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Pegolotti L, Pfaller MR, Rubio NL, Ding K, Brugarolas Brufau R, Darve E, Marsden AL. Learning reduced-order models for cardiovascular simulations with graph neural networks. Comput Biol Med 2024; 168:107676. [PMID: 38039892 PMCID: PMC10886437 DOI: 10.1016/j.compbiomed.2023.107676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 10/23/2023] [Accepted: 11/06/2023] [Indexed: 12/03/2023]
Abstract
Reduced-order models based on physics are a popular choice in cardiovascular modeling due to their efficiency, but they may experience loss in accuracy when working with anatomies that contain numerous junctions or pathological conditions. We develop one-dimensional reduced-order models that simulate blood flow dynamics using a graph neural network trained on three-dimensional hemodynamic simulation data. Given the initial condition of the system, the network iteratively predicts the pressure and flow rate at the vessel centerline nodes. Our numerical results demonstrate the accuracy and generalizability of our method in physiological geometries comprising a variety of anatomies and boundary conditions. Our findings demonstrate that our approach can achieve errors below 3% for pressure and flow rate, provided there is adequate training data. As a result, our method exhibits superior performance compared to physics-based one-dimensional models while maintaining high efficiency at inference time.
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Affiliation(s)
- Luca Pegolotti
- Department of Pediatrics, Stanford University, United States of America; Institute for Computational and Mathematical Engineering, Stanford University, United States of America.
| | - Martin R Pfaller
- Department of Pediatrics, Stanford University, United States of America; Institute for Computational and Mathematical Engineering, Stanford University, United States of America
| | - Natalia L Rubio
- Department of Mechanical Engineering, Stanford University, United States of America
| | - Ke Ding
- Intel Corporation, United States of America
| | | | - Eric Darve
- Institute for Computational and Mathematical Engineering, Stanford University, United States of America; Department of Mechanical Engineering, Stanford University, United States of America
| | - Alison L Marsden
- Department of Pediatrics, Stanford University, United States of America; Institute for Computational and Mathematical Engineering, Stanford University, United States of America; Department of Mechanical Engineering, Stanford University, United States of America; Department of Bioengineering, Stanford University, United States of America
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2
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Schwarz EL, Pegolotti L, Pfaller MR, Marsden AL. Beyond CFD: Emerging methodologies for predictive simulation in cardiovascular health and disease. BIOPHYSICS REVIEWS 2023; 4:011301. [PMID: 36686891 PMCID: PMC9846834 DOI: 10.1063/5.0109400] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 12/12/2022] [Indexed: 01/15/2023]
Abstract
Physics-based computational models of the cardiovascular system are increasingly used to simulate hemodynamics, tissue mechanics, and physiology in evolving healthy and diseased states. While predictive models using computational fluid dynamics (CFD) originated primarily for use in surgical planning, their application now extends well beyond this purpose. In this review, we describe an increasingly wide range of modeling applications aimed at uncovering fundamental mechanisms of disease progression and development, performing model-guided design, and generating testable hypotheses to drive targeted experiments. Increasingly, models are incorporating multiple physical processes spanning a wide range of time and length scales in the heart and vasculature. With these expanded capabilities, clinical adoption of patient-specific modeling in congenital and acquired cardiovascular disease is also increasing, impacting clinical care and treatment decisions in complex congenital heart disease, coronary artery disease, vascular surgery, pulmonary artery disease, and medical device design. In support of these efforts, we discuss recent advances in modeling methodology, which are most impactful when driven by clinical needs. We describe pivotal recent developments in image processing, fluid-structure interaction, modeling under uncertainty, and reduced order modeling to enable simulations in clinically relevant timeframes. In all these areas, we argue that traditional CFD alone is insufficient to tackle increasingly complex clinical and biological problems across scales and systems. Rather, CFD should be coupled with appropriate multiscale biological, physical, and physiological models needed to produce comprehensive, impactful models of mechanobiological systems and complex clinical scenarios. With this perspective, we finally outline open problems and future challenges in the field.
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Affiliation(s)
- Erica L. Schwarz
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Luca Pegolotti
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Martin R. Pfaller
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Alison L. Marsden
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, California 94305, USA
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3
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Bhardwaj S, Craven BA, Sever JE, Costanzo F, Simon SD, Manning KB. Modeling Flow in an In Vitro Anatomical Cerebrovascular Model with Experimental Validation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523948. [PMID: 36711518 PMCID: PMC9882108 DOI: 10.1101/2023.01.13.523948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Acute ischemic stroke (AIS) is a leading cause of mortality that occurs when an embolus becomes lodged in the cerebral vasculature and obstructs blood flow in the brain. The severity of AIS is determined by the location and how extensively emboli become lodged, which are dictated in large part by the cerebral flow and the dynamics of embolus migration which are difficult to measure in vivo in AIS patients. Computational fluid dynamics (CFD) can be used to predict the patient-specific hemodynamics and embolus migration and lodging in the cerebral vasculature to better understand the underlying mechanics of AIS. To be relied upon, however, the computational simulations must be verified and validated. In this study, a realistic in vitro experimental model and a corresponding computational model of the cerebral vasculature are established that can be used to investigate flow and embolus migration and lodging in the brain. First, the in vitro anatomical model is described, including how the flow distribution in the model is tuned to match physiological measurements from the literature. Measurements of pressure and flow rate for both normal and stroke conditions were acquired and corresponding CFD simulations were performed and compared with the experiments to validate the flow predictions. Overall, the CFD simulations were in relatively close agreement with the experiments, to within ±7% of the mean experimental data with many of the CFD predictions within the uncertainty of the experimental measurement. This work provides an in vitro benchmark data set for flow in a realistic cerebrovascular model and is a first step towards validating a computational model of AIS.
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Affiliation(s)
- Saurabh Bhardwaj
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Brent A. Craven
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Jacob E. Sever
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
| | - Francesco Costanzo
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, USA
| | - Scott D. Simon
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Keefe B. Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, USA
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Bhardwaj S, Craven BA, Sever JE, Costanzo F, Simon SD, Manning KB. Modeling flow in an in vitro anatomical cerebrovascular model with experimental validation. FRONTIERS IN MEDICAL TECHNOLOGY 2023; 5:1130201. [PMID: 36908295 PMCID: PMC9996037 DOI: 10.3389/fmedt.2023.1130201] [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: 12/22/2022] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Acute ischemic stroke (AIS) is a leading cause of mortality that occurs when an embolus becomes lodged in the cerebral vasculature and obstructs blood flow in the brain. The severity of AIS is determined by the location and how extensively emboli become lodged, which are dictated in large part by the cerebral flow and the dynamics of embolus migration which are difficult to measure in vivo in AIS patients. Computational fluid dynamics (CFD) can be used to predict the patient-specific hemodynamics and embolus migration and lodging in the cerebral vasculature to better understand the underlying mechanics of AIS. To be relied upon, however, the computational simulations must be verified and validated. In this study, a realistic in vitro experimental model and a corresponding computational model of the cerebral vasculature are established that can be used to investigate flow and embolus migration and lodging in the brain. First, the in vitro anatomical model is described, including how the flow distribution in the model is tuned to match physiological measurements from the literature. Measurements of pressure and flow rate for both normal and stroke conditions were acquired and corresponding CFD simulations were performed and compared with the experiments to validate the flow predictions. Overall, the CFD simulations were in relatively close agreement with the experiments, to within ±7% of the mean experimental data with many of the CFD predictions within the uncertainty of the experimental measurement. This work provides an in vitro benchmark data set for flow in a realistic cerebrovascular model and is a first step towards validating a computational model of AIS.
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Affiliation(s)
- Saurabh Bhardwaj
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Brent A. Craven
- Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States
- Correspondence: Brent A. Craven Keefe B. Manning
| | - Jacob E. Sever
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
| | - Francesco Costanzo
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA, United States
| | - Scott D. Simon
- Department of Neurosurgery, Penn State Hershey Medical Center, Hershey, PA, United States
| | - Keefe B. Manning
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, United States
- Correspondence: Brent A. Craven Keefe B. Manning
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Birla AK, Brimmer S, Short WD, Olutoye OO, Shar JA, Lalwani S, Sucosky P, Parthiban A, Keswani SG, Caldarone CA, Birla RK. Current state of the art in hypoplastic left heart syndrome. Front Cardiovasc Med 2022; 9:878266. [PMID: 36386362 PMCID: PMC9651920 DOI: 10.3389/fcvm.2022.878266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/30/2022] [Indexed: 11/29/2022] Open
Abstract
Hypoplastic left heart syndrome (HLHS) is a complex congenital heart condition in which a neonate is born with an underdeveloped left ventricle and associated structures. Without palliative interventions, HLHS is fatal. Treatment typically includes medical management at the time of birth to maintain patency of the ductus arteriosus, followed by three palliative procedures: most commonly the Norwood procedure, bidirectional cavopulmonary shunt, and Fontan procedures. With recent advances in surgical management of HLHS patients, high survival rates are now obtained at tertiary treatment centers, though adverse neurodevelopmental outcomes remain a clinical challenge. While surgical management remains the standard of care for HLHS patients, innovative treatment strategies continue to be developing. Important for the development of new strategies for HLHS patients is an understanding of the genetic basis of this condition. Another investigational strategy being developed for HLHS patients is the injection of stem cells within the myocardium of the right ventricle. Recent innovations in tissue engineering and regenerative medicine promise to provide important tools to both understand the underlying basis of HLHS as well as provide new therapeutic strategies. In this review article, we provide an overview of HLHS, starting with a historical description and progressing through a discussion of the genetics, surgical management, post-surgical outcomes, stem cell therapy, hemodynamics and tissue engineering approaches.
