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https://www.readbyqxmd.com/read/28921052/in-vitro-evaluation-of-flow-patterns-and-turbulent-kinetic-energy-in-trans-catheter-aortic-valve-prostheses
#1
Daniel Giese, Kilian Weiss, Bettina Baeßler, Navid Madershahian, Yeong-Hoon Choi, David Maintz, Alexander C Bunck
OBJECTIVES: The objective of the current work was to evaluate flow and turbulent kinetic energy in different transcatheter aortic valve implants using highly undersampled time-resolved multi-point 3-directional phase-contrast measurements (4D Flow MRI) in an in vitro setup. MATERIALS AND METHODS: A pulsatile flow setup was used with a compliant tubing mimicking a stiff left ventricular outflow tract and ascending aorta. Five different implants were measured using a highly undersampled multi-point 4D Flow MRI sequence...
September 18, 2017: Magma
https://www.readbyqxmd.com/read/28917773/redesigning-flow-injection-after-40-years-of-development-flow-programming
#2
Jaromir Jarda Ruzicka
Automation of reagent based assays, by means of Flow Injection (FI), is based on sample processing, in which a sample flows continuously towards and through a detector for quantification of the target analyte. The Achilles heel of this methodology, the legacy of Auto Analyzer®, is continuous reagent consumption, and continuous generation of chemical waste. However, flow programming, assisted by recent advances in precise pumping, combined with the lab-on-valve technique, allows the FI manifold to be designed around a single confluence point through which sample and reagents are sequentially directed by means of a series of flow reversals...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28900614/echocardiographic-evaluation-of-pulmonary-pressures-and-right-ventricular-function-after-pediatric-cardiac-surgery-a-simple-approach-for-the-intensivist
#3
REVIEW
Maurice Beghetti
Pulmonary hypertension (PH) is diagnosed using cardiac catheterization and is defined as an elevation of mean pulmonary artery pressure (PAP) greater than 25 mmHg. Although invasive hemodynamics remains the gold standard and is mandatory for disease confirmation, transthoracic echocardiography (TTE) is an extremely useful non-invasive and widely available tool that allows for screening and follow-up, in particular, in the acute setting. TTE may be a valuable alternative, allowing for direct measurement and/or indirect assessment of PAP...
2017: Frontiers in Pediatrics
https://www.readbyqxmd.com/read/28883786/arterial-pulsations-cannot-drive-intramural-periarterial-drainage-significance-for-a%C3%AE-drainage
#4
Alexandra K Diem, Matthew MacGregor Sharp, Maureen Gatherer, Neil W Bressloff, Roxana O Carare, Giles Richardson
Alzheimer's Disease (AD) is the most common form of dementia and to date there is no cure or efficient prophylaxis. The cognitive decline correlates with the accumulation of amyloid-β (Aβ) in the walls of capillaries and arteries. Our group has demonstrated that interstitial fluid and Aβ are eliminated from the brain along the basement membranes of capillaries and arteries, the intramural periarterial drainage (IPAD) pathway. With advancing age and arteriosclerosis, the stiffness of arterial walls, this pathway fails in its function and Aβ accumulates in the walls of arteries...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28860548/valley-filter-and-valve-effect-by-strong-electrostatic-potentials-in-graphene
#5
Juan Juan Wang, Su Liu, Jun Wang, Jun-Feng Liu
We report a theoretical study on the valley-filter and valley-valve effects in the monolayer graphene system by using electrostatic potentials, which are assumed to be electrically controllable. Based on a lattice model, we find that a single extremely strong electrostatic-potential barrier, with its strength exceeding the hopping energy of electrons, will significantly block one valley but allow the opposite valley flowing in the system, and this is dependent on the sign of the potential barrier as well as the flowing direction of electrons...
August 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28858090/prenatal-ultrasonic-diagnosis-of-absent-pulmonary-valve-syndrome-a-case-report
#6
Wen-Jun Zhang, Zhong-Lei Zhang, Jun-Jie Chang, Xiao-Yu Song
RATIONALE: Absent pulmonary valve syndrome (APVS) is a rare congenital heart disease that is often associated with tetralogy of Fallot (TOF). Here, we report 2 cases of APVS associated with TOF diagnosed via fetal echocardiography and discuss their specific ultrasonographic characteristics. PATIENT CONCERNS: Two pregnant women with suspicion of fetal heart anomaly were referred from their local hospitals to our hospital for fetal malformation screening and detailed fetal echocardiography...
