ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology

2021 ◽  
pp. 112972982110335
Author(s):  
Gerald A Beathard ◽  
William C Jennings ◽  
Haimanot Wasse ◽  
Surendra Shenoy ◽  
Abigail Falk ◽  
...  
Keyword(s):  
Blood Flow ◽  
Neointimal Hyperplasia ◽  
Primary Treatment ◽  
White Paper ◽  
Complete Characterization ◽  
Intraluminal Pressure ◽  
Luminal Diameter ◽  
Stenotic Lesion ◽  
Venous Stenosis ◽  
Increased Blood Flow

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

scholarly journals Increased blood flow inhibits neointimal hyperplasia in endothelialized vascular grafts.

1991 ◽  
Vol 69 (6) ◽  
pp. 1557-1565 ◽  
Author(s):  
T R Kohler ◽  
T R Kirkman ◽  
L W Kraiss ◽  
B K Zierler ◽  
A W Clowes
Keyword(s):  
Blood Flow ◽  
Neointimal Hyperplasia ◽  
Vascular Grafts ◽  
Increased Blood Flow

Exploring correlations between anatomic characteristics of dialysis arteriovenous fistula stenosis and arteriovenous fistula blood flow rate (Qa)

2019 ◽  
Vol 21 (1) ◽  
pp. 60-65
Author(s):  
George M Nassar ◽  
Gerald Beathard
Keyword(s):  
Blood Flow ◽  
Arteriovenous Fistula ◽  
Flow Rate ◽  
Blood Flow Rate ◽  
Operating Characteristics ◽  
Weak Correlation ◽  
Luminal Diameter ◽  
Stenotic Lesion ◽  
Receiver Operating Characteristics Curve ◽  
Arteriovenous Fistula Stenosis

Background: Radiologic justification for endovascular treatment of a dialysis arteriovenous fistula circuit stenosis is currently based on ⩾50% severity. However, the clinical significance of any given stenosis is not always clear. The minimum luminal diameter of any stenotic lesion in the arteriovenous fistula circuit might exert a more predictive effect on the arteriovenous fistula blood flow rate (Qa). Methods: To investigate relationships between anatomic parameters of stenosis and Qa, this study was conducted in a cohort of patients with a variety of arteriovenous fistula stenotic lesions. The goals were to determine (1) the degree of correlation between arteriovenous fistula stenosis estimated during the procedure, and that which is measured, and (2) the correlations between two anatomic stenosis parameters (percent stenosis and stenosis minimum luminal diameter) and Qa. Results: The cohort comprised 113 patients. Only a moderate correlation between estimated and measured stenosis was seen. A correlation between measured stenosis and Qa for the whole cohort was not seen, but a weak correlation between estimated stenosis and Qa was seen. Correlations between stenosis minimum luminal diameter and Qa were superior. The superiority of stenosis minimum luminal diameter to percent stenosis in correlating with a Qa of <500 mL/h was also demonstrated by receiver operating characteristics curve analysis. Stenosis minimum luminal diameter cutoffs of ⩽2.5 mm or >4 mm seemed to have a good predictive value of Qa. Conclusions: Percent stenosis determination is fraught with uncertainty and exhibits a weak correlation with Qa. Compared with percent stenosis, the minimum luminal diameter of the stenosis demonstrates a superior correlation with Qa.

Diastolic pressure and peripheral resistance during stellate ganglion stimulation

1963 ◽  
Vol 204 (1) ◽  
pp. 71-72 ◽  
Author(s):  
Edward D. Freis ◽  
Jay N. Cohn ◽  
Thomas E. Liptak ◽  
Aristide G. B. Kovach
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Total Peripheral Resistance ◽  
Diastolic Pressure ◽  
Stellate Ganglion ◽  
Peripheral Resistance ◽  
Resistance Vessels ◽  
Left Stellate Ganglion ◽  
Increased Blood Flow

The mechanism of the diastolic pressure elevation occurring during left stellate ganglion stimulation was investigated. The cardiac output rose considerably, the heart rate remained essentially unchanged, and the total peripheral resistance fell moderately. The diastolic rise appeared to be due to increased blood flow rather than to any active changes in resistance vessels.

