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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/28717801/mimicking-arterial-thrombosis-in-a-3d-printed-microfluidic-in-vitro-vascular-model-based-on-computed-tomography-angiography-data
#1
Pedro F Costa, Hugo J Albers, John E A Linssen, Heleen H T Middelkamp, Linda van der Hout, Robert Passier, Albert van den Berg, Jos Malda, Andries D van der Meer
Arterial thrombosis is the main instigating factor of heart attacks and strokes, which result in over 14 million deaths worldwide every year. The mechanism of thrombosis involves factors from the blood and the vessel wall, and it also relies strongly on 3D vessel geometry and local blood flow patterns. Microfluidic chip-based vascular models allow controlled in vitro studies of the interaction between vessel wall and blood in thrombosis, but until now, they could not fully recapitulate the 3D geometry and blood flow patterns of real-life healthy or diseased arteries...
July 18, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28716304/three-dimensional-computational-model-of-a-blood-oxygenator-reconstructed-from-micro-ct-scans
#2
C D'Onofrio, R van Loon, S Rolland, R Johnston, L North, S Brown, R Phillips, J Sienz
Cardiopulmonary bypass procedures are one of the most common operations and blood oxygenators are the centre piece for the heart-lung machines. Blood oxygenators have been tested as entire devices but intricate details on the flow field inside the oxygenators remain unknown. In this study, a novel method is presented to analyse the flow field inside oxygenators based on micro Computed Tomography (μCT) scans. Two Hollow Fibre Membrane (HFM) oxygenator prototypes were scanned and three-dimensional full scale models that capture the device-specific fibre distributions are set up for computational fluid dynamics analysis...
July 14, 2017: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28673579/the-chloride-theory-a-unifying-hypothesis-for-renal-handling-and-body-fluid-distribution-in-heart-failure-pathophysiology
#3
Hajime Kataoka
Body fluid volume regulation is a complex process involving the interaction of various afferent (sensory) and neurohumoral efferent (effector) mechanisms. Historically, most studies focused on the body fluid dynamics in heart failure (HF) status through control of the balance of sodium, potassium, and water in the body, and maintaining arterial circulatory integrity is central to a unifying hypothesis of body fluid regulation in HF pathophysiology. The pathophysiologic background of the biochemical determinants of vascular volume in HF status, however, has not been known...
July 2017: Medical Hypotheses
https://www.readbyqxmd.com/read/28654638/increased-inspiratory-resistance-affects-the-dynamic-relationship-between-blood-pressure-changes-and-subarachnoid-space-width-oscillations
#4
Magdalena Wszedybyl-Winklewska, Jacek Wolf, Ewa Swierblewska, Katarzyna Kunicka, Kamila Mazur, Marcin Gruszecki, Pawel J Winklewski, Andrzej F Frydrychowski, Leszek Bieniaszewski, Krzysztof Narkiewicz
BACKGROUND AND OBJECTIVE: Respiration is known to affect cerebrospinal fluid (CSF) movement. We hypothesised that increased inspiratory resistance would affect the dynamic relationship between blood pressure (BP) changes and subarachnoid space width (SAS) oscillations. METHODS: Experiments were performed in a group of 20 healthy volunteers undergoing controlled intermittent Mueller Manoeuvres (the key characteristic of the procedure is that a studied person is subjected to a controlled, increased inspiratory resistance which results in marked potentiation of the intrathoracic negative pressure)...
2017: PloS One
https://www.readbyqxmd.com/read/28631361/optimal-right-heart-filling-pressure-in-acute-respiratory-distress-syndrome-determined-by-strain-echocardiography
#5
Romel Garcia-Montilla, Faryal Imam, Mi Miao, Kathryn Stinson, Akram Khan, Stephen Heitner
INTRODUCTION: Right ventricular (RV) systolic dysfunction is common in acute respiratory distress syndrome (ARDS). While preload optimization is crucial in its management, dynamic fluid responsiveness indices lack reliability, and there is no consensus on target central venous pressure (CVP). We analyzed the utility of RV free wall longitudinal strain (RVFWS) in the estimation of optimal RV filling pressure in ARDS. METHODS: A retrospective cross-sectional analysis of clinical data and echocardiograms of patients with ARDS was performed...
