgery, Sir Charles Gairdner Hospital, Perth, WA, Australia.,Department of Vascular Surgery, Curtin University, Perth, WA, Australia.,Faculty of Health and Medical Sciences, University of Western Australia, Perth, WA, Australia.,Heart and Vascular Research Institute, Harry Perkins Institute of Medical Research, Perth, WA, Australia
| | - Michel Versluis
- Multi-Modality Medical Imaging (M3I) Group, Technical Medical Centre, University of Twente, Enschede, The Netherlands.,Physics of Fluids Group, TechMed Center and MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
| | - Michel M P J Reijnen
- Multi-Modality Medical Imaging (M3I) Group, Technical Medical Centre, University of Twente, Enschede, The Netherlands.,Department of Surgery, Rijnstate, Arnhem, The Netherlands
| | - Erik Groot Jebbink
- Multi-Modality Medical Imaging (M3I) Group, Technical Medical Centre, University of Twente, Enschede, The Netherlands.,Department of Surgery, Rijnstate, Arnhem, The Netherlands
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23
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Nikfar M, Razizadeh M, Zhang J, Paul R, Wu ZJ, Liu Y. Prediction of mechanical hemolysis in medical devices via a Lagrangian strain-based multiscale model. Artif Organs 2020; 44:E348-E368. [PMID: 32017130 DOI: 10.1111/aor.13663] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/22/2019] [Accepted: 01/31/2020] [Indexed: 01/25/2023]
Abstract
This work introduces a new Lagrangian strain-based model to predict the shear-induced hemolysis in biomedical devices. Current computational models for device-induced hemolysis usually utilize empirical fitting of the released free hemoglobin (Hb) in plasma from damaged red blood cells (RBCs). These empirical correlations contain parameters that depend on specific device and operating conditions, thus cannot be used to predict hemolysis in a general device. The proposed algorithm does not have any empirical parameters, thus can presumably be used for hemolysis prediction in various blood-wetting medical devices. In contrast to empirical correlations in which the Hb release is related to the shear stress and exposure time without considering the physical processes, the proposed model links flow-induced deformation of the RBC membrane to membrane permeabilization and Hb release. In this approach, once the steady-state numerical solution of blood flow in the device is obtained under a prescribed operating condition, sample path lines are traced from the inlet of the device to the outlet to calculate the history of the shear stress tensor. In solving the fluid flow, it is assumed that RBCs do not have any influence on the flow pattern. Along each path line, shear stress tensor will be input into a coarse-grained (CG) RBC model to calculate the RBC deformation. Then the correlations obtained from molecular dynamics (MD) simulations are applied to relate the local areal RBC deformation to the perforated area on the RBC membrane. Finally, Hb released out of transient pores is calculated over each path line via a diffusion equation considering the effects of the steric hindrance and increased hydrodynamic drag due to the size of the Hb molecule. The total index of hemolysis (IH) is calculated by integration of released Hb over all the path lines in the computational domain. Hemolysis generated in the Food and Drug Administration (FDA) nozzle and two blood pumps, that is, a CentriMag blood pump (a centrifugal pump) and HeartMate II (an axial pump), for different flow regimes including the laminar and turbulent flows are calculated via the proposed algorithm. In all the simulations, the numerical predicted IH is close to the range of experimental data. The results promisingly indicate that this multiscale approach can be used as a tool for predicting hemolysis and optimizing the hematologic design of other types of blood-wetting devices.
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Affiliation(s)
- Mehdi Nikfar
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA
| | - Meghdad Razizadeh
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA
| | - Jiafeng Zhang
- Department of Surgery, University of Maryland, School of Medicine, Baltimore, MD, USA
| | - Ratul Paul
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA
| | - Zhongjun J Wu
- Department of Surgery, University of Maryland, School of Medicine, Baltimore, MD, USA
| | - Yaling Liu
- Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA, USA.,Department of Bioengineering, Lehigh University, Bethlehem, PA, USA
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24
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YU ZHEQIN, TAN JIANPIN, WANG SHUAI. MODIFICATION OF THE SPALART–ALLMARAS MODEL FOR HEMOLYTIC SHEAR FLOW SIMULATION WITH PIV EXPERIMENT. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420500025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Hemolysis in blood-contacting devices severely affects the health of users, and computation fluid dynamics (CFD) simulation is a crucial method for hemolysis analysis. Medical equipment has high requirements for simulation accuracy. Modification of the turbulence model is one of the most effective ways to improve efficiency. In this study, we designed nozzle models to simulate hemolytic shear flow, varying the degree of shear flow through different nozzle orifice sizes. The study acquires microscopic flow results through Particle Image Velocimetry (PIV) experiments, and the Sparlart–Allmaras (S–A) model was modified based on the experimental results. In the study, we obtained the influence characteristics of the model coefficients on the simulation results and completed the accuracy correction. The results showed that the model coefficient [Formula: see text] has the most significant effect on the simulation results. Correcting [Formula: see text] to about 200% of the standard value can significantly improve the simulation accuracy, and the high shear flow intensity corresponds to a slightly lower correction value. The model modification eliminates the simulation error in the high-speed area, and the comparison results show that it is superior to the standard turbulence model.
