Renal AV fistula

Endovascular
intervention in renovascular disease: a pictorial review. Angiographic image of a right RAVF (a, black arrow) developed following ultrasound-guided biopsy of a transplant kidney with subsequent selective coil embolisation of arterial feeders (b, white arrow)
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Renal
arteriovenous fistula: Which US findings are expected?. Diagnostic catheter tip (white arrowhead) in the left renal artery. Note the presence of an arteriovenous fistula (red arrows) causing an early filling of the draining vein (blue arrows).
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Renal
arteriovenous fistula: Which US findings are expected?. Selective angiography of the lower pole segmental artery. White arrowhead: Diagnostic catheter. Yellow arrowhead: Micro-catheter in the segmental artery.
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Renal
arteriovenous fistula: Which US findings are expected?. After using coils (green arrow), blood keeps flowing through the arteriovenous fistula (red arrow).
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Renal
arteriovenous fistula: Which US findings are expected?. After using more coils (yellow arrow), blood flow could not be interrupted (red arrow).
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Renal
arteriovenous fistula: Which US findings are expected?. A non-adhesive liquid embolic agent (white arrows) was required to interrupt the blood flow within the fistula (red arrow).
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Renal
arteriovenous fistula: Which US findings are expected?. Core needle biopsy of the lower pole of the kidney. In this type of biopsy a hollow needle is used to remove tissue samples.
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Renal
arteriovenous fistula: Which US findings are expected?. In the lower pole of lthe eft kidney, a vascular area of aliasing is observed (red arrow). Note the presence of a segmental artery (orange arrow) and vein (blue arrow) heading towards this lesion.
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Renal
arteriovenous fistula: Which US findings are expected?. A feeding artery, probably an interlobar artery (orange arrows) conveys blood to the arteriovenous fistula. Note the aliasing artefact caused by a high-speed flow within the feeding artery as well as within the arteriovenous fistula.
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Renal
arteriovenous fistula: Which US findings are expected?. Orange arrow: Interlobar artery (feeding artery) Blue arrow: Interlobar vein (draining vein) Red arrows: Arteriovenous fistula (aliasing artefact)
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Renal
arteriovenous fistula: Which US findings are expected?. Draining interlobar and segmental vein (blue arrows).
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Renal
arteriovenous fistula: Which US findings are expected?. Lower pole segmental artery with a low resistive index. The feeding artery shows a high-velocity and low-resistance waveform. This is caused by a direct arteriovenous communication avoiding the capillary bed.
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Renal
arteriovenous fistula: Which US findings are expected?. The draining vein shows a pulsatile arterialized flow.
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Renal arteriovenous fistulae (AVFs) are anomalous direct communications between arteries and veins in the kidney, which may be confused with a renal arteriovenous malformation (rAVM).

Epidemiology

The incidence of renal AVF is variable, estimated at 0.3-19% in native kidneys and 6-8% in renal transplants . Approximately 70% of cases are acquired or iatrogenic, while about 20% are congenital .

Clinical presentation

The majority of renal AVFs are asymptomatic . However, it can present with flank pain, gross hematuria, acute urinary retention, hypertension, high output cardiac failure, renal insufficiency, massive hemorrhage or thromboembolic phenomena . At physical examination, continuous abdominal bruit or palpable thrill may be present.

Pathology

Renal arteriovenous fistulae are usually acquired lesions, unlike renal AVMs which are frequently developmental abnormalities. The majority of cases are iatrogenic and occur as a complication of renal biopsy, nephrostomy, blunt or penetrating trauma, inflammation, malignancy, or renal surgery .A few cases of congenital AVFs have been documented and are thought to be present at birth or to result from a congenital aneurysm that erodes into the adjacent vein .

Radiographic features

Renal arteriovenous fistulae may mimic renal AVMs on imaging. Renal AVFs should be suspected when a history of image guided percutaneous renal biopsy is present.

Ultrasound

Renal AVFs are usually imperceptible in B-mode.

Color Doppler images depict a flash of color, “visible thrill” or “soft tissue bruit”, that results from the vibration of the soft tissue surrounding the renal AVF, producing a focal color mosaic overlying the adjacent soft tissue . Adjusting the color Doppler to higher velocities may show the feeding artery and the enlarged draining vein.

Spectral Doppler tracings show a high-velocity, low resistance flow within the artery and turbulent, pulsatile, arterialized flow in the segmental draining vein. If large, the main renal vein may have pulsatile flow.

CT

CT angiography may demonstrate the anomalous renal arteriovenous communication with associated aneurysms and early opacification of the renal vein on the arterial phase .

Treatment and prognosis

Renal AVFs usually resolve spontaneously. It may be treated whenever it is symptomatic, large or extrarenal . The therapeutic method of choice is endovascular intervention. Different technical methods of embolization are available . Surgical treatment is partial or total nephrectomy or arterial ligation .

Siehe auch:
Assoziationen und Differentialdiagnosen zu arteriovenöse Fistel der Niere:
Embolisationen
Arteria renalis und Niere
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Embolisation
arteriovenöse Fistel der Niere
insightsimaging.springeropen.com • Open Access
Arteriovenöse
Fistel
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