scholarly journals Diagnosis of Fibrotic Distal Ileum Stenosis after Ischemic Enteritis Using Transabdominal Ultrasonography

2021 ◽  
pp. 568-577
Author(s):  
Ryo Katsumata ◽  
Noriaki Manabe ◽  
Masaki Matsubara ◽  
Jun Nakamura ◽  
Kazuma Kawahito ◽  
...  
Keyword(s):  
Blood Flow ◽  
Case Reports ◽  
Blood Perfusion ◽  
Distal Ileum ◽  
Wall Thickening ◽  
Current Case ◽  
Abdominal Ultrasonography ◽  
Transabdominal Ultrasonography ◽  
Stenotic Lesion ◽  
Ischemic Enteritis

Ischemic enteritis (IE) is a rare disorder which is caused by inadequate blood flow to small intestine. The diagnostic procedure of this disease has not sufficiently established because of its rarity. Here, we report a case of IE in a hemodialysis-dependent 70-year-old man and summarize the diagnostic options for IE. The patient was admitted to our hospital because of acute abdominal distention and vomiting. He presented with mild tenderness in the lower abdomen and slightly elevated C-reactive protein level as revealed by blood tests. Radiographic imaging showed small bowel obstruction due to a stricture in the distal ileum. Contrast-enhanced abdominal ultrasonography revealed a 7-cm stenotic site with increased intestinal wall thickening, which preserved mucosal blood perfusion. Elastography revealed a highly elastic alteration of the stenotic lesion, indicating benign fibrotic changes resulting from chronic insufficient blood flow. Based on a clinical diagnosis of IE with fibrous stenosis, a partial ileostomy was performed. After surgical treatment, oral intake was initiated without recurrence of intestinal obstruction. Pathological findings revealed deep ulceration with inflammatory cell infiltration at the stenotic site. Occlusion and hyalinization of the venules in the submucosal layer indicated IE. In addition to current case, we reviewed past case reports of IE. Through this case presentation and literature review, we summarize the usefulness and safety of transabdominal ultrasonography for diagnosing IE.

Collapse of Arteries Subjected to an External Band of Pressure

1980 ◽  
Vol 102 (1) ◽  
pp. 8-22 ◽  
Author(s):  
A. M. Hecht ◽  
H. Yeh ◽  
S. M. K. Chung
Keyword(s):  
Reynolds Number ◽  
Blood Flow ◽  
Cylindrical Shell ◽  
Orthotropic Cylindrical Shell ◽  
Reynolds Numbers ◽  
Intraluminal Pressure ◽  
Collapse Pressure ◽  
Vessel Size ◽  
Flow Reynolds Number ◽  
Small Band

Collapse of arteries subjected to a band of hydrostatic pressure of finite length is analyzed. The vessel is treated as a long, thin, linearly elastic, orthotropic cylindrical shell, homogeneous in composition, and with negligible radial stresses. Blood in the vessel is treated as a Newtonian fluid and the Reynolds number is of order 1. Results are obtained for effects of the following factors on arterial collapse: intraluminal pressure, length of the pressure band, elastic properties of the vessel, initial stress both longitudinally and circumferentially, blood flow Reynolds number, compressibility, and wall thickness to radius ratio. It is found that the predominant parameter influencing vessel collapse for the intermediate range of vessel size and blood flow Reynolds numbers studied is the preconstricted intraluminal pressure. For pressure bands less than about 10 vessel radii the collapse pressure increases sharply with increasing intraluminal pressure. Initial axial prestress is found to be highly stabilizing for small band lengths. The effects of fluid flow are found to be small for pressure bands of less than 100 vessel radii. No dramatic orthotropic vessel behavior is apparent. The analysis shows that any reduction in intraluminal pressure, such as that produced by an upstream obstruction, will significantly lower the required collapse pressure. Medical implications of this analysis to Legg-Perthes disease are discussed.

