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mechanical valve prostheses

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https://www.readbyqxmd.com/read/28178887/magnesium-presence-prevents-removal-of-antigenic-nuclear-associated-proteins-from-bovine-pericardium-for-heart-valve-engineering
#1
Ailsa Dalgliesh, Zhi Zhao Liu, Leigh Griffiths
Current heart valve prostheses are associated with significant complications including aggressive immune response, limited valve life expectancy, and inability to grow in juvenile patients. Animal derived "tissue" valves undergo glutaraldehyde fixation to mask tissue antigenicity, however chronic immunological responses and associated calcification still commonly occur. A heart valve formed from an unfixed bovine pericardium (BP) extracellular matrix (ECM) scaffold, in which antigenic burden has been eliminated or significantly reduced, has potential to overcome deficiencies of current bio-prostheses...
February 8, 2017: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/28117617/patterns-and-determinants-of-functional-and-absolute-iron-deficiency-in-patients-undergoing-cardiac-rehabilitation-following-heart-surgery
#2
Roberto Tramarin, Valeria Pistuddi, Luigi Maresca, Marco Pavesi, Serenella Castelvecchio, Lorenzo Menicanti, Carlo de Vincentiis, Marco Ranucci
Background Anaemia and iron deficiency are frequent following major surgery. The present study aims to identify the iron deficiency patterns in cardiac surgery patients at their admission to a cardiac rehabilitation programme, and to determine which perioperative risk factor(s) may be associated with functional and absolute iron deficiency. Design This was a retrospective study on prospectively collected data. Methods The patient population included 339 patients. Functional iron deficiency was defined in the presence of transferrin saturation <20% and serum ferritin ≥100 µg/l...
January 1, 2017: European Journal of Preventive Cardiology
https://www.readbyqxmd.com/read/28105540/echocardiographic-assessment-of-long-term-hemodynamic-characteristics-of-mechanical-mitral-valve-prostheses-with-different-mitral-valvular-diseases
#3
Xiliang Zhu, Qian Li, Hong Tang, Xijun Xiao
Mitral stenosis (MS) and mitral insufficiency (MI) have different pre-operative hemodynamic characteristics. However, it is unclear if there are differences in long-term echocardiographic characteristics of MS and MI patients after mechanical mitral valve replacement. This study is to compare long-term echocardiographic results of mechanical mitral valve prostheses between MS and MI patients. From January 2003 to January 2009, a total of 199 consecutive patients were recruited in this study. Patients were classified as group MS (n = 123) and MI (n = 76) according to the manifestation of mitral valvular disease...
January 19, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28088917/effects-of-heart-valve-prostheses-on-phase-contrast-flow-measurements-in-cardiovascular-magnetic-resonance-a-phantom-study
#4
Johanna Richau, Matthias A Dieringer, Julius Traber, Florian von Knobelsdorff-Brenkenhoff, Andreas Greiser, Carsten Schwenke, Jeanette Schulz-Menger
BACKGROUND: Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial. METHODS: Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B0 maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses...
January 16, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28049599/effective-orifice-area-during-exercise-in-bileaflet-mechanical-valve-prostheses
#5
Philippe B Bertrand, Matteo Pettinari, Hélène De Cannière, Herbert Gutermann, Christophe J P Smeets, David Verhaert, Robert A Dion, Pascal Verdonck, Pieter M Vandervoort
BACKGROUND: The aims of this study were to investigate the evolution of the transprosthetic pressure gradient and effective orifice area (EOA) during dynamic bicycle exercise in bileaflet mechanical heart valves and to explore the relationship with exercise capacity. METHODS: Patients with bileaflet aortic valve replacement (n = 23) and mitral valve replacement (MVR; n = 16) prospectively underwent symptom-limited supine bicycle exercise testing with Doppler echocardiography and respiratory gas analysis...
