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Hussain N, Bhagia G, Doyle M, Rayarao G, Williams RB, Biederman RW. Mitral annular disjunction; how accurate are we? A cardiovascular MRI study defining risk. IJC HEART & VASCULATURE 2023; 49:101298. [PMID: 38035256 PMCID: PMC10682655 DOI: 10.1016/j.ijcha.2023.101298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/02/2023] [Accepted: 11/05/2023] [Indexed: 12/02/2023]
Abstract
Aims Mitral Annular Disjunction (MAD) refers to embryologic fibrous separation between mitral annular ring and basal left ventricular myocardium. Since its original description, the role of MAD in arrhythmic mitral valve prolapse (MVP) has been the subject of active research. In this study we sought to assess prognostic and imaging characteristics of MVP patients with and without underlying MAD. Methods and results Patients with posterior or bi-leaflet MVP were retrospectively identified via a review of all patients referred to our cardiac magnetic resonance (CMR) imaging laboratory from January 2015 to May 2022. MVP patients were further stratified by underlying MAD status. A total of 100 MVP patients undergoing CMR imaging (52 MVP patients with posterior MAD) were retrospectively identified with female comprising 55 % of the cohort. MVP patients with MAD were more likely to have an abnormal basal inferolateral/ papillary muscles LGE (51 % vs 21 %, p < 0.01). Posterior MAD longitudinal disjunction gap in 'mm' was a predictor of ventricular tachycardia (VT) [1.29, p = 0.01)]. Using ROC curve analysis, a disjunction gap of ≥ 4 mm was predictive of VT (AUC-0.71, p < 0.01), and incorporation of LGE in ROC model further improved AUC to 0.78 confirmed via Akaike information criterion (p < 0.01). Conclusion Abnormal LGE involving basal inferolateral myocardium and papillary muscles may provide etiologic substrate for arrythmia in MVP patients.
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Affiliation(s)
- Nasir Hussain
- Allegheny Health Network, Allegheny General Hospital, Center for Cardiovascular MRI, Pittsburgh, PA 15212, USA
- Wilson Medical Center, United Health Service, Johnson City, NY 13790, USA
| | - Geeta Bhagia
- Allegheny Health Network, Allegheny General Hospital, Center for Cardiovascular MRI, Pittsburgh, PA 15212, USA
- Benefis Health System, Great Falls, MT 59404, USA
| | - Mark Doyle
- Allegheny Health Network, Allegheny General Hospital, Center for Cardiovascular MRI, Pittsburgh, PA 15212, USA
| | - Geetha Rayarao
- Allegheny Health Network, Allegheny General Hospital, Center for Cardiovascular MRI, Pittsburgh, PA 15212, USA
| | - Ronald B. Williams
- Allegheny Health Network, Allegheny General Hospital, Center for Cardiovascular MRI, Pittsburgh, PA 15212, USA
| | - Robert W.W. Biederman
- Allegheny Health Network, Allegheny General Hospital, Center for Cardiovascular MRI, Pittsburgh, PA 15212, USA
- West Virginia University, Morgantown, WV 26506, USA
- Medical University of South Carolina, Charleston, SC 29425, USA
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Stephens SE, Kammien AJ, Paris JC, Applequist AP, Ingels NB, Jensen HK, Rodgers DE, Cole CR, Wenk JF, Jensen MO. In Vitro Mitral Valve Model with Unrestricted Ventricular Access: Using Vacuum to Close the Valve and Enable Static Trans-Mitral Pressure. J Cardiovasc Transl Res 2022; 15:845-854. [PMID: 34993757 PMCID: PMC9256857 DOI: 10.1007/s12265-021-10199-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/13/2021] [Indexed: 11/27/2022]
Abstract
Current in vitro models of the left heart establish the pressure difference required to close the mitral valve by sealing and pressurizing the ventricular side of the valve, limiting important access to the subvalvular apparatus. This paper describes and evaluates a system that establishes physiological pressure differences across the valve using vacuum on the atrial side. The subvalvular apparatus is open to atmospheric pressure and accessible by tools and sensors, establishing a novel technique for experimentation on atrioventricular valves. Porcine mitral valves were excised and closed by vacuum within the atrial chamber. Images were used to document and analyze closure of the leaflets. Papillary muscle force and regurgitant flow rate were measured to be 4.07 N at 120 mmHg and approximately 12.1 ml/s respectively, both of which are within clinically relevant ranges. The relative ease of these measurements demonstrates the usefulness of improved ventricular access at peak pressure/force closure.
