Aortoenteric fistulas. A study of 28 autopsied cases spanning 25 years.

Among 28 autopsied patients with aortoenteric fistulas, the mean age was 67 years (range, 19 to 91 years) and 23 (82%) were men. The most common causes were aortobifemoral bypass grafts (16 cases [57%]) and gastrointestinal carcinomas (6 cases [21%]). Fistulas developed at proximal anastomosis sites in 15 of 16 patients with grafts and were associated with radiation injury in 3 of 6 patients with carcinomas. Aortoenteric fistulas involved the duodenum in 16 (57%), esophagus in 9 (32%), and other gastrointestinal sites in 3 patients (11%). They involved the abdominal aorta in 20 cases (71%) and descending thoracic aorta in 8 cases (29%). Exsanguination from aortoenteric fistulas was the cause of death in 23 cases (82%). Major risk factors for aortoenteric fistulas are aortic bypass grafts and gastrointestinal carcinomas.