December 31, 2016: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/28007066/valve-sparing-aortic-root-replacement-in-pediatric-patients-lessons-learned-over-two-decades
#6
REVIEW
Luca A Vricella, Duke E Cameron
Valve-sparing aortic root replacement has been utilized in children with aneurysms of the proximal aorta as a valid alternative to composite mechanical or biologic prostheses. While the majority of pediatric patients with aortic root aneurysms have various forms of connective tissue disorders, other diagnostic groups have emerged, such as patients with various forms of congenital heart disease and non-syndromic thoracic aortic aneurysms. We present our experience with valve-sparing procedures in pediatric patients, highlighting the technical aspects of the operation as well as some of the pitfalls and complications we have encountered over the last two decades...
January 2017: Seminars in Thoracic and Cardiovascular Surgery. Pediatric Cardiac Surgery Annual
https://www.readbyqxmd.com/read/27989074/excellence-and-durability-a-normally-functioning-bj%C3%A3-%C3%A2-rk-shiley-flat-disc-prosthesis-42-years-post-implantation
#7
Armaan Shaikh, A Jamil Tajik
Mechanical heart valves have been used worldwide for more than 60 years. While the composition and design of the valves, and the surgical techniques employed to implant them, have changed and advanced over that time, some of the earlier mechanical heart valves showed such great durability that they are still functioning in patients today. One of the most often-used and long-lasting mechanical prostheses was the Björk-Shiley heart valve. While many versions of this valve were used during its 25 years of production, the most durable was the Björk-Shiley flat-disc valve...
March 2016: Journal of Heart Valve Disease
https://www.readbyqxmd.com/read/27989046/valve-replacement-in-patients-with-carcinoid-heart-disease-choosing-the-right-valve-at-the-right-time
#8
Amit Korach, Simona Grozinsky-Glasberg, Joseph Atlan, Abeer Dabah, Karine Atlan, Ehud Rudis, Amir Elami, David J Gross, Michael J Reardon, Oz M Shapira
BACKGROUND: The prosthetic valve of choice in patients with carcinoid valve disease (CVD) remains controversial due to the limited life expectancy of patients with advanced-stage neuroendocrine tumors (NETs) on the one hand, and concerns regarding structural valve deterioration (SVD) on the other hand. METHODS: The records of 17 patients (11 females, seven males; mean age 65 ± 11 years; undergoing 18 operations) with primarily right heart failure due to CVD were reviewed...
May 2016: Journal of Heart Valve Disease
https://www.readbyqxmd.com/read/27957643/should-the-automatic-exposure-control-system-of-ct-be-disabled-when-scanning-patients-with-endoaortic-stents-or-mechanical-heart-valves-a-phantom-study
#9
Giovanni Di Leo, Chiara Spadavecchia, Moreno Zanardo, Francesco Secchi, Ivan Veronese, Marie Claire Cantone, Francesco Sardanelli
OBJECTIVES: To estimate the impact of endoaortic stents/mechanical heart valves on the output of an automatic exposure control (AEC) system and CT radiation dose. METHODS: In this phantom study, seven stents and two valves were scanned with varying tube voltage (80/100/120 kVp), AEC activation (enabled/disabled) and prosthesis (present/absent), for a total of 540 scans. For each prosthesis, the dose-length product (DLP) was compared between scans with the AEC enabled and disabled...
December 12, 2016: European Radiology
https://www.readbyqxmd.com/read/27936430/collagen-tissue-treated-with-chitosan-solution-in-h2o-co2-mixtures-influence-of-clathrates-hydrates-on-the-structure-and-mechanical-properties
#10
Ivan S Chaschin, Natalia P Bakuleva, Timofei E Grigoriev, Sergey V Krasheninnikov, Lev N Nikitin
A mixture of water/carbon dioxide is a "green" perspective solvent from the viewpoint of biomedical applications. Clathrate hydrates are formed this solvent under certain conditions and a very interesting question is the impact of clathrates hydrates on the structure and properties of bovine pericardium, which is used in biomedicine, in particular as a main part of biological heart valve prostheses. The aim of the present work is to investigate the influence of clathrates on the structure and mechanical properties of the collagen tissue treated with chitosan in H2O/CO2 mixtures under pressure 3...