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Affiliation(s)
- Sam E Stephens
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Alexander J Kammien
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Jacob C Paris
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Alexis P Applequist
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Neil B Ingels
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Hanna K Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA.,Department of Surgery, University of Arkansas for Medical Sciences, Fayetteville, AR, USA
| | - Drew E Rodgers
- Department of Anesthesiology, Washington Regional Medical Center, Fayetteville, AR, USA
| | - Charles R Cole
- Department of Cardiovascular Surgery, Washington Regional Medical Center, Fayetteville, AR, USA
| | - Jonathan F Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - Morten O Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA.
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3
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Zeng G, Li G, Jia Y, Chen S, Chen P, He Z. Detachment Force of the Helical Anchor in Mitral Annulus. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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4
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Hei S, Iwataki M, Jang JY, Kuwaki H, Fukuda S, Kim YJ, Toki M, Onoue T, Hayashi A, Nishino S, Watanabe N, Hayashida A, Tsuda Y, Araki M, Nishimura Y, Song JK, Yoshida K, Levine RA, Otsuji Y. Relations of Augmented Systolic Annular Expansion and Leaflet/Papillary Muscle Dynamics in Late-Systolic Mitral Valve Prolapse Evaluated by Echocardiography with a Speckle Tracking Analysis. Int Heart J 2020; 61:970-978. [PMID: 32999196 DOI: 10.1536/ihj.20-236] [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: 11/18/2022]
Abstract
The mechanism of systolic annular expansion in mitral valve prolapse (MVP) is not clarified. Since annular expansion is systolic outward shift of MV leaflet/chorda tissue complex at superior and outer ends, annular expansion could be related to inward (superior) shift of the complex at another inferior and inner end of the papillary muscle (PM) tip and/or systolic lengthening of the tissue complex, especially MV leaflets.MV annulus systolic expansion, PMs' systolic superior shift, and MV leaflets' systolic lengthening were evaluated by echocardiography with a speckle tracking analysis in 25 normal subjects, 25 subjects with holo-systolic MVP and 20 subjects with late-systolic MVP.PMs' superior shift, MV leaflets' lengthening, MV annular area at the onset of systole and subsequent MV annulus expansion were significantly greater in late-systolic MVP than in holo-systolic MVP (4.6 ± 1.6 versus 1.5 ± 0.7 mm/m2, 2.5 ± 1.4 versus 0.6 ± 2.0 mm/m2, 6.8 ± 2.5 versus 5.7 ± 1.0 cm2/m2 and 1.6 ± 0.8 versus 0.1 ± 0.5 cm2/m2, P < 0.001, respectively). Multivariate analysis identified MV leaflets' lengthening and PMs' superior shift as independent factors associated with MV annular expansion.Conclusions: These results suggest that systolic MV annular expansion in MVP is related to abnormal MV leaflets' lengthening and PMs' superior shift.
