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Li G, Zhou M, Huang X, Ji C, Fan T, Xu J, Xiong H, Huang Y. Time delays between physiological signals in interpreting the body's responses to intermittent hypoxia in obstructive sleep apnea. Physiol Meas 2024; 45:055008. [PMID: 38688301 DOI: 10.1088/1361-6579/ad45ac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 04/30/2024] [Indexed: 05/02/2024]
Abstract
Objective.Intermittent hypoxia, the primary pathology of obstructive sleep apnea (OSA), causes cardiovascular responses resulting in changes in hemodynamic parameters such as stroke volume (SV), blood pressure (BP), and heart rate (HR). However, previous studies have produced very different conclusions, such as suggesting that SV increases or decreases during apnea. A key reason for drawing contrary conclusions from similar measurements may be due to ignoring the time delay in acquiring response signals. By analyzing the signals collected during hypoxia, we aim to establish criteria for determining the delay time between the onset of apnea and the onset of physiological parameter response.Approach.We monitored oxygen saturation (SpO2), transcutaneous oxygen pressure (TcPO2), and hemodynamic parameters SV, HR, and BP, during sleep in 66 patients with different OSA severity to observe body's response to hypoxia and determine the delay time of above parameters. Data were analyzed using the Kruskal-Wallis test, Quade test, and Spearman test.Main results.We found that simultaneous acquisition of various parameters inevitably involved varying degrees of response delay (7.12-25.60 s). The delay time of hemodynamic parameters was significantly shorter than that of SpO2and TcPO2(p< 0.01). OSA severity affected the response delay of SpO2, TcPO2, SV, mean BP, and HR (p< 0.05). SV delay time was negatively correlated with the apnea-hypopnea index (r= -0.4831,p< 0.0001).Significance.The real body response should be determined after removing the effect of delay time, which is the key to solve the problem of drawing contradictory conclusions from similar studies. The methods and important findings presented in this study provide key information for revealing the true response of the cardiovascular system during hypoxia, indicating the importance of proper signal analysis for correctly interpreting the cardiovascular hemodynamic response phenomena and exploring their physiological and pathophysiological mechanisms.
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Affiliation(s)
- Geng Li
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
| | - Mengwei Zhou
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
| | - Xiaoqing Huang
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
| | - Changjin Ji
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
| | - Tingting Fan
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
| | - Jinkun Xu
- Department of Otorhinopharyngology-Head and Neck Surgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing 102218, People's Republic of China
| | - Huahui Xiong
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
| | - Yaqi Huang
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, People's Republic of China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, People's Republic of China
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Tobin N, Good BC, Plasencia JD, Fogel MA, Weiss WJ, Manning KB. Computational Investigation of Anastomosis Options of a Right-Heart Pump to Patient Specific Pulmonary Arteries. Ann Biomed Eng 2022; 50:929-940. [PMID: 35451680 DOI: 10.1007/s10439-022-02969-2] [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: 06/15/2021] [Accepted: 04/12/2022] [Indexed: 11/30/2022]
Abstract
Patients with Fontan circulation have increased risk of heart failure, but are not always candidates for heart transplant, leading to the development of the subpulmonic Penn State Fontan Circulation Assist Device. The aim of this study was to use patient-specific computational fluid dynamics simulations to evaluate anastomosis options for implanting this device. Simulations were performed of the pre-surgical anatomy as well as four surgical options: a T-junction and three Y-grafts. Cases were evaluated based on several fluid-dynamic quantities. The impact of imbalanced left-right pulmonary flow distribution was also investigated. Results showed that a 12-mm Y-graft was the most energy efficient. However, an 8-mm graft showed more favorable wall shear stress distribution, indicating lower risk of thrombosis and endothelial damage. The 8-mm Y-grafts also showed a more balanced pulmonary flow split, and lower residence time, also indicating lower thrombosis risk. The relative performance of the surgical options was largely unchanged whether or not the pulmonary vascular resistance remained imbalanced post-implantation.
