- Arterio-venous fistula is a relatively rare form of vascular injury. A case of an unusual fistula between aorta and inferior vena cava is presented. Occasionally this type of injury is difficult to diagnose early. Life-threatening conditions may mandate prompt treatment and the use of damage control strategy. It is also important to diagnose and treat this injury in order to prevent complications. Sudden hemorrhage and congestive heart failure are the major disturbances that result from aortocaval fistula.