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Affiliation(s)
- ZHEQIN YU
- School of Mechanical and Electrical Engineering, Central South University, Hunan 410083, P. R. China
| | - JIANPIN TAN
- School of Mechanical and Electrical Engineering, Central South University, Hunan 410083, P. R. China
| | - SHUAI WANG
- School of Mechanical and Electrical Engineering, Central South University, Hunan 410083, P. R. China
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Good BC, Manning KB. Computational modeling of the Food and Drug Administration's benchmark centrifugal blood pump. Artif Organs 2020; 44:E263-E276. [PMID: 31971269 DOI: 10.1111/aor.13643] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
In order to simulate hemodynamics within centrifugal blood pumps and to predict pump hemolysis, CFD simulations must be thoroughly validated against experimental data. They must also account for and accurately model the specific working fluid in the pump, whether that is a blood-analog solution to match an experimental PIV study or animal blood in a hemolysis experiment. Therefore, the Food and Drug Administration (FDA) benchmark centrifugal blood pump and its database of experimental PIV and hemolysis data were used to thoroughly validate CFD simulations of the same blood pump. A Newtonian blood model was first used to compare to the PIV data with a blood analog fluid while hemolysis data were compared using a power-law hemolysis model fit to porcine blood data. A viscoelastic blood model was then incorporated into the CFD solver to investigate the importance of modeling blood's viscoelasticity in centrifugal pumps. The established computational framework, including a dynamic rotating mesh, animal blood-specific fluid properties and hemolysis modeling, and a k-ω SST turbulence model, was shown to more accurately predict pump pressure heads, velocity fields, and hemolysis compared to previously published CFD studies of the FDA centrifugal pump. The CFD simulations were able to match the FDA pressure and hemolysis data for multiple pump operating conditions, with the CFD results being within the standard deviations of the experimental results. While CFD radial velocity profiles between the impeller blades also compared well to the PIV velocity results, more work is still needed to address the large variability among both experimental and computational predictions of velocity in the diffuser outlet jet. Small differences were observed between the Newtonian and viscoelastic blood models in pressure head and hemolysis at the higher flow rate cases (FDA Conditions 4 and 5) but were more significant at lower flow rate and pump impeller speeds (FDA Condition 1). These results suggest that the importance of accounting for blood's viscoelasticity may be dependent on the specific blood pump operating conditions. This detailed computational framework with improved modeling techniques and an extensive validation procedure will be used in future CFD studies of centrifugal blood pumps to aid in device design and predictions of their biological responses.
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Affiliation(s)
- Bryan C Good
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA.,Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA
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Fehn N, Wall WA, Kronbichler M. Modern discontinuous Galerkin methods for the simulation of transitional and turbulent flows in biomedical engineering: A comprehensive LES study of the FDA benchmark nozzle model. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3228. [PMID: 31232525 DOI: 10.1002/cnm.3228] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 06/11/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
This work uses high-order discontinuous Galerkin discretization techniques to simulate transitional and turbulent flows through medical devices. Flows through medical devices are characterized by moderate Reynolds numbers and typically involve different flow regimes such as laminar, transitional, and turbulent flows. Previous studies for the FDA benchmark nozzle model revealed limitations of Reynolds-averaged Navier-Stokes turbulence models when applied to more complex flow scenarios. Recent works based on large-eddy simulation approaches indicate that these limitations can be overcome but also highlight potential limitations due to a high sensitivity with respect to numerical parameters. The methodology presented in this work introduces two novel ingredients compared with previous studies. Firstly, we use high-order discontinuous Galerkin methods for discretization in space. The inherent dissipation and dispersion properties of high-order discontinuous Galerkin discretizations are expected to render this approach well suited for transitional and turbulent flow simulations. Secondly, to mimic blinded CFD studies, we propose to use a precursor simulation approach in order to predict the inflow boundary condition for laminar, transitional, and turbulent flow regimes instead of prescribing analytical velocity profiles at the inflow. We investigate the whole range of Reynolds numbers as suggested by the FDA benchmark nozzle problem and compare the numerical results to experimental data obtained by particle image velocimetry in order to critically assess the predictive capabilities of the solver on the one hand and the suitability of the FDA nozzle problem as a benchmark in computational fluid dynamics on the other hand.
