Bovine thrombin-induced inhibitor of factor V and bleeding risk in postoperative neurosurgical patients. Report of three cases.

Three patients are reported who developed topical bovine thrombin-induced antibodies to clotting factor V following neurosurgical procedures. In each patient the coagulopathy occurred within 8 to 13 days following exposure to topical bovine thrombin at surgery. Two of the three had previously been exposed to bovine thrombin during cardiothoracic surgery. The three patients were identified by detection of a prolonged prothrombin time, ranging from 20.5 to 39.8 seconds. The patient with the highest factor V level (0.12 U/ml) experienced gastrointestinal bleeding, which ceased when the factor V level increased to more than 0.20 U/ml. One patient required a ventriculostomy. In that case the prothrombin time and factor V level failed to improve following administration of vitamin K, 10 units of fresh frozen plasma, and platelet transfusions; the factor V level temporarily increased from 0.03 to 0.32 U/ml following a 2-day course of intravenous gamma globulin (1 gm/kg/day). Plasmapheresis has also been reported to be transient benefit in the treatment of this coagulopathy. In most patients the factor V level rises and the prothrombin time improves toward normal within 3 to 6 weeks following surgical exposure. The individuals identified likely represent only a fraction of the patients who develop the coagulopathy. The latter either do not bleed or are not sufficiently challenged in the postoperative period for the bleeding risk to be tested. It is concluded that bovine thrombin-induced coagulopathy may occur following surgical exposure to topical bovine thrombin and may result in both postoperative morbidity and mortality in a subset of patients.