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Liu H, Sacks MS, Simonian NT, Gorman JH, Gorman RC. Simulated Effects of Acute Left Ventricular Myocardial Infarction on Mitral Regurgitation in an Ovine Model. J Biomech Eng 2024; 146:101009. [PMID: 38652602 PMCID: PMC11225881 DOI: 10.1115/1.4065376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 04/12/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Ischemic mitral regurgitation (IMR) occurs from incomplete coaptation of the mitral valve (MV) after myocardial infarction (MI), typically worsened by continued remodeling of the left ventricular (LV). The importance of LV remodeling is clear as IMR is induced by the post-MI dual mechanisms of mitral annular dilation and leaflet tethering from papillary muscle (PM) distension via the MV chordae tendineae (MVCT). However, the detailed etiology of IMR remains poorly understood, in large part due to the complex interactions of the MV and the post-MI LV remodeling processes. Given the patient-specific anatomical complexities of the IMR disease processes, simulation-based approaches represent an ideal approach to improve our understanding of this deadly disease. However, development of patient-specific models of left ventricle-mitral valve (LV-MV) interactions in IMR are complicated by the substantial variability and complexity of the MR etiology itself, making it difficult to extract underlying mechanisms from clinical data alone. To address these shortcomings, we developed a detailed ovine LV-MV finite element (FE) model based on extant comprehensive ovine experimental data. First, an extant ovine LV FE model (Sci. Rep. 2021 Jun 29;11(1):13466) was extended to incorporate the MV using a high fidelity ovine in vivo derived MV leaflet geometry. As it is not currently possible to image the MVCT in vivo, a functionally equivalent MVCT network was developed to create the final LV-MV model. Interestingly, in pilot studies, the MV leaflet strains did not agree well with known in vivo MV leaflet strain fields. We then incorporated previously reported MV leaflet prestrains (J. Biomech. Eng. 2023 Nov 1;145(11):111002) in the simulations. The resulting LV-MV model produced excellent agreement with the known in vivo ovine MV leaflet strains and deformed shapes in the normal state. We then simulated the effects of regional acute infarctions of varying sizes and anatomical locations by shutting down the local myocardial contractility. The remaining healthy (noninfarcted) myocardium mechanical behaviors were maintained, but allowed to adjust their active contractile patterns to maintain the prescribed pressure-volume loop behaviors in the acute post-MI state. For all cases studied, the LV-MV simulation demonstrated excellent agreement with known LV and MV in vivo strains and MV regurgitation orifice areas. Infarct location was shown to play a critical role in resultant MV leaflet strain fields. Specifically, extensional deformations of the posterior leaflets occurred in the posterobasal and laterobasal infarcts, while compressive deformations of the anterior leaflet were observed in the anterobasal infarct. Moreover, the simulated posterobasal infarct induced the largest MV regurgitation orifice area, consistent with experimental observations. The present study is the first detailed LV-MV simulation that reveals the important role of MV leaflet prestrain and functionally equivalent MVCT for accurate predictions of LV-MV interactions. Importantly, the current study further underscored simulation-based methods in understanding MV function as an integral part of the LV.
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Affiliation(s)
- Hao Liu
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, The Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, The Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Natalie T. Simonian
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, The Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, University of Pennsylvania, Philadelphia, PA 19146-2701
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, Smilow Center for Translational Research, University of Pennsylvania, Philadelphia, PA 19146-2701
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A total closed chest sheep model of cardiogenic shock by percutaneous intracoronary ethanol injection. Sci Rep 2020; 10:12417. [PMID: 32709984 PMCID: PMC7381645 DOI: 10.1038/s41598-020-68571-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022] Open
Abstract
To develop a reproducible and stable closed chest model of ischemic cardiogenic shock in sheep, with high survival rate and potential insight into human pathology. We established a protocol for multi-step myocardial alcoholisation of the left anterior descending coronary artery by percutaneous ethanol injection. A thorough hemodynamic assessment was obtained by invasive and non-invasive monitoring devices. Repeated blood samples were obtained to determine haemoglobin and alcohol concentration, electrolytes, blood gas parameters and cardiac troponin I. After sacrifice, tissue was excised for quantification of infarction and histology. Cardiogenic shock was characterized by a significant decrease in mean arterial pressure (− 33%), cardiac output (− 29%), dP/dtmax (− 28%), carotid blood flow (− 22%), left ventricular fractional shortening (− 28%), and left ventricle end-systolic pressure–volume relationship (− 51%). Lactate and cardiac troponin I levels increased from 1.4 ± 0.2 to 4.9 ± 0.7 mmol/L (p = 0.001) and from 0.05 ± 0.02 to 14.74 ± 2.59 µg/L (p = 0.001), respectively. All haemodynamic changes were stable over a three-hour period with a 71% survival rate. The necrotic volume (n = 5) represented 24.0 ± 1.9% of total ventricular mass. No sham exhibited any variation under general anaesthesia. We described and characterized, for the first time, a stable, reproducible sheep model of cardiogenic shock obtained by percutaneous intracoronary ethanol administration.
