[Aortoduodenal fistula as a cause of gastrointestinal bleeding--difficulties in endoscopic diagnosis].

We report on three patients with severe gastrointestinal bleeding arising from aortoenteric fistula. Two patients presented with a secondary aortoduodenal fistula. In the first case bleeding occurred 8 months after aortobifemoral graft implantation. In the second patient aortobiliacal graft implantation was performed 22 years before. In the third case the aortoenteric fistula was primary and was caused by an abdominal aortic aneurysm without prior vascular intervention. In the first case diagnosis was made by urgent endoscopy visualizing ongoing bleeding from the duodenal fistula. In the two other patients urgent endoscopy and CT as well could not demonstrate the bleeding source. Aortoenteric fistula was diagnosed endoscopically during severe rebleeding some hours later. Two patients underwent surgery with implantation of an axillobifemoral bypass; the third patient declined further intervention and died. The course shows that aortoduodenal fistula can present with severe but intermittent gastrointestinal bleeding making the diagnosis in the non-bleeding interval difficult. In patients with severe gastrointestinal bleeding and a history of aortic disease (aneurysm, prior aortic graft repair or stenting) an aortoduodenal fistula should be suspected and the indication for surgical intervention should be considered early in spite of negative results of endoscopy and CT.