A 78-year-old man with a history of
hypertension was admitted for a fall with
back pain. The blood pressure was at 110/50 mmHg and the pulse at 115 b.min-1. A pulsatile abdominal mass was palpated. No signs of
respiratory insufficiency or
congestive heart failure were found. The diagnosis of
abdominal aortic aneurysm was promptly confirmed by echography. Before
laparotomy, a pulmonary artery
catheter was inserted for haemodynamic monitoring which showed a
high cardiac output, low systemic vascular resistances, increased pulmonary artery wedge pressure and a high SvO2 (93%). This was not consistent with a hypovolaemic
shock but rather an aortocaval
fistula. After incision and aortic clamping,
surgical procedure consisted of transaortic closure of the
fistula and restoration of arterial continuity with a prosthetic graft. Initial control of venous
bleeding was obtained by passing a Foley's
catheter distally and by clamping the vena cava. The postoperative course was initially satisfactory. The patient was extubated, but remained with a major
renal insufficiency. After a stay of 15 days in the intensive care unit, he died from
nosocomial pneumonia. Aortocaval
fistulas are either traumatic or spontaneous. Spontaneous
fistulas are more common, and in about 90% of the cases result from a
rupture of an atherosclerotic
aortic aneurysm. Clinical findings include signs of
high cardiac output symptoms of venous
hypertension and regional arterial insufficiency. Haemodynamic changes can be of value for the recognition of an aortocaval
fistula. Most authors emphasize the importance of preoperative diagnosis, allowing the use of appropriate operative techniques and a prompt control of the
fistula. This could decrease haemodynamic instability and transfusion requirements.