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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/28327144/computational-medical-imaging-and-hemodynamics-framework-for-functional-analysis-and-assessment-of-cardiovascular-structures
#1
REVIEW
Kelvin K L Wong, Defeng Wang, Jacky K L Ko, Jagannath Mazumdar, Thu-Thao Le, Dhanjoo Ghista
Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential...
March 21, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28324943/overcoming-spatio-temporal-limitations-using-dynamically-scaled-in-vitro-pc-mri-a-flow-field-comparison-to-true-scale-computer-simulations-of-idealized-stented-and-patient-specific-left-main-bifurcations
#2
Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan
The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28276071/cfd-and-bernoulli-based-pressure-drop-estimates-a-comparison-using-patient-anatomies-from-heart-and-aortic-valve-segmentation-of-ct-images
#3
Jürgen Weese, Angela Lungu, Jochen Peters, Frank M Weber, Irina Waechter-Stehle, D Rodney Hose
PURPOSE: An aortic valve stenosis is an abnormal narrowing of the aortic valve (AV). It impedes blood flow and is often quantified by the geometric orifice area of the AV (AVA) and the pressure drop (PD). Using the Bernoulli equation, a relation between the PD and the effective orifice area (EOA) represented by the area of the vena contracta (VC) downstream of the AV can be derived. We investigate the relation between the AVA and the EOA using patient anatomies derived from cardiac computed tomography (CT) angiography images and computational fluid dynamic (CFD) simulations...
March 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/28249360/heart-function-and-hemodynamics-analysis-for-zebrafish-embryos
#4
REVIEW
Huseyin C Yalcin, Armin Amindari, Jonathan T Butcher, Asma Althani, Magdi Yacoub
The zebrafish has emerged to become a powerful vertebrate animal model for cardiovascular research in recent years. Its advantages include easy genetic manipulation, transparency, small size, low cost, and the ability to survive without active circulation at early stages of development. Sequencing the whole genome and identifying orthologue genes with human genome enabled to induce clinically relevant cardiovascular defects via genetic approaches. Heart function and disturbed hemodynamics need to be assessed in a reliable manner for these disease models in order to reveal mechanobiology of induced defects...
March 1, 2017: Developmental Dynamics: An Official Publication of the American Association of Anatomists
https://www.readbyqxmd.com/read/28242061/patient-specific-in-vitro-models-for-hemodynamic-analysis-of-congenital-heart-disease-additive-manufacturing-approach
#5
Rafael Medero, Sylvana García-Rodríguez, Christopher J François, Alejandro Roldán-Alzate
Non-invasive hemodynamic assessment of total cavopulmonary connection (TCPC) is challenging due to the complex anatomy. Additive manufacturing (AM) is a suitable alternative for creating patient-specific in vitro models for flow measurements using four-dimensional (4D) Flow MRI. These in vitro systems have the potential to serve as validation for computational fluid dynamics (CFD), simulating different physiological conditions. This study investigated three different AM technologies, stereolithography (SLA), selective laser sintering (SLS) and fused deposition modeling (FDM), to determine differences in hemodynamics when measuring flow using 4D Flow MRI...
February 7, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28226721/overcoming-spatio-temporal-limitations-using-dynamically-scaled-in-vitro-pc-mri-a-flow-field-comparison-to-true-scale-computer-simulations-of-idealized-stented-and-patient-specific-left-main-bifurcations
#6
Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan, Susann Beier, John Ormiston, Mark Webster, John Cater, Stuart Norris, Pau Medrano-Gracia, Alistair Young, Kathleen Gilbert, Brett Cowan, Stuart Norris, Brett Cowan, Pau Medrano-Gracia, Kathleen Gilbert, Mark Webster, Alistair Young, Susann Beier, John Cater, John Ormiston
The majority of patients with angina or heart failure have coronary artery disease. Left main bifurcations are particularly susceptible to pathological narrowing. Flow is a major factor of atheroma development, but limitations in imaging technology such as spatio-temporal resolution, signal-to-noise ratio (SNRv), and imaging artefacts prevent in vivo investigations. Computational fluid dynamics (CFD) modelling is a common numerical approach to study flow, but it requires a cautious and rigorous application for meaningful results...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225865/continuous-blood-purification-treatment-for-endotoxin-induced-acute-respiratory-distress-syndrome
#7
Y Jiang, R Lin, Y Xu, S Zhang, K Cui, M Zhu, A Li, C Chen, J Yang, W Yang
This study aimed to explore the effects of continuous blood purification (CBP) treatment in pigs affected with acute respiratory distress syndrome (ARDS). A total of 12 healthy male pigs, weighing 12±1.8 kg, were randomly and equally assigned to the control and experimental groups. The ARDS pig model was prepared by intravenous injections of endotoxin (20 µg/kg). The control group was given conventional supportive therapy, while the experimental group was given continuous veno-venous hemofiltration therapy...
