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Cai L, Zhong Q, Xu J, Huang Y, Gao H. A lumped parameter model for evaluating coronary artery blood supply capacity. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2024; 21:5838-5862. [PMID: 38872561 DOI: 10.3934/mbe.2024258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
The coronary artery constitutes a vital vascular system that sustains cardiac function, with its primary role being the conveyance of indispensable nutrients to the myocardial tissue. When coronary artery disease occurs, it will affect the blood supply of the heart and induce myocardial ischemia. Therefore, it is of great significance to numerically simulate the coronary artery and evaluate its blood supply capacity. In this article, the coronary artery lumped parameter model was derived based on the relationship between circuit system parameters and cardiovascular system parameters, and the blood supply capacity of the coronary artery in healthy and stenosis states was studied. The aortic root pressure calculated by the aortic valve fluid-structure interaction (AV FSI) simulator was employed as the inlet boundary condition. To emulate the physiological phenomenon of sudden pressure drops resulting from an abrupt reduction in blood vessel radius, a head loss model was connected at the coronary artery's entrance. For each coronary artery outlet, the symmetric structured tree model was appended to simulate the terminal impedance of the missing downstream coronary arteries. The particle swarm optimization (PSO) algorithm was used to optimize the blood flow viscous resistance, blood flow inertia, and vascular compliance of the coronary artery model. In the stenosis states, the relative flow and fractional flow reserve (FFR) calculated by numerical simulation corresponded to the published literature data. It was anticipated that the proposed model can be readily adapted for clinical application, serving as a valuable reference for diagnosing and treating patients.
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Affiliation(s)
- Li Cai
- School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
- NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
- Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
| | - Qian Zhong
- School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
- NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
- Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
| | - Juan Xu
- School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
- NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
- Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
| | - Yuan Huang
- Department of Mathematics, University of Cambridge, Cambridge CB2 1TN, UK
| | - Hao Gao
- School of Mathematics and Statistics, University of Glasgow, Glasgow G12 8QQ, UK
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2
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Li B, Li G, Liu J, Sun H, Wen C, Yang Y, Qiao A, Liu J, Liu Y. Deep-learning-based real-time individualization for reduce-order haemodynamic model. Comput Biol Med 2024; 174:108476. [PMID: 38636328 DOI: 10.1016/j.compbiomed.2024.108476] [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: 08/17/2023] [Revised: 03/18/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024]
Abstract
The reduced-order lumped parameter model (LPM) has great computational efficiency in real-time numerical simulations of haemodynamics but is limited by the accuracy of patient-specific computation. This study proposed a method to achieve the individual LPM modeling with high accuracy to improve the practical clinical applicability of LPM. Clinical data was collected from two medical centres comprising haemodynamic indicators from 323 individuals, including brachial artery pressure waveforms, cardiac output data, and internal carotid artery flow waveforms. The data were expanded to 5000 synthesised cases that all fell within the physiological range of each indicator. LPM of the human blood circulation system was established. A double-path neural network (DPNN) was designed to input the waveforms of each haemodynamic indicator and their key features and then output the individual parameters of the LPM, which was labelled using a conventional optimization algorithm. Clinically collected data from the other 100 cases were used as the test set to verify the accuracy of the individual LPM parameters predicted by DPNN. The results show that DPNN provided good convergence in the training process. In the test set, compared with clinical measurements, the mean differences between each haemodynamic indicator and the estimate calculated by the individual LPM based on the DPNN were about 10 %. Furthermore, DPNN prediction only takes 4 s for 100 cases. The DPNN proposed in this study permits real-time and accurate individualization of LPM's. When facing medical issues involving haemodynamics, it lays the foundation for patient-specific numerical simulation, which may be beneficial for potential clinical application.
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Affiliation(s)
- Bao Li
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Guangfei Li
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China.
| | - Jincheng Liu
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Hao Sun
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Chuanqi Wen
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Yang Yang
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Aike Qiao
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
| | - Jian Liu
- Department of Cardiology, Peking University People's Hospital, Beijing, China
| | - Youjun Liu
- Department of Biomedical Engineering, College of Chemistry and Life Science, Beijing University of Technology, Beijing, China
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3
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Fan L, Wang H, Kassab GS, Lee LC. Review of cardiac-coronary interaction and insights from mathematical modeling. WIREs Mech Dis 2024; 16:e1642. [PMID: 38316634 PMCID: PMC11081852 DOI: 10.1002/wsbm.1642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/10/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024]
Abstract
Cardiac-coronary interaction is fundamental to the function of the heart. As one of the highest metabolic organs in the body, the cardiac oxygen demand is met by blood perfusion through the coronary vasculature. The coronary vasculature is largely embedded within the myocardial tissue which is continually contracting and hence squeezing the blood vessels. The myocardium-coronary vessel interaction is two-ways and complex. Here, we review the different types of cardiac-coronary interactions with a focus on insights gained from mathematical models. Specifically, we will consider the following: (1) myocardial-vessel mechanical interaction; (2) metabolic-flow interaction and regulation; (3) perfusion-contraction matching, and (4) chronic interactions between the myocardium and coronary vasculature. We also provide a discussion of the relevant experimental and clinical studies of different types of cardiac-coronary interactions. Finally, we highlight knowledge gaps, key challenges, and limitations of existing mathematical models along with future research directions to understand the unique myocardium-coronary coupling in the heart. This article is categorized under: Cardiovascular Diseases > Computational Models Cardiovascular Diseases > Biomedical Engineering Cardiovascular Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Lei Fan
- Joint Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Haifeng Wang
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, California, USA
| | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
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4
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Wang H, Fan L, Choy JS, Kassab GS, Lee LC. Simulation of coronary capillary transit time based on full vascular model of the heart. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 243:107908. [PMID: 37931581 PMCID: PMC10872892 DOI: 10.1016/j.cmpb.2023.107908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/08/2023]
Abstract
Capillary transit time (CTT) is a fundamental determinant of gas exchange between blood and tissues in the heart and other organs. Despite advances in experimental techniques, it remains difficult to measure coronary CTT in vivo. Here, we developed a novel computational framework that couples coronary microcirculation with cardiac mechanics in a closed-loop system that enables prediction of hemodynamics in the entire coronary network, including arteries, veins, and capillaries. We also developed a novel "particle-tracking" approach for computing CTT where "virtual tracers" are individually tracked as they traverse the capillary network. Model predictions compare well with blood pressure and flow rate distributions in the arterial network reported in previous studies. Model predictions of transit times in the capillaries (1.21 ± 1.5 s) and entire coronary network (11.8 ± 1.8 s) also agree with measurements. We show that, with increasing coronary artery stenosis (as quantified by fractional flow reserve, FFR), intravascular pressure and flow rate downstream are reduced but remain non-stationary even at 100 % stenosis because some flow (∼3 %) is redistributed from the non-occluded to the occluded territories. Importantly, the model predicts that occlusion of a large artery results in higher CTT. For moderate stenosis (FFR > 0.6), the increase in CTT (from 1.21 s without stenosis to 2.23 s at FFR=0.6) is caused by a decrease in capillary flow rate. In severe stenosis (FFR = 0.1), the increase in CTT to 14.2 s is due to both a decrease in flow rate and an increase in path length taken by "virtual tracers" in the capillary network.
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Affiliation(s)
- Haifeng Wang
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA.
| | - Lei Fan
- The Joint Department of Biomedical Engineering, Marquette University and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jenny S Choy
- California Medical Innovations Institute, San Diego, California, USA
| | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, California, USA
| | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
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5
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Pearce NF, Kim EJ. A new synergistic model for simulating exercise incorporating control mechanisms at cellular and organ scales. Comput Biol Med 2023; 163:107141. [PMID: 37327758 DOI: 10.1016/j.compbiomed.2023.107141] [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: 04/04/2023] [Revised: 05/24/2023] [Accepted: 06/04/2023] [Indexed: 06/18/2023]
Abstract
The physiological response of the cardio-vascular system (CVS) to physical activity is of great importance to those working in sporting research and has profound consequences for the health and well-being of people. Coronary vasodilation and the physiological mechanisms involved in exercise have frequently been the focus of numerical models for simulating exercise. This is partly achieved using the time-varying-elastance (TVE) theory, which prescribes the pressure-volume relationship of the ventricle as a periodic function of time, tuned using empirical data. The empirical foundations of the TVE method however, and its suitability for CVS modelling are frequently questioned. To overcome this challenge, we adopt a different synergistic approach in which a model for the microscale heart muscle (myofibers) activity is embedded within a macro organ-scale CVS model. We developed such a synergistic model by including the coronary flow and various control mechanisms at the circulation level through feedback and feedforward means, and at the microscale (contractile) through the regulation of ATP availability and myofiber force depending on exercise intensity or heart rate. The coronary flow produced by the model displays the well-known 2-phase character of the flow, which is preserved under exercise. The model is tested by simulating reactive hyperemia, which is a transient occlusion of the coronary flow, successfully reproducing the additional coronary flow following the block removal. On-transient exercise results reveal a rise in both cardiac output and mean ventricle pressure as expected. The stroke volume increases initially, but then declines during the latter period of HR rise, corresponding with one of the main physiological responses to exercise. The pressure-volume loop expands during exercise, as systolic pressure rises. The Myocardial oxygen demand increases during exercise and the coronary blood supply increases in response, causing an excess of oxygen supply to the heart. Off-transient exercise recovery is largely a reverse of this response, although the behaviour is slightly more varied, with sudden spikes in coronary resistance. Different levels of fitness and exercise intensity are tested and reveal that the stroke volume rises until a level of myocardial oxygen demand is reached at which point it declines. This level of demand is independent of fitness or exercise intensity. An advantage of our model is demonstrated in the correspondence between the micro and organ scale mechanics so that cellular pathologies can be traced from exercise performance with relatively little computational or experimental expense.