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Affiliation(s)
- Aditya K. Birla
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Center for Congenital Cardiac Research, Texas Children's Hospital, Houston, TX, United States
| | - Sunita Brimmer
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Center for Congenital Cardiac Research, Texas Children's Hospital, Houston, TX, United States
- Division of Congenital Heart Surgery, Texas Children's Hospital, Houston, TX, United States
| | - Walker D. Short
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Department of Surgery, Baylor College of Medicine, Houston, TX, United States
- Division of Pediatric Surgery, Department of Surgery, Texas Children's Hospital, Houston, TX, United States
| | - Oluyinka O. Olutoye
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Department of Surgery, Baylor College of Medicine, Houston, TX, United States
- Division of Pediatric Surgery, Department of Surgery, Texas Children's Hospital, Houston, TX, United States
| | - Jason A. Shar
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, United States
| | - Suriya Lalwani
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Center for Congenital Cardiac Research, Texas Children's Hospital, Houston, TX, United States
| | - Philippe Sucosky
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, United States
| | - Anitha Parthiban
- Department of Surgery, Baylor College of Medicine, Houston, TX, United States
- Division of Pediatric Surgery, Department of Surgery, Texas Children's Hospital, Houston, TX, United States
- Division of Pediatric Cardiology, Texas Children's Hospital, Houston, TX, United States
| | - Sundeep G. Keswani
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Center for Congenital Cardiac Research, Texas Children's Hospital, Houston, TX, United States
- Department of Surgery, Baylor College of Medicine, Houston, TX, United States
- Division of Pediatric Surgery, Department of Surgery, Texas Children's Hospital, Houston, TX, United States
| | - Christopher A. Caldarone
- Center for Congenital Cardiac Research, Texas Children's Hospital, Houston, TX, United States
- Division of Congenital Heart Surgery, Texas Children's Hospital, Houston, TX, United States
- Department of Surgery, Baylor College of Medicine, Houston, TX, United States
- Division of Pediatric Surgery, Department of Surgery, Texas Children's Hospital, Houston, TX, United States
| | - Ravi K. Birla
- Laboratory for Regenerative Tissue Repair, Texas Children's Hospital, Houston, TX, United States
- Center for Congenital Cardiac Research, Texas Children's Hospital, Houston, TX, United States
- Division of Congenital Heart Surgery, Texas Children's Hospital, Houston, TX, United States
- Department of Surgery, Baylor College of Medicine, Houston, TX, United States
- Division of Pediatric Surgery, Department of Surgery, Texas Children's Hospital, Houston, TX, United States
- *Correspondence: Ravi K. Birla
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Pfaller MR, Pham J, Verma A, Pegolotti L, Wilson NM, Parker DW, Yang W, Marsden AL. Automated generation of 0D and 1D reduced-order models of patient-specific blood flow. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3639. [PMID: 35875875 PMCID: PMC9561079 DOI: 10.1002/cnm.3639] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 05/24/2022] [Accepted: 07/19/2022] [Indexed: 06/13/2023]
Abstract
Three-dimensional (3D) cardiovascular fluid dynamics simulations typically require hours to days of computing time on a high-performance computing cluster. One-dimensional (1D) and lumped-parameter zero-dimensional (0D) models show great promise for accurately predicting blood bulk flow and pressure waveforms with only a fraction of the cost. They can also accelerate uncertainty quantification, optimization, and design parameterization studies. Despite several prior studies generating 1D and 0D models and comparing them to 3D solutions, these were typically limited to either 1D or 0D and a singular category of vascular anatomies. This work proposes a fully automated and openly available framework to generate and simulate 1D and 0D models from 3D patient-specific geometries, automatically detecting vessel junctions and stenosis segments. Our only input is the 3D geometry; we do not use any prior knowledge from 3D simulations. All computational tools presented in this work are implemented in the open-source software platform SimVascular. We demonstrate the reduced-order approximation quality against rigid-wall 3D solutions in a comprehensive comparison with N = 72 publicly available models from various anatomies, vessel types, and disease conditions. Relative average approximation errors of flows and pressures typically ranged from 1% to 10% for both 1D and 0D models, measured at the outlets of terminal vessel branches. In general, 0D model errors were only slightly higher than 1D model errors despite requiring only a third of the 1D runtime. Automatically generated ROMs can significantly speed up model development and shift the computational load from high-performance machines to personal computers.
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Affiliation(s)
- Martin R. Pfaller
- Pediatric Cardiology, Stanford University, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, CA, USA
- Cardiovascular Institute, Stanford University, CA, USA
| | - Jonathan Pham
- Mechanical Engineering, Stanford University, CA, USA
| | | | - Luca Pegolotti
- Pediatric Cardiology, Stanford University, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, CA, USA
| | | | | | | | - Alison L. Marsden
- Pediatric Cardiology, Stanford University, CA, USA
- Institute for Computational and Mathematical Engineering, Stanford University, CA, USA
- Cardiovascular Institute, Stanford University, CA, USA
- Bioengineering, Stanford University, CA, USA
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Chi Z, Beile L, Deyu L, Yubo F. Application of multiscale coupling models in the numerical study of circulation system. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2022. [DOI: 10.1016/j.medntd.2022.100117] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Wang L, Ansari S, Cai Y, McCracken B, Tiba MH, Ward K, Najarian K, Oldham K. Tracking Peripheral Artery Motion and Vascular Resistance with a Multi-Modal Wearable Sensor Under Pressure Perturbations. J Biomech Eng 2022; 144:1133339. [PMID: 35079769 DOI: 10.1115/1.4053399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Indexed: 11/08/2022]
Abstract
Peripheral artery status is a key physiological indicator of the body's cardiovascular response to both acute and chronic medical conditions. In this paper, peripheral artery behavior is tracked non-invasively by combining a photo plethysmograph (PPG) sensor and a piezoelectric (polyvinylidene difluoride, PVDF) sensor, while applying an outside pressure-varying cuff. A simple mechanical model for the local artery and tissue captures time- and pressure-dependent features present in the PPG and PVDF signals with respect to applied cuff pressure, during maneuvers applied to multiple swine subjects to perturb blood pressure and vascular resistance. These behaviors provide insight into feasibility and robustness of cardiovascular property identification by multi-modal non-invasive wearable sensing. This is found to help refine non-invasive blood pressure measurements and estimation of systemic vascular resistance (SVR) and blood pressure (BP) using selected features of sensor amplitude versus applied cuff pressure.
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Affiliation(s)
- Lu Wang
- University of Michigan, Ann Arbor, Michigan, USA
| | | | - Yingjie Cai
- University of Michigan, Ann Arbor, Michigan, USA
| | | | | | - Kevin Ward
- University of Michigan, Ann Arbor, Michigan, USA
| | | | - Kenn Oldham
- University of Michigan, Ann Arbor, Michigan, USA
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Ho H, Ran T, Ji X. Secondhand Smoking and Sudden Infant Death Syndrome: How can in Silico Pharmacokinetics and Circulation Models Contribute? Front Bioeng Biotechnol 2022; 9:820404. [PMID: 35111743 PMCID: PMC8802112 DOI: 10.3389/fbioe.2021.820404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 12/29/2021] [Indexed: 11/28/2022] Open
Affiliation(s)
- Harvey Ho
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- *Correspondence: Harvey Ho, ; Xiaojuan Ji,
| | - Tingting Ran
- Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaojuan Ji
- Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
- *Correspondence: Harvey Ho, ; Xiaojuan Ji,
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Rigatelli G, Chiastra C, Pennati G, Dubini G, Migliavacca F, Zuin M. Applications of computational fluid dynamics to congenital heart diseases: a practical review for cardiovascular professionals. Expert Rev Cardiovasc Ther 2021; 19:907-916. [PMID: 34704881 DOI: 10.1080/14779072.2021.1999229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The increased survival rate of patients with congenital heart disease (CHD) has made it likely that 70%-95% of infants with CHDs surviving into adulthood often require careful follow-up and (repeat) interventions. Patients with CHDs often have abnormal blood flow patterns, due to both primary cardiac defect and the consequent surgical or endovascular repair. AREA COVERED Computational fluid dynamics (CFD) alone or coupled with advanced imaging tools can assess blood flow patterns of CHDs to both understand their pathophysiology and anticipate the results of surgical or interventional repair. EXPERT OPINION CFD is a mathematical technique that quantifies and describes the characteristics of fluid flow using the laws of physics. Through dedicated software based on virtual reconstruction and simulation and patients' real data coming from computed tomography, magnetic resonance imaging, and 3/4 D-ultrasound, reconstruction of models of circulation of most CHD can be accomplished. CFD can provide insights about the pathophysiology of coronary artery anomalies, interatrial shunts, coarctation of the aorta and aortic bicuspid valve, tetralogy of Fallot and univentricular heart, with the capability in some cases of simulating different types of surgical or interventional repair and tailoring the treatment on the basis of these findings.
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Affiliation(s)
- Gianluca Rigatelli
- Cardiovascular Diagnosis and Endoluminal Interventions Unit, Rovigo General Hospital, Rovigo, Italy
| | - Claudio Chiastra
- PoliToBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Giancarlo Pennati
- Laboratory of Biological Structure Mechanics (Labs), Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Milan, Italy
| | - Gabriele Dubini
- Laboratory of Biological Structure Mechanics (Labs), Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Milan, Italy
| | - Francesco Migliavacca
- Laboratory of Biological Structure Mechanics (Labs), Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Milan, Italy
| | - Marco Zuin
- Section of Internal and Cardiopulmonary Medicine, University of Ferrara, Ferrara, Italy
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Investigations into the Potential of Using Open Source CFD to Analyze the Differences in Hemodynamic Parameters for Aortic Dissections (Healthy versus Stanford Type A and B). Ann Vasc Surg 2021; 79:310-323. [PMID: 34648855 DOI: 10.1016/j.avsg.2021.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/11/2021] [Accepted: 08/14/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The objective of this study was to develop a method to evaluate the effects of an aortic dissection on hemodynamic parameters by conducting a comparison with that of a healthy (nondissected) aorta. Open-source software will be implemented, no proprietary software/application will be used to ensure accessorily and repeatability, in all the data analysis and processing. Computed tomography (CT) images of aortic dissection are used for the model geometry segmentation. Boundary conditions from literature are implemented to computational fluid dynamics (CFD) to analyze the hemodynamic parameters. METHODS A numerical simulation model was created by obtaining accurate 3-dimensional geometries of aortae from CT images. In this study, CT images of 8 cases of aortic dissection (Stanford type-A and type-B) and 3 cases of healthy aortae are used for the actual aorta model geometry segmentation. These models were exported into an open-source CFD software, OpenFOAM, where a simplified pulsating flow was simulated by controlling the flow pressure. Ten cycles of the pulsatile flow (0.50 sec/cycle) conditions, totaling 5 sec, were calculated. RESULTS The pressure distribution, wall shear stress (WSS) and flow velocity streamlines within the aorta and the false lumen were calculated and visualized. It was found that the flow velocity and WSS had a high correlation in high WSS areas of the intermittent layer between the true and false lumen. Most of the Stanford type-A dissections in the study showed high WSS, over 38 Pa, at the systole phase. This indicates that the arterial walls in type-A dissections are more likely to be damaged with pulsatile flow. CONCLUSIONS Using CFD to estimate localized high WSS areas may help in deciding to treat a type-A or B dissection with a stent graft to prevent a potential rupture.
