Plasma levels of plasminogen activator inhibitor type 1, β-thromboglobulin, and fibrinopeptide a before, during, and after treatment of acute myocardial infarction with alteplase

Abstract

Plasma levels of plasminogen activator inhibitor type-1 (PAI-1), β-thromboglobulin (βTG), and fibrinopeptide A (FPA) were followed over 24 hours in 30 patients treated with alteplase for acute myocardial infarction. Samples were taken at baseline (T Oh), after 90 minutes (under alteplase, no heparin, T 1.5h), after 120 minutes (under alteplase and heparin, T 2h), 30 minutes after thrombolytic therapy (T 3.5h), as well as 12 hours (T 12h) and 24 hours (T 24h) after baseline. PAI-1 antigen levels (55 ± 9 ng/mL at T Oh, mean ± SEM) decreased to 35 ± 5 (T 1.5h) and 40 ± 6 (T 2h) ng/mL under alteplase, before increasing to 84 ± 22 (T 3.5h), 130 ± 30 (T 12h), and 64 ± 7 (T 24h) ng /mL after therapy, P < .005). We conclude that plasma levels of PAI-1 antigen as well as activity markedly increase after alteplase therapy of acute myocardial infarction. The high activity of PAI-1 and decreasing βTG levels suggest that platelets do not contribute significantly to this phenomenon. The marked increase of FPA levels under recombinant tissue-type plasminogen activator alone and its normalization under heparin emphasize the important role of concomitant anticoagulation in controlling further intravasal fibrin generation under alteplase. © 1991 by The American Society of Hematology.