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Affiliation(s)
- Nicholas F Pearce
- Fluids and Complex Systems Center, Faculty of Engineering, Environment and Computing, Coventry University, Coventry, CV1 5FB, UK.
| | - Eun-Jin Kim
- Fluids and Complex Systems Center, Faculty of Engineering, Environment and Computing, Coventry University, Coventry, CV1 5FB, UK
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Garber L, Khodaei S, Maftoon N, Keshavarz-Motamed Z. Impact of TAVR on coronary artery hemodynamics using clinical measurements and image-based patient-specific in silico modeling. Sci Rep 2023; 13:8948. [PMID: 37268642 DOI: 10.1038/s41598-023-31987-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/21/2023] [Indexed: 06/04/2023] Open
Abstract
In recent years, transcatheter aortic valve replacement (TAVR) has become the leading method for treating aortic stenosis. While the procedure has improved dramatically in the past decade, there are still uncertainties about the impact of TAVR on coronary blood flow. Recent research has indicated that negative coronary events after TAVR may be partially driven by impaired coronary blood flow dynamics. Furthermore, the current technologies to rapidly obtain non-invasive coronary blood flow data are relatively limited. Herein, we present a lumped parameter computational model to simulate coronary blood flow in the main arteries as well as a series of cardiovascular hemodynamic metrics. The model was designed to only use a few inputs parameters from echocardiography, computed tomography and a sphygmomanometer. The novel computational model was then validated and applied to 19 patients undergoing TAVR to examine the impact of the procedure on coronary blood flow in the left anterior descending (LAD) artery, left circumflex (LCX) artery and right coronary artery (RCA) and various global hemodynamics metrics. Based on our findings, the changes in coronary blood flow after TAVR varied and were subject specific (37% had increased flow in all three coronary arteries, 32% had decreased flow in all coronary arteries, and 31% had both increased and decreased flow in different coronary arteries). Additionally, valvular pressure gradient, left ventricle (LV) workload and maximum LV pressure decreased by 61.5%, 4.5% and 13.0% respectively, while mean arterial pressure and cardiac output increased by 6.9% and 9.9% after TAVR. By applying this proof-of-concept computational model, a series of hemodynamic metrics were generated non-invasively which can help to better understand the individual relationships between TAVR and mean and peak coronary flow rates. In the future, tools such as these may play a vital role by providing clinicians with rapid insight into various cardiac and coronary metrics, rendering the planning for TAVR and other cardiovascular procedures more personalized.
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Affiliation(s)
- Louis Garber
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
| | - Seyedvahid Khodaei
- Department of Mechanical Engineering (Mail to JHE-310), McMaster University, Hamilton, ON, L8S 4L7, Canada
| | - Nima Maftoon
- Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada
- Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada
| | - Zahra Keshavarz-Motamed
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.
- Department of Mechanical Engineering (Mail to JHE-310), McMaster University, Hamilton, ON, L8S 4L7, Canada.
- School of Computational Science and Engineering, McMaster University, Hamilton, ON, Canada.
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7
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Zhang D, Lindsey SE. Recasting Current Knowledge of Human Fetal Circulation: The Importance of Computational Models. J Cardiovasc Dev Dis 2023; 10:240. [PMID: 37367405 PMCID: PMC10299027 DOI: 10.3390/jcdd10060240] [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: 04/15/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
Computational hemodynamic simulations are becoming increasingly important for cardiovascular research and clinical practice, yet incorporating numerical simulations of human fetal circulation is relatively underutilized and underdeveloped. The fetus possesses unique vascular shunts to appropriately distribute oxygen and nutrients acquired from the placenta, adding complexity and adaptability to blood flow patterns within the fetal vascular network. Perturbations to fetal circulation compromise fetal growth and trigger the abnormal cardiovascular remodeling that underlies congenital heart defects. Computational modeling can be used to elucidate complex blood flow patterns in the fetal circulatory system for normal versus abnormal development. We present an overview of fetal cardiovascular physiology and its evolution from being investigated with invasive experiments and primitive imaging techniques to advanced imaging (4D MRI and ultrasound) and computational modeling. We introduce the theoretical backgrounds of both lumped-parameter networks and three-dimensional computational fluid dynamic simulations of the cardiovascular system. We subsequently summarize existing modeling studies of human fetal circulation along with their limitations and challenges. Finally, we highlight opportunities for improved fetal circulation models.
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Affiliation(s)
| | - Stephanie E. Lindsey
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093, USA;
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8
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Evaluation of Different Cannulation Strategies for Aortic Arch Surgery Using a Cardiovascular Numerical Simulator. BIOENGINEERING (BASEL, SWITZERLAND) 2023; 10:bioengineering10010060. [PMID: 36671632 PMCID: PMC9854437 DOI: 10.3390/bioengineering10010060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/19/2022] [Accepted: 12/30/2022] [Indexed: 01/06/2023]
Abstract
Aortic disease has a significant impact on quality of life. The involvement of the aortic arch requires the preservation of blood supply to the brain during surgery. Deep hypothermic circulatory arrest is an established technique for this purpose, although neurological injury remains high. Additional techniques have been used to reduce risk, although controversy still remains. A three-way cannulation approach, including both carotid arteries and the femoral artery or the ascending aorta, has been used successfully for aortic arch replacement and redo procedures. We developed circuits of the circulation to simulate blood flow during this type of cannulation set up. The CARDIOSIM© cardiovascular simulation platform was used to analyse the effect on haemodynamic and energetic parameters and the benefit derived in terms of organ perfusion pressure and flow. Our simulation approach based on lumped-parameter modelling, pressure-volume analysis and modified time-varying elastance provides a theoretical background to a three-way cannulation strategy for aortic arch surgery with correlation to the observed clinical practice.
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Fan L, Sun Y, Choy JS, Kassab GS, Lee LC. Mechanism of exercise intolerance in heart diseases predicted by a computer model of myocardial demand-supply feedback system. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 227:107188. [PMID: 36334525 DOI: 10.1016/j.cmpb.2022.107188] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/28/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND AND OBJECTIVE The myocardial demand-supply feedback system plays an important role in augmenting blood supply in response to exercise-induced increased myocardial demand. During this feedback process, the myocardium and coronary blood flow interact bidirectionally at many different levels. METHODS To investigate these interactions, a novel computational framework that considers the closed myocardial demand-supply feedback system was developed. In the framework coupling the systemic circulation of the left ventricle and coronary perfusion with regulation, myocardial work affects coronary perfusion via flow regulation mechanisms (e.g., metabolic regulation) and myocardial-vessel interactions, whereas coronary perfusion affects myocardial contractility in a closed feedback system. The framework was calibrated based on the measurements from healthy subjects under graded exercise conditions, and then was applied to simulate the effects of graded exercise on myocardial demand-supply under different physiological and pathological conditions. RESULTS We found that the framework can recapitulate key features found during exercise in clinical and animal studies. We showed that myocardial blood flow is increased but maximum hyperemia is reduced during exercise, which led to a reduction in coronary flow reserve. For coronary stenosis and myocardial inefficiency, the model predicts that an increase in heart rate is necessary to maintain the baseline cardiac output. Correspondingly, the resting coronary flow reserve is exhausted and the range of heart rate before exhaustion of coronary flow reserve is reduced. In the presence of metabolic regulation dysfunction, the model predicts that the metabolic vasodilator signal is higher at rest, saturates faster during exercise, and as a result, causes quicker exhaustion of coronary flow reserve. CONCLUSIONS Model predictions showed that the coronary flow reserve deteriorates faster during graded exercise, which in turn, suggests a decrease in exercise tolerance for patients with stenosis, myocardial inefficiency and metabolic flow regulation dysfunction. The findings in this study may have clinical implications in diagnosing cardiovascular diseases.
