scholarly journals Computational Fluid Dynamic Accuracy in Mimicking Changes in Blood Hemodynamics in Patients with Acute Type IIIb Aortic Dissection Treated with TEVAR

2018 ◽  
Vol 8 (8) ◽  
pp. 1309 ◽  
Author(s):  
Andrzej Polanczyk ◽  
Aleksandra Piechota-Polanczyk ◽  
Christoph Domenig ◽  
Josif Nanobachvili ◽  
Ihor Huk ◽  
...  
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Flow Rate ◽  
Fluid Dynamic ◽  
3D Models ◽  
Renal Arteries ◽  
Acute Type ◽  
Type Iiib ◽  
Doppler Data ◽  
Flow Through

Background: We aimed to verify the accuracy of the Computational Fluid Dynamics (CFD) algorithm for blood flow reconstruction for type IIIb aortic dissection (TBAD) before and after thoracic endovascular aortic repair (TEVAR). Methods: We made 3D models of the aorta and its branches using pre- and post-operative CT data from five patients treated for TBAD. The CFD technique was used to quantify the displacement forces acting on the aortic wall in the areas of endograft, mass flow rate/velocity and wall shear stress (WSS). Calculated results were verified with ultrasonography (USG-Doppler) data. Results: CFD results indicated that the TEVAR procedure caused a 7-fold improvement in overall blood flow through the aorta (p = 0.0001), which is in line with USG-Doppler data. A comparison of CFD results and USG-Doppler data indicated no significant change in blood flow through the analysed arteries. CFD also showed a significant increase in flow rate for thoracic trunk and renal arteries, which was in accordance with USG-Doppler data (accuracy 90% and 99.9%). Moreover, we observed a significant decrease in WSS values within the whole aorta after TEVAR compared to pre-TEVAR (1.34 ± 0.20 Pa vs. 3.80 ± 0.59 Pa, respectively, p = 0.0001). This decrease was shown by a significant reduction in WSS and WSS contours in the thoracic aorta (from 3.10 ± 0.27 Pa to 1.34 ± 0.11Pa, p = 0.043) and renal arteries (from 4.40 ± 0.25 Pa to 1.50 ± 0.22 Pa p = 0.043). Conclusions: Post-operative remodelling of the aorta after TEVAR for TBAD improved hemodynamic patterns reflected by flow, velocity and WSS with an accuracy of 99%.

scholarly journals Computational Fluid Dynamic Technique for Assessment of How Changing Character of Blood Flow and Different Value of Hct Influence Blood Hemodynamic in Dissected Aorta

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1866
Author(s):  
Andrzej Polanczyk ◽  
Aleksandra Piechota-Polanczyk ◽  
Ihor Huk ◽  
Christoph Neumayer ◽  
Julia Balcer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Blood Viscosity ◽  
Fluid Dynamic ◽  
Wall Stress ◽  
Acute Type ◽  
Type B ◽  
Type B Dissection

Using computer tomography angiography (CTA) and computational structural analysis, we present a non-invasive method of mass flow rate/velocity and wall stress analysis in type B aortic dissection. Three-dimensional (3D) computer models of the aorta were calculated using pre-operative (baseline) and post-operative CT data from 12 male patients (aged from 51 to 64 years) who were treated for acute type B dissection. A computational fluid dynamics (CFD) technique was used to quantify the displacement forces acting on the aortic wall in the areas of endografts placement. The mass flow rate and wall stress were measured and quantified using the CFD technique. The CFD model indicated the places with a lower value of blood velocity and shear rate, which corelated with higher blood viscosity and a probability of thrombus appearance. Moreover, with the increase in Hct, blood viscosity also increased, while the intensity of blood flow provoked changing viscosity values in these areas. Furthermore, the velocity gradient near the tear surface caused high wall WSS; this could lead to a decreased resistance in the aorta’s wall with further implications to a patient.

