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Turner ME, Blum KM, Watanabe T, Schwarz EL, Nabavinia M, Leland JT, Villarreal DJ, Schwartzman WE, Chou TH, Baker PB, Matsumura G, Krishnamurthy R, Yates AR, Hor KN, Humphrey JD, Marsden AL, Stacy MR, Shinoka T, Breuer CK. Tissue engineered vascular grafts are resistant to the formation of dystrophic calcification. Nat Commun 2024; 15:2187. [PMID: 38467617 PMCID: PMC10928115 DOI: 10.1038/s41467-024-46431-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/22/2024] [Indexed: 03/13/2024] Open
Abstract
Advancements in congenital heart surgery have heightened the importance of durable biomaterials for adult survivors. Dystrophic calcification poses a significant risk to the long-term viability of prosthetic biomaterials in these procedures. Herein, we describe the natural history of calcification in the most frequently used vascular conduits, expanded polytetrafluoroethylene grafts. Through a retrospective clinical study and an ovine model, we compare the degree of calcification between tissue-engineered vascular grafts and polytetrafluoroethylene grafts. Results indicate superior durability in tissue-engineered vascular grafts, displaying reduced late-term calcification in both clinical studies (p < 0.001) and animal models (p < 0.0001). Further assessments of graft compliance reveal that tissue-engineered vascular grafts maintain greater compliance (p < 0.0001) and distensibility (p < 0.001) than polytetrafluoroethylene grafts. These properties improve graft hemodynamic performance, as validated through computational fluid dynamics simulations. We demonstrate the promise of tissue engineered vascular grafts, remaining compliant and distensible while resisting long-term calcification, to enhance the long-term success of congenital heart surgeries.
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Affiliation(s)
- Mackenzie E Turner
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Molecular Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Kevin M Blum
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Ohio State University College of Medicine, Columbus, OH, USA
| | - Tatsuya Watanabe
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Erica L Schwarz
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Mahboubeh Nabavinia
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Joseph T Leland
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Delaney J Villarreal
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Ohio State University College of Medicine, Columbus, OH, USA
- Biomedical Sciences Graduate Program, The Ohio State University College of Medicine, Columbus, OH, USA
| | - William E Schwartzman
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- The Ohio State University College of Medicine, Columbus, OH, USA
| | - Ting-Heng Chou
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, Taipei City, Taiwan
| | - Peter B Baker
- Pathology Department at Nationwide Children's Hospital and The Ohio State University, Columbus, OH, USA
| | - Goki Matsumura
- Department of Medical Safety Management, Tokyo Women's Medical University, Tokyo, Japan
| | - Rajesh Krishnamurthy
- Department of Radiology, Nationwide Children's Hospital and The Ohio State University, Columbus, OH, USA
| | - Andrew R Yates
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Kan N Hor
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
- The Heart Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Alison L Marsden
- Departments of Pediatrics and Bioengineering, Stanford University, Stanford, CA, USA
| | - Mitchel R Stacy
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Surgery, The Ohio State University College of Medicine, Columbus, OH, USA
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Toshiharu Shinoka
- Center for Regenerative Medicine, 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
| | - Christopher K Breuer
- Center for Regenerative Medicine, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
- Department of Surgery, The Ohio State University College of Medicine, Columbus, OH, USA.
- Department of Surgery, Nationwide Children's Hospital, Columbus, OH, USA.
