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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/28820467/aquaporin-4-functionality-and-virchow-robin-space-water-dynamics-physiological-model-for-neurovascular-coupling-and-glymphatic-flow
#1
REVIEW
Tsutomu Nakada, Ingrid L Kwee, Hironaka Igarashi, Yuji Suzuki
The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries...
August 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28812203/assessment-of-methodologies-to-calculate-intraventricular-pressure-differences-in-computational-models-and-patients
#2
Francisco J Londono-Hoyos, Abigail Swillens, Joris Van Cauwenberge, Brett Meyers, Maheswara Reddy Koppula, Pavlos Vlachos, Julio A Chirinos, Patrick Segers
Intraventricular pressure differences (IVPDs) govern left ventricular (LV) efficient filling and are a significant determinant of LV diastolic function. Our primary aim is to assess the performance of available methods (color M-mode (CMM) and 1D/2D MRI-based methods) to determine IVPDs from intracardiac flow measurements. Performance of three methods to calculate IVPDs was first investigated via an LV computational fluid dynamics (CFD) model. CFD velocity data were derived along a modifiable scan line, mimicking ultrasound/MRI acquisition of 1D (IVPDCMM/IVPD1D MRI) and 2D (IVPD2D MRI) velocity-based IVPD information...
August 16, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28800300/intraventricular-vector-flow-mapping-a-doppler-based-regularized-problem-with-automatic-model-selection
#3
Kondo Claude Assi, Etienne Gay, Christophe Chnafa, Simon Mendez, Franck Nicoud, Juan F P J Abascal, Pierre Lantelme, François Tournoux, Damien Garcia
We propose a regularized least-squares method for reconstructing 2D velocity vector fields within the left ventricular cavity from single-view color Doppler echocardiographic images. Vector flow mapping is formulated as a quadratic optimization problem based on an [Formula: see text]-norm minimization of a cost function composed of a Doppler data-fidelity term and a regularizer. The latter contains three physically interpretable expressions related to 2D mass conservation, Dirichlet boundary conditions, and smoothness...
August 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28795671/-two-dimensional-speckle-tracking-imaging-in-assessing-the-left-ventricular-systolic-function-and-its-dynamic-changes-of-patients-with-septic-shock
#4
Fei Yang, Yong Chen, Ruiqiang Zheng, Yong Ma, Haidi Yu, Wenjuan Zhang, Yang Zhang
OBJECTIVE: To evaluate early and dynamic changes of the left ventricular systolic function of patients with septic shock by two-dimensional speckle tracking imaging (2D-STI), and to provide guidance for treatment and prognosis. METHODS: Fifty-eight septic shock patients admitted to intensive care unit (ICU) of Subei People's Hospital from January 2016 to April 2017 were enrolled. The septic shock patients were given early fluid resuscitation. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), early diastolic mitral flow velocity/early diastolic mitral annular peak velocity (E/Em) were obtained by conventional echocardiography, and the left ventricular global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) were obtained by 2D-STI before fluid resuscitation and 1, 3, 7, 14 days after fluid resuscitation...
August 2017: Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
https://www.readbyqxmd.com/read/28782911/simulation-of-aortopulmonary-collateral-flow-in-fontan-patients-for-use-in-prediction-of-interventional-outcomes
#5
Petter Frieberg, Pia Sjöberg, Johan Revstedt, Einar Heiberg, Petru Liuba, Marcus Carlsson
PURPOSE: Patients with complex congenital heart disease may need to be converted to a Fontan circulation with systemic venous return surgically connected to the pulmonary circulation. These patients frequently form aortopulmonary collaterals (APC), that is arterial inflows to the pulmonary artery vascular tree. The aim of this study was to develop a method to calculate the effect of APC on the pulmonary flow distribution based on magnetic resonance imaging (MRI) measurements and computational fluid dynamics simulations in order to enable prediction of interventional outcomes in Fontan patients...
August 7, 2017: Clinical Physiology and Functional Imaging
https://www.readbyqxmd.com/read/28777391/design-and-numerical-evaluation-of-an-axial-partial-assist-blood-pump-for-chinese-and-other-heart-failure-patients
#6
Guang-Mao Liu, Dong-Hai Jin, Jian-Ye Zhou, Xi-Hang Jiang, Han-Song Sun, Yan Zhang, Hai-Bo Chen, Sheng-Shou Hu, Xing-Min Gui
A fully implantable axial left ventricular assist device LAP31 was developed for Chinese or other heart failure patients who need partial support. Based on the 5-Lpm total cardiac blood output of Chinese without heart failure disease, the design point of LAP31 was set to a flow rate of 3 Lpm with 100-mmHg pressure head. To achieve the required pressure head and good hemolytic performance, a structure that includes a spindly rotor hub and a diffuser with splitter and cantilevered main blades was developed. Computational fluid dynamics (CFD) was used to analyze the hydraulic and hemodynamic performance of LAP31...
