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Mechanical properties of mitral valve

Iliona Malaspinas, Ferenc Petak, Lionel Chok, Anne Perrin, Anne-Laure Martin, Maurice Beghetti, Walid Habre
OBJECTIVE: To assess the profile of changes in airway and respiratory tissue mechanics within a follow-up study performed in children with mitral valve disease, before and after surgical valve repair. DESIGN: Perioperative measurements in a prospective, consecutive cross-sectional study. SETTING: University hospital, tertiary care teaching hospital PARTICIPANTS: The study comprised 24 children with congenital or post-rheumatic mitral valve insufficiency...
October 2016: Journal of Cardiothoracic and Vascular Anesthesia
Philippe Primo Caimmi, Maurizio Sabbatini, Luca Fusaro, Alessia Borrone, Mario Cannas
BACKGROUND AND AIM OF THE STUDY: We investigated the dimensional and mechanical properties of polyetetrafluorene (ePTFE) sutures used as artificial chordae during mitral valve repair. METHODS: Mechanical properties of ePTFE synthetic chordae tendineae were tested with a servo hydraulic testing machine. Several different lengths from 2 to 14 cm were studied under both single and multiple mechanical traction. RESULTS: The mechanical behavior of artificial chordae reveals that three centimeters is the length over which we observe a significant increase in stiffness...
August 2016: Journal of Cardiac Surgery
Keping Zuo, Thuy Pham, Kewei Li, Caitlin Martin, Zhaoming He, Wei Sun
The mitral valve (MV) is a highly complex cardiac valve consisting of an annulus, anterior and posterior leaflets, chordae tendineae (chords) and two papillary muscles. The chordae tendineae mechanics play a pivotal role in proper MV function: the chords help maintain proper leaflet coaptation and rupture of the chordae tendineae due to disease or aging can lead to mitral valve insufficiency. Therefore, the aim of this study was to characterize the mechanical properties of aged human and ovine mitral chordae tendineae...
September 2016: Journal of the Mechanical Behavior of Biomedical Materials
Nathali Cordeiro Pinto, M Cristina Chavantes, Denise Zezell, Alessandro Deana, Carolina Benetti, Rodrigo Labat Marcos, Luciana Almeida Lopes, Rodrigo A B Lopes Martins, Vera Demarchi Aiello, Fabio Biscegli Jatene, Pablo M A Pomerantzeff
Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation)...
August 2016: Lasers in Medical Science
Tomohiro Otani, Abdullah Al-Issa, Amir Pourmorteza, Elliot R McVeigh, Shigeo Wada, Hiroshi Ashikaga
Atrial fibrillation (AF), the most common human arrhythmia, is a marker of an increased risk of embolic stroke. However, recent studies suggest that AF may not be mechanistically responsible for the stroke events. An alternative explanation for the mechanism of intracardiac thrombosis and stroke in patients with AF is structural remodeling of the left atrium (LA). Nevertheless, a mechanistic link between LA structural remodeling and intracardiac thrombosis is unclear, because there is no clinically feasible methodology to evaluate the complex relationship between these two phenomena in individual patients...
March 11, 2016: Annals of Biomedical Engineering
Nicholas Roberts, Lucrezia Morticelli, Zhongmin Jin, Eileen Ingham, Sotirios Korossis
The aim of this study was to investigate the regional and directional differences in the biomechanics and histoarchitecture of the porcine mitral valve (MV) apparatus, with a view to tailoring tissue-engineered constructs for MV repair. The anterior leaflet displayed the largest directional anisotropy with significantly higher strength in the circumferential direction compared to the posterior leaflet. The histological results indicated that this was due to the circumferential alignment of the collagen fibers...
