scholarly journals Esophageal Retention with Retrograde Flow Through Pharyngoesophageal Segment Following Swallowing

2020 ◽  
Author(s):  
Keyword(s):  
Retrograde Flow ◽  
Pharyngoesophageal Segment ◽  
Flow Through

Truncus arteriosus with retrograde aortic flow: a unique case

2020 ◽  
Vol 30 (2) ◽  
pp. 284-286
Author(s):  
Matthew A. Solomon ◽  
Bijoy Thattaliyath ◽  
Ravi Ashwath
Keyword(s):  
Blood Flow ◽  
Congenital Heart Defect ◽  
Congenital Heart ◽  
Ascending Aorta ◽  
Outflow Tract ◽  
Aortic Flow ◽  
Truncus Arteriosus ◽  
Retrograde Flow ◽  
Unique Case ◽  
Flow Through

AbstractTruncus arteriosus is a rare cyanotic congenital heart defect that involves septation failure of the heart’s main arterial outflow tract. Varying morphologies of the truncal valve and aorta have been reported; however, the ascending aorta is typically supplied via anterograde blood flow through the truncal valve. We present the first reported case of neonatal truncus arteriosus with the ascending aorta being supplied entirely by retrograde flow.

Retrograde suction decompression of giant paraclinoidal aneurysms

1990 ◽  
Vol 73 (2) ◽  
pp. 305-306 ◽  
Author(s):  
H. Hunt Batjer ◽  
Duke S. Samson
Keyword(s):  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Ophthalmic Artery ◽  
Internal Carotid ◽  
Retrograde Flow ◽  
Local Circulation ◽  
Wall Suction ◽  
Content Type ◽  
Flow Through ◽  
Cervical Internal Carotid Artery

✓ Giant paraclinoidal carotid artery aneurysms frequently require temporary interruption of local circulation to facilitate safe occlusion. Due to brisk retrograde flow through the ophthalmic artery and cavernous branches, simple trapping of the aneurysm by cervical internal carotid artery clamping and intracranial distal clipping may not adequately soften the lesion. The authors describe a retrograde suction method of aspiration of this collateral supply which they have used in over 40 cases. After temporary trapping, a No. 18 angiocatheter is inserted into the cervical internal carotid artery. This catheter is then connected to a wall suction point allowing rapid aneurysm deflation. This technique, accomplished by the surgical assistant, permits the surgeon the freedom to use both hands in dealing quickly with the aneurysm.

The Effect of Proximal Artery Flow on the Hemodynamics at the Distal Anastomosis of a Vascular Bypass Graft: Computational Study

2001 ◽  
Vol 123 (3) ◽  
pp. 277-283 ◽  
Author(s):  
Stephanie M. Kute ◽  
David A. Vorp
Keyword(s):  
Flow Condition ◽  
Stokes Equations ◽  
Bypass Graft ◽  
Distal Anastomosis ◽  
Retrograde Flow ◽  
Vascular Bypass ◽  
Flow Through ◽  
Artery Flow ◽  
Flow Case ◽  
Zero Flow

The formation of distal anastomotic intimal hyperplasia (IH), one common mode of bypass graft failure, has been shown to occur in the areas of disturbed flow particular to this site. The nature of the flow in the segment of artery proximal to the distal anastomosis varies from case to case depending on the clinical situation presented. A partial stenosis of a bypassed arterial segment may allow residual prograde flow through the proximal artery entering the distal anastomosis of the graft. A complete stenosis may allow for zero flow in the proximal artery segment or retrograde flow due to the presence of small collateral vessels upstream. Although a number of investigations on the hemodynamics at the distal anastomosis of an end-to-side bypass graft have been conducted, there has not been a uniform treatment of the proximal artery flow condition. As a result, direct comparison of results from study to study may not be appropriate. The purpose of this work was to perform a three-dimensional computational investigation to study the effect of the proximal artery flow condition (i.e., prograde, zero, and retrograde flow) on the hemodynamics at the distal end-to-side anastomosis. We used the finite volume method to solve the full Navier–Stokes equations for steady flow through an idealized geometry of the distal anastomosis. We calculated the flow field and local wall shear stress (WSS) and WSS gradient (WSSG) everywhere in the domain. We also calculated the severity parameter (SP), a quantification of hemodynamic variation, at the anastomosis. Our model showed a marked difference in both the magnitude and spatial distribution of WSS and WSSG. For example, the maximum WSS magnitude on the floor of the artery proximal to the anastomosis for the prograde and zero flow cases is 1.8 and 3.9 dynes/cm2, respectively, while it is increased to 10.3 dynes/cm2 in the retrograde flow case. Similarly, the maximum value of WSSG magnitude on the floor of the artery proximal to the anastomosis for the prograde flow case is 4.9 dynes/cm3, while it is increased to 13.6 and 24.2 dynes/cm3, respectively, in the zero and retrograde flow cases. The value of SP is highest for the retrograde flow case (13.7 dynes/cm3) and 8.1 and 12.1 percent lower than this for the prograde (12.6 dynes/cm3) and zero (12.0 dynes/cm3) flow cases, respectively. Our model results suggest that the flow condition in the proximal artery is an important determinant of the hemodynamics at the distal anastomosis of end-to-side vascular bypass grafts. Because hemodynamic forces affect the response of vascular endo- thelial cells, the flow situation in the proximal artery may affect IH formation and, therefore, long-term graft patency. Since surgeons have some control over the flow condition in the proximal artery, results from this study could help determine which flow condition is clinically optimal.

