COAGULATION STUDIES IN PATIENTS TREATED WITH DEFIBRASE

Abstract. Coagulation studies have been carried out on 33 patients who were anticoagulated by induced hypofibrinogenemia, by using Defibrase, a purified thrombinlike enzyme from the venom of Bothrops atrox. Patients were given 50–150 μl Defibrase/kg b.wt./day, maintaining fibrinogen concentrations around 0.7 mg/ml plasma for 4–21 days. Soluble fibrin appeared in the circulation during the initial phase of treatment. Though not demonstrable in plasma an increased fibrinolytic activity was indicated by an increased amount of fibrin(‐ogen) degradation products in the serum and a partial depletion of the plasma concentration of plasminogen and α2‐macroglobulin. The degree of plasminogen depletion was correlated to the degree of defibrination. During Defibrase treatment the concentration of factor XIII fell, whereas no reduction was observed for the concentrations of coagulation factors II, V, VIII, X and XII or for the prothrombin‐proconvertin test and Normotest values. The concentration of antithrombin III was unaffected by the Defibrase treatment. A sensitivity reaction was suspected in one patient, but in none of the patients was an increased capacity to neutralize Defibrase demonstrated. The results are discussed with regard to hemostasis and anticoagulant effect. It is concluded that Defibrase treatment is comparable to other common anticoagulant treatments.