Secondary aortoduodenal fistula with a fatal outcome: report of six cases.

Secondary aortoenteric fistulas (AEFs) are a well-known but uncommon cause of gastrointestinal hemorrhage. They usually occur secondary to reconstructive surgery of an abdominal aneurysm. We report six cases of secondary aortoduodenal fistulas, involving patients who, despite presenting with classic "herald bleeding," died as a result of delayed operative intervention. We also discuss the pathogenesis, clinical presentation, and diagnosis of AEFs, emphasizing the value of clinical suspicion and negative endoscopy in establishing the diagnosis and the need for early operative intervention.