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Direct flow valve

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https://www.readbyqxmd.com/read/28321684/left-ventricular-flow-propagation-velocity-measurement-is-it-cast-in-stone
#1
Bee Ting Chan, Hak Koon Yeoh, Yih Miin Liew, Yang Faridah Abdul Aziz, Ganiga Srinivasaiah Sridhar, Christian Hamilton-Craig, David Platts, Einly Lim
This study aims to investigate the measurement of left ventricular flow propagation velocity, V p, using phase contrast magnetic resonance imaging and to assess the discrepancies resulting from inflow jet direction and individual left ventricular size. Three V p measuring techniques, namely non-adaptive (NA), adaptive positions (AP) and adaptive vectors (AV) method, were suggested and compared. We performed the comparison on nine healthy volunteers and nine post-infarct patients at four measurement positions, respectively, at one-third, one-half, two-thirds and the conventional 4 cm distances from the mitral valve leaflet into the left ventricle...
March 20, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28317480/novel-insights-into-complex-cardiovascular-pathologies-using-4d-flow-analysis-by-cardiovascular-magnetic-resonance-imaging
#2
Adam James Lewandowski, Betty Raman, Rajarshi Banerjee, Matteo Milanesi
BACKGROUND: It is essential that we are able to assess variations in blood flow in order to fully understand cardiovascular function in disease pathologies and for identification of individuals at long-term risk of cardiovascular disease development. Qualitative and quantitative assessments of blood flow by imaging modalities have been limited, and much of the accurate quantification has relied on invasive measures. METHODS: This review discusses how four-dimensional velocity cardiovascular magnetic resonance (4D flow CMR) offers increasing potential for the non-invasive assessment of blood flow in the heart and major blood vessels such as the aorta...
March 17, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28299822/when-to-use-femoral-vein-injection-for-diagnosis-of-patent-foramen-ovale-effect-of-a-persistent-eustachian-valve-on-right-atrial-flow-patterns-during-contrast-transesophageal-echocardiography
#3
Tat W Koh
Contrast echocardiography using agitated saline injected into the antecubital vein is the most common method used for the diagnosis of patent foramen ovale. We describe a case whereby the presence of a persistent eustachian valve and a "negative contrast sign" during contrast transesophageal echocardiography raised suspicion of a false-negative result. Femoral vein injection of contrast successfully demonstrated a patent foramen ovale. Femoral vein injection should be considered if this scenario is recognized because the eustachian valve directs blood preferentially from the inferior vena cava toward the interatrial septum and this route may prove to be more reliable...
March 16, 2017: Echocardiography
https://www.readbyqxmd.com/read/28292302/impact-of-left-ventricular-outflow-tract-ellipticity-on-the-grading-of-aortic-stenosis-in-patients-with-normal-ejection-fraction
#4
Frédéric Maes, Sophie Pierard, Christophe de Meester, Jamila Boulif, Mihaela Amzulescu, David Vancraeynest, Anne-Catherine Pouleur, Agnès Pasquet, Bernhard Gerber, Jean-Louis Vanoverschelde
BACKGROUND: The pathophysiology of paradoxical low-gradient (LG) severe aortic stenosis (SAS) remains controversial. As low transvalvular flow has been implicated, we sought to investigate the impact of left ventricular outflow tract (LVOT) ellipticity on the estimation of the LV stroke volume, the calculation of the aortic valve area (AVA) by use of the continuity equation and on AS severity grading. METHODS: We studied 190 consecutive patients (mean age: 72 ± 13 years; male: 57%) with SAS (indexed AVA < 0...
March 15, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28285747/effect-of-the-ventricular-folds-in-a-synthetic-larynx-model
#5
Stefan Kniesburges, Veronika Birk, Alexander Lodermeyer, Anne Schützenberger, Christopher Bohr, Stefan Becker
Within the human larynx, the ventricular folds serve primarily as a protecting valve during swallowing. They are located directly above the sound-generating vocal folds. During normal phonation, the ventricular folds are passive structures that are not excited to periodical oscillations. However, the impact of the ventricular folds on the phonation process has not yet been finally clarified. An experimental synthetic human larynx model was used to investigate the effect of the ventricular folds on the phonation process...