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Affiliation(s)
- Soshi Hei
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Mai Iwataki
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Jeong-Yoon Jang
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine
| | - Hiroshi Kuwaki
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Shota Fukuda
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Yun-Jeong Kim
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine
| | - Misako Toki
- Department of Clinical Laboratory, The Sakakibara Heart Institute of Okayama
| | - Takeshi Onoue
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Atsushi Hayashi
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Shun Nishino
- Department of Cardiology, Miyazaki Medical Association Hospital Cardiovascular Center
| | - Nozomi Watanabe
- Department of Cardiology, Miyazaki Medical Association Hospital Cardiovascular Center
| | | | - Yuki Tsuda
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Masaru Araki
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
| | - Yosuke Nishimura
- Department of Cardiovascular Surgery, University of Occupational and Environmental Health, School of Medicine
| | - Jae-Kwan Song
- Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine
| | - Kiyoshi Yoshida
- Department of Cardiology, The Sakakibara Heart Institute of Okayama
| | - Robert A Levine
- Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School
| | - Yutaka Otsuji
- Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine
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5
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Noack T, Kiefer P, Vivell N, Sieg F, Marin-Cuartas M, Leontyev S, Holzhey DM, Garbade J, Pfannmueller B, Davierwala P, Misfeld M, Seeburger J, Borger MA. Annuloplasty ring dehiscence after mitral valve repair: incidence, localization and reoperation. Eur J Cardiothorac Surg 2020; 57:300-307. [PMID: 31369069 DOI: 10.1093/ejcts/ezz219] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/24/2019] [Accepted: 07/02/2019] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Mitral valve (MV) annuloplasty ring dehiscence with subsequent recurrent mitral regurgitation represents an unusual but challenging clinical problem. Incidence, localization and outcomes for this complication have not been well defined. METHODS From 1996 to 2016, a total of 3478 patients underwent isolated MV repair with ring annuloplasty at the Leipzig Heart Centre. Of these patients, 57 (1.6%) underwent reoperation due to annuloplasty ring dehiscence. Echocardiographic data, operative and early postoperative characteristics as well as short- and long-term survival rates after MV reoperation were analysed. RESULTS Occurrences of ring dehiscence were acute (<30 days), early (≤1 year) and late (>1 year) in 44%, 33% and 23% of patients, respectively. Localization of annuloplasty ring dehiscence was found most frequently in the P3 segment (68%), followed by the P2 (51%) and the P1 segments (47%). The 30-day mortality rate and 1- and 5-year survival rates after MV reoperation were 2%, 89% and 74%, respectively. During reoperation, MV replacement was performed in 38 (67%) and MV re-repair in 19 (33%) patients. CONCLUSIONS Annuloplasty ring dehiscence is clinically less common, localized more frequently on the posterior annulus and occurs mostly acutely or early after MV repair. MV reoperation can be performed safely in such patients.
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Affiliation(s)
- Thilo Noack
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Philipp Kiefer
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Nina Vivell
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Franz Sieg
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Mateo Marin-Cuartas
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Sergey Leontyev
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | | | - Jens Garbade
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Bettina Pfannmueller
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Piroze Davierwala
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Martin Misfeld
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
| | - Joerg Seeburger
- University Department of Cardiac Surgery, Heart Centre Leipzig, Leipzig, Germany
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6
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Zhou Z, Gao B, Jing T, Wang S, Parameswaran S, He Z. How and where the mitral valve leaks in functional mitral regurgitation. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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7
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Markham R, Kyranis S, Aroney N, Lau K, Poon K, Scalia G, Walters D. Transcatheter mitral valve intervention: an emerging treatment for mitral regurgitation. Intern Med J 2018; 48:382-390. [PMID: 29623986 DOI: 10.1111/imj.13750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/26/2017] [Accepted: 09/28/2017] [Indexed: 11/29/2022]
Abstract
Mitral regurgitation (MR) is a valvular heart disease associated with significant morbidity and mortality. Transcatheter mitral valve intervention (TMVI) repairs or replaces the mitral valve through small arterial and venous entry sites and so avoids risks associated with open heart surgery. Transcatheter devices targeting components of the mitral apparatus are being developed to repair or replace it. Numerous challenges remain including developing more adaptable devices and correction of multiple components of the mitral annulus to attain durable results. The mitral valve apparatus is a complex structure and understanding of the mechanisms of MR is essential in the development of TMVI. There will likely be a complementary role between surgery and TMVI in the near future.