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Lindsey ML, Bolli R, Canty JM, Du XJ, Frangogiannis NG, Frantz S, Gourdie RG, Holmes JW, Jones SP, Kloner RA, Lefer DJ, Liao R, Murphy E, Ping P, Przyklenk K, Recchia FA, Schwartz Longacre L, Ripplinger CM, Van Eyk JE, Heusch G. Guidelines for experimental models of myocardial ischemia and infarction. Am J Physiol Heart Circ Physiol 2018; 314:H812-H838. [PMID: 29351451 PMCID: PMC5966768 DOI: 10.1152/ajpheart.00335.2017] [Citation(s) in RCA: 347] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Myocardial infarction is a prevalent major cardiovascular event that arises from myocardial ischemia with or without reperfusion, and basic and translational research is needed to better understand its underlying mechanisms and consequences for cardiac structure and function. Ischemia underlies a broad range of clinical scenarios ranging from angina to hibernation to permanent occlusion, and while reperfusion is mandatory for salvage from ischemic injury, reperfusion also inflicts injury on its own. In this consensus statement, we present recommendations for animal models of myocardial ischemia and infarction. With increasing awareness of the need for rigor and reproducibility in designing and performing scientific research to ensure validation of results, the goal of this review is to provide best practice information regarding myocardial ischemia-reperfusion and infarction models. Listen to this article’s corresponding podcast at ajpheart.podbean.com/e/guidelines-for-experimental-models-of-myocardial-ischemia-and-infarction/.
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Affiliation(s)
- Merry L Lindsey
- Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi.,Research Service, G. V. (Sonny) Montgomery Veterans Affairs Medical Center , Jackson, Mississippi
| | - Roberto Bolli
- Division of Cardiovascular Medicine and Institute of Molecular Cardiology, University of Louisville , Louisville, Kentucky
| | - John M Canty
- Division of Cardiovascular Medicine, Departments of Biomedical Engineering and Physiology and Biophysics, The Veterans Affairs Western New York Health Care System and Clinical and Translational Science Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo , Buffalo, New York
| | - Xiao-Jun Du
- Baker Heart and Diabetes Institute , Melbourne, Victoria , Australia
| | - Nikolaos G Frangogiannis
- The Wilf Family Cardiovascular Research Institute, Department of Medicine (Cardiology), Albert Einstein College of Medicine, Bronx, New York
| | - Stefan Frantz
- Department of Internal Medicine I, University Hospital , Würzburg , Germany
| | - Robert G Gourdie
- Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute , Roanoke, Virginia
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia Health System , Charlottesville, Virginia
| | - Steven P Jones
- Department of Medicine, Institute of Molecular Cardiology, Diabetes and Obesity Center, University of Louisville , Louisville, Kentucky
| | - Robert A Kloner
- HMRI Cardiovascular Research Institute, Huntington Medical Research Institutes , Pasadena, California.,Division of Cardiovascular Medicine, Keck School of Medicine, University of Southern California , Los Angeles, California
| | - David J Lefer
- Cardiovascular Center of Excellence, Louisiana State University Health Science Center , New Orleans, Louisiana
| | - Ronglih Liao
- Harvard Medical School , Boston, Massachusetts.,Division of Genetics and Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital , Boston, Massachusetts
| | - Elizabeth Murphy
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Peipei Ping
- National Institutes of Health BD2KBig Data to Knowledge (BD2K) Center of Excellence and Department of Physiology, Medicine and Bioinformatics, University of California , Los Angeles, California
| | - Karin Przyklenk
- Cardiovascular Research Institute and Departments of Physiology and Emergency Medicine, Wayne State University School of Medicine , Detroit, Michigan
| | - Fabio A Recchia
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Fondazione G. Monasterio, Pisa , Italy.,Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - Lisa Schwartz Longacre
- Heart Failure and Arrhythmias Branch, Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Crystal M Ripplinger
- Department of Pharmacology, School of Medicine, University of California , Davis, California
| | - Jennifer E Van Eyk
- The Smidt Heart Institute, Department of Medicine, Cedars Sinai Medical Center , Los Angeles, California
| | - Gerd Heusch
- Institute for Pathophysiology, West German Heart and Vascular Center, University of Essen Medical School , Essen , Germany
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Romito E, Shazly T, Spinale FG. In vivo assessment of regional mechanics post-myocardial infarction: A focus on the road ahead. J Appl Physiol (1985) 2017; 123:728-745. [PMID: 28235858 DOI: 10.1152/japplphysiol.00589.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 01/13/2017] [Accepted: 02/18/2017] [Indexed: 12/21/2022] Open
Abstract
Cardiovascular disease, particularly the occurrence of myocardial infarction (MI), remains a leading cause of morbidity and mortality (Go et al., Circulation 127: e6-e245, 2013; Go et al. Circulation 129: e28-e292, 2014). There is growing recognition that a key factor for post-MI outcomes is adverse remodeling and changes in the regional structure, composition, and mechanical properties of the MI region itself. However, in vivo assessment of regional mechanics post-MI can be confounded by the species, temporal aspects of MI healing, as well as size, location, and extent of infarction across myocardial wall. Moreover, MI regional mechanics have been assessed over varying phases of the cardiac cycle, and thus, uniform conclusions regarding the material properties of the MI region can be difficult. This review assesses past studies that have performed in vivo measures of MI mechanics and attempts to provide coalescence on key points from these studies, as well as offer potential recommendations for unifying approaches in terms of regional post-MI mechanics. A uniform approach to biophysical measures of import will allow comparisons across studies, as well as provide a basis for potential therapeutic markers.
