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Mori T, Matsushita S, Morita T, Abudurezake A, Mochizuki J, Amano A. Evaluation of mitral chordae tendineae length using four-dimensional computed tomography. World J Cardiol 2024; 16:274-281. [PMID: 38817650 PMCID: PMC11135327 DOI: 10.4330/wjc.v16.i5.274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/16/2024] [Accepted: 04/16/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND Mitral valvuloplasty using artificial chordae tendineae represents an effective surgical approach for treating mitral regurgitation. Achieving precise measurements of artificial chordae tendineae length (CL) is an important factor in the procedure; however, no objective index currently exists to facilitate this measurement. Therefore, preoperative assessment of CL is critical for surgical planning and support. Four-dimensional x-ray micro-computed tomography (4D-CT) may be useful for accurate CL measurement considering that it allows for dynamic three-dimensional (3D) evaluation compared to that with transthoracic echocardiography, a conventional inspection method. AIM To investigate the behavior and length of mitral chordae tendineae during systole using 4D-CT. METHODS Eleven adults aged > 70 years without mitral valve disease were evaluated. A 64-slice CT scanner was used to capture 20 phases in the cardiac cycle in electrocardiographic synchronization. The length of the primary chordae tendineae was measured from early systole to early diastole using the 3D image. The primary chordae tendineae originating from the anterior papillary muscle and attached to the A1-2 region and those from the posterior papillary muscle and attached to the A2-3 region were designated as cA and cP, respectively. The behavior and maximum lengths [cA (ma), cP (max)] were compared, and the correlation with body surface area (BSA) was evaluated. RESULTS In all cases, the mitral anterior leaflet chordae tendineae could be measured. In most cases, the cA and cP chordae tendineae could be measured visually. The mean cA (max) and cP (max) were 20.2 mm ± 1.95 mm and 23.5 mm ± 4.06 mm, respectively. cP (max) was significantly longer. The correlation coefficients (r) with BSA were 0.60 and 0.78 for cA (max) and cP (max), respectively. Both cA and cP exhibited constant variation in CL during systole, with a maximum 1.16-fold increase in cA and a 1.23-fold increase in cP from early to mid-systole. For cP, CL reached a plateau at 15% and remained elongated until end-systole, whereas for cA, after peaking at 15%, CL shortened slightly and then moved toward its peak again as end-systole approached. CONCLUSION The study suggests that 4D-CT is a valuable tool for accurate measurement of both the length and behavior of chordae tendineae within the anterior leaflet of the mitral valve.
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Affiliation(s)
- Takuya Mori
- Department of Cardiovascular Surgery, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan
- Department of Cardiovascular Surgery, JACCT Japan Animal Cardiovascular Care Team, Osaka 533-0033, Japan
| | - Satoshi Matsushita
- Department of Cardiovascular Surgery, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan.
| | - Terumasa Morita
- Department of Cardiovascular Surgery, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan
| | - Abulaiti Abudurezake
- Department of Cardiovascular Surgery, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan
| | - Junji Mochizuki
- Department of Radiology, Minamino Cardiovascular Hospital, Tokyo 192-0918, Japan
| | - Atsushi Amano
- Department of Cardiovascular Surgery, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan
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2
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Kim DH. Multimodality Imaging for the Assessment of Mitral Valve Disease. Interv Cardiol Clin 2024; 13:115-125. [PMID: 37980062 DOI: 10.1016/j.iccl.2023.09.005] [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] [Indexed: 11/20/2023]
Abstract
Mitral valve disease is the most common valvular heart disease. Imaging determines the etiology (anatomic assessment), valve function and severity of valvular heart disease (hemodynamic assessment), remodeling of the left ventricle and right ventricle, and preplanning and guidance of percutaneous intervention. Although roles of computed tomography and magnetic resonance are increasing, echocardiography serves as the first-line imaging modality for the diagnosis and serial follow-up in most cases. This review summarizes the roles of multimodality imaging currently available from research fields to daily clinical practice.
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Affiliation(s)
- Dae-Hee Kim
- Division of Cardiology, Asan Medical Center, College of Medicine, University of Ulsan, 388-1, Poongnap-dong, Songpa-ku, Seoul 138-736, Korea.
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3
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Alexis M, Laurence F, Marie-Aude G, Christian L, Nicolas B. Comparative anatomy of the mitral valve in four species (human, ovine, porcine and canine): A pre-clinical perspective. Anat Histol Embryol 2023; 52:927-935. [PMID: 37485820 DOI: 10.1111/ahe.12952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/09/2023] [Indexed: 07/25/2023]
Abstract
This study aimed to provide comparative anatomical data on the mitral valve and to substantiate the choice between large species for pre-clinical testing of cardiac devices. Different anatomical parameters of the anterior and posterior leaflets, chordae and papillary muscles were measured to characterize the anatomy of the mitral valve in 10 individuals for each four species. Ratios were calculated and used to circumvent the interspecies variations of body and heart size and weight. The results underline many relevant anatomical similarities and differences between man and the three animal species. We confirm that the porcine species is a better model based on anatomical measurements. But many parameters should be considered depending on the shape, size and purpose of the device. The mitral and aortic valve are closer than in man leading to potential damage of the aortic valve by a mitral device. The ovine mitral annulus is more flattened and would sustain more mechanical forces on a round-shaped stent. The anterior and posterior leaflets have comparable height in the animal species leading to more space for implantation. The porcine valve has more chordae allowing less space around the valve for a transcatheter stent. Our observations introduce new comparative data in the perspective of the choice of a large animal model for pre-clinical testing of mitral devices. They are very helpful for all cardiologists, surgeons or engineers who need to understand the reasons for success or failure of a device and to have key elements of discussion.
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de Oliveira DC, Espino DM, Deorsola L, Buchan K, Dawson D, Shepherd DET. A geometry-based finite element tool for evaluating mitral valve biomechanics. Med Eng Phys 2023; 121:104067. [PMID: 37985031 DOI: 10.1016/j.medengphy.2023.104067] [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: 03/15/2023] [Revised: 09/08/2023] [Accepted: 10/30/2023] [Indexed: 11/22/2023]
Abstract
Mitral valve function depends on its complex geometry and tissue health, with alterations in shape and tissue response affecting the long-term restorarion of function. Previous computational frameworks for biomechanical assessment are mostly based on patient-specific geometries; however, these are not flexible enough to yield a variety of models and assess mitral closure for individually tuned morphological parameters or material property representations. This study details the finite element approach implemented in our previously developed toolbox to assess mitral valve biomechanics and showcases its flexibility through the generation and biomechanical evaluation of different models. A healthy valve geometry was generated and its computational predictions for biomechanics validated against data in the literature. Moreover, two mitral valve models including geometric alterations associated with disease were generated and analysed. The healthy mitral valve model yielded biomechanical predictions in terms of valve closure dynamics, leaflet stresses and papillary muscle and chordae forces comparable to previous computational and experimental studies. Mitral valve function was compromised in geometries representing disease, expressed by the presence of regurgitating areas, elevated stress on the leaflets and unbalanced subvalvular apparatus forces. This showcases the flexibility of the toolbox concerning the generation of a range of mitral valve models with varying geometric definitions and material properties and the evaluation of their biomechanics.
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Affiliation(s)
- Diana C de Oliveira
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; Current affiliation: Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom.
| | - Daniel M Espino
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Luca Deorsola
- Paedriatic Cardiac Surgery, Ospedale Infantile Regina Margherita Sant Anna, Turin 10126, Italy
| | - Keith Buchan
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen AB24 2ZN, Scotland, UK
| | - Dana Dawson
- School of Medicine, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK; Cardiology Department, Aberdeen Royal Infirmary, Aberdeen AB25 2ZN, Scotland, UK
| | - Duncan E T Shepherd
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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5
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Liu H, Simonian NT, Pouch AM, Iaizzo PA, Gorman JH, Gorman RC, Sacks MS. A Computational Pipeline for Patient-Specific Prediction of the Postoperative Mitral Valve Functional State. J Biomech Eng 2023; 145:111002. [PMID: 37382900 PMCID: PMC10405284 DOI: 10.1115/1.4062849] [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: 02/24/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 06/30/2023]
Abstract
While mitral valve (MV) repair remains the preferred clinical option for mitral regurgitation (MR) treatment, long-term outcomes remain suboptimal and difficult to predict. Furthermore, pre-operative optimization is complicated by the heterogeneity of MR presentations and the multiplicity of potential repair configurations. In the present work, we established a patient-specific MV computational pipeline based strictly on standard-of-care pre-operative imaging data to quantitatively predict the post-repair MV functional state. First, we established human mitral valve chordae tendinae (MVCT) geometric characteristics obtained from five CT-imaged excised human hearts. From these data, we developed a finite-element model of the full patient-specific MV apparatus that included MVCT papillary muscle origins obtained from both the in vitro study and the pre-operative three-dimensional echocardiography images. To functionally tune the patient-specific MV mechanical behavior, we simulated pre-operative MV closure and iteratively updated the leaflet and MVCT prestrains to minimize the mismatch between the simulated and target end-systolic geometries. Using the resultant fully calibrated MV model, we simulated undersized ring annuloplasty (URA) by defining the annular geometry directly from the ring geometry. In three human cases, the postoperative geometries were predicted to 1 mm of the target, and the MV leaflet strain fields demonstrated close agreement with noninvasive strain estimation technique targets. Interestingly, our model predicted increased posterior leaflet tethering after URA in two recurrent patients, which is the likely driver of long-term MV repair failure. In summary, the present pipeline was able to predict postoperative outcomes from pre-operative clinical data alone. This approach can thus lay the foundation for optimal tailored surgical planning for more durable repair, as well as development of mitral valve digital twins.