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Affiliation(s)
- Ryan Markham
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Stephen Kyranis
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas Aroney
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Katherine Lau
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Karl Poon
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Gregory Scalia
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Darren Walters
- Department of Cardiology, The Prince Charles Hospital, Brisbane, Queensland, Australia.,School of Medicine, University of Queensland, Brisbane, Queensland, Australia
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8
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Basu A, He Z. Annulus Tension on the Tricuspid Valve: An In-Vitro Study. Cardiovasc Eng Technol 2016; 7:270-9. [PMID: 27350138 DOI: 10.1007/s13239-016-0267-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 06/14/2016] [Indexed: 11/25/2022]
Abstract
Annulus tension (AT) is defined as leaflet tension per unit length of the annulus circumference. AT was investigated to understand tricuspid valve (TV) annulus mechanics. Ten porcine TVs were mounted on a right ventricle rig with an annulus plate to simulate TV closure. The TVs were mounted on the annulus plate in a normal and dilated TV annulus sizes, and closed under transvalvular pressure of 40 mmHg with the annulus held peripherally by wires. Anterior papillary muscle (PM) and septal PM were displaced in the dilated annulus. Wire forces were measured, and ATs (N/m) were calculated. Clover repair was performed in the dilated TV state subsequently, and AT was calculated again. A one-way ANOVA and Tukey's HSD test were used to test significances between the different TV states along each annulus segment with p < 0.05. Average ATs for the normal annulus, dilated annulus, and clover repair were 10.75 ± 1.87, 28.81 ± 10.51, and 26.93 ± 11.44 N/m, respectively. Septal annulus segments had the highest ATs when compared to the other segments. For the clover repair, there were no significant changes in AT values. ATs and leaflet forces increased roughly 3-4 times with annulus dilation. AT decelerates annulus dilation as previously shown in the mitral valve. Clover repair does not prevent further annulus dilation by AT change and should be accompanied by annuloplasty. AT improves annulus contraction during a cardiac cycle and should be considered when designing annuloplasty in the future.
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Affiliation(s)
- Avik Basu
- Department of Mechanical Engineering, Texas Tech University, 2703 7th street, PO Box 41021, Lubbock, TX, 79409-1021, USA
| | - Zhaoming He
- Department of Mechanical Engineering, Texas Tech University, 2703 7th street, PO Box 41021, Lubbock, TX, 79409-1021, USA. .,Research Center of Fluid Machinery Engineering & Technology, Jiangsu University, Zhenjiang, Jiangsu, 212013, People's Republic of China.
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9
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Bark DL, Dasi LP. The Impact of Fluid Inertia on In Vivo Estimation of Mitral Valve Leaflet Constitutive Properties and Mechanics. Ann Biomed Eng 2016; 44:1425-35. [PMID: 26416720 PMCID: PMC4809800 DOI: 10.1007/s10439-015-1463-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/15/2015] [Indexed: 11/24/2022]
Abstract
We examine the influence of the added mass effect (fluid inertia) on mitral valve leaflet stress during isovolumetric phases. To study this effect, oscillating flow is applied to a flexible membrane at various frequencies to control inertia. Resulting membrane strain is calculated through a three-dimensional reconstruction of markers from stereo images. To investigate the effect in vivo, the analysis is repeated on a published dataset for an ovine mitral valve (Journal of Biomechanics 42(16): 2697-2701). The membrane experiment demonstrates that the relationship between pressure and strain must be corrected with a fluid inertia term if the ratio of inertia to pressure differential approaches 1. In the mitral valve, this ratio reaches 0.7 during isovolumetric contraction for an acceleration of 6 m/s(2). Acceleration is reduced by 72% during isovolumetric relaxation. Fluid acceleration also varies along the leaflet during isovolumetric phases, resulting in spatial variations in stress. These results demonstrate that fluid inertia may be the source of the temporally and spatially varying stiffness measurements previously seen through inverse finite element analysis of in vivo data during isovolumetric phases. This study demonstrates that there is a need to account for added mass effects when analyzing in vivo constitutive relationships of heart valves.
