HEMODYNAMIC DIAGNOSIS OF AN AORTOCAVAL FI STULA COMPLICATING AN AORTIC-ANEURYSM

A 78-year-old man with a history of hypertension was admitted for a fa ll 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 o f respiratory insufficiency or congestive heart failure were found. Th e diagnosis of abdominal aortic aneurysm was promptly confirmed by ech ography. Before laparotomy, a pulmonary artery catheter was inserted f or haemodynamic monitoring which showed a high cardiac output, low sys temic vascular resistances, increased pulmonary artery wedge pressure and a high Svo2BAR (93 %). This was not consistent with a hypovolaemic shock but rather an aortocaval fistula. After incision and aortic cla mping, surgical procedure consisted of transaortic closure of the fist ula and restoration of arterial continuity with a prosthetic graft. In itial control of venous bleeding was obtained by passing a Foley's cat heter distally and by clamping the vena cava. The postoperative course was initially satisfactory. The patient was extubated, but remained w ith a major renal insufficiency. After a stay of 15 days in the intens ive care unit, he died from nosocomial pneumonia. Aortocaval fistulas are either traumatic or spontaneous. Spontaneous fistulas are more com mon, and in about 90 % of the cases result from a rupture of an athero sclerotic aortic aneurysm. Clinical findings include signs of high car diac output symptoms of venous hypertension and regional arterial insu fficiency. Haemodynamic changes can be of value for the recognition of an aortocaval fistula. Most authors emphasize the importance of preop erative diagnosis, allowing the use of appropriate operative technique s and a prompt control of the fistula. This could decrase haemodynamic instability and transfusion requirements.