Summary
We examined recombinant activated factor VII (rVIIa) administered by continuous infusion
to eight patients with inhibitors to factor VIII, undergoing elective surgery. rVIIa
was infused at a fixed rate of 16.5 μg/kg/h for a median of 13.5 days (range 1-26).
There was effective haemostasis at this infusion rate in only one of two minor procedures
and two of six major operations. Three patients experienced excessive bleeding despite
plasma factor VII activity around 10 IU/ml. Serious bleeding occurred in two other
patients caused by procedural errors unrelated to rVIIa and required re-operation.
The median rVIIa clearance on day 1 was 57 ml/h/kg (range 18-100) and on day 3 was
100 ml/h/kg (range 61-200). Clearance on the final infusion day was not significantly
different from day 3. The infusion did not induce pathological activation of the coagulation
mechanism. The only thrombotic adverse events were two episodes of superficial thrombophlebitis
of the infused vein in one subject. In conclusion, the 16.5 μg/kg/h infusion rate
reliably achieves plasma factor VII activity levels of 10 IU/ml, but this level does
not provide reliable haemostasis.
Keywords
Recombinant factor VIIa - continuous infusion - surgery - inhibitor