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Fluid dynamics of the heart

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https://www.readbyqxmd.com/read/29677037/small-left-ventricular-size-is-an-independent-risk-factor-for-ventricular-assist-device-thrombosis
#1
Venkat Keshav Chivukula, Jennifer A Beckman, Anthony R Prisco, Shin Lin, Todd F Dardas, Richard K Cheng, Stephen D Farris, Jason W Smith, Nahush A Mokadam, Claudius Mahr, Alberto Aliseda
The prevalence of ventricular assist device (VAD) therapy has continued to increase due to a stagnant donor supply and growing advanced heart failure (HF) population. We hypothesize that left ventricular (LV) size strongly influences biocompatibility and risk of thrombosis. Unsteady computational fluid dynamics (CFD) was used in conjunction with patient-derived computational modeling and virtual surgery with a standard, apically implanted inflow cannula. A dual-focus approach of evaluating thrombogenicity was employed: platelet-based metrics to characterize the platelet environment and flow-based metrics to investigate hemodynamics...
April 18, 2018: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/29675697/computational-fluid-dynamics-assessment-associated-with-transcatheter-heart-valve-prostheses-a-position-paper-of-the-iso-working-group
#2
REVIEW
Zhenglun Alan Wei, Simon Johannes Sonntag, Milan Toma, Shelly Singh-Gryzbon, Wei Sun
The governing international standard for the development of prosthetic heart valves is International Organization for Standardization (ISO) 5840. This standard requires the assessment of the thrombus potential of transcatheter heart valve substitutes using an integrated thrombus evaluation. Besides experimental flow field assessment and ex vivo flow testing, computational fluid dynamics is a critical component of this integrated approach. This position paper is intended to provide and discuss best practices for the setup of a computational model, numerical solving, post-processing, data evaluation and reporting, as it relates to transcatheter heart valve substitutes...
April 19, 2018: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/29666072/left-ventricular-assist-device-inflow-cannula-angle-and-thrombosis-risk
#3
Venkat Keshav Chivukula, Jennifer A Beckman, Anthony R Prisco, Todd Dardas, Shin Lin, Jason W Smith, Nahush A Mokadam, Alberto Aliseda, Claudius Mahr
BACKGROUND: As heart failure prevalence continues to increase in the setting of a static donor supply, left ventricular assist device (LVAD) therapy for end-stage heart failure continues to grow. Anecdotal evidence suggests that malalignment of the LVAD inflow cannula may increase thrombosis risk, but this effect has not been explored mechanistically or quantified statistically. Our objective is to elucidate the impact of surgical angulation of the inflow cannula on thrombogenicity. METHODS AND RESULTS: Unsteady computational fluid dynamics is used in conjunction with computational modeling and virtual surgery to model flow through the left ventricle for 5 different inflow cannula angulations...
April 2018: Circulation. Heart Failure
https://www.readbyqxmd.com/read/29617784/the-influence-of-different-inflow-configurations-on-computational-fluid-dynamics-in-a-novel-three-leaflet-mechanical-heart-valve-prosthesis
#4
Hans-Hinrich Sievers, Kathrin Schubert, Ashkan Jamali, Michael Scharfschwerdt
OBJECTIVES: A novel mechanical heart valve was developed with a special focus on avoiding anticoagulation. Computational fluid dynamics were used for the research design. Here, the effect of different anatomical inflow geometries on flow characteristics is evaluated. METHODS: Flow and pressure simulations were performed on a novel 3-leaflet mechanical heart valve in a fully open position at 2 flow rates related to the peak and end-systolic flow. The computational fluid dynamics model was designed according to 4 different (1 cylindrical, 3 conical with increasing diameter) anatomical configurations of the left ventricular outflow tract derived from an inverse heart model...
March 30, 2018: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/29572879/patient-specific-atrial-hemodynamics-of-a-double-lumen-neonatal-cannula-in-correct-caval-position
#5
Jamil Muhammad, Mohammad Rezaeimoghaddam, Bilgesu Cakmak, Reza Rasooli, Ece Salihoglu, Yahya Yıldız, Kerem Pekkan
Clinical success of pediatric veno-venous (VV) extracorporeal membrane oxygenation (ECMO) is associated with the double lumen cannula cardiovascular device design as well as its anatomic orientation in the atrium. The positions of cannula ports with respect to the vena cavae and the tricuspid valve are believed to play a significant role on device hemodynamics. Despite various improvements in ECMO catheters, especially for the neonatal and congenital heart patients, it is still challenging to select a catalogue size that would fit to most patients optimally...
