When Imaging is Negative: Endoscopic Diagnosis of a Secondary Aortoduodenal Fistula.

Aortoenteric fistula is a life-threatening aortic graft complication with a narrow opportunity for treatment. We present a patient with aortobifemoral bypass who developed recurrent anemia and melena. Despite previous upper endoscopy and colonoscopy, computed tomography angiogram, and tagged red blood cell scan, his symptoms were persistent. Capsule endoscopy showed blood in the duodenum. Push enteroscopy revealed graft erosion in the duodenum, confirming aortoduodenal fistula. He underwent aortobifemoral graft excision, and resection of the third portion of the duodenum with end-to-side duodenojejunostomy, highlighting the importance of endoscopy in timely diagnosis of aortoenteric fistulae.