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Affiliation(s)
- Nicolas Tobin
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | - Bryan C Good
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA
| | | | - Mark A Fogel
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - William J Weiss
- Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, 17033, USA
| | - Keefe B Manning
- Department of Biomedical Engineering, The Pennsylvania State University, 122 Chemical and Biomedical Engineering Building, University Park, PA, 16802-4400, USA. .,Department of Surgery, Penn State Hershey Medical Center, Hershey, PA, 17033, USA.
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Rijnberg FM, Westenberg JJM, van Assen HC, Juffermans JF, Kroft LJM, van den Boogaard PJ, Terol Espinosa de Los Monteros C, Warmerdam EG, Leiner T, Grotenhuis HB, Jongbloed MRM, Hazekamp MG, Roest AAW, Lamb HJ. 4D flow cardiovascular magnetic resonance derived energetics in the Fontan circulation correlate with exercise capacity and CMR-derived liver fibrosis/congestion. J Cardiovasc Magn Reson 2022; 24:21. [PMID: 35346249 PMCID: PMC8962091 DOI: 10.1186/s12968-022-00854-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 03/15/2022] [Indexed: 12/12/2022] Open
Abstract
AIM This study explores the relationship between in vivo 4D flow cardiovascular magnetic resonance (CMR) derived blood flow energetics in the total cavopulmonary connection (TCPC), exercise capacity and CMR-derived liver fibrosis/congestion. BACKGROUND The Fontan circulation, in which both caval veins are directly connected with the pulmonary arteries (i.e. the TCPC) is the palliative approach for single ventricle patients. Blood flow efficiency in the TCPC has been associated with exercise capacity and liver fibrosis using computational fluid dynamic modelling. 4D flow CMR allows for assessment of in vivo blood flow energetics, including kinetic energy (KE) and viscous energy loss rate (EL). METHODS Fontan patients were prospectively evaluated between 2018 and 2021 using a comprehensive cardiovascular and liver CMR protocol, including 4D flow imaging of the TCPC. Peak oxygen consumption (VO2) was determined using cardiopulmonary exercise testing (CPET). Iron-corrected whole liver T1 (cT1) mapping was performed as a marker of liver fibrosis/congestion. KE and EL in the TCPC were computed from 4D flow CMR and normalized for inflow. Furthermore, blood flow energetics were compared between standardized segments of the TCPC. RESULTS Sixty-two Fontan patients were included (53% male, 17.3 ± 5.1 years). Maximal effort CPET was obtained in 50 patients (peak VO2 27.1 ± 6.2 ml/kg/min, 56 ± 12% of predicted). Both KE and EL in the entire TCPC (n = 28) were significantly correlated with cT1 (r = 0.50, p = 0.006 and r = 0.39, p = 0.04, respectively), peak VO2 (r = - 0.61, p = 0.003 and r = - 0.54, p = 0.009, respectively) and % predicted peak VO2 (r = - 0.44, p = 0.04 and r = - 0.46, p = 0.03, respectively). Segmental analysis indicated that the most adverse flow energetics were found in the Fontan tunnel and left pulmonary artery. CONCLUSIONS Adverse 4D flow CMR derived KE and EL in the TCPC correlate with decreased exercise capacity and increased levels of liver fibrosis/congestion. 4D flow CMR is promising as a non-invasive screening tool for identification of patients with adverse TCPC flow efficiency.
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Affiliation(s)
- Friso M Rijnberg
- Department of Cardiothoracic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands.
