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Retroperitoneum » Kidneys, Ureters
Arteriovenous Fistula in a Renal Transplant
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Author(s) :
Danilo Sirigu, MD
 
Presentation

A 41 year-old male patient with a renal transplant is referred for ultrasound exam.  The patient had a renal biopsy 2 weeks prior to the exam and now presents with elevated levels of serum creatinine.

 
 
 
Caption: Color Doppler Image 1
Description: Color Doppler identifies a .5 cm area of color mosaic, typical of chaotic high-velocity flow.
 
 
 
Caption: Color Doppler Image 2
Description: A slightly different plane further demonstrates typical aliasing and chaotic flow.
 
 
 
Caption: Color/Spectral Doppler Image 3
Description: Spectral Doppler demonstrates a high velocity low resistance flow pattern with spectral broadening.
 
 
Caption: Video 1
Description: Ultrasound examination of the kidney shows a subtle urothelial thickening, and mild prominence of the collecting system.
 
 
Caption: Video 2
Description: Color Doppler ultrasonography shows an abnormal focus of increased flow in the upper pole of the transplanted kidney with afferent and efferent vessels.
 
 
Caption: Video 3
Description: Spectral Doppler tracing showed a turbulent, high-velocity arterial waveform. The findings were correlated with the presence of an arteriovenous fistula.
 
Final Diagnosis

Intrarenal Arteriovenous Fistula

 
Discussion

Intrarenal arteriovenous fistula occurs as a consequence of simultaneous laceration of a renal artery branch and an adjacent vein during biopsy.

The majority of these lesions are small, are clinically insignificant, and usually resolve spontaneously; thus, the frequency of this complication is unknown. When lesions are sizable, marked arteriovenous shunting may result in renal ischemia. When symptomatic or large, intrarenal arteriovenous fistulas may be effectively treated with embolization .

At US an anomalous ectatic intrarenal vascular structure may be seen but color Doppler immediately identifies the lesion as vascular.  If color Doppler gain is steadily reduced to the point where normal renal blood flow disappears, the lesion will remain like a flashing beacon.

On colour flow Doppler analysis the fistula appears as a mosaic, a focal irregular combination of colors with aliasing due to high speed and turbulence of the flow.

 
Case References

Brown ED, Chen MY, Wolfman NT, Ott DJ, Watson NE Jr. Complication of renal transplantation: evaluation with US and radionuclide imaging. Radiographics 2000; 20:607–622

Akbar SA, Jafri SZ, Amendola MA, Madrazo BL, Salem R, Bis KG. Complication of renal transplantation. Radiographics 2005; 25:1335–1356.

Boschiero LB, Saggin P, Galante O, et al. Renal needle biopsy of the transplant kidney: vascular and urologic complications. Urol Int 1992; 48:130–133

Urogenital Ultrasound: A Text Atlas. Cochlin DL, Dubbins PA, Goldberg BB. Jan 1, 1994

 
Technical Details

A special thanks to Dr. Danilo Sirigu who generously contributed this case from his outstanding web site www.ecomovies.it
Please visit http://www.ecomovies.it  to access a wide range of very high quality video cases.