Effects of Co-infusion of Plasma, Whole Blood and Anticogulants on Their Clotting Activities

Aims: Nafamostat mesilate (NM), a protease inhibitor is available for treating acute pancreatitis and disseminated intravascular coagulopathy and it is used as an anticoagulant for hemodialysis in Japan. A plasmapheresis circuit using NM can easily be blockaded. Therefore, we investigated the influence of co-infusion of fresh frozen plasma (FFP), whole blood and NM on clotting activities mainly in the static condition compared with other anticoagulants including heparin sodium and gabexate mesilate.

Study Design: In vitro study.

Methodology: We investigated the effect of co-incubation of expired FFP and various concentrations of NM (0–0.1mg/mL). We measured the plasma fibrinogen level and activities of factor XIII, anti-thrombin III, protein C (PC) and protein S (PS). In addition, we examined the influence of NM on coagulation tests using whole blood from healthy volunteers.

Results: NM reduced PC and PS activities in FFP, although it did not affect plasma fibrinogen levels or the activities of anti-thrombin III or factor XIII. While anti-thrombin III activity and plasma fibrinogen level increased in NM-containing whole blood, PC and PS activities decreased. Gabexate mesilate, sodium heparin and citrate did not reduce the activities of PC or PS.

Conclusion: Co-infusion of FFP, whole blood and NM reduces PC and PS activities and we speculate that it may lead to the obstruction of the plasmapheresis circuit when using NM as an anticoagulant.