Aorto-left renal vein fistula
Aorto-left renal vein fistula is an extremely rare complication of abdominal aortic aneurysm rupture. The initial clinical presentation is often non-specific, however, characteristic imaging findings, if recognised early, can lead to prompt diagnosis and assist in surgical planning.
Spontaneous aorto-left renal vein fistula most commonly involved a variant retroaortic left renal vein and less commonly seen in trauma or post-surgical complications.
Clinical presentation is often non-specific, which includes abdominal, left flank and groin pain. It can mimic gastrointestinal and urologic conditions. Specific clinical findings include palpable pulsatile aorta or bruits on auscultation. Haematuria is often a presenting feature and most often the patient has an abnormal renal function 1.
The variant retroaortic left renal vein traverses between the aorta and the vertebral column. It is proposed that the pulsation of an abdominal aortic aneurysm over time result in pressure necrosis and the development of a spontaneous aorto-left renal vein fistula. This is typically associated with a contained retroperitoneal rupture of the abdominal aortic aneurysm. Fistula formation leads to a drastic elevated left renal venous pressure, characterised by distended renal veins and an enlarged left kidney. When this venous pressure gradient overcomes the arterial pressure, the left kidney becomes non-perfused. Numerous venous collateral vessels, most often the paravertebral but also gonadal venous channels, become distended. Prompt diagnosis is critical to prevent venous infarction of the left kidney and ensuing mortality.
Post-traumatic aorto-left renal vein fistulas may result from complications of penetrating abdominal trauma (e.g. gunshot and stabbing injuries) 2-4.
CT / CTA
The imaging findings on CT complements on the pathophysiologic process described above. Careful multiplanar evaluation of the left posterolateral aspect of the aorta is paramount to identify the location of the fistula and site of the retroperitoneal abdominal aortic aneurysm rupture.
Beside the abdominal aortic aneurysm, a non-perfused and enlarged left kidney is often what catches the eye of the radiologist. Haemorrhage/haematoma in the renal pelvis is a common associated finding, although the exact mechanism is not elucidated. The constellation of all these features should prompt the radiologist of the diagnosis. The use of 3D reformat is a delight for the vascular surgeon.
Ultrasound / MRI / DSA
Duplex sonography, MRI and catheter angiography may also demonstrate the abnormal communication between the abdominal aorta and left renal vein as well as the associated findings 5.
Treatment and prognosis
Treatment options include surgical and endovascular repair. Mortality following repair of the aorto-left renal vein fistulas is less in cases caused by trauma compared to those formed as complications of abdominal aortic aneurysms 3.
- acute aortic syndrome
- thoracic aortic aneurysm
- abdominal aortic aneurysm
- endovascular aneurysm repair (EVAR)
- reporting tips for aortic aneurysms
- aortic coarctation
- aortic pseudocoarctation
- cervical aortic arch
- interrupted aortic arch
- transposition of the great arteries
- variant anatomy of the aortic arch
- traumatic aortic injuries
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- 2. Andreev AP, Guirov KG. Post-traumatic giant fistula between the aorta and the left renal vein: a case report. Int. J. Angiol. 2012;17 (4): 217-9. Free text at pubmed - Pubmed citation
- 3. Batt M, Hassen-Khodja R, Bayada JM et-al. Traumatic fistula between the aorta and the left renal vein: case report and review of the literature. J. Vasc. Surg. 1989;9 (6): 812-6. Pubmed citation
- 4. Mittal VK, Diaz-Velez A, Cortez JA et-al. Traumatic aorto-left renal vein fistula. Int Surg. 1983;67 (4): 367-9. Pubmed citation
- 5. Mansour MA, Russ PD, Subber SW et-al. Aorto-left renal vein fistula: diagnosis by duplex sonography. AJR Am J Roentgenol. 1989;152 (5): 1107-8. doi:10.2214/ajr.152.5.1107 - Pubmed citation