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Affiliation(s)
- Niklas Fehn
- Institute for Computational Mechanics, Technical University of Munich, Munich, Germany
| | - Wolfgang A Wall
- Institute for Computational Mechanics, Technical University of Munich, Munich, Germany
| | - Martin Kronbichler
- Institute for Computational Mechanics, Technical University of Munich, Munich, Germany
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Wu P, Groß-Hardt S, Boehning F, Hsu PL. An energy-dissipation-based power-law formulation for estimating hemolysis. Biomech Model Mechanobiol 2019; 19:591-602. [DOI: 10.1007/s10237-019-01232-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 10/09/2019] [Indexed: 11/27/2022]
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28
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Non-physiological shear stress-induced blood damage in ventricular assist device. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Nicoud F, Zmijanovic V, Mendez S. Reaching a good agreement between computational hemodynamics results and in vitro data is not enough. Comput Methods Biomech Biomed Engin 2019. [DOI: 10.1080/10255842.2020.1713486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- F. Nicoud
- IMAG, Univ Montpellier, CNRS, Montpellier, France
| | | | - S. Mendez
- IMAG, Univ Montpellier, CNRS, Montpellier, France
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Wu P, Gao Q, Hsu PL. On the representation of effective stress for computing hemolysis. Biomech Model Mechanobiol 2019; 18:665-679. [DOI: 10.1007/s10237-018-01108-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 12/15/2018] [Indexed: 11/29/2022]
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Gallagher MB, Aycock KI, Craven BA, Manning KB. Steady Flow in a Patient-Averaged Inferior Vena Cava-Part I: Particle Image Velocimetry Measurements at Rest and Exercise Conditions. Cardiovasc Eng Technol 2018; 9:641-653. [PMID: 30411228 PMCID: PMC10508872 DOI: 10.1007/s13239-018-00390-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 10/19/2018] [Indexed: 12/23/2022]
Abstract
PURPOSE Although many previous computational fluid dynamics (CFD) studies have investigated the hemodynamics in the inferior vena cava (IVC), few studies have compared computational predictions to experimental data, and only qualitative comparisons have been made. Herein, we provide particle image velocimetry (PIV) measurements of flow in a patient-averaged IVC geometry under idealized conditions typical of those used in the preclinical evaluation of IVC filters. METHODS Measurements are acquired under rest and exercise flow rate conditions in an optically transparent model fabricated using 3D printing. To ensure that boundary conditions are well-defined and to make follow-on CFD validation studies more convenient, fully-developed flow is provided at the inlets (i.e., the iliac veins) by extending them with straight rigid tubing longer than the estimated entrance lengths. Velocity measurements are then obtained at the downstream end of the tubing to confirm Poiseuille inflow boundary conditions. RESULTS Measurements in the infrarenal IVC reveal that flow profiles are blunter in the sagittal plane (minor axis) than in the coronal plane (major axis). Peak in-plane velocity magnitudes are 4.9 cm/s and 27 cm/s under the rest and exercise conditions, respectively. Flow profiles are less parabolic and exhibit more inflection points at the higher flow rate. Bimodal velocity peaks are also observed in the sagittal plane at the elevated flow condition. CONCLUSIONS The IVC geometry, boundary conditions, and infrarenal velocity measurements are provided for download on a free and publicly accessible repository at https://doi.org/10.6084/m9.figshare.7198703 . These data will facilitate future CFD validation studies of idealized, in vitro IVC hemodynamics and of similar laminar flows in vascular geometries.
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Affiliation(s)
- Maureen B Gallagher
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Kenneth I Aycock
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, USA
| | - Brent A Craven
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, United States Food and Drug Administration, Silver Spring, MD, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA.
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA.
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Inter-Laboratory Characterization of the Velocity Field in the FDA Blood Pump Model Using Particle Image Velocimetry (PIV). Cardiovasc Eng Technol 2018; 9:623-640. [DOI: 10.1007/s13239-018-00378-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/08/2018] [Indexed: 12/12/2022]
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33
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Hariharan P, Paruchuri SS, Topoleski LDT, Rinaldi JE, Casamento JP, Myers MR, Vesnovsky O. A test method to assess the contribution of fluid shear stress to the cleaning of reusable device surfaces. J Biomed Mater Res B Appl Biomater 2018; 107:1132-1140. [PMID: 30184332 DOI: 10.1002/jbm.b.34206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 06/27/2018] [Accepted: 06/28/2018] [Indexed: 01/18/2023]
Abstract
Adequate cleaning of reusable medical devices is critical for preventing cross-infection among patients. For reusable medical devices, cleaning using mechanical brushes and detergent may not be sufficient to completely remove the infectious contaminants from the surfaces. This study evaluates the role of fluid flow-induced shear stress in the detachment and removal of contaminants from device surfaces. A stainless-steel test coupon, acting as a surrogate for a device surface, was coated with artificial clot of varying mass. The test coupon was exposed to fluid shear stress both with and without an enzymatic detergent. The relationship between clot removal quantity and the applied shear stress was obtained for multiple clot masses. Our results showed that fluid shear increased the effectiveness of the cleaning process. In the absence of flow, soaking the clot surface in the enzymatic detergent removed 67%, 77%, and 95% of the clot for 16 mg, 6.8 mg, and 1 mg initial masses, respectively. In the presence of fluid shear (0.3 Pa for 5 min), approximately 85%, 97%, and 99% of the clot was removed from the surface. The clot mass removed followed a linear relationship (R2 = 0.98) versus the applied fluid shear stress. This study showed that different cleaning processes such as fluid shear and detergent action contribute to the soil removal process. This method could be used to evaluate cleaning protocols for minimizing contaminant residue after the reprocessing of medical devices. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1132-1140, 2019.
