Thrombolysis and fibrinolytic parameters during heparin treatment of deep vein thrombosis

Thirty-nine patients with symptomatic, venographically verified deep vein thrombosis (DVT) were studied during treatment with heparin in order to investigate the correlation between the venographic changes and parameters of heparin therapy or fibrinolytic components. Venograms were scored with a 40-grade scale, and after one week a significant improvement with an average reduction of the thrombi of 17% was observed. No statistically significant correlation was found between reduction of thrombus size and duration of heparin treatment, total amount of heparin administered, mean levels of APTT, plasmin-alpha 2-antiplasmin complex (PAP), tissue plasminogen activator (t-PA) antigen or t-PA-inhibitor. Only a short history of the thrombus was significantly correlated to thrombolysis. The concentrations of PAP and t-PA-inhibitor were not influenced, while that of t-PA antigen showed a significant increase during heparin infusion. Even if statistically significant correlations were not obtained, the patients with pronounced thrombolytic effect had high PAP-levels. Furthermore, patients with high t-PA-inhibitor levels had no lysis. The results suggest, that also other factors than plasminogen dependent fibrinolysis are of importance for the thrombolytic effect.