August 16, 2016: Journal of Biomechanics
Joost Lodder, Gijsbertus J Verkerke, Ben Jm Delemarre, Dimitra Dodou
A number of studies have investigated the morphological and mechanical properties of the chordae tendineae of the mitral valve, providing comparisons between basal, marginal, and strut chordae and between chordae at the anterior and posterior leaflets. This study contributes to the literature by comparing the failure load of the chordae tendineae attached to the three posterior leaflet scallops, the anterolateral scallop (P1), middle scallop (P2), and posteromedial scallop (P3) of the mitral valve. In all, 140 chordae isolated from 23 porcine hearts were tested...
February 2016: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
Francesco Sturla, Alberto Redaelli, Giovanni Puppini, Francesco Onorati, Giuseppe Faggian, Emiliano Votta
Mitral regurgitation is the most prevalent heart valve disease in the western population. When severe, it requires surgical treatment, repair being the preferred option. The edge-to-edge repair technique treats mitral regurgitation by suturing the leaflets together and creating a double-orifice valve. Due to its relative simplicity and versatility, it has become progressively more widespread. Recently, its percutaneous version has become feasible, and has raised interest thanks to the positive results of the Mitraclip(®) device...
June 2015: Cardiovascular Engineering and Technology
Federico Domenichini, Gianni Pedrizzetti
The vortex formation process inside the left ventricle is intrinsically connected to the dynamics of the mitral leaflets while they interact with the flow crossing the valve during diastole. The description of the dynamics of a natural mitral valve still represents a challenging issue, especially because its material properties are not measurable in vivo. Medical imaging can provide some indications about the geometry of the valve, but not about its mechanical properties. In this work, we introduce a parametric model of the mitral valve geometry, whose motion is described in the asymptotic limit under the assumption that it moves with the flow, without any additional resistance other than that given by its shape, and without the need to specify its material properties...
June 2015: Cardiovascular Engineering and Technology
Maryam Eslami, Gholamreza Javadi, Nasser Agdami, Mohammad Ali Shokrgozar
OBJECTIVE: The incidence of heart valve disease is increasing worldwide and the number of heart valve replacements is expected to increase in the future. By mimicking the main tissue structures and properties of heart valve, tissue engineering offers new options for the replacements. Applying an appropriate scaffold in fabricating tissue-engineered heart valves (TEHVs) is of importance since it affects the secretion of the main extracellular matrix (ECM) components, collagen 1 and elastin, which are crucial in providing the proper mechanical properties of TEHVs...
2015: Cell Journal
David L Bark, Lakshmi P Dasi
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...
May 2016: Annals of Biomedical Engineering
Caitlin M Pierlot, Andrew D Moeller, J Michael Lee, Sarah M Wells
Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows...
November 2015: American Journal of Physiology. Heart and Circulatory Physiology
Elizabeth H Stephens, Patrick S Connell, Monica M Fahrenholtz, Tomasz A Timek, George T Daughters, Joyce J Kuo, Aaron M Patton, Neil B Ingels, D Craig Miller, K Jane Grande-Allen
To determine how extracellular matrix and contractile valvular cells contribute to the heterogeneous motion and strain across the mitral valve (MV) during the cardiac cycle, regional MV material properties, matrix composition, matrix turnover, and cell phenotype were related to regional leaflet strain. Radiopaque markers were implanted into 14 sheep to delineate the septal (SEPT), lateral (LAT), and anterior and posterior commissural leaflets (ANT-C, POST-C). Videofluoroscopy imaging was used to calculate radial and circumferential strains...
June 2015: Cardiovascular Engineering and Technology
Elizabeth H Stephens, Monica M Fahrenholtz, Patrick S Connell, Tomasz A Timek, George T Daughters, Joyce J Kuo, Aaron M Patton, Neil B Ingels, D Craig Miller, K Jane Grande-Allen
PURPOSE: Regional heterogeneity in mitral annular contraction, which is generally ascribed to the fibrous vs. muscular annular composition, ensures proper leaflet motion and timing of coaptation. It is unknown whether the fibroblast-like cells in the annulus modulate this heterogeneity, even though valvular interstitial cells (VICs) can be mechanically "activated." METHODS: Fourteen sheep underwent implantation of radiopaque markers around the mitral annulus defining four segments: septal (SEPT), lateral (LAT), and anterior (ANT-C) and posterior (POST-C) commissures...