November 30, 2016: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/27899293/valvular-regurgitation-after-implantation-of-prostheses-secured-with-cor-knot-automated-fasteners
#11
Alexander A Brescia, Steven F Bolling, Himanshu J Patel
Valvular regurgitation is a recognized complication of aortic and mitral valve procedures, with paravalvular leak the primary mechanism and transvalvular less common. The Cor-knot automated fastener (LSI SOLUTIONS, Victor, NY, USA) has been shown to be a safe, viable alternative to knot pushers or manual tying for use in these procedures. Here we present two cases in which Cor-Knot fastener orientation appeared to result in transvalvular regurgitation necessitating redo operation. With adjunctive use of Cor-Knot devices, fastener orientation relative to valve geometry must be assessed for optimal results...
November 26, 2016: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/27889349/acquired-aseptic-intracardiac-shunts-following-transcatheter-aortic-valve%C3%A2-replacement-a%C3%A2-systematic-review
#12
Paol Rojas, Ignacio J Amat-Santos, Carlos Cortés, Javier Castrodeza, Javier Tobar, Rishi Puri, Teresa Sevilla, Silvio Vera, Luis H Varela-Falcón, Jose Luis Zunzunegui, Itziar Gómez, Josep Rodés-Cabau, José A San Román
OBJECTIVES: The aim of this study was to describe the incidence, mechanisms, features, and management of aseptic intracardiac shunts (AICS). BACKGROUND: AICS following transcatheter aortic valve replacement (TAVR) are an uncommon and barely described complication. METHODS: A systematic review was performed of all published cases of AICS following TAVR, and the incidence, predictors, main features, management, and related outcomes were analyzed...
December 26, 2016: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/27834758/current-status-of-tissue-engineering-heart-valve
#13
Toshiharu Shinoka, Hideki Miyachi
The development of surgically implantable heart valve prostheses has contributed to improved outcomes in patients with cardiovascular disease. However, there are drawbacks, such as risk of infection and lack of growth potential. Tissue-engineered heart valve (TEHV) holds great promise to address these drawbacks as the ideal TEHV is easily implanted, biocompatible, non-thrombogenic, durable, degradable, and ultimately remodels into native-like tissue. In general, three main components used in creating a tissue-engineered construct are (1) a scaffold material, (2) a cell type for seeding the scaffold, and (3) a subsequent remodeling process driven by cell accumulation and proliferation, and/or biochemical and mechanical signaling...
November 2016: World Journal for Pediatric & Congenital Heart Surgery
https://www.readbyqxmd.com/read/27798318/comparing-usual-care-with-a-warfarin-initiation-protocol-after-mechanical-heart-valve-replacement
#14
Gregory Roberts, Rasha Razooqi, Stephen Quinn
BACKGROUND: The immediate postoperative warfarin sensitivity for patients receiving heart valve prostheses is increased. Established warfarin initiation protocols may lack clinical applicability, resulting in dosing based on clinical judgment. OBJECTIVE: To compare current practice for warfarin initiation with a known warfarin initiation protocol, with doses proportionally reduced to account for the increased postoperative sensitivity. METHODS: We compared the Mechanical Heart Valve Warfarin Initiation Protocol (Protocol group) with current practice (clinical judgment-Empirical group) for patients receiving mechanical heart valves in an observational before-and-after format...
October 25, 2016: Annals of Pharmacotherapy
https://www.readbyqxmd.com/read/27780149/nanofibrous-bioengineered-heart-valve-application-in-paediatric-medicine
#15
REVIEW
Mehrdad Namdari, Ali Eatemadi
Heart valves are currently under thorough investigation in tissue engineering (TE) research. Mechanical and biological heart valve prostheses which are recently used have several shortcomings. While allogenic and xenogenic biological prostheses are related to graft rejection, degeneration and thrombosis, resulting in a high rate of reoperation. Mechanical prostheses on the other hand are based on metallic, carbon, and polymeric components, and require continuous treatment with anticoagulant, which result in adverse reactions, e...
