Bovine thrombin-induced factor V deficiency was thought to be a very rare acquired coagulopathy, with only three documented cases. We report a series of nine patients seen during a period of 32 months; these patients had normal preoperative coagulation profiles, and this unique coagulopathy developed 1 to 2 weeks after cardiovascular operations. The coagulopathy was characterized by a markedly elevated prothrombin time (40.9 +/- 5.8 seconds), an elevated activated partial thromboplastin time (96.3 +/- 12.2 seconds), a study positive for lupus anticoagulation (9/9), and markedly decreased levels of factor V (0.09 +/- 0.03 U/ml) and factor XI (0.04 +/- 0.02 U/ml), respectively. All patients had been exposed to commercially available bovine thrombin during prior cardiovascular or vascular operations and received a second bovine thrombin challenge during the latest procedure. Coagulopathic bleeding developed in four of the nine patients. Bleeding was unrelated to absolute fall in factor V level, but cessation of hemorrhage appeared to correlate with improvement in factor V level. Treatment with vitamin K, fresh frozen plasma, and platelet infusion were all unsuccessful in altering prothrombin time or factor V levels. Intravenous gamma globulin was used in three patients, two of whom were bleeding. All three patients showed a transient increase in factor V levels. Bleeding stopped in one of the two patients; the other continued to bleed and subsequently died. The third patient was treated prophylactically to increase factor V levels in preparation for flap reconstruction of his sternum. His factor V level increased from 0.26 to 0.49 U/ml, and he underwent the procedure without incident. Bovine thrombin-induced factor V deficiency may have been previously unrecognized. This deficiency should be suspected in patients who have undergone redo cardiovascular operations and in whom marked elevations in their prothrombin time occur 7 to 10 days after exposure to bovine thrombin. The resulting coagulopathy, although usually self-limited, has the potential to produce devastating bleeding complications. Intravenous gamma globulin (1 gm/kg during each of 2 days) has been used to increase factor V levels transiently but its role in therapy of this coagulopathy requires further investigation.
