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mechanical aortic valve

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https://www.readbyqxmd.com/read/28213846/fixation-of-bovine-pericardium-based-tissue-biomaterial-with-irreversible-chemistry-improves-biochemical-and-biomechanical-properties
#1
H Tam, W Zhang, D Infante, N Parchment, M Sacks, N Vyavahare
Bioprosthetic heart valves (BHVs), derived from glutaraldehyde crosslinked (GLUT) porcine aortic valve leaflets or bovine pericardium (BP), are used to replace defective heart valves. However, valve failure can occur within 12-15 years due to calcification and/or progressive structural degeneration. We present a novel fabrication method that utilizes carbodiimide, neomycin trisulfate, and pentagalloyl glucose crosslinking chemistry (TRI) to better stabilize the extracellular matrix of BP. We demonstrate that TRI-treated BP is more compliant than GLUT-treated BP...
February 17, 2017: Journal of Cardiovascular Translational Research
https://www.readbyqxmd.com/read/28209171/integrated-strategy-for-in-vitro-characterization-of-a-bileaflet-mechanical-aortic-valve
#2
Francesca Maria Susin, Stefania Espa, Riccardo Toninato, Stefania Fortini, Giorgio Querzoli
BACKGROUND: Haemodynamic performance of heart valve prosthesis can be defined as its ability to fully open and completely close during the cardiac cycle, neither overloading heart work nor damaging blood particles when passing through the valve. In this perspective, global and local flow parameters, valve dynamics and blood damage safety of the prosthesis, as well as their mutual interactions, have all to be accounted for when assessing the device functionality. Even though all these issues have been and continue to be widely investigated, they are not usually studied through an integrated approach yet, i...
February 16, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28198528/the-expression-of-inhibitor-of-nuclear-factor-kappa-b-kinase-epsilon-ikk%C3%AE%C2%B5-in-human-aortic-aneurysm
#3
Leiyang Zhang, Lei Wang, Wen Chen, Yueyue Xu, Liming Wang, Reinard Iskandar, Yifei Wang, Xin Chen
BACKGROUND: Aortic aneurysm (AA) is one of the most common causes of sudden death among elderly people. Although AA can be detected by non-invasive imaging techniques, there are no pharmacological treatments currently available to prevent progression at any stage of the disease. In this study we will explore the expression of IKKε in AA and its potential underlying molecular mechanism in AA. Material s and methods: Human aortic tissue was taken from 14 patients who underwent surgical repair of AA for the AA group and another 11 patients with normal aorta who underwent aortic valve replacement surgery for the control group...
February 15, 2017: Folia Morphologica (Warsz)
https://www.readbyqxmd.com/read/28194824/left-intraventricular-pressure-gradients-improvement-after-aortic-valve-replacement-in-aortic-stenosis-patients
#4
Miguel Guerra, Pedro Mendes-Ferreira, Rui Adão, Eulália Pereira, Manuela Vieira, André P Lourenço, Carmen Brás-Silva, Pedro Bastos, Luís Vouga, Adelino F Leite-Moreira
The present study was conducted to characterize left intraventicular pressure gradients, a marker of normal cardiac function, in patients with severe aortic stenosis, a condition which interferes with ventricular filling and emptying. In 10 patients (4 male; mean age 71.3 ± 4.8 years old) undergoing aortic valve replacement, 2 high-fidelity pressure catheters were inserted inside the left ventricle cavity through an apical puncture and positioned in the apex and outflow-tract below the aortic valve. Pressures were continuously acquired and gradients were calculated as apical minus outflow-tract pressure, before and immediately after aortic valve replacement...
February 14, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28183712/mechanical-thrombectomy-of-embolised-native-aortic-valve-post-tavi
#5
John Joseph Coughlan, Rob Fleck, Cormac O'Connor, Peter Crean
No abstract text is available yet for this article.