Increased blood flow to lower limbs after plasma exchange in two patients with familial hypercholesterolemia

1982 ◽  
Vol 41 (2-3) ◽  
pp. 421-425 ◽  
Author(s):  
A. Postiglione ◽  
P. Rubba ◽  
N. Scarpato ◽  
A. Iannuzzi ◽  
M. Mancini
Keyword(s):  
Blood Flow ◽  
Plasma Exchange ◽  
Familial Hypercholesterolemia ◽  
Lower Limbs ◽  
Increased Blood Flow

In vivo microvascular structural and functional consequences of muscle length changes

1997 ◽  
Vol 272 (5) ◽  
pp. H2107-H2114 ◽  
Author(s):  
D. C. Poole ◽  
T. I. Musch ◽  
C. A. Kindig
Keyword(s):  
Blood Flow ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Oxygen Delivery ◽  
Sarcomere Length ◽  
Flow Dynamics ◽  
Capillary Diameter ◽  
Luminal Diameter ◽  
Length Changes

As muscles are stretched, blood flow and oxygen delivery are compromised, and consequently muscle function is impaired. We tested the hypothesis that the structural microvascular sequellae associated with muscle extension in vivo would impair capillary red blood cell hemodynamics. We developed an intravital spinotrapezius preparation that facilitated direct on-line measurement and alteration of sarcomere length simultaneously with determination of capillary geometry and red blood cell flow dynamics. The range of spinotrapezius sarcomere lengths achievable in vivo was 2.17 +/- 0.05 to 3.13 +/- 0.11 microns. Capillary tortuosity decreased systematically with increases of sarcomere length up to 2.6 microns, at which point most capillaries appeared to be highly oriented along the fiber longitudinal axis. Further increases in sarcomere length above this value reduced mean capillary diameter from 5.61 +/- 0.03 microns at 2.4-2.6 microns sarcomere length to 4.12 +/- 0.05 microns at 3.2-3.4 microns sarcomere length. Over the range of physiological sarcomere lengths, bulk blood flow (radioactive microspheres) decreased approximately 40% from 24.3 +/- 7.5 to 14.5 +/- 4.6 ml.100 g-1.min-1. The proportion of continuously perfused capillaries, i.e., those with continuous flow throughout the 60-s observation period, decreased from 95.9 +/- 0.6% at the shortest sarcomere lengths to 56.5 +/- 0.7% at the longest sarcomere lengths and was correlated significantly with the reduced capillary diameter (r = 0.711, P < 0.01; n = 18). We conclude that alterations in capillary geometry and luminal diameter consequent to increased muscle sarcomere length are associated with a reduction in mean capillary red blood cell velocity and a greater proportion of capillaries in which red blood cell flow is stopped or intermittent. Thus not only does muscle stretching reduce bulk blood (and oxygen) delivery, it also alters capillary red blood cell flow dynamics, which may further impair blood-tissue oxygen exchange.

Vascular responses of dura mater

1989 ◽  
Vol 257 (1) ◽  
pp. H157-H161 ◽  
Author(s):  
F. M. Faraci ◽  
K. A. Kadel ◽  
D. D. Heistad
Keyword(s):  
Blood Flow ◽  
Substance P ◽  
Dura Mater ◽  
Sympathetic Nerves ◽  
Vascular Headache ◽  
Vascular Responses ◽  
Anesthetized Dogs ◽  
High Level ◽  
The Brain ◽  
Increased Blood Flow

The goal of this study was to examine vascular responses of the dura mater. Microspheres were used to measure blood flow to the dura and brain in anesthetized dogs. Under control conditions, blood flow to the dura was 38 +/- 3 (SE) ml.min-1.100 g-1. Values for blood flow to the dura obtained with simultaneous injection of 15- and 50-microns microspheres were similar, which suggests that shunting of 15-microns spheres was minimal. Left atrial infusion of substance P (100 ng.kg-1.min-1) and serotonin (40 micrograms.kg-1.min-1), two agonists that have been reported to increase vascular permeability in the dura, increased blood flow to the dura two- to threefold. Adenosine (iv) produced vasodilatation in the dura. Adenosine and serotonin did not affect cerebral blood flow, but substance P increased blood flow to the brain by approximately 40%. Seizures, which produce pronounced dilatation of cerebral vessels despite activation of sympathetic nerves, produced vasoconstriction in the dura. Thus 1) the dura is perfused at a relatively high level of blood flow under normal conditions and is very responsive to vasoactive stimuli, and 2) substance P and serotonin, which have been implicated in the pathogenesis of vascular headache, produce pronounced vasodilator responses in the dura mater.