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Weiss AJ, Panduro AO, Schwarz EL, Sexton ZA, Lan IS, Geisbush TR, Marsden AL, Telischak NA. A matched-pair case control study identifying hemodynamic predictors of cerebral aneurysm growth using computational fluid dynamics. Front Physiol 2023; 14:1300754. [PMID: 38162830 PMCID: PMC10757566 DOI: 10.3389/fphys.2023.1300754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024] Open
Abstract
Introduction: Initiation and progression of cerebral aneurysms is known to be driven by complex interactions between biological and hemodynamic factors, but the hemodynamic mechanism which drives aneurysm growth is unclear. We employed robust modeling and computational methods, including temporal and spatial convergence studies, to study hemodynamic characteristics of cerebral aneurysms and identify differences in these characteristics between growing and stable aneurysms. Methods: Eleven pairs of growing and non-growing cerebral aneurysms, matched in both size and location, were modeled from MRA and CTA images, then simulated using computational fluid dynamics (CFD). Key hemodynamic characteristics, including wall shear stress (WSS), oscillatory shear index (OSI), and portion of the aneurysm under low shear, were evaluated. Statistical analysis was then performed using paired Wilcoxon rank sum tests. Results: The portion of the aneurysm dome under 70% of the parent artery mean wall shear stress was higher in growing aneurysms than in stable aneurysms and had the highest significance among the tested metrics (p = 0.08). Other metrics of area under low shear had similar levels of significance. Discussion: These results align with previously observed hemodynamic trends in cerebral aneurysms, indicating a promising direction for future study of low shear area and aneurysm growth. We also found that mesh resolution significantly affected simulated WSS in cerebral aneurysms. This establishes that robust computational modeling methods are necessary for high fidelity results. Together, this work demonstrates that complex hemodynamics are at play within cerebral aneurysms, and robust modeling and simulation methods are needed to further study this topic.
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Affiliation(s)
- Allyson J. Weiss
- Department of Mechanical Engineering, Stanford University, Stanford, CA, United States
| | - Aaron O. Panduro
- Department of Biochemistry, California State University, Fresno, CA, United States
| | - Erica L. Schwarz
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Zachary A. Sexton
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Ingrid S. Lan
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Thomas. R. Geisbush
- Department of Radiology, School of Medicine, Stanford University, Stanford, CA, United States
| | - Alison L. Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, United States
- Department of Pediatrics, School of Medicine, Stanford University, Stanford, CA, United States
| | - Nicholas A. Telischak
- Department of Radiology, School of Medicine, Stanford University, Stanford, CA, United States
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Schwarz EL, Pfaller MR, Szafron JM, Latorre M, Lindsey SE, Breuer CK, Humphrey JD, Marsden AL. A Fluid-Solid-Growth Solver for Cardiovascular Modeling. Comput Methods Appl Mech Eng 2023; 417:116312. [PMID: 38044957 PMCID: PMC10691594 DOI: 10.1016/j.cma.2023.116312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
We implement full, three-dimensional constrained mixture theory for vascular growth and remodeling into a finite element fluid-structure interaction (FSI) solver. The resulting "fluid-solid-growth" (FSG) solver allows long term, patient-specific predictions of changing hemodynamics, vessel wall morphology, tissue composition, and material properties. This extension from short term (FSI) to long term (FSG) simulations increases clinical relevance by enabling mechanobioloigcally-dependent studies of disease progression in complex domains.
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Affiliation(s)
- Erica L Schwarz
- Department of Bioengineering, Stanford Univeristy, Stanford, CA 94306, USA
| | - Martin R Pfaller
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
| | - Jason M Szafron
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
| | - Marcos Latorre
- Center for Research and Innovation in Bioengineering, Universitat Politècnica de València, València 46022, Spain
| | - Stephanie E Lindsey
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