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Affiliation(s)
- Prasanna Hariharan
- Division of Applied Mechanics, Center for Devices and Radiological length (CDRH), US FDA, Silver Spring, MD, United States
| | - Sai Sameer Paruchuri
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, United States
| | - L D Timmie Topoleski
- Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, Maryland, United States
| | - Jean E Rinaldi
- Division of Applied Mechanics, Center for Devices and Radiological length (CDRH), US FDA, Silver Spring, MD, United States
| | - Jon P Casamento
- Division of Applied Mechanics, Center for Devices and Radiological length (CDRH), US FDA, Silver Spring, MD, United States
| | - Matthew R Myers
- Division of Applied Mechanics, Center for Devices and Radiological length (CDRH), US FDA, Silver Spring, MD, United States
| | - Oleg Vesnovsky
- Division of Applied Mechanics, Center for Devices and Radiological length (CDRH), US FDA, Silver Spring, MD, United States
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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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35
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36
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Paliwal N, Damiano RJ, Varble NA, Tutino VM, Dou Z, Siddiqui AH, Meng H. Methodology for Computational Fluid Dynamic Validation for Medical Use: Application to Intracranial Aneurysm. J Biomech Eng 2017; 139:2653365. [PMID: 28857116 PMCID: PMC5686786 DOI: 10.1115/1.4037792] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 08/28/2017] [Indexed: 11/08/2022]
Abstract
Computational fluid dynamics (CFD) is a promising tool to aid in clinical diagnoses of cardiovascular diseases. However, it uses assumptions that simplify the complexities of the real cardiovascular flow. Due to high-stakes in the clinical setting, it is critical to calculate the effect of these assumptions in the CFD simulation results. However, existing CFD validation approaches do not quantify error in the simulation results due to the CFD solver's modeling assumptions. Instead, they directly compare CFD simulation results against validation data. Thus, to quantify the accuracy of a CFD solver, we developed a validation methodology that calculates the CFD model error (arising from modeling assumptions). Our methodology identifies independent error sources in CFD and validation experiments, and calculates the model error by parsing out other sources of error inherent in simulation and experiments. To demonstrate the method, we simulated the flow field of a patient-specific intracranial aneurysm (IA) in the commercial CFD software star-ccm+. Particle image velocimetry (PIV) provided validation datasets for the flow field on two orthogonal planes. The average model error in the star-ccm+ solver was 5.63 ± 5.49% along the intersecting validation line of the orthogonal planes. Furthermore, we demonstrated that our validation method is superior to existing validation approaches by applying three representative existing validation techniques to our CFD and experimental dataset, and comparing the validation results. Our validation methodology offers a streamlined workflow to extract the "true" accuracy of a CFD solver.
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Affiliation(s)
- Nikhil Paliwal
- Department of Mechanical and Aerospace Engineering,
University at Buffalo,
Buffalo, NY 14260
- Toshiba Stroke and Vascular Research Center,
University at Buffalo,
Buffalo, NY 14203
| | - Robert J. Damiano
- Department of Mechanical and Aerospace Engineering,
University at Buffalo,
Buffalo, NY 14260
- Toshiba Stroke and Vascular Research Center,
University at Buffalo,
Buffalo, NY 14203
| | - Nicole A. Varble
- Department of Mechanical and Aerospace Engineering,
University at Buffalo,
Buffalo, NY 14260
- Toshiba Stroke and Vascular Research Center,
University at Buffalo,
Buffalo, NY 14203
| | - Vincent M. Tutino
- Toshiba Stroke and Vascular Research Center,
University at Buffalo,
Buffalo, NY 14203
- Department of Biomedical Engineering,
University at Buffalo,
Buffalo, NY 14260
| | - Zhongwang Dou
- Department of Mechanical and Aerospace Engineering,
University at Buffalo,
Buffalo, NY 14260
| | - Adnan H. Siddiqui
- Toshiba Stroke and Vascular Research Center,
University at Buffalo,
Buffalo, NY 14260
- Department of Neurosurgery,
University at Buffalo,
Buffalo, NY 14226
| | - Hui Meng
- Department of Mechanical and Aerospace Engineering,
University at Buffalo,
324 Jarvis Hall,
Buffalo, NY 14260
- Toshiba Stroke and Vascular Research Center,
University at Buffalo,
Buffalo, NY 14203
- Department of Biomedical Engineering,
University at Buffalo,
Buffalo, NY 14260
- Department of Neurosurgery,
University at Buffalo,
Buffalo, NY 14226
e-mail:
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Wang Y, Quaini A, Čanić S, Vukicevic M, Little SH. 3D Experimental and Computational Analysis of Eccentric Mitral Regurgitant Jets in a Mock Imaging Heart Chamber. Cardiovasc Eng Technol 2017; 8:419-438. [PMID: 28695443 DOI: 10.1007/s13239-017-0316-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 06/24/2017] [Indexed: 11/24/2022]
Abstract
Mitral valve regurgitation (MR) is a disorder of the heart in which the mitral valve does not close properly. This causes an abnormal leaking of blood backwards from the left ventricle into the left atrium during the systolic contractions of the left ventricle. Noninvasive assessment of MR using echocardiography is an ongoing challenge. In particular, a major problem are eccentric or Coanda regurgitant jets which hug the walls of the left atrium and appear smaller in the color Doppler image of regurgitant flow. This manuscript presents a comprehensive investigation of Coanda regurgitant jets and the associated intracardiac flows by using a combination of experimental and computational approaches. An anatomically correct mock heart chamber connected to a pulsatile flow loop is used to generate the physiologically relevant flow conditions, and the influence of two clinically relevant parameters (orifice aspect ratio and regurgitant volume) on the onset of Coanda effect is studied. A two parameter bifurcation diagram showing transition to Coanda jets is obtained, indicating that: (1) strong wall hugging jets occur in long and narrow orifices with moderate to large regurgitant volumes, and (2) short orifices with moderate to large regurgitant volumes produce strong 3D flow features such as vortex rolls, giving rise to the velocities that are orthogonal to the 2D plane associated with the apical color Doppler views, making them "invisible" to the single plane color Doppler assessment of MR. This is the first work in which the presence of vortex rolls in the left atrium during regurgitation is reported and identified as one of the reasons for under-estimation of regurgitant volume. The results of this work can be used for better design of imaging strategies in noninvasive assessment of MR, and for better understanding of LA remodeling that may be associated with the presence of maladapted vortex dynamics. This introduces a new concept in clinical imaging, which emphasizes that the quality and not only the quantity of regurgitant flow matters in the assessment of severity of mitral valve regurgitation.