February 9, 2017: BMJ Case Reports
https://www.readbyqxmd.com/read/28179397/dipeptidyl-peptidase-4-induces-aortic-valve-calcification-by-inhibiting-insulin-like-growth-factor-1-signaling-in-valvular-interstitial-cells
#6
Bongkun Choi, Sahmin Lee, Sang-Min Kim, Eun-Jin Lee, Sun Ro Lee, Dae-Hee Kim, Jeong Yoon Jang, Sang-Wook Kang, Ki-Up Lee, Eun-Ju Chang, Jae-Kwan Song
Background -Calcification of the aortic valve leads to increased leaflet stiffness, and consequently to the development of calcific aortic valve disease (CAVD); however, the underlying molecular and cellular mechanisms of calcification remain unclear. Here, we identified that dipeptidyl peptidase-4 (DPP-4, also known as CD26) increases valvular calcification and promotes CAVD progression. Methods -We obtained the aortic valve tissues from humans and murine models (wild type and eNOS(-/-) mice), and cultured the valvular interstitial cells (VICs) and valvular endothelial cells (VECs) from the cusps...
February 8, 2017: Circulation
https://www.readbyqxmd.com/read/28179104/variations-in-structure-of-the-outflow-tract-of-the-human-embryonic-heart-a-new-hypothesis-for-generating-bicuspid-aortic-semilunar-valves
#7
Nadine C Milos, Derek B Nordstrom, Ivano Ongaro, Ava K Chow
Outflow tract development of the heart is complex. The presence, differential growth and interactions of the various tissues through space and time contribute to the final development of the tract. This paper presents a novel interpretation of observations of outflow tract development, in particular of the aortic and pulmonary semilunar valves in embryos from the Shaner Collection at the University of Alberta. Three-dimensional reconstructions assist in the visualization of the spatial relationships of the developing valve tissues...
February 4, 2017: Annals of Anatomy, Anatomischer Anzeiger: Official Organ of the Anatomische Gesellschaft
https://www.readbyqxmd.com/read/28173819/cardiovascular-magnetic-resonance-evaluation-of-symptomatic-severe-aortic-stenosis-association-of-circumferential-myocardial-strain-and-mortality
#8
Tarique Al Musa, Akhlaque Uddin, Peter P Swoboda, Timothy A Fairbairn, Laura E Dobson, Anvesha Singh, Pankaj Garg, Christopher D Steadman, Bara Erhayiem, Ananth Kidambi, David P Ripley, Adam K McDiarmid, Philip Haaf, Daniel J Blackman, Sven Plein, Gerald P McCann, John P Greenwood
BACKGROUND: It is unknown whether circumferential strain is associated with prognosis after treatment of aortic stenosis (AS). We aimed to characterise strain in severe AS, using myocardial tagging cardiovascular magnetic resonance (CMR), prior to and following Transcatheter Aortic Valve Implantation (TAVI) and Surgical Aortic Valve Replacement (SAVR), and determine whether abnormalities in strain were associated with outcome. METHODS: CMR was performed pre- and 6 m post-intervention in 98 patients (52 TAVI, 46 SAVR; 77 ± 8 years) with severe AS...
February 8, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28170357/on-x-valve-the-next-generation-aortic-valve
#9
Rahul Chaudhary, Jalaj Garg, Parasuram Krishnamoorthy, Neeraj Shah, Bruce A Feldman, Matthew W Martinez, Ronald Freudenberger
The On-X valve is a newer generation mechanical bileaflet valve. Its key features include the use of pure pyrolytic carbon (devoid of silicon), a length-to-diameter ratio similar to a native valve, an inlet flared orifice, a leaflet opening up to 90 degrees, a shorter leaflet closing angle, a 2-point leaflet contact, and an actuated pivot. These features have translated into increased strength, improved valve hemodynamics, reduced hemolysis, and thrombogenicity. The 2014 American Heart Association/American College of Cardiology guidelines for the management of patients with valvular heart disease recommend an international normalized ratio (INR) of 2...
March 2017: Cardiology in Review
https://www.readbyqxmd.com/read/28168983/changes-in-operative-strategy-for-patients-enrolled-in-the-international-registry-of-acute-aortic-dissection-interventional-cohort-program
#10
Neil Parikh, Santi Trimarchi, Thomas G Gleason, Arnoud V Kamman, Marco di Eusanio, Truls Myrmel, Amit Korach, Hersh Maniar, Takeyoshi Ota, Ali Khoynezhad, Daniel G Montgomery, Nimesh D Desai, Kim A Eagle, Christoph A Nienaber, Eric M Isselbacher, Joseph Bavaria, Thoralf M Sundt, Himanshu J Patel
OBJECTIVE: Advancements in cardiothoracic surgery prompted investigation into changes in operative management for acute type A aortic dissections over time. METHODS: One thousand seven hundred thirty-two patients undergoing surgery for type A aortic dissection were identified from the International Registry of Acute Aortic Dissection Interventional Cohort Database. Patients were divided into time tertiles (T) (T1: 1996-2003, T2: 2004-2010, and T3: 2011-2016). RESULTS: Frequency of valve sparing procures increased (T1: 3...
