Prepared by Charles Ariz, MD; Jade Wong-You Cheong, MD; and Geoffrey Hastings, MD, Department of Radiology, University of Maryland, Baltimore, MD.

CASE SUMMARY:

A 53-year-old woman presented with hematuria and elevated creatinine after a percutaneous biopsy of her renal transplant. Sonography with Doppler was performed (figures 1A, 1B). This was followed by arteriography (figures 2A, 2B) and intervention (figure 2C). What is the most likely diagnosis?

ANSWER: Post-biopsy arteriovenous fistula (AVF) in a renal transplant

DISCUSSION:

It is not uncommon for traumatic arteriovenous fistulae to develop after percutaneous biopsy of renal transplants. As a result of the cutting needle, a direct communication is formed between an intrarenal artery and vein. Patients are most commonly asymptomatic but may present with new onset hematuria, pain, or elevation in creatinine. Most small AVFs resolve spontaneously without intervention. Less commonly, AVF may cause renal hypertension or high output cardiac failure.

Gray-scale sonography typically demonstrates no abnormalities. Color and duplex Doppler are invaluable in making this diagnosis, demonstrating a characteristic pattern of findings. Increased arterial diastolic velocities occur as a result of the abnormal arteriovenous communication and the low resistance to arterial flow. Increased velocities are also observed within the draining vein, as is a pulsatile waveform resulting in an arterialized appearance. Localized turbulent venous flow often is present at the site of the AVF, causing vibration of the perivascular soft tissue. This causes random assignment of color Doppler in the soft tissue in the immediate vicinity of the AVF, known as a perivascular bruit or thrill.

Selective renal arteriography is effective in demonstrating direct AV communication within the post-biopsy renal allograft. Most asymptomatic patients are managed conservatively, and the majority of these patients will have AVFs that close spontaneously. When patients are symptomatic, super-selective embolization, done as part of the arteriography procedure, is the preferred treatment option and enjoys a high rate of success. A variety of embolization materials have been employed, including micro-coils and gelfoam, as used in this case. The goal of treatment is permanent cessation of flow within the AVF with minimal sacrifice of renal parenchyma.

References

1. Castaneda-Zuniga WR, Tadavarthy SM, Young AT, et al: Interventional Radiology, vol 1, pp 45-46. Baltimore, Williams & Wilkins, 1992.

2. Kurtz AB, Middleton WD: Ultrasound: The Requisites, pp 482-483. St Louis, Mosby, 1995.

3. Matsell DG, Jones DP, Boulden TF, et al: Arteriovenous fistula after biopsy of renal transplant kidney: Diagnosis and treatment. Pediatr Nephrol 6:562-564, 1992.

4. Middleton WD, Kellman GM, Melson GL, Madrazo BL: Postbiopsy renal transplant arteriovenous fistulas: Color Doppler and US characteristics. Radiology 171:253-257, 1989.