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Huo M, Giridharan GA, Sethu P, Qu P, Qin K, Wang Y. Numerical simulation analysis of multi-scale computational fluid dynamics on hemodynamic parameters modulated by pulsatile working modes for the centrifugal and axial left ventricular assist devices. Comput Biol Med 2024; 169:107788. [PMID: 38091724 DOI: 10.1016/j.compbiomed.2023.107788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 11/08/2023] [Accepted: 11/28/2023] [Indexed: 02/08/2024]
Abstract
Continuous flow (CF) left ventricular assist devices (LVAD) operate at a constant speed mode, which could result in increased risk of adverse events due to reduced vascular pulsatility. Consequently, pump speed modulation algorithms have been proposed to augment vascular pulsatility. However, the quantitative local hemodynamic effects on the aorta when the pump is operating with speed modulation using different types of CF-LVADs are still under investigation. The computational fluid dynamics (CFD) study was conducted to quantitatively elucidate the hemodynamic effects on a clinical patient-specific aortic model under different speed patterns of CF-LVADs. Pressure distribution, wall shear stress (WSS), time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and velocity were calculated to compare their differences at constant and pulsatile speeds under centrifugal and axial LVAD support. Results showed that pulse pressure on the aorta was significantly larger under pulsatile speed mode than that under constant speed mode for both CF-LVADs, indicating enhanced aorta pulsatility, as well as the higher peak blood flow velocity on some representative slices of aorta. Pulsatile speed modulation enhanced peak WSS compared to constant speed; high TAWSS region appeared near the branch of left common carotid artery and distal aorta regardless of speed modes and CF-LVADs but these regions also had low OSI; RRT was almost the same for all the cases. This study may provide a basis for the scientific and reasonable selection of the pulsatile speed patterns of CF-LVADs for treating heart failure patients.
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Affiliation(s)
- Mingming Huo
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, China
| | | | - Palaniappan Sethu
- Division of Cardiovascular Disease, Department of Medicine, School of Medicine and Department of Biomedical Engineering, School of Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Peng Qu
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Dalian, China
| | - Kairong Qin
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Dalian, China
| | - Yu Wang
- School of Biomedical Engineering, Faculty of Medicine, Dalian University of Technology, Dalian, China.
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Netuka I, Pya Y, Poitier B, Ivak P, Konarik M, Perlès JC, Blažejová Z, Riha H, Bekbossynova M, Medressova A, Bousquet F, Latrémouille C, Jansen P. First Clinical Experience With the Pressure Sensor-Based Autoregulation of Blood Flow in an Artificial Heart. ASAIO J 2021; 67:1100-1108. [PMID: 34138778 PMCID: PMC8478302 DOI: 10.1097/mat.0000000000001485] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The CARMAT-Total Artificial Heart (C-TAH) is designed to provide heart replacement therapy for patients with end-stage biventricular failure. This report details the reliability and efficacy of the autoregulation device control mechanism (auto-mode), designed to mimic normal physiologic responses to changing patient needs. Hemodynamic data from a continuous cohort of 10 patients implanted with the device, recorded over 1,842 support days in auto-mode, were analyzed with respect to daily changing physiologic needs. The C-TAH uses embedded pressure sensors to regulate the pump output. Right and left ventricular outputs are automatically balanced. The operator sets target values and the inbuilt algorithm adjusts the stroke volume and beat rate, and hence cardiac output, automatically. Auto-mode is set perioperatively after initial postcardiopulmonary bypass hemodynamic stabilization. All patients showed a range of average inflow pressures of between 5 and 20 mm Hg during their daily activities, resulting in cardiac output responses of between 4.3 and 7.3 L/min. Operator adjustments were cumulatively only required on 20 occasions. This report demonstrates that the C-TAH auto-mode effectively produces appropriate physiologic responses reflective of changing patients' daily needs and represents one of the unique characteristics of this device in providing almost physiologic heart replacement therapy.
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Affiliation(s)
- Ivan Netuka
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Yuriy Pya
- National Research Cardiac Surgery Center (NRCSC), Nur-Sultan (Astana), Kazakhstan
| | | | - Peter Ivak
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Miroslav Konarik
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Jean-Christophe Perlès
- Carmat SA, Vélizy, France; and ¶Department of Anesthesiology and Intensive Care Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Zuzana Blažejová
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Hynek Riha
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Makhabbat Bekbossynova
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Assel Medressova
- From the Department of Cardiovascular Surgery, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Fabien Bousquet
- Carmat SA, Vélizy, France; and ¶Department of Anesthesiology and Intensive Care Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | | | - Piet Jansen
- Carmat SA, Vélizy, France; and ¶Department of Anesthesiology and Intensive Care Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Liu H, Liu S, Ma X. Varying speed modulation of continuous-flow left ventricular assist device based on cardiovascular coupling numerical model. Comput Methods Biomech Biomed Engin 2020; 24:956-972. [PMID: 33347766 DOI: 10.1080/10255842.2020.1861601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Continuous-flow left ventricular assist devices (CFLVADs) routinely operate at a constant speed for the support of a failing heart, which decreases the pulsatility in the arteries. Some late complications could be related to a long-term lack of pulsatility. Modulating the CFLVAD speed is a solution to enhance the pulsatility. The purpose of this study is to modulate multiple varying speed patterns and investigate their effects on the ventricle and vascular system. A cardiovascular coupling numerical model is developed to provide a simulation platform for testing the varying speed patterns. The varying speed patterns are modulated by combining the shape, amplitude, frequency, phase shift, and pulsatile duty cycle of the speed profile. The influence of varying speed support is examined by analyzing the indexes of pulsatility, indexes of ventricular unloading, and hemodynamic variables. The results show that the synchronous counterpulsation pattern can effectively reduce the ventricular unloading indexes, whereas the low-frequency asynchronous pattern can effectively increase the vascular pulsatility indexes. Also, the hemodynamics with synchronous varying speed support is more physiological than that with asynchronous varying speed support. This study provides valuable insight for further optimization of varying speed modulation by weighing vascular pulsatility, ventricular unloading, and hemodynamics.