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Affiliation(s)
- Yifan Wang
- Department of Mathematics, University of Houston, 4800 Calhoun Rd, Houston, TX, 77204, USA
| | - Annalisa Quaini
- Department of Mathematics, University of Houston, 4800 Calhoun Rd, Houston, TX, 77204, USA.
| | - Sunčica Čanić
- Department of Mathematics, University of Houston, 4800 Calhoun Rd, Houston, TX, 77204, USA
| | - Marija Vukicevic
- The Methodist Hospital Houston, 6550 Fannin Suite 1901, Houston, TX, 77030, USA
| | - Stephen H Little
- The Methodist Hospital Houston, 6550 Fannin Suite 1901, Houston, TX, 77030, USA
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Hariharan P, D’Souza GA, Horner M, Morrison TM, Malinauskas RA, Myers MR. Use of the FDA nozzle model to illustrate validation techniques in computational fluid dynamics (CFD) simulations. PLoS One 2017; 12:e0178749. [PMID: 28594889 PMCID: PMC5464577 DOI: 10.1371/journal.pone.0178749] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 05/18/2017] [Indexed: 12/14/2022] Open
Abstract
A "credible" computational fluid dynamics (CFD) model has the potential to provide a meaningful evaluation of safety in medical devices. One major challenge in establishing "model credibility" is to determine the required degree of similarity between the model and experimental results for the model to be considered sufficiently validated. This study proposes a "threshold-based" validation approach that provides a well-defined acceptance criteria, which is a function of how close the simulation and experimental results are to the safety threshold, for establishing the model validity. The validation criteria developed following the threshold approach is not only a function of Comparison Error, E (which is the difference between experiments and simulations) but also takes in to account the risk to patient safety because of E. The method is applicable for scenarios in which a safety threshold can be clearly defined (e.g., the viscous shear-stress threshold for hemolysis in blood contacting devices). The applicability of the new validation approach was tested on the FDA nozzle geometry. The context of use (COU) was to evaluate if the instantaneous viscous shear stress in the nozzle geometry at Reynolds numbers (Re) of 3500 and 6500 was below the commonly accepted threshold for hemolysis. The CFD results ("S") of velocity and viscous shear stress were compared with inter-laboratory experimental measurements ("D"). The uncertainties in the CFD and experimental results due to input parameter uncertainties were quantified following the ASME V&V 20 standard. The CFD models for both Re = 3500 and 6500 could not be sufficiently validated by performing a direct comparison between CFD and experimental results using the Student's t-test. However, following the threshold-based approach, a Student's t-test comparing |S-D| and |Threshold-S| showed that relative to the threshold, the CFD and experimental datasets for Re = 3500 were statistically similar and the model could be considered sufficiently validated for the COU. However, for Re = 6500, at certain locations where the shear stress is close the hemolysis threshold, the CFD model could not be considered sufficiently validated for the COU. Our analysis showed that the model could be sufficiently validated either by reducing the uncertainties in experiments, simulations, and the threshold or by increasing the sample size for the experiments and simulations. The threshold approach can be applied to all types of computational models and provides an objective way of determining model credibility and for evaluating medical devices.
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Affiliation(s)
- Prasanna Hariharan
- US Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
| | - Gavin A. D’Souza
- US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Marc Horner
- ANSYS, Inc., Evanston, Illinois, United States of America
| | - Tina M. Morrison
- US Food and Drug Administration, Silver Spring, Maryland, United States of America
| | | | - Matthew R. Myers
- US Food and Drug Administration, Silver Spring, Maryland, United States of America
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40
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41
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Zmijanovic V, Mendez S, Moureau V, Nicoud F. About the numerical robustness of biomedical benchmark cases: Interlaboratory FDA's idealized medical device. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e02789. [PMID: 27021351 DOI: 10.1002/cnm.2789] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 06/05/2023]
Abstract
The need for reliable approaches in numerical simulations stands out as a critical issue for the development and optimization of cardiovascular biomedical devices. This led the US Food and Drug Administration to undertake a programme of validation of computational fluid dynamics methods for transitional and turbulent flows. In the current investigation, large-eddy simulation is used to simulate the flow in the first benchmark medical device, and results are confronted to the existing laboratory experiments. This idealized medical device has the particularity to feature transition to turbulence after a sudden expansion. The effects of numerical parameters and low-level inlet perturbations are investigated. Results indicate a considerable impact of numerical aspects on the prediction of the location of the transition to turbulence. The study also demonstrates that injecting small perturbations at the inflow greatly improves the streamwise velocity estimation in the transition region and substantially contributes to the robustness of the flow statistical data. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Vladeta Zmijanovic
- Institute of Montpellier Alexander Grothendieck - CNRS UMR5149 and University of Montpellier, Montpellier, 34095, France
| | - Simon Mendez
- Institute of Montpellier Alexander Grothendieck - CNRS UMR5149 and University of Montpellier, Montpellier, 34095, France
| | - Vincent Moureau
- CORIA, CNRS, INSA and University of Rouen, Saint-Etienne-du-Rouvray, 76801, France
| | - Franck Nicoud
- Institute of Montpellier Alexander Grothendieck - CNRS UMR5149 and University of Montpellier, Montpellier, 34095, France
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Biglino G, Capelli C, Bruse J, Bosi GM, Taylor AM, Schievano S. Computational modelling for congenital heart disease: how far are we from clinical translation? Heart 2016; 103:98-103. [PMID: 27798056 PMCID: PMC5284484 DOI: 10.1136/heartjnl-2016-310423] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/17/2022] Open
Abstract
