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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/28072930/left-ventricular-outflow-tract-obstruction-be-prepared
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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...
November 21, 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27866678/patient-specific-cfd-models-for-intraventricular-flow-analysis-from-3d-ultrasound-imaging-comparison-of-three-clinical-cases
#9
A M Bavo, A M Pouch, J Degroote, J Vierendeels, J H Gorman, R C Gorman, P Segers
BACKGROUND: As the intracardiac flow field is affected by changes in shape and motility of the heart, intraventricular flow features can provide diagnostic indications. Ventricular flow patterns differ depending on the cardiac condition and the exploration of different clinical cases can provide insights into how flow fields alter in different pathologies. METHODS: In this study, we applied a patient-specific computational fluid dynamics model of the left ventricle and mitral valve, with prescribed moving boundaries based on transesophageal ultrasound images for three cardiac pathologies, to verify the abnormal flow patterns in impaired hearts...
January 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27863743/in-vitro-and-in-silico-approaches-to-quantify-the-effects-of-the-mitraclip-%C3%A2-system-on-mitral-valve-function
#10
Francesco Sturla, Riccardo Vismara, Michal Jaworek, Emiliano Votta, Paolo Romitelli, Omar A Pappalardo, Federico Lucherini, Carlo Antona, Gianfranco B Fiore, Alberto Redaelli
Mitraclip(®) implantation is widely used as a valid alternative to conventional open-chest surgery in high-risk patients with severe mitral valve (MV) regurgitation. Although effective in reducing mitral regurgitation (MR) in the majority of cases, the clip implantation produces a double-orifice area that can result in altered MV biomechanics, particularly in term of hemodynamics and mechanical stress distribution on the leaflets. In this scenario, we combined the consistency of in vitro experimental platforms with the versatility of numerical simulations to investigate clip impact on MV functioning...
January 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27858374/prediction-of-fluid-responsiveness-an-update
#11
REVIEW
Xavier Monnet, Paul E Marik, Jean-Louis Teboul
In patients with acute circulatory failure, the decision to give fluids or not should not be taken lightly. The risk of overzealous fluid administration has been clearly established. Moreover, volume expansion does not always increase cardiac output as one expects. Thus, after the very initial phase and/or if fluid losses are not obvious, predicting fluid responsiveness should be the first step of fluid strategy. For this purpose, the central venous pressure as well as other "static" markers of preload has been used for decades, but they are not reliable...
December 2016: Annals of Intensive Care
https://www.readbyqxmd.com/read/27844463/fluid-structure-interaction-study-of-transcatheter-aortic-valve-dynamics-using-smoothed-particle-hydrodynamics
#12
Wenbin Mao, Kewei Li, Wei Sun
Computational modeling of heart valve dynamics incorporating both fluid dynamics and valve structural responses has been challenging. In this study, we developed a novel fully-coupled fluid-structure interaction (FSI) model using smoothed particle hydrodynamics (SPH). A previously developed nonlinear finite element (FE) model of transcatheter aortic valves (TAV) was utilized to couple with SPH to simulate valve leaflet dynamics throughout the entire cardiac cycle. Comparative simulations were performed to investigate the impact of using FE-only models vs...
December 2016: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/27832045/proof-of-concept-of-an-endoscopic-sutureless-valve-sizer
#13
Marco Vola, Juan Pablo Maureira, Vito Giovanni Ruggieri, Jean-François Fuzellier, Salvatore Campisi, Jean-Pierre Favre, Antoine Gerbay, Thierry A Folliguet
OBJECTIVE: In this paper, we present an endoscopic expandable sizer conceived to allow thoracoscopic aortic valve replacement with a sutureless prosthesis using a dynamic sizing of the aortic annulus. METHODS: Ten aortic torsos were prepared using a five-trocar thoracoscopic setting. Once the aortotomy was performed and the aortic valve leaflets removed, the technical feasibility of the endoscopic sizing (introduction into the trocar, expansion into the aortic annulus, determination of the valve size, and retraction) with the device was assessed...
September 2016: Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery
https://www.readbyqxmd.com/read/27824560/assessing-the-performance-of-ultrafast-vector-flow-imaging-in-the-neonatal-heart-via-multiphysics-modeling-and-in-vitro-experiments
#14
Joris Van Cauwenberge, Lasse Lovstakken, Solveig Fadnes, Alfonso Rodriguez-Morales, Jan Vierendeels, Patrick Segers, Abigail Swillens
Ultrafast vector flow imaging would benefit newborn patients with congenital heart disorders, but still requires thorough validation before translation to clinical practice. This paper investigates 2-D speckle tracking (ST) of intraventricular blood flow in neonates when transmitting diverging waves at ultrafast frame rate. Computational and in vitro studies enabled us to quantify the performance and identify artifacts related to the flow and the imaging sequence. First, synthetic ultrasound images of a neonate's left ventricular flow pattern were obtained with the ultrasound simulator Field II by propagating point scatterers according to 3-D intraventricular flow fields obtained with computational fluid dynamics (CFD)...
