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Xu KW, Gao Q, Wan M, Zhang K. Mock circulatory loop applications for testing cardiovascular assist devices and in vitro studies. Front Physiol 2023; 14:1175919. [PMID: 37123281 PMCID: PMC10133581 DOI: 10.3389/fphys.2023.1175919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/03/2023] [Indexed: 05/02/2023] Open
Abstract
The mock circulatory loop (MCL) is an in vitro experimental system that can provide continuous pulsatile flows and simulate different physiological or pathological parameters of the human circulation system. It is of great significance for testing cardiovascular assist device (CAD), which is a type of clinical instrument used to treat cardiovascular disease and alleviate the dilemma of insufficient donor hearts. The MCL installed with different types of CADs can simulate specific conditions of clinical surgery for evaluating the effectiveness and reliability of those CADs under the repeated performance tests and reliability tests. Also, patient-specific cardiovascular models can be employed in the circulation of MCL for targeted pathological study associated with hemodynamics. Therefore, The MCL system has various combinations of different functional units according to its richful applications, which are comprehensively reviewed in the current work. Four types of CADs including prosthetic heart valve (PHV), ventricular assist device (VAD), total artificial heart (TAH) and intra-aortic balloon pump (IABP) applied in MCL experiments are documented and compared in detail. Moreover, MCLs with more complicated structures for achieving advanced functions are further introduced, such as MCL for the pediatric application, MCL with anatomical phantoms and MCL synchronizing multiple circulation systems. By reviewing the constructions and functions of available MCLs, the features of MCLs for different applications are summarized, and directions of developing the MCLs are suggested.
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Affiliation(s)
- Ke-Wei Xu
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China
| | - Qi Gao
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China
- *Correspondence: Qi Gao,
| | - Min Wan
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, Jinan, China
| | - Ke Zhang
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, Jinan, China
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2
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Cappon F, Wu T, Papaioannou T, Du X, Hsu PL, Khir AW. Mock circulatory loops used for testing cardiac assist devices: A review of computational and experimental models. Int J Artif Organs 2021; 44:793-806. [PMID: 34581613 DOI: 10.1177/03913988211045405] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Heart failure is a major health risk, and with limited availability of donor organs, there is an increasing need for developing cardiac assist devices (CADs). Mock circulatory loops (MCL) are an important in-vitro test platform for CAD's performance assessment and optimisation. The MCL is a lumped parameter model constructed out of hydraulic and mechanical components aiming to simulate the native cardiovascular system (CVS) as closely as possible. Further development merged MCLs and numerical circulatory models to improve flexibility and accuracy of the system; commonly known as hybrid MCLs. A total of 128 MCLs were identified in a literature research until 25 September 2020. It was found that the complexity of the MCLs rose over the years, recent MCLs are not only capable of mimicking the healthy and pathological conditions, but also implemented cerebral, renal and coronary circulations and autoregulatory responses. Moreover, the development of anatomical models made flow visualisation studies possible. Mechanical MCLs showed excellent controllability and repeatability, however, often the CVS was overly simplified or lacked autoregulatory responses. In numerical MCLs the CVS is represented with a higher order of lumped parameters compared to mechanical test rigs, however, complex physiological aspects are often simplified. In hybrid MCLs complex physiological aspects are implemented in the hydraulic part of the system, whilst the numerical model represents parts of the CVS that are too difficult to represent by mechanical components per se. This review aims to describe the advances, limitations and future directions of the three types of MCLs.
