Endovascular coil embolization of inferior mesenteric artery to ileal-conduit fistula: a case report.

Background: Uretero-arterial fistulas (UAFs) are uncommon and pose a diagnostic dilemma, making them life threatening if not recognized and treated expediently. UAFs to small arteries such as a branch of the inferior mesenteric artery (IMA) are very uncommon and present a further diagnostic and treatment challenge. There should be a high index of suspicion for UAFs when intervening on patients with history of treated pelvic cancers and long-standing ureteric stents experiencing hematuria not attributable to another cause.

Case Presentation: We present a case of a fistula formed between a distal branch of the IMA-superior rectal artery-and an ileal-conduit in a patient with a long-standing reverse nephroureterostomy (Hobbs) catheter presenting with abdominal pain and hematuria through the conduit. During a tube exchange, contrast injection demonstrated a fistula with the superior rectal artery, multiple ileal intraluminal blood clots, and active extravasation. The patient became tachycardic and hypotensive, actively bleeding through the ileal-conduit, prompting a massive transfusion protocol. Successful endovascular coiling of the superior rectal artery was performed with resolution of active extravasation and stabilization of the patient. The patient recovered and was discharged in stable condition 10 days later.

Conclusions: Although UAFs are uncommon, our case demonstrated key predisposing risk factors to fistula development; pelvic cancer surgery, pelvic radiation, and a prolonged ureteric stent through the ileal-conduit. Typically, UAFs arise from communication with the iliac arterial system, however in this instance we have demonstrated that fistulization to other arterial vessels is also possible. Endovascular management has become the preferred method of therapy, typically involving the placement of covered stents when involving the iliac arterial system. In this instance stent grafting was not possible due to the small caliber vessel and therefore had to be embolized.