November 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27815409/a-new-beating-heart-mitral-and-aortic-valve-assessment-model-with-implications-for-valve-intervention-training
#15
Wobbe Bouma, Jayant S Jainandunsing, Arash Khamooshian, Pim van der Harst, Massimo A Mariani, Ehsan Natour
OBJECTIVES: A thorough understanding of mitral and aortic valve motion dynamics is essential in mastering the skills necessary for performing successful valve intervention (open or transcatheter repair or replacement). We describe a reproducible and versatile beating-heart mitral and aortic valve assessment and valve intervention training model in human cadavers. METHODS: The model is constructed by bilateral ligation of the pulmonary veins, ligation of the supra-aortic arteries, creating a shunt between the descending thoracic aorta and the left atrial appendage with a vascular prosthesis, anastomizing a vascular prosthesis to the apex and positioning an intra-aortic balloon pump (IABP) in the vascular prosthesis, cross-clamping the descending thoracic aorta, and finally placing a fluid line in the shunt prosthesis...
November 3, 2016: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/27738801/goal-directed-fluid-therapy-decreases-postoperative-morbidity-but-not-mortality-in-major-non-cardiac-surgery-a-meta-analysis-and-trial-sequential-analysis-of-randomized-controlled-trials
#16
Anirban Som, Souvik Maitra, Sulagna Bhattacharjee, Dalim K Baidya
BACKGROUND AND AIMS: Optimum perioperative fluid administration may improve postoperative outcome after major surgery. This meta-analysis and systematic review has been aimed to determine the effect of dynamic goal directed fluid therapy (GDFT) on postoperative morbidity and mortality in non-cardiac surgical patients. MATERIAL AND METHODS: Meta-analysis of published prospective randomized controlled trials where GDFT based on non-invasive flow based hemodynamic measurement has been compared with a standard care...
October 13, 2016: Journal of Anesthesia
https://www.readbyqxmd.com/read/27663769/fluid-mechanics-of-human-fetal-right-ventricles-from-image-based-computational-fluid-dynamics-using-4d-clinical-ultrasound-scans
#17
Hadi Wiputra, Chang Quan Lai, Guat Ling Lim, Joel Jia Wei Heng, Lan Guo, Sanah Merchant Soomar, Hwa Liang Leo, Arijit Biwas, Citra Nurfarah Zaini Mattar, Choon Hwai Yap
There are 0.6-1.9% of US children who were born with congenital heart malformations. Clinical and animal studies suggest that abnormal blood flow forces might play a role in causing these malformation, highlighting the importance of understanding the fetal cardiovascular fluid mechanics. We performed computational fluid dynamics simulations of the right ventricles, based on four-dimensional ultrasound scans of three 20-wk-old normal human fetuses, to characterize their flow and energy dynamics. Peak intraventricular pressure gradients were found to be 0...
December 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27659877/physiological-mechanisms-of-pulmonary-hypertension
#18
REVIEW
David H MacIver, Ismail Adeniran, Iain R MacIver, Alistair Revell, Henggui Zhang
Pulmonary hypertension is usually related to obstruction of pulmonary blood flow at the level of the pulmonary arteries (eg, pulmonary embolus), pulmonary arterioles (idiopathic pulmonary hypertension), pulmonary veins (pulmonary venoocclusive disease) or mitral valve (mitral stenosis and regurgitation). Pulmonary hypertension is also observed in heart failure due to left ventricle myocardial diseases regardless of the ejection fraction. Pulmonary hypertension is often regarded as a passive response to the obstruction to pulmonary flow...
October 2016: American Heart Journal
https://www.readbyqxmd.com/read/27618494/patient-specific-simulation-of-cardiac-blood-flow-from-high-resolution-ct
#19
Jonas Lantz, Lilian Henriksson, Anders Persson, Matts Karlsson, Tino Ebbers
Cardiac hemodynamics can be computed from medical imaging data, and results could potentially aid in cardiac diagnosis and treatment optimization. However, simulations are often based on simplified geometries, ignoring features such as papillary muscles and trabeculae due to their complex shape, limitations in image acquisitions, and challenges in computational modeling. This severely hampers the use of computational fluid dynamics in clinical practice. The overall aim of this study was to develop a novel numerical framework that incorporated these geometrical features...
September 12, 2016: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/27599255/diagnosis-and-treatment-of-lymphatic-plastic-bronchitis-in-adults-using-advanced-lymphatic-imaging-and-percutaneous-embolization
#20
Maxim G Itkin, Francis X McCormack, Yoav Dori
RATIONALE: Plastic bronchitis is a condition characterized by expectoration of branching bronchial casts. Although the mechanism of cast formation in adults with plastic bronchitis remains poorly understood, abnormal pulmonary lymphatic flow resulting in molding of congealing lymphatic fluids in the airway has been documented as a cause of the disease in children with congenital heart disease. OBJECTIVES: To use advanced lymphatic imaging techniques, including dynamic contrast-enhanced magnetic resonance (MR) lymphangiography (DCMRL) and intranodal lymphangiography, to investigate the mechanism of cast formation in adult patients with plastic bronchitis, and to evaluate the therapeutic outcome of percutaneous lymphatic embolization for these patients...
October 2016: Annals of the American Thoracic Society
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