Static intra-access pressure ratio does not correlate with access blood flow

Spergel, Lawrence M.; Holland, Janet; Fadem, Stephen Z.; McAllister, Charles J.; Peacock, E

doi:10.1111/j.1523-1755.2004.00946.x

Cited by 31 publications

(28 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As further confirmation, we can compare the model with clinical data on the relation between VP/MAP and Q ( Figure 9) (22). The scatter in Figure 9 is wider than that in Figure 8, but this difference is easily explained.…”

Section: Discussionmentioning

confidence: 71%

“…Besarab et al (20,33) found that a high VP/MAP is associated with low Q, whereas Spergel et al (22) found no correlation between VP/MAP and Q (Figure 9). Thus, we used the model to examine the relation between these variables.…”

Section: Discussionmentioning

confidence: 91%

“…The influence of diameters on VP/MAP is explained by showing how relative upstream and downstream resistances affect VP/MAP (22). VP/MAP can be approximated by equation 2 in the Materials and Methods section:…”

Section: Discussionmentioning

confidence: 99%

“…The effect of luminal diameters on VP/MAP is understood by deriving the relation between VP/MAP and vascular resistance (22). Q is determined by the following equation: Q ϭ (MAP Ϫ CVP)/(R IN ϩ R OUT ).…”

Section: Relation Between Vp/map and Resistancementioning

confidence: 99%

“…However, some have found that VP surveillance predicts stenosis or thrombosis (19,20), and some have not (21). Also, a recent study (22) found no correlation between Q and VP/MAP. It suggested that artery and vein diameters may vary between patients and thereby affect VP by altering resistances in the graft circuit.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Mathematical Model Demonstrates Influence of Luminal Diameters on Venous Pressure Surveillance

White

Jones

Ram

et al. 2007

Clinical Journal of the American Society of Nephrology

View full text Add to dashboard Cite

Background: The reliability of dialysis venous pressure (VP) in detecting stenosis is controversial. A mathematical model may help to resolve the controversy by providing insight into the factors that influence static VP.Design, setting, participants, and measurements: This study used inflow artery and outflow vein luminal diameters from duplex ultrasound studies of 94 patients. These diameters were applied to a mathematical model, and how they affect the relation among VP, mean arterial pressure (MAP), blood flow, and stenosis was determined. Whether VP/MAP is a valid adjustment for the influence of MAP on VP, and whether the standard VP/MAP referral threshold of 0.50 is valid, were also determined.Results: It was found that there is an approximate one-to-one relation between MAP and VP, so VP/MAP is a valid adjustment. Also, the 0.50 threshold successfully identifies most grafts with stenosis of 65% or more. However, the ratio of artery/vein diameters varied widely between patients, and the ratio independently influences VP/MAP. When the inflow artery is relatively narrow, the VP/MAP increase is delayed followed by a more rapid increase as critical stenosis is reached.Conclusions: VP/MAP is a valid adjustment for the influence of MAP on VP, and the standard VP/MAP threshold of 0.50 warns of the transition to critical stenosis. However, relatively narrow arteries cause a delay followed by a rapid increase in VP/MAP that may not be detected before thrombosis unless measurements are very frequent. Clinical trials that emphasize trend analysis with frequent measurements are needed to evaluate the efficacy of VP surveillance.

show abstract

Section: Discussionmentioning

confidence: 71%