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Affiliation(s)
- Femke Cappon
- Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge, UK
| | - Tingting Wu
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Theodore Papaioannou
- Biomedical Engineering Unit, First Department of Cardiology, Medical School, National and Kapodistrian University of Athens, Zografou, Greece
| | - Xinli Du
- Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge, UK
| | - Po-Lin Hsu
- Department of Mechanical and Electrical Engineering, Soochow University, Suzhou, China
| | - Ashraf W Khir
- Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge, UK
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3
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Gregory SD, Pauls JP, Wu EL, Stephens A, Steinseifer U, Tansley G, Fraser JF. An advanced mock circulation loop for in vitro cardiovascular device evaluation. Artif Organs 2020; 44:E238-E250. [PMID: 31951020 DOI: 10.1111/aor.13636] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/11/2019] [Accepted: 01/07/2020] [Indexed: 11/28/2022]
Abstract
Controlled and repeatable in vitro evaluation of cardiovascular devices using a mock circulation loop (MCL) is essential prior to in vivo or clinical trials. MCLs often consist of only a systemic circulation with no autoregulatory responses and limited validation. This study aimed to develop, and validate against human data, an advanced MCL with systemic, pulmonary, cerebral, and coronary circulations with autoregulatory responses. The biventricular MCL was constructed with pneumatically controlled hydraulic circulations with Starling responsive ventricles and autoregulatory cerebral and coronary circulations. Hemodynamic repeatability was assessed and complemented by validation using impedance cardiography data from 50 healthy humans. The MCL successfully simulated patient scenarios including rest, exercise, and left heart failure with and without cardiovascular device support. End-systolic pressure-volume relationships for respective healthy and heart failure conditions had slopes of 1.27 and 0.54 mm Hg mL-1 (left ventricle), and 0.18 and 0.10 mm Hg mL-1 (right ventricle), aligning with the literature. Coronary and cerebral autoregulation showed a strong correlation (R2 : .99) between theoretical and experimentally derived circuit flow. MCL repeatability was demonstrated with correlation coefficients being statistically significant (P < .05) for all simulated conditions while MCL hemodynamics aligned well with human data. This advanced MCL is a valuable tool for inexpensive and controlled evaluation of cardiovascular devices.
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Affiliation(s)
- Shaun D Gregory
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.,School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia.,School of Medicine, University of Queensland, Brisbane, QLD, Australia
| | - Jo P Pauls
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.,School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia.,School of Medicine, University of Queensland, Brisbane, QLD, Australia
| | - Eric L Wu
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.,School of Medicine, University of Queensland, Brisbane, QLD, Australia
| | - Andrew Stephens
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Ulrich Steinseifer
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Geoff Tansley
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.,School of Engineering and Built Environment, Griffith University, Southport, QLD, Australia
| | - John F Fraser
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia.,School of Medicine, University of Queensland, Brisbane, QLD, Australia
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Korakianitis T, Rezaienia MA, Paul G, Avital E, Rothman M, Mozafari S. Optimization of Axial Pump Characteristic Dimensions and Induced Hemolysis for Mechanical Circulatory Support Devices. ASAIO J 2019; 64:727-734. [PMID: 29117039 PMCID: PMC5837008 DOI: 10.1097/mat.0000000000000719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The application of axial pumps as ventricular assist devices (VADs) requires significant modifications to the size and characteristics of industrial pumps due to the difference in flow fields of industrial and medical pumps. Industrial pumps operate in the region of Reynolds number Re = 10, whereas axial blood pumps operate in Re < 10. The common pump design technique is to rely on the performance of previously designed pumps using the concept of fluid dynamic similarity. Such data are available for industrial pumps as specific speed-specific diameter (ns-ds) graphs. The difference between the flow fields of industrial and medical pumps makes the industrial ns-ds graphs unsuitable for medical pumps and consequently several clinically available axial blood pumps operate with low efficiencies. In this article, numerical and experimental techniques were used to design 62 axial pump impellers with different design characteristics suitable for VADs and mechanical circulatory support devices (MCSDs). The impellers were manufactured and experimentally tested in various operating conditions of flow, pressure, and rotational speed. The hemocompatibility of the impellers was numerically investigated by modeling shear stress and hemolysis. The highest efficiency of each pump impeller was plotted on an ns-ds diagram. The nondimensional results presented in this article enable preliminary design of efficient and hemocompatible axial flow pumps for VADs and MCSDs.