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Affiliation(s)
- Lei Fan
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA.
| | - Yuexing Sun
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
| | - Jenny S Choy
- California Medical Innovations Institute, San Diego, CA, USA
| | | | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
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10
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Chaudhuri K, Pletzer A, Smith NP. A predictive patient-specific computational model of coronary artery bypass grafts for potential use by cardiac surgeons to guide selection of graft configurations. Front Cardiovasc Med 2022; 9:953109. [PMID: 36237904 PMCID: PMC9552835 DOI: 10.3389/fcvm.2022.953109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/01/2022] [Indexed: 01/09/2023] Open
Abstract
Cardiac surgeons face a significant degree of uncertainty when deciding upon coronary artery bypass graft configurations for patients with coronary artery disease. This leads to significant variation in preferred configuration between different surgeons for a particular patient. Additionally, for the majority of cases, there is no consensus regarding the optimal grafting strategy. This situation results in the tendency for individual surgeons to opt for a “one size fits all” approach and use the same grafting configuration for the majority of their patients neglecting the patient-specific nature of the diseased coronary circulation. Quantitative metrics to assess the adequacy of coronary bypass graft flows have recently been advocated for routine intraoperative use by cardiac surgeons. In this work, a novel patient-specific 1D-0D computational model called “COMCAB” is developed to provide the predictive haemodynamic parameters of functional graft performance that can aid surgeons to avoid configurations with grafts that have poor flow and thus poor patency. This model has significant potential for future expanded applications.
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Affiliation(s)
- Krish Chaudhuri
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Green Lane Cardiothoracic Surgical Unit, Auckland City Hospital, Auckland, New Zealand
- *Correspondence: Krish Chaudhuri,
| | | | - Nicolas P. Smith
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
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De Lazzari B, Badagliacca R, Filomena D, Papa S, Vizza CD, Capoccia M, De Lazzari C. CARDIOSIM©: The First Italian Software Platform for Simulation of the Cardiovascular System and Mechanical Circulatory and Ventilatory Support. Bioengineering (Basel) 2022; 9:bioengineering9080383. [PMID: 36004908 PMCID: PMC9404951 DOI: 10.3390/bioengineering9080383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
This review is devoted to presenting the history of the CARDIOSIM© software simulator platform, which was developed in Italy to simulate the human cardiovascular and respiratory systems. The first version of CARDIOSIM© was developed at the Institute of Biomedical Technologies of the National Research Council in Rome. The first platform version published in 1991 ran on a PC with a disk operating system (MS-DOS) and was developed using the Turbo Basic language. The latest version runs on PC with Microsoft Windows 10 operating system; it is implemented in Visual Basic and C++ languages. The platform has a modular structure consisting of seven different general sections, which can be assembled to reproduce the most important pathophysiological conditions. One or more zero-dimensional (0-D) modules have been implemented in the platform for each section. The different modules can be assembled to reproduce part or the whole circulation according to Starling’s law of the heart. Different mechanical ventilatory and circulatory devices have been implemented in the platform, including thoracic artificial lungs, ECMO, IABPs, pulsatile and continuous right and left ventricular assist devices, biventricular pacemakers and biventricular assist devices. CARDIOSIM© is used in clinical and educational environments.
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Affiliation(s)
- Beatrice De Lazzari
- Department of Human Movement and Sport Sciences, “Foro Italico” 4th University of Rome, 00135 Rome, Italy
- Correspondence:
| | - Roberto Badagliacca
- Department of Clinical, Internal Anesthesiology and Cardiovascular Sciences, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Domenico Filomena
- Department of Clinical, Internal Anesthesiology and Cardiovascular Sciences, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Silvia Papa
- Department of Clinical, Internal Anesthesiology and Cardiovascular Sciences, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Carmine Dario Vizza
- Department of Clinical, Internal Anesthesiology and Cardiovascular Sciences, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Massimo Capoccia
- Department of Cardiac Surgery, Leeds General Infirmary, Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK
- Department of Biomedical Engineering, University of Strathclyde, Glasgow G4 0NW, UK
| | - Claudio De Lazzari
- National Research Council, Institute of Clinical Physiology (IFC-CNR), 00185 Rome, Italy
- Faculty of Medicine, Teaching University Geomedi, Tbilisi 0114, Georgia
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12
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Sahoo KP, Dash A, Ghosh N, Patra A, Sinha A, Khandelwal S. Simulating Stenotic Conditions of the Coronary Artery in a Lumped Parameter Model of the Cardiovascular System. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:3993-3996. [PMID: 36086231 DOI: 10.1109/embc48229.2022.9871066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Coronary flow control mechanisms maintain the average coronary blood flow (CBF) at 4% of the cardiac output (CO) in normal adults, with no prior diagnosis of coronary artery disease (CAD), under resting conditions. This paper explores a pulsatile sixth order lumped parameter (LP) model of the cardiovascular system (CVS) which utilizes the average CBF approximated from CO along with arterial blood pressure (ABP) waveform to estimate the coronary microvascular resistance using non-linear least square optimization technique. The CVS model includes a third order model of the coronary vascular bed and is shown to achieve phasic coronary flow. The coronary epicardial resistance is varied to emulate different degrees of stenosis and achieve realistic behavior of coronary microvascular resistance under these conditions.
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13
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Fractional Flow Reserve (FFR) Estimation from OCT-Based CFD Simulations: Role of Side Branches. APPLIED SCIENCES-BASEL 2022; 12. [PMID: 36313242 PMCID: PMC9611764 DOI: 10.3390/app12115573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The computational fluid dynamic method has been widely used to quantify the hemodynamic alterations in a diseased artery and investigate surgery outcomes. The artery model reconstructed based on optical coherence tomography (OCT) images generally does not include the side branches. However, the side branches may significantly affect the hemodynamic assessment in a clinical setting, i.e., the fractional flow reserve (FFR), defined as the ratio of mean distal coronary pressure to mean aortic pressure. In this work, the effect of the side branches on FFR estimation was inspected with both idealized and optical coherence tomography (OCT)-reconstructed coronary artery models. The electrical analogy of blood flow was further used to understand the impact of the side branches (diameter and location) on FFR estimation. Results have shown that the side branches decrease the total resistance of the vessel tree, resulting in a higher inlet flowrate. The side branches located at the downstream of the stenosis led to a lower FFR value, while the ones at the upstream had a minimal impact on the FFR estimation. Side branches with a diameter larger than one third of the main vessel diameter are suggested to be considered for a proper FFR estimation. The findings in this study could be extended to other coronary artery imaging modalities and facilitate treatment planning.
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14
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Structure (Epicardial Stenosis) and Function (Microvascular Dysfunction) That Influence Coronary Fractional Flow Reserve Estimation. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12094281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Background. The treatment of coronary stenosis is decided by performing high risk invasive surgery to generate the fractional flow reserve diagnostics index, a ratio of distal to proximal pressures in respect of coronary atherosclerotic plaques. Non-invasive methods are a need of the times that necessitate the use of mathematical models of coronary hemodynamic physiology. This study proposes an extensible mathematical description of the coronary vasculature that provides an estimate of coronary fractional flow reserve. Methods. By adapting an existing computational model of human coronary blood flow, the effects of large vessel stenosis and microvascular disease on fractional flow reserve were quantified. Several simulations generated flow and pressure information, which was used to compute fractional flow reserve under several conditions including focal stenosis, diffuse stenosis, and microvascular disease. Sensitivity analysis was used to uncover the influence of model parameters on fractional flow reserve. The model was simulated as coupled non-linear ordinary differential equations and numerically solved using our implicit higher order method. Results. Large vessel stenosis affected fractional flow reserve. The model predicts that the presence, rather than severity, of microvascular disease affects coronary flow deleteriously. Conclusions. The model provides a computationally inexpensive instrument for future in silico coronary blood flow investigations as well as clinical-imaging decision making. A combination of focal and diffuse stenosis appears to be essential to limit coronary flow. In addition to pressure measurements in the large epicardial vessels, diagnosis of microvascular disease is essential. The independence of the index with respect to heart rate suggests that computationally inexpensive steady state simulations may provide sufficient information to reliably compute the index.