January 9, 2017: Journal of Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28157747/cardioembolic-stroke
#11
Cumara B O'Carroll, Kevin M Barrett
PURPOSE OF REVIEW: Cardioembolic stroke is common and disproportionately more disabling than nonembolic mechanisms of stroke. Its incidence is expected to rise because of the age-related incidence of atrial fibrillation and an aging population. This article summarizes the different causes of cardioembolism and outlines current management guidelines. RECENT FINDINGS: Since cardioembolic stroke is not a single disease entity, its diagnosis requires initial clinical suspicion and a comprehensive evaluation, including ECG, echocardiography, brain imaging, and cardiac monitoring...
February 2017: Continuum: Lifelong Learning in Neurology
https://www.readbyqxmd.com/read/28157139/genetic-basis-of-aortic-valvular-disease
#12
Sara N Koenig, Joy Lincoln, Vidu Garg
PURPOSE OF REVIEW: Aortic valve disease is relatively common and encompasses both congenital and acquired forms. Bicuspid aortic valve (BAV) is the most common type of cardiac malformation and predisposes to the development of calcific aortic valve disease (CAVD). Since the description of the link between NOTCH1, BAV and CAVD approximately a decade ago, there have been significant advances in the genetic and molecular understanding of these diseases. RECENT FINDINGS: Recent work has defined the congenital cardiac phenotypes linked to mutations in NOTCH1, and in addition, novel etiologic genes for BAV have been discovered using new genetic technologies in humans...
February 2, 2017: Current Opinion in Cardiology
https://www.readbyqxmd.com/read/28149150/ventricular-tacyhcardia-in-a-patient-with-a-previous-history-of-endocarditis-and-ankylosan-spondylitis-a-challenging-case
#13
Yavuzer Koza, Muhammed Hakan Taş, Ziya Şimşek, Fuat Gündoğdu
Cardiac conduction defects are commonly observed in patients with ankylosing spondylitis, infective endocarditis, and aortic valve replacement. Each of these clinical situations can also present with ventricular tacyhcardia by different mechanisms. Here we report the case of a 53-year-old man with a medical history of untreated ankylosing spondylitis and aortic valve replacement who presented with ventricular tachycardia and underwent successful catheter ablation. Most ventricular tachycardia episodes were intermittent and drug resistant, which could have been caused by abnormal automaticity rather than re-entry...
October 2016: Eurasian Journal of Medicine
https://www.readbyqxmd.com/read/28139202/postoperative-analysis-of-the-mechanical-interaction-between-stent-and-host-tissue-in-patients-after-transcatheter-aortic-valve-implantation
#14
Raoul Hopf, Simon H Sündermann, Silvia Born, Carlos E Ruiz, Nicolas M Van Mieghem, Peter P de Jaegere, Francesco Maisano, Volkmar Falk, Edoardo Mazza
The analysis is based on a finite element procedure to extract the contact forces between an implanted Nitinol stent and the surrounding host tissue using postoperative CT images. The methodology was applied for patients (N=46) which have undergone a TAVI procedure with the Medtronic CoreValve Revalving System (MCRS) to obtain corresponding deformation and force maps. The postoperative CT data were recorded for each patient in both systolic and diastolic phase of the heart cycle. Scalar parameters were defined, which map deformed geometry and contact force field to mechanically relevant quantities: radial dilatation, radial shape distortion, non-convex points, mean force, a force deviation measure and a pressure equivalent...