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12
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Li Z, Jiang W, Diao J, Chen C, Xu K, Fan H, Yan F. Segmentary strategy in modeling of cardiovascular system with blood supply to regional skin. Biocybern Biomed Eng 2021. [DOI: 10.1016/j.bbe.2021.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Saw SN, Dai Y, Yap CH. A Review of Biomechanics Analysis of the Umbilical-Placenta System With Regards to Diseases. Front Physiol 2021; 12:587635. [PMID: 34475826 PMCID: PMC8406807 DOI: 10.3389/fphys.2021.587635] [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: 07/27/2020] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Placenta is an important organ that is crucial for both fetal and maternal health. Abnormalities of the placenta, such as during intrauterine growth restriction (IUGR) and pre-eclampsia (PE) are common, and an improved understanding of these diseases is needed to improve medical care. Biomechanics analysis of the placenta is an under-explored area of investigation, which has demonstrated usefulness in contributing to our understanding of the placenta physiology. In this review, we introduce fundamental biomechanics concepts and discuss the findings of biomechanical analysis of the placenta and umbilical cord, including both tissue biomechanics and biofluid mechanics. The biomechanics of placenta ultrasound elastography and its potential in improving clinical detection of placenta diseases are also discussed. Finally, potential future work is listed.
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Affiliation(s)
- Shier Nee Saw
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Yichen Dai
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Choon Hwai Yap
- Department of Bioengineering, Imperial College London, London, United Kingdom
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14
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Schwarz EL, Kelly JM, Blum KM, Hor KN, Yates AR, Zbinden JC, Verma A, Lindsey SE, Ramachandra AB, Szafron JM, Humphrey JD, Shin'oka T, Marsden AL, Breuer CK. Hemodynamic performance of tissue-engineered vascular grafts in Fontan patients. NPJ Regen Med 2021; 6:38. [PMID: 34294733 PMCID: PMC8298568 DOI: 10.1038/s41536-021-00148-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 06/11/2021] [Indexed: 02/06/2023] Open
Abstract
In the field of congenital heart surgery, tissue-engineered vascular grafts (TEVGs) are a promising alternative to traditionally used synthetic grafts. Our group has pioneered the use of TEVGs as a conduit between the inferior vena cava and the pulmonary arteries in the Fontan operation. The natural history of graft remodeling and its effect on hemodynamic performance has not been well characterized. In this study, we provide a detailed analysis of the first U.S. clinical trial evaluating TEVGs in the treatment of congenital heart disease. We show two distinct phases of graft remodeling: an early phase distinguished by rapid changes in graft geometry and a second phase of sustained growth and decreased graft stiffness. Using clinically informed and patient-specific computational fluid dynamics (CFD) simulations, we demonstrate how changes to TEVG geometry, thickness, and stiffness affect patient hemodynamics. We show that metrics of patient hemodynamics remain within normal ranges despite clinically observed levels of graft narrowing. These insights strengthen the continued clinical evaluation of this technology while supporting recent indications that reversible graft narrowing can be well tolerated, thus suggesting caution before intervening clinically.
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Affiliation(s)
- Erica L Schwarz
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
| | - John M Kelly
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Kevin M Blum
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Kan N Hor
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Andrew R Yates
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Jacob C Zbinden
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Aekaansh Verma
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Stephanie E Lindsey
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | | | - Jason M Szafron
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Toshiharu Shin'oka
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Cardiothoracic Surgery, Nationwide Children's Hospital, Columbus, OH, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | - Christopher K Breuer
- Center for Regenerative Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Surgery, Nationwide Children's Hospital, Columbus, OH, USA
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15
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Ninos G, Bartzis V, Merlemis N, Sarris IE. Uncertainty quantification implementations in human hemodynamic flows. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 203:106021. [PMID: 33721602 DOI: 10.1016/j.cmpb.2021.106021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Human hemodynamic modeling is usually influenced by uncertainties occurring from a considerable unavailability of information linked to the boundary conditions and the physical properties used in the numerical models. Calculating the effect of these uncertainties on the numerical findings along the cardiovascular system is a demanding process due to the complexity of the morphology of the body and the area dynamics. To cope with all these difficulties, Uncertainty Quantification (UQ) methods seem to be an ideal tool. RESULTS This study focuses on analyzing and summarizing some of the recent research efforts and directions of implementing UQ in human hemodynamic flows by analyzing 139 research papers. Initially, the suitability of applying this approach is analyzed and demonstrated. Then, an overview of the most significant research work in various fields of biomedical hemodynamic engineering is presented. Finally, it is attempted to identify any possible forthcoming directions for research and methodological progress of UQ in biomedical sciences. CONCLUSION This review concludes that by finding the best statistical methods and parameters to represent the propagated uncertainties, while achieving a good interpretation of the interaction between input-output, is crucial for implementing UQ in biomedical sciences.
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Affiliation(s)
- G Ninos
- Department of Biomedical Sciences, University of West Attica, 12243, Athens, Greece; Department of Mechanical Engineering, University of West Attica, 12244, Athens, Greece.
| | - V Bartzis
- Department of Food Science & Technology, University of West Attica, 12243, Athens, Greece
| | - N Merlemis
- Deptartment of Surveying and Geoinformatics Engineering, University of West Attica, 12243 Athens, Greece
| | - I E Sarris
- Department of Mechanical Engineering, University of West Attica, 12244, Athens, Greece
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16
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Edlin J, Youssefi P, Bilkhu R, Figueroa CA, Morgan R, Nowell J, Jahangiri M. Haemodynamic assessment of bicuspid aortic valve aortopathy: a systematic review of the current literature. Eur J Cardiothorac Surg 2020; 55:610-617. [PMID: 30239633 DOI: 10.1093/ejcts/ezy312] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/09/2018] [Accepted: 08/15/2018] [Indexed: 11/12/2022] Open
Abstract
Both genetic and haemodynamic theories explain the aetiology, progression and optimal management of bicuspid aortic valve aortopathy. In recent years, the haemodynamic theory has been explored with the help of magnetic resonance imaging and computational fluid dynamics. The objective of this review was to summarize the findings of these investigations with focus on the blood flow pattern and associated variables, including flow eccentricity, helicity, flow displacement, cusp opening angle, systolic flow angle, wall shear stress (WSS) and oscillatory shear index. A structured literature review was performed from January 1990 to January 2018 and revealed the following 3 main findings: (i) the bicuspid aortic valve is associated with flow eccentricity and helicity in the ascending aorta compared to healthy and diseased tricuspid aortic valve, (ii) flow displacement is easier to obtain than WSS and has been shown to correlate with valve morphology and type of aortopathy and (iii) the stenotic bicuspid aortic valve is associated with elevated WSS along the greater curvature of the ascending aorta, where aortic dilatation and aortic wall thinning are commonly found. We conclude that new haemodynamic variables should complement ascending aorta diameter as an indicator for disease progression and the type and timing of intervention. WSS describes the force that blood flow exerts on the vessel wall as a function of viscosity and geometry of the vessel, making it a potentially more reliable marker of disease progression.
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Affiliation(s)
- Joy Edlin
- Department of Cardiothoracic Surgery, St George's Hospital, London, UK
| | - Pouya Youssefi
- Department of Cardiothoracic Surgery, St George's Hospital, London, UK
| | - Rajdeep Bilkhu
- Department of Cardiothoracic Surgery, St George's Hospital, London, UK
| | - Carlos Alberto Figueroa
- Department of Biomedical Engineering, King's College London, London, UK.,Department of Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Robert Morgan
- Department of Radiology, St George's Hospital, London, UK
| | - Justin Nowell
- Department of Cardiothoracic Surgery, St George's Hospital, London, UK
| | - Marjan Jahangiri
- Department of Cardiothoracic Surgery, St George's Hospital, London, UK
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17
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Gerrah R, Haller SJ. Computational fluid dynamics: a primer for congenital heart disease clinicians. Asian Cardiovasc Thorac Ann 2020; 28:520-532. [PMID: 32878458 DOI: 10.1177/0218492320957163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Computational fluid dynamics has become an important tool for studying blood flow dynamics. As an in-silico collection of methods, computational fluid dynamics is noninvasive and provides numerical values for the most important parameters of blood flow, such as velocity and pressure that are crucial in hemodynamic studies. In this primer, we briefly explain the basic theory and workflow of the two most commonly applied computational fluid dynamics techniques used in the congenital heart disease literature: the finite element method and the finite volume method. We define important terminology and include specific examples of how using these methods can answer important clinical questions in congenital cardiac surgery planning and perioperative patient management.
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Affiliation(s)
- Rabin Gerrah
- Stanford University, Samaritan Cardiovascular Surgery, Corvallis, OR, USA
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18
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Fleeter CM, Geraci G, Schiavazzi DE, Kahn AM, Marsden AL. Multilevel and multifidelity uncertainty quantification for cardiovascular hemodynamics. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2020; 365:113030. [PMID: 32336811 PMCID: PMC7182133 DOI: 10.1016/j.cma.2020.113030] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Standard approaches for uncertainty quantification in cardiovascular modeling pose challenges due to the large number of uncertain inputs and the significant computational cost of realistic three-dimensional simulations. We propose an efficient uncertainty quantification framework utilizing a multilevel multifidelity Monte Carlo (MLMF) estimator to improve the accuracy of hemodynamic quantities of interest while maintaining reasonable computational cost. This is achieved by leveraging three cardiovascular model fidelities, each with varying spatial resolution to rigorously quantify the variability in hemodynamic outputs. We employ two low-fidelity models (zero- and one-dimensional) to construct several different estimators. Our goal is to investigate and compare the efficiency of estimators built from combinations of these two low-fidelity model alternatives and our high-fidelity three-dimensional models. We demonstrate this framework on healthy and diseased models of aortic and coronary anatomy, including uncertainties in material property and boundary condition parameters. Our goal is to demonstrate that for this application it is possible to accelerate the convergence of the estimators by utilizing a MLMF paradigm. Therefore, we compare our approach to single fidelity Monte Carlo estimators and to a multilevel Monte Carlo approach based only on three-dimensional simulations, but leveraging multiple spatial resolutions. We demonstrate significant, on the order of 10 to 100 times, reduction in total computational cost with the MLMF estimators. We also examine the differing properties of the MLMF estimators in healthy versus diseased models, as well as global versus local quantities of interest. As expected, global quantities such as outlet pressure and flow show larger reductions than local quantities, such as those relating to wall shear stress, as the latter rely more heavily on the highest fidelity model evaluations. Similarly, healthy models show larger reductions than diseased models. In all cases, our workflow coupling Dakota's MLMF estimators with the SimVascular cardiovascular modeling framework makes uncertainty quantification feasible for constrained computational budgets.