June 2017: Echocardiography
https://www.readbyqxmd.com/read/28608962/image-based-computational-fluid-dynamics-in-the-lung-virtual-reality-or-new-clinical-practice
#6
REVIEW
Kelly S Burrowes, Jan De Backer, Haribalan Kumar
The development and implementation of personalized medicine is paramount to improving the efficiency and efficacy of patient care. In the respiratory system, function is largely dictated by the choreographed movement of air and blood to the gas exchange surface. The passage of air begins in the upper airways, either via the mouth or nose, and terminates at the alveolar interface, while blood flows from the heart to the alveoli and back again. Computational fluid dynamics (CFD) is a well-established tool for predicting fluid flows and pressure distributions within complex systems...
June 13, 2017: Wiley Interdisciplinary Reviews. Systems Biology and Medicine
https://www.readbyqxmd.com/read/28587389/comparison-of-the-hemodynamics-and-dynamics-of-fluid-shift-of-ringer-s-solution-before-surgery-in-children-and-adults
#7
Guizhou Zhu, Yuhong Li, Guomei Ru, Qiannan Ding
The present study investigated the hemodynamics, vascular and extravascular volume expansion induced by infusion of lactated Ringer's solution in children and adults before surgery. This was a prospective randomized double-blind study. A total of 28 patients (14 children and 14 adult patients; American Society of Anesthesiology status I) scheduled for similar minor pelvic, anal rectal or lower limb surgery were recruited for the present study. All patients were administered with 10 ml/kg of lactated Ringer's solution at a constant rate over 20 min...
June 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28586917/toward-the-virtual-benchmarking-of-pneumatic-ventricular-assist-devices-application-of-a-novel-fluid-structure-interaction-based-strategy-to-the-penn-state-12-cc-device
#8
Alessandro Caimi, Francesco Sturla, Bryan Good, Marco Vidotto, Rachele De Ponti, Filippo Piatti, Keefe B Manning, Alberto Redaelli
The pediatric use of pneumatic ventricular assist devices (VADs) as a bridge to heart transplant still suffers for short-term major complications such as bleeding and thromboembolism. Although numerical techniques are increasingly exploited to support the process of device optimization, an effective virtual benchmark is still lacking. Focusing on the 12 cc Penn State pneumatic VAD, we developed a novel fluid-structure interaction (FSI) model able to capture the device functioning, reproducing the mechanical interplay between the diaphragm, the blood chamber, and the pneumatic actuation...
August 1, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28575332/effects-of-arterial-load-variations-on-dynamic-arterial-elastance-an-experimental-study
#9
M I Monge García, P Guijo González, M Gracia Romero, A Gil Cano, A Rhodes, R M Grounds, M Cecconi
Background.: Dynamic arterial elastance (Ea dyn ), the relationship between pulse pressure variation (PPV) and stroke volume variation (SVV), has been suggested as a functional assessment of arterial load. The aim of this study was to evaluate the impact of arterial load changes during acute pharmacological changes, fluid administration, and haemorrhage on Ea dyn . Methods.: Eighteen anaesthetized, mechanically ventilated New Zealand rabbits were studied. Arterial load changes were induced by phenylephrine ( n =9) or nitroprusside ( n =9)...
June 1, 2017: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/28567658/left-ventricular-assist-devices-challenges-toward-sustaining-long-term-patient-care
#10
REVIEW
Marianne Schmid Daners, Friedrich Kaufmann, Raffael Amacher, Gregor Ochsner, Markus J Wilhelm, Aldo Ferrari, Edoardo Mazza, Dimos Poulikakos, Mirko Meboldt, Volkmar Falk
Over the last few decades, the left ventricular assist device (LVAD) technology has been tremendously improved transitioning from large and noisy paracorporeal volume displacement pumps to small implantable turbodynamic devices with only a single transcutaneous element, the driveline. Nevertheless, there remains a great demand for further improvements to meet the challenge of having a robust and safe device for long-term therapy. Here, we review the state of the art and highlight four key areas of needed improvement targeting long-term, sustainable LVAD function: (1) LVADs available today still have a high risk of thromboembolic and bleeding events that could be addressed by the rational fabrication of novel surface structures and endothelialization approaches aiming at improving the device hemocompatibility...