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15
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Li Z, Chen Y, Zeng X, Stephen S, Li Y, Li H, Dong L, He T, Zhang S, Yang P, Jiang W, Fan H. Clinical and hemodynamic insights into the use of internal iliac artery balloon occlusion as a prophylactic technique for treating postpartum hemorrhage. J Biomech 2021; 129:110827. [PMID: 34736088 DOI: 10.1016/j.jbiomech.2021.110827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/02/2021] [Accepted: 10/16/2021] [Indexed: 11/19/2022]
Abstract
Recently, the effectiveness of internal iliac artery balloon occlusion (IIABO) for treating postpartum hemorrhage caused by pernicious placenta previa (PPP) has been questioned. We conducted a retrospective analysis and hemodynamic simulation to assess the IIABO's effectiveness. The retrospective analysis involved 480 patients with PPP, among which 288 underwent IIABO treatment and the remaining 192 were used as controls. Blood loss and preoperative indicators were recorded, and multiple regression analysis was applied to test the effect of preoperative indicators on blood loss. Hemorrhage mechanisms were simulated using a numerical model. Results suggested that no significant difference in blood loss (1836 ± 1440 ml vs. 1784 ± 1647 ml, p = 0.22) was observed between the two groups. In addition, preoperative indicators, including age, weight, gestational age, gravidity, parity, blood type, anemia, or diabetes, were not associated with blood loss. In the simulation, after the intra-iliac artery was blocked, blood loss was caused by a reversed flow in the intrapelvic arteries, uterine veins, and uterine venules. The ratio of the time-averaged hemorrhage velocity (TAHV) in the balloon group to that in the control group was lower than that obtained in a clinical study (13.0% vs. 88.9%); in the presence of collateral circulation, blood loss occurred from collateral circulation and uterine venules after IIABO intervention, and the TAHV was 60%-90% that of the control group, which was closer to the clinical results (88.9%). These results suggest that IIABO cannot effectively treat postpartum hemorrhage because of the collateral circulation and reversed flow in the uterine venules.
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Affiliation(s)
- Zhongyou Li
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yu Chen
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China; Medical Big Data Center, Sichuan University, Chengdu 610041, China.
| | - Xiaoxi Zeng
- Medical Big Data Center, Sichuan University, Chengdu 610041, China
| | - Salerno Stephen
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Yi Li
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Huafeng Li
- West China Second Hospital, Sichuan University, Chengdu 610041, China.
| | - Lihua Dong
- Department of Anatomy, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China
| | - Teng He
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Shihong Zhang
- West China Second Hospital, Sichuan University, Chengdu 610041, China
| | - Pei Yang
- West China Second Hospital, Sichuan University, Chengdu 610041, China
| | - Wentao Jiang
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Haidong Fan
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
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16
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A validated reduced-order dynamic model of nitric oxide regulation in coronary arteries. Comput Biol Med 2021; 139:104958. [PMID: 34717232 DOI: 10.1016/j.compbiomed.2021.104958] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 09/30/2021] [Accepted: 10/16/2021] [Indexed: 01/15/2023]
Abstract
Nitric Oxide (NO) provides myocardial oxygen demands of the heart during exercise and cardiac pacing and also prevents cardiovascular diseases such as atherosclerosis and platelet adhesion and aggregation. However, the direct in vivo measurement of NO in coronary arteries is still challenging. To address this matter, a mathematical model of dynamic changes of calcium and NO concentration in the coronary artery was developed for the first time. The model is able to simulate the effect of NO release in coronary arteries and its impact on the hemodynamics of the coronary arterial tree and also to investigate the vasodilation effects of arteries during cardiac pacing. For these purposes, flow rate, time-averaged wall shear stress, dilation percent, NO concentration, and Calcium (Ca2+) concentration within coronary arteries were obtained. In addition, the impact of hematocrit on the flow rate of the coronary artery was studied. It was seen that the behavior of flow rate, wall shear stress, and Ca2+ is biphasic, but the behavior of NO concentration and the dilation percent is triphasic. Also, by increasing the Hematocrit, the blood flow reduces slightly. The results were compared with several experimental measurements to validate the model qualitatively and quantitatively. It was observed that the presented model is well capable of predicting the behavior of arteries after releasing NO during cardiac pacing. Such a study would be a valuable tool to understand the mechanisms underlying vessel damage, and thereby to offer insights for the prevention or treatment of cardiovascular diseases.
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17
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Lyras KG, Lee J. An improved reduced-order model for pressure drop across arterial stenoses. PLoS One 2021; 16:e0258047. [PMID: 34597313 PMCID: PMC8486142 DOI: 10.1371/journal.pone.0258047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 09/16/2021] [Indexed: 11/19/2022] Open
Abstract
Quantification of pressure drop across stenotic arteries is a major element in the functional assessment of occlusive arterial disease. Accurate estimation of the pressure drop with a numerical model allows the calculation of Fractional Flow Reserve (FFR), which is a haemodynamic index employed for guiding coronary revascularisation. Its non-invasive evaluation would contribute to safer and cost-effective diseases management. In this work, we propose a new formulation of a reduced-order model of trans-stenotic pressure drop, based on a consistent theoretical analysis of the Navier-Stokes equation. The new formulation features a novel term that characterises the contribution of turbulence effect to pressure loss. Results from three-dimensional computational fluid dynamics (CFD) showed that the proposed model produces predictions that are significantly more accurate than the existing reduced-order models, for large and small symmetric and eccentric stenoses, covering mild to severe area reductions. FFR calculations based on the proposed model produced zero classification error for three classes comprising positive (≤ 0.75), negative (≥ 0.8) and intermediate (0.75 − 0.8) classes.
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Affiliation(s)
- Konstantinos G. Lyras
- School of Biomedical Engineering & Imaging Sciences, King’s College London, London, United Kingdom
- * E-mail: (KGL); (JL)
| | - Jack Lee
- School of Biomedical Engineering & Imaging Sciences, King’s College London, London, United Kingdom
- * E-mail: (KGL); (JL)
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18
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Baiocchi M, Barsoum S, Khodaei S, de la Torre Hernandez JM, Valentino SE, Dunford EC, MacDonald MJ, Keshavarz-Motamed Z. Effects of Choice of Medical Imaging Modalities on a Non-invasive Diagnostic and Monitoring Computational Framework for Patients With Complex Valvular, Vascular, and Ventricular Diseases Who Undergo Transcatheter Aortic Valve Replacement. Front Bioeng Biotechnol 2021; 9:643453. [PMID: 34307316 PMCID: PMC8297508 DOI: 10.3389/fbioe.2021.643453] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Due to the high individual differences in the anatomy and pathophysiology of patients, planning individualized treatment requires patient-specific diagnosis. Indeed, hemodynamic quantification can be immensely valuable for accurate diagnosis, however, we still lack precise diagnostic methods for numerous cardiovascular diseases including complex (and mixed) valvular, vascular, and ventricular interactions (C3VI) which is a complicated situation made even more challenging in the face of other cardiovascular pathologies. Transcatheter aortic valve replacement (TAVR) is a new less invasive intervention and is a growing alternative for patients with aortic stenosis. In a recent paper, we developed a non-invasive and Doppler-based diagnostic and monitoring computational mechanics framework for C3VI, called C3VI-DE that uses input parameters measured reliably using Doppler echocardiography. In the present work, we have developed another computational-mechanics framework for C3VI (called C3VI-CT). C3VI-CT uses the same lumped-parameter model core as C3VI-DE but its input parameters are measured using computed tomography and a sphygmomanometer. Both frameworks can quantify: (1) global hemodynamics (metrics of cardiac function); (2) local hemodynamics (metrics of circulatory function). We compared accuracy of the results obtained using C3VI-DE and C3VI-CT against catheterization data (gold standard) using a C3VI dataset (N = 49) for patients with C3VI who undergo TAVR in both pre and post-TAVR with a high variability. Because of the dataset variability and the broad range of diseases that it covers, it enables determining which framework can yield the most accurate results. In contrast with C3VI-CT, C3VI-DE tracks both the cardiac and vascular status and is in great agreement with cardiac catheter data.
