The Significance of Hypofibrinolysis for the Risk of Recurrence of Venous Thromboembolism

Abstract

An impaired fibrinolytic function has been described in several case-