Stenosis in a vascular access circuit is the predominant cause of
access dysfunction. Hemodynamic significance of a stenosis identified by
angiography in an access circuit is uncertain. This study utilizes
computational fluid dynamics (CFD) to model flow through arteriovenous
fistula to predict the functional significance of stenosis in vascular
access circuits.
Methods
Three-dimensional models of fistulas were created with a range of
clinically relevant stenoses using SolidWorks. Stenoses diameters ranged
from 1.0 to 3.0 mm and lengths from 5 to 60 mm within a fistula diameter
of 7 mm. CFD analyses were performed using a blood model over a range of
blood pressures. Eight patient-specific stenoses were also modeled and
analyzed with CFD and the resulting blood flow calculations were
validated by comparison with brachial artery flow measured by duplex
ultrasound.
Results
Predicted flow rates were derived from CFD analysis of a range of
stenoses. These stenoses were modeled by CFD and correlated with the
ultrasound measured flow rate through the fistula of eight patients. The
calculated flow rate using CFD correlated within 20% of ultrasound
measured flow for five of eight patients. The mean difference was 17.2%
(ranged from 1.3% to 30.1%).
Conclusions
CFD analysis-generated flow rate tables provide valuable information
to assess the functional significance of stenosis detected during
imaging studies. The CFD study can help in determining the clinical
relevance of a stenosis in access dysfunction and guide the need for
intervention.
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