Increased fibrinopeptide A after prothrombin complex concentrates

Prothrombin complex concentrates (PCC) are known to carry a risk of thromboembolism. We have chosen to reassess the problem of detecting in vivo signs of activation of the clotting mechanism by assaying fibrinopeptide A (FpA) after PCC administration in hemophilic patients during bleeding episodes. FpA was significantly increased above baseline levels 15 to 60 min after the infusion of 19 doses of 5 different types of commercial PCC in 14 hemophilia B patients treated for bleeding episodes or dental extractions. A more marked increase followed 16 infusions of the activated PCC FEIBA and Auto IX in 4 hemophilia A patients with F. VIII inhibitors. There was no significant FpA change after F. VIII concentrates administered to a control group of 7 patients with hemophilia A. These findings suggest that circulation of thrombin occurs frequently after PCC administration, even though clinical manifestations of thromboembolism appear to be relatively rare.