Spontaneous aortocaval fistulas.

An aortocaval fistula is an uncommon complication of an abdominal aortic aneurysm and occurs in approximately 1-3% of cases. Successful surgical intervention is dependent upon a preoperative diagnosis and subsequent modification of surgical technique. As abdominal aortic aneurysms increase in frequency so will the need to recognize this complication and treat it successfully.