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Affiliation(s)
- David L. Bark
- Colorado State University, School of Mechanical Engineering, Fort Collins, CO, United States
| | - Lakshmi P. Dasi
- Colorado State University, School of Mechanical Engineering, Fort Collins, CO, United States
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10
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Pierce EL, Siefert AW, Paul DM, Wells SK, Bloodworth CH, Takebayashi S, Aoki C, Jensen MO, Gillespie MJ, Gorman RC, Gorman JH, Yoganathan AP. How Local Annular Force and Collagen Density Govern Mitral Annuloplasty Ring Dehiscence Risk. Ann Thorac Surg 2016; 102:518-26. [PMID: 27133454 DOI: 10.1016/j.athoracsur.2016.01.107] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 11/28/2015] [Accepted: 01/28/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Annuloplasty ring dehiscence is a well described mode of mitral valve repair failure. Defining the mechanisms underlying dehiscence may facilitate its prevention. METHODS Factors that govern suture dehiscence were examined with an ovine model. After undersized ring annuloplasty in live animals (n = 5), cyclic force (FC) that acts on sutures during cardiac contraction was measured with custom transducers. FC was measured at ten suture positions, throughout cardiac cycles with peak left ventricular pressure (LVPmax) of 100, 125, and 150 mm Hg. Suture pullout testing was conducted on explanted mitral annuli (n = 12) to determine suture holding strength at each position. Finally, relative collagen density differences at suture sites around the annulus were assessed by two-photon excitation fluoroscopy. RESULTS Anterior FC exceeded posterior FC at each LVPmax (eg, 2.8 ± 1.3 N versus 1.8 ± 1.2 N at LVPmax = 125 mm Hg, p < 0.01). Anterior holding strength exceeded posterior holding strength (6.4 ± 3.6 N versus 3.9 ± 1.6 N, p < 0.0001). On the basis of FC at LVPmax of 150 mm Hg, margin of safety before suture pullout was vastly higher between the trigones (exclusive) versus elsewhere (4.8 ± 0.9 N versus 1.9 ± 0.5 N, p < 0.001). Margin of safety exhibited strong correlation to collagen density (R(2) = 0.947). CONCLUSIONS Despite lower cyclic loading on posterior sutures, the weaker posterior mitral annular tissue creates higher risk of dehiscence, apparently because of reduced collagen content. Sutures placed atop the trigones are less secure than predicted, because of a combination of reduced collagen and higher overall rigidity in this region. These findings highlight the inter-trigonal tissue as the superior anchor and have implications on the design and implantation techniques for next-generation mitral prostheses.
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Affiliation(s)
- Eric L Pierce
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Andrew W Siefert
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Deborah M Paul
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Sarah K Wells
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Charles H Bloodworth
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Satoshi Takebayashi
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chikashi Aoki
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Morten O Jensen
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Matthew J Gillespie
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Robert C Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph H Gorman
- Gorman Cardiovascular Research Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ajit P Yoganathan
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
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11
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Bhattacharya S, Pham T, He Z, Sun W. Tension to passively cinch the mitral annulus through coronary sinus access: an ex vivo study in ovine model. J Biomech 2014; 47:1382-8. [PMID: 24607007 DOI: 10.1016/j.jbiomech.2014.01.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The transcatheter mitral valve repair (TMVR) technique utilizes a stent to cinch a segment of the mitral annulus (MA) and reduces mitral regurgitation. The cinching mechanism results in reduction of the septal-lateral distance. However, the mechanism has not been characterized completely. In this study, a method was developed to quantify the relation between cinching tension and MA area in an ex vivo ovine model. METHOD The cinching tension was measured from a suture inserted within the coronary sinus (CS) vessel with one end tied to the distal end of the vessel and the other end exited to the CS ostium where it was attached to a force transducer on a linear stage. The cinching tension, MA area, septal-lateral (S-L) and commissure-commissure (C-C) diameters and leakage was simultaneously measured in normal and dilated condition, under a hydrostatic left ventricular pressure of 90 mm Hg. RESULTS The MA area was increased up to 22.8% after MA dilation. A mean tension of 2.1 ± 0.5 N reduced the MA area by 21.3 ± 5.6% and S-L diameter by 24.2 ± 5.3%. Thus, leakage was improved by 51.7 ± 16.2% following restoration of normal MA geometry. CONCLUSION The cinching tension generated by the suture acts as a compensation force in MA reduction, implying the maximum tension needed to be generated by annuloplasty device to restore normal annular size. The relationship between cinching tension and the corresponding MA geometry will contribute to the development of future TMVR devices and understanding of myocardial contraction function.