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Affiliation(s)
- Eva Romito
- University of South Carolina School of Engineering and Computing, Columbia, South Carolina; .,Cardiovascular Translational Research Center, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Tarek Shazly
- University of South Carolina School of Engineering and Computing, Columbia, South Carolina
| | - Francis G Spinale
- University of South Carolina School of Engineering and Computing, Columbia, South Carolina.,Cardiovascular Translational Research Center, University of South Carolina School of Medicine, Columbia, South Carolina.,Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina; and.,William Jennings Bryan Dorn Veteran Affairs Medical Center, Columbia, South Carolina
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Baumert JH, Roehl AB, Funcke S, Hein M. Xenon protects left ventricular diastolic function during acute ischemia, less than ischemic preconditioning. Med Gas Res 2016; 6:130-137. [PMID: 27867480 PMCID: PMC5110144 DOI: 10.4103/2045-9912.191358] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Anesthetics modify regional left ventricular (LV) dysfunction following ischemia/reperfusion but their effects on global function in this setting are less clear. Aim of this study was to test the hypothesis that xenon would limit global LV dysfunction as caused by acute anterior wall ischemia, comparable to ischemic preconditioning. In an open-chest model under thiopental anesthesia, 30 pigs underwent 60-minute left anterior descending coronary artery occlusion, followed by 120 minutes of reperfusion. A xenon group (constant inhalation from previous to ischemia through end of reperfusion) was compared to control and ischemic preconditioning. Load-independent measures of diastolic function (end-diastolic pressure-volume relation, time constant of relaxation) and systolic function (end-systolic pressure-volume relation, preload-recruitable stroke work) were determined. Heart rate, arterial pressure, cardiac output, and arterial elastance were recorded. Data were compared in 26 pigs. Ischemia impaired global diastolic but not systolic function in control, which recovered during reperfusion. Xenon limited and preconditioning abolished diastolic dysfunction during ischemia. Arterial pressure decreased during reperfusion while arterial elastance increased. Tachycardia and antero-septal wall edema during reperfusion were observed in all groups. In spite of ischemia of 40% of LV mass, global systolic function was preserved. Deterioration in global diastolic function was limited by xenon and prevented by preconditioning.
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Affiliation(s)
- Jan-H Baumert
- Department of Anesthesiology, Intensive Care and Pain Medicine, KRH Klinikum Nordstadt, Hannover, Germany
| | - Anna B Roehl
- Department of Anesthesiology, University Hospital Aachen, Aachen, Germany
| | - Sandra Funcke
- Department of Anesthesiology, University Hospital Aachen, Aachen, Germany
| | - Marc Hein
- Department of Anesthesiology, University Hospital Aachen, Aachen, Germany
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Optimized local infarct restraint improves left ventricular function and limits remodeling. Ann Thorac Surg 2012; 95:155-62. [PMID: 23146279 DOI: 10.1016/j.athoracsur.2012.08.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/14/2012] [Accepted: 08/21/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND Preventing expansion and dyskinetic movement of a myocardial infarction (MI) can limit left ventricular (LV) remodeling. Using a device designed to produce variable alteration of infarct stiffness and geometry, we sought to understand how these parameters affect LV function and remodeling early after MI. METHODS Ten pigs had posterolateral infarctions. An unexpanded device was placed in 5 animals at the time of infarction and 5 animals served as untreated controls. One week after MI animals underwent magnetic resonance imaging to assess LV size and regional function. In the treatment group, after initial imaging, the device was expanded with 2, 4, 6, 8, and 10 mL of saline. The optimal degree of inflation was defined as that which maximized stroke volume (SV). The device was left optimally inflated in the treatment animals for 3 