| | - Christopher K Breuer
- Department of Surgery, Nationwide Children's Hospital, Columbus, OH 43210, USA
- Center for Regenerative Medicine, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH 43215, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale Univeristy, New Haven, CT 06520, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford Univeristy, Stanford, CA 94306, USA
- Department of Pediatrics - Cardiology, Stanford Univeristy, Stanford, CA 94306, USA
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Schwarz EL, Pegolotti L, Pfaller MR, Marsden AL. Beyond CFD: Emerging methodologies for predictive simulation in cardiovascular health and disease. Biophys Rev (Melville) 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Tran K, Feliciano KB, Yang W, Schwarz EL, Marsden AL, Dalman RL, Lee JT. Patient-specific changes in aortic hemodynamics is associated with thrombotic risk after fenestrated endovascular aneurysm repair with large diameter endografts. JVS Vasc Sci 2022; 3:219-231. [PMID: 35647564 PMCID: PMC9133635 DOI: 10.1016/j.jvssci.2022.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/06/2022] [Indexed: 12/24/2022] Open
Abstract
Background The durability of fenestrated endovascular aneurysm repair (fEVAR) has been threatened by thrombotic complications. In the present study, we used patient-specific computational fluid dynamic (CFD) simulation to investigate the effect of the endograft diameter on hemodynamics after fEVAR and explore the hypothesis that diameter-dependent alterations in aortic hemodynamics can predict for thrombotic events. Methods A single-institutional retrospective study was performed of patients who had undergone fEVAR for juxtarenal aortic aneurysms. The patients were stratified into large diameter (34-36 mm) and small diameter (24-26 mm) endograft groups. Patient-specific CFD simulations were performed using three-dimensional paravisceral aortic models created from computed tomographic images with allometrically scaled boundary conditions. Aortic time-averaged wall shear stress (TAWSS) and residence time (RT) were computed and correlated with future thrombotic complications (eg, renal stent occlusion, development of significant intraluminal graft thrombus). Results A total of 36 patients (14 with a small endograft and 22 with a large endograft) were included in the present study. The patients treated with large endografts had experienced a higher incidence of thrombotic complications compared with small endografts (45.5% vs 7.1%; P = .016). Large endografts were associated with a lower postoperative aortic TAWSS (1.45 ± 0.76 dynes/cm2 vs 3.16 ± 1.24 dynes/cm2; P < .001) and longer aortic RT (0.78 ± 0.30 second vs 0.34 ± 0.08 second; P < .001). In the large endograft group, a reduction >0.39 dynes/cm2 in aortic TAWSS demonstrated discriminatory power for thrombotic complications (area under the receiver operating characteristic curve, 0.77). An increased aortic RT of ≥0.05 second had similar accuracy for predicting thrombotic complications (area under the receiver operating characteristic curve, 0.78). The odds of thrombotic complications were significantly higher if patients had met the hemodynamic threshold changes in aortic TAWSS (odds ratio, 7.0; 95% confidence interval, 1.1-45.9) and RT (odds ratio, 8.0; 95% confidence interval, 1.13-56.8). Conclusions Patient-specific CFD simulation of fEVAR in juxtarenal aortic aneurysms demonstrated significant endograft diameter-dependent differences in aortic hemodynamics. A postoperative reduction in TAWSS and an increased RT correlated with future thrombotic events after large-diameter endograft implantation. Patient-specific simulation of hemodynamics provides a novel method for thrombotic risk stratification after fEVAR. The durability of fenestrated endovascular aneurysm repair (fEVAR) has been threatened by thrombotic complications. Using patient-specific computational flow simulation, the present retrospective study of 36 patients with juxtarenal aortic aneurysms treated with fEVAR identified several endograft diameter-dependent changes in aortic hemodynamics associated with thrombotic complications. A postoperative reduction in aortic wall shear stress and increased particle residence time correlated with the development of intraluminal graft thrombus and renal stent occlusion in patients treated with large diameter (>34 mm) endografts. These computationally estimated hemodynamic parameters could provide a novel method for patient-specific risk stratification for adverse events after fEVAR.