Fluid-Dynamic Pulsations and Radial Forces in a Centrifugal Pump With Different Impeller Diameters

2005 ◽  
Author(s):  
Eduardo Blanco ◽  
Rau´l Barrio ◽  
Jorge Parrondo ◽  
Jose´ Gonza´lez ◽  
Joaqui´n Ferna´ndez
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Fluid Dynamic ◽  
Front Wall ◽  
Numerical Predictions ◽  
Radial Forces ◽  
Flow Through ◽  
Radial Gap

A study is presented on the numerical computation of the unsteady flow through a single suction and single volute centrifugal pump equipped with three impellers of different outlet diameter. Computations were performed by means of the Fluent code, solving the 3D URANS equations. The study was focused on the effect of varying the impeller-volute radial gap on the flow perturbations associated to the fluid-dynamic blade-tongue interaction. In order to contrast the numerical predictions, an experimental series of tests was conducted for the pump with the bigger impeller, to obtain pressure fluctuation data along the volute front wall. Finally, the results from the numerical simulations were used to compute the radial forces at the blade passing frequency, as a function of flow-rate and blade-tongue radial gap.

scholarly journals Computational Fluid Dynamic (CFD) Simulation of Bifurcate Artery

2021 ◽  
Author(s):  
Yas Barzegar ◽  
Atrin Barzegar
Keyword(s):  
Blood Flow ◽  
Flow Pattern ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Blood Flow Rate ◽  
Heart Attacks ◽  
Fat Particles ◽  
Fluent Software ◽  
Flow Through ◽  
Computation Fluid Dynamic

Heart attacks and strokes are one of the leading causes of death in the world today, and heart attacks caused by clogged arteries that carry blood to the heart muscle are a significant part of these strokes. These are caused by the accumulation of fat particles in the walls of the arteries and the reduction of blood flow through it over a long process. The process of fat penetration in the underlying layers of the Artery wall has been the focus of many researchers, and various researches and Simulations have been done on it, in each of them, the effect of specific parameters has been considered. In the present study, the effect of blood flow rate on the flow pattern in a bifurcate artery with two ducts has been investigated using FLUENT software with Computation fluid dynamic Method. The effect of the angle between the two ducts of the Artery on the flow pattern has been investigated.

scholarly journals Treatment of Acute Stanford Type B Aortic Dissection With a Novel Cylindrical Balloon Catheter in Dogs

Circulation ◽  
2000 ◽  
Vol 102 (suppl_3) ◽  
Author(s):  
Hiromu Terai ◽  
Nobushige Tamura ◽  
Tatsuo Nakamura ◽  
Kazunobu Nishimura ◽  
Norimasa Tsutsui ◽  
...  
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Balloon Catheter ◽  
False Lumen ◽  
Aortic Blood Flow ◽  
Acute Type ◽  
Type B ◽  
Type B Aortic Dissection ◽  
True Lumen ◽  
Descending Aorta

Background —Despite recent progress in medical and surgical treatment, acute type B aortic dissection still carries a high mortality rate. We have developed a novel cylindrical balloon catheter for less invasive treatment to block the entry of the dissection and induce thrombotic occlusion of the false lumen. The balloon has the shape of a sheet when deflated but a double-cylinder shape when inflated. Therefore, aortic blood flow is maintained through the cylindrical lumen during balloon inflation. Methods and Results —Six beagle dogs underwent a left thoracotomy at the 6th intercostal space. An acute dissection of 4-cm length was created surgically on the descending aorta. The balloon catheter was inserted through the distal descending aorta and advanced to the entry site. The balloon catheter was inflated for 6 hours. The blood flow in the descending aorta and the position of the balloon was monitored by color Doppler echovasculography. Four dogs were killed humanely on the following day and 2 dogs 10 days after the surgery. The descending aorta was examined macroscopically and microscopically in all dogs. In all dogs, the false lumen was occluded by thrombi. Although no dog had clinical evidence of distal thromboembolism, 2 of the 4 dogs that were killed on the second postoperative day had fresh mural thrombi in the true lumen. Conclusions —The false lumen of the acute type B aortic dissection was effectively occluded by the novel cylindrical balloon catheter in the canine experimental model. The thrombus formation in the true lumen is the problem to be solved.