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Affiliation(s)
- Melissa Baiocchi
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada
| | - Shirley Barsoum
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada
| | - Seyedvahid Khodaei
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada
| | | | | | - Emily C Dunford
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | | | - Zahra Keshavarz-Motamed
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.,School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.,School of Computational Science and Engineering, McMaster University, Hamilton, ON, Canada
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19
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Zhang H, Xia J, Yang Y, Yang Q, Song H, Xie J, Ma Y, Hou Y, Qiao A. Branch flow distribution approach and its application in the calculation of fractional flow reserve in stenotic coronary artery. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:5978-5994. [PMID: 34517519 DOI: 10.3934/mbe.2021299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
OBJECTIVE To calculate fractional flow reserve (FFR) based on computed tomography angiography (i.e., FFRCT) by considering the branch flow distribution in the coronary arteries. BACKGROUND FFR is the gold standard to diagnose myocardial ischemia caused by coronary stenosis. An accurate and noninvasive method for obtaining total coronary blood flow is needed for the calculation of FFRCT. METHODS A mathematical model for estimating the coronary blood flow rate and two approaches for setting the patient-specific flow boundary condition were proposed. Coronary branch flow distribution methods based on a volume-flow approach and a diameter-flow approach were employed for the numerical simulation of FFRCT. The values of simulated FFRCT for 16 patients were compared with their clinically measured FFR. RESULTS The ratio of total coronary blood flow to cardiac output and the myocardial blood flow under the condition of hyperemia were 16.97% and 4.07 mL/min/g, respectively. The errors of FFRCT compared with clinical data under the volume-flow approach and diameter-flow approach were 10.47% and 11.76%, respectively, the diagnostic accuracies of FFRCT were 65% and 85%, and the consistencies were 95% and 90%. CONCLUSIONS The mathematical model for estimating the coronary blood flow rate and the coronary branch flow distribution method can be applied to calculate the value of clinical noninvasive FFRCT.
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Affiliation(s)
- Honghui Zhang
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
- Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing 100124, China
| | - Jun Xia
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
- Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing 100124, China
| | - Yinlong Yang
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
- Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing 100124, China
| | - Qingqing Yang
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
- Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing 100124, China
| | - Hongfang Song
- School of Biomedical Engineering, Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Jinjie Xie
- Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Yue Ma
- Shengjing Hospital, China Medical University, Shenyang 110001, China
| | - Yang Hou
- Shengjing Hospital, China Medical University, Shenyang 110001, China
| | - Aike Qiao
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
- Intelligent Physiological Measurement and Clinical Translation, Beijing International Base for Scientific and Technological Cooperation, Beijing 100124, China
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20
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Tobin JM. Toward an Electrical Analog of the Cardiovascular System in Hemorrhage. Cardiovasc Eng Technol 2021; 12:526-529. [PMID: 34018154 DOI: 10.1007/s13239-021-00545-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 05/12/2021] [Indexed: 11/25/2022]
Abstract
Current quantitative descriptions of the cardiovascular system in hemorrhagic shock focus on pressure based metrics. This approach is often incomplete; overlooking the important role of tissue perfusion. Electrical analogs to the cardiovascular system may offer a more complete description of hemorrhage. Application of fundamental concepts in electrical circuit theory (i.e.; Kirchhoff's Voltage Law and Ohm's Law) to analogs of the cardiovascular system offers a more refined description of this complex process. This manuscript hopes to serve as a starting point for a more mathematically robust, and clinically relevant description of hemorrhagic shock.
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Affiliation(s)
- Joshua M Tobin
- Department of Anesthesiology, Stanford University, Palo Alto, CA, USA.
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21
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Civilla L, Sbrollini A, Burattini L, Morettini M. An integrated lumped-parameter model of the cardiovascular system for the simulation of acute ischemic stroke: description of instantaneous changes in hemodynamics. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:3993-4010. [PMID: 34198422 DOI: 10.3934/mbe.2021200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Acute Ischemic Stroke (AIS) is defined as the acute condition of occlusion of a cerebral artery and is often caused by a Hypertensive Condition (HC). Due to its sudden occurrence, AIS is not observable the right moment it occurs, thus information about instantaneous changes in hemodynamics is limited. This study aimed to propose an integrated Lumped Parameter (LP) model of the cardiovascular system to simulate an AIS and describe instantaneous changes in hemodynamics. In the integrated LP model of the cardiovascular system, heart chambers have been modelled with elastance systems with controlled pressure inputs; heart valves have been modelled with static open/closed pressure-controlled valves; eventually, the vasculature has been modelled with resistor-inductor-capacitor (RLC) direct circuits and have been linked to the rest of the system through a series connection. After simulating physiological conditions, HC has been simulated by changing pressure inputs and constant RLC parameters. Then, AIS occurring in arteries of different sizes have been simulated by considering time-dependent RLC parameters due to the elimination from the model of the occluding artery; instantaneous changes in hemodynamics have been evaluated by Systemic Arteriolar Flow (Qa) and Systemic Arteriolar Pressure (Pa) drop with respect to those measured in HC. Occlusion of arteries of different sizes leaded to an average Qa drop of 0.38 ml/s per cardiac cycle (with minimum and maximum values of 0.04 ml/s and 1.93 ml/s) and average Pa drop of 0.39 mmHg, (with minimum and maximum values of 0.04 mmHg and 1.98 mmHg). In conclusion, hemodynamic variations due to AIS are very small with respect to HC. A direct relation between the inverse of the length of the artery in which the occlusion occurs and the hemodynamic variations has been highlighted; this may allow to link the severity of AIS to the length of the interested artery.
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Affiliation(s)
- Lorenzo Civilla
- Department of Information Engineering, UniversitȤ Politecnica delle Marche, Ancona 60131, Italy
| | - Agnese Sbrollini
- Department of Information Engineering, UniversitȤ Politecnica delle Marche, Ancona 60131, Italy
| | - Laura Burattini
- Department of Information Engineering, UniversitȤ Politecnica delle Marche, Ancona 60131, Italy
| | - Micaela Morettini
- Department of Information Engineering, UniversitȤ Politecnica delle Marche, Ancona 60131, Italy
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22
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Li Z, Jiang W, Salerno S, Li Y, Chen Y, Xu Z, Wang G. Acute Hemodynamic Improvement by Thermal Vasodilation inside the Abdominal and Iliac Arterial Segments of Young Sedentary Individuals. J Vasc Res 2021; 58:191-206. [PMID: 33823509 DOI: 10.1159/000514588] [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: 09/17/2020] [Accepted: 01/19/2021] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To study the hemodynamic response to lower leg heating intervention (LLHI) inside the abdominal and iliac arterial segments (AIAS) of young sedentary individuals. METHODS A Doppler measurement of blood flow was conducted for 5 young sedentary adults with LLHI. Heating durations of 0, 20, and 40 min were considered. A lumped parameter model (LPM) was used to ascertain the hemodynamic mechanism. The hemodynamics were determined via numerical approaches. RESULTS Ultrasonography revealed that the blood flow waveform shifted upwards under LLHI; in particular, the mean flow increased significantly (p < 0.05) with increasing heating duration. The LPM showed that its mechanism depends on the reduction in afterload resistance, not on the inertia of blood flow and arterial compliance. The time-averaged wall shear stress, time-averaged production rate of nitric oxide, and helicity in the external iliac arteries increased more significantly than in other segments as the heating duration increased, while the oscillation shear index (OSI) and relative residence time (RRT) in the AIAS declined with increasing heating duration. There was a more obvious helicity response in the bilateral external iliac arteries than the OSI and RRT responses. CONCLUSION LLHI can effectively induce a positive hemodynamic environment in the AIAS of young sedentary individuals.
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Affiliation(s)
- Zhongyou Li
- Laboratory of Biomechanical Engineering, Department of Applied Mechanics, College of Architecture & Environment, Sichuan University, Chengdu, China
| | - Wentao Jiang
- Laboratory of Biomechanical Engineering, Department of Applied Mechanics, College of Architecture & Environment, Sichuan University, Chengdu, China
| | - Stephen Salerno
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, USA
| | - Yi Li
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, USA
| | - Yu Chen
- Laboratory of Biomechanical Engineering, Department of Applied Mechanics, College of Architecture & Environment, Sichuan University, Chengdu, China
| | - Zhi Xu
- Laboratory of Biomechanical Engineering, Department of Applied Mechanics, College of Architecture & Environment, Sichuan University, Chengdu, China.,Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
| | - Guanshi Wang
- Laboratory of Biomechanical Engineering, Department of Applied Mechanics, College of Architecture & Environment, Sichuan University, Chengdu, China
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23
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Khan AS, Shahzad A, Zubair M, Alvi A, Gul R. Personalized 0D models of normal and stenosed carotid arteries. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 200:105888. [PMID: 33293184 DOI: 10.1016/j.cmpb.2020.105888] [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: 09/07/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Recent advances in medical imaging like MRI, CT-Scan, Doppler ultrasound, etc. have made it possible to study the hemodynamics of cardiovascular system having different levels of vessel abnormalities. METHODS Within this work, we have developed two different personalized lumped-parameter models of the human carotid arteries having elastic and viscoelastic vessel wall behaviors. The data used in developing the models of the carotid arteries is taken from a healthy subject and a patient having mild carotid stenosis (55%) near a bifurcation using doppler ultrasound. The data consists measurements of blood flow velocities and geometrical parameters at selected locations. Prior to the measurements, the key measurable geometrical parameters are identified by normalized local sensitivity analysis. RESULTS Finally, both developed and personalized models of carotid arteries are validated against the blood flow measurements obtained near carotid bifurcation. We observe a good agreement between model simulations and blood flow measurements taken near the bifurcation i.e. (r=0.94) for the healthy subject and (r=0.96) for the patient having a stenosis near the bifurcation. CONCLUSIONS This work provides further evidence, that the hemodynamics near a bifurcation can be modelled well with a 0D approach, even with different levels of stenosis.