February 16, 2017: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
https://www.readbyqxmd.com/read/28210935/the-effect-of-fluid-resuscitation-on-the-effective-circulating-volume-in-patients-undergoing-liver-surgery-a-post-hoc-analysis-of-a-randomized-controlled-trial
#8
Jaap Jan Vos, A F Kalmar, H G D Hendriks, J Bakker, T W L Scheeren
To assess the significance of an analogue of the mean systemic filling pressure (Pmsa) and its derived variables, in providing a physiology based discrimination between responders and non-responders to fluid resuscitation during liver surgery. A post-hoc analysis of data from 30 patients undergoing major hepatic surgery was performed. Patients received 15 ml kg(-1) fluid in 30 min. Fluid responsiveness (FR) was defined as an increase of 20% or greater in cardiac index, measured by FloTrac-Vigileo(®). Dynamic preload variables (pulse pressure variation and stroke volume variation: PPV, SVV) were recorded additionally...
February 16, 2017: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/28181776/cardiovascular-adjustments-to-heat-stress-during-prolonged-exercise
#9
Luna Rizzo, Martin W Thompson
Prolonged effort in hot environments is increasing popular in extreme sports. The number of long distance athletes taking part in races in extremely warm condition, as in deserts, is larger than in the past and also the race distances are increased thus. The demanding for the heart function are higher than those challenged in the past only by few athletes and in easier conditions. This puts news challenges on the professional involved in these activities and there is a need to better understand how the cardiocirculatory system responses in these extreme environmental conditions...
February 8, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/28168706/flow-field-simulations-and-hemolysis-estimates-for-the-food-and-drug-administration-critical-path-initiative-centrifugal-blood-pump
#10
Margaret L Heck, Allen Yen, Trevor A Snyder, Edgar A O'Rear, Dimitrios V Papavassiliou
The design of blood pumps for use in ventricular assist devices, which provide life-saving circulatory support in patients with heart failure, require remarkable precision and attention to detail to replicate the functionality of the native heart. The United States Food and Drug Administration (FDA) initiated a Critical Path Initiative to standardize and facilitate the use of computational fluid dynamics in the study and development of these devices. As a part of the study, a simplified centrifugal blood pump model generated by computer-aided design was released to universities and laboratories nationwide...
February 7, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28155704/the-movement-and-deposition-of-pm2-5-in-the-upper-respiratory-tract-for-the-patients-with-heart-failure-an-elementary-cfd-study
#11
Tiantian Zhang, Bin Gao, Zhixiang Zhou, Yu Chang
BACKGROUND: PM2.5 is an important factor to affect the patients with respiratory and cardiovascular diseases. Clinical studies have found that the morbidity and mortality of patients with heart failure (HF) have a close relationship with the movement and deposition state of PM2.5. One reason is that the breathing pattern of patients with HF has obvious difference with healthy people, however the effect caused by these differences on the distribution regularity of PM2.5 in the respiratory tract is still unclear...
December 28, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28155672/the-study-on-hemodynamic-effect-of-series-type-lvad-on-aortic-blood-flow-pattern-a-primary-numerical-study
#12
Qi Zhang, Bin Gao, Yu Chang
BACKGROUND: Left ventricular assist device (LVAD) has become an alternative treatment for end-stage heart failure patients. Series type of LVAD, as a novel LVAD, has attracted more and more attention. The hemodynamic effects of series type LVAD on aortic blood pattern are considered as its important characteristics; however, the precise mechanism of it is still unclear. METHODS: To clarify the hemodynamic effects of series type LVAD on aortic blood flow pattern, a comparative study on the aortic blood flow pattern and hemodynamic states were carried out numerically for two cases, including series type LVAD support and normal condition...
December 28, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28072930/left-ventricular-outflow-tract-obstruction-be-prepared
#13
J S Evans, S J Huang, A S McLean, M Nalos
The current trend to treat hypotension in critically ill patients is to place a greater emphasis on inotropic support and less on fluid resuscitation in order to limit the potential harm from fluid overload. This combination may trigger left ventricular outflow tract obstruction (LVOTO) in susceptible patients. Although LVOTO is classically described in patients with hypertrophic cardiomyopathy it has been reported in other conditions including septic shock, apical ballooning syndrome, myocardial infarction, respiratory failure, and post valvular surgery...