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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, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712-1229
| | - Natalie T. Simonian
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712-1229
| | - Alison M. Pouch
- Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Paul A. Iaizzo
- Visible Heart Laboratories, Department of Surgery, University of Minnesota, Minneapolis, MN 55455
| | - Joseph H. Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Robert C. Gorman
- Gorman Cardiovascular Research Group, Department of Surgery, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Michael S. Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712-1229
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van Kampen A, Morningstar JE, Goudot G, Ingels N, Wenk JF, Nagata Y, Yaghoubian KM, Norris RA, Borger MA, Melnitchouk S, Levine RA, Jensen MO. Utilization of Engineering Advances for Detailed Biomechanical Characterization of the Mitral-Ventricular Relationship to Optimize Repair Strategies: A Comprehensive Review. Bioengineering (Basel) 2023; 10:601. [PMID: 37237671 PMCID: PMC10215167 DOI: 10.3390/bioengineering10050601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
The geometrical details and biomechanical relationships of the mitral valve-left ventricular apparatus are very complex and have posed as an area of research interest for decades. These characteristics play a major role in identifying and perfecting the optimal approaches to treat diseases of this system when the restoration of biomechanical and mechano-biological conditions becomes the main target. Over the years, engineering approaches have helped to revolutionize the field in this regard. Furthermore, advanced modelling modalities have contributed greatly to the development of novel devices and less invasive strategies. This article provides an overview and narrative of the evolution of mitral valve therapy with special focus on two diseases frequently encountered by cardiac surgeons and interventional cardiologists: ischemic and degenerative mitral regurgitation.
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Affiliation(s)
- Antonia van Kampen
- Division of Cardiac Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Leipzig Heart Centre, University Clinic of Cardiac Surgery, 02189 Leipzig, Germany
| | - Jordan E. Morningstar
- Department of Regenerative Medicine and Cell Biology, University of South Carolina, Charleston, SC 29425, USA
| | - Guillaume Goudot
- Cardiac Ultrasound Laboratory, Department of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Neil Ingels
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
| | - Jonathan F. Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40508, USA;
| | - Yasufumi Nagata
- Cardiac Ultrasound Laboratory, Department of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Koushiar M. Yaghoubian
- Division of Cardiac Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Russell A. Norris
- Department of Regenerative Medicine and Cell Biology, University of South Carolina, Charleston, SC 29425, USA
| | - Michael A. Borger
- Leipzig Heart Centre, University Clinic of Cardiac Surgery, 02189 Leipzig, Germany
| | - Serguei Melnitchouk
- Division of Cardiac Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Robert A. Levine
- Cardiac Ultrasound Laboratory, Department of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Morten O. Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Barry M, Gun M, Hun-Chabry Y, Harmouche M, Peltier J, Caus T, Havet E. Anatomical and biometric study of the mitral valve apparatus: application in valve repair surgery. J Cardiothorac Surg 2023; 18:141. [PMID: 37060017 PMCID: PMC10105398 DOI: 10.1186/s13019-023-02232-2] [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: 11/08/2022] [Accepted: 04/02/2023] [Indexed: 04/16/2023] Open
Abstract
OBJECTIVE Most mitral valve repair techniques provide excellent surgical results by removing regurgitation, but all of these techniques simultaneously reduce posterior valve mobility. A comprehensive biometric study of the mitral valve apparatus will provide landmarks that would help improve this posterior valve mobility. MATERIALS AND METHODS Thirty one (31) human hearts have been studied, from 14 women and 17 men. The characteristics of the studied sample were analyzed descriptively. The difference in means of the variables between women and men were tested using a Student t test. Correlations between the different measures were determined by simple regression analysis. Mean values are shown with ± 1 standard deviation and the limit of significance was set at 0.05. RESULTS The mean weight of the hearts was 275.3 ± 2.4 g. The anteroposterior diameter of the mitral annulus was 29.3 ± 1.22 mm, the intertrigonal distance was 25.2 ± 3.50 mm and the anterior leaflet to posterior leaflet ratio was 1.9 ± 0.10, the length of the chordae A2 = 19.4 ± 1.15 mm and P2 = 14.5 ± 0.85 mm. The length of the anterior papillary muscle averaged 30.9 ± 7.20 mm and that of the posterior one 30.0 ± 8.75 mm. The comparison of the different values measured between women and men showed no statistically significant difference (p > 0.05). There was no correlation between these different measured values (p > 0.05). CONCLUSION A perfect knowledge of anatomy and biometry is therefore essential to offer alternative techniques that reproduce the real anatomy and physiology with a complete reconstruction of the mitral valve.
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Affiliation(s)
- Misbaou Barry
- Laboratory of Anatomy, Faculty of Medicine, University of Picardie-Jule Vernes, Amiens, France.
- Department of Cardiac Surgery, Amiens Picardie University Hospital Center, 1 Rue du Professeur Christian CABROL, 80054, Amiens Cedex1, France.
| | - Mesut Gun
- Department of Cardiology, Amiens Picardie University Hospital Center, 1 Rue du Professeur Christian CABROL, 80054, Amiens Cedex 1, France
| | - Yuthiline Hun-Chabry
- Department of Cardiac Surgery, Amiens Picardie University Hospital Center, 1 Rue du Professeur Christian CABROL, 80054, Amiens Cedex1, France
| | - Majid Harmouche
- Department of Cardiac Surgery, Amiens Picardie University Hospital Center, 1 Rue du Professeur Christian CABROL, 80054, Amiens Cedex1, France
| | - Johann Peltier
- Laboratory of Anatomy, Faculty of Medicine, University of Picardie-Jule Vernes, Amiens, France
| | - Thierry Caus
- Department of Cardiac Surgery, Amiens Picardie University Hospital Center, 1 Rue du Professeur Christian CABROL, 80054, Amiens Cedex1, France
| | - Eric Havet
- Laboratory of Anatomy, Faculty of Medicine, University of Picardie-Jule Vernes, Amiens, France
- Department of Radiology, Amiens Picardie University Hospital Center, 1 Rue du Professeur Christian CABROL, 80054, Amiens Cedex 1, France
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Leković A, Živković V, Nikolić S. Anomalous papillary muscle insertion into mitral valve leaflet: Autopsy study and implications. J Forensic Sci 2023; 68:176-184. [PMID: 36480239 DOI: 10.1111/1556-4029.15182] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
Anomalous papillary muscle (APM) insertion into the anterior mitral valve leaflet is often associated with hypertrophic cardiomyopathy (HCM) but is reported in other cases as a rare finding. Mere presence does not strictly imply hemodynamic disturbance, and several types exist, with various impacts on left ventricular outflow tract (LVOT) obstruction. The interpretation of isolated anomaly is challenging at autopsy because significant LVOT obstruction is dynamic. We analyzed autopsy cases with APM regarding the site of PM insertion and origin, number of PM bellies, anomalous insertions, heart weight, left ventricle (LV) thickness, LV endocardial fibrosis, subjects' age, sex, cause, and manner of death. A total of 20 cases were identified. Fourteen were identified incidentally, while in 670 systematically examined hearts, the APM was identified in six cases, indicating a prevalence of 0.9%. In eight cases, the manner of death was natural (one case with HCM), and in 12 non-natural. Type II anomaly of PM was most frequent (n = 8), followed by Type III (n = 7) and Type I (n = 5). Subjects who died of natural causes were significantly older and had heavier hearts (median 455 g vs. 330 g; p < 0.05) without difference in LV thickness (median 16 mm vs. 15 mm; p > 0.05). Histology performed in four cases showed a pattern of direct insertion of cardiomyocytes into the leaflet's thick fibrous tissue with a narrow overlapping zone. The APM is rare, can be easily overlooked, and does not imply significant pathology per se. We discussed proper assessment of the significance of this anomaly at autopsy.
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Affiliation(s)
- Aleksa Leković
- Institute of Forensic Medicine, University of Belgrade - School of Medicine, Belgrade, Serbia
| | - Vladimir Živković
- Institute of Forensic Medicine, University of Belgrade - School of Medicine, Belgrade, Serbia
| | - Slobodan Nikolić
- Institute of Forensic Medicine, University of Belgrade - School of Medicine, Belgrade, Serbia
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9
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Secondary Mitral Regurgitation: Cardiac Remodeling, Diagnosis, and Management. STRUCTURAL HEART 2022. [DOI: 10.1016/j.shj.2022.100129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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10
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Ferreño D, Revuelta JM, Sainz-Aja JA, Wert-Carvajal C, Casado JA, Diego S, Carrascal IA, Silva J, Gutiérrez-Solana F. Shannon entropy as a reliable score to diagnose human fibroelastic degenerative mitral chords: A micro-ct ex-vivo study. Med Eng Phys 2022; 110:103919. [PMID: 36564142 DOI: 10.1016/j.medengphy.2022.103919] [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: 03/14/2022] [Revised: 09/12/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022]
Abstract
This paper is aimed at identifying by means of micro-CT the microstructural differences between normal and degenerative mitral marginal chordae tendineae. The control group is composed of 21 normal chords excised from 14 normal mitral valves from heart transplant recipients. The experimental group comprises 22 degenerative fibroelastic chords obtained at surgery from 11 pathological valves after mitral repair or replacement. In the control group the superficial endothelial cells and spongiosa layer remained intact, covering the wavy core collagen. In contrast, in the experimental group the collagen fibers were arranged as straightened thick bundles in a parallel configuration. 100 cross-sections were examined by micro-CT from each chord. Each image was randomized through the K-means machine learning algorithm and then, the global and local Shannon entropies were obtained. The optimum number of clusters, K, was estimated to maximize the differences between normal and degenerative chords in global and local Shannon entropy; the p-value after a nested ANOVA test was chosen as the parameter to be minimized. Optimum results were obtained with global Shannon entropy and 2≤K≤7, providing p < 0.01; for K=3, p = 2.86·10-3. These findings open the door to novel perioperative diagnostic methods in order to avoid or reduce postoperative mitral valve regurgitation recurrences.