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Affiliation(s)
| | - Aamir Shahzad
- COMSATS University Islamabad, Abbottabad Campus, Pakistan
| | | | | | - Raheem Gul
- COMSATS University Islamabad, Abbottabad Campus, Pakistan.
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24
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Rosalia L, Ozturk C, Van Story D, Horvath MA, Roche ET. Object‐Oriented Lumped‐Parameter Modeling of the Cardiovascular System for Physiological and Pathophysiological Conditions. ADVANCED THEORY AND SIMULATIONS 2021. [DOI: 10.1002/adts.202000216] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Luca Rosalia
- Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA
- Harvard‐MIT Program in Health Sciences and Technology Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - Caglar Ozturk
- Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - David Van Story
- Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - Markus A. Horvath
- Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA
- Harvard‐MIT Program in Health Sciences and Technology Massachusetts Institute of Technology Cambridge MA 02139 USA
| | - Ellen T. Roche
- Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA
- Harvard‐MIT Program in Health Sciences and Technology Massachusetts Institute of Technology Cambridge MA 02139 USA
- Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA
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25
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Fan L, Namani R, Choy JS, Awakeem Y, Kassab GS, Lee LC. Role of coronary flow regulation and cardiac-coronary coupling in mechanical dyssynchrony associated with right ventricular pacing. Am J Physiol Heart Circ Physiol 2020; 320:H1037-H1054. [PMID: 33356963 DOI: 10.1152/ajpheart.00549.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanical dyssynchrony (MD) affects left ventricular (LV) mechanics and coronary perfusion. To understand the multifactorial effects of MD, we developed a computational model that bidirectionally couples the systemic circulation with the LV and coronary perfusion with flow regulation. In the model, coronary flow in the left anterior descending (LAD) and left circumflex (LCX) arteries affects the corresponding regional contractility based on a prescribed linear LV contractility-coronary flow relationship. The model is calibrated with experimental measurements of LV pressure and volume, as well as LAD and LCX flow rate waveforms acquired under regulated and fully dilated conditions from a swine under right atrial (RA) pacing. The calibrated model is applied to simulate MD. The model can simultaneously reproduce the reduction in mean LV pressure (39.3%), regulated flow (LAD: 7.9%; LCX: 1.9%), LAD passive flow (21.6%), and increase in LCX passive flow (15.9%). These changes are associated with right ventricular pacing compared with RA pacing measured in the same swine only when LV contractility is affected by flow alterations with a slope of 1.4 mmHg/mL2 in a contractility-flow relationship. In sensitivity analyses, the model predicts that coronary flow reserve (CFR) decreases and increases in the LAD and LCX with increasing delay in LV free wall contraction. These findings suggest that asynchronous activation associated with MD impacts 1) the loading conditions that further affect the coronary flow, which may explain some of the changes in CFR, and 2) the coronary flow that reduces global contractility, which contributes to the reduction in LV pressure.NEW & NOTEWORTHY A computational model that couples the systemic circulation of the left ventricular (LV) and coronary perfusion with flow regulation is developed to study the effects of mechanical dyssynchrony. The delayed contraction in the LV free wall with respect to the septum has a significant effect on LV function and coronary flow reserve.
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Affiliation(s)
- Lei Fan
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan
| | - Ravi Namani
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan
| | - Jenny S Choy
- California Medical Innovation Institute, San Diego, California
| | - Yousif Awakeem
- California Medical Innovation Institute, San Diego, California
| | | | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan
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26
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Li B, Wang H, Li G, Liu J, Zhang Z, Gu K, Yang H, Qiao A, Du J, Liu Y. A patient-specific modelling method of blood circulatory system for the numerical simulation of enhanced external counterpulsation. J Biomech 2020; 111:110002. [PMID: 32898825 DOI: 10.1016/j.jbiomech.2020.110002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/09/2020] [Accepted: 08/14/2020] [Indexed: 11/17/2022]
Abstract
Lumped parameter model (LPM) is a common numerical model for hemodynamic simulation of human's blood circulatory system. The numerical simulation of enhanced external counterpulsation (EECP) is a typical biomechanical simulation process based on the LPM of blood circulatory system. In order to simulate patient-specific hemodynamic effects of EECP and develop best treatment strategy for each individual, this study developed an optimization algorithm to individualize LPM elements. Physiological data from 30 volunteers including approximate aortic pressure, cardiac output, ankle pressure and carotid artery flow were clinically collected as optimization objectives. A closed-loop LPM was established for the simulation of blood circulatory system. Aiming at clinical data, a sensitivity analysis for each element was conducted to identify the significant ones. We improved the traditional simulated annealing algorithm to iteratively optimize the sensitive elements. To verify the accuracy of the patient-specific model, 30 samples of simulated data were compared with clinical measurements. In addition, an EECP experiment was conducted on a volunteer to verify the applicability of the optimized model for the simulation of EECP. For these 30 samples, the optimization results show a slight difference between clinical data and simulated data. The average relative root mean square error is lower than 5%. For the subject of EECP experiment, the relative error of hemodynamic responses during EECP is lower than 10%. This slight error demonstrated a good state of optimization. The optimized modeling algorithm can effectively individualize the LPM for blood circulatory system, which is significant to the numerical simulation of patient-specific hemodynamics.
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Affiliation(s)
- Bao Li
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China.
| | - Hui Wang
- The Eighth Affiliated Hospital, Sun Yat-sen University, ShenZhen, GuangDong, China
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan
| | - Jian Liu
- Peking University People's Hospital, Beijing, China
| | - Zhe Zhang
- Peking University Third Hospital, Beijing, China
| | - Kaiyun Gu
- Peking University Third Hospital, Beijing, China
| | - Haisheng Yang
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Aike Qiao
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Jianhang Du
- The Eighth Affiliated Hospital, Sun Yat-sen University, ShenZhen, GuangDong, China
| | - Youjun Liu
- Department of Biomedical Engineering, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China.
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27
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Fan L, Namani R, Choy JS, Kassab GS, Lee LC. Effects of Mechanical Dyssynchrony on Coronary Flow: Insights From a Computational Model of Coupled Coronary Perfusion With Systemic Circulation. Front Physiol 2020; 11:915. [PMID: 32922304 PMCID: PMC7457036 DOI: 10.3389/fphys.2020.00915] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/08/2020] [Indexed: 01/01/2023] Open
Abstract
Mechanical dyssynchrony affects left ventricular (LV) mechanics and coronary perfusion. Due to the confounding effects of their bi-directional interactions, the mechanisms behind these changes are difficult to isolate from experimental and clinical studies alone. Here, we develop and calibrate a closed-loop computational model that couples the systemic circulation, LV mechanics, and coronary perfusion. The model is applied to simulate the impact of mechanical dyssynchrony on coronary flow in the left anterior descending artery (LAD) and left circumflex artery (LCX) territories caused by regional alterations in perfusion pressure and intramyocardial pressure (IMP). We also investigate the effects of regional coronary flow alterations on regional LV contractility in mechanical dyssynchrony based on prescribed contractility-flow relationships without considering autoregulation. The model predicts that LCX and LAD flows are reduced by 7.2%, and increased by 17.1%, respectively, in mechanical dyssynchrony with a systolic dyssynchrony index of 10% when the LAD's IMP is synchronous with the arterial pressure. The LAD flow is reduced by 11.6% only when its IMP is delayed with respect to the arterial pressure by 0.07 s. When contractility is sensitive to coronary flow, mechanical dyssynchrony can affect global LV mechanics, IMPs and contractility that in turn, further affect the coronary flow in a feedback loop that results in a substantial reduction of dPLV/dt, indicative of ischemia. Taken together, these findings imply that regional IMPs play a significant role in affecting regional coronary flows in mechanical dyssynchrony and the changes in regional coronary flow may produce ischemia when contractility is sensitive to the changes in coronary flow.