January 2017: Anaesthesia and Intensive Care
https://www.readbyqxmd.com/read/28039243/electrical-impedance-tomography-for-non-invasive-assessment-of-stroke-volume-variation-in-health-and-experimental-lung-injury
#14
C J C Trepte, C Phillips, J Solà, A Adler, B Saugel, S Haas, S H Bohm, D A Reuter
BACKGROUND: Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this study was to evaluate SVV measured by EIT (SVVEIT) against SVV from pulse contour analysis (SVVPC) in an experimental animal model of acute lung injury at different lung volumes...
January 2017: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/28038944/numerical-simulation-of-mitral-valve-prolapse-considering-the-effect-of-left-ventricle
#15
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/28033200/lvad-outflow-graft-angle-and-thrombosis-risk
#16
Alberto Aliseda, Venkat Keshav Chivukula, Patrick Mcgah, Anthony R Prisco, Jennifer A Beckman, Guilherme J M Garcia, Nahush A Mokadam, Claudius Mahr
This study quantifies thrombogenic potential (TP) of a wide range of left ventricular assist device (LVAD) outflow graft anastomosis angles through state-of-the-art techniques: 3D imaged-based patient-specific models created via virtual surgery and unsteady computational fluid dynamics with Lagrangian particle tracking. This study aims at clarifying the influence of a single parameter (outflow graft angle) on the thrombogenesis associated with flow patterns in the aortic root after LVAD implantation. This is an important and poorly-understood aspect of LVAD therapy, because several studies have shown strong inter and intrapatient thrombogenic variability and current LVAD implantation strategies do not incorporate outflow graft angle optimization...
January 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/27905492/high-fidelity-computational-simulation-of-thrombus-formation-in-thoratec-heartmate-ii-continuous-flow-ventricular-assist-device
#17
Wei-Tao Wu, Fang Yang, Jingchun Wu, Nadine Aubry, Mehrdad Massoudi, James F Antaki
Continuous flow ventricular assist devices (cfVADs) provide a life-saving therapy for severe heart failure. However, in recent years, the incidence of device-related thrombosis (resulting in stroke, device-exchange surgery or premature death) has been increasing dramatically, which has alarmed both the medical community and the FDA. The objective of this study was to gain improved understanding of the initiation and progression of thrombosis in one of the most commonly used cfVADs, the Thoratec HeartMate II...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27904980/a-resolved-two-way-coupled-cfd-6-dof-approach-for-predicting-embolus-transport-and-the-embolus-trapping-efficiency-of-ivc-filters
#18
Kenneth I Aycock, Robert L Campbell, Keefe B Manning, Brent A Craven
Inferior vena cava (IVC) filters are medical devices designed to provide a mechanical barrier to the passage of emboli from the deep veins of the legs to the heart and lungs. Despite decades of development and clinical use, IVC filters still fail to prevent the passage of all hazardous emboli. The objective of this study is to (1) develop a resolved two-way computational model of embolus transport, (2) provide verification and validation evidence for the model, and (3) demonstrate the ability of the model to predict the embolus-trapping efficiency of an IVC filter...
November 30, 2016: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/27878837/thrombotic-depositions-on-right-impeller-of-double-ended-centrifugal-total-artificial-heart-in-vivo
#19
Jamshid H Karimov, David J Horvath, Shinji Okano, Mark Goodin, Gengo Sunagawa, Nicole Byram, Nader Moazami, Leonard A R Golding, Kiyotaka Fukamachi
The development of total artificial heart devices is a complex undertaking that includes chronic biocompatibility assessment of the device. It is considered particularly important to assess whether device design and features can be compatible long term in a biological environment. As part of the development program for the Cleveland Clinic continuous-flow total artificial heart (CFTAH), we evaluated the device for signs of thrombosis and biological material deposition in four animals that had achieved the intended 14-, 30-, or 90-day durations in each respective experiment...
November 23, 2016: Artificial Organs
https://www.readbyqxmd.com/read/27873180/pledget-armed-sutures-affect-the-haemodynamic-performance-of-biologic-aortic-valve-substitutes-a-preliminary-experimental-and-computational-study
#20
Claudio Capelli, Chiara Corsini, Dario Biscarini, Francesco Ruffini, Francesco Migliavacca, Alfred Kocher, Guenther Laufer, Andrew M Taylor, Silvia Schievano, Martin Andreas, Gaetano Burriesci, Claus Rath
Surgical aortic valve replacement is the most common procedure of choice for the treatment of severe aortic stenosis. Bioprosthetic valves are traditionally sewed-in the aortic root by means of pledget-armed sutures during open-heart surgery. Recently, novel bioprostheses which include a stent-based anchoring system have been introduced to allow rapid implantation, therefore reducing the duration and invasiveness of the intervention. Different effects on the hemodynamics were clinically reported associated with the two technologies...
March 2017: Cardiovascular Engineering and Technology
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