February 28, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28270219/quantification-of-aortic-stenosis-diagnostic-parameters-comparison-of-fast-3-direction-and-1-direction-phase-contrast-cmr-and-transthoracic-echocardiography
#6
Juliana Serafim da Silveira, Matthew Smyke, Adam V Rich, Yingmin Liu, Ning Jin, Debbie Scandling, Jennifer A Dickerson, Carlos E Rochitte, Subha V Raman, Lee C Potter, Rizwan Ahmad, Orlando P Simonetti
BACKGROUND: Aortic stenosis (AS) is a common valvular disorder, and disease severity is currently assessed by transthoracic echocardiography (TTE). However, TTE results can be inconsistent in some patients, thus other diagnostic modalities such as cardiovascular magnetic resonance (CMR) are demanded. While traditional unidirectional phase-contrast CMR (1Dir PC-CMR) underestimates velocity if the imaging plane is misaligned to the flow direction, multi-directional acquisitions are expected to improve velocity measurement accuracy...
March 7, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28254880/formation-and-function-of-intracardiac-valve-cells-in-the-drosophila-heart
#7
Kay Lammers, Bettina Abeln, Mirko Hüsken, Christine Lehmacher, Olympia Ekaterini Psathaki, Esther Alcorta, Heiko Meyer, Achim Paululat
Drosophila harbors a simple tubular heart that ensures hemolymph circulation within the body. The heart is built by a few different cell types, including cardiomyocytes that define the luminal heart channel and ostia cells that constitute openings in the heart wall allowing hemolymph to enter the heart chamber. Regulation of flow directionality within a tube, such as blood flow in arteries or insect hemolymph within the heart lumen, requires a dedicated gate, valve, or flap-like structure that prevents backflow of fluids...
March 2, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28230344/fully-automatic-in-syringe-magnetic-stirring-assisted-dispersive-liquid-liquid-microextraction-hyphenated-to-high-temperature-torch-integrated-sample-introduction-system-inductively-coupled-plasma-spectrometer-with-direct-injection-of-the-organic-phase
#8
Raquel Sánchez, Burkhard Horstkotte, Kateřina Fikarová, Hana Sklenářová, Salvador Maestre, Manuel Miró, Jose-Luis Todolí
A proof of concept study involving the online coupling of automatic dispersive liquid-liquid microextraction (DLLME) to inductively coupled plasma optical emission spectrometry (ICP OES) with direct introduction and analysis of the organic extract is herein reported for the first time. The flow-based analyzer features a lab-in-syringe (LIS) setup with an integrated stirring system, a Meinhard nebulizer in combination with a heated single-pass spray chamber, and a rotary injection valve, used as an online interface between the microextraction system and the detection instrument...
March 10, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28215797/in-situ-evaluation-of-water-and-energy-consumptions-at-the-end-use-level-the-influence-of-flow-reducers-and-temperature-in-baths
#9
C Matos, A Briga-Sá, I Bentes, D Faria, S Pereira
Nowadays, water and energy consumption is intensifying every year in most of the countries. This perpetual increase will not be supportable in the long run, making urgently to manage these resources on a sustainable way. Domestic consumptions of water and electric energy usually are related and it's important to study that relation, identifying opportunities for use efficient improvement. In fact, without an understanding of water-energy relations, there are water efficiency measures that may lead to unintentional costs in the energy efficiency field...