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hans C van Assen
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Joe F Juffermans
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Lucia J M Kroft
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | | | - Tim Leiner
- Department of Radiology, Utrecht Medical Center, Utrecht, The Netherlands
| | - Heynric B Grotenhuis
- Department of Pediatric Cardiology, Utrecht Medical Center, Utrecht, The Netherlands
| | - Monique R M Jongbloed
- Department of Cardiology and Anatomy and Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Mark G Hazekamp
- Department of Cardiothoracic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA, Leiden, The Netherlands
| | - Arno A W Roest
- Department of Pediatric Cardiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Hildo J Lamb
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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van der Woude SFS, Rijnberg FM, Hazekamp MG, Jongbloed MRM, Kenjeres S, Lamb HJ, Westenberg JJM, Roest AAW, Wentzel JJ. The Influence of Respiration on Blood Flow in the Fontan Circulation: Insights for Imaging-Based Clinical Evaluation of the Total Cavopulmonary Connection. Front Cardiovasc Med 2021; 8:683849. [PMID: 34422920 PMCID: PMC8374887 DOI: 10.3389/fcvm.2021.683849] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/05/2021] [Indexed: 12/18/2022] Open
Abstract
Congenital heart disease is the most common birth defect and functionally univentricular heart defects represent the most severe end of this spectrum. The Fontan circulation provides an unique solution for single ventricle patients, by connecting both caval veins directly to the pulmonary arteries. As a result, the pulmonary circulation in Fontan palliated patients is characterized by a passive, low-energy circulation that depends on increased systemic venous pressure to drive blood toward the lungs. The absence of a subpulmonary ventricle led to the widely believed concept that respiration, by sucking blood to the pulmonary circulation during inspiration, is of great importance as a driving force for antegrade blood flow in Fontan patients. However, recent studies show that respiration influences pulsatility, but has a limited effect on net forward flow in the Fontan circulation. Importantly, since MRI examination is recommended every 2 years in Fontan patients, clinicians should be aware that most conventional MRI flow sequences do not capture the pulsatility of the blood flow as a result of the respiration. In this review, the unique flow dynamics influenced by the cardiac and respiratory cycle at multiple locations within the Fontan circulation is discussed. The impact of (not) incorporating respiration in different MRI flow sequences on the interpretation of clinical flow parameters will be covered. Finally, the influence of incorporating respiration in advanced computational fluid dynamic modeling will be outlined.
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Affiliation(s)
- Séline F S van der Woude
- Department of Cardiology, Biomedical Engineering, Biomechanics Laboratory, Rotterdam, Netherlands
| | - Friso M Rijnberg
- Department of Cardiothoracic Surgery, Leiden University Medical Center, Leiden, Netherlands
| | - Mark G Hazekamp
- Department of Cardiothoracic Surgery, Leiden University Medical Center, Leiden, Netherlands
| | - Monique R M Jongbloed
- Department of Anatomy, Embryology and Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Sasa Kenjeres
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology and J. M. Burgerscentrum Research School for Fluid Mechanics, Delft, Netherlands
| | - Hildo J Lamb
- Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Arno A W Roest
- Department of Pediatric Cardiology, Leiden University Medical Center, Leiden, Netherlands
| | - Jolanda J Wentzel
- Department of Cardiology, Biomedical Engineering, Biomechanics Laboratory, Rotterdam, Netherlands
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Engineering Perspective on Cardiovascular Simulations of Fontan Hemodynamics: Where Do We Stand with a Look Towards Clinical Application. Cardiovasc Eng Technol 2021; 12:618-630. [PMID: 34114202 DOI: 10.1007/s13239-021-00541-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 04/30/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND Cardiovascular simulations for patients with single ventricles undergoing the Fontan procedure can assess patient-specific hemodynamics, explore surgical advances, and develop personalized strategies for surgery and patient care. These simulations have not yet been broadly accepted as a routine clinical tool owing to a number of limitations. Numerous approaches have been explored to seek innovative solutions for improving methodologies and eliminating these limitations. PURPOSE This article first reviews the current state of cardiovascular simulations of Fontan hemodynamics. Then, it will discuss the technical progress of Fontan simulations with the emphasis of its clinical impact, noting that substantial improvements have been made in the considerations of patient-specific anatomy, flow, and blood rheology. The article concludes with insights into potential future directions involving clinical validation, uncertainty quantification, and computational efficiency. The advancements in these aspects could promote the clinical usage of Fontan simulations, facilitating its integration into routine clinical practice.