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Affiliation(s)
- Casey M. Fleeter
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
| | - Gianluca Geraci
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, USA
| | - Daniele E. Schiavazzi
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, USA
| | - Andrew M. Kahn
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Alison L. Marsden
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, CA, USA
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19
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Attaran SH, Niroomand-Oscuii H, Ghalichi F. Local hemodynamic analysis of the C-Pulse Device by 3D fluid-structure interaction simulation. Future Cardiol 2020; 16:297-308. [PMID: 32228240 DOI: 10.2217/fca-2019-0004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background: C-Pulse is a new, nonblood contacting device based on the concept of counter-pulsation that is designed for long-term implantation. However, there is a lack of comprehensive investigation of the pressure and velocity fields under the action of C-Pulse. Aim: In this paper, we aim to conduct a numerical simulation of the underlying mechanism of the device in order to analyze its performance and related undesirable issues. Materials & methods: A 3D finite element model is utilized to simulate the mechanism of the blood pumping. Results & conclusion: The simulation well reproduced the essential characteristics of the C-Pulse. Preliminary results were in a reasonable range while a couple of irregular flow patterns were identified.
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Affiliation(s)
| | | | - Farzan Ghalichi
- Department of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
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20
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3D Simulation Analysis of Central Shunt in Patient-Specific Hemodynamics: Effects of Varying Degree of Pulmonary Artery Stenosis and Shunt Diameters. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2020; 2020:4720908. [PMID: 32148557 PMCID: PMC7042498 DOI: 10.1155/2020/4720908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/16/2020] [Indexed: 12/27/2022]
Abstract
The objective of this study was to compare the effects of different shunt diameters and pulmonary artery (PA) stenosis grades on the hemodynamics of central shunts to determine an optimal surgical plan and improve the long-term outcomes of the operation. A 3D anatomical model was reconstructed based on the patient's clinical CT data. 3D computational fluid dynamics models were built with varying degrees of stenosis (the stenosis ratio α was represented by the ratio of blood flow through the main pulmonary artery to cardiac output, ranging from 0 to 30%; the smaller the value of α, the more severe the pulmonary artery stenosis) and varying shunt diameters (3, 3.5, 4, 4.5, and 5 mm). Our results show that the asymmetry of pulmonary artery flow increased with increasing shunt diameter and α, which will be more conducive to the development of the left pulmonary artery. Additionally, the pulmonary-to-systemic flow ratio (QP/QS) increases with the shunt diameter and α, and all the values exceed 1. When the shunt diameter is 3 mm and α = 0%, QP/QS reaches the minimum value of 1.01, and the oxygen delivery reaches the maximum value of 205.19 ml/min. However, increasing shunt diameter and α is beneficial to reduced power loss and smoother PA flow. In short, for patients with severe PA stenosis (α is small), a larger-diameter shunt may be preferred. Conversely, when the degree of PA stenosis is moderate, a smaller shunt diameter can be considered.
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21
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Virtual Fitting and Hemodynamic Simulation of the EVAHEART 2 Left Ventricular Assist Device and Double-Cuff Tipless Inflow Cannula. ASAIO J 2019; 65:698-706. [DOI: 10.1097/mat.0000000000000867] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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22
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Thomas VS, Lai V, Amini R. A computational multi-scale approach to investigate mechanically-induced changes in tricuspid valve anterior leaflet microstructure. Acta Biomater 2019; 94:524-535. [PMID: 31229629 DOI: 10.1016/j.actbio.2019.05.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 05/10/2019] [Accepted: 05/16/2019] [Indexed: 12/12/2022]
Abstract
The tricuspid valve is an atrioventricular valve that prevents blood backflow from the right ventricle into the right atrium during ventricular contractions. It is important to study mechanically induced microstructural alterations in the tricuspid valve leaflets, as this aids both in understanding valvular diseases and in the development of new engineered tissue replacements. The structure and composition of the extracellular matrix (ECM) fiber networks are closely tied to an overall biomechanical function of the tricuspid valve. In this study, we conducted experiments and implemented a multiscale modeling approach to predict ECM microstructural changes to tissue-level mechanical responses in a controlled loading environment. In particular, we characterized a sample of a porcine anterior leaflet at a macroscale using a biaxial mechanical testing method. We then generated a three-dimensional finite element model, to which computational representations of corresponding fiber networks were incorporated based on properties of the microstructural architecture obtained from small angle light scattering. Using five different biaxial boundary conditions, we performed iterative simulations to obtain model parameters with an overall R2 value of 0.93. We observed that mechanical loading could markedly alter the underlying ECM architecture. For example, a relatively isotropic fiber network (with an anisotropy index value α of 28%) became noticeably more anisotropic (with an α of 40%) when it underwent mechanical loading. We also observed that the mechanical strain was distributed in a different manner at the ECM/fiber level as compared to the tissue level. The approach presented in this study has the potential to be implemented in pathophysiologically altered biomechanical and structural conditions and to bring insights into the mechanobiology of the tricuspid valve. STATEMENT OF SIGNIFICANCE: Quantifying abnormal cellar/ECM-level deformation of tricuspid valve leaflets subjected to a modified loading environment is of great importance, as it is believed to be linked to valvular remodeling responses. For example, developing surgical procedures or engineered tissue replacements that maintain/mimic ECM-level mechanical homeostasis could lead to more durable outcomes. To quantify leaflet deformation, we built a multiscale framework encompassing the contributions of disorganized ECM components and organized fibers, which can predict the behavior of the tricuspid valve leaflets under physiological loading conditions both at the tissue level and at the ECM level. In addition to future in-depth studies of tricuspid valve pathologies, our model can be used to characterize tissues in other valves of the heart.
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23
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ZHANG XIAOYAN, WU DANDAN, MAO BOYAN, LI BAO, YANG HAISHENG, LIU YOUJUN. HEMODYNAMIC MECHANISM OF “BLOOD STOLEN” PHENOMENON IN CORONARY ARTERY ANEURYSM. J MECH MED BIOL 2019. [DOI: 10.1142/s0219519419500337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Blood is lost in coronary artery aneurysm (CAA), leading to a decrease in downstream blood flow, called the “blood stolen” phenomenon. In the clinic, the “blood stolen” phenomenon may lead to dilated myocardial ischemia. The mechanism of dilated myocardial ischemia, which is different from that of stenotic myocardial ischemia, has not yet been studied. The purpose of this study is to reveal the mechanism of dilated myocardial ischemia induced by the “blood stolen” phenomenon. In this paper, a lumped parameter model of the cardiovascular system with a CAA was established, a parallel structure was used to represent CAA. Three different sized CAAs were simulated, and their upstream and downstream blood flows were observed. The results showed that small and medium CAAs lead to 5.21% and 9.57% reductions, respectively, in the downstream flow. Giant CAAs lead to a more than 14% reduction in the downstream flow, while the upstream blood flow showed diastolic backward flow. The results of this numerical simulation are consistent with the clinical description. When blood flows into CAAs, it cannot flow downstream normally, and due to the wall elasticity of the CAA, there is diastolic backward flow, eventually leading to dilated myocardial ischemia. With expansion of the CAA, the “blood stolen” phenomenon will be more severe.
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Affiliation(s)
- XIAOYAN ZHANG
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - DANDAN WU
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - BOYAN MAO
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - BAO LI
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - HAISHENG YANG
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - YOUJUN LIU
- College of Life Science and Bio-Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
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24
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Gundelwein L, Miró J, Gonzalez Barlatay F, Lapierre C, Rohr K, Duong L. Personalized stent design for congenital heart defects using pulsatile blood flow simulations. J Biomech 2018; 81:68-75. [PMID: 30274737 DOI: 10.1016/j.jbiomech.2018.09.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 05/29/2018] [Accepted: 09/13/2018] [Indexed: 11/26/2022]
Abstract
Stent size selection and placement are among the most challenging tasks in the treatment of pulmonary artery stenosis in congenital heart defects (CHD). Patient-specific 3D model from CT or MR improves the understanding of the patient's anatomy and information about the hemodynamics aid in patient risk assessment and treatment planning. This work presents a new approach for personalized stent design in pulmonary artery interventions combining personalized patient geometry and hemodynamic simulations. First, the stent position is initialized using a geometric approach. Second, the stent and artery expansion, including the foreshortening behavior of the stent is simulated. Two stent designs are considered, a regular stent and a Y-stent for bifurcations. Computational fluid dynamics (CFD) simulations of the blood flow in the initial and expanded artery models are performed using patient-specific boundary conditions in form of a pulsatile inflow waveform, 3-element Windkessel outflow conditions, and deformable vessel walls. The simulations have been applied to 16 patient cases with a large variability of anatomies. Finally, the simulations have been clinically validated using retrospective imaging from angiography and pressure measurements. The simulated pressure, volume flow and flow velocity values were on the same order of magnitude as the reference values obtained from clinical measurements, and the simulated stent placement showed a positive impact on the hemodynamic values. Simulation of geometric changes combined with CFD simulations offers the possibility to optimize stent type, size, and position by evaluating different configurations before the intervention, and eventually allow to test customized stent geometries and new deployment techniques in CHD.
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Affiliation(s)
- L Gundelwein
- University of Heidelberg, BioQuant, IPMB, and DKFZ Heidelberg, Biomedical Computer Vision Group, 69120 Heidelberg, Germany; École de technologie supérieure, 1100 Notre-Dame St W, Montreal, QC H3C 1K3, Canada
| | - J Miró
- Centre hospitalier universitaire Sainte-Justine, 3175 Chemin de la Côte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada
| | - F Gonzalez Barlatay
- Centre hospitalier universitaire Sainte-Justine, 3175 Chemin de la Côte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada
| | - C Lapierre
- Centre hospitalier universitaire Sainte-Justine, 3175 Chemin de la Côte-Sainte-Catherine, Montreal, QC H3T 1C5, Canada
| | - K Rohr
- University of Heidelberg, BioQuant, IPMB, and DKFZ Heidelberg, Biomedical Computer Vision Group, 69120 Heidelberg, Germany
| | - L Duong
- École de technologie supérieure, 1100 Notre-Dame St W, Montreal, QC H3C 1K3, Canada.