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Affiliation(s)
- Diego Ferreño
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain.
| | - José M Revuelta
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain; Cardiovascular Surgery. Hospital Universitario Marqués de Valdecilla, Av/Valdecilla, s/n, 39008 Santander, Spain
| | - José A Sainz-Aja
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain
| | - Carlos Wert-Carvajal
- Universidad Carlos III de Madrid. Avda. de la Universidad, 30. 28911 Madrid, Spain; University of California, San Diego. 9500 Gilman Drive, MC 0412 La Jolla, California
| | - José A Casado
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain
| | - Soraya Diego
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain
| | - Isidro A Carrascal
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain
| | - Jacobo Silva
- Hospital Universitario Central de Asturias, Av. Roma, s/n, 33011 Oviedo, Asturias, Spain
| | - Federico Gutiérrez-Solana
- LADICIM (Laboratory of Materials Science and Engineering), University of Cantabria. E.T.S. de Ingenieros de Caminos, Canales y Puertos, Av/Los Castros 44, 39005 Santander, Spain
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Wang B, Sierad LN, Mercuri JJ, Simionescu A, Simionescu DT, Williams LN, Vela R, Bajona P, Peltz M, Ramaswamy S, Hong Y, Liao J. Structural and biomechanical characterizations of acellular porcine mitral valve scaffolds: anterior leaflets, posterior leaflets, and chordae tendineae. ENGINEERED REGENERATION 2022; 3:374-386. [PMID: 38362305 PMCID: PMC10869114 DOI: 10.1016/j.engreg.2022.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Mitral valve (MV) tissue engineering is still in its early stage, and one major challenge in MV tissue engineering is to identify appropriate scaffold materials. With the potential of acellular MV scaffolds being demonstrated recently, it is important to have a full understanding of the biomechanics of the native MV components and their acellular scaffolds. In this study, we have successfully characterized the structural and mechanical properties of porcine MV components, including anterior leaflet (AL), posterior leaflet (PL), strut chordae, and basal chordae, before and after decellularization. Quantitative DNA assay showed more than 90% reduction in DNA content, and Griffonia simplicifolia (GS) lectin immunohistochemistry confirmed the complete lack of porcine α-Gal antigen in the acellular MV components. In the acellular AL and PL, the atrialis, spongiosa, and fibrosa trilayered structure, along with its ECM constitutes, i.e., collagen fibers, elastin fibers, and portion of GAGs, were preserved. Nevertheless, the ECM of both AL and PL experienced a certain degree of disruption, exhibiting a less dense, porous ECM morphology. The overall anatomical morphology of the strut and basal chordae were also maintained after decellularization, with longitudinal morphology experiencing minimum disruption, but the cross-sectional morphology exhibiting evenly-distributed porous structure. In the acellular AL and PL, the nonlinear anisotropic biaxial mechanical behavior was overall preserved; however, uniaxial tensile tests showed that the removal of cellular content and the disruption of structural ECM did result in small decreases in maximum tensile modulus, tissue extensibility, failure stress, and failure strain for both MV leaflets and chordae.
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Affiliation(s)
- Bo Wang
- Joint Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI 53226, United States
| | - Leslie N. Sierad
- Department of Bioengineering, Clemson University, Clemson, SC 29634, United States
| | - Jeremy J. Mercuri
- Department of Bioengineering, Clemson University, Clemson, SC 29634, United States
| | - Agneta Simionescu
- Department of Bioengineering, Clemson University, Clemson, SC 29634, United States
| | - Dan T. Simionescu
- Department of Bioengineering, Clemson University, Clemson, SC 29634, United States
| | - Lakiesha N. Williams
- Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, United States
| | - Ryan Vela
- Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Pietro Bajona
- Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
- Allegheny Health Network-Drexel University College of Medicine, Pittsburgh, PA 15212, United States
| | - Matthias Peltz
- Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Sharan Ramaswamy
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, United States
| | - Yi Hong
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76010, United States
| | - Jun Liao
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76010, United States
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12
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Nakagawa Y, Furusho H, Miwa K, Yasuda T. A case of premature ventricular contraction originating at the aortomitral fibrous continuity and exiting from the anterolateral papillary muscle due to muscular chordae tendineae. HeartRhythm Case Rep 2022; 9:38-42. [PMID: 36685677 PMCID: PMC9845550 DOI: 10.1016/j.hrcr.2022.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Yoichiro Nakagawa
- Address reprint requests and correspondence: Dr Yoichiro Nakagawa, Department of Cardiology, Ishikawa Prefectural Central Hospital, 2-1 Kuratsuki Higashi, Kanazawa City, Ishikawa Prefecture, Japan 920-8530.
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13
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Park MH, Imbrie-Moore AM, Zhu Y, Sellke M, Marin-Cuartas M, Wilkerson R, Woo YJ. A Novel Accelerated Fatigue Testing System for Pulsatile Applications of Cardiac Devices Using Widely Translatable Cam and Linkage-Based Mechanisms. Med Eng Phys 2022; 109:103896. [DOI: 10.1016/j.medengphy.2022.103896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/02/2022] [Accepted: 09/21/2022] [Indexed: 10/14/2022]
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14
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Demonstration of Use of a Novel 3D Printed Simulator for Mitral Valve Transcatheter Edge-to-Edge Repair (TEER). MATERIALS 2022; 15:ma15124284. [PMID: 35744343 PMCID: PMC9227763 DOI: 10.3390/ma15124284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/13/2022] [Accepted: 06/15/2022] [Indexed: 11/17/2022]
Abstract
Mitral regurgitation is a common valvular disorder. Transcatheter edge-to-edge repair (TEER) is a minimally invasive technique which involves holding together the middle segments of the mitral valve leaflets, thereby reducing regurgitation. To date, MitraClip™ is the only Food and Drug Administration (FDA)-approved device for TEER. The MitraClip procedure is technically challenging, characterised by a steep learning curve. Training is generally performed on simplified models, which do not emphasise anatomical features, realistic materials, or procedural scenarios. The aim of this study is to propose a novel, 3D printed simulator, with a major focus on reproducing the anatomy and plasticity of all areas of the heart involved and specifically the ones of the mitral valve apparatus. A three-dimensional digital model of a heart was generated by segmenting computed tomography (CT). The model was subsequently modified for: (i) adding anatomical features not fully visible with CT; (ii) adapting the model to interact with the MitraClip procedural equipment; and (iii) ensuring modularity of the system. The model was manufactured with a Polyjet technology printer, with a differentiated material assignment among its portions. Polypropylene threads were stitched to replicate chordae tendineae. The proposed system was successfully tested with MitraClip equipment. The simulator was assessed to be feasible to practice in a realistic fashion, different procedural aspects including access, navigation, catheter steering, and leaflets grasping. In addition, the model was found to be compatible with clinical procedural imaging fluoroscopy equipment. Future studies will assess the effect of the proposed training system on improving TEER training.
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15
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Wolfes J, Ellermann C, Köbe J, Lange PS, Leitz P, Rath B, Willy K, Güner F, Frommeyer G, Eckardt L. [Anatomy of the left ventricle for endocardial ablation]. Herzschrittmacherther Elektrophysiol 2022; 33:161-174. [PMID: 35556156 DOI: 10.1007/s00399-022-00859-7] [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: 02/25/2022] [Accepted: 04/15/2022] [Indexed: 06/15/2023]
Abstract
As with all cardiac interventions, performing left ventricular ablation requires profound knowledge of cardiac anatomy. The aim of this article is to provide an overview of left ventricular anatomy and to characterize complex and clinically relevant structures from an electrophysiologist-centered perspective. In addition to the different access routes, the trabecular network, the left ventricular outflow tract, and the left ventricular conduction system, complex anatomical structures such as the aortomitral continuity and the left ventricular summit are also explained. In addition, this article offers multiple clinical examples that combine ECG, anatomy, and electrophysiologic study.
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Affiliation(s)
- Julian Wolfes
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland.
| | - Christian Ellermann
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Julia Köbe
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Philipp S Lange
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Patrick Leitz
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Benjamin Rath
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Kevin Willy
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Fatih Güner
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Gerrit Frommeyer
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
| | - Lars Eckardt
- Klinik für Kardiologie II-Rhythmologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland
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16
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Guigui SA, Torres C, Escolar E, Mihos CG. Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: a narrative review. J Thorac Dis 2022; 14:2309-2325. [PMID: 35813751 PMCID: PMC9264047 DOI: 10.21037/jtd-22-182] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 04/15/2022] [Indexed: 11/06/2022]
Abstract
Background and Objective The prevalence of hypertrophic cardiomyopathy (HCM) is estimated to be 1 in 200 to 500 individuals, with systolic anterior motion (SAM) of the mitral valve (MV) and left ventricular outflow tract (LVOT) obstruction present in 60% to 70%. In this narrative review, we aim to elucidate the pathophysiology of SAM-septal contact and LVOT obstruction in HCM by presenting a detailed review on the anatomy of the MV apparatus in HCM, examining the various existing theories pertaining to the SAM phenomenon as supported by cardiac imaging, and providing a critical assessment of management strategies for SAM in HCM. Methods A literature review was performed using PubMed, EMBASE, Ovid, and the Cochrane Library, of all scientific articles published through December 2021. A focus was placed on descriptive studies, reports correlating echocardiographic findings with pathologic diagnosis, and outcomes studies. Key Content and Findings The pathophysiology of SAM involves the complex interplay between HCM morphology, MV apparatus anatomic abnormalities, and labile hemodynamic derangements. Echocardiography and cardiac magnetic resonance (CMR) vector flow mapping have identified drag forces, as opposed to the "Venturi effect", as the main hydraulic forces responsible for SAM. The degree of mitral regurgitation with SAM is variable, and its severity is correlated with degree of LVOT obstruction and outcomes. First line therapy for the amelioration of SAM and LVOT obstruction is medical therapy with beta-blockers, non-dihydropyridine calcium-channel blockers, and disopyramide, in conjunction with lifestyle modifications. In refractory cases septal reduction therapy is performed, which may be combined with a 'resect-plicate-release' procedure, anterior mitral leaflet extension, surgical edge-to-edge MV repair, anterior mitral leaflet retention plasty, or secondary chordal cutting. Conclusions Recent scientific advances in the field of HCM have allowed for a maturation of our understanding of the SAM phenomenon. Cardiac imaging plays a critical role in its diagnosis, treatment, and surveillance, and in our ability to apply the appropriate therapeutic regimens. The increasing prevalence of HCM places an emphasis on continued basic and clinical research to further improve outcomes for this challenging population.