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A Tribute to Ajit Yoganathan's Cardiovascular Fluid Mechanics Lab: A Survey of Its Contributions to Our Understanding of the Physiology and Management of Single-Ventricle Patients. Cardiovasc Eng Technol 2021; 12:631-639. [PMID: 34018153 DOI: 10.1007/s13239-021-00540-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/30/2021] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Among patients with congenital heart disease, those born with only a single working ventricle represent a particularly complex sub-population, typically requiring multiple surgeries and suffering from high levels of mortality and morbidity. Their cardiac care is complex and has evolved considerably since surgical palliation was first introduced more than 50 years ago. Improvements in treatment have been driven both by growing clinical experience and by knowledge gained through experimental and computational studies of blood flow in these patients. The Cardiovascular Fluid Mechanics Lab at the Georgia Institute of Technology, founded 30 years ago by Dr. Ajit Yoganathan, has pioneered work in this field. METHODS In this review, key contributions of Dr. Yoganathan's Cardiovascular Fluid Dynamics Lab are surveyed, including experimental flow loop studies as well as computational fluid dynamics analyses that address many of the critical challenges that cardiologists and surgeons face in treating these patients, including how to reconstruct cardiovascular anatomy to minimize power loss, balance blood flow distribution at key bifurcation points, and avoid other unfavorable hemodynamic conditions. CONCLUSIONS Among many contributions in this field, work from the Cardiovascular Fluid Mechanics Lab has led to novel medical devices and patient-specific computational modeling workflows and software tools. These key contributions from this group have enhanced our understanding of the physiology and management of single-ventricle patients.
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Is Doppler Echocardiography Adequate for Surgical Planning of Single Ventricle Patients? Cardiovasc Eng Technol 2021; 12:606-617. [PMID: 33931807 DOI: 10.1007/s13239-021-00533-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 03/12/2021] [Indexed: 12/13/2022]
Abstract
PURPOSE Surgical planning has shown great potential for optimizing outcomes for patients affected by single ventricle (SV) malformations. Phase-contrast magnetic resonance imaging (PC-MRI) is the routine technique used for flow acquisition in the surgical planning paradigm. However, PC-MRI may suffer from possible artifacts in certain cases; furthermore, this technology may not be readily available for patients in low and lower-middle-income countries. Therefore, this study aims to investigate the effectiveness of using Doppler echocardiography (echo-Doppler) for flow acquisitions of SV surgical planning. METHODS This study included eight patients whose blood flow data was acquired by both PC-MRI and echo-Doppler. A virtual surgery platform was used to generate two surgical options for each patient: (1) a traditional Fontan conduit and (2) a Y-graft. Computational fluid dynamics (CFD) simulations were conducted using the two flow acquisitions to assess clinically relevant hemodynamic metrics: indexed power loss (iPL) and hepatic flow distribution (HFD). RESULTS Differences exist in flow data acquired by PC-MRI and echo-Doppler, but no statistical significance was obtained. Flow fields, therefore, exhibit discrepancies between simulations using flow acquisitions by PC-MRI and echo-Doppler. In virtual surgery, the two surgical options were ranked based on these metrics. No difference was observed in the ranking of surgical options between using different flow acquisitions. CONCLUSION Doppler echocardiography is an adequate alternative approach to acquire flow data for SV surgical planning. This finding encourages broader usage of SV surgical planning with echo-Doppler when MRI may present artifacts or is not available, especially in low and lower-middle-income countries.