scholarly journals Shape and Enhancement Analysis as a Useful Tool for the Presentation of Blood Hemodynamic Properties in the Area of Aortic Dissection

2020 ◽  
Vol 9 (5) ◽  
pp. 1330 ◽  
Author(s):  
Andrzej Polanczyk ◽  
Aleksandra Piechota-Polanczyk ◽  
Ludomir Stefanczyk ◽  
Michal Strzelecki
Keyword(s):  
Aortic Dissection ◽  
Aortic Wall ◽  
Common Duct ◽  
Mathematical Function ◽  
Acute Type ◽  
Descending Aorta ◽  
Average Brightness ◽  
Type Iiib ◽  
Brightness Analysis ◽  
Male Patients

The aim of this study was to create a mathematical approach for blood hemodynamic description with the use of brightness analysis. Medical data was collected from three male patients aged from 45 to 65 years with acute type IIIb aortic dissection that started proximal to the left subclavian artery and involved the renal arteries. For the recognition of wall dissection areas Digital Imaging and Communications in Medicine (DICOM) data were applied. The distance from descending aorta to the diaphragm was analyzed. Each time Feret (DF) and Hydraulic (DHy) diameter were calculated. Moreover, an average brightness (BAV) was analyzed. Finally, to describe blood hemodynamic in the area of aortic wall dissection, mathematical function combining difference in brightness value and diameter for each computed tomography (CT) scan was calculated. The results indicated that DF described common duct more accurately compare to DHy. While, DHy described more accurately true and false ducts. Each time when connection of true and false duct appeared, true duct had lower brightness compare to common duct and false duct. Moreover, false duct characterized with higher brightness compare to common duct. In summary, the proposed algorithm mimics changes in brightness value for patients with acute type IIIb aortic dissection.

scholarly journals Acute type A aortic dissection involving the iliac and left renal arteries, misdiagnosed as myocardial infarction

2018 ◽  
Vol 29 (1) ◽  
pp. e9-e13 ◽  
Author(s):  
Paul Nkemtendong Tolefac ◽  
Anastase Dzudie ◽  
Sidick Mouliom ◽  
Leopold Aminde ◽  
Romuald Hentchoya ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Aortic Dissection ◽  
Type A ◽  
Renal Arteries ◽  
Acute Type ◽  
Type A Aortic Dissection

scholarly journals The Effect of Slip Velocity on Unsteady Peristalsis MHD Blood Flow through a Constricted Artery Experiencing Body Acceleration

2019 ◽  
Vol 24 (3) ◽  
pp. 645-659 ◽  
Author(s):  
J. Nandal ◽  
S. Kumari ◽  
R. Rathee
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Axial Velocity ◽  
Slip Velocity ◽  
Volumetric Flow Rate ◽  
Body Acceleration ◽  
Stenosed Artery ◽  
Flow Through

Abstract In this analysis, we present a theoretical study to examine the combined effect of both slip velocity and periodic body acceleration on an unsteady generalized non-Newtonian blood flow through a stenosed artery with permeable wall. A constant transverse magnetic field is applied on the peristaltic flow of blood, treating it as an elastico-viscous, electrically conducting and incompressible fluid. Appropriate transformation methods are adopted to solve the unsteady non-Newtonian axially symmetric momentum equation in the cylindrical polar coordinate system with suitably prescribed conditions. To validate the applicability of the proposed analysis, analytical expressions for the axial velocity, fluid acceleration, wall shear stress and volumetric flow rate are computed and for having an adequate insight to blood flow behavior through a stenosed artery, graphs have been plotted with varying values of flow variables, to analyse the influence of the axial velocity, wall shear stress and volumetric flow rate of streaming blood.