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Affiliation(s)
- Kenneth Tran
- Division of Vascular Surgery, Stanford University School of Medicine, Stanford, CA
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
- Correspondence: Kenneth Tran, MD, Department of Vascular Surgery, Stanford University School of Medicine, 300 Pasteur Dr, Ste H3600, Stanford, CA 94305-5851
| | - K. Brennan Feliciano
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA
| | - Weiguang Yang
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA
| | - Erica L. Schwarz
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA
| | - Alison L. Marsden
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA
| | - Ronald L. Dalman
- Division of Vascular Surgery, Stanford University School of Medicine, Stanford, CA
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
| | - Jason T. Lee
- Division of Vascular Surgery, Stanford University School of Medicine, Stanford, CA
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA
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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. Publisher Correction: Hemodynamic performance of tissue-engineered vascular grafts in Fontan patients. NPJ Regen Med 2021; 6:47. [PMID: 34385470 PMCID: PMC8360958 DOI: 10.1038/s41536-021-00157-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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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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: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Yuzyuk T, Lozier B, Schwarz EL, Viau K, Kish-Trier E, De Biase I. Intra-individual variability of long-chain fatty acids (C12-C24) in plasma and red blood cells. Prostaglandins Leukot Essent Fatty Acids 2018; 135:30-38. [PMID: 30103929 DOI: 10.1016/j.plefa.2018.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 12/17/2022]
Abstract
Long-chain fatty acids (LCFA) play key roles in mammalian cells as sources of energy, structural components and signaling molecules. Given their importance in numerous physiological processes, the roles of LCFAs in health and disease have been extensively investigated. In the majority of studies, correlations are established using a single measurement in plasma or red blood cells (RBCs). Although a few studies have reported on reproducibility of individual fatty acid measurements, the comprehensive analysis of intra-individual LCFA variability has not been performed. Therefore, our goal was to determine intra-individual variability for the 22 most abundant LCFAs in both plasma and RBC samples collected from healthy individuals on a regular diet after overnight fasting. The measurements of LCFAs in RBCs were consistent throughout the course of study reflecting long-term nutritional status. In contrast, the results in plasma showed considerable LCFA intra-individual variability, even between fatty acids of the same type. Plasma intra-individual variability for omega-3 alpha-linolenic and eicosapentaenoic acids in some participants were >40% whereas the variability of docosahexaenoic acid was consistently <12.8%. Omega-6 linoleic and arachidonic acids also showed low variability in plasma. The results suggest that some LCFAs have less variability and would be more reliable as biomarkers. Reliability of biomarkers can have a profound impact on the research outcomes. Intra-individual variability of LCFAs should be taken into consideration in designing, conducting and interpreting results of clinical studies.
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Affiliation(s)
- T Yuzyuk
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA; ARUP Institute of Clinical & Experimental Pathology, Salt Lake City, UT, USA.
| | - B Lozier
- ARUP Institute of Clinical & Experimental Pathology, Salt Lake City, UT, USA
| | - E L Schwarz
- ARUP Institute of Clinical & Experimental Pathology, Salt Lake City, UT, USA
| | - K Viau
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - E Kish-Trier
- ARUP Institute of Clinical & Experimental Pathology, Salt Lake City, UT, USA; Navigen, Salt Lake City, UT, USA (present affiliation)
| | - I De Biase
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA; ARUP Institute of Clinical & Experimental Pathology, Salt Lake City, UT, USA
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9
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Zahid S, Whyte KN, Schwarz EL, Blake RC, Boyle PM, Chrispin J, Prakosa A, Ipek EG, Pashakhanloo F, Halperin HR, Calkins H, Berger RD, Nazarian S, Trayanova NA. Feasibility of using patient-specific models and the "minimum cut" algorithm to predict optimal ablation targets for left atrial flutter. Heart Rhythm 2016; 13:1687-98. [PMID: 27108938 DOI: 10.1016/j.hrthm.2016.04.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND Left atrial flutter (LAFL) occurs in patients after atrial fibrillation ablation. Identification of optimal ablation targets to terminate LAFL remains challenging. OBJECTIVE The purpose of this study was to use patient-specific models to simulate LAFL and predict optimal ablation targets using a novel approach based on flow network theory. METHODS Late gadolinium-enhanced cardiac magnetic resonance scans from 10 patients with LAFL were used to construct atrial models incorporating fibrosis by investigators blinded to procedural findings. Rapid pacing was applied in silico to induce LAFL. In each LAFL, we represented reentrant wave propagation as an electric flow network and identified the "minimum cut" (MC), which was the smallest amount of tissue that separated the flow into 2 discontinuous components. In silico ablation was applied at MCs, and targets were compared to those that terminated LAFL during catheter ablation. RESULTS Patient-specific atrial models were successfully generated from patient scans. LAFL was induced in 7 of 10 models. Ablation of MCs terminated LAFL in 4 models and produced new, slower LAFL morphologies in the other 3. For the latter cases, flow analysis was repeated to identify MCs of emergent LAFLs. Ablation of these MCs terminated emergent LAFLs. The MC-based ablation lesions in simulations were similar in length and location to ablation targets that terminated LAFL during catheter ablation for these 7 patients. CONCLUSION Personalized atrial simulations can predict ablation targets for LAFL. These simulations provide a powerful tool for planning ablation procedures and may reduce procedural times and complications.
