Evaluation of fibrinolytic therapy by measuring cross-linked fibrin derivatives and plasmin-alpha 2-plasmin inhibitor complex in plasma.

Plasma levels of alpha 2-plasmin inhibitor (alpha 2PI), plasmin-alpha 2PI complex and cross-linked fibrin derivatives (XDP) were measured in 8 patients (12 episodes) with thromboembolic disorders on the initial administration of urokinase. In conjunction with a decrease in plasma alpha 2PI activity and antigen, plasmin-alpha 2PI complex increased following urokinase infusion in all cases except one who received a low dose (60,000 units) of urokinase. However, changes in XDP were variable among the patients. Plasma XDP level increased markedly in one, moderately in 4, slightly in one, and remained unchanged in 6 cases (episodes). The increment of plasma XDP correlated (r = 0.804, p = 0.003) with the dose of urokinase administered, but was independent of changes in plasmin-alpha 2PI complex. The plasma XDP elevation was associated with clinical improvement. These results suggest that simultaneous measurements of XDP and plasmin-alpha 2PI complex in plasma would be valuable for the pharmacological or hemostatic assessment of thrombolytic therapy.