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Fluid-Structure Interaction Simulation of an Intra-Atrial Fontan Connection. BIOLOGY 2020; 9:biology9120412. [PMID: 33255292 PMCID: PMC7760396 DOI: 10.3390/biology9120412] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 12/15/2022]
Abstract
Simple Summary A fluid-structure interaction (FSI) simulation of an intra-atrial Fontan connection was performed. Power loss and pressure drop results fluctuated less during the FSI simulation than during the simulation run with rigid walls, but there were no observable differences in time-averaged pressure drop, connection power loss or hepatic flow distribution. These results suggested that employing a rigid wall is a reasonable assumption when evaluating time-averaged hemodynamic quantities of the Fontan connection under resting breath-held flow conditions. Abstract Total cavopulmonary connection (TCPC) hemodynamics has been hypothesized to be associated with long-term complications in single ventricle heart defect patients. Rigid wall assumption has been commonly used when evaluating TCPC hemodynamics using computational fluid dynamics (CFD) simulation. Previous study has evaluated impact of wall compliance on extra-cardiac TCPC hemodynamics using fluid-structure interaction (FSI) simulation. However, the impact of ignoring wall compliance on the presumably more compliant intra-atrial TCPC hemodynamics is not fully understood. To narrow this knowledge gap, this study aims to investigate impact of wall compliance on an intra-atrial TCPC hemodynamics. A patient-specific model of an intra-atrial TCPC is simulated with an FSI model. Patient-specific 3D TCPC anatomies were reconstructed from transverse cardiovascular magnetic resonance images. Patient-specific vessel flow rate from phase-contrast magnetic resonance imaging (MRI) at the Fontan pathway and the superior vena cava under resting condition were prescribed at the inlets. From the FSI simulation, the degree of wall deformation was compared with in vivo wall deformation from phase-contrast MRI data as validation of the FSI model. Then, TCPC flow structure, power loss and hepatic flow distribution (HFD) were compared between rigid wall and FSI simulation. There were differences in instantaneous pressure drop, power loss and HFD between rigid wall and FSI simulations, but no difference in the time-averaged quantities. The findings of this study support the use of a rigid wall assumption on evaluation of time-averaged intra-atrial TCPC hemodynamic metric under resting breath-held condition.
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Wei ZA, Johnson C, Trusty P, Stephens M, Wu W, Sharon R, Srimurugan B, Kottayil BP, Sunil GS, Fogel MA, Yoganathan AP, Kappanayil M. Comparison of Fontan Surgical Options for Patients with Apicocaval Juxtaposition. Pediatr Cardiol 2020; 41:1021-1030. [PMID: 32377893 PMCID: PMC7325867 DOI: 10.1007/s00246-020-02353-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/23/2020] [Indexed: 12/22/2022]
Abstract
Apicocaval juxtaposition (ACJ) is a rare form of viscerocardiac malpositions in association with single-ventricle congenital heart defects. The Fontan surgery is the common palliation, and possible surgical options include ipsilateral, contralateral, and intra-atrial conduits. Concerns include lower hemodynamic performances or risks of conduit compression by the cardiac mass. This study investigates the hemodynamics and clinical outcomes of ACJ patients and potential surgical improvements. Ten consecutive ACJ patients were included, along with a reference cohort of ten non-ACJ patients. Magnetic resonance images were acquired at 6 ± 0.6 year follow-up for anatomical analysis and hemodynamic assessments using computational fluid dynamics. Metrics of interest are deformation index (DI), indexed power loss (iPL), and hepatic flow distribution (HFDoff). A "virtual" surgery was performed to explore potential hemodynamic improvements using a straightened conduit. DI for ACJ patients fell within the DI range of non-ACJ patients. Contralateral conduits had insignificantly higher iPL (0.070 [0.032,0.137]) than ipsilateral conduits (0.041 [0.013,0.095]) and non-ACJ conduits (0.034 [0.011,0.061]). HFDoff was similar for the ipsilateral (21 [12,35]), contralateral (26 [7,41]), and non-ACJ Fontan conduits (17 [0,48]). Virtual surgery demonstrated that a straightened conduit reduced HFDoff and iPL for the contralateral and ipsilateral conduits, potentially leading to improved clinical outcomes. In this limited sample, the hemodynamic performance of ACJ patients was not significantly different from their non-ACJ counterparts. The use of a straightened conduit option could potentially improve patient outcomes. Additionally, the fear of significant compression of conduits for ACJ patients was unsupported.