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Affiliation(s)
- Sarah A Guigui
- Echocardiography Laboratory, Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA.,Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA
| | - Christian Torres
- Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA
| | - Esteban Escolar
- Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA.,Coronary Care Unit, Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA
| | - Christos G Mihos
- Echocardiography Laboratory, Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA.,Columbia University Division of Cardiology, Mount Sinai Heart Institute, Miami Beach, FL, USA
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17
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Maleszewski JJ, Lai CK, Nair V, Veinot JP. Anatomic considerations and examination of cardiovascular specimens (excluding devices). Cardiovasc Pathol 2022. [DOI: 10.1016/b978-0-12-822224-9.00013-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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18
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Manohar P, Naik L R, Mohan Rao PS. Auto-Pericardial Mitral Valve Implantation: A Pilot Study. Heart Lung Circ 2021; 31:575-581. [PMID: 34656441 DOI: 10.1016/j.hlc.2021.09.015] [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: 06/14/2021] [Revised: 09/03/2021] [Accepted: 09/18/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Developing nations continue to grapple with rheumatic heart disease, particularly in the young. There is a need for an alternative to prosthetic mitral valve replacement in irreparable mitral valves, which avoids the need for anticoagulation and risks of thromboembolism. METHODS Twelve (12) patients with irreparable severe mitral valve disease underwent auto-pericardial mitral valve implantation from August 2020 to February 2021. The mitral valve leaflets were excised. Autologous pericardium treated with 0.5% glutaraldehyde for 8 minutes was fashioned into anterior and posterior mitral leaflets as per the dimensions on an indigenously designed template based on the studies by Ranganathan and Lam. The pericardial leaflets were sutured onto an appropriately sized mitral annuloplasty ring. The ring with the leaflets was implanted onto the mitral annulus. The leaflets were supported with neo-chordae prepared with Gore-Tex (W L Gore and Associates, Inc. Newark, DE, USA) and polyester sutures to mimic a repaired mitral valve in its structure and dynamics. RESULTS The mean cross-clamp time was 138±21.7 minutes. None of the patients required re-exploration. On the third postoperative day, a mean mitral valve orifice area of 3±0.47 cm and mean mitral valve gradient of 2±1.04 were observed. None of the patients had any more than 1+ mitral regurgitation. None of them have required a re-intervention for mitral insufficiency to date. DISCUSSION Auto-pericardial mitral valve re-implantation is a safe and effective procedure for severe, irreparable, mitral valve pathologies. However, the mid-term and long-term results need to be compared with conventional mitral valve replacement with a prosthetic valve in a randomised controlled trial.
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Affiliation(s)
- Prabhu Manohar
- Department of Cardiothoracic and Vascular Surgery, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, Karnataka, India.
| | - Rakesh Naik L
- Department of Cardiothoracic and Vascular Surgery, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, Karnataka, India
| | - Prasanna Simha Mohan Rao
- Department of Cardiothoracic and Vascular Surgery, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bangalore, Karnataka, India
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19
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Pang K, Wang J, Zhang T, Wu J, Gao Y, Liang Y, Ma K, Mao F, Pan X, Hu S, Li S. Undifferentiated Chordae Tendineae of the Mitral Valve: Large Cohort Study of a Rare Mitral Malformation. Front Cardiovasc Med 2021; 8:695536. [PMID: 34386530 PMCID: PMC8353112 DOI: 10.3389/fcvm.2021.695536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/22/2021] [Indexed: 12/05/2022] Open
Abstract
Aims: This study aimed to investigate the pathology, classification, diagnosis, and surgical prognosis of UCMV. Methods and Results: Consecutive paediatric patients with ≥ moderate-severe mitral regurgitation (MR) and mitral stenosis (MS) were recruited between October 2016 and July 2020. UCMV was diagnosed and classified into three grades according to the involvement of chorda groups and MS presence or absence; other mitral lesions were included as controls. Of 207 eligible patients, 75 with UCMV (10.0 m [interquartile range (IQR): 6.0–21.5]) and 110 with other mitral lesions (16.0 m [IQR: 5.0–43.5]) were diagnosed using echocardiography and surgical exploration. The associated chorda groups of UCMV were confirmed to show high agreement between echocardiography and surgery (kappa = 0.857, p < 0.001). At baseline surgery assessment, the UCMV group exhibited worse New York Heart Association functional class, more severe MR and MS grades, and fewer associated complex anomalies (all, p < 0.05) than the control group. After a mean follow-up of 8.3 (IQR:2.7–14.4) months and adjustment for covariates, the UCMV group required longer cardiopulmonary bypass and aortic clamp times, but there were no differences in the incidence of adverse events (p = 0.584). Class III was associated with higher risk of adverse events than classes I and II (p = 0.002). Conclusions: The UCMV spectrum constitutes a primary pathogenesis of paediatric MV dysfunction, which can be optimally diagnosed using echocardiography. Classification based on mitral anatomy and dysfunction can predict the risk of postoperative adverse events.
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Affiliation(s)
- Kunjing Pang
- Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jingjin Wang
- Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Tingting Zhang
- Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jinlin Wu
- Department of Cardiac Surgery, Guangdong Academy of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yiming Gao
- Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu Liang
- Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kai Ma
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Fengqun Mao
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiangbin Pan
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shengshou Hu
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shoujun Li
- Department of Cardiac Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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20
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de Oliveira DC, Espino DM, Deorsola L, Mynard JP, Rajagopal V, Buchan K, Dawson D, Shepherd DET. A toolbox for generating scalable mitral valve morphometric models. Comput Biol Med 2021; 135:104628. [PMID: 34246162 DOI: 10.1016/j.compbiomed.2021.104628] [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: 03/11/2021] [Revised: 06/25/2021] [Accepted: 07/02/2021] [Indexed: 11/26/2022]
Abstract
The mitral valve is a complex anatomical structure, whose shape is key to several traits of its function and disease, being crucial for the success of surgical repair and implantation of medical devices. The aim of this study was to develop a parametric, scalable, and clinically useful model of the mitral valve, enabling the biomechanical evaluation of mitral repair techniques through finite element simulations. MATLAB was used to parameterize the valve: the annular boundary was sampled from a porcine mitral valve mesh model and landmark points and relevant boundaries were selected for the parameterization of leaflets using polynomial fitting. Several geometric parameters describing the annulus, leaflet shape and papillary muscle position were implemented and used to scale the model according to patient dimensions. The developed model, available as a toolbox, allows for the generation of a population of models using patient-specific dimensions obtained from medical imaging or averaged dimensions evaluated from empirical equations based on the Golden Proportion. The average model developed using this framework accurately represents mitral valve shapes, associated with relative errors reaching less than 10% for annular and leaflet length dimensions, and less than 24% in comparison with clinical data. Moreover, model generation takes less than 5 min of computing time, and the toolbox can account for individual morphological variations and be employed to evaluate mitral valve biomechanics; following further development and validation, it will aid clinicians when choosing the best patient-specific clinical intervention and improve the design process of new medical devices.
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Affiliation(s)
- Diana C de Oliveira
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Daniel M Espino
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Luca Deorsola
- Paedriatic Cardiac Surgery, Ospedale Infantile Regina Margherita Sant Anna, Turin, 10126, Italy
| | - Jonathan P Mynard
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia; Heart Research, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, 3052, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, VIC, 3010, Australia; Department of Cardiology, Royal Children's Hospital, Melbourne, VIC, 3052, Australia
| | - Vijay Rajagopal
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Keith Buchan
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen, AB24 2ZN, Scotland, UK
| | - Dana Dawson
- School of Medicine, University of Aberdeen, Aberdeen, AB25 2ZD, Scotland, UK; Cardiology Department, Aberdeen Royal Infirmary, Aberdeen, AB25 2ZN, Scotland, UK
| | - Duncan E T Shepherd
- Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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21
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Kim DH. Multimodality Imaging for the Assessment of Mitral Valve Disease. Cardiol Clin 2021; 39:243-253. [PMID: 33894938 DOI: 10.1016/j.ccl.2021.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mitral valve disease is the most common valvular heart disease. Imaging determines the etiology (anatomic assessment), valve function and severity of valvular heart disease (hemodynamic assessment), remodeling of the left ventricle and right ventricle, and preplanning and guidance of percutaneous intervention. Although roles of computed tomography and magnetic resonance are increasing, echocardiography serves as the first-line imaging modality for the diagnosis and serial follow-up in most cases. This review summarizes the roles of multimodality imaging currently available from research fields to daily clinical practice.
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Affiliation(s)
- Dae-Hee Kim
- Division of Cardiology, Asan Medical Center, College of Medicine, University of Ulsan, 388-1, Poongnap-dong, Songpa-ku, Seoul 138-736, Korea.
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22
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Arrhythmic Mitral Valve Prolapse: Introducing an Era of Multimodality Imaging-Based Diagnosis and Risk Stratification. Diagnostics (Basel) 2021; 11:diagnostics11030467. [PMID: 33800155 PMCID: PMC7999774 DOI: 10.3390/diagnostics11030467] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 01/13/2023] Open
Abstract
Mitral valve prolapse is a common cardiac condition, with an estimated prevalence between 1% and 3%. Most patients have a benign course, but ever since its initial description mitral valve prolapse has been associated to sudden cardiac death. Although the causal relationship between mitral valve prolapse and sudden cardiac death has never been clearly demonstrated, different factors have been implicated in arrhythmogenesis in patients with mitral valve prolapse. In this work, we offer a comprehensive overview of the etiology and the genetic background, epidemiology, pathophysiology, and we focus on the state-of-the-art imaging-based diagnosis of mitral valve prolapse. Going beyond the classical, well-described clinical factors, such as young age, female gender and auscultatory findings, we investigate multimodality imaging features, such as alterations of anatomy and function of the mitral valve and its leaflets, the structural and contractile anomalies of the myocardium, all of which have been associated to sudden cardiac death.
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23
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Yang B, Lee PY, Hua Y, Brazile B, Waxman S, Ji F, Zhu Z, Sigal IA. Instant polarized light microscopy for imaging collagen microarchitecture and dynamics. JOURNAL OF BIOPHOTONICS 2021; 14:e202000326. [PMID: 33103363 PMCID: PMC7887070 DOI: 10.1002/jbio.202000326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/17/2020] [Accepted: 10/23/2020] [Indexed: 05/29/2023]
Abstract
Collagen fibers are a primary load-bearing component of connective tissues and are therefore central to tissue biomechanics and pathophysiology. Understanding collagen architecture and behavior under dynamic loading requires a quantitative imaging technique with simultaneously high spatial and temporal resolutions. Suitable techniques are thus rare and often inaccessible. In this study, we present instant polarized light microscopy (IPOL), in which a single snapshot image encodes information on fiber orientation and retardance, thus fulfilling the requirement. We utilized both simulation and experimental data from collagenous tissues of chicken tendon, sheep eye, and porcine heart to evaluate the effectiveness of IPOL as a quantitative imaging technique. We demonstrate that IPOL allows quantitative characterization of micron-scale collagen fiber architecture at full camera frame rates (156 frames/second herein).
