IS Case 286: Arterioureteral fistula
Imaging Sciences URMC 2009
Publication Date: 2009-08-05
History
Patient is a 56 year-old female seen for routine left-sided nephroureteral stent check and change. She has a history of aortobifemoral graft, with subsequent left-to-right femorofemoral (fem-fem) bypass revision.
Findings
Fluoroscopy images demonstrate a left-sided nephroureteral stent, with multiple surgical clips seen in the area of the pelvis. The patient has had multiple pelvic surgeries, including an aortobifemoral graft with revision, which predispose her to the formation of an arterioureteral fistula.
CT images from a separate patient with left-sided arterioureteral fistula demonstrate a left perinephric and subcapsular hematoma with hemorrhage seen in the pelvicalyceal collecting system and surrounding fat-stranding. The left nephroureteral stent can be seen crossing the left common iliac artery and there is a urostomy seen at the anterior abdominal wall
Diagnosis
Arterioureteral fistula
Discussion
The extravasation of contrast from the left ureter and around the left iliac graft in the above fluoroscopy images represents what is likely an impending arterioureteral fistula. The CT images are from a separate patient that had progressed to such a fistula, with hemorrhage seen in the area of the left kidney and reportedly coming from the urostomy.
Arterioureteral fistulas are uncommon but potentially life-threatening causes of hemorrhage that usually manifest as hematuria. Predisposing factors include pelvic surgery, chronic ureteral stents (especially rigid ones), pelvic irradiation, and vascular reconstructive surgery. Morbidity and mortality rates are high, with 23% mortality reported from 1980-1997. The common or external iliac artery is usually the artery involved, although the internal iliac artery and and aorta have also been involved.
Arterioureteral fistulas are classified into three categories, including primary, secondary (iatrogenic), and pregnancy-related. Primary fistulas account for less than 15% and are seen mainly in cases of aortoiliac aneurysmal disease. Secondary fistulas account for approximately 85% and are often in association with irradiation, retroperitoneal fibrosis, ureteral stenting, or after vascular surgery with synthetic grafting. Pregnancy-related fistulas are significantly more rare and are often diagnosed postmortem, after massive hemorrhagic complications. Ureteral stenting has been reported in cases after the pregnant patient developed urinary obstruction.
The pathophysiology is not well understood but is thought to be related to inflammatory or ischemic change to the ureters, iliac vessels, or both. Inflammation may fix the ureter to the artery or graft. A chronic ureteral stent may act as a firm strut and facilitate transmission of arterial pulsations to an already compromised ureter, producing necrosis and fistula formation.
While there are several possible treatments, covered endovascular stent-grafts may represent the best therapeutic option for these patients.
References
- Madoff DC, Gupta S, Toombs BD, et al. Arterioureteral fistulas: a clinical, diagnostic, and therapeutic dilemma. AJR Am J Roentgenol. 2004 May;182(5):1241-50. PMID: 15100126 [PubMed]
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