September 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28852976/experimental-study-of-right-ventricular-hemodynamics-after-tricuspid-valve-replacement-therapies-to-treat-tricuspid-regurgitation
#7
Yen Ngoc Nguyen, Munirah Ismail, Foad Kabinejadian, Chi Wei Ong, Edgar Lik Wui Tay, Hwa Liang Leo
The increased understanding of right heart diseases has led to more aggressive interventions to manage functional tricuspid regurgitation (FTR). In some cases of FTR, prosthetic valve replacement is typically considered when concomitant organic components or significant geometrical distortions are involved in the pathology of the tricuspid valve. However, little is known of the performance of current devices in the right heart circulation. In this study, a novel in vitro mock circulatory system that incorporated a realistic tricuspid valve apparatus in a patient-specific silicon right ventricle (RV) was designed and fabricated...
August 29, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28838487/cardioscopically-guided-beating-heart-surgery-paravalvular-leak-repair
#8
Benoit Rosa, Zurab Machaidze, Margherita Mencattelli, Sunil Manjila, Borami Shin, Karl Price, Michael A Borger, Vinod Thourani, Pedro Del Nido, David W Brown, Christopher W Baird, John E Mayer, Pierre E Dupont
PURPOSE: There remains a paucity of direct visualization techniques for beating-heart intracardiac procedures. To address this need, we evaluated a novel cardioscope in the context of aortic paravalvular leaks (PVLs) localization and closure. DESCRIPTION: A porcine aortic PVL model was created using a custom-made bioprosthetic valve, and PVL presence was verified by epicardial echocardiography. Transapical delivery of occlusion devices guided solely by cardioscopy was attempted 13 times in a total of three pigs...
September 2017: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/28837613/impact-of-sheath-diameter-of-different-sheath-types-on-vascular-complications-and-mortality-in-transfemoral-tavi-approaches-using-the-proglide-closure-device
#9
Zisis Dimitriadis, Werner Scholtz, Stephan M Ensminger, Cornelia Piper, Thomas Bitter, Marcus Wiemer, Marios Vlachojannis, Jochen Börgermann, Lothar Faber, Dieter Horstkotte, Jan Gummert, Smita Scholtz
OBJECTIVE: Evaluation of the impact of the sheath diameter on vascular complications and mortality in transfemoral aortic valve implantation. METHOD: Between 2012 and 2014, 183 patients underwent the procedure using a sheath diameter of 18-24 F. This collective was divided into two groups: group 1, with a sheath diameter of 18F (G1, n = 94), consisted of patients with 18F Medtronic Sentrant and 18 F Direct Flow sheaths, and group 2 with a sheath diameter of 19-24 F (G2, n = 89) consisted of patients with Edwards expandable e-sheath and Solopath sheaths...
2017: PloS One
https://www.readbyqxmd.com/read/28831197/a-pulsed-air-model-of-blue-whale-b-call-vocalizations
#10
R P Dziak, J H Haxel, T-K Lau, S Heimlich, J Caplan-Auerbach, D K Mellinger, H Matsumoto, B Mate
Blue whale sound production has been thought to occur by Helmholtz resonance via air flowing from the lungs into the upper respiratory spaces. This implies that the frequency of blue whale vocalizations might be directly proportional to the size of their sound-producing organs. Here we present a sound production mechanism where the fundamental and overtone frequencies of blue whale B calls can be well modeled using a series of short-duration (<1 s) wavelets. We propose that the likely source of these wavelets are pneumatic pulses caused by opening and closing of respiratory valves during air recirculation between the lungs and laryngeal sac...