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Affiliation(s)
- Shamik Bhattacharya
- Tissue Mechanics Laboratory Biomedical Engineering Program and Department of Mechanical Engineering University of Connecticut, Storrs, CT 06269, United States
| | - Thuy Pham
- Tissue Mechanics Laboratory Biomedical Engineering Program and Department of Mechanical Engineering University of Connecticut, Storrs, CT 06269, United States
| | - Zhaoming He
- Department of Mechanical Engineering Texas Tech University, Lubbock, TX 79409, United States
| | - Wei Sun
- Tissue Mechanics Laboratory Biomedical Engineering Program and Department of Mechanical Engineering University of Connecticut, Storrs, CT 06269, United States.
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12
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Gunning GM, Murphy BP. Determination of the tensile mechanical properties of the segmented mitral valve annulus. J Biomech 2014; 47:334-40. [DOI: 10.1016/j.jbiomech.2013.11.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/26/2013] [Accepted: 11/21/2013] [Indexed: 10/25/2022]
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13
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Bhattacharya S, He Z. Annulus tension of the prolapsed mitral valve corrected by edge-to-edge repair. J Biomech 2011; 45:562-8. [PMID: 22153221 DOI: 10.1016/j.jbiomech.2011.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 11/06/2011] [Accepted: 11/09/2011] [Indexed: 11/26/2022]
Abstract
BACKGROUND Mitral valve (MV) performance after edge-to-edge repair (ETER) without ring annuloplasty is suboptimal. ETER efficacy needs to be evaluated from annulus tension (AT) of a prolapsed MV corrected by ETER to understand annular dilatation. METHODS Ten porcine MVs were harvested and mounted on a MV closure test rig. The MV annulus tissue rested on top of a saddle-shaped plastic ring on which the annulus could slide freely. The annulus was held by strings in the periphery during MV closure under a hydrostatic trans-mitral pressure. String tensions were measured and further divided by string spacing to obtain AT. The MVs were then prolapsed by shifting split papillary muscles to simulate mono-leaflet prolapse due to elongation of chords, which insert into a single leaflet. Last, MV prolapse was corrected by ETER applied in the central leaflet region and AT was measured. RESULTS AT in both anterior and posterior leaflet prolapse corrected by ETER was less than that of normal MVs. AT in the anterior leaflet prolapse corrected by ETER was less than that in the posterior leaflet prolapse corrected by ETER. CONCLUSION ETER does not restore the normal AT and therefore leads potential of annular dilatation. The anterior leaflet prolapse has a greater potential of annular dilatation than the posterior leaflet prolapse after ETER. Annuloplasty is recommended to maintain long-term ETER efficacy.