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Affiliation(s)
- Bin Yang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Engineering, Rangos School of Health Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Po-Yi Lee
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Yi Hua
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Bryn Brazile
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Susannah Waxman
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Fengting Ji
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ziyi Zhu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ian A Sigal
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States
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24
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Constable M, Northeast R, Lawless BM, Burton HE, Gramigna V, Goh KL, Buchan KG, Espino DM. Mechanical testing of glutaraldehyde cross-linked mitral valves. Part two: Elastic and viscoelastic properties of chordae tendineae. Proc Inst Mech Eng H 2020; 235:291-299. [PMID: 33243079 DOI: 10.1177/0954411920975938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this study was to assess whether the mechanical properties of mitral valve chordae tendineae are sensitive to being cross-linked under load. A total 64 chordae were extracted from eight porcine hearts. Two chordae (posterior basal) from each heart were subjected to uniaxial ramp testing and six chordae (two strut, two anterior basal and two posterior basal) were subjected to dynamic mechanical analysis over frequencies between 0.5 and 10 Hz. Chordae were either cross-linked in tension or cross-linked in the absence of loading. Chordae cross-linked under load transitioned from high to low extension at a lower strain than cross-linked unloaded chordae (0.07 cf. 0.22), with greater pre-transitional (30.8 MPa cf. 5.78 MPa) and post-transitional (139 MPa cf. 74.1 MPa) moduli. The mean storage modulus of anterior strut chordae ranged from 48 to 54 MPa for cross-linked unloaded chordae, as compared to 53-61 MPa cross-linked loaded chordae. The mean loss modulus of anterior strut chordae ranged from 2.3 to 2.9 MPa for cross-linked unloaded chordae, as compared to 3.8-4.8 MPa cross-linked loaded chordae. The elastic and viscoelastic properties of chordae following glutaraldehyde cross-linking are dependent on the inclusion/exclusion of loading during the cross-linking process; with loading increasing the magnitude of the material properties measured.
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Affiliation(s)
- Matthew Constable
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | - Rhiannon Northeast
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | - Bernard M Lawless
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK.,Filament PD, Level 4 - Skypark 3, Skypark, Glasgow, UK
| | - Hanna E Burton
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | - Vera Gramigna
- University of Magna Graecia, Catanzaro, Italy.,IBFM, National Research Council, Germaneto, Catanzaro, Italy
| | - Kheng Lim Goh
- Department of Mechanical Engineering, University of Newcastle, Singapore
| | - Keith G Buchan
- Department of Cardio-thoracic Surgery, Aberdeen Royal Infirmary, Forresterhill, Aberdeen, UK
| | - Daniel M Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
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25
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Ross CJ, Hsu MC, Baumwart R, Mir A, Burkhart HM, Holzapfel GA, Wu Y, Lee CH. Quantification of load-dependent changes in the collagen fiber architecture for the strut chordae tendineae-leaflet insertion of porcine atrioventricular heart valves. Biomech Model Mechanobiol 2020; 20:223-241. [PMID: 32809131 PMCID: PMC8008705 DOI: 10.1007/s10237-020-01379-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 08/08/2020] [Indexed: 10/23/2022]
Abstract
Atrioventricular heart valves (AHVs) regulate the unidirectional flow of blood through the heart by opening and closing of the leaflets, which are supported in their functions by the chordae tendineae (CT). The leaflets and CT are primarily composed of collagen fibers that act as the load-bearing component of the tissue microstructures. At the CT-leaflet insertion, the collagen fiber architecture is complex, and has been of increasing focus in the previous literature. However, these previous studies have not been able to quantify the load-dependent changes in the tissue's collagen fiber orientations and alignments. In the present study, we address this gap in knowledge by quantifying the changes in the collagen fiber architecture of the mitral and tricuspid valve's strut CT-leaflet insertions in response to the applied loads by using a unique approach, which combines polarized spatial frequency domain imaging with uniaxial mechanical testing. Additionally, we characterized these microstructural changes across the same specimen without the need for tissue fixatives. We observed increases in the collagen fiber alignments in the CT-leaflet insertion with increased loading, as described through the degree of optical anisotropy. Furthermore, we used a leaflet-CT-papillary muscle entity method during uniaxial testing to quantify the chordae tendineae mechanics, including the derivation of the Ogden-type constitutive modeling parameters. The results from this study provide a valuable insight into the load-dependent behaviors of the strut CT-leaflet insertion, offering a research avenue to better understand the relationship between tissue mechanics and the microstructure, which will contribute to a deeper understanding of AHV biomechanics.
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Affiliation(s)
- Colton J Ross
- Biomechanics and Biomaterial Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Ryan Baumwart
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, 99164, USA
| | - Arshid Mir
- Department of Pediatric Cardiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Harold M Burkhart
- Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria.,Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Yi Wu
- Biomechanics and Biomaterial Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA
| | - Chung-Hao Lee
- Biomechanics and Biomaterial Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA. .,School of Aerospace and Mechanical Engineering, Affiliated Faculty, Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK, 73019, USA.
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26
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Chen S, Sari CR, Gao H, Lei Y, Segers P, De Beule M, Wang G, Ma X. Mechanical and morphometric study of mitral valve chordae tendineae and related papillary muscle. J Mech Behav Biomed Mater 2020; 111:104011. [PMID: 32835989 DOI: 10.1016/j.jmbbm.2020.104011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 07/07/2020] [Accepted: 07/21/2020] [Indexed: 01/21/2023]
Abstract
The mitral valve (MV) apparatus is a complex mechanical structure including annulus, valve leaflets, papillary muscles (PMs) and connected chordae tendineae. Chordae anchor to the papillary muscles to help the valve open and close properly during one cardiac cycle. It is of paramount importance to understand the functional, mechanical, and microstructural properties of mitral valve chordae and connecting PMs. In particular, little is known about the biomechanical properties of the anterior and posterior papillary muscle and corresponding chords. In this work, we performed uniaxial and biaxial tensile tests on the anterolateral (APM) and posteromedial papillary muscle (PPM), and their respective corresponding chordae tendineae, chordaeAPM and chordaePPM, in porcine hearts. Histology was carried out to link the microstructure and macro-mechanical behavior of the chordae and PMs. Our results demonstrate that chordaePPM are less in number, but significantly longer and stiffer than chordaeAPM. These different biomechanical properties may be partially explained by the higher collagen core ratio and larger collagen fibril density of chordaePPM. No significant mechanical or microstructural differences were observed along the circumferential and longitudinal directions of APM and PPM samples. Data measured on chordae and PMs were further fitted with the Ogden and reduced Holzapfel - Ogden strain energy functions, respectively. This study presents the first comparative anatomical, mechanical, and structural dataset of porcine mitral valve chordae and related PMs. Results indicate that a PM based classification of chordae will need to be considered in the analysis of the MV function or planning a surgical treatment, which will also help developing more precise computational models of MV.
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Affiliation(s)
- Shengda Chen
- College of Bioengineering, Chongqing University, Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing, 400030, China; IBiTech - BioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium; Numerical Simulation Center, Microport, Shanghai, China
| | - Candra Ratna Sari
- College of Bioengineering, Chongqing University, Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing, 400030, China
| | - Hao Gao
- School of Mathematics & Statistics, University of Glasgow, Glasgow, UK
| | - Yang Lei
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China
| | - Patrick Segers
- IBiTech - BioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Matthieu De Beule
- IBiTech - BioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium; FEops NV, Ghent, Belgium
| | - Guixue Wang
- College of Bioengineering, Chongqing University, Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing, 400030, China
| | - Xingshuang Ma
- College of Bioengineering, Chongqing University, Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Chongqing, 400030, China.
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27
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Taylor S, Buchan KG, Espino DM. The role of strut chordae in mitral valve competence during annular dilation. Perfusion 2020; 36:253-260. [PMID: 32693675 PMCID: PMC8041452 DOI: 10.1177/0267659120941340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Strut chordae, on their own, are not typically thought to aid mitral valve competence. The aim of this study is to assess whether strut chordae aid mitral valve competence during acute annular dilation. Twelve porcine hearts were dissected and tested using an in vitro simulator, with the mitral annulus tested in either a 'normal' or a dilated configuration. The normal configuration included a diameter of 30 mm, a posterior leaflet 'radius' of 15 mm and a commissural corner 'radius' of 7.5 mm; the dilated annular template instead used dimensions of 50 mm, 25 mm and 12.5 mm, respectively. Each mitral valve underwent ten repeat tests with a target systolic pressure of 100 mmHg. No significant difference in the pressure was detected between the dilated and regular annuli for the mitral valves tested (95 ± 3 mmHg cf. 95 ± 2 mmHg). However, the volume of regurgitation for a dilated annulus was 28 ml greater than for a valve with a normal annulus. Following severing of strut chordae, there was a significant reduction in the systolic pressure withstood before regurgitation by mitral valves with dilated annuli (60 ± 29 mmHg cf. 95 ± 2 mmHg for normal annular dimensions; p < 0.05). In conclusion, strut chordae tendineae may play a role in aiding mitral valve competence during pathophysiology.
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Affiliation(s)
- Samuel Taylor
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | - Keith G Buchan
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Daniel M Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
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28
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Taylor S, Buchan KG, Espino DM. The role of strut chordae in mitral valve competence during annular dilation. Perfusion 2020. [PMID: 32693675 DOI: 10.1177/0267659120941340.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Strut chordae, on their own, are not typically thought to aid mitral valve competence. The aim of this study is to assess whether strut chordae aid mitral valve competence during acute annular dilation. Twelve porcine hearts were dissected and tested using an in vitro simulator, with the mitral annulus tested in either a 'normal' or a dilated configuration. The normal configuration included a diameter of 30 mm, a posterior leaflet 'radius' of 15 mm and a commissural corner 'radius' of 7.5 mm; the dilated annular template instead used dimensions of 50 mm, 25 mm and 12.5 mm, respectively. Each mitral valve underwent ten repeat tests with a target systolic pressure of 100 mmHg. No significant difference in the pressure was detected between the dilated and regular annuli for the mitral valves tested (95 ± 3 mmHg cf. 95 ± 2 mmHg). However, the volume of regurgitation for a dilated annulus was 28 ml greater than for a valve with a normal annulus. Following severing of strut chordae, there was a significant reduction in the systolic pressure withstood before regurgitation by mitral valves with dilated annuli (60 ± 29 mmHg cf. 95 ± 2 mmHg for normal annular dimensions; p < 0.05). In conclusion, strut chordae tendineae may play a role in aiding mitral valve competence during pathophysiology.