Myocardial Distribution of Retrograde Flow through the Coronary Sinus of the Excised Normal Canine Heart

1986 ◽  
Vol 41 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Katsuhisa Shiki ◽  
Munetaka Masuda ◽  
Kunihiro Yonenaga ◽  
Toshihide Asou ◽  
Kouichi Tokunaga
Keyword(s):  
Coronary Sinus ◽  
Canine Heart ◽  
Retrograde Flow ◽  
Flow Through

Abstract W P106: A 3D Computational Model of the Hemodynamic Changes in EC-IC Bypass With Physiologic Boundary Conditions

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Mark Connolly ◽  
Fabien Scalzo ◽  
David S Liebeskind ◽  
Nestor R Gonzalez
Keyword(s):  
Boundary Conditions ◽  
Reconstruction Algorithm ◽  
Arterial Stenosis ◽  
Retrograde Flow ◽  
Severe Stenosis ◽  
Cerebrovascular Autoregulation ◽  
Ansys Simulation ◽  
Flow Through ◽  
Risk For Thrombosis ◽  
2D To 3D

Introduction: Intracranial arterial stenosis (IAS) accounts for 10% of ischemic strokes. EC-IC bypass trials have failed to show benefit of STA to MCA bypass over medical management, particularly for patients with severe stenosis rather than occlusion. These outcomes may be explained by retrograde flow from the bypass competing with flow through the stenosis, creating conditions at risk for thrombosis, such as stagnant or turbulent flow. We present a computational fluid dynamics model of EC-IC bypass extracted from patient images to demonstrate the hemodynamic effects of a bypass. Methods: A 2D-to-3D reconstruction algorithm was used to extract the vascular geometry from biplane angiograms of a patient with STA-MCA bypass. Additional details, such as the anterior temporal branch and lenticulostriates (LSAs) were added. The model was modified with varying degrees of stenosis. The boundary conditions of the outlets were adjusted to account for cerebrovascular autoregulation by finding the steady state of an autoregulatory model. The ANSYS: Simulation Technology package was used to evaluate hemodynamic parameters at 70% and 90% stenosis. Results: The 70% stenosis showed small pressure drop across the stenosis compared to the 90% stenosis (712Pa, 3618Pa). Flow velocity and wall shear stress (WSS) were substantially higher in the M1 segment distal to the lesion in the 70% stenosis model than in the 90% model (105cm/s, 27cm/s; 3.4Pa vs. 0.66Pa). Both models exhibited slow retrograde flow through the M2 segment (7cm/s, 10cm/s). Maximal turbulent kinetic energy (TKE) was higher in 70% stenosis model (0.00586m^2/s^2, 0.0012m^2/s^2). Conclusions: EC-IC bypass causes competitive flow within the M1 and M2 segments resulting in near complete stagnation of flow in regions of the MCA with high WSS and TKE, a set of conditions at high risk for intra-arterial thrombosis.