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Affiliation(s)
- Sohail Zahid
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Kaitlyn N Whyte
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Erica L Schwarz
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Robert C Blake
- CardioSolv Ablation Technologies Inc, Baltimore, Maryland
| | - Patrick M Boyle
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Jonathan Chrispin
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Adityo Prakosa
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Esra G Ipek
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Farhad Pashakhanloo
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Henry R Halperin
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hugh Calkins
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ronald D Berger
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Saman Nazarian
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Epidemiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Natalia A Trayanova
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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Zahid S, Cochet H, Boyle PM, Schwarz EL, Whyte KN, Vigmond EJ, Dubois R, Hocini M, Haïssaguerre M, Jaïs P, Trayanova NA. Patient-derived models link re-entrant driver localization in atrial fibrillation to fibrosis spatial pattern. Cardiovasc Res 2016; 110:443-54. [PMID: 27056895 DOI: 10.1093/cvr/cvw073] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 03/31/2016] [Indexed: 12/19/2022] Open
Abstract
AIMS The mechanisms underlying persistent atrial fibrillation (AF) in patients with atrial fibrosis are poorly understood. The goal of this study was to use patient-derived atrial models to test the hypothesis that AF re-entrant drivers (RDs) persist only in regions with specific fibrosis patterns. METHODS AND RESULTS Twenty patients with persistent AF (PsAF) underwent late gadolinium-enhanced MRI to detect the presence of atrial fibrosis. Segmented images were used to construct personalized 3D models of the fibrotic atria with biophysically realistic atrial electrophysiology. In each model, rapid pacing was applied to induce AF. AF dynamics were analysed and RDs were identified using phase mapping. Fibrosis patterns in RD regions were characterized by computing maps of fibrosis density (FD) and entropy (FE). AF was inducible in 13/20 models and perpetuated by few RDs (2.7 ± 1.5) that were spatially confined (trajectory of phase singularities: 7.6 ± 2.3 mm). Compared with the remaining atrial tissue, regions where RDs persisted had higher FE (IQR: 0.42-0.60 vs. 0.00-0.40, P < 0.05) and FD (IQR: 0.59-0.77 vs. 0.00-0.33, P < 0.05). Machine learning classified RD and non-RD regions based on FD and FE and identified a subset of fibrotic boundary zones present in 13.8 ± 4.9% of atrial tissue where 83.5 ± 2.4% of all RD phase singularities were located. CONCLUSION Patient-derived models demonstrate that AF in fibrotic substrates is perpetuated by RDs persisting in fibrosis boundary zones characterized by specific regional fibrosis metrics (high FE and FD). These results provide new insights into the mechanisms that sustain PsAF and could pave the way for personalized, MRI-based management of PsAF.