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Affiliation(s)
- Theodosios Korakianitis
- From the Parks College of Engineering, Aviation and Technology, Saint Louis University, St. Louis, Missouri
| | - Mohammad Amin Rezaienia
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Gordon Paul
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Eldad Avital
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Martin Rothman
- Department of Cardiology, Barts and the London NHS Trust, London Chest Hospital, London E2 9JX, United Kingdom
| | - Sahand Mozafari
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, United Kingdom
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Bozkurt S. Effect of Cerebral Flow Autoregulation Function on Cerebral Flow Rate Under Continuous Flow Left Ventricular Assist Device Support. Artif Organs 2018; 42:800-813. [DOI: 10.1111/aor.13148] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/13/2018] [Accepted: 02/20/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Selim Bozkurt
- University College London - Institute of Cardiovascular Science; London United Kingdom of Great Britain and Northern Ireland
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Wu W. A pressure-driven gas-diffusion/permeation micropump for self-activated sample transport in an extreme micro-environment. Analyst 2018; 143:4819-4835. [DOI: 10.1039/c8an01120f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pressure-driven gas-diffusion/permeation micropump is highlighted for stable microdroplet/liquid delivery under extreme conditions,e.g.high temperature, and a three-dimensional, long-distance and complex-topology microchannel.
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Affiliation(s)
- Wenming Wu
- State Key Laboratory of Applied Optics
- Changchun Institute of Optics
- Fine Mechanics and Physics
- Chinese Academy of Sciences
- Changchun
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Computational Parametric Study of the Axial and Radial Clearances in a Centrifugal Rotary Blood Pump. ASAIO J 2017; 64:643-650. [PMID: 29076943 DOI: 10.1097/mat.0000000000000700] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In centrifugal rotary blood pumps (RBP), clearances are a critical parameter in determining blood trauma. This study investigates the effect of axial clearance (Cax) and radial clearance (Crad) on the hydrodynamic and hemolytic performance of a centrifugal RBP. A centrifugal pump was parameterized so that it could be defined by geometric variables Cax and Crad. Optimal Latin hypercube sampling was used to determine design points based on Cax, Crad, and rotor speed (ω). For each design point, a computational simulation was conducted to determine efficiency (η) and normalized index of hemolysis (NIH). Next, a response surface (RS) was created to estimate these performance parameters based on the design variables. The results show that for a given Cax, when Crad is decreased, η increases until Crad = 0.15 mm, beyond which η deceases. For a given Crad, Cax has a unimodal relationship with η. The NIH has a unimodal relationship with both Cax and Crad. The mechanisms behind these relationships were investigated by various analytical methods. It was found that vortices in the secondary flow paths were a critical factor in determining efficiency and hemolysis. The optimal clearance values discerned in this study are only valid for the specific impeller geometry and operating conditions analyzed.
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Okamoto E, Yano T, Miura H, Shiraishi Y, Yambe T, Mitamura Y. Measurement of hemodynamic changes with the axial flow blood pump installed in descending aorta. J Artif Organs 2017; 20:390-393. [PMID: 28887718 DOI: 10.1007/s10047-017-0985-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 08/01/2017] [Indexed: 11/26/2022]
Abstract
We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43.8 kg, female). When the pump was on, the aortic pressure and aortic flow downstream of the pump increased with preservation of pulsatilities. The pressure drop upstream of the pump caused reduction of afterload pressure, and it may lead to reduction of left ventricular wall stress. However, cerebral blood flow and coronary blood flow were decreased when the pump was on. The axial flow blood pump enables more effective blood perfusion into systemic circulation, but it has the potential risk of blood perfusion disturbance into cerebral circulation and coronary circulation. The results indicate that the position before the coronary ostia might be suitable for implantation of the axial flow blood pump in series with the natural heart to avoid blood perfusion disturbances.