Substrate utilization in leg muscle of men after heat acclimation

1987 ◽  
Vol 63 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J. P. Kirwan ◽  
D. L. Costill ◽  
H. Kuipers ◽  
M. J. Burrell ◽  
W. J. Fink ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Glycogen ◽  
Respiratory Exchange Ratio ◽  
Plasma Free Fatty Acid ◽  
Heat Acclimation ◽  
Substrate Utilization ◽  
Acclimation Period ◽  
Glycogen Utilization ◽  
Leg Muscle ◽  
Increased Blood Flow

Eight men were heat acclimated (39.6 degrees C and 29.2% rh) for 8 days to examine changes in substrate utilization. A heat exercise test (HET), (cycling for 60 min; 50% maximal O2 consumption) was performed before (UN-HET) and after (ACC-HET) the acclimation period. Muscle glycogen utilization (67.0 vs. 37.6 mmol/kg wet wt), respiratory exchange ratio (0.85 +/- 0.002 vs. 0.83 +/- 0.001), and calculated rate of carbohydrate oxidation (75.15 +/- 1.38 vs. 64.80 +/- 1.52 g/h) were significantly reduced (P less than 0.05) during the ACC-HET. Significantly lower (P less than 0.05) femoral venous glucose (15, 30, and 45 min) and lactate (15 min) levels were observed during the ACC-HET. No differences were observed in plasma free fatty acid (FFA) and glycerol concentrations or glucose, lactate and glycerol arteriovenous uptake/release between tests. A small but significant increase (P less than 0.05) above resting levels in FFA uptake was observed during the ACC-HET. Leg blood flow was slightly greater (P greater than 0.05) during the ACC-HET (4.64 +/- 0.13 vs. 4.80 +/- 0.13 l/min). These findings indicate a reduced use of muscle glycogen following heat acclimation. However, the decrease is not completely explained by a shift toward greater lipid oxidation or increased blood flow.

scholarly journals The Efficiency of Synthetic Sex Pheromones in Sexual Arousal Stimulation in Domestic Dogs

2017 ◽  
Vol 20 (3) ◽  
pp. 429-437 ◽  
Author(s):  
M. Dzięcioł ◽  
W. Niżański ◽  
T. Jezierski ◽  
A. Szumny ◽  
E.J. Godzińska ◽  
...  
Keyword(s):  
Blood Flow ◽  
Sexual Arousal ◽  
Adult Male ◽  
Sex Pheromones ◽  
Domestic Dogs ◽  
Behavioral Arousal ◽  
Sexual Stimulation ◽  
Penile Artery ◽  
Increased Blood Flow ◽  
Stimulation Of

Abstract The aim of this study was to evaluate the suitability of synthetic bitch sex pheromones (Eau’ De Estrus®, Synbiotics USA) for the stimulation of the reproductive reflexes in adult male dogs. In experiment I: anoestral bitches were applied synthetic (n=6) or natural (n=6) pheromones and their attractiveness was compared to the attractiveness of bitches in natural oestrus, In experiment II: swabs socked in natural estrual discharge or Eau D’Estrus were presented to male dogs and behavioral arousal (Exp. II a) and changes in blood flow in the penile artery reflecting erection (Exp. II b) were recorded. In experiment III the time dedicated for sniffing in experimental dogs was analyzed in relation to the type of attractant presented (natural estrual discharge or Eau D’Estrus). In all three experiments we observed the signs of sexual arousal, increased blood flow in the penile artery and increased time of sniffing only with natural pheromones. No signs of excitation or changes in penis perfusion were noted after the use of artificial pheromones. Our results did not support the suitability of Eau D’Estrus for male dog sexual stimulation.

Sign in / Sign up

Export Citation Format

Share Document