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Affiliation(s)
- Samuel Taylor
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | - Keith G Buchan
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Daniel M Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
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29
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Topilsky Y. Mitral Regurgitation: Anatomy, Physiology, and Pathophysiology-Lessons Learned From Surgery and Cardiac Imaging. Front Cardiovasc Med 2020; 7:84. [PMID: 32548127 PMCID: PMC7272584 DOI: 10.3389/fcvm.2020.00084] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 04/20/2020] [Indexed: 02/04/2023] Open
Abstract
The normal mitral valve is a dynamic structure that permits blood to flow from the left atrial (LA) to left ventricle (LV) during diastole and sealing of the LA from the LV during systole. The main components of the mitral apparatus are the mitral annulus (MA), the mitral leaflets, the chordae tendineae, and the papillary muscles (PM) (Figure 1). Normal valve function is dependent on the integrity and normal interplay of these components. Abnormal function of any one of the components, or their interplay can result in mitral regurgitation (MR). Understanding the anatomy and physiology of all the component of the mitral valve is important for the diagnosis, and for optimal planning of repair procedures. In this review we will focus first on normal anatomy and physiology of the different parts of the mitral valve (MA, leaflets, chordae tendineae, and PM). In the second part we will focus on the pathologic anatomic and physiologic derangements associated with different types of MR.
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Affiliation(s)
- Yan Topilsky
- The Department of Cardiology, Tel Aviv Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
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30
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Oliveira D, Srinivasan J, Espino D, Buchan K, Dawson D, Shepherd D. Geometric description for the anatomy of the mitral valve: A review. J Anat 2020; 237:209-224. [PMID: 32242929 DOI: 10.1111/joa.13196] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/16/2022] Open
Abstract
The mitral valve is a complex anatomical structure whose physiological functioning relies on the biomechanical properties and structural integrity of its components. Their compromise can lead to mitral valve dysfunction, associated with morbidity and mortality. Therefore, a review on the morphometry of the mitral valve is crucial, more specifically on the importance of valve dimensions and shape for its function. This review initially provides a brief background on the anatomy and physiology of the mitral valve, followed by an analysis of the morphological information available. A characterisation of mathematical descriptions of several parts of the valve is performed and the impact of different dimensions and shape changes in disease is then outlined. Finally, a section regarding future directions and recommendations for the use of morphometric information in clinical analysis of the mitral valve is presented.
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Affiliation(s)
- Diana Oliveira
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | | | - Daniel Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
| | - Keith Buchan
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Dana Dawson
- Cardiology Research Facility, University of Aberdeen and Aberdeen Royal Infirmary, Aberdeen, UK
| | - Duncan Shepherd
- Department of Mechanical Engineering, University of Birmingham, Birmingham, UK
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31
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Ross CJ, Zheng J, Ma L, Wu Y, Lee CH. Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review. Bioengineering (Basel) 2020; 7:E25. [PMID: 32178262 PMCID: PMC7148526 DOI: 10.3390/bioengineering7010025] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 11/16/2022] Open
Abstract
The atrioventricular heart valves (AHVs) are responsible for directing unidirectional blood flow through the heart by properly opening and closing the valve leaflets, which are supported in their function by the chordae tendineae and the papillary muscles. Specifically, the chordae tendineae are critical to distributing forces during systolic closure from the leaflets to the papillary muscles, preventing leaflet prolapse and consequent regurgitation. Current therapies for chordae failure have issues of disease recurrence or suboptimal treatment outcomes. To improve those therapies, researchers have sought to better understand the mechanics and microstructure of the chordae tendineae of the AHVs. The intricate structures of the chordae tendineae have become of increasing interest in recent literature, and there are several key findings that have not been comprehensively summarized in one review. Therefore, in this review paper, we will provide a summary of the current state of biomechanical and microstructural characterizations of the chordae tendineae, and also discuss perspectives for future studies that will aid in a better understanding of the tissue mechanics-microstructure linking of the AHVs' chordae tendineae, and thereby improve the therapeutics for heart valve diseases caused by chordae failures.
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Affiliation(s)
- Colton J. Ross
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA; (C.J.R.); (Y.W.)
| | - Junnan Zheng
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhejiang University, Hangzhou 310058, China; (J.Z.); (L.M.)
| | - Liang Ma
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Zhejiang University, Hangzhou 310058, China; (J.Z.); (L.M.)
| | - Yi Wu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA; (C.J.R.); (Y.W.)
| | - Chung-Hao Lee
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA; (C.J.R.); (Y.W.)
- Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, OK 73019, USA
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32
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Maggiore P, Anastasius M, Huang AL, Blanke P, Leipsic J. Transcatheter Mitral Valve Repair and Replacement: Current Evidence for Intervention and the Role of CT in Preprocedural Planning-A Review for Radiologists and Cardiologists Alike. Radiol Cardiothorac Imaging 2020; 2:e190106. [PMID: 33778537 DOI: 10.1148/ryct.2020190106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/05/2019] [Accepted: 09/26/2019] [Indexed: 01/21/2023]
Abstract
The mitral valve is a complex structure with a three-dimensional saddle shape annulus. Mitral regurgitation occurs from leaflet coaptation failure that is either primary (a problem with the leaflets) or secondary (chamber dilatation in the setting of cardiomyopathy). There has been an increase in focus on transcatheter mitral valve interventions, for both mitral repair and replacement. These technologies have rapidly developed to provide treatment for a substantial number of patients with severe symptomatic mitral regurgitation who are at too high of a risk to undergo open heart surgery. CT assessment of the mitral valve has developed with equal rapidity, with regard to preprocedural planning for transcatheter therapies. This review will provide an overview of mitral valve anatomy, an update on the current transcatheter repair and replacement therapies, as well as a focused overview of the role of multislice CT in mitral assessment prior to intervention. © RSNA, 2020.
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Affiliation(s)
- Paul Maggiore
- Centre for Heart Valve Innovation, St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6
| | - Malcolm Anastasius
- Centre for Heart Valve Innovation, St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6
| | - Alex L Huang
- Centre for Heart Valve Innovation, St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6
| | - Philipp Blanke
- Centre for Heart Valve Innovation, St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6
| | - Jonathon Leipsic
- Centre for Heart Valve Innovation, St Paul's Hospital, University of British Columbia, 1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6
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33
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Ross CJ, Laurence DW, Hsu MC, Baumwart R, Zhao YD, Mir A, Burkhart HM, Holzapfel GA, Wu Y, Lee CH. Mechanics of Porcine Heart Valves' Strut Chordae Tendineae Investigated as a Leaflet-Chordae-Papillary Muscle Entity. Ann Biomed Eng 2020; 48:1463-1474. [PMID: 32006267 PMCID: PMC8048774 DOI: 10.1007/s10439-020-02464-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 01/23/2020] [Indexed: 11/28/2022]
Abstract
Proper blood flow through the atrioventricular heart valves (AHVs) relies on the holistic function of the valve and subvalvular structures, and a failure of any component can lead to life-threatening heart disease. A comprehension of the mechanical characteristics of healthy valvular components is necessary for the refinement of heart valve computational models. In previous studies, the chordae tendineae have been mechanically characterized as individual structures, usually in a clamping-based approach, which may not accurately reflect the in vivo chordal interactions with the leaflet insertion and papillary muscles. In this study, we performed uniaxial mechanical testing of strut chordae tendineae of the AHVs under a unique tine-based leaflet-chordae-papillary muscle testing to observe the chordae mechanics while preserving the subvalvular component interactions. Results of this study provided insight to the disparity of chordae tissue stress-stretch responses between the mitral valve (MV) and the tricuspid valve (TV) under their respective emulated physiological loading. Specifically, strut chordae tendineae of the MV anterior leaflet had peak stretches of 1.09-1.16, while peak stretches of 1.08-1.11 were found for the TV anterior leaflet strut chordae. Constitutive parameters were also derived for the chordae tissue specimens using an Ogden model, which is useful for AHV computational model refinement. Results of this study are beneficial to the eventual improvement of treatment methods for valvular disease.
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Affiliation(s)
- Colton J Ross
- Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK, 73019-3609, USA
| | - Devin W Laurence
- Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK, 73019-3609, USA
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Ryan Baumwart
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Yan D Zhao
- Department of Biostatistics and Epidemiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Arshid Mir
- Department of Pediatric Cardiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Harold M Burkhart
- Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria.,Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Yi Wu
- Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK, 73019-3609, USA
| | - Chung-Hao Lee
- Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK, 73019-3609, USA. .,Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, OK, 73019, USA.
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34
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Aulakh K, Aneja P, Garg S. A study of morphology of the chordae tendineae of the left ventricle in human cadaveric hearts of North West Indian population. NATIONAL JOURNAL OF CLINICAL ANATOMY 2020. [DOI: 10.4103/njca.njca_13_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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35
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Kang V, Johnston R, van de Kamp T, Faragó T, Federle W. Morphology of powerful suction organs from blepharicerid larvae living in raging torrents. BMC ZOOL 2019. [DOI: 10.1186/s40850-019-0049-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Suction organs provide powerful yet dynamic attachments for many aquatic animals, including octopus, squid, remora, and clingfish. While the functional morphology of suction organs from some cephalopods and fishes has been investigated in detail, there are only few studies on such attachment devices in insects. Here we characterise the morphology and ultrastructure of the suction attachment organs of net-winged midge larvae (genus Liponeura; Diptera: Blephariceridae) – aquatic insects that live on rocks in rapid alpine waterways where flow speeds can reach 3 m s− 1 – using scanning electron microscopy, confocal laser scanning microscopy, and X-ray computed micro-tomography (micro-CT). Furthermore, we study the function of these organs in vivo using interference reflection microscopy.