Computational models of congenital heart disease (CHD) have become increasingly sophisticated over the last 20 years. They can provide an insight into complex flow phenomena, allow for testing devices into patient-specific anatomies (pre-CHD or post-CHD repair) and generate predictive data. This has been applied to different CHD scenarios, including patients with single ventricle, tetralogy of Fallot, aortic coarctation and transposition of the great arteries. Patient-specific simulations have been shown to be informative for preprocedural planning in complex cases, allowing for virtual stent deployment. Novel techniques such as statistical shape modelling can further aid in the morphological assessment of CHD, risk stratification of patients and possible identification of new ‘shape biomarkers’. Cardiovascular statistical shape models can provide valuable insights into phenomena such as ventricular growth in tetralogy of Fallot, or morphological aortic arch differences in repaired coarctation. In a constant move towards more realistic simulations, models can also account for multiscale phenomena (eg, thrombus formation) and importantly include measures of uncertainty (ie, CIs around simulation results). While their potential to aid understanding of CHD, surgical/procedural decision-making and personalisation of treatments is undeniable, important elements are still lacking prior to clinical translation of computational models in the field of CHD, that is, large validation studies, cost-effectiveness evaluation and establishing possible improvements in patient outcomes.
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Affiliation(s)
- Giovanni Biglino
- Bristol Heart Institute, School of Clinical Sciences, University of Bristol, Bristol, UK.,Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Claudio Capelli
- Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
| | - Jan Bruse
- Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
| | - Giorgia M Bosi
- Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
| | - Andrew M Taylor
- Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
| | - Silvia Schievano
- Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Institute of Cardiovascular Science, University College London, London, UK
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43
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Taylor JO, Good BC, Paterno AV, Hariharan P, Deutsch S, Malinauskas RA, Manning KB. Analysis of Transitional and Turbulent Flow Through the FDA Benchmark Nozzle Model Using Laser Doppler Velocimetry. Cardiovasc Eng Technol 2016; 7:191-209. [DOI: 10.1007/s13239-016-0270-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/15/2016] [Indexed: 12/27/2022]
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44
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Raben JS, Hariharan P, Robinson R, Malinauskas R, Vlachos PP. Time-Resolved Particle Image Velocimetry Measurements with Wall Shear Stress and Uncertainty Quantification for the FDA Nozzle Model. Cardiovasc Eng Technol 2015; 7:7-22. [DOI: 10.1007/s13239-015-0251-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 11/23/2015] [Indexed: 10/22/2022]
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45
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Berg P, Roloff C, Beuing O, Voss S, Sugiyama SI, Aristokleous N, Anayiotos AS, Ashton N, Revell A, Bressloff NW, Brown AG, Jae Chung B, Cebral JR, Copelli G, Fu W, Qiao A, Geers AJ, Hodis S, Dragomir-Daescu D, Nordahl E, Bora Suzen Y, Owais Khan M, Valen-Sendstad K, Kono K, Menon PG, Albal PG, Mierka O, Münster R, Morales HG, Bonnefous O, Osman J, Goubergrits L, Pallares J, Cito S, Passalacqua A, Piskin S, Pekkan K, Ramalho S, Marques N, Sanchi S, Schumacher KR, Sturgeon J, Švihlová H, Hron J, Usera G, Mendina M, Xiang J, Meng H, Steinman DA, Janiga G. The Computational Fluid Dynamics Rupture Challenge 2013—Phase II: Variability of Hemodynamic Simulations in Two Intracranial Aneurysms. J Biomech Eng 2015; 137:121008. [DOI: 10.1115/1.4031794] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Indexed: 11/08/2022]
Abstract
With the increased availability of computational resources, the past decade has seen a rise in the use of computational fluid dynamics (CFD) for medical applications. There has been an increase in the application of CFD to attempt to predict the rupture of intracranial aneurysms, however, while many hemodynamic parameters can be obtained from these computations, to date, no consistent methodology for the prediction of the rupture has been identified. One particular challenge to CFD is that many factors contribute to its accuracy; the mesh resolution and spatial/temporal discretization can alone contribute to a variation in accuracy. This failure to identify the importance of these factors and identify a methodology for the prediction of ruptures has limited the acceptance of CFD among physicians for rupture prediction. The International CFD Rupture Challenge 2013 seeks to comment on the sensitivity of these various CFD assumptions to predict the rupture by undertaking a comparison of the rupture and blood-flow predictions from a wide range of independent participants utilizing a range of CFD approaches. Twenty-six groups from 15 countries took part in the challenge. Participants were provided with surface models of two intracranial aneurysms and asked to carry out the corresponding hemodynamics simulations, free to choose their own mesh, solver, and temporal discretization. They were requested to submit velocity and pressure predictions along the centerline and on specified planes. The first phase of the challenge, described in a separate paper, was aimed at predicting which of the two aneurysms had previously ruptured and where the rupture site was located. The second phase, described in this paper, aims to assess the variability of the solutions and the sensitivity to the modeling assumptions. Participants were free to choose boundary conditions in the first phase, whereas they were prescribed in the second phase but all other CFD modeling parameters were not prescribed. In order to compare the computational results of one representative group with experimental results, steady-flow measurements using particle image velocimetry (PIV) were carried out in a silicone model of one of the provided aneurysms. Approximately 80% of the participating groups generated similar results. Both velocity and pressure computations were in good agreement with each other for cycle-averaged and peak-systolic predictions. Most apparent “outliers” (results that stand out of the collective) were observed to have underestimated velocity levels compared to the majority of solutions, but nevertheless identified comparable flow structures. In only two cases, the results deviate by over 35% from the mean solution of all the participants. Results of steady CFD simulations of the representative group and PIV experiments were in good agreement. The study demonstrated that while a range of numerical schemes, mesh resolution, and solvers was used, similar flow predictions were observed in the majority of cases. To further validate the computational results, it is suggested that time-dependent measurements should be conducted in the future. However, it is recognized that this study does not include the biological aspects of the aneurysm, which needs to be considered to be able to more precisely identify the specific rupture risk of an intracranial aneurysm.