March 23, 2018: Artificial Organs
https://www.readbyqxmd.com/read/29568740/feasibility-of-computational-fluid-dynamics-for-evaluating-the-intraventricular-hemodynamics-in-single-right-ventricle-based-on-echocardiographic-images
#6
Li-Jun Chen, Zhi-Rong Tong, Qian Wang, Yu-Qi Zhang, Jin-Long Liu
This study introduced a combined computational fluid dynamics (CFD) and echocardiography methodology to simulate blood flow in the single right ventricle (SRV) and normal ventricles to study the intraventricular flow. Derived from echocardiographic image loops, CFD-based three-dimensional (3D) flow models of normal subject's left ventricle (LV) and right ventricle (RV) and SRV with and without heart failure at three characteristic diastolic statuses were reconstructed. The CFD derived morphological and functional measurements in normal ventricles and the SRV were validated with echocardiography...
2018: BioMed Research International
https://www.readbyqxmd.com/read/29547668/three-dimensional-flow-structures-past-a-bio-prosthetic-valve-in-an-in-vitro-model-of-the-aortic-root
#7
David Hasler, Dominik Obrist
The flow field past a prosthetic aortic valve comprises many details that indicate whether the prosthesis is functioning well or not. It is, however, not yet fully understood how an optimal flow scenario would look, i.e. which subtleties of the fluid dynamics in place are essential regarding the durability and compatibility of a prosthetic valve. In this study, we measured and analyzed the 3D flow field in the vicinity of a bio-prosthetic heart valve in function of the aortic root size. The measurements were conducted within aortic root phantoms of different size, mounted in a custom-built hydraulic setup, which mimicked physiological flow conditions in the aorta...
2018: PloS One
https://www.readbyqxmd.com/read/29512419/effect-of-heliox-on-respiratory-outcomes-during-rigid-bronchoscopy-in-term-lambs
#8
Justin C Sowder, Mar Janna Dahl, Kaitlin R Zuspan, Kurt H Albertine, Donald M Null, Mitchell D Barneck, J Fredrik Grimmer
Objective To (1) compare physiologic changes during rigid bronchoscopy during spontaneous and mechanical ventilation and (2) evaluate the efficacy of a helium-oxygen (heliox) gas mixture as compared with room air during rigid bronchoscopy. Study Design Crossover animal study evaluating physiologic parameters during rigid bronchoscopy. Outcomes were compared with predicted computational fluid analysis. Setting Simulated ventilation via computational fluid dynamics analysis and term lambs undergoing rigid bronchoscopy...
March 1, 2018: Otolaryngology—Head and Neck Surgery
https://www.readbyqxmd.com/read/29512410/experimental-measurement-and-numerical-modelling-of-dye-washout-for-investigation-of-blood-residence-time-in-ventricular-assist-devices
#9
Alessandra Molteni, Zubair Ph Masri, Kenny Wq Low, Haitham N Yousef, Johann Sienz, Katharine H Fraser
Ventricular assist devices have become the standard therapy for end-stage heart failure. However, their use is still associated with severe adverse events related to the damage done to the blood by fluid dynamic stresses. This damage relates to both the stress magnitude and the length of time the blood is exposed to that stress. We created a dye washout technique which combines experimental and numerical approaches to measure the washout times of ventricular assist devices. The technique was used to investigate washout characteristics of three commercially available and clinically used ventricular assist devices: the CentriMag, HVAD and HeartMate II...
March 1, 2018: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/29512059/patient-specific-cardiovascular-computational-modeling-diversity-of-personalization-and-challenges
#10
REVIEW
Richard A Gray, Pras Pathmanathan
Patient-specific computer models have been developed representing a variety of aspects of the cardiovascular system spanning the disciplines of electrophysiology, electromechanics, solid mechanics, and fluid dynamics. These physiological mechanistic models predict macroscopic phenomena such as electrical impulse propagation and contraction throughout the entire heart as well as flow and pressure dynamics occurring in the ventricular chambers, aorta, and coronary arteries during each heartbeat. Such models have been used to study a variety of clinical scenarios including aortic aneurysms, coronary stenosis, cardiac valvular disease, left ventricular assist devices, cardiac resynchronization therapy, ablation therapy, and risk stratification...