August 2, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28751011/a-coupled-mitral-valve-left-ventricle-model-with-fluid-structure-interaction
#7
Hao Gao, Liuyang Feng, Nan Qi, Colin Berry, Boyce E Griffith, Xiaoyu Luo
Understanding the interaction between the valves and walls of the heart is important in assessing and subsequently treating heart dysfunction. This study presents an integrated model of the mitral valve (MV) coupled to the left ventricle (LV), with the geometry derived from in vivo clinical magnetic resonance images. Numerical simulations using this coupled MV-LV model are developed using an immersed boundary/finite element method. The model incorporates detailed valvular features, left ventricular contraction, nonlinear soft tissue mechanics, and fluid-mediated interactions between the MV and LV wall...
July 24, 2017: Medical Engineering & Physics
https://www.readbyqxmd.com/read/28744907/design-and-hemocompatibility-analysis-of-a-double-suction-injection-suspension-blood-pump-using-computational-fluid-dynamics-methods
#8
Yue Wu, Liangfan Zhu, Yun Luo
The blood pump has become a possible solution to heart diseases. For the prevention of device failure and hemocompatibility problems, a rotary pump with suspended bearing is a preferred solution. In our previous work, a novel injection suspension method has been introduced to levitate the rotor. The suspension method is totally passive. This study aims to apply this suspension method to a double-suction pump, and the property of the pump was investigated using computational fluid dynamics (CFD) methods. The flow field of the pump is simulated based on the SST k-ω turbulent model...
July 26, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28744840/organ-dynamics-and-fluid-dynamics-of-the-hh25-chick-embryonic-cardiac-ventricle-as-revealed-by-a-novel-4d-high-frequency-ultrasound-imaging-technique-and-computational-flow-simulations
#9
Sheldon Ho, Germaine Xin Yi Tan, Toon Jin Foo, Nhan Phan-Thien, Choon Hwai Yap
Past literature has provided evidence that a normal mechanical force environment of blood flow may guide normal development while an abnormal environment can lead to congenital malformations, thus warranting further studies on embryonic cardiovascular flow dynamics. In the current study, we developed a non-invasive 4D high-frequency ultrasound technique, and use it to analyze cardiovascular organ dynamics and flow dynamics. Three chick embryos at stage HH25 were scanned with high frequency ultrasound in cine-B-mode at multiple planes spaced at 0...
July 25, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28744828/review-of-numerical-methods-for-simulation-of-mechanical-heart-valves-and-the-potential-for-blood-clotting
#10
Mohamad Shukri Zakaria, Farzad Ismail, Masaaki Tamagawa, Ahmad Fazli Abdul Aziz, Surjatin Wiriadidjaja, Adi Azrif Basri, Kamarul Arifin Ahmad
Even though the mechanical heart valve (MHV) has been used routinely in clinical practice for over 60 years, the occurrence of serious complications such as blood clotting remains to be elucidated. This paper reviews the progress that has been made over the years in terms of numerical simulation method and the contribution of abnormal flow toward blood clotting from MHVs in the aortic position. It is believed that this review would likely be of interest to some readers in various disciplines, such as engineers, scientists, mathematicians and surgeons, to understand the phenomenon of blood clotting in MHVs through computational fluid dynamics...
July 26, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28733923/cardiovascular-mechanics-in-the-early-stages-of-pulmonary-hypertension-a-computational-study
#11
Sebastián Acosta, Charles Puelz, Béatrice Rivière, Daniel J Penny, Ken M Brady, Craig G Rusin
We formulate and study a new mathematical model of pulmonary hypertension. Based on principles of fluid and elastic dynamics, we introduce a model that quantifies the stiffening of pulmonary vasculature (arteries and arterioles) to reproduce the hemodynamics of the pulmonary system, including physiologically consistent dependence between compliance and resistance. This pulmonary model is embedded in a closed-loop network of the major vessels in the body, approximated as one-dimensional elastic tubes, and zero-dimensional models for the heart and other organs...
July 21, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28721492/peristaltic-like-motion-of-the-human-fetal-right-ventricle-and-its-effects-on-fluid-dynamics-and-energy-dynamics
#12
Hadi Wiputra, Guat Ling Lim, Khong Chun Chua, R Nivetha, Sanah Merchant Soomar, Arijit Biwas, Citra Nurfarah Zaini Mattar, Hwa Liang Leo, Choon Hwai Yap
In both adult human and canine, the cardiac right ventricle (RV) is known to exhibit a peristaltic-like motion, where RV sinus (inflow region) contracts first and the infundibulum (outflow region) later, in a wave-like contraction motion. The delay in contraction between the sinus and infundibulum averaged at 15% of the cardiac cycle and was estimated to produce an intra-ventricular pressure difference of 15 mmHg. However, whether such a contractile motion occurs in human fetuses as well, its effects on hemodynamics remains unknown, and are the subject of the current study...
July 18, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28717801/mimicking-arterial-thrombosis-in-a-3d-printed-microfluidic-in-vitro-vascular-model-based-on-computed-tomography-angiography-data
#13
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...
August 8, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28716304/three-dimensional-computational-model-of-a-blood-oxygenator-reconstructed-from-micro-ct-scans
#14
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...
September 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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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