Color Duplex Ultrasound in Dialysis Access Surveillance

Abstract

Failure of dialysis access maturation or dysfunction during chronic hemodialysis cannulation is a common clinical problem in the end-stage renal disease patient. Duplex ultrasound imaging with volume flow estimation is the recommended diagnostic technique to identify anatomic conditions preventing access maturation, conduit injury caused by cannulation, low access volume flow, or conduit aneurysmal degeneration. The hemodynamic consequence of a duplex-identified access stenosis on volume flow or digit ischemia due to access-associated steal can be determined based on the proximal and distal brachial artery pulsed-Doppler arterial waveforms and flow velocity. Dialysis access maturation can be predicted by imaging of conduit for diameter and depth and the flow hemodynamics of the inflow artery and/or access conduit. Access volume flow can be estimated based on measurements of the inflow artery systolic and end-diastolic flow velocities which allows classification into three ranges: low (<600 ml/min), moderate (600–800 ml/min), and high (>800 ml/min). An access flow of >800 mL/min predicts successful hemodialysis when the access conduit has appropriate diameter (≥6 mm) and depth (<6 mm) for cannulation. When access flow is low (<600 ml/min), indicating maturation failure or dysfunction, the presence of a duplex-identified access stenosis can guide the decision for access revision. The routine application of color duplex ultrasound surveillance after autogenous vein or prosthetic bridge graft dialysis access procedures is recommended to predict access maturation and identify conditions impairing access function in the renal failure patient whose life is dependent on chronic hemodialysis.