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Affiliation(s)
- Zhenglun Alan Wei
- Department of Biomedical Engineering, Georgia Institute of Technology, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Camille Johnson
- Department of Biomedical Engineering, Georgia Institute of Technology, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Phillip Trusty
- Department of Biomedical Engineering, Georgia Institute of Technology, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Morgan Stephens
- Department of Biomedical Engineering, Georgia Institute of Technology, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Wenjun Wu
- Department of Biomedical Engineering, Georgia Institute of Technology, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Ritchie Sharon
- Amrita Institute of Medical Sciences and Research Centre, Kochi, India
| | - Balaji Srimurugan
- Amrita Institute of Medical Sciences and Research Centre, Kochi, India
| | | | - G S Sunil
- Amrita Institute of Medical Sciences and Research Centre, Kochi, India
| | - Mark A Fogel
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ajit P Yoganathan
- Department of Biomedical Engineering, Georgia Institute of Technology, Suite 200, 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
| | - Mahesh Kappanayil
- Amrita Institute of Medical Sciences and Research Centre, Kochi, India
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Non-Newtonian Effects on Patient-Specific Modeling of Fontan Hemodynamics. Ann Biomed Eng 2020; 48:2204-2217. [PMID: 32372365 DOI: 10.1007/s10439-020-02527-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 04/29/2020] [Indexed: 12/15/2022]
Abstract
The Fontan procedure is a common palliative surgery for congenital single ventricle patients. In silico and in vitro patient-specific modeling approaches are widely utilized to investigate potential improvements of Fontan hemodynamics that are related to long-term complications. However, there is a lack of consensus regarding the use of non-Newtonian rheology, warranting a systematic investigation. This study conducted in silico patient-specific modeling for twelve Fontan patients, using a Newtonian and a non-Newtonian model for each patient. Differences were quantified by examining clinically relevant metrics: indexed power loss (iPL), indexed viscous dissipation rate (iVDR), hepatic flow distribution (HFD), and regions of low wall shear stress (AWSS). Four sets of "non-Newtonian importance factors" were calculated to explore their effectiveness in identifying the non-Newtonian effect. No statistical differences were observed in iPL, iVDR, and HFD between the two models at the population-level, but large inter-patient variations exist. Significant differences were detected regarding AWSS, and its correlations with non-Newtonian importance factors were discussed. Additionally, simulations using the non-Newtonian model were computationally faster than those using the Newtonian model. These findings distinguish good importance factors for identifying non-Newtonian rheology and encourage the use of a non-Newtonian model to assess Fontan hemodynamics.
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Chen X, Yuan H, Liu J, Zhang N, Zhou C, Huang M, Jian Q, Zhuang J. Hemodynamic Effects of Additional Pulmonary Blood Flow on Glenn and Fontan Circulation. Cardiovasc Eng Technol 2020; 11:268-282. [PMID: 32072439 DOI: 10.1007/s13239-020-00459-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 02/10/2020] [Indexed: 10/25/2022]
Abstract
PURPOSE Additional pulmonary blood flow (APBF) can provide better pulsating blood flow and systemic arterial oxygen saturation, while low blood pulsation and low oxygen saturation are defects of the Fontan and Glenn procedure. Studying the hemodynamic effect of APBF is beneficial for clinical decisions. This study aimed to explore the effect on particle washout, as well as the differences among the sensitivities of both different hemodynamic parameters and different procedures to APBF. METHODS The patient-specific clinical datasets of a patient who underwent bilateral bidirectional Glenn (BBDG) with APBF were enrolled in this study, and using these datasets, Glenn- and Fontan-type artery models were reconstructed. A series of parameters, including the total caval flow pulsatility index (TCPI), indexed energy loss (iPL), wall shear stress (WSS), systemic arterial oxygen saturation (Satart), particle washout time (WOT), pressure in the right superior vena cava (PRSVC), pulmonary flow distribution (PFD) and hepatic flow distribution (HFD), were computed from computational fluid dynamic (CFD) simulation to evaluate the hemodynamic effect of APBF. RESULTS The result showed that APBF led to better iPL and Satart but worse PRSVC and heart load accompanied by a great impact on HFD, making hepatic flow easier to perfuse the side without MPA and APBF. The increase in the APBF rate also effectively results in larger flow pulsation, region velocity, and wall shear stress and lower WOT, and this effect may be more effective for patients with persistent left superior vena cava (PLSVC). However, APBF might have little effect on PFD. Furthermore, APBF might affect WOT, iPL and HFD more significantly than PRSVC and has a greater improvement effect in patients with poorer iPL and WOT. CONCLUSIONS Moderate APBF is not only a measure to promote pulmonary artery growth and systemic arterial oxygen saturation but also an effective method against endothelial dysfunction and thrombosis. However, moderate APBF is patient-specific and should be determined based on hemodynamic preference that leads to desired patient outcomes, and care should be taken to prevent PRSVC and heart load from being too high as well as an imbalance in HFD.