December 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/27666180/anticoagulation-after-heart-valve-replacement-or-transcatheter-valve-implantation
#16
Anthony P Carnicelli, Patrick T O'Gara, Robert P Giugliano
Valvular heart disease is prevalent and represents a significant contributor to cardiac morbidity and mortality. Several options for valve replacement exist, including surgical replacement and transcatheter valve implantation. Prosthetic valves lead to increased risk of thromboembolic disease; therefore, antithrombotic therapy after valve replacement is indicated. For patients with mechanical prostheses, indefinite vitamin K antagonist and antiplatelet therapy are the mainstays of treatment. There is no consensus regarding optimal antithrombotic therapy after bioprosthetic valve replacement, although vitamin K antagonist therapy of varying duration in addition to antiplatelet therapy is recommended by guidelines...
August 13, 2016: American Journal of Cardiology
https://www.readbyqxmd.com/read/27636399/which-type-of-valve-should-we-use-in-tricuspid-position-long-term-comparison-between-mechanical-and-biological-valves
#17
Ana Redondo Palacios, José López Menéndez, Javier Miguelena Hycka, Miren Martín García, Laura Varela Barca, Andrea Ferreiro Marzal, Rafael Muñoz Pérez, Enrique Oliva De Anquín, Ignacio García Andrade, Tomasa Centella Hernández, Daniel Celemín Canorea, Jorge Rodríguez-Roda Stuart
BACKGROUND: Nowadays, Tricuspid valve replacement (TVR) is much less common than aortic or mitral valve replacement, since repair is almost always preferable. Prosthetic tricuspid valves are associated with high mortality and morbidity, mostly due to thrombotic or hemorrhagic events. Nevertheless, there is lack of evidence of which is the optimal type of valve (biological versus mechanical) in tricuspid position. METHODS: We analysed all the patients who underwent TVR in our Institution, from 2005 to 2015...
September 16, 2016: Journal of Cardiovascular Surgery
https://www.readbyqxmd.com/read/27583703/adherence-of-staphylococcus-aureus-to-dyneema-purity%C3%A2-patches-and-to-clinically-used-cardiovascular-prostheses
#18
Amir Basir, Paul Gründeman, Frans Moll, Joost van Herwaarden, Gerard Pasterkamp, Reindert Nijland
Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecular-weight polyethylene. Dyneema Purity® fibers are very thin, flexible, resistant to fatigue and abrasion, and have high strength. S. aureus adherence to Dyneema Purity® was tested and compared with currently used cardiovascular prostheses...
2016: PloS One
https://www.readbyqxmd.com/read/27573761/effects-of-leaflet-design-on-transvalvular-gradients-of-bioprosthetic-heart-valves
#19
Yaghoub Dabiri, Janet Ronsky, Imtiaz Ali, Ameen Basha, Alisha Bhanji, Kishan Narine
Bioprosthetic aortic valves (BAVs) are becoming the prostheses of choice in heart valve replacement. The objective of this paper is to assess the effects of leaflet geometry on the mechanics and hemodynamics of BAVs in a fluid structure interaction model. The curvature and angle of leaflets were varied in 10 case studies whereby the following design parameters were altered: a circular arch, a line, and a parabola for the radial curvature, and a circular arch, a spline, and a parabola for the circumferential curvature...
December 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27521817/experimental-investigations-on-the-fluid-mechanics-of-an-electrospun-heart-valve-by-means-of-particle-image-velocimetry
#20
Costantino Del Gaudio, Pier Luca Gasbarroni, Giovanni Paolo Romano
End-stage failing heart valves are currently replaced by mechanical or biological prostheses. Both types positively contribute to restore the physiological function of native valves, but a number of drawbacks limits the expected performances. In order to improve the outcome, tissue engineering can offer an alternative approach to design and fabricate innovative heart valves capable to support the requested function and to promote the formation of a novel, viable and correctly operating physiological structure...
December 2016: Journal of the Mechanical Behavior of Biomedical Materials
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