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Affiliation(s)
- Philipp Berg
- University of Magdeburg, Magdeburg 39106, Germany
| | | | - Oliver Beuing
- University Hospital of Magdeburg, Magdeburg 39120, Germany
| | - Samuel Voss
- University of Magdeburg, Magdeburg 39106, Germany
| | | | | | | | - Neil Ashton
- The University of Manchester, Manchester M60 1QD, UK
| | | | | | | | | | | | | | - Wenyu Fu
- Beijing University of Technology, Beijing 100124, China
| | - Aike Qiao
- Beijing University of Technology, Beijing 100124, China
| | | | - Simona Hodis
- Texas A&M University, Kingsville, TX 78363
- Mayo Clinic, Rochester, MN 55905
| | | | | | | | | | | | - Kenichi Kono
- Wakayama Rosai Hospital, Wakayama 640-8505, Japan
| | - Prahlad G. Menon
- Sun Yat-sen University—Carnegie Mellon University Joint Institute of Engineering, Pittsburgh, PA 15219
| | - Priti G. Albal
- Sun Yat-sen University—Carnegie Mellon University Joint Institute of Engineering, Pittsburgh, PA 15219
| | - Otto Mierka
- University of Dortmund, Dortmund 44227, Germany
| | | | | | | | - Jan Osman
- Charité-Universitätsmedizin Berlin, Berlin 13353, Germany
| | | | | | | | | | | | | | - Susana Ramalho
- blueCAPE Lda—CAE Solutions, Milharado 2665-305, Portugal
| | - Nelson Marques
- blueCAPE Lda—CAE Solutions, Milharado 2665-305, Portugal
| | | | | | | | | | | | - Gabriel Usera
- Universidad de la República, Montevideo 11300, Uruguay
| | | | - Jianping Xiang
- University at Buffalo—State University of New York, Buffalo, NY 14203
| | - Hui Meng
- University at Buffalo—State University of New York, Buffalo, NY 14203
| | | | - Gábor Janiga
- University of Magdeburg, Magdeburg 39106, Germany
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Classification of Unsteady Flow Patterns in a Rotodynamic Blood Pump: Introduction of Non-Dimensional Regime Map. Cardiovasc Eng Technol 2015; 6:230-41. [DOI: 10.1007/s13239-015-0231-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 06/22/2015] [Indexed: 11/25/2022]
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Herbertson LH, Olia SE, Daly A, Noatch CP, Smith WA, Kameneva MV, Malinauskas RA. Multilaboratory study of flow-induced hemolysis using the FDA benchmark nozzle model. Artif Organs 2014; 39:237-48. [PMID: 25180887 DOI: 10.1111/aor.12368] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multilaboratory in vitro blood damage testing was performed on a simple nozzle model to determine how different flow parameters and blood properties affect device-induced hemolysis and to generate data for comparison with computational fluid dynamics-based predictions of blood damage as part of an FDA initiative for assessing medical device safety. Three independent laboratories evaluated hemolysis as a function of nozzle entrance geometry, flow rate, and blood properties. Bovine blood anticoagulated with acid citrate dextrose solution (2-80 h post-draw) was recirculated through nozzle-containing and paired nozzle-free control loops for 2 h. Controlled parameters included hematocrit (36 ± 1.5%), temperature (25 °C), blood volume, flow rate, and pressure. Three nozzle test conditions were evaluated (n = 26-36 trials each): (i) sudden contraction at the entrance with a blood flow rate of 5 L/min, (ii) gradual cone at the entrance with a 6-L/min blood flow rate, and (iii) sudden-contraction inlet at 6 L/min. The blood damage caused only by the nozzle model was calculated by subtracting the hemolysis generated by the paired control loop test. Despite high intralaboratory variability, significant differences among the three test conditions were observed, with the sharp nozzle entrance causing the most hemolysis. Modified index of hemolysis (MIHnozzle ) values were 0.292 ± 0.249, 0.021 ± 0.128, and 1.239 ± 0.667 for conditions i-iii, respectively. Porcine blood generated hemolysis results similar to those obtained with bovine blood. Although the interlaboratory hemolysis results are only applicable for the specific blood parameters and nozzle model used here, these empirical data may help to advance computational fluid dynamics models for predicting blood damage.