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Affiliation(s)
- Xiangyu Chen
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, 510000, China
| | - Haiyun Yuan
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Department of Cardiovascular Surgery, Guangdong Provincial People's Hospital, Guangdong Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, 510000, China
| | - Jiawei Liu
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, 510000, China
| | - Neichuan Zhang
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, 510000, China
| | - Chengbin Zhou
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Department of Cardiovascular Surgery, Guangdong Provincial People's Hospital, Guangdong Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, 510000, China
| | - Meiping Huang
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Department of Catheterization Lab, Guangdong Provincial People's Hospital, Guangdong Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Qifei Jian
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, 510000, China.
| | - Jian Zhuang
- Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Department of Cardiovascular Surgery, Guangdong Provincial People's Hospital, Guangdong Cardiovascular Institute, Guangdong Academy of Medical Sciences, Guangzhou, 510000, China.
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Impact of Free-Breathing Phase-Contrast MRI on Decision-Making in Fontan Surgical Planning. J Cardiovasc Transl Res 2019; 13:640-647. [DOI: 10.1007/s12265-019-09930-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 10/21/2019] [Indexed: 11/26/2022]
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Wei ZA, Huddleston C, Trusty PM, Singh-Gryzbon S, Fogel MA, Veneziani A, Yoganathan AP. Analysis of Inlet Velocity Profiles in Numerical Assessment of Fontan Hemodynamics. Ann Biomed Eng 2019; 47:2258-2270. [PMID: 31236791 DOI: 10.1007/s10439-019-02307-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 06/08/2019] [Indexed: 12/16/2022]
Abstract
Computational fluid dynamic (CFD) simulations are widely utilized to assess Fontan hemodynamics that are related to long-term complications. No previous studies have systemically investigated the effects of using different inlet velocity profiles in Fontan simulations. This study implements real, patient-specific velocity profiles for numerical assessment of Fontan hemodynamics using CFD simulations. Four additional, artificial velocity profiles were used for comparison: (1) flat, (2) parabolic, (3) Womersley, and (4) parabolic with inlet extensions [to develop flow before entering the total cavopulmonary connection (TCPC)]. The differences arising from the five velocity profiles, as well as discrepancies between the real and each of the artificial velocity profiles, were quantified by examining clinically important metrics in TCPC hemodynamics: power loss (PL), viscous dissipation rate (VDR), hepatic flow distribution, and regions of low wall shear stress. Statistically significant differences were observed in PL and VDR between simulations using real and flat velocity profiles, but differences between those using real velocity profiles and the other three artificial profiles did not reach statistical significance. These conclusions suggest that the artificial velocity profiles (2)-(4) are acceptable surrogates for real velocity profiles in Fontan simulations, but parabolic profiles are recommended because of their low computational demands and prevalent applicability.
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Affiliation(s)
- Zhenglun Alan Wei
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Suite 232, Atlanta, GA, 30313-2412, USA
| | - Connor Huddleston
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Phillip M Trusty
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Suite 232, Atlanta, GA, 30313-2412, USA
| | - Shelly Singh-Gryzbon
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Suite 232, Atlanta, GA, 30313-2412, USA
| | - Mark A Fogel
- Department of Cardiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Alessandro Veneziani
- Department of Mathematics, Department of Computer Science, Emory University, Atlanta, GA, USA
| | - Ajit P Yoganathan
- Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Suite 232, Atlanta, GA, 30313-2412, USA.
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