December 30, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/28129319/mini-bentall-an-interesting-approach-for-selected-patients
#15
Elisa Mikus, Antonio Micari, Simone Calvi, Maria Salomone, Marco Panzavolta, Marco Paris, Mauro Del Giglio
OBJECTIVE: Minimally invasive surgery through an upper hemisternotomy for aortic valve replacement has become the routine approach with excellent results. Actually, the same minimally invasive access is used for complex ascending aorta procedures only in few centers. We report our experience with minimally invasive approach for aortic valve and ascending aorta replacement using Bentall technique. METHODS: From January 2010 to November 2015, a total of 238 patients received ascending aorta and aortic valve replacement using Bentall De Bono procedure at our institution...
January 2017: Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery
https://www.readbyqxmd.com/read/28121998/rheumatic-heart-disease-and-myxomatous-degeneration-differences-and-similarities-of-valve-damage-resulting-from-autoimmune-reactions-and-matrix-disorganization
#16
Carlo de Oliveira Martins, Lea Demarchi, Frederico Moraes Ferreira, Pablo Maria Alberto Pomerantzeff, Carlos Brandao, Roney Orismar Sampaio, Guilherme Sobreira Spina, Jorge Kalil, Edecio Cunha-Neto, Luiza Guilherme
Autoimmune inflammatory reactions leading to rheumatic fever (RF) and rheumatic heart disease (RHD) result from untreated Streptococcus pyogenes throat infections in individuals who exhibit genetic susceptibility. Immune effector mechanisms have been described that lead to heart tissue damage culminating in mitral and aortic valve dysfunctions. In myxomatous valve degeneration (MXD), the mitral valve is also damaged due to non-inflammatory mechanisms. Both diseases are characterized by structural valve disarray and a previous proteomic analysis of them has disclosed a distinct profile of matrix/structural proteins differentially expressed...
2017: PloS One
https://www.readbyqxmd.com/read/28119407/blood-flow-competition-after-aortic-valve-bypass-an-evaluation-using-computational-fluid-dynamics
#17
Koji Kawahito, Naoyuki Kimura, Kenji Komiya, Masanori Nakamura, Yoshio Misawa
OBJECTIVES: Aortic valve bypass (AVB) (apico-aortic conduit) remains an effective surgical alternative for patients in whom surgical aortic valve replacement or transcatheter aortic valve implantation is not feasible. However, specific complications include thrombus formation, possibly caused by stagnation arising from flow competition between the antegrade and retrograde flow, but this has not been fully investigated. The aim of this study was to analyse flow characteristics after AVB and to elucidate mechanisms of intra-aortic thrombus using computational fluid dynamics (CFD)...
January 24, 2017: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/28118792/noteworthy-articles-in-2016-for-the-cardiothoracic-anesthesiologist
#18
Dirk J Varelmann, J Daniel Muehlschlegel
Clinical research and outcome studies dominated the publication spectrum for the cardiothoracic anesthesiologist in 2016. Echocardiography is an important tool in the armamentarium of the cardiothoracic anesthesiologist. Technology is advancing at a fast pace: A new method to quantify the regurgitant volume in mitral regurgitation has been described in an experimental model and been validated in humans. Interesting studies on key elements of our daily practice have been published: Does tranexamic acid decrease the transfusion requirements after cardiac surgery? Are patients with a postoperative cognitive deficit at risk for dementia 7...
January 1, 2017: Seminars in Cardiothoracic and Vascular Anesthesia
https://www.readbyqxmd.com/read/28118265/intermittent-aortic-valve-opening-and-risk-of-thrombosis-in-vad-patients
#19
Claudius Mahr, Venkat Keshav Chivukula, Patrick McGah, Anthony R Prisco, Jennifer A Beckman, Nahush A Mokadam, Alberto Aliseda
This study evaluates quantitatively the impact that intermittent Aortic Valve opening has on the thrombogenicity in the aortic arch region for patients under Left Ventricular Assist Device therapy. The influence of flow through the Aortic Valve, opening once every five cardiac cycles, on the flow patterns in the ascending aortic is measured in a patient-derived CT-image-based model, after LVAD implantation. The mechanical environment of flowing platelets is investigated, by statistical treatment of outliers in Lagrangian particle tracking, and thrombogenesis metrics (platelet residence times and activation state characterized by shear stress accumulation) are compared for the cases of no Aortic Valve opening and intermittent Aortic Valve opening...
January 20, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28117617/patterns-and-determinants-of-functional-and-absolute-iron-deficiency-in-patients-undergoing-cardiac-rehabilitation-following-heart-surgery
#20
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
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