March 6, 2018: Journal of Cardiovascular Translational Research
https://www.readbyqxmd.com/read/29508416/the-progress-in-the-novel-pediatric-rotary-blood-pump-sputnik-development
#11
Dmitry Telyshev, Maxim Denisov, Alexander Pugovkin, Sergey Selishchev, Igor Nesterenko
In this work, the study results of an implantable pediatric rotary blood pump (PRBP) are presented. They show the results of the numerical simulation of fluid flow rates in the pump. The determination method of the backflows and stagnation regions is represented. The operating points corresponding to fluid flow rates of 1, 3, and 5 L/min for 75-80 mm Hg pressure head are investigated. The study results have shown that use of the pump in the 1 L/min operating point can potentially lead to the appearance of backflows and stagnation regions...
March 6, 2018: Artificial Organs
https://www.readbyqxmd.com/read/29500919/simulation-of-personalised-haemodynamics-by-various-mounting-positions-of-a-prosthetic-valve-using-computational-fluid-dynamics
#12
Markus Bongert, Marius Geller, Werner Pennekamp, Volkmar Nicolas
Diseases of the cardiovascular system account for nearly 42% of all deaths in the European Union. In Germany, approximately 12,000 patients receive surgical replacement of the aortic valve due to heart valve disease alone each year. A three-dimensional (3D) numerical model based on patient-specific anatomy derived from four-dimensional (4D) magnetic resonance imaging (MRI) data was developed to investigate preoperatively the flow-induced impact of mounting positions of aortic prosthetic valves to select the best orientation for individual patients...
March 3, 2018: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/29458381/cardiac-fluid-dynamics-meets-deformation-imaging
#13
REVIEW
Matteo Dal Ferro, Davide Stolfo, Valerio De Paris, Pierluigi Lesizza, Renata Korcova, Dario Collia, Giovanni Tonti, Gianfranco Sinagra, Gianni Pedrizzetti
Cardiac function is about creating and sustaining blood in motion. This is achieved through a proper sequence of myocardial deformation whose final goal is that of creating flow. Deformation imaging provided valuable contributions to understanding cardiac mechanics; more recently, several studies evidenced the existence of an intimate relationship between cardiac function and intra-ventricular fluid dynamics. This paper summarizes the recent advances in cardiac flow evaluations, highlighting its relationship with heart wall mechanics assessed through the newest techniques of deformation imaging and finally providing an opinion of the most promising clinical perspectives of this emerging field...
February 20, 2018: Cardiovascular Ultrasound
https://www.readbyqxmd.com/read/29423504/nonlinear-dynamics-of-dacron-aortic-prostheses-conveying-pulsatile-flow
#14
Eleonora Tubaldi, Michael Paidoussis, Marco Amabili
This study addresses the dynamic response to pulsatile physiological blood flow and pressure of a woven Dacron graft currently used in thoracic aortic surgery. The model of the prosthesis assumes a cylindrical orthotropic shell described by means of nonlinear Novozhilov shell theory. The blood flow is modeled as Newtonian pulsatile flow, and unsteady viscous effects are included. Coupled fluid-structure Lagrange equations for open systems with wave propagation subject to pulsatile flow are applied. Physiological waveforms of blood pressure and velocity are approximated with the first eight harmonics of the corresponding Fourier series...
February 8, 2018: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/29373336/competing-flow-between-partial-circulatory-support-and-native-cardiac-output-a-clinical-computational-fluid-dynamics-study
#15
Jennifer Engelke, Christof Karmonik, Fabian Rengier, Sasan Partovi, Aron-Frederik Popov, Anja Osswald, Rawa Arif, Bastian Schmack, Philip Raake, André R Simon, Andreas Doesch, Alexander Weymann, Joachim Lotz, Matthias Karck, Arjang Ruhparwar
Partial circulatory support is a promising concept for the treatment of heart failure patients. A better understanding of induced hemodynamic changes is essential for optimizing treatment efficacy. Computational fluid dynamics (CFD) is an alternative method to gain insight into flow phenomena difficult to obtain in vivo. In 10 patients implanted with a Circulite Synergy Micro-pump (HeartWare) (a continuous flow partial circulatory assist device connecting the left atrium to the right subclavian artery), transient CFD simulations were performed...