August 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28822982/evaluation-of-aortic-regurgitation-with-cardiac-magnetic-resonance-imaging-a-systematic-review
#11
REVIEW
James C Lee, Kelley R Branch, Christian Hamilton-Craig, Eric V Krieger
This review summaries the utility, application and data supporting use of cardiac magnetic resonance imaging (CMR) to evaluate and quantitate aortic regurgitation. We systematically searched Medline and PubMed for original research articles published since 2000 that provided data on the quantitation of aortic regurgitation by CMR and identified 11 articles for review. Direct aortic measurements using phase contrast allow quantitation of volumetric flow across the aortic valve and are highly reproducible and accurate compared with echocardiography...
August 19, 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/28818562/conduction-recovery-and-avoidance-of-permanent-pacing-after-transcatheter-aortic-valve-implantation
#12
Corinne Marzahn, Cornel Koban, Martin Seifert, Akihiro Isotani, Michael Neuß, Frank Hölschermann, Christian Butter
BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an established treatment option for patients with severe aortic stenosis and high surgical risk. Currently, various prosthesis types are available. Atrioventricular block (AVB) requiring pacemaker (PM) implantation is a typical complication after TAVI. This study investigated the recovery of AV node conduction and mid-term outcome of patients with or without PM implantation after TAVI according to prosthesis type. METHODS: From July 2008 to May 2015, 856 transcatheter heart valves were implanted at our center (age: 80...
August 14, 2017: Journal of Cardiology
https://www.readbyqxmd.com/read/28797433/periprocedural-myocardial-injury-depends-on%C3%A2-transcatheter-heart-valve-type-but-does%C3%A2-not%C3%A2-predict-mortality-in-patients-after-transcatheter-aortic-valve-replacement
#13
Anja Stundl, Regina Schulte, Hannah Lucht, Marcel Weber, Alexander Sedaghat, Jasmin Shamekhi, Berndt Zur, Eberhard Grube, Fritz Mellert, Armin Welz, Rolf Fimmers, Georg Nickenig, Nikos Werner, Jan-Malte Sinning
OBJECTIVES: The aims of this study were to determine plasma elevations of biomarkers of myocardial injury associated with transfemoral (TF) transcatheter aortic valve replacement (TAVR) and to evaluate their prognostic value. BACKGROUND: Increases in biomarkers of myocardial injury are a common finding after TAVR, but their clinical significance is unclear. METHODS: In 756 consecutive TF TAVR patients, cardiac high-sensitivity troponin I (hsTnI) and creatine kinase MB (CK-MB) levels were measured at pre-defined time points to assess the occurrence of myocardial injury (defined as 15 times the upper reference limit for hsTnI [≥1...
August 14, 2017: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/28793899/enumeration-of-circulating-endothelial-cell-frequency-as-a-diagnostic-marker-in-aortic-valve-surgery-a-flow-cytometric-approach
#14
Anton Sabashnikov, Klaus Neef, Vera Chesnokova, Leonie Wegener, Kathrin Godthardt, Maximilian Scherner, Elmar W Kuhn, Antje-Christin Deppe, Meike Lauer, Kaveh Eghbalzadeh, Mohamed Zeriouh, Parwis B Rahmanian, Jens Wippermann, Ferdinand Kuhn-Régnier, Navid Madershahian, Thorsten Wahlers, Alexander Weymann, Yeong-Hoon Choi
BACKGROUND: The frequency of circulating endothelial cells (CEC) in patients' peripheral blood can be assessed as a direct marker of endothelial damage. However, conventional enumeration methods are extremely challenging. We developed a novel, automated approach to determine CEC frequencies and tested this method on two groups of patients undergoing conventional (CAVR) versus trans-catheter aortic valve implantation (TAVI). METHODS: CEC frequencies were assessed by a flow cytometric approach, including automated pre-enrichment of CD34 positive blood cell subpopulation and isotype controls...
August 9, 2017: Journal of Cardiothoracic Surgery
https://www.readbyqxmd.com/read/28793046/erratum
#15
(no author information available yet)
[This corrects the article doi: 10.5935/abc.20170080].