additional weeks. RESULTS One week after MI, device inflation to 6 mL or greater significantly (p < 0.05) decreased end-systolic volume (0 mL, 59.9 mL ± 3.8; 6 mL, 54.0 mL ± 3.1; 8 mL, 50.5 mL ± 4.8; and 10 mL, 46.1 mL ± 2.2) and increased ejection fraction (EF) (0 mL, 0.346 ± 0.016; 6 mL, 0.0397 ± 0.009; 8 mL, 0.431 ± 0.027; and 10 mL, 0.441 ± 0.009). Systolic volume significantly (p < 0.05) improved for the 6 mL and 8 mL volumes (0 mL, 31.2 mL ± 2.6; 6 mL, 35.7 mL ± 2.0; and 8 mL, 37.5 mL ± 1.9) but trended downward for 10 mL (36.6 mL ± 2.8). At 4 weeks after MI, end-diastolic volume and end-systolic volume were unchanged from 1-week values in the treatment group while the control group continued to dilate. Systolic volume (38.2 ± 4.4 mL vs 34.0.1 ± 4.8 mL, p = 0.08) and EF (0.360 ± 0.026 vs 0.276 ± 0.014, p = 0.04) were also better in the treatment animals. CONCLUSIONS Optimized isolated infarct restraint can limit adverse LV remodeling after MI. The tested device affords the potential for a patient-specific therapy to preserve cardiac function after MI.
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Induction of cardiomyocyte apoptosis by anti-cardiac myosin heavy chain antibodies in patients with acute myocardial infarction. ACTA ACUST UNITED AC 2010; 30:582-8. [DOI: 10.1007/s11596-010-0546-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Indexed: 12/13/2022]
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Hamamoto H, Sakamoto H, Leshnower BG, Parish LM, Kanemoto S, Hinmon R, Plappert T, Miyamoto S, St John-Sutton MG, Gorman JH, Gorman RC. Very mild hypothermia during ischemia and reperfusion improves postinfarction ventricular remodeling. Ann Thorac Surg 2009; 87:172-7. [PMID: 19101292 DOI: 10.1016/j.athoracsur.2008.08.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 08/04/2008] [Accepted: 08/06/2008] [Indexed: 11/26/2022]
Abstract
BACKGROUND Mild hypothermia (< 4 degrees C) improves myocardial salvage after infarct reperfusion in animals and in early clinical studies. In this experiment the effect of mild hypothermia during ischemia and early reperfusion on long-term postinfarction left ventricular (LV) remodeling was assessed in an ovine infarct model. METHODS In the initial phase of the experiment the effect of progressive degrees of hypothermia on infarct size was quantified. Thirty-eight male sheep were subjected to 1 hour of ischemia using a standardized anteroapical infarct followed by 3 hours of reperfusion. Temperature was maintained at either 39.5 degrees C (n = 11), 38.5 degrees C (n = 7), 37.5 degrees C (n = 7), 36.5 degrees C (n = 7), or 35.5 degrees C (n = 6) for the entire period of ischemia and reperfusion. The area at risk (AR) and infarct size as a percentage of AR (I/AR) were determined with a double staining and planimetry technique. In the second phase of the study, chronic post-infarction remodeling was assessed in animals with nonreperfused infarcts (n = 6), 1 hour of ischemia followed by reperfusion at 39.5 degrees C (n = 6) and 1 hour of ischemia followed by reperfusion at 37.5 degrees C (n = 6). Remodeling was determined at 8 weeks after infarction using echocardiography. RESULTS The I/AR in the 39.5 degrees C, 38.5 degrees C, 37.5 degrees C, 36.5 degrees C, and the 35.5 degrees C groups was 71.8 +/- 3.0%, 63.1 +/- 1.9%, 49.4 +/- 1.4%, 38.7 +/- 1.4%, and 21.7 +/- 2.2%, respectively (p < 0.05 between all groups). In the chronic study LV end systolic volume at 8 weeks after infarction was 81 +/- 8 mL in the nonreperfused group, 57 +/- 4 mL in the 39.5 degrees C reperfusion group, and 41 +/- 3 mL in the 37.5 degrees C reperfusion group (p < 0.05 for between group differences). CONCLUSIONS Subtle degrees of hypothermia can significantly improve immediate myocardial salvage and long-term LV remodeling after infarct reperfusion.
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Affiliation(s)
- Hirotsugu Hamamoto
- Harrison Department of Surgical Research, Glenolden Research Laboratory, Glenolden, Pennsylvania 19036, USA
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Invited commentary. Ann Thorac Surg 2007; 84:1536-7. [DOI: 10.1016/j.athoracsur.2007.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 06/04/2007] [Accepted: 06/11/2007] [Indexed: 11/17/2022]
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