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25
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Youssefi P, Gomez A, Arthurs C, Sharma R, Jahangiri M, Alberto Figueroa C. Impact of Patient-Specific Inflow Velocity Profile on Hemodynamics of the Thoracic Aorta. J Biomech Eng 2018; 140:2654063. [PMID: 28890987 DOI: 10.1115/1.4037857] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Indexed: 11/08/2022]
Abstract
Computational fluid dynamics (CFD) provides a noninvasive method to functionally assess aortic hemodynamics. The thoracic aorta has an anatomically complex inlet comprising of the aortic valve and root, which is highly prone to different morphologies and pathologies. We investigated the effect of using patient-specific (PS) inflow velocity profiles compared to idealized profiles based on the patient's flow waveform. A healthy 31 yo with a normally functioning tricuspid aortic valve (subject A), and a 52 yo with a bicuspid aortic valve (BAV), aortic valvular stenosis, and dilated ascending aorta (subject B) were studied. Subjects underwent MR angiography to image and reconstruct three-dimensional (3D) geometric models of the thoracic aorta. Flow-magnetic resonance imaging (MRI) was acquired above the aortic valve and used to extract the patient-specific velocity profiles. Subject B's eccentric asymmetrical inflow profile led to highly complex velocity patterns, which were not replicated by the idealized velocity profiles. Despite having identical flow rates, the idealized inflow profiles displayed significantly different peak and radial velocities. Subject A's results showed some similarity between PS and parabolic inflow profiles; however, other parameters such as Flowasymmetry were significantly different. Idealized inflow velocity profiles significantly alter velocity patterns and produce inaccurate hemodynamic assessments in the thoracic aorta. The complex structure of the aortic valve and its predisposition to pathological change means the inflow into the thoracic aorta can be highly variable. CFD analysis of the thoracic aorta needs to utilize fully PS inflow boundary conditions in order to produce truly meaningful results.
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Affiliation(s)
- Pouya Youssefi
- Department of Cardiothoracic Surgery, St. George's Hospital, London SW17 0QT, UK.,Department of Biomedical Engineering, King's College London, London SE1 7EH, UK e-mail:
| | - Alberto Gomez
- Department of Biomedical Engineering, King's College London, London SE1 7EH, UK e-mail:
| | - Christopher Arthurs
- Department of Biomedical Engineering, King's College London, London SE1 7EH, UK e-mail:
| | - Rajan Sharma
- Department of Cardiology, St. George's Hospital, London SW17 0QT, UK e-mail:
| | - Marjan Jahangiri
- Department of Cardiothoracic Surgery, St. George's Hospital, London SW17 0QT, UK e-mail:
| | - C Alberto Figueroa
- Department of Biomedical Engineering, King's College London, London SE1 7EH, UK.,Departments of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 e-mail:
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26
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Tsiklidis E, Sims C, Sinno T, Diamond SL. Multiscale systems biology of trauma-induced coagulopathy. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2018; 10:e1418. [PMID: 29485252 DOI: 10.1002/wsbm.1418] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/03/2018] [Accepted: 01/09/2018] [Indexed: 01/26/2023]
Abstract
Trauma with hypovolemic shock is an extreme pathological state that challenges the body to maintain blood pressure and oxygenation in the face of hemorrhagic blood loss. In conjunction with surgical actions and transfusion therapy, survival requires the patient's blood to maintain hemostasis to stop bleeding. The physics of the problem are multiscale: (a) the systemic circulation sets the global blood pressure in response to blood loss and resuscitation therapy, (b) local tissue perfusion is altered by localized vasoregulatory mechanisms and bleeding, and (c) altered blood and vessel biology resulting from the trauma as well as local hemodynamics control the assembly of clotting components at the site of injury. Building upon ongoing modeling efforts to simulate arterial or venous thrombosis in a diseased vasculature, computer simulation of trauma-induced coagulopathy is an emerging approach to understand patient risk and predict response. Despite uncertainties in quantifying the patient's dynamic injury burden, multiscale systems biology may help link blood biochemistry at the molecular level to multiorgan responses in the bleeding patient. As an important goal of systems modeling, establishing early metrics of a patient's high-dimensional trajectory may help guide transfusion therapy or warn of subsequent later stage bleeding or thrombotic risks. This article is categorized under: Analytical and Computational Methods > Computational Methods Biological Mechanisms > Regulatory Biology Models of Systems Properties and Processes > Mechanistic Models.
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Affiliation(s)
- Evan Tsiklidis
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Carrie Sims
- Department of Trauma Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Talid Sinno
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Scott L Diamond
- Department of Chemical and Biomolecular Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
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27
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28
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Piskin S, Unal G, Arnaz A, Sarioglu T, Pekkan K. Tetralogy of Fallot Surgical Repair: Shunt Configurations, Ductus Arteriosus and the Circle of Willis. Cardiovasc Eng Technol 2017; 8:107-119. [PMID: 28382440 PMCID: PMC5446850 DOI: 10.1007/s13239-017-0302-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 03/27/2017] [Indexed: 11/09/2022]
Abstract
In this study, hemodynamic performance of three novel shunt configurations that are considered for the surgical repair of tetralogy of Fallot (TOF) disease are investigated in detail. Clinical experience suggests that the shunt location, connecting angle, and its diameter can influence the post-operative physiology and the neurodevelopment of the neonatal patient. An experimentally validated second order computational fluid dynamics (CFD) solver and a parametric neonatal diseased great artery model that incorporates the ductus arteriosus (DA) and the full patient-specific circle of Willis (CoW) are employed. Standard truncated resistance CFD boundary conditions are compared with the full cerebral arterial system, which resulted 21, -13, and 37% difference in flow rate at the brachiocephalic, left carotid, and subclavian arteries, respectively. Flow splits at the aortic arch and cerebral arteries are calculated and found to change with shunt configuration significantly for TOF disease. The central direct shunt (direct shunt) has pulmonary flow 5% higher than central oblique shunt (oblique shunt) and 23% higher than modified Blalock Taussig shunt (RPA shunt) while the DA is closed. Maximum wall shear stress (WSS) in the direct shunt configuration is 9 and 60% higher than that of the oblique and RPA shunts, respectively. Patent DA, significantly eliminated the pulmonary flow control function of the shunt repair. These results suggests that, due to the higher flow rates at the pulmonary arteries, the direct shunt, rather than the central oblique, or right pulmonary artery shunts could be preferred by the surgeon. This extended model introduced new hemodynamic performance indices for the cerebral circulation that can correlate with the post-operative neurodevelopment quality of the patient.
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Affiliation(s)
- Senol Piskin
- Department of Mechanical Engineering, Koç University, Rumeli Feneri Kampüsü, Sarıyer, Istanbul, Turkey
| | - Gozde Unal
- Faculty of Engineering and Natural Sciences, Sabancı University, Tuzla, Istanbul, Turkey
| | - Ahmet Arnaz
- Department of Cardiovascular Surgery, Acıbadem Bakırköy Hospital, Istanbul, Turkey
| | - Tayyar Sarioglu
- Department of Pediatric Cardiovascular Surgery, School of Medicine, Acıbadem University, Istanbul, Turkey
| | - Kerem Pekkan
- Department of Mechanical Engineering, Koç University, Rumeli Feneri Kampüsü, Sarıyer, Istanbul, Turkey.
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29
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Pagiatakis C, Tardif JC, L'Allier PL, Mongrain R. Effect of stenosis eccentricity on the functionality of coronary bifurcation lesions-a numerical study. Med Biol Eng Comput 2017; 55:2079-2095. [PMID: 28500478 DOI: 10.1007/s11517-017-1653-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 04/25/2017] [Indexed: 01/10/2023]
Abstract
Interventional cardiologists still rely heavily on angiography for the evaluation of coronary lesion severity, despite its poor correlation with the presence of ischemia. In order to improve the accuracy of the current diagnostic procedures, an understanding of the relative influence of geometric characteristics on the induction of ischemia is required. This idea is especially important for coronary bifurcation lesions (CBLs), whose treatment is complex and is associated with high rates of peri- and post-procedural clinical events. Overall, it is unclear which geometric and morphological parameters of CBLs influence the onset of ischemia. More specifically, the effect of stenosis eccentricity is unknown. Computational fluid dynamic simulations, under a geometric multiscale framework, were executed for seven CBL configurations within the left main coronary artery bifurcation. Both concentric and eccentric stenosis profiles of mild to severe constriction were considered. By using a geometric multiscale framework, the fractional flow reserve, which is the gold-standard clinical diagnostic index, could be calculated and was compared between the eccentric and concentric profiles for each case. The results suggested that for configurations where the supplying vessel is stenosed, eccentricity could have a notable effect on and therefore be an important factor that influences configuration functionality.
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Affiliation(s)
- Catherine Pagiatakis
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, H3A 0C3, Canada. .,Montreal Heart Institute, 5000 Belanger Street, Montreal, Quebec, H1T 1C8, Canada.
| | - Jean-Claude Tardif
- Montreal Heart Institute, 5000 Belanger Street, Montreal, Quebec, H1T 1C8, Canada.,Faculty of Medicine, Université de Montréal - Pavillon Roger-Gaudry, 2900 Edouard-Montpetit Boulevard, Montreal, Quebec, H3T 1J4, Canada
| | - Philippe L L'Allier
- Montreal Heart Institute, 5000 Belanger Street, Montreal, Quebec, H1T 1C8, Canada.,Faculty of Medicine, Université de Montréal - Pavillon Roger-Gaudry, 2900 Edouard-Montpetit Boulevard, Montreal, Quebec, H3T 1J4, Canada
| | - Rosaire Mongrain
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, H3A 0C3, Canada.,Montreal Heart Institute, 5000 Belanger Street, Montreal, Quebec, H1T 1C8, Canada
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30
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Schmidt T, Rosenthal D, Reinhartz O, Riemer K, He F, Hsia TY, Marsden A, Kung E. Superior performance of continuous over pulsatile flow ventricular assist devices in the single ventricle circulation: A computational study. J Biomech 2017; 52:48-54. [DOI: 10.1016/j.jbiomech.2016.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/15/2016] [Accepted: 12/03/2016] [Indexed: 10/20/2022]
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31
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Riveros Perez E, Riveros R. Mathematical Analysis and Physical Profile of Blalock-Taussig Shunt and Sano Modification Procedure in Hypoplastic Left Heart Syndrome: Review of the Literature and Implications for the Anesthesiologist. Semin Cardiothorac Vasc Anesth 2017; 21:152-164. [PMID: 28118786 DOI: 10.1177/1089253216687857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The first stage of surgical treatment for hypoplastic left heart syndrome (HLHS) includes the creation of artificial systemic-to-pulmonary connections to provide pulmonary blood flow. The modified Blalock-Taussig (mBT) shunt has been the technique of choice for this procedure; however, a right ventricle-pulmonary artery (RV-PA) shunt has been introduced into clinical practice with encouraging but still conflicting outcomes when compared with the mBT shunt. The aim of this study is to explore mathematical modeling as a tool for describing physical profiles that could assist the surgical team in predicting complications related to stenosis and malfunction of grafts in an attempt to find correlations with clinical outcomes from clinical studies that compared both surgical techniques and to assist the anesthesiologist in making decisions to manage patients with this complex cardiac anatomy. Mathematical modeling to display the physical characteristics of the chosen surgical shunt is a valuable tool to predict flow patterns, shear stress, and rate distribution as well as energetic performance at the graft level and relative to ventricular efficiency. Such predictions will enable the surgical team to refine the technique so that hemodynamic complications be anticipated and prevented, and are also important for perioperative management by the anesthesia team.