Intraventricular Fat from Retrograde Flow through a Lumboperitoneal Shunt

2010 ◽  
Vol 21 (3) ◽  
pp. 287-289 ◽  
Author(s):  
William Gallmann ◽  
Eduardo Gonzalez-Toledo ◽  
Rosario Riel-Romero
Keyword(s):  
Retrograde Flow ◽  
Lumboperitoneal Shunt ◽  
Flow Through

Disappearance of the shunt and lower cardiac index during exercise in small, unrepaired ventricular septal defects

2020 ◽  
Vol 30 (4) ◽  
pp. 526-532
Author(s):  
Marie Maagaard ◽  
Filip Eckerström ◽  
Johan Heiberg ◽  
Benjamin Asschenfeldt ◽  
Steffen Ringgaard ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Index ◽  
Pulmonary Artery ◽  
Exercise Capacity ◽  
Peak Exercise ◽  
Retrograde Flow ◽  
Ventricular Septal Defects ◽  
Septal Defects ◽  
Flow Through ◽  
Post Hoc

AbstractObjectives:Clinical studies have revealed decreased exercise capacity in adults with small, unrepaired ventricular septal defects. Increasing shunt ratio and growing incompetence of the aortic and pulmonary valve with retrograde flow during exercise have been proposed as reasons for the previously found reduced exercise parameters. With MRI, haemodynamic shunt properties were measured during exercise in ventricular septal defects.Methods:Patients with small, unrepaired ventricular septal defects and healthy peers were examined with MRI during exercise. Quantitative flow scans measured blood flow through ascending aorta and pulmonary artery. Scans were analysed post hoc where cardiac index, retrograde flows, and shunt ratio were determined.Results:In total, 32 patients (26 ± 6 years) and 28 controls (27 ± 5 years) were included. The shunt ratio was 1.2 ± 0.2 at rest and decreased to 1.0 ± 0.2 at peak exercise, p < 0.01. Aortic cardiac index was lower at peak exercise in patients (7.5 ± 2 L/minute/m2) compared with controls (9.0±2L l/minute/m2), p<0.01. Aortic and pulmonary retrograde flow was larger in patients during exercise, p < 0.01. Positive correlation was demonstrated between aortic cardiac index at peak exercise and previously established exercise capacity for all patients (r = 0.5, p < 0.01).Conclusions:Small, unrepaired ventricular septal defects revealed declining shunt ratio with increasing exercise and lower aortic cardiac index. Patients demonstrated larger retrograde flow both through the pulmonary artery and the aorta during exercise compared with controls. In conclusion, adults with unrepaired ventricular septal defects redistribute blood flow during exercise probably secondary to a more fixed pulmonary vascular resistance compared with age-matched peers.

Development of apical pits in chloride cells of the gills of Pimephales promelas after chronic exposure to acid water

1983 ◽  
Vol 41 ◽  
pp. 462-463
Author(s):  
Richard L. Leino ◽  
Jon G. Anderson ◽  
J. Howard McCormick
Keyword(s):  
Confidence Interval ◽  
Chronic Exposure ◽  
Lake Superior ◽  
Pimephales Promelas ◽  
Chloride Cells ◽  
Fathead Minnows ◽  
Secondary Lamellae ◽  
Untreated Water ◽  
Water Ph ◽  
Flow Through

Groups of 12 fathead minnows were exposed for 129 days to Lake Superior water acidified (pH 5.0, 5.5, 6.0 or 6.5) with reagent grade H2SO4 by means of a multichannel toxicant system for flow-through bioassays. Untreated water (pH 7.5) had the following properties: hardness 45.3 ± 0.3 (95% confidence interval) mg/1 as CaCO3; alkalinity 42.6 ± 0.2 mg/1; Cl- 0.03 meq/1; Na+ 0.05 meq/1; K+ 0.01 meq/1; Ca2+ 0.68 meq/1; Mg2+ 0.26 meq/1; dissolved O2 5.8 ± 0.3 mg/1; free CO2 3.2 ± 0.4 mg/1; T= 24.3 ± 0.1°C. The 1st, 2nd and 3rd gills were subsequently processed for LM (methacrylate), TEM and SEM respectively.Three changes involving chloride cells were correlated with increasing acidity: 1) the appearance of apical pits (figs. 2,5 as compared to figs. 1, 3,4) in chloride cells (about 22% of the chloride cells had pits at pH 5.0); 2) increases in their numbers and 3) increases in the % of these cells in the epithelium of the secondary lamellae.

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