Arteriovenous (AV) fistula and graft surveillance uses duplex ultrasound to monitor hemodialysis access patency, detect early dysfunction, and identify lesions amenable to intervention before thrombosis. Systematic surveillance programs have been shown to reduce access loss and hospitalizations in dialysis patients.
Sonographers measure blood flow volume at the brachial artery (the feeding vessel), assess peak systolic velocities and velocity ratios across stenotic segments, and map the access anatomy from arterial anastomosis to central venous outflow. Flow volumes below 600 mL/min in fistulas or 800 mL/min in grafts suggest significant stenosis. Pseudoaneurysm, perigraft fluid, and steal syndrome are additional findings assessed during surveillance.
AV access surveillance falls under the ARDMS Vascular Technology (VT) specialty within the RVT credential. Sonographers in this subspecialty work in dialysis facilities, nephrology practices, and vascular access centers. As the dialysis patient population grows, AV access surveillance sonography represents a stable and growing area of employment in vascular ultrasound.