COUPLED 0D AND CFD SIMULATION OF BLOOD FLOW THROUGH A STANFORD TYPE B AORTIC DISSECTION

2012 ◽  
Vol 45 ◽  
pp. S21
Author(s):  
Mona Alimohammadi ◽  
Stavroula Balabani ◽  
Vanessa Diaz-Zuccarini
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Cfd Simulation ◽  
Type B ◽  
Type B Aortic Dissection ◽  
Flow Through ◽  
Stanford Type B

Milking frequency alters the milk yield and mammary blood flow response to intra-mammary infusion of insulin-like growth factor-I in the goat

1992 ◽  
Vol 135 (2) ◽  
pp. 311-316 ◽  
Author(s):  
C. G. Prosser ◽  
S. R. Davis
Keyword(s):  
Blood Flow ◽  
Milk Yield ◽  
Flow Rate ◽  
Yield Response ◽  
Arterial Infusion ◽  
Blood Flow Response ◽  
Flow Response ◽  
Igf I ◽  
Flow Through ◽  
Milking Frequency

ABSTRACT The milk yield and mammary blood flow responses to close-arterial, intra-mammary infusion of IGF-I were investigated in five Saanen goats milked frequently or normally the day before. Animals were infused for 6 h with recombinant human IGF-I (1·3 nmol/min) and milked hourly following i.v. injection of oxytocin beginning 2 h before infusion and then every 2 h. On one occasion animals were milked five times (after i.v. injection of oxytocin) on the day before infusion and on the other they were milked twice, without oxytocin. The ratio of milk yield from the infused to that from non-infused gland increased by 17 ±4% (mean ± s.e.m.) in goats milked twice the day before infusion and by 6 ± 2% when the infusion was preceded by frequent milking. Maximal responses were obtained 4 h after the start of the infusion and differed significantly (P<0·05), according to pretreatment milking. Blood flow through the infused gland rose in parallel to the milk yield response. At 5 h, when maximal levels were achieved, blood flow was 182 ±23% of the pre-infusion flow rate following twice-daily milking and 139 ± 3% of the pre-infusion flow rate following more frequent milk removal. Thus, more frequent milk removal on the day before close-arterial infusion of IGF-I attenuated both the milk yield and mammary blood-flow response to the infusion of IGF-I. Journal of Endocrinology (1992) 135, 311–316

scholarly journals A Fluid-Structure Interaction Finite Element Analysis of Pulsatile Blood Flow Through a Compliant Stenotic Artery

1999 ◽  
Vol 121 (4) ◽  
pp. 361-369 ◽  
Author(s):  
M. Bathe ◽  
R. D. Kamm
Keyword(s):  
Finite Element ◽  
Blood Flow ◽  
Pressure Drop ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Large Strain ◽  
Pulsatile Blood Flow ◽  
Element Analysis ◽  
Area Reduction ◽  
Flow Through

A new model is used to analyze the fully coupled problem of pulsatile blood flow through a compliant, axisymmetric stenotic artery using the finite element method. The model uses large displacement and large strain theory for the solid, and the full Navier-Stokes equations for the fluid. The effect of increasing area reduction on fluid dynamic and structural stresses is presented. Results show that pressure drop, peak wall shear stress, and maximum principal stress in the lesion all increase dramatically as the area reduction in the stenosis is increased from 51 to 89 percent. Further reductions in stenosis cross-sectional area, however, produce relatively little additional change in these parameters due to a concomitant reduction in flow rate caused by the losses in the constriction. Inner wall hoop stretch amplitude just distal to the stenosis also increases with increasing stenosis severity, as downstream pressures are reduced to a physiological minimum. The contraction of the artery distal to the stenosis generates a significant compressive stress on the downstream shoulder of the lesion. Dynamic narrowing of the stenosis is also seen, further augmenting area constriction at times of peak flow. Pressure drop results are found to compare well to an experimentally based theoretical curve, despite the assumption of laminar flow.

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