VALIDATION IN SHEEP OF THE ULTRASOUND DILUTION TECHNIQUE FOR HEMODIALYSIS GRAFT FLOW

Arterio-Venous (AV) grafts which are used for hemodialysis, frequently develop intimal hyperplasia (IH) in venous anastomosis and ultimately leads to graft failure which is the major cause of morbidity and mortality in patients with the end stage renal disease (ESRD). Although the high AV access blood flow has been implicated in the pathogenesis of graft stenosis, the potential role of needle turbulence during hemodialysis is relatively unexplored. In the current study, a numerical survey is carried out to investigate the effect of venous needle's flow on hemodynamic parameters of the flow inside a hemodialysis graft. Two cases include the individual graft flow and the graft flow combined with a needle flow which both of them are evaluated and their results are compared to the cell morphology are represented in this research. Blood is considered as an incompressible Newtonian fluid with density of 1050 [Kg/(m3)] and dynamic viscosity of 0.0035 [Pa.s] and the graft was considered as a rigid vessel due to its low compliance. Flow rates were considered 500 and 100 [mL/min] as inlet conditions of the graft and the needle, respectively. Results show that the presence of the needle's flow causes to increase the amount of shear stress and nonuniformity of the shear stress distribution on the graft wall, where the cell alignment is lost in the presence of needle flow. These findings suggest the presence of potential relationship between venous needle flow during hemodialysis and endothelial dysfunction which may lead to vascular injury and graft failure.

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Comparison of Transpulmonary Thermodilution and Ultrasound Dilution Technique: Novel Insights into Volumetric Parameters from an Animal Model

Pediatric Cardiology ◽

10.1007/s00246-012-0192-0 ◽

2012 ◽

Vol 33 (4) ◽

pp. 625-632 ◽

Cited By ~ 7

Author(s):

Martin Boehne ◽

Florian Schmidt ◽

Lars Witt ◽

Harald Köditz ◽

Michael Sasse ◽

...

Keyword(s):

Animal Model ◽

Transpulmonary Thermodilution ◽

Dilution Technique ◽

Ultrasound Dilution

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Determination of Cardiac Output by Ultrasound Dilution Technique in Infants and Children: A Validation Study against Direct Fick Principle

The Thoracic and Cardiovascular Surgeon ◽

10.1055/s-0033-1354429 ◽

2013 ◽

Vol 61 (S 02) ◽

Author(s):

M Boehne ◽

M Baustert ◽

V Paetzel ◽

H Köditz ◽

S Schoof ◽

...

Keyword(s):

Cardiac Output ◽

Validation Study ◽

Infants And Children ◽

Dilution Technique ◽

Ultrasound Dilution ◽

Fick Principle ◽

In Infants And Children

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Screening for hemodialysis graft stenosis and short-term thrombosis risk: A comparison of the available tools

The Journal of Vascular Access ◽

10.1177/1129729819867552 ◽

2019 ◽

Vol 21 (2) ◽

pp. 195-203 ◽

Cited By ~ 1

Author(s):

Nicola Tessitore ◽

Giovanni Lipari ◽

Alberto Contro ◽

Francesca Moretti ◽

Giancarlo Mansueto ◽

...

Keyword(s):

Blood Flow ◽

Relative Risk ◽

Confidence Interval ◽

Short Term ◽

Ultrasound Dilution ◽

Graft Stenosis ◽

Thrombosis Risk ◽

Increased Risk ◽

Acute Hypotension ◽

Hemodialysis Graft

Introduction: Guidelines recommend hemodialysis graft screening to identify and repair significant (>50%) stenosis at high risk of thrombosis, but there is insufficient evidence to prefer one or other screening tool due to the lack of studies comparing all available options. Methods: Seeking an optimal screening approach, we compared the performance of all currently used tools (duplex ultrasound to detect significant stenosis (StD) and measure access blood flow (QaD), ultrasound dilution access blood flow (QaU), static venous intra-access pressure ratio (VAPR), dynamic arterial and venous pressures measurement, and monitoring) for diagnosing significant angiography-proven stenosis (StA) and predicting incipient thrombosis (occurring within 4 months) in 62 grafts. All thrombotic and symptomatic acute hypotension episodes were recorded during follow-up. Results: VAPR > 0.70 and QaU < 1600 mL/min were the best indicators to angiography for those aiming to identify the majority of StA (91% sensitivity) and QaU < 1000 mL/min or StD for those aiming to avoid unnecessary angiograms (95%–93% positive predictive value). At Cox’s analysis, the only significant thrombosis predictors were acute hypotension episodes (relative risk = 4.4 (95% confidence interval = 2.2–8.8), p < 0.0001) and QaU or QaD (14% (95% confidence interval = 8–21) or 16% (95% confidence interval = 6–25) increased risk per 100 mL/min drop in Qa, p < 0.003). Thrombosis risk (adjusted for acute hypotension) became significantly higher at QaU = 1000–700 mL/min (relative risk = 3.6 (95% confidence interval = 1.6–8.2), p < 0.001) and QaD = 1300–1000 mL/min (relative risk = 3.1 (95% confidence interval = 1.1–12.8), p = 0.031). The proportion of thromboses attributable to acute hypotension was 40% (95% confidence interval = 24–57). Conclusions: Our comparative study showed that an effective screening for graft stenosis and short-term thrombosis risk can rely on Qa surveillance alone, and suggested that avoiding acute hypotension and correcting stenosis at QaU < 1000 mL/min or QaD < 1300 mL/min can contain thrombosis risk.

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