Fact-sheet: Renal arteriovenous fistula


Updated on 09/06/2023 at 5:10 PM

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Definition

Abnormal direct communication between the arterial and venous networks of the kidney.

Acquired origin in most cases (iatrogenic++, post-biopsy, dialysis fistula, nephrostomy, kidney surgery, trauma to kidney) or congenital.

Incidence:

  • 0.3-19% for native kidneys
  • 6-8% for renal transplants

In the context of post-biopsy renal transplant: corresponds to a vascular complication that may be early or late (look for an associated pseudoaneurysm).

Clinical features

Generally asymptomatic.

If symptomatic:

  • gross hematuria
  • abdominal pain
  • acute urinary retention
  • hypertension
  • Renal failure
  • Hemorrhage

Ultrasound

First-line examination, especially in the setting of a renal transplant.

B-mode: most often without evident abnormality; occasionally a small hyperechoic "vascular sac" focus may be visible.

Doppler mode:

  • Perivascular "aliasing" artifact = heterogeneous, focal color mosaic that pulses in systole and decreases in diastole (pulsatile aliasing pattern).
  • Focal turbulence = spectral broadening with increased velocities at the AVF (low-resistance flow in the feeding artery with RI <0.5, and "arterialized," turbulent draining venous flow).

Management

Generally resolves spontaneously.

Treatment considered if the AVF is large or symptomatic:

  • endovascular ++
  • surgical

Differential diagnosis

In the setting of a renal transplant, look for causes of graft dysfunction:

  • other vascular complications: pseudoaneurysm ++, venous thrombosis, occlusion and stenosis of the pedicular/polar artery.
  • urologic complications: pyelonephritis/abscess, obstruction (hematoma, ureteral anastomotic stenosis, lymphocele), cancer/lymphoma, urinary fistula.
  • parenchymal complications: hyperacute/acute/chronic rejection, ATN, drug-induced nephrotoxicity, recurrence of the underlying disease.