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Affiliation(s)
- Shamik Bhattacharya
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA
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Niemann M, Liu D, Hu K, Herrmann S, Breunig F, Strotmann J, Störk S, Voelker W, Ertl G, Wanner C, Weidemann F. Prominent papillary muscles in Fabry disease: a diagnostic marker? ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:37-43. [PMID: 21084151 DOI: 10.1016/j.ultrasmedbio.2010.10.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 09/02/2010] [Accepted: 10/14/2010] [Indexed: 05/30/2023]
Abstract
Fabry disease is often linked with a prominent papillary muscle. It remains unknown whether this sign could be used as a diagnostic marker to screen for Fabry patients. Standard echo was performed in 101 consecutive patients with concentric left ventricular (LV) hypertrophy (28 Fabry, 30 Friedreich, 34 isolated arterial hypertension, 9 amyloidosis) and 50 healthy controls. In addition, the areas of both papillary muscles, as well as the LV endocardial circumference, were manually traced in short axis views. A ratio of papillary muscle size to LV circumference was calculated (PM_LV_ratio). The papillary muscle area was positively correlated to LV wall thickness in this cohort (p < 0.0001; r = 0.58). In all patient subgroups, the absolute papillary muscle area was significantly enlarged and the PM_LV_ratio was significantly higher when compared with controls. However, Fabry patients showed a significantly larger absolute papillary muscle area than Friedreich and amyloidosis patients and a higher PM_LV_ratio than hypertensive and amyloidosis patients. Enlarged absolute papillary muscle area was evidenced in 21 (75%), and increased PM_LV_ratio was found in 22 (78%) of 28 Fabry patients. Combining these two parameters yields a sensitivity of 75% and specificity of 86% for diagnosing Fabry disease with LV hypertrophy. Only 10 of 73 non-Fabry patients (14%) (4 Friedreich, 1 amyloidosis, 5 hypertensive) showed an increased absolute papillary muscle area and PM_LV_ratio. In conclusion, this study confirmed the assumption that the prominent papillary muscle could be an echocardiographic marker for detection of Fabry patients with concentric LV hypertrophy.
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Affiliation(s)
- Markus Niemann
- Department of Internal Medicine I/Center of Cardiovascular Disease, University of Wuerzburg, Germany
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Stevanella M, Votta E, Redaelli A. Mitral Valve Finite Element Modeling: Implications of Tissues’ Nonlinear Response and Annular Motion. J Biomech Eng 2009; 131:121010. [DOI: 10.1115/1.4000107] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Finite element modeling represents an established method for the comprehension of the mitral function and for the simulation of interesting clinical scenarios. However, current models still do not include all the key aspects of the real system. We implemented a new structural finite element model that considers (i) an accurate morphological description of the valve, (ii) a description of the tissues’ mechanical properties that accounts for anisotropy and nonlinearity, and (iii) dynamic boundary conditions that mimic annulus and papillary muscles’ contraction. The influence of such contraction on valve biomechanics was assessed by comparing the computed results with the ones obtained through an auxiliary model with fixed annulus and papillary muscles. At the systolic peak, the leaflets’ maximum principal stress contour showed peak values in the anterior leaflet at the strut chordae insertion zone (300 kPa) and near the annulus (200–250 kPa), while much lower values were detected in the posterior leaflet. Both leaflets underwent larger tensile strains in the longitudinal direction, while in the circumferential one the anterior leaflet experienced nominal tensile strains up to 18% and the posterior one experienced compressive strains up to 23% associated with the folding of commissures and paracommissures, consistently with tissue redundancy. The force exerted by papillary muscles at the systolic peak was equal to 4.11 N, mainly borne by marginal chordae (76% of the force). Local reaction forces up to 45 mN were calculated on the annulus, leading to tensions of 89 N/m and 54 N/m for its anterior and posterior tracts, respectively. The comparison with the results of the auxiliary model showed that annular contraction mainly affects the leaflets’ circumferential strains. When it was suppressed, no more compressive strains could be observed and peak strain values were located in the belly of the anterior leaflet. Computational results agree to a great extent with experimental data from literature. They provided insight into some of the features characterizing normal mitral function, such as annular contraction and leaflets’ tissue anisotropy and nonlinearity. Some of the computed results may be useful in the design of surgical devices and techniques. In particular, forces applied on the annulus by the surrounding tissues could be considered as an indication for annular prostheses design.
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Affiliation(s)
- Marco Stevanella
- Department of Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy
| | - Emiliano Votta
- Department of Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy
| | - Alberto Redaelli
- Department of Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy
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