What are the ultrasound features of an arteriovenous fistula (AVF)?
An AVF can occur anywhere in the body but most commonly occurs in the groin following arterial puncture of the femoral artery for a cardiac catheterization procedure or in the kidney following renal biopsy. Direct visualization of the fistula may be difficult, and therefore diagnosis typically relies on identifying color spectral Doppler changes to the arterial and venous waveforms proximal to the puncture site. Direct communication between an artery and vein results in a high-velocity, low-resistance (increased diastolic flow) waveform in the feeding artery and turbulent, pulsatile flow in the draining vein ( Figure 64-9 ). Color Doppler may also demonstrate perivascular vibration, due to turbulent blood flow, as a mix of random red and blue color in the soft tissues around the fistula site.