May 31, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28548989/imaging-adult-patients-with-fontan-circulation
#11
Salil Ginde, Benjamin H Goot, Peter C Frommelt
PURPOSE OF REVIEW: Survival after the Fontan procedure for palliation of single ventricle congenital heart disease has improved. However, adults with Fontan circulation are at risk for several complications including heart failure, thromboembolism, and protein-losing enteropathy. This review discusses the role of noninvasive imaging for surveillance and early detection of anatomic and functional abnormalities of the Fontan circulation that can impact the risk for Fontan failure over time...
May 25, 2017: Current Opinion in Cardiology
https://www.readbyqxmd.com/read/28525548/computational-fluid-dynamics-characterization-of-pulsatile-flow-in-central-and-sano-shunts-connected-to-the-pulmonary-arteries-importance-of-graft-angulation-on-shear-stress-induced-platelet-mediated-thrombosis
#12
Robert Ascuitto, Nancy Ross-Ascuitto, Martin Guillot, Carey Celestin
OBJECTIVES: Central (aorta) and Sano (right ventricle)-to-pulmonary artery (PA) shunts, palliative operations for infants with complex heart defects, can develop life-threatening thrombosis. We employed computational fluid dynamics (CFD) to study pulsatile flow in these shunts, with the goal to identify haemodynamic characteristics conducive to thrombus formation. METHODS: CFD, using the finite volume method with cardiac catheterization data, and computer simulations, based on angiography, were employed to determine flow-velocity field, wall shear stress (WSS) profile and oscillatory shear index (OSI)...
May 19, 2017: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/28507239/pulsatile-flow-in-ventricular-catheters-for-hydrocephalus
#13
Á Giménez, M Galarza, U Thomale, M U Schuhmann, J Valero, J M Amigó
The obstruction of ventricular catheters (VCs) is a major problem in the standard treatment of hydrocephalus, the flow pattern of the cerebrospinal fluid (CSF) being one important factor thereof. As a first approach to this problem, some of the authors studied previously the CSF flow through VCs under time-independent boundary conditions by means of computational fluid dynamics in three-dimensional models. This allowed us to derive a few basic principles which led to designs with improved flow patterns regarding the obstruction problem...
June 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28482384/-effects-and-mechanisms-of-high-volume-hemofiltration-on-endotoxin-induced-acute-lung-injury-of-piglets
#14
W M Chen, G F Yan, Z J Lu, G P Lu
Objective: To compare the effects of high-volume hemofiltration (HVHF) and continuous veno-venous hemofiltration (CVVH) on cardiopulmonary functions, lung fluid balance, lung damage and cytokine expression in endotoxin-induced acute lung injury piglet model, and to further evaluate the value of high-volume hemofiltration in acute lung injury. Method: Eighteen piglets were randomly divided into the control group (6 piglets), the CVVH group (6 piglets) and the HVHF group (6 piglets). By general anesthesia, the intravenous infusion of 0...
May 4, 2017: Zhonghua Er Ke za Zhi. Chinese Journal of Pediatrics
https://www.readbyqxmd.com/read/28475237/production-of-zebrafish-cardiospheres-and-cardiac-progenitor-cells-in-vitro-and-three-dimensional-culture-of-adult-zebrafish-cardiac-tissue-in-scaffolds
#15
Wendy R Zeng, Siew-Joo Beh, Robert J Bryson-Richardson, Pauline M Doran
The hearts of adult zebrafish (Danio rerio) are capable of complete regeneration in vivo even after major injury, making this species of particular interest for understanding the growth and differentiation processes required for cardiac tissue engineering. To date, little research has been carried out on in vitro culture of adult zebrafish cardiac cells. In this work, progenitor-rich cardiospheres suitable for cardiomyocyte differentiation and myocardial regeneration were produced from adult zebrafish hearts...
