[Measurements of plasmin-alpha 2 plasmin inhibitor complex and FDP.D dimer levels in the fibrinolytic therapy of acute pulmonary thromboembolism].

The key enzyme for fibrinolysis is plasmin, which is converted from plasminogen by plasminogen activator. Activated plasmin lyses fibrinogen and fibrin to make fibrin degradation products(FDPs) and plasmin is inactivated immediately by alpha 2 plasmin inhibitor. As FDP.D dimer is derived solely from insoluble fibrin, FDP.D dimer is thought of as an index for clot lysis. We measured plasmin-alpha 2 plasmin inhibitor complex(PIC) and FDP.D dimer plasma levels in 3 patients with acute pulmonary thromboembolism treated with recombinant tissue plasminogen activator(tPA). Fifteen million units of tPA(TD-2061) were infused in one hour on the first, second and third hospital days. PIC and FDP.D dimer before tPA infusion showed slightly elevated values as compared to normal ranges. They increased markedly after tPA infusion. These findings suggest that the fibrinolytic system is slightly activated in the acute phase of pulmonary thromboembolism and also strongly activated by tPA infusion. Increased FDP D dimer suggests that fibrin clots are dissolved by activated plasmin. Improvement of arterial oxygen tension was observed after tPA infusion. As sustained higher FDP.D dimer means the existence of fibrin clots, heparin treatment should be continued for prevention of clot formation as long as FDP.D dimer shows higher value. In conclusion, PIC and FDP.D dimer are useful indices not only to detect the activated state of the fibrinolytic system but also to know clot lysis in tPA treatment.