Results
We identified structural adaptations important for the function of the suction attachment organs in L. cinerascens and L. cordata. First, a dense array of spine-like microtrichia covering each suction disc comes into contact with the substrate upon attachment, analogous to hairy structures on suction organs from octopus, clingfish, and remora fish. These spine-like microtrichia may contribute to the seal and provide increased shear force resistance in high-drag environments. Second, specialised rim microtrichia at the suction disc periphery were found to form a continuous ring in close contact and may serve as a seal on a variety of surfaces. Third, a V-shaped cut on the suction disc (“V-notch“) is actively opened via two cuticular apodemes inserting on its flanks. The apodemes are attached to dedicated V-notch opening muscles, thereby providing a unique detachment mechanism. The complex cuticular design of the suction organs, along with specialised muscles that attach to them, allows blepharicerid larvae to generate powerful attachments which can withstand strong hydrodynamic forces and quickly detach for locomotion.
Conclusion
The suction organs from Liponeura are underwater attachment devices specialised for resisting extremely fast flows. Structural adaptations from these suction organs could translate into future bioinspired attachment systems that perform well on a wide range of surfaces.
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36
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Lee CH, Laurence DW, Ross CJ, Kramer KE, Babu AR, Johnson EL, Hsu MC, Aggarwal A, Mir A, Burkhart HM, Towner RA, Baumwart R, Wu Y. Mechanics of the Tricuspid Valve-From Clinical Diagnosis/Treatment, In-Vivo and In-Vitro Investigations, to Patient-Specific Biomechanical Modeling. Bioengineering (Basel) 2019; 6:E47. [PMID: 31121881 PMCID: PMC6630695 DOI: 10.3390/bioengineering6020047] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 12/29/2022] Open
Abstract
Proper tricuspid valve (TV) function is essential to unidirectional blood flow through the right side of the heart. Alterations to the tricuspid valvular components, such as the TV annulus, may lead to functional tricuspid regurgitation (FTR), where the valve is unable to prevent undesired backflow of blood from the right ventricle into the right atrium during systole. Various treatment options are currently available for FTR; however, research for the tricuspid heart valve, functional tricuspid regurgitation, and the relevant treatment methodologies are limited due to the pervasive expectation among cardiac surgeons and cardiologists that FTR will naturally regress after repair of left-sided heart valve lesions. Recent studies have focused on (i) understanding the function of the TV and the initiation or progression of FTR using both in-vivo and in-vitro methods, (ii) quantifying the biomechanical properties of the tricuspid valve apparatus as well as its surrounding heart tissue, and (iii) performing computational modeling of the TV to provide new insight into its biomechanical and physiological function. This review paper focuses on these advances and summarizes recent research relevant to the TV within the scope of FTR. Moreover, this review also provides future perspectives and extensions critical to enhancing the current understanding of the functioning and remodeling tricuspid valve in both the healthy and pathophysiological states.
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Affiliation(s)
- Chung-Hao Lee
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
- Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, OK 73019, USA.
| | - Devin W Laurence
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Colton J Ross
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Katherine E Kramer
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
| | - Anju R Babu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
- Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, Odisha 769008, India.
| | - Emily L Johnson
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
| | - Ming-Chen Hsu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
| | - Ankush Aggarwal
- Glasgow Computational Engineering Centre, School of Engineering, University of Glasgow, Scotland G12 8LT, UK.
| | - Arshid Mir
- Division of Pediatric Cardiology, Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Harold M Burkhart
- Division of Cardiothoracic Surgery, Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Rheal A Towner
- Advance Magnetic Resonance Center, MS 60, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
| | - Ryan Baumwart
- Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Yi Wu
- Biomechanics and Biomaterials Design Laboratory, School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK 73019, USA.
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Culmone C, Ali A, Scali M, Menciassi A, Breedveld P. ChoRe: A device for trans-catheter chordae tendineae repair. Proc Inst Mech Eng H 2019; 233:712-722. [PMID: 31064250 PMCID: PMC6573001 DOI: 10.1177/0954411919848856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This work focuses on the design of a new device (called ChoRe) to place artificial chords in the mitral valve structure during a trans-catheter procedure. The aim of the device is to restore the correct functionality of the valve and solve mitral valve regurgitation, that is, a common consequence of chordae tendineae rupture. An analysis of the requirements was carried out and used to design and develop a first functional prototype. The resulting device was able to connect artificial chords at the posterior leaflet of the mitral valve and at the apex of the left ventricle, also allowing the control of the artificial chord length. The ChoRe was tested ex-vivo in bovine hearts. The qualitative assessment of the ChoRe focused on the performance of the device and preliminary evaluation of the procedure time. Results demonstrated that the device is able to create a top and bottom fixation in an average time of 3.45 ± 1.44 min. Future improvements will focus on enhancing the connection at the leaflet, as well as the overall functionality, in order to guarantee better control of the artificial chord length. This work shows future potentials for more patient-specific treatments in trans-catheter scenarios for mitral valve repair.
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Affiliation(s)
- Costanza Culmone
- 1 Bio-Inspired Technology Group (BITE), Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Awaz Ali
- 1 Bio-Inspired Technology Group (BITE), Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Marta Scali
- 1 Bio-Inspired Technology Group (BITE), Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Arianna Menciassi
- 2 The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Paul Breedveld
- 1 Bio-Inspired Technology Group (BITE), Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
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Morud JC, Skjetne P, Urheim S, Dahl SK. The effect of chordae tendineae on systolic flow. Comput Biol Med 2019; 109:91-100. [PMID: 31054389 DOI: 10.1016/j.compbiomed.2019.04.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/10/2019] [Accepted: 04/20/2019] [Indexed: 11/25/2022]
Abstract
When using Computational Fluid Dynamics to simulate ventricular blood flow in the heart, it has been common practice to neglect the effect of the sub-valvular apparatus and the trabeculae on the flow conditions. In this study, we analyze the effect of neglecting the chordae tendineae on the fluid flow and pressure drop. To test the assumption we use a previously developed dynamic 3D model of the left ventricle, aorta and valves that is based on 3D echocardiographic recordings. To this model we add the chordae tendineae as a sub-grid model. The previously developed 3D model for the left ventricle during systole is based on real-time three-dimensional echocardiography (RT3DE) recordings of a 30 years old female volunteer. The segmented ventricular wall does not include details of the aorta and the mitral valve, so these were reconstructed. The subgrid model for the flow across the chordae tendineae is based on the Actuator Line Method, which means that they are represented by drag coefficients. The analysis shows that the effect of the chordae tendineae on the pressure drop and work efficiency of the normal heart during systole is minor, and it seems that for simulating ventricular fluid flow and pressure drop during systole, one can follow the current practice and ignore the chordae. However, there can be local effects such as small vortices behind the chordae. Whether such effects are important for a particular application must be evaluated for the given case.
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Sardari Nia P, Daemen JH, Maessen JG. Development of a high-fidelity minimally invasive mitral valve surgery simulator. J Thorac Cardiovasc Surg 2019; 157:1567-1574. [DOI: 10.1016/j.jtcvs.2018.09.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/19/2018] [Accepted: 09/04/2018] [Indexed: 11/25/2022]
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Comparative mechanical, morphological, and microstructural characterization of porcine mitral and tricuspid leaflets and chordae tendineae. Acta Biomater 2019; 85:241-252. [PMID: 30579963 DOI: 10.1016/j.actbio.2018.12.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 11/30/2018] [Accepted: 12/19/2018] [Indexed: 11/23/2022]
Abstract
BACKGROUND Healthy function of tricuspid valve (TV) structures is essential to avoid tricuspid regurgitation (TR) and may significantly improve disease prognosis. Mitral valve (MV) structures have been extensively studied, but little is known about the TV and right-sided heart diseases. Therefore, clinical decisions and finite element (FE) simulations often rely heavily on MV data for TV applications, despite fundamentally different mechanical and physiological environments. METHOD/RESULTS To bridge this gap, we performed a rigorous mechanical, morphological, and microstructural characterization of the MV and TV leaflets and chordae in a porcine model. Planar biaxial testing, uniaxial testing, second harmonic generation imaging and Verhoeff Van Gieson staining were performed. Morphological parameters, tissue moduli, extensibility, and anisotropy were quantified and compared. No major differences in leaflet mechanics or structure were found between TV and MV; chordal mechanics, morphology, and structure were found to compensate for anatomical and physiological loading differences between the valves. No differences in chordal mechanics were observed by insertion point within a leaflet; the septal tricuspid leaflet (STL) and posterior mitral leaflet (PML) did not have distinguishable strut chords, and the STL had the shortest chords. Within a valve, chords from septally-located leaflets were more extensible. MV chords were stiffer. CONCLUSIONS This study presents the first rigorous comparative mechanical and structural dataset of MV and TV structures. Valve type and anatomical location may be stronger predictors of chordal mechanics. Chords from septally-located leaflets differ from each other and from their intravalvular counterparts; they merit special consideration in surgical and computational applications. STATEMENT OF SIGNIFICANCE A better understanding of the tricuspid valve (TV) and its associated structures is important for making advancements towards the repair of tricuspid regurgitation. Mitral valve structures have been extensively studied, but little is known about the TV and right-sided heart diseases. Clinical decisions and computational simulations often rely heavily on MV data for TV applications, despite fundamentally different environments. We therefore performed a rigorous mechanical, morphological, and microstructural characterization of atrioventricular leaflets and chordae tendineae in a porcine model. Finding that valve type and anatomical location may be strong predictors of chordal mechanics, chords from septally-located leaflets differ from each other and from their intravalvular counterparts; they merit special consideration in surgical and computational applications.