October 25, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/29368625/perioperative-fluid-management-in-kidney-transplantation-a-black-box
#16
REVIEW
Maria Helena Calixto Fernandes, Thomas Schricker, Sheldon Magder, Roupen Hatzakorzian
The incidence of delayed graft function in patients undergoing kidney transplantation remains significant. Optimal fluid therapy has been shown to decrease delayed graft function after renal transplantation. Traditionally, the perioperative volume infusion regimen in this patient population has been guided by central venous pressure as an estimation of the patient's volume status and mean arterial pressure, but this is based on sparse evidence from mostly retrospective observational studies. Excessive volume infusion to the point of no further fluid responsiveness can damage the endothelial glycocalyx and is no longer considered to be the best approach...
January 25, 2018: Critical Care: the Official Journal of the Critical Care Forum
https://www.readbyqxmd.com/read/29368394/complex-coronary-bifurcation-treatment-by-a-novel-stenting-technique-bench-test-fluid-dynamic-study-and-clinical-outcomes
#17
Gianluca Rigatelli, Marco Zuin, Fabio Dell'Avvocata, Dobrin Vassilev, Ramesh Daggubati, Thach Nguyen, Minh Trí Nhân Nguyễn, Nicolas Foin
OBJECTIVES: We assess the mid-term outcomes of ultrathin biodegradable polymer double stenting using a very minimal crushing (Nano-Crush) technique in large complex coronary bifurcation. BACKGROUND: Complex bifurcations have been suggested to be better approached by a planned double stent technique. METHODS: Two hundred and five consecutive patients (107 males and 98 females) referred for large complex coronary bifurcation percutaneous coronary interventions were enrolled...
January 25, 2018: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/29354002/cerebrospinal-fluid-dynamics-in-patients-with-multiple-sclerosis-the-role-of-phase-contrast-mri-in-the-differential-diagnosis-of-active-and-chronic-disease
#18
Serkan Öner, Ayşegül Sağır Kahraman, Cemal Özcan, Zeynep Maraş Özdemir, Serkan Ünlü, Özden Kamışlı, Zülal Öner
Objective: Multiple sclerosis (MS) is an inflammatory disease characterized by demyelinating plaques in the white matter. Chronic cerebrospinal venous insufficiency (CCSVI) has been proposed as a new hypothesis for the etiopathogenesis of MS disease. MS-CCSVI includes a significant decrease of cerebrospinal fluid (CSF) flow through the cerebral aqueduct secondary to an impaired venous outflow from the central nervous system. This study aimed to determine whether CSF flow dynamics are affected in MS patients and the contributions to differential diagnosis in active and chronic disease using phase-contrast magnetic resonance imaging (PC-MRI)...
January 2018: Korean Journal of Radiology: Official Journal of the Korean Radiological Society
https://www.readbyqxmd.com/read/29305610/flow-structure-interaction-simulations-of-the-aortic-heart-valve-at-physiologic-conditions-the-role-of-tissue-constitutive-model
#19
Anvar Gilmanov, Henryk Stolarski, Fotis Sotiropoulos
The blood flow patterns in the region around the aortic valve depend on the geometry of the aorta and on the complex flow-structure interaction between the pulsatile flow and the valve leaflets. Consequently, the flow depends strongly on the constitutive properties of the tissue, which can be expected to vary between healthy and diseased heart valves or native and prosthetic valves. The main goal of this work is to qualitatively demonstrate that the choice of the constitutive model of the aortic valve is critical in analysis of heart hemodynamics...
April 1, 2018: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/29285347/patient-specific-simulations-for-planning-treatment-in-congenital-heart-disease
#20
Claudio Capelli, Emilie Sauvage, Giuliano Giusti, Giorgia M Bosi, Hopewell Ntsinjana, Mario Carminati, Graham Derrick, Jan Marek, Sachin Khambadkone, Andrew M Taylor, Silvia Schievano
Patient-specific computational models have been extensively developed over the last decades and applied to investigate a wide range of cardiovascular problems. However, translation of these technologies into clinical applications, such as planning of medical procedures, has been limited to a few single case reports. Hence, the use of patient-specific models is still far from becoming a standard of care in clinical practice. The aim of this study is to describe our experience with a modelling framework that allows patient-specific simulations to be used for prediction of clinical outcomes...
February 6, 2018: Interface Focus
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