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Affiliation(s)
- Sohail Zahid
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Hubert Cochet
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, INSERM U1045, Bordeaux, France Hôpital Cardiologique du Haut-Lévêque, CHU Bordeaux, Université de Bordeaux, Bordeaux, France
| | - Patrick M Boyle
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Erica L Schwarz
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kaitlyn N Whyte
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Edward J Vigmond
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, INSERM U1045, Bordeaux, France
| | - Rémi Dubois
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, INSERM U1045, Bordeaux, France
| | - Mélèze Hocini
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, INSERM U1045, Bordeaux, France Hôpital Cardiologique du Haut-Lévêque, CHU Bordeaux, Université de Bordeaux, Bordeaux, France
| | - Michel Haïssaguerre
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, INSERM U1045, Bordeaux, France Hôpital Cardiologique du Haut-Lévêque, CHU Bordeaux, Université de Bordeaux, Bordeaux, France
| | - Pierre Jaïs
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, INSERM U1045, Bordeaux, France Hôpital Cardiologique du Haut-Lévêque, CHU Bordeaux, Université de Bordeaux, Bordeaux, France
| | - Natalia A Trayanova
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Stevenson DA, Schwarz EL, Carey JC, Viskochil DH, Hanson H, Bauer S, Weng HYC, Greene T, Reinker K, Swensen J, Chan RJ, Yang FC, Senbanjo L, Yang Z, Mao R, Pasquali M. Bone resorption in syndromes of the Ras/MAPK pathway. Clin Genet 2011; 80:566-73. [PMID: 21204800 DOI: 10.1111/j.1399-0004.2010.01619.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Disorders of the Ras/mitogen-activated protein kinase (MAPK) pathway have an overlapping skeletal phenotype (e.g. scoliosis, osteopenia). The Ras proteins regulate cell proliferation and differentiation and neurofibromatosis type 1 (NF1) individuals have osteoclast hyperactivity and increased bone resorption as measured by urine pyridinium crosslinks [pyridinoline (Pyd) and deoxypyridinoline (Dpd)]. Pyd and Dpd are hydroxylysine-derived crosslinks of collagen found in bone and cartilage and excreted in the urine. Dpd is most abundant in bone. The aim of this study was to evaluate if other syndromes of the Ras/MAPK pathway have increased bone resorption, which may impact the skeletal phenotype. Participants were individuals with Noonan syndrome (n = 14), Costello syndrome (n = 21), and cardiofaciocutaneous (CFC) syndrome (n = 14). Pyridinium crosslinks from two consecutive first morning urines were extracted after acid hydrolysis and analyzed by high performance liquid chromatography. Three separate analyses of covariance were performed to compare Pyd, Dpd, and Dpd/Pyd ratio of each group to controls after controlling for age. Data were compared to 99 healthy controls. The Dpd and the Dpd/Pyd ratio were elevated (p < 0.0001) in all three conditions compared to controls suggesting that collagen degradation was predominantly from bone. The data suggest that the Ras/MAPK signal transduction pathway is important in bone homeostasis.
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Affiliation(s)
- D A Stevenson
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84132, USA.
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Abstract
BACKGROUND C-reactive protein (CRP) is a non-specific marker of inflammation that can be used for atherosclerotic risk assessment. This application requires increased precision at low CRP concentrations compared to traditional assays. METHODS The Micros CRP analyzer (ABX Diagnostics) is a small bench top device. Its limit of detection, limit of quantitation, linearity and imprecision were assessed. Method comparison studies were performed using samples both inside and outside the reference interval. Anticoagulant effects and the prozone effect were also evaluated. RESULTS The limit of detection was 0.1 mg/l. The method was linear from 2 to 60 and 0.3 to 60 mg/l using systematic error limits of 10% and 20%, respectively. The total imprecision was <8% for CRP concentrations from 0.7 to 9.1 mg/l. A prozone effect was seen at CRP concentrations >500 mg/l. Using samples from 120 apparently healthy adults, the Micros CRP method demonstrated excellent concordance with the BN II high sensitivity CRP (hs-CRP) method. The Micros CRP method compared well with a nephelometric method using samples with elevated CRP concentrations. CONCLUSIONS The Micros CRP method is adequate for atherosclerotic risk prediction in clinical practice but does not have adequate accuracy at CRP concentrations <2 mg/l for epidemiological studies.
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Affiliation(s)
- W L Roberts
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA.
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Starkweather WH, Spencer HH, Schwarz EL, Schoch HK. The electrophoretic separation of lactate dehydrogenase isoenzymes and their evaluation in clinical medicine. J Lab Clin Med 1966; 67:329-43. [PMID: 4285498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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