Aortic-caval fistula from ruptured abdominal aortic aneurysm.

Four cases of spontaneous aorto-caval fistula are reported. All cases were successfully treated by suture of the fistula from the inside of the aortic aneurysm, which was replaced by a dacron graft. All patients are alive and well at follow up after one, three, four and twelve years, respectively. In one patient pulmonary and circulatory haemodynamics were recorded preoperatively as well as in the early and late postoperative period. Preoperative high pulmonary artery and capillary wedge pressures and cardiac output were rapidly reduced to almost normal values after the operation. An intrapulmonary shunt fraction of 58 % preoperatively was reduced to 15 % shortly after closure of the fistula. Possible mechanisms causing the high pulmonary shunt fraction are discussed.