[Serial changes in hemostatic molecular markers after urokinase therapy of acute myocardial infarction].

We have examined the changes in fibrinolysis after urokinase administration for 6 patients with acute myocardial infarction. Patients were treated with urokinase with doses between 960,000 and 1,440,000 units, and fibrinolytic activities were determined by using newly developed molecular markers: alpha 2-plasmin inhibitor (alpha 2-PI), plasminogen, alpha 2-PI plasmin complex (PIC) and FDP D dimer. We also used classical hemostatic tests such as prothrombin time (PT) and plasma fibrinogen level. These tests were measured with 1 to 2 hour intervals, during the first 6 hours of therapy, daily during the next 3 days, and subsequently on day 7 and 14. The initial intravenous administration of urokinase with a dose of 460,000 units produced a significant decrease in alpha 2-PI level, but induced only minimal changes in the level of fibrinogen, FDP-E, and FDP D-dimer, suggesting that enhancement of fibrinolytic activity was less pronounced under such therapy. This might be due to the ability of residual amounts of alpha 2-PI to sufficiently inhibit plasmin generation in the circulating blood. However, a subsequent injection of 960,000 units of urokinase into the coronary artery induced a profound reduction in the alpha 2-PI to an unmeasurable level, and resulted in a marked enhancement of fibrinolytic activity. The elevation of FDP-E and FDP D-dimer was accompanied with this decrease in alpha 2-PI and persisted for more than 6 hours after urokinase injection. Prolongation of PT due to decrease in fibrinogen level was also observed over 6 hours.(ABSTRACT TRUNCATED AT 250 WORDS)