May 5, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28454910/evaluation-of-an-aortic-valve-prosthesis-fluid-structure-interaction-or-structural-simulation
#16
Giulia Luraghi, Wei Wu, Francesco De Gaetano, Josè Felix Rodriguez Matas, Geoff D Moggridge, Marta Serrani, Joanna Stasiak, Maria Laura Costantino, Francesco Migliavacca
Bio-inspired polymeric heart valves (PHVs) are excellent candidates to mimic the structural and the fluid dynamic features of the native valve. PHVs can be implanted as prosthetic alternative to currently clinically used mechanical and biological valves or as potential candidate for a minimally invasive treatment, like the transcatheter aortic valve implantation. Nevertheless, PHVs are not currently used for clinical applications due to their lack of reliability. In order to investigate the main features of this new class of prostheses, pulsatile tests in an in-house pulse duplicator were carried out and reproduced in silico with both structural Finite-Element (FE) and Fluid-Structure interaction (FSI) analyses...
June 14, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28444075/applicability-of-respiratory-variations-in-stroke-volume-and-its-surrogates-for-dynamic-fluid-responsiveness-prediction-in-critically-ill-patients-a-systematic-review-of-the-prevalence-of-required-conditions
#17
Leandro Utino Taniguchi, Fernando Godinho Zampieri, Antonio Paulo Nassar
Objective: The present systematic review searched for published data on the prevalence of required conditions for proper assessment in critically ill patients. Methods: The Medline, Scopus and Web of Science databases were searched to identify studies that evaluated the prevalence of validated conditions for the fluid responsiveness assessment using respiratory variations in the stroke volume or another surrogate in adult critically ill patients. The primary outcome was the suitability of the fluid responsiveness evaluation...
January 2017: Revista Brasileira de Terapia Intensiva
https://www.readbyqxmd.com/read/28424884/principle-and-basic-property-of-the-sequential-flow-pump
#18
Shintaro Hara, Erina Maeno, Xinyang Li, Terumi Yurimoto, Takashi Isoyama, Itsuro Saito, Toshiya Ono, Yusuke Abe
In the emergency care field, early treatment of acute heart or respiratory failure has been a global concern. In severe cases, patients are frequently required to be on an extracorporeal membrane oxygenator (ECMO) life support. To make the ECMO system more compact and portable, we proposed a sequential flow-type centrifugal pump named the sequential flow pump (SFP). In this study, principle and basic properties of this novel blood pump were examined by computational fluid dynamic (CFD) analysis and an experimental model...
April 19, 2017: Journal of Artificial Organs: the Official Journal of the Japanese Society for Artificial Organs
https://www.readbyqxmd.com/read/28417585/speckle-variance-optical-coherence-tomography-of-blood-flow-in-the-beating-mouse-embryonic-heart
#19
Olga A Grishina, Shang Wang, Irina V Larina
Efficient separation of blood and cardiac wall in the beating embryonic heart is essential and critical for experiment-based computational modelling and analysis of early-stage cardiac biomechanics. Although speckle variance optical coherence tomography (SV-OCT) relying on calculation of intensity variance over consecutively acquired frames is a powerful approach for segmentation of fluid flow from static tissue, application of this method in the beating embryonic heart remains challenging because moving structures generate SV signal indistinguishable from the blood...
May 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28364199/flow-dynamics-and-energy-efficiency-of-flow-in-the-left-ventricle-during-myocardial-infarction
#20
Vivek Vasudevan, Adriel Jia Jun Low, Sarayu Parimal Annamalai, Smita Sampath, Kian Keong Poh, Teresa Totman, Muhammad Mazlan, Grace Croft, A Mark Richards, Dominique P V de Kleijn, Chih-Liang Chin, Choon Hwai Yap
Cardiovascular disease is a leading cause of death worldwide, where myocardial infarction (MI) is a major category. After infarction, the heart has difficulty providing sufficient energy for circulation, and thus, understanding the heart's energy efficiency is important. We induced MI in a porcine animal model via circumflex ligation and acquired multiple-slice cine magnetic resonance (MR) images in a longitudinal manner-before infarction, and 1 week (acute) and 4 weeks (chronic) after infarction. Computational fluid dynamic simulations were performed based on MR images to obtain detailed fluid dynamics and energy dynamics of the left ventricles...
March 31, 2017: Biomechanics and Modeling in Mechanobiology
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