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Jett S, Laurence D, Kunkel R, Babu AR, Kramer K, Baumwart R, Towner R, Wu Y, Lee CH. An investigation of the anisotropic mechanical properties and anatomical structure of porcine atrioventricular heart valves. J Mech Behav Biomed Mater 2018; 87:155-171. [PMID: 30071486 PMCID: PMC8008704 DOI: 10.1016/j.jmbbm.2018.07.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 05/05/2018] [Accepted: 07/15/2018] [Indexed: 11/18/2022]
Abstract
Valvular heart diseases are complex disorders, varying in pathophysiological mechanism and affected valve components. Understanding the effects of these diseases on valve functionality requires a thorough characterization of the mechanics and structure of the healthy heart valves. In this study, we performed biaxial mechanical experiments with extensive testing protocols to examine the mechanical behaviors of the mitral valve and tricuspid valve leaflets. We also investigated the effect of loading rate, testing temperatures, species (porcine versus ovine hearts), and age (juvenile vs adult ovine hearts) on the mechanical responses of the leaflet tissues. In addition, we evaluated the structure of chordae tendineae within each valve and performed histological analysis on each atrioventricular leaflet. We found all tissues displayed a characteristic nonlinear anisotropic mechanical response, with radial stretches on average 30.7% higher than circumferential stretches under equibiaxial physiological loading. Tissue mechanical responses showed consistent mechanical stiffening in response to increased loading rate and minor temperature dependence in all five atrioventricular heart valve leaflets. Moreover, our anatomical study revealed similar chordae quantities in the porcine mitral (30.5 ± 1.43 chords) and tricuspid valves (35.3 ± 2.45 chords) but significantly more chordae in the porcine than the ovine valves (p < 0.010). Our histological analyses quantified the relative thicknesses of the four distinct morphological layers in each leaflet. This study provides a comprehensive database of the mechanics and structure of the atrioventricular valves, which will be beneficial to development of subject-specific atrioventricular valve constitutive models and toward multi-scale biomechanical investigations of heart valve function to improve valvular disease treatments.
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Affiliation(s)
- Samuel Jett
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA
| | - Devin Laurence
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA
| | - Robert Kunkel
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA
| | - Anju R Babu
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA
| | - Katherine Kramer
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA
| | - Ryan Baumwart
- Center for Veterinary Health Sciences, Oklahoma State University, 208 S. McFarland Street, Stillwater, OK 74078, USA
| | - Rheal Towner
- Advanced Magnetic Resonance Center, MS 60, Oklahoma Medical Research Foundation 825 N.E. 13th Street, Oklahoma City, OK 73104, USA
| | - Yi Wu
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA
| | - Chung-Hao Lee
- School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219 C, Norman, OK 73019, USA; Institute for Biomedical Engineering, Science and Technology (IBEST), The University of Oklahoma, Norman, OK 73019, USA.
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Constable M, Burton HE, Lawless BM, Gramigna V, Buchan KG, Espino DM. Effect of glutaraldehyde based cross-linking on the viscoelasticity of mitral valve basal chordae tendineae. Biomed Eng Online 2018; 17:93. [PMID: 30001710 PMCID: PMC6044032 DOI: 10.1186/s12938-018-0524-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/05/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mitral valve failure can require repair or replacement. Replacement bioprosthetic valves are treated with glutaraldehyde prior to implantation. The aim of this study was to determine the changes in mechanical properties following glutaraldehyde fixation of mitral valve chordae. METHODS To investigate the impact of glutaraldehyde on mitral valve chordae, 24 basal chordae were dissected from four porcine hearts. Anterior and posterior basal (including strut) chordae were used. All 24 chordae were subjected to a sinusoidally varying load (mean level 2N, dynamic amplitude 2N) over a frequency range of 0.5-10 Hz before and after glutaraldehyde treatment. RESULTS The storage and loss modulus of all chordal types decreased following glutaraldehyde fixation. The storage modulus ranged from: 108 to 119 MPa before fixation and 67.3-87.4 MPa following fixation for basal chordae; 52.3-58.4 MPa before fixation and 47.9-53.5 MPa following fixation for strut chordae. Similarly, the loss modulus ranged from: 5.47 to 6.25 MPa before fixation and 3.63-4.94 MPa following fixation for basal chordae; 2.60-2.97 MPa before fixation and 2.31-2.93 MPa following fixation for strut chordae. CONCLUSION The viscoelastic properties of mitral valve chordae are affected by glutaraldehyde fixation; in particular, the reduction in storage moduli decreased with an increase in chordal diameter.
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Affiliation(s)
- M Constable
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - H E Burton
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.,PDR, International Centre for Design and Research, Cardiff Metropolitan University, Cardiff, CF5 2YB, UK
| | - B M Lawless
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK
| | - V Gramigna
- University of Magna Graecia, Catanzaro, Italy.,IBFM, National Research Council, Germaneto, Catanzaro, Italy
| | - K G Buchan
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, AB25 2ZN, UK
| | - D M Espino
- Department of Mechanical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
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Pozzoli A, Zuber M, Reisman M, Maisano F, Taramasso M. Comparative Anatomy of Mitral and Tricuspid Valve: What Can the Interventionlist Learn From the Surgeon. Front Cardiovasc Med 2018; 5:80. [PMID: 30009160 PMCID: PMC6033960 DOI: 10.3389/fcvm.2018.00080] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/11/2018] [Indexed: 11/13/2022] Open
Abstract
Transcatheter valve interventions on the mitral and tricuspid valves entail increasing complexity. Part of the knowledge that has been generated during the development of mitral devices can be transferred to the tricuspid valve (TV). However, a deeper understanding of the peculiar anatomy of the TV and of the right heart chambers, together with differences and similarities between the two valves, is fundamental. This report compares the anatomy of the mitral and tricuspid valves, and its inferences with regard to transcatheter treatments. Condensed abstract This report explores anatomical similarities and differences between the mitral and the tricuspid valves, and their implications with regard to transcatheter treatments.
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Affiliation(s)
- Alberto Pozzoli
- Heart Valve Clinic, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Michel Zuber
- Heart Valve Clinic, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Mark Reisman
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA, United States
| | - Francesco Maisano
- Heart Valve Clinic, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
| | - Maurizio Taramasso
- Heart Valve Clinic, University Hospital of Zurich, University of Zurich, Zurich, Switzerland
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Gaidulis G, Votta E, Selmi M, Aidietienė S, Aidietis A, Kačianauskas R. Numerical simulation of transapical off-pump mitral valve repair with neochordae implantation. Technol Health Care 2018; 26:635-645. [PMID: 29843286 DOI: 10.3233/thc-182510] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Transapical off-pump mitral valve (MV) repair is a novel minimally-invasive surgical technique, allowing to correct mitral regurgitation (MR) caused by chordae tendineae rupture. While numerical simulation of the MV structure has proven to be useful to evaluate the effects of the MV surgical repair techniques, no numerical simulation studies on the outcomes of transapical MV repair have been done up to now. OBJECTIVE The purpose of this study is to evaluate the transapical MV repair using finite element modeling and to determine the effect of the neochordal length on the function of the prolapsing MV. METHODS The reconstruction of the MV geometry based on the patient-specific data was performed. In order to simulate prolapse, chordae inserted into the middle segment of the posterior leaflet (P2) were ruptured. A total of four virtual transapical repairs using neochordae of different length were performed. The function of the MV before and after virtual repairs was simulated. RESULTS The evaluation of the effect of the neochordal length on post-repair MV function showed that the length of the implanted neochordae has a significant impact on the correction of MR caused by chordae tendineae rupture. CONCLUSIONS The presented results can improve the understanding of the effects of transapical MV repair.
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Affiliation(s)
- Gediminas Gaidulis
- Department of Biomechanical Engineering, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Emiliano Votta
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Matteo Selmi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.,Division of Cardiac Surgery, Department of Surgery, Università di Verona, Verona, Italy
| | - Sigita Aidietienė
- Department of Cardiovascular Medicine, Vilnius University, Vilnius, Lithuania
| | - Audrius Aidietis
- Department of Cardiovascular Medicine, Vilnius University, Vilnius, Lithuania
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45
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Anatomy of the mitral subvalvular apparatus. J Thorac Cardiovasc Surg 2018; 155:2002-2010. [DOI: 10.1016/j.jtcvs.2017.12.061] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/05/2017] [Accepted: 12/16/2017] [Indexed: 11/21/2022]
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46
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Varadarajan P, Pai RG. Strings of the Heart. J Am Soc Echocardiogr 2017; 30:1169-1171. [PMID: 29202950 DOI: 10.1016/j.echo.2017.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Padmini Varadarajan
- Division of Cardiology, Loma Linda University Medical Center, Loma Linda, California
| | - Ramdas G Pai
- Division of Cardiology, Department of Medicine, UCR School of Medicine, Riverside, California.
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Abstract
Mitral regurgitation (MR) is the most prevalent cause of valvular heart disease (VHD) in western countries. In the Euro Heart Survey on VHD, MR was the second most common heart VHD requiring surgery. It is also the most common form of VHD in community and population-based studies from the United States. The categorization of MR based on causes and mechanisms is a major determinant of clinical outcome, of possible therapies for the MR and of the effectiveness of these therapies. Surgical mitral valve (MV) repair has been shown to improve survival in patients with severe primary MR compared with MV replacement. In addition, new percutaneous repair and replacement procedures have been recently developed. Hence, accurate understanding of the functional anatomy of the MV and the pathophysiologic principles underlying MR is needed to appropriately target valve lesions. Recent advances in cardiac imaging have allowed to deeply strengthen the knowledge of the function of the MV. The present review aims at describing the functional anatomy and pathophysiology of MR through different cardiac imaging modalities.
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48
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Harari R, Bansal P, Yatskar L, Rubinstein D, Silbiger JJ. Papillary muscle rupture following acute myocardial infarction: Anatomic, echocardiographic, and surgical insights. Echocardiography 2017; 34:1702-1707. [PMID: 29082549 DOI: 10.1111/echo.13739] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Papillary muscle (PM) rupture is a rare complication of acute myocardial infarction which carries an excessive mortality rate. Optimal outcomes require rapid diagnosis and prompt surgical referral, and in this regard, echocardiography plays a crucial role. Comprehensive echocardiographic examination of the patient with PM rupture consists of identification of the ruptured PM segment, visualization of flail mitral valve segment(s), evaluation of mitral regurgitation severity, and assessment of left ventricular systolic function. This article discusses anatomic and echocardiographic features as well as the surgical management of PM rupture.
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Affiliation(s)
- Rafael Harari
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Priya Bansal
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Leonid Yatskar
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Pappalardo O, Sturla F, Onorati F, Puppini G, Selmi M, Luciani G, Faggian G, Redaelli A, Votta E. Mass-spring models for the simulation of mitral valve function: Looking for a trade-off between reliability and time-efficiency. Med Eng Phys 2017; 47:93-104. [DOI: 10.1016/j.medengphy.2017.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/23/2017] [Accepted: 07/03/2017] [Indexed: 11/27/2022]
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50
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Cardiac CT for Guiding Mitral Valve Interventions. CURRENT CARDIOVASCULAR IMAGING REPORTS 2017. [DOI: 10.1007/s12410-017-9428-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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