Randomised placebo controlled double blind study of two low dose aprotinin regimens in cardiac surgery

To determine whether two low dose aprotinin regimens produce clinically significant reductions in postoperative blood loss compared with a control group.

A randomised double blind placebo controlled study.

A regional cardiothoracic unit in London.

79 patients were consecutively allocated to one of three groups. All patients had primary elective surgery with standard anaesthetic and surgical techniques, and no patients were withdrawn from the study.

Group K patients (n = 27) received aprotinin (10(6) kallikrein inactivator units (KIU) into the pump prime whereas group L patients (n = 27) received an intravenous bolus of aprotinin (0.5 x 10(6) KIU) after induction of anaesthesia and 10(6) KIU was added to the pump prime. A third group (group J, n = 25) received 0.9% saline placebo.

After insertion of the chest drains at the end of cardiopulmonary bypass, blood losses were measured hourly until the drains were removed 18 to 24 h later. Total haemoglobin loss into the chest drains was calculated.

Both aprotinin treated groups showed significantly less postoperative blood loss than controls (medians: group K, 400 ml; group L, 400 ml; v controls 780 ml; p < 0.001) and there was even less measured postoperative haemoglobin loss within the chest drains in both the aprotinin treated groups than in the controls (medians: group K, 16 g; group L, 19 g; v controls, 47 g; p < 0.001).

In primary cardiac surgery the dose of aprotinin may be reduced by about 80% from the recommended high dose schedule and still significantly reduce postoperative blood loss compared with placebo.