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Affiliation(s)
- Lei Fan
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
| | - Ravi Namani
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
| | - Jenny S Choy
- California Medical Innovation Institute, San Diego, CA, United States
| | - Ghassan S Kassab
- California Medical Innovation Institute, San Diego, CA, United States
| | - Lik Chuan Lee
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
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28
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A diagnostic, monitoring, and predictive tool for patients with complex valvular, vascular and ventricular diseases. Sci Rep 2020; 10:6905. [PMID: 32327673 PMCID: PMC7181740 DOI: 10.1038/s41598-020-63728-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/31/2020] [Indexed: 01/03/2023] Open
Abstract
Hemodynamics quantification is critically useful for accurate and early diagnosis, but we still lack proper diagnosticmethods for many cardiovascular diseases. Furthermore, as most interventions intend to recover the healthy condition, the ability to monitor and predict hemodynamics following interventions can have significant impacts on saving lives. Predictive methods are rare, enabling prediction of effects of interventions, allowing timely and personalized interventions and helping critical clinical decision making about life-threatening risks based on quantitative data. In this study, an innovative non-invasive imaged-based patient-specific diagnostic, monitoring and predictive tool (called C3VI-CMF) was developed, enabling quantifying (1) details of physiological flow and pressures through the heart and circulatory system; (2) heart function metrics. C3VI-CMF also predicts the breakdown of the effects of each disease constituents on the heart function. Presently, neither of these can be obtained noninvasively in patients and when invasive procedures are undertaken, the collected metrics cannot be by any means as complete as the ones C3VI-CMF provides. C3VI-CMF purposefully uses a limited number of noninvasive input parameters all of which can be measured using Doppler echocardiography and sphygmomanometer. Validation of C3VI-CMF, against cardiac catheterization in forty-nine patients with complex cardiovascular diseases, showed very good agreement with the measurements.
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29
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Fu Y, Qiao A, Yang Y, Fan X. Numerical Simulation of the Effect of Pulmonary Vascular Resistance on the Hemodynamics of Reoperation After Failure of One and a Half Ventricle Repair. Front Physiol 2020; 11:207. [PMID: 32256381 PMCID: PMC7090855 DOI: 10.3389/fphys.2020.00207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/21/2020] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE The one and a half ventricle repair (1.5VR) is a common clinical choice for patients with right heart dysfunction. Considering the influence of blood circulation failure and reoperation in urgent need, this essay aims to explore the hemodynamic effects of different pulmonary vascular resistance (PVR) values on reoperation after 1.5VR failure. METHODS The lumped parameter model (LPM) was used to simulate the reoperation, including the return biventricular repair (2VR), ligation of azygos vein (1.5VR') and return single ventricular repair (1.0VR). Firstly, the debugging parameters were used to simulate the hemodynamics of 2VR. Secondly, the value of PVR was changed from one to four times while the other parameters remained unchanged. Finally, 15 cardiac cycles were simulated and the 15th result was obtained. In this work, the left and right ventricular stroke work and their sum (Plv, Prv, Ptotal), the left and right ventricular ejection fraction (LVEF, RVEF), the mean Cardiac Output (mCO) and the mean pressure and flow-rate ratio of superior and inferior vena cava (mPsvc\mPivc and mQsvc\mQivc), respectively, were used to describe the hemodynamics of reoperation. RESULTS With the change of PVR from one to four times, the values of Plv, Prv, Ptotal, LVEF, and RVEF gradually decreased. The change rate of Plv, Ptotal and LVEF of 1.0VR were the largest in the three kinds of reoperation. The change rate of Prv of 1.5VR' was larger than that of 2VR, but it was the opposite for their EF change rate. The mCO of 2VR, 1.5VR', and 1.0VR decreased by 18.53%, 37.58%, and 48.07%, respectively. The mPsvc\mPivc of 1.5VR' increased from 3.76 to 6.77 and the mQsvc\mQivc decreased from 0.55 to 0.36, while the mPsvc\mPivc and mQsvc\mQivc of 2VR and 1.0VR remained 1 and 0.67, respectively. The peak value of the tricuspid flow-rate (Qti) waveform of 2VR and 1.5VR' changed from "E peak" to "A peak." CONCLUSION The numerical results demonstrate the highly reoperation-dependent hemodynamic consequences and their responses to variations in PVR. Comprehensive analysis of EF, mCO and ventricular stroke work indicates that PVR has a greater impact on 1.5VR' and 1.0VR. Therefore, we suggest that the selection strategy of reoperation should focus on PVR.
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Affiliation(s)
- Yan Fu
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Aike Qiao
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Yao Yang
- Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xiangming Fan
- Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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30
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Lee Y, Veerubhotla K, Jeong MH, Lee CH. Deep Learning in Personalization of Cardiovascular Stents. J Cardiovasc Pharmacol Ther 2020; 25:110-120. [DOI: 10.1177/1074248419878405] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Deep learning (DL) application has demonstrated its enormous potential in accomplishing biomedical tasks, such as vessel segmentation, brain visualization, and speech recognition. This review article has mainly covered recent advances in the principles of DL algorithms, existing DL software, and designing strategies of DL models. Latest progresses in cardiovascular devices, especially DL-based cardiovascular stent used for angioplasty, differential and advanced diagnostic means, and the treatment outcomes involved with coronary artery disease (CAD), are discussed. Also presented is DL-based discovery of new materials and future medical technologies that will facilitate the development of tailored and personalized treatment strategies by identifying and forecasting individual impending risks of cardiovascular diseases.
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Affiliation(s)
- Yugyung Lee
- School of Computing and Engineering, University of Missouri-Kansas City, MO, USA
| | - Krishna Veerubhotla
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, MO, USA
| | - Myung Ho Jeong
- Department of Cardiovascular Medicine of Chonnam National University, Gwang-Ju, South Korea
| | - Chi H. Lee
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, MO, USA
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31
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Faes TJC, Meer R, Heyndrickx GR, Kerkhof PLM. Fractional Flow Reserve Evaluated as Metric of Coronary Stenosis - A Mathematical Model Study. Front Cardiovasc Med 2020; 6:189. [PMID: 31993441 PMCID: PMC6970943 DOI: 10.3389/fcvm.2019.00189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 12/11/2019] [Indexed: 12/20/2022] Open
Abstract
Introduction: Coronary arterial stenosis may impair myocardial perfusion with myocardial ischemia and associated morbidity and mortality as result. The myocardial fractional flow reserve (FFR) is clinically used as a stenosis-specific index. Aim: This study aims to identify the relation between the FFR and the degree of coronary arterial stenosis using a simple mathematical model of the coronary circulation. Methods: A mathematical model of the coronary circulation, including an arterial stenosis of variable degree, was developed. The relation between the FFR and the degree of stenosis (defined as the fractional cross sectional area narrowing) was investigated, including the influence of the aortic and venous pressures and the capillary resistance. An additional study concerning 22 patients with coronary artery disease permits comparison of clinical data and in silico findings. Results: The FFR shows an S-shaped relationship with the stenosis index. We found a marked influence of venous and aortic pressure and capillary resistance. The FFR is accompanied by a clinically relevant co-metric (FFR C ), defined by the Pythagorean sum of the two pressures in the definition formula for FFR. In the patient group the FFR C is strongly related to the post-stenotic pressure (R = 0.91). The FFR C requires establishment of a validated cut-off point using future trials. Conclusion: The S-shaped dependence of FFR on the severity of the stenosis makes the FFR a measure of the ordinal scale. The marked influences of the aortic and venous pressures and the capillary resistance on the FFR will be interpreted as significant variations in intra- and inter-individual clinical findings. These fluctuations are partly connected to the neglect of considering the FFR C . At otherwise identical conditions the FFR as measured at baseline differs from the value obtained during hyperemic conditions. This expected observation requires further investigation, as the current hyperemia based evaluation fails to take advantage of available baseline data.