May 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28194824/left-intraventricular-pressure-gradients-improvement-after-aortic-valve-replacement-in-aortic-stenosis-patients
#10
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/28194732/late-post-avr-progression-of-bicuspid-aortopathy-link-to-hemodynamics
#11
Shiho Naito, Tatiana Gross, Kushtrim Disha, Yskert von Kodolitsch, Hermann Reichenspurner, Evaldas Girdauskas
BACKGROUND AND AIM OF THE STUDY: The ascending aortic dilatation may progress after aortic valve replacement (AVR) in bicuspid aortic valve (BAV) patients. Our aim was to evaluate rheological flow patterns and histological characteristics of the aneurysmal aorta in BAV patients at the time of reoperative aortic surgery. MATERIALS AND METHODS: 13 patients (mean age: 42 ± 9 years, 10 (77%) male) with significant progression of proximal aortopathy after isolated AVR surgery for BAV disease (i...
February 13, 2017: General Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28168785/intermediate-term-hemodynamic-effects-of-single-inferior-vena-cava-valve-implant-for-the-treatment-of-severe-tricuspid-regurgitation
#12
Val Rakita, Vladimir Lakhter, Pravin Patil, Brian P O'Neill
Severe tricuspid regurgitation (TR) remains a vastly undertreated disease, with sustained elevation of right atrial (RA) pressure directly resulting in chronic end-organ damage. Recently, bi-caval valve implantation has been shown to improve symptoms in patients with symptomatic TR who are at high risk for surgery. We present the first report of intermediate term hemodynamic effects of single inferior vena cava (IVC) valve implantation (CAVI) for treatment of severe TR. We performed CAVI on a 66-year-old female with severe TR, who suffered from repeat hospitalizations for treatment refractory NYHA class III-IV heart failure symptoms and had prohibitive operative risk...
February 7, 2017: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/28116867/pass-the-rock-calcium-the-achilles-heel-of-transcatheter-valve-replacement
#13
EDITORIAL
James M McCabe, Larry S Dean
Increasing annular calcification portends more adverse outcomes and worse hemodynamic results following percutaneous structural heart interventions. Though the Direct Flow prosthesis did not appear to have significantly different post-procedural gradients based on aortic valve calcium burden in a selected group of patients, the average residual gradients were relatively high in all cases and the presence of a paravalvular leak was more common with increasing valvular calcification. It is unclear how the Direct Flow prosthesis fits into the armamentarium of TAVR prostheses...
January 2017: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/28105745/thin-soft-skin-mounted-microfluidic-networks-with-capillary-bursting-valves-for-chrono-sampling-of-sweat
#14
Jungil Choi, Daeshik Kang, Seungyong Han, Sung Bong Kim, John A Rogers
Systems for time sequential capture of microliter volumes of sweat released from targeted regions of the skin offer the potential to enable analysis of temporal variations in electrolyte balance and biomarker concentration throughout a period of interest. Current methods that rely on absorbent pads taped to the skin do not offer the ease of use in sweat capture needed for quantitative tracking; emerging classes of electronic wearable sweat analysis systems do not directly manage sweat-induced fluid flows for sample isolation...
January 20, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28089455/comparison-of-transcatheter-aortic-valve-implantation-with-the-newest-generation-sapien-3-vs-direct-flow-medical-valve-in-a-single-center-cohort
#15
Eberhard Schulz, Alexander Jabs, Alexander Tamm, Patrick Herz, Andreas Schulz, Tommaso Gori, Stephan von Bardeleben, Walter Kasper-König, Ulrich Hink, Christian-Friedrich Vahl, Thomas Münzel
BACKGROUND: The latest generation transcatheter heart valves including Edwards Sapien 3 (ES3) and Direct Flow Medical (DFM) were designed to allow precise implantation at the intended position and to minimize prosthesis dysfunction as well as procedural complications. Our aim was to compare short-term functional and clinical outcomes of these 2 transcatheter aortic valve systems. METHODS: Of 174 patients undergoing transfemoral transcatheter aortic valve implantation (TAVI) at our institution between August 2013 and June 2015, 113 were treated with ES3 and 61 with DFM...