July 2017: Arquivos Brasileiros de Cardiologia
https://www.readbyqxmd.com/read/28764326/comprehensive-study-of-the-flow-control-strategy-in-a-wirelessly-charged-centrifugal-microfluidic-platform-with-two-rotation-axes
#16
Yunzeng Zhu, Yiqi Chen, Xiangrui Meng, Jing Wang, Ying Lu, Youchun Xu, Jing Cheng
Centrifugal microfluidics has been widely applied in the sample-in-answer-out systems for the analyses of nucleic acids, proteins, and small molecules. However, the inherent characteristic of unidirectional fluid propulsion limits the flexibility of these fluidic chips. Providing an extra degree of freedom to allow the unconstrained and reversible pumping of liquid is an effective strategy to address this limitation. In this study, a wirelessly charged centrifugal microfluidic platform with two rotation axes has been constructed and the flow control strategy in such platform with two degrees of freedom was comprehensively studied for the first time...
September 5, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28741093/fetal-right-ventricular-prominence-associated-postnatal-abnormalities-and-coarctation-clinical-prediction-tool
#17
Alyssa Power, Alberto Nettel-Aguirre, Deborah Fruitman
Fetal right ventricular (RV) prominence is a known indicator of possible left-sided structural heart disease with a low positive predictive value for aortic coarctation. There is a paucity of data on identifying which fetuses with RV prominence will have postnatal arch obstruction. Our study objectives were to create a clinical prediction tool for coarctation and to describe the diagnostic outcomes of our cohort with fetal RV prominence. We performed a retrospective review of patients referred with fetal RV prominence from January 2009 to October 2015...
July 24, 2017: Pediatric Cardiology
https://www.readbyqxmd.com/read/28708210/particle-image-velocimetry-tests-on-pediatric-45-cc-and-30-cc-ventricle-assist-devices-effects-of-heart-rate-on-vad-operation
#18
Dariusz Witkowski, Damian Obidowski, Piotr Reorowicz, Daniel Jodko, Krzysztof Jozwik
BACKGROUND: This study investigated flow analysis inside pediatric ventricle assist devices (VADs) designed and manufactured at the Foundation for Cardiac Surgery Development (FRK), Zabrze, Poland. The main goal of the experiment was to define the minimal heart rate admissible in clinical practice. METHODS: The flow was directed by mechanical, single-disc valves developed at the Lodz University of Technology, Institute of Turbomachinery in Lodz, Poland. VAD operation conditions under different heart rates were analyzed...
July 8, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28694784/4d-flow-analysis-of-bav-related-fluid-dynamic-alterations-evidences-of-wall-shear-stress-alterations-in-absence-of-clinically-relevant-aortic-anatomical-remodeling
#19
Filippo Piatti, Francesco Sturla, Malenka M Bissell, Selene Pirola, Massimo Lombardi, Igor Nesteruk, Alessandro Della Corte, Alberto C L Redaelli, Emiliano Votta
Bicuspid aortic valve (BAV) is the most common congenital cardiac disease and is a foremost risk factor for aortopathies. Despite the genetic basis of BAV and of the associated aortopathies, BAV-related alterations in aortic fluid-dynamics, and particularly in wall shear stresses (WSSs), likely play a role in the progression of aortopathy, and may contribute to its pathogenesis. To test whether WSS may trigger aortopathy, in this study we used 4D Flow sequences of phase-contrast cardiac magnetic resonance imaging (CMR) to quantitatively compare the in vivo fluid dynamics in the thoracic aorta of two groups of subjects: (i) five prospectively enrolled young patients with normo-functional BAV and with no aortic dilation and (ii) ten age-matched healthy volunteers...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28681601/autonomous-control-of-fluids-in-a-wide-surface-tension-range-in-microfluidics
#20
Peng Ge, Shuli Wang, Yongshun Liu, Wendong Liu, Nianzuo Yu, Jianglei Zhang, Huaizhong Shen, Junhu Zhang, Bai Yang
In this paper, we report the preparation of anisotropic wetting surfaces that could control various wetting behaviors of liquids in a wide surface tension range (from water to oil), which could be employed as a platform for controlling the flow of liquids in microfluidics (MFs). The anisotropic wetting surfaces are chemistry-asymmetric "Janus" silicon cylinder arrays, which are fabricated via selecting and regulating the functional groups on the surface of each cylinder unit. Liquids (in a wide surface tension range) wet in a unidirectional manner along the direction that was modified by the group with large surface energy...
July 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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