Plasminogen, alpha₂-antiplasmin, and protein C decline following infusions of recombinant tissue plasminogen activator

We examined a variety of hemostatic functions in a subset of patients participating in a multicenter trial of rt-PA in the treatment of DVT. There were declines in systemic levels of plasminogen and alpha₂-antiplasmin at 24 hours following therapy. Additionally, levels of protein C antigen and protein C activity were also seen to decrease over the same time course. We propose that therapy with rt-PA has more systemic effects than previously thought and suggest that the effect on protein C may have some role in reocclusion following thrombolysis.