June 2015: Cardiovascular Engineering and Technology
Brian Baillargeon, Ivan Costa, Joseph R Leach, Lik Chuan Lee, Martin Genet, Arnaud Toutain, Jonathan F Wenk, Manuel K Rausch, Nuno Rebelo, Gabriel Acevedo-Bolton, Ellen Kuhl, Jose L Navia, Julius M Guccione
Ischemic mitral regurgitation is associated with substantial risk of death. We sought to: (1) detail significant recent improvements to the Dassault Systèmes human cardiac function simulator (HCFS); (2) use the HCFS to simulate normal cardiac function as well as pathologic function in the setting of posterior left ventricular (LV) papillary muscle infarction; and (3) debut our novel device for correction of ischemic mitral regurgitation. We synthesized two recent studies of human myocardial mechanics. The first study presented the robust and integrative finite element HCFS...
June 2015: Cardiovascular Engineering and Technology
Flavia Carneiro, Boudewijn Pt Kruithof, Kanthesh Balani, Arvind Agarwal, Vinciane Gaussin, Lidia Kos
Heart valves are complex structures composed of organized layers of extracellular matrix, and interstitial and overlying endothelial cells. In this article, we present the specific localization of a population of melanocytes within the murine heart valves at ages important for their post-natal development. In all stages analyzed in our study, melanocytes were found in high numbers populating the atrial aspect of the tricuspid and mitral leaflets. The pulmonary valve did not present melanocytes. To characterize a putative role for the valve melanocytes, the dynamic nanomechanical properties of tricuspid leaftets containing large numbers or no melanocytes were measured...
2015: Journal of Long-term Effects of Medical Implants
Chung-Hao Lee, Christopher A Carruthers, Salma Ayoub, Robert C Gorman, Joseph H Gorman, Michael S Sacks
Within each of the four layers of mitral valve (MV) leaflet tissues there resides a heterogeneous population of interstitial cells that maintain the structural integrity of the MV tissue via protein biosynthesis and enzymatic degradation. There is increasing evidence that tissue stress-induced MV interstitial cell (MVIC) deformations can have deleterious effects on their biosynthetic states that are potentially related to the reduction of tissue-level maintenance and to subsequent organ-level failure. To better understand the interrelationships between tissue-level loading and cellular responses, we developed the following integrated experimental-computational approach...
May 21, 2015: Journal of Theoretical Biology
Pavel Iablonskii, Serghei Cebotari, Igor Tudorache, Marisa Granados, Lucrezia Morticelli, Tobias Goecke, Norman Klein, Sotirios Korossis, Andres Hilfiker, Axel Haverich
OBJECTIVES: The present study aimed at developing tissue-engineered mitral valves based on cell-free ovine mitral allografts. METHODS: The ovine mitral valves (OMVs) (n = 46) were harvested in the local slaughter house. They were decellularized using detergent solutions and DNase. The effectiveness of decellularization was assessed by histological (haematoxylin-eosin, Movat's pentachrome) and immunofluorescent staining (for DNA and α-Gal), and DNA-quantification...
June 2015: Interactive Cardiovascular and Thoracic Surgery
Elena Galli, Patrizio Lancellotti, Partho P Sengupta, Erwan Donal
The assessment of myocardial function in the context of valvular heart disease remains highly challenging. The myocardium deforms simultaneously in 3 dimensions, and global left ventricular (LV) function parameters such as volume and ejection fraction may remain compensated despite the changes in myocardial deformation properties. Current guidelines recommend valve replacement/repair in the presence of symptoms or reduced LV ejection fraction, but the resolution of symptoms or recovery of LV function post-surgery may not be reliably predicted...
November 2014: JACC. Cardiovascular Imaging
Sanjay Dixit, Amit Mehrotra
No abstract text is available yet for this article.
February 2015: Journal of Cardiovascular Electrophysiology
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