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Affiliation(s)
- Luke H Herbertson
- Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD, USA
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Marsden AL, Bazilevs Y, Long CC, Behr M. Recent advances in computational methodology for simulation of mechanical circulatory assist devices. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2014; 6:169-88. [PMID: 24449607 PMCID: PMC3947342 DOI: 10.1002/wsbm.1260] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 11/06/2013] [Accepted: 12/16/2013] [Indexed: 11/07/2022]
Abstract
Ventricular assist devices (VADs) provide mechanical circulatory support to offload the work of one or both ventricles during heart failure. They are used in the clinical setting as destination therapy, as bridge to transplant, or more recently as bridge to recovery to allow for myocardial remodeling. Recent developments in computational simulation allow for detailed assessment of VAD hemodynamics for device design and optimization for both children and adults. Here, we provide a focused review of the recent literature on finite element methods and optimization for VAD simulations. As VAD designs typically fall into two categories, pulsatile and continuous flow devices, we separately address computational challenges of both types of designs, and the interaction with the circulatory system with three representative case studies. In particular, we focus on recent advancements in finite element methodology that have increased the fidelity of VAD simulations. We outline key challenges, which extend to the incorporation of biological response such as thrombosis and hemolysis, as well as shape optimization methods and challenges in computational methodology.
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Affiliation(s)
- Alison L Marsden
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
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49
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Janiga G. Large eddy simulation of the FDA benchmark nozzle for a Reynolds number of 6500. Comput Biol Med 2014; 47:113-9. [PMID: 24561349 DOI: 10.1016/j.compbiomed.2014.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 11/29/2022]
Abstract
This work investigates the flow in a benchmark nozzle model of an idealized medical device proposed by the FDA using computational fluid dynamics (CFD). It was in particular shown that a proper modeling of the transitional flow features is particularly challenging, leading to large discrepancies and inaccurate predictions from the different research groups using Reynolds-averaged Navier-Stokes (RANS) modeling. In spite of the relatively simple, axisymmetric computational geometry, the resulting turbulent flow is fairly complex and non-axisymmetric, in particular due to the sudden expansion. The resulting flow cannot be well predicted with simple modeling approaches. Due to the varying diameters and flow velocities encountered in the nozzle, different typical flow regions and regimes can be distinguished, from laminar to transitional and to weakly turbulent. The purpose of the present work is to re-examine the FDA-CFD benchmark nozzle model at a Reynolds number of 6500 using large eddy simulation (LES). The LES results are compared with published experimental data obtained by Particle Image Velocimetry (PIV) and an excellent agreement can be observed considering the temporally averaged flow velocities. Different flow regimes are characterized by computing the temporal energy spectra at different locations along the main axis.
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Affiliation(s)
- Gábor Janiga
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke", Germany
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Passerini T, Quaini A, Villa U, Veneziani A, Canic S. Validation of an open source framework for the simulation of blood flow in rigid and deformable vessels. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2013; 29:1192-213. [PMID: 23798339 PMCID: PMC3844109 DOI: 10.1002/cnm.2568] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/25/2013] [Accepted: 05/16/2013] [Indexed: 05/17/2023]
Abstract
We discuss in this paper the validation of an open source framework for the solution of problems arising in hemodynamics. The proposed framework is assessed through experimental data for fluid flow in an idealized medical device with rigid boundaries and a numerical benchmark for flow in compliant vessels. The core of the framework is an open source parallel finite element library that features several algorithms to solve both fluid and fluid-structure interaction problems. The numerical results for the flow in the idealized medical device (consisting of a conical convergent, a narrow throat, and a sudden expansion) are in good quantitative agreement with the measured axial components of the velocity and pressures for three different flow rates corresponding to laminar, transitional, and turbulent regimes. We emphasize the crucial role played by the accuracy in performing numerical integration, mesh, and time step to match the measurements. The numerical fluid-structure interaction benchmark deals with the propagation of a pressure wave in a fluid-filled elastic tube. The computed pressure wave speed and frequency of oscillations, and the axial velocity of the fluid on the tube axis are close to the values predicted by the analytical solution associated with the benchmark. A detailed account of the methods used for both benchmarks is provided.
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Affiliation(s)
- T. Passerini
- Department of Mathematics and Computer Science, Emory University, 400 Dowman Drive, Atlanta GA 30322, USA
| | - A. Quaini
- Department of Mathematics, University of Houston, 4800 Calhoun Rd., Houston TX 77204, USA
- Correspondence to: A. Quaini, Department of Mathematics, University of Houston, Houston TX 77204, USA.
| | - U. Villa
- Department of Mathematics and Computer Science, Emory University, 400 Dowman Drive, Atlanta GA 30322, USA
| | - A. Veneziani
- Department of Mathematics and Computer Science, Emory University, 400 Dowman Drive, Atlanta GA 30322, USA
| | - S. Canic
- Department of Mathematics, University of Houston, 4800 Calhoun Rd., Houston TX 77204, USA
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