January 7, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28063094/stasis-dermatitis-pathophysiology-evaluation-and-management
#16
REVIEW
Swaminathan Sundaresan, Michael R Migden, Sirunya Silapunt
Stasis dermatitis commonly occurs in older age. It is caused by venous hypertension resulting from retrograde flow due to incompetent venous valves, valve destruction, or obstruction of the venous system. Further tissue changes arise from an inflammatory process mediated by metalloproteinases, which are up-regulated by ferric ion from extravasated red blood cells. Stasis dermatitis presents initially as poorly demarcated erythematous plaques of the lower legs bilaterally, classically involving the medial malleolus...
January 6, 2017: American Journal of Clinical Dermatology
https://www.readbyqxmd.com/read/28057868/glucocorticoid-receptor-alters-isovolumetric-contraction-and-restrains-cardiac-fibrosis
#17
Rachel V Richardson, Emma J Batchen, Adrian J W Thomson, Rowan Darroch, Xinlu Pan, Eva A Rog-Zielinska, Wiktoria Wyrzykowska, Kathleen Scullion, Emad A S Al-Dujaili, Mary E Diaz, Carmel M Moran, Christopher J Kenyon, Gillian A Gray, Karen E Chapman
Corticosteroids directly affect the heart and vasculature and are implicated in the pathogenesis of heart failure. Attention is focussed upon the role of the mineralocorticoid receptor (MR) in mediating pro-fibrotic and other adverse effects of corticosteroids upon the heart. In contrast, the role of the glucocorticoid receptor (GR) in the heart and vasculature is less well understood. We addressed this in mice with cardiomyocyte and vascular smooth muscle deletion of GR (SMGRKO mice). Survival of SMGRKO mice to weaning was reduced compared with that of littermate controls...
March 2017: Journal of Endocrinology
https://www.readbyqxmd.com/read/28043075/an-integrated-rotary-microfluidic-system-with-dna-extraction-loop-mediated-isothermal-amplification-and-lateral-flow-strip-based-detection-for-point-of-care-pathogen-diagnostics
#18
Byung Hyun Park, Seung Jun Oh, Jae Hwan Jung, Goro Choi, Ji Hyun Seo, Do Hyun Kim, Eun Yeol Lee, Tae Seok Seo
Point-of-care (POC) molecular diagnostics plays a pivotal role for the prevention and treatment of infectious diseases. In spite of recent advancement in microfluidic based POC devices, there are still rooms for development to realize rapid, automatic and cost-effective sample-to-result genetic analysis. In this study, we propose an integrated rotary microfluidic system that is capable of performing glass microbead based DNA extraction, loop mediated isothermal amplification (LAMP), and colorimetric lateral flow strip based detection in a sequential manner with an optimized microfluidic design and a rotational speed control...
May 15, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28038944/numerical-simulation-of-mitral-valve-prolapse-considering-the-effect-of-left-ventricle
#19
Seyedvahid Khodaei, Nasser Fatouraee, Malikeh Nabaei
Heart failure is one of the most important issues that has been investigated in recent research studies. Variations that occur in apparatus of mitral valve, such as chordae tendineaea rupture, can affect the valve function during ventricular contraction and lead to regurgitation from the left ventricle into the left atrium. One method for understanding mitral valve function in such conditions is computational analysis. In this paper, we develop a finite element model of mitral valve prolapse, considering the direct effect of left ventricular motion on blood flow interacting with the mitral valve...
December 28, 2016: Mathematical Biosciences
https://www.readbyqxmd.com/read/27992529/exposure-of-bacterial-biofilms-to-electrical-current-leads-to-cell-death-mediated-in-part-by-reactive-oxygen-species
#20
Cassandra L Brinkman, Suzannah M Schmidt-Malan, Melissa J Karau, Kerryl Greenwood-Quaintance, Daniel J Hassett, Jayawant N Mandrekar, Robin Patel
Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the 'electricidal effect', in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria...
2016: PloS One
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