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Affiliation(s)
- Hongtao Liu
- School of Electrical Engineering, Shandong University, Jinan, PR China
| | - Shuqin Liu
- School of Electrical Engineering, Shandong University, Jinan, PR China
| | - Xiaoxu Ma
- School of Electrical Engineering, Shandong University, Jinan, PR China
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Shi Y, Yang H. Mock circulatory test rigs for the in vitro testing of artificial cardiovascular organs. J Med Eng Technol 2019; 43:223-234. [PMID: 31464556 DOI: 10.1080/03091902.2019.1653390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In vitro study plays an important role in the experimental study of cardiovascular dynamics. An essential hardware facility that mimics the blood flow changes and provides the required test conditions, a mock circulatory test rig (MCTR), is imperative for the execution of in vitro study. This paper examines the current MCTRs in use for the testing of artificial cardiovascular organs. Various aspects of the MCTRs are surveyed, including the necessity of in vitro study, the building of MCTRs, relevant standards, general system structure (e.g., the motion and driving, fluid, measurement subsystems), classification, motion driving mechanism of MCTRs, and the considerations for the modelling of the physiological impedance of MCTRs. Examples of the steady and pulsatile flow types of the MCTRs are introduced. Recent developments in MCTRs are inspected and possible future design improvements suggested. This study will help researchers in the design, construction, analysis, and selection of MCTRs for cardiovascular research.
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Affiliation(s)
- Yubing Shi
- College of Medical Technology, Shaanxi University of Chinese Medicine , Xianyang , PR China
| | - Hongyi Yang
- College of Medical Technology, Shaanxi University of Chinese Medicine , Xianyang , PR China
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Right ventricular failure management. Curr Opin Cardiol 2018; 34:213-217. [PMID: 30575646 DOI: 10.1097/hco.0000000000000595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Review recent advances in the diagnosis and management of right ventricular (RV) failure. RECENT FINDINGS Temporary and durable device-based management of RV failure has emerging applications. SUMMARY Research advances and clinical management in RV failure have been limited by a lack of consensus on a universal definition. Echocardiographic and cardiac MRI-based predictors of RV failure are imperfect. Combinations of hemodynamic and imaging variables may have better predictive value. Loading conditions and ventriculo-arterial coupling play important roles in RV function. The current treatment approach to RV failure includes a combination of inotropy and vasodilatation but lacks conclusive evidence. Emerging biochemical and molecular targets hold promise but have yet to be proven in human studies.
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Shi Y, Korakianitis T, Li Z, Shi Y. Structure and motion design of a mock circulatory test rig. J Med Eng Technol 2018; 42:443-452. [PMID: 30499728 DOI: 10.1080/03091902.2018.1543467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mock circulatory test rig (MCTR) is the essential and indispensable facility in the cardiovascular in vitro studies. The system configuration and the motion profile of the MCTR design directly influence the validity, precision, and accuracy of the experimental data collected. Previous studies gave the schematic but never describe the structure and motion design details of the MCTRs used, which makes comparison of the experimental data reported by different research groups plausible but not fully convincing. This article presents the detailed structure and motion design of a sophisticated MCTR system, and examines the important issues such as the determination of the ventricular motion waveform, modelling of the physiological impedance, etc., in the MCTR designing. The study demonstrates the overall design procedures from the system conception, cardiac model devising, motion planning, to the motor and accessories selection. This can be used as a reference to aid researchers in the design and construction of their own in-house MCTRs for cardiovascular studies.
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Affiliation(s)
- Yuhui Shi
- a Northwest Institute of Mechanical and Electrical Engineering , Xianyang , Shaanxi Province , China
| | - Theodosios Korakianitis
- b Parks College of Engineering, Aviation and Technology , Saint Louis University , Saint Louis , MO , USA
| | - Zhongjian Li
- c College of Automation , Northwestern Polytechnical University , Xi'an , China
| | - Yubing Shi
- d Faculty of Arts, Science and Technology , University of Northampton , Northampton , UK
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