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Affiliation(s)
- Theo J. C. Faes
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Romain Meer
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | | | - Peter L. M. Kerkhof
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, Amsterdam, Netherlands
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32
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Altamirano-Diaz L, Kassay AD, Serajelahi B, McIntyre CW, Filler G, Kharche SR. Arterial Hypertension and Unusual Ascending Aortic Dilatation in a Neonate With Acute Kidney Injury: Mechanistic Computer Modeling. Front Physiol 2019; 10:1391. [PMID: 31780955 PMCID: PMC6856675 DOI: 10.3389/fphys.2019.01391] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 10/25/2019] [Indexed: 01/23/2023] Open
Abstract
Background Neonatal asphyxia caused kidney injury and severe hypertension in a newborn. An unusually dilatated ascending aorta developed. Dialysis and pharmacological treatment led to partial recovery of the ascending aortic diameters. It was hypothesized that the aortic dilatation may be associated with aortic stiffening, peripheral resistance, and cardiovascular changes. Mathematical modeling was used to better understand the potential causes of the hypertension, and to confirm our clinical treatment within the confines of the model's capabilities. Methods The patient's systolic arterial blood pressure showed hypertension. Echocardiographic exams showed ascending aorta dilatation during hypertension, which partially normalized upon antihypertensive treatment. To explore the underlying mechanisms of the aortic dilatation and hypertension, an existing lumped parameter hemodynamics model was deployed. Hypertension was simulated using realistic literature informed parameter values. It was also simulated using large parameter perturbations to demonstrate effects. Simulations were designed to permit examination of causal mechanisms. The hypertension inducing effects of aortic stiffnesses, vascular resistances, and cardiac hypertrophy on blood flow and pressure were simulated. Sensitivity analysis was used to stratify causes. Results In agreement with our clinical diagnosis, the model showed that an increase of aortic stiffness followed by augmentation of peripheral resistance are the prime causes of realistic hypertension. Increased left ventricular elastance may also cause hypertension. Ascending aortic pressure and flow increased in the simultaneous presence of left ventricle hypertrophy and augmented small vessel resistance, which indicate a plausible condition for ascending aorta dilatation. In case of realistic hypertension, sensitivity analysis showed that the treatment of both the large vessel stiffness and small vessel resistance are more important in comparison to cardiac hypertrophy. Conclusion and Discussion Large vessel stiffness was found to be the prime factor in arterial hypertension, which confirmed the clinical treatment. Treatment of cardiac hypertrophy appears to provide significant benefit but may be secondary to treatment of large vessel stiffness. The quantitative grading of pathophysiological mechanisms provided by the modeling may contribute to treatment recommendations. The model was limited due to a lack of data suitable to permit model identification.
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Affiliation(s)
- Luis Altamirano-Diaz
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Children's Health Research Institute, London, ON, Canada.,Paediatric Cardiopulmonary Research Laboratory, LHSC, London, ON, Canada
| | | | - Baran Serajelahi
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Christopher W McIntyre
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
| | - Guido Filler
- Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Children's Health Research Institute, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
| | - Sanjay R Kharche
- Lawson Health Research Institute, London, ON, Canada.,Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada
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33
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Long-term hemodynamic mechanism of enhanced external counterpulsation in the treatment of coronary heart disease: a geometric multiscale simulation. Med Biol Eng Comput 2019; 57:2417-2433. [PMID: 31522354 DOI: 10.1007/s11517-019-02028-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 08/09/2019] [Indexed: 12/12/2022]
Abstract
Enhanced external counterpulsation (EECP) is a noninvasive treatment method for coronary artery atherosclerosis that acts on the vascular endothelial cells. The intracoronary hemodynamic parameters that influence long-term treatment effect are the fundamental factors for the inhibition of intimal hyperplasia, which cannot be measured in real time. In order to optimize the long-term treatment effect of coronary heart disease, it is necessary to establish a method for quantified calculation of intracoronary hemodynamic parameters during counterpulsation to research the long-term hemodynamic mechanism of EECP. A geometric multiscale model coupled by the zero-dimensional (0D) lumped parameter model and the three-dimensional (3D) model of narrow coronary artery was established for the simulation of intracoronary hemodynamic environment. The 3D model was used to calculate the hemodynamic parameters such as wall shear stress (WSS) and oscillatory shear index (OSI), while the 0D model was used to simulate the blood circulatory system. Sequential pressure was applied to calves, thighs, and buttocks module in 0D model with the consideration of vessel collapse. Hemodynamic performance was compared with clinical reports to verify the effectiveness of the method. There were significant increases of the diastolic blood pressure (DBP), coronary flow, and the area-averaged WSS during application of EECP, while OSI behind stenosis has some decrease. The waveforms of coronary flow has good similarity with the clinical measured waveforms, and the differences between calculated mean arterial pressures (MAPs) and clinical measurements were within 1%. The fundamental factor in the cure of coronary heart disease by EECP is the improvement of WSS and the decrease of OSI. Comparing with the clinical reports, the immediate hemodynamic changes demonstrate the effectiveness of model. Intracoronary hemodynamic parameters during EECP could be acquired and the method could be used to simulate the long-term treatment effect of EECP. Graphical abstract.
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34
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Duanmu Z, Chen W, Gao H, Yang X, Luo X, Hill NA. A One-Dimensional Hemodynamic Model of the Coronary Arterial Tree. Front Physiol 2019; 10:853. [PMID: 31338038 PMCID: PMC6629789 DOI: 10.3389/fphys.2019.00853] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 06/20/2019] [Indexed: 01/28/2023] Open
Abstract
One-dimensional (1D) hemodynamic models of arteries have increasingly been applied to coronary circulation. In this study, we have adopted flow and pressure profiles in Olufsen's 1D structured tree as coronary boundary conditions, with terminals coupled to the dynamic pressure feedback resulting from the intra-myocardial stress because of ventricular contraction. We model a trifurcation structure of the example coronary tree as two adjacent bifurcations. The estimated results of blood pressure and flow rate from our simulation agree well with the clinical measurements and published data. Furthermore, the 1D model enables us to use wave intensity analysis to simulate blood flow in the developed coronary model. Six characteristic waves are observed in both left and right coronary flows, though the waves' magnitudes differ from each other. We study the effects of arterial wall stiffness on coronary blood flow in the left circumflex artery (LCX). Different diseased cases indicate that distinct pathological reactions of the cardiovascular system can be better distinguished through Wave Intensity analysis, which shows agreement with clinical observations. Finally, the feedback pressure in terminal vessels and measurement deviation are also investigated by changing parameters in the LCX. We find that larger feedback pressure increases the backward wave and decreases the forward one. Although simplified, this 1D model provides new insight into coronary hemodynamics in healthy and diseased conditions. We believe that this approach offers reference resources for studies on coronary circulation disease diagnosis, treatment and simulation.
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Affiliation(s)
- Zheng Duanmu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Weiwei Chen
- Guangxi Key Laboratory of Regenerative Medicine, Research Centre for Regenerative Medicine, Guangxi Medical University, Guangxi, China
| | - Hao Gao
- School of Mathematics and Statistics, University of Glasgow, Glasgow, United Kingdom
| | - Xilan Yang
- Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, Glasgow, United Kingdom
| | - Nicholas A Hill
- School of Mathematics and Statistics, University of Glasgow, Glasgow, United Kingdom
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35
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Zhou S, Xu L, Hao L, Xiao H, Yao Y, Qi L, Yao Y. A review on low-dimensional physics-based models of systemic arteries: application to estimation of central aortic pressure. Biomed Eng Online 2019; 18:41. [PMID: 30940144 PMCID: PMC6446386 DOI: 10.1186/s12938-019-0660-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/26/2019] [Indexed: 12/16/2022] Open
Abstract
The physiological processes and mechanisms of an arterial system are complex and subtle. Physics-based models have been proven to be a very useful tool to simulate actual physiological behavior of the arteries. The current physics-based models include high-dimensional models (2D and 3D models) and low-dimensional models (0D, 1D and tube-load models). High-dimensional models can describe the local hemodynamic information of arteries in detail. With regard to an exact model of the whole arterial system, a high-dimensional model is computationally impracticable since the complex geometry, viscosity or elastic properties and complex vectorial output need to be provided. For low-dimensional models, the structure, centerline and viscosity or elastic properties only need to be provided. Therefore, low-dimensional modeling with lower computational costs might be a more applicable approach to represent hemodynamic properties of the entire arterial system and these three types of low-dimensional models have been extensively used in the study of cardiovascular dynamics. In recent decades, application of physics-based models to estimate central aortic pressure has attracted increasing interest. However, to our best knowledge, there has been few review paper about reconstruction of central aortic pressure using these physics-based models. In this paper, three types of low-dimensional physical models (0D, 1D and tube-load models) of systemic arteries are reviewed, the application of three types of models on estimation of central aortic pressure is taken as an example to discuss their advantages and disadvantages, and the proper choice of models for specific researches and applications are advised.
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Affiliation(s)
- Shuran Zhou
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, 110819 China
| | - Lisheng Xu
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, 110819 China
- Neusoft Research of Intelligent Healthcare Technology, Co. Ltd., Shenyang, 110167 China
| | - Liling Hao
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, 110819 China
| | - Hanguang Xiao
- Chongqing Key Laboratory of Modern Photoelectric Detection Technology and Instrument, School of Optoelectronic Information, Chongqing University of Technology, Chongqing, 400054 China
| | - Yang Yao
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, 110819 China
| | - Lin Qi
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, 110819 China
| | - Yudong Yao
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, 110819 China
- Neusoft Research of Intelligent Healthcare Technology, Co. Ltd., Shenyang, 110167 China
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