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Affiliation(s)
- Eiji Okamoto
- Graduate School of Science and Engineering, Tokai University, Minami-sawa 5-1-1-1, Minami-ku, Sapporo, 005-8601, Japan.
| | - Tetsuya Yano
- Graduate School of Science and Engineering, Hirosaki University, Hirosaki, Japan
| | - Hidekazu Miura
- Faculty of Medical Engineering, Suzuka University of Medical Science, Suzuka, Japan
| | - Yasuyuki Shiraishi
- Institute of Development Aging and Cancer, Tohoku University, Sendai, Japan
| | - Tomoyuki Yambe
- Institute of Development Aging and Cancer, Tohoku University, Sendai, Japan
| | - Yoshinori Mitamura
- Graduate School of Science and Engineering, Tokai University, Minami-sawa 5-1-1-1, Minami-ku, Sapporo, 005-8601, Japan
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Paul G, Rezaienia A, Avital E, Korakianitis T. Machinability and Optimization of Shrouded Centrifugal Impellers for Implantable Blood Pumps. J Med Device 2017. [DOI: 10.1115/1.4036287] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This paper describes the use of analytical methods to determine machinable centrifugal impeller geometries and the use of computational fluid dynamics (CFD) for predicting the impeller performance. An analytical scheme is described to determine the machinable geometries for a shrouded centrifugal impeller with blades composed of equiangular spirals. The scheme is used to determine the maximum machinable blade angles for impellers with three to nine blades in a case study. Computational fluid dynamics is then used to analyze all the machinable geometries and determine the optimal blade number and angle based on measures of efficiency and rotor speed. The effect of tip width on rotor speed and efficiency is also examined. It is found that, for our case study, a six- or seven-bladed impeller with a low blade angle provides maximum efficiency and minimum rotor speed.
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Affiliation(s)
- Gordon Paul
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Amin Rezaienia
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Eldad Avital
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Theodosios Korakianitis
- Professor Parks College of Engineering, Aviation and Technology, Saint Louis University, St. Louis, MO 63103 e-mail:
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Rezaienia MA, Paul G, Avital EJ, Mozafari S, Rothman M, Korakianitis T. In-vitro investigation of the hemodynamic responses of the cerebral, coronary and renal circulations with a rotary blood pump installed in the descending aorta. Med Eng Phys 2016; 40:2-10. [PMID: 28040435 DOI: 10.1016/j.medengphy.2016.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/02/2016] [Accepted: 11/13/2016] [Indexed: 02/08/2023]
Abstract
This study investigates the hemodynamic responses of the cardiovascular system when a rotary blood pump is operating in the descending aorta, with a focus on the cerebral, coronary and renal autoregulation, using our in-house cardiovascular emulator. Several improvements have been made from our previous studies. A novel coronary system was developed to replicate the native coronary perfusion. Three pinch valves actuated by stepper motors were used to simulate the regional autoregulation systems of the native cerebral, coronary and renal circulations. A rotary pump was installed in the descending aorta, in series with the heart, and the hemodynamic responses of the cardiovascular system were investigated with a focus on cerebral, coronary and renal circulation over a wide range of pump rotor speeds. Experiments were performed twice, once with the autoregulation systems active and once with the autoregulation systems inactive, to reflect that there will be some impairment of autoregulatory systems in a patient with heart failure. It was shown that by increasing the rotor speed to 3000 rpm, the cardiac output was improved from 2.9 to 4.1 L/min as a result of an afterload reduction induced by the pressure drop upstream of the pump. The magnitudes of changes in perfusion in the cerebral, coronary and renal circulations were recorded with regional autoregulation systems active and inactive.
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Affiliation(s)
- M A Rezaienia
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - G Paul
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - E J Avital
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - S Mozafari
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - M Rothman
- Department of Cardiology, London Chest Hospital, Barts and the London NHS Trust, London E2 9JX, UK
| | - T Korakianitis
- Parks College of Engineering, Aviation and Technology, Saint Louis University, St. Louis, Missouri 63103, USA.
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