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32
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Youssefi P, Sharma R, Figueroa CA, Jahangiri M. Functional assessment of thoracic aortic aneurysms - the future of risk prediction? Br Med Bull 2017; 121:61-71. [PMID: 27989994 PMCID: PMC5862296 DOI: 10.1093/bmb/ldw049] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/13/2016] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Treatment guidelines for the thoracic aorta concentrate on size, yet acute aortic dissection or rupture can occur when aortic size is below intervention criteria. Functional imaging and computational techniques are a means of assessing haemodynamic parameters involved in aortic pathology. SOURCES OF DATA Original articles, reviews, international guidelines. AREAS OF AGREEMENT Computational fluid dynamics and 4D flow MRI allow non-invasive assessment of blood flow parameters and aortic wall biomechanics. AREAS OF CONTROVERSY Aortic valve morphology (particularly bicuspid aortic valve) is associated with aneurysm of the ascending aorta, although the exact mechanism of aneurysm formation is not yet established. GROWING POINTS Haemodynamic assessment of the thoracic aorta has highlighted parameters which are linked with both clinical outcome and protein changes in the aortic wall. Wall shear stress, flow displacement and helicity are elevated in patients with bicuspid aortic valve, particularly at locations of aneurysm formation. AREAS TIMELY FOR DEVELOPING RESEARCH With further validation, functional assessment of the aorta may help identify patients at risk of aortic complications, and introduce new haemodynamic indices into management guidelines.
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Affiliation(s)
- Pouya Youssefi
- Department of Cardiothoracic Surgery & Cardiology, St. George's Hospital, St. George's University of London, Blackshaw Road, London, SW17 0QT, United Kingdom.,Department of Biomedical Engineering, Rayne Institute, St. Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Rajan Sharma
- Department of Cardiothoracic Surgery & Cardiology, St. George's Hospital, St. George's University of London, Blackshaw Road, London, SW17 0QT, United Kingdom
| | - C Alberto Figueroa
- Department of Biomedical Engineering, Rayne Institute, St. Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom.,Departments of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Marjan Jahangiri
- Department of Cardiothoracic Surgery & Cardiology, St. George's Hospital, St. George's University of London, Blackshaw Road, London, SW17 0QT, United Kingdom
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33
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Lee P, Carlson BE, Chesler N, Olufsen MS, Qureshi MU, Smith NP, Sochi T, Beard DA. Heterogeneous mechanics of the mouse pulmonary arterial network. Biomech Model Mechanobiol 2016; 15:1245-61. [PMID: 26792789 PMCID: PMC4956606 DOI: 10.1007/s10237-015-0757-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/25/2015] [Indexed: 10/22/2022]
Abstract
Individualized modeling and simulation of blood flow mechanics find applications in both animal research and patient care. Individual animal or patient models for blood vessel mechanics are based on combining measured vascular geometry with a fluid structure model coupling formulations describing dynamics of the fluid and mechanics of the wall. For example, one-dimensional fluid flow modeling requires a constitutive law relating vessel cross-sectional deformation to pressure in the lumen. To investigate means of identifying appropriate constitutive relationships, an automated segmentation algorithm was applied to micro-computerized tomography images from a mouse lung obtained at four different static pressures to identify the static pressure-radius relationship for four generations of vessels in the pulmonary arterial network. A shape-fitting function was parameterized for each vessel in the network to characterize the nonlinear and heterogeneous nature of vessel distensibility in the pulmonary arteries. These data on morphometric and mechanical properties were used to simulate pressure and flow velocity propagation in the network using one-dimensional representations of fluid and vessel wall mechanics. Moreover, wave intensity analysis was used to study effects of wall mechanics on generation and propagation of pressure wave reflections. Simulations were conducted to investigate the role of linear versus nonlinear formulations of wall elasticity and homogeneous versus heterogeneous treatments of vessel wall properties. Accounting for heterogeneity, by parameterizing the pressure/distention equation of state individually for each vessel segment, was found to have little effect on the predicted pressure profiles and wave propagation compared to a homogeneous parameterization based on average behavior. However, substantially different results were obtained using a linear elastic thin-shell model than were obtained using a nonlinear model that has a more physiologically realistic pressure versus radius relationship.
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Affiliation(s)
- Pilhwa Lee
- Department of Molecular and Integrative Physiology, University of Michigan, 2800 Plymouth Road, North Campus Research Center, Ann Arbor, MI, 48109-5622, USA
| | - Brian E Carlson
- Department of Molecular and Integrative Physiology, University of Michigan, 2800 Plymouth Road, North Campus Research Center, Ann Arbor, MI, 48109-5622, USA
| | - Naomi Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison, 2146 ECB; 1550 Engineering Drive, Madison, WI, 53706-1609, USA
| | - Mette S Olufsen
- Department of Mathematics, North Carolina State University, Campus Box 8205, Raleigh, NC, 27502, USA
| | - M Umar Qureshi
- Department of Mathematics, North Carolina State University, Campus Box 8205, Raleigh, NC, 27502, USA
| | - Nicolas P Smith
- Imaging Sciences and Biomedical Engineering Division, St Thomas' Hospital, King's College London, London, SE1 7EH, UK
- Faculty of Engineering, 20 Symonds St, Auckland, 1010, New Zealand
| | - Taha Sochi
- Imaging Sciences and Biomedical Engineering Division, St Thomas' Hospital, King's College London, London, SE1 7EH, UK
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, 2800 Plymouth Road, North Campus Research Center, Ann Arbor, MI, 48109-5622, USA.
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34
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Imai Y, Omori T, Shimogonya Y, Yamaguchi T, Ishikawa T. Numerical methods for simulating blood flow at macro, micro, and multi scales. J Biomech 2016; 49:2221-2228. [DOI: 10.1016/j.jbiomech.2015.11.047] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 11/07/2015] [Indexed: 02/04/2023]
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35
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Neidlin M, Corsini C, Sonntag SJ, Schulte-Eistrup S, Schmitz-Rode T, Steinseifer U, Pennati G, Kaufmann TAS. Hemodynamic analysis of outflow grafting positions of a ventricular assist device using closed-loop multiscale CFD simulations: Preliminary results. J Biomech 2016; 49:2718-2725. [PMID: 27298155 DOI: 10.1016/j.jbiomech.2016.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 05/30/2016] [Accepted: 06/01/2016] [Indexed: 11/17/2022]
Abstract
Subclavian arteries are a possible alternate location for left ventricular assist device (LVAD) outflow grafts due to easier surgical access and application in high risk patients. As vascular blood flow mechanics strongly influence the clinical outcome, insights into the hemodynamics during LVAD support can be used to evaluate different grafting locations. In this study, the feasibility of left and right subclavian artery (SA) grafting was investigated for the HeartWare HVAD with a numerical multiscale model. A 3-D CFD model of the aortic arch was coupled to a lumped parameter model of the cardiovascular system under LVAD support. Grafts in the left and right SA were placed at three different anastomoses angles (90°, 60° and 30°). Additionally, standard grafting of the ascending and descending aorta was modelled. Full support LVAD (5l/min) and partial support LVAD (3l/min) in co-pulsation and counter-pulsation mode were analysed. The grafting positions were investigated regarding coronary and cerebral perfusion. Furthermore, the influence of the anastomosis angle on wall shear stress (WSS) was evaluated. Grafting of left or right subclavian arteries has similar hemodynamic performance in comparison to standard cannula positions. Angularity change of the graft anastomosis from 90° to 30° slightly increases the coronary and cerebral blood flow by 6-9% while significantly reduces the WSS by 35%. Cannulation of the SA is a feasible anastomosis location for the HVAD in the investigated vessel geometry.
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Affiliation(s)
- Michael Neidlin
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany; Enmodes GmbH, Aachen, Germany.
| | - Chiara Corsini
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering ''Giulio Natta'', Politecnico di Milano, Milano, Italy
| | - Simon J Sonntag
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany; Enmodes GmbH, Aachen, Germany
| | | | - Thomas Schmitz-Rode
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Ulrich Steinseifer
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany
| | - Giancarlo Pennati
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering ''Giulio Natta'', Politecnico di Milano, Milano, Italy
| | - Tim A S Kaufmann
- Department of Cardiovascular Engineering, Institute of Applied Medical Engineering, Helmholtz Institute, RWTH Aachen University, Aachen, Germany; Enmodes GmbH, Aachen, Germany
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36
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Laadhari A, Quarteroni A. Numerical modeling of heart valves using resistive Eulerian surfaces. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2016; 32:e02743. [PMID: 26255787 DOI: 10.1002/cnm.2743] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 05/22/2015] [Accepted: 08/04/2015] [Indexed: 06/04/2023]
Abstract
The goal of this work is the development and numerical implementation of a mathematical model describing the functioning of heart valves. To couple the pulsatile blood flow with a highly deformable thin structure (the valve's leaflets), a resistive Eulerian surfaces framework is adopted. A lumped-parameter model helps to couple the movement of the leaflets with the blood dynamics. A reduced circulation model describes the systemic hemodynamics and provides a physiological pressure profile at the downstream boundary of the valve. The resulting model is relatively simple to describe for a healthy valve and pathological heart valve functioning while featuring an affordable computational burden. Efficient time and spatial discretizations are considered and implemented. We address in detail the main features of the proposed method, and we report several numerical experiments for both two-dimensional and three-dimensional cases with the aim of illustrating its accuracy. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Aymen Laadhari
- Computer Vision Laboratory, Institut für Bildverarbeitung, Department of Information Technology and Electrical Engineering, Swiss Federal Institute of Technology-ETHZ, CH-8092, Zürich, Switzerland
| | - Alfio Quarteroni
- Modeling and Scientific Computing, Mathematics Institute of Computational Science and Engineering (MATHICSE), École Polytechnique Fédérale de Lausanne-EPFL, CH-1015, Lausanne, Switzerland
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37
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Abstract
PURPOSE OF REVIEW Recent methodological advances in computational simulations are enabling increasingly realistic simulations of hemodynamics and physiology, driving increased clinical utility. We review recent developments in the use of computational simulations in pediatric and congenital heart disease, describe the clinical impact in modeling in single-ventricle patients, and provide an overview of emerging areas. RECENT FINDINGS Multiscale modeling combining patient-specific hemodynamics with reduced order (i.e., mathematically and computationally simplified) circulatory models has become the de-facto standard for modeling local hemodynamics and 'global' circulatory physiology. We review recent advances that have enabled faster solutions, discuss new methods (e.g., fluid structure interaction and uncertainty quantification), which lend realism both computationally and clinically to results, highlight novel computationally derived surgical methods for single-ventricle patients, and discuss areas in which modeling has begun to exert its influence including Kawasaki disease, fetal circulation, tetralogy of Fallot (and pulmonary tree), and circulatory support. SUMMARY Computational modeling is emerging as a crucial tool for clinical decision-making and evaluation of novel surgical methods and interventions in pediatric cardiology and beyond. Continued development of modeling methods, with an eye towards clinical needs, will enable clinical adoption in a wide range of pediatric and congenital heart diseases.
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38
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Blanco PJ, Ares GD, Urquiza SA, Feijóo RA. On the effect of preload and pre-stretch on hemodynamic simulations: an integrative approach. Biomech Model Mechanobiol 2015; 15:593-627. [PMID: 26329641 DOI: 10.1007/s10237-015-0712-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 07/28/2015] [Indexed: 10/23/2022]
Abstract
In this work, we address the simulation of three-dimensional arterial blood flow and its effect on the stress state of arterial walls. The novel contribution is the unprecedented combination of several modeling techniques to account for (1) the fact that known configurations for the arterial wall are in a preloaded state, (2) the compliance of the vessel segments, (3) proper boundary data over the non-physical interfaces resulting from the isolation of an arterial district from the rest of the arterial tree, (4) the presence of surrounding tissues in which the vessel is embedded and (5) residual stress state due to pre-stretch. Firstly, we formulate both the forward mechanical problem when the reference (zero-load) configuration is assumed to be known and, the preload problem arising when the known domain is a configuration at equilibrium with a certain load state (typically due to internal pressure and tethering forces). Then, two additional complexities are faced: the fluid-structure interaction problem that follows when the compliant vessels are coupled with the blood flow, and the introduction of non-physical boundaries coming from the artificial isolation of the arterial district from the original vessel. This, in turn, posses the problem of coupling dimensionally heterogeneous models to incorporate the effect of upstream and downstream systemic impedances. Additionally, a viscoelastic support on the external surface of the vessel is also incorporated. Two examples are presented to quantify in a physiologically consistent scenario the differences in simulation results when either considering or not the preload state of arterial walls. These computational simulations shed light on the validity of simplifying hypotheses in most hemodynamic models.
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Affiliation(s)
- Pablo J Blanco
- Laboratório Nacional de Computação Científica, Av. Getúlio Vargas 333, Petrópolis, 25651-075, Brazil.,National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
| | - Gonzalo D Ares
- Laboratório Nacional de Computação Científica, Av. Getúlio Vargas 333, Petrópolis, 25651-075, Brazil. .,National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil.
| | - Santiago A Urquiza
- National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil.,Facultad de Ingeniería, Universidad Nacional de Mar del Plata, Av. J.B. Justo 4302, 7600, Mar del Plata, Argentina
| | - Raúl A Feijóo
- Laboratório Nacional de Computação Científica, Av. Getúlio Vargas 333, Petrópolis, 25651-075, Brazil.,National Institute of Science and Technology in Medicine Assisted by Scientific Computing, INCT-MACC, Petrópolis, Brazil
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39
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Redaelli A. A Model of Health: Mathematical modeling tools play an important role in optimizing new treatment options for heart disease. IEEE Pulse 2015; 6:27-32. [PMID: 26186050 DOI: 10.1109/mpul.2015.2428683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Models are crucial in the biomedical sciences since they provide information that is not otherwise accessible and help in discriminating among possible schemes of interpretation of complex phenomena. Italian research teams have been very active in this field with important contributions in the area of heart mechanics, which typically requires sophisticated three-dimensional (3-D) approaches to simulate wall and blood fluid mechanics. These models are increasingly being used to assess the patient-specific pathological scenario and to predict possible therapy outcomes.
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40
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LIU JINLONG, SUN QI, HONG HAIFA, SUN YANJUN, LIU JINFEN, QIAN YI, WANG QIAN, UMEZU MITSUO. MEDICAL IMAGE-BASED HEMODYNAMIC ANALYSIS FOR MODIFIED BLALOCK–TAUSSIG SHUNT. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415500359] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Modified Blalock–Taussig (mB–T) shunt is an effective palliative surgical method in the treatment of cyanotic congenital heart diseases. Although the surgical technique has improved over the years, it is still a challenge to control appropriate blood flow through the conduit. The formation of thrombosis in the conduit after the mB–T shunt may lead to severe desaturation or reoperation in some cases. Here, we applied the method of computational fluid dynamics (CFD) to study a patient-specific case based on medical images after the mB–T shunt. The real-time velocities derived from echocardiography and the pulsatile pressure waves measured during the operation were utilized as boundary conditions to physiologically capture the blood flow information in simulation. The calculated results were coincident with clinical measurements. Local pressure, blood flow distribution, streamlines, wall shear stress (WSS) and centrifugal force in the bended conduit were investigated. The results indicate that pressure decreases greatly through the conduit. The combined action of pulsatile pressure and WSS may lead to the damage of blood cells. The computational hemodynamics can be applied in future studies of establishing quantitative standards to evaluate surgical outcomes of the mB–T shunt.
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Affiliation(s)
- JINLONG LIU
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai, P. R. China
| | - QI SUN
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai, P. R. China
| | - HAIFA HONG
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai, P. R. China
| | - YANJUN SUN
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai, P. R. China
| | - JINFEN LIU
- Department of Cardiothoracic Surgery, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai, P. R. China
| | - YI QIAN
- Australian School of Advanced Medicine, Macquarie University, North Ryde 2109, Sydney, NSW, Australia
| | - QIAN WANG
- Department of Medical Imaging, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, 1678 Dongfang Road, Shanghai, P. R. China
| | - MITSUO UMEZU
- Centre for Advanced Biomedical Sciences, TWIns, Waseda University, TWIns 03C-301, ASMeW Lab, 2-2 Wakamatsucho, Shinjuku 162-8480, Tokyo, Japan
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41
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Kung E, Pennati G, Migliavacca F, Hsia TY, Figliola R, Marsden A, Giardini A. A simulation protocol for exercise physiology in Fontan patients using a closed loop lumped-parameter model. J Biomech Eng 2015; 136:1852723. [PMID: 24658635 DOI: 10.1115/1.4027271] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 03/24/2014] [Indexed: 11/08/2022]
Abstract
BACKGROUND Reduced exercise capacity is nearly universal among Fontan patients, though its etiology is not yet fully understood. While previous computational studies have attempted to model Fontan exercise, they did not fully account for global physiologic mechanisms nor directly compare results against clinical and physiologic data. METHODS In this study, we developed a protocol to simulate Fontan lower-body exercise using a closed-loop lumped-parameter model describing the entire circulation. We analyzed clinical exercise data from a cohort of Fontan patients, incorporated previous clinical findings from literature, quantified a comprehensive list of physiological changes during exercise, translated them into a computational model of the Fontan circulation, and designed a general protocol to model Fontan exercise behavior. Using inputs of patient weight, height, and if available, patient-specific reference heart rate (HR) and oxygen consumption, this protocol enables the derivation of a full set of parameters necessary to model a typical Fontan patient of a given body-size over a range of physiologic exercise levels. RESULTS In light of previous literature data and clinical knowledge, the model successfully produced realistic trends in physiological parameters with exercise level. Applying this method retrospectively to a set of clinical Fontan exercise data, direct comparison between simulation results and clinical data demonstrated that the model successfully reproduced the average exercise response of a cohort of typical Fontan patients. CONCLUSION This work is intended to offer a foundation for future advances in modeling Fontan exercise, highlight the needs in clinical data collection, and provide clinicians with quantitative reference exercise physiologies for Fontan patients.
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42
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Corsini C, Baker C, Baretta A, Biglino G, Hlavacek AM, Hsia TY, Kung E, Marsden A, Migliavacca F, Vignon-Clementel I, Pennati G. Integration of Clinical Data Collected at Different Times for Virtual Surgery in Single Ventricle Patients: A Case Study. Ann Biomed Eng 2014; 43:1310-20. [DOI: 10.1007/s10439-014-1113-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/05/2014] [Indexed: 11/25/2022]
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43
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Blanco PJ, Watanabe SM, Passos MARF, Lemos PA, Feijóo RA. An anatomically detailed arterial network model for one-dimensional computational hemodynamics. IEEE Trans Biomed Eng 2014; 62:736-53. [PMID: 25347874 DOI: 10.1109/tbme.2014.2364522] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Simulation platforms are increasingly becoming complementary tools for cutting-edge cardiovascular research. The interplay among structural properties of the arterial wall, morphometry, anatomy, wave propagation phenomena, and ultimately, cardiovascular diseases continues to be poorly understood. Accurate models are powerful tools to shed light on these open problems. We developed an anatomically detailed computational model of the arterial vasculature to conduct 1-D blood flow simulations to serve as simulation infrastructure to aid cardiovascular research. An average arterial vasculature of a man was outlined in 3-D space to serve as geometrical substrate for the mathematical model. The architecture of this model comprises almost every arterial vessel acknowledged in the medical/anatomical literature, with a resolution down to the luminal area of perforator arteries. Over 2000 arterial vessels compose the model. Anatomical, physiological, and mechanical considerations were employed for the set up of model parameters and to determine criteria for blood flow distribution. Computational fluid dynamics was used to simulate blood flow and wave propagation phenomena in such arterial network. A sensitivity analysis was developed to unveil the contributions of model parameters to the conformation of the pressure waveforms. In addition, parameters were modified to target model to a patient-specific scenario. On the light of the knowledge domain, we conclude that the present model features excellent descriptive and predictive capabilities in both patient-generic and patient-specific cases, presenting a new step toward integrating an unprecedented anatomical description, morphometric, and simulations data to help in understanding complex arterial blood flow phenomena and related cardiovascular diseases.
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44
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Liang F, Sughimoto K, Matsuo K, Liu H, Takagi S. Patient-specific assessment of cardiovascular function by combination of clinical data and computational model with applications to patients undergoing Fontan operation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:1000-1018. [PMID: 24753499 DOI: 10.1002/cnm.2641] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 11/01/2013] [Accepted: 03/22/2014] [Indexed: 06/03/2023]
Abstract
The assessment of cardiovascular function is becoming increasingly important for the care of patients with single-ventricle defects. However, most measurement methods available in the clinical setting cannot provide a separate measure of cardiac function and loading conditions. In the present study, a numerical method has been proposed to compensate for the limitations of clinical measurements. The main idea was to estimate the parameters of a cardiovascular model by fitting model simulations to patient-specific clinical data via parameter optimization. Several strategies have been taken to establish a well-posed parameter optimization problem, including clinical data-matched model development, parameter selection based on an extensive sensitivity analysis, and proper choice of parameter optimization algorithm. The numerical experiments confirmed the ability of the proposed parameter optimization method to uniquely determine the model parameters given an arbitrary set of clinical data. The method was further tested in four patients undergoing the Fontan operation. Obtained results revealed a prevalence of ventricular abnormalities in the patient cohort and at the same time demonstrated the presence of marked inter-patient differences and preoperative to postoperative changes in cardiovascular function. Because the method allows a quick assessment and makes use of clinical data available in clinical practice, its clinical application is promising.
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Affiliation(s)
- Fuyou Liang
- SJTU-CU International Cooperative Research Center, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
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Liang F, Senzaki H, Kurishima C, Sughimoto K, Inuzuka R, Liu H. Hemodynamic performance of the Fontan circulation compared with a normal biventricular circulation: a computational model study. Am J Physiol Heart Circ Physiol 2014; 307:H1056-72. [DOI: 10.1152/ajpheart.00245.2014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The physiological limitations of the Fontan circulation have been extensively addressed in the literature. Many studies emphasized the importance of pulmonary vascular resistance in determining cardiac output (CO) but gave little attention to other cardiovascular properties that may play considerable roles as well. The present study was aimed to systemically investigate the effects of various cardiovascular properties on clinically relevant hemodynamic variables (e.g., CO and central venous pressure). To this aim, a computational modeling method was employed. The constructed models provided a useful tool for quantifying the hemodynamic effects of any cardiovascular property of interest by varying the corresponding model parameters in model-based simulations. Herein, the Fontan circulation was studied compared with a normal biventricular circulation so as to highlight the unique characteristics of the Fontan circulation. Based on a series of numerical experiments, it was found that 1) pulmonary vascular resistance, ventricular diastolic function, and systemic vascular compliance play a major role, while heart rate, ventricular contractility, and systemic vascular resistance play a secondary role in the regulation of CO in the Fontan circulation; 2) CO is nonlinearly related to any single cardiovascular property, with their relationship being simultaneously influenced by other cardiovascular properties; and 3) the stability of central venous pressure is significantly reduced in the Fontan circulation. The findings suggest that the hemodynamic performance of the Fontan circulation is codetermined by various cardiovascular properties and hence a full understanding of patient-specific cardiovascular conditions is necessary to optimize the treatment of Fontan patients.
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Affiliation(s)
- Fuyou Liang
- Shanghai Jiao Tong University-Chiba University International Cooperative Research Center, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Hideaki Senzaki
- Department of Pediatrics and Pediatric Cardiology, Saitama Medical Center, Saitama Medical University, Kamoda, Kawagoe, Saitama, Japan
| | - Clara Kurishima
- Department of Pediatrics and Pediatric Cardiology, Saitama Medical Center, Saitama Medical University, Kamoda, Kawagoe, Saitama, Japan
| | - Koichi Sughimoto
- Department of Cardiac Surgery, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Ryo Inuzuka
- Pediatrics, University Hospital University of Tokyo, Tokyo, Japan; and
| | - Hao Liu
- Shanghai Jiao Tong University-Chiba University International Cooperative Research Center, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- Graduate School of Engineering, Chiba University, Inage, Chiba, Japan
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Kung E, Perry JC, Davis C, Migliavacca F, Pennati G, Giardini A, Hsia TY, Marsden A. Computational modeling of pathophysiologic responses to exercise in Fontan patients. Ann Biomed Eng 2014; 43:1335-47. [PMID: 25260878 DOI: 10.1007/s10439-014-1131-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 09/19/2014] [Indexed: 11/29/2022]
Abstract
Reduced exercise capacity is nearly universal among Fontan patients. Although many factors have emerged as possible contributors, the degree to which each impacts the overall hemodynamics is largely unknown. Computational modeling provides a means to test hypotheses of causes of exercise intolerance via precisely controlled virtual experiments and measurements. We quantified the physiological impacts of commonly encountered, clinically relevant dysfunctions introduced to the exercising Fontan system via a previously developed lumped-parameter model of Fontan exercise. Elevated pulmonary arterial pressure was observed in all cases of dysfunction, correlated with lowered cardiac output (CO), and often mediated by elevated atrial pressure. Pulmonary vascular resistance was not the most significant factor affecting exercise performance as measured by CO. In the absence of other dysfunctions, atrioventricular valve insufficiency alone had significant physiological impact, especially under exercise demands. The impact of isolated dysfunctions can be linearly summed to approximate the combined impact of several dysfunctions occurring in the same system. A single dominant cause of exercise intolerance was not identified, though several hypothesized dysfunctions each led to variable decreases in performance. Computational predictions of performance improvement associated with various interventions should be weighed against procedural risks and potential complications, contributing to improvements in routine patient management protocol.
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Affiliation(s)
- Ethan Kung
- Mechanical Engineering Department, Clemson University, Clemson, SC, 29634, USA
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Corsini C, Biglino G, Schievano S, Hsia TY, Migliavacca F, Pennati G, Taylor AM. The effect of modified Blalock-Taussig shunt size and coarctation severity on coronary perfusion after the Norwood operation. Ann Thorac Surg 2014; 98:648-54. [PMID: 24906601 DOI: 10.1016/j.athoracsur.2014.04.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/31/2014] [Accepted: 04/08/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND The size of the modified Blalock-Taussig shunt and the additional presence of aortic coarctation can affect the hemodynamics of the Norwood physiology. Multiscale modeling was used to gather insight into the effects of these variables, in particular on coronary perfusion. METHODS A model was reconstructed from cardiac magnetic resonance imaging data of a representative patient, and then simplified with computer-aided design software. Changes were systematically imposed to the semi-idealized three-dimensional model, resulting in a family of nine models (3-, 3.5-, and 4-mm shunt diameter; 0%, 60%, and 90% coarctation severity). Each model was coupled to a lumped parameter network representing the remainder of the circulation to run multiscale simulations. Simulations were repeated including the effect of preserved cerebral perfusion. RESULTS The concomitant presence of a large shunt and tight coarctation was detrimental in terms of coronary perfusion (13.4% maximal reduction, 1.07 versus 0.927 mL/s) and oxygen delivery (29% maximum reduction, 422 versus 300 mL·min(-1)·m(-2)). A variation in the ratio of pulmonary to systemic blood flow from 0.9 to 1.6 also indicated a "stealing" phenomenon to the detriment of the coronary circulation. A difference could be further appreciated in the computational ventricular pressure-volume loops, with augmented systolic pressures and decreased stroke volumes for tighter coarctation. Accounting for constant cerebral perfusion did not produce substantially different results. CONCLUSIONS Multiscale simulations performed in a parametric fashion revealed a reduction in coronary perfusion in the presence of a large modified Blalock-Taussig shunt and severe coarctation in Norwood patients.
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Affiliation(s)
- Chiara Corsini
- Laboratory of Biological Structure Mechanics, Politecnico di Milano, Milan, Italy
| | - Giovanni Biglino
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, and Great Ormond Street Hospital for Children, NHS Foundation Trust, London, United Kingdom.
| | - Silvia Schievano
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, and Great Ormond Street Hospital for Children, NHS Foundation Trust, London, United Kingdom
| | - Tain-Yen Hsia
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, and Great Ormond Street Hospital for Children, NHS Foundation Trust, London, United Kingdom
| | | | - Giancarlo Pennati
- Laboratory of Biological Structure Mechanics, Politecnico di Milano, Milan, Italy
| | - Andrew M Taylor
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, and Great Ormond Street Hospital for Children, NHS Foundation Trust, London, United Kingdom
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Computational Models of Aortic Coarctation in Hypoplastic Left Heart Syndrome: Considerations on Validation of a Detailed 3D model. Int J Artif Organs 2014; 37:371-81. [DOI: 10.5301/ijao.5000332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/16/2014] [Indexed: 11/20/2022]
Abstract
Background Reliability of computational models for cardiovascular investigations strongly depends on their validation against physical data. This study aims to experimentally validate a computational model of complex congenital heart disease (i.e., surgically palliated hypoplastic left heart syndrome with aortic coarctation) thus demonstrating that hemodynamic information can be reliably extrapolated from the model for clinically meaningful investigations. Materials and methods A patient-specific aortic arch model was tested in a mock circulatory system and the same flow conditions were re-created in silico, by setting an appropriate lumped parameter network (LPN) attached to the same three-dimensional (3D) aortic model (i.e., multi-scale approach). The model included a modified Blalock-Taussig shunt and coarctation of the aorta. Different flow regimes were tested as well as the impact of uncertainty in viscosity. Results Computational flow and pressure results were in good agreement with the experimental signals, both qualitatively, in terms of the shape of the waveforms, and quantitatively (mean aortic pressure 62.3 vs. 65.1 mmHg, 4.8% difference; mean aortic flow 28.0 vs. 28.4% inlet flow, 1.4% difference; coarctation pressure drop 30.0 vs. 33.5 mmHg, 10.4% difference), proving the reliability of the numerical approach. It was observed that substantial changes in fluid viscosity or using a turbulent model in the numerical simulations did not significantly affect flows and pressures of the investigated physiology. Results highlighted how the non-linear fluid dynamic phenomena occurring in vitro must be properly described to ensure satisfactory agreement. Conclusions This study presents methodological considerations for using experimental data to preliminarily set up a computational model, and then simulate a complex congenital physiology using a multi-scale approach.
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Blood flow distribution in an anatomically detailed arterial network model: criteria and algorithms. Biomech Model Mechanobiol 2014; 13:1303-30. [DOI: 10.1007/s10237-014-0574-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 03/14/2014] [Indexed: 12/11/2022]
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Sousa LC, Castro CF, António CC, Santos A, Santos R, Castro P, Azevedo E, Tavares JMR. Haemodynamic conditions of patient-specific carotid bifurcation based on ultrasound imaging. COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING-IMAGING AND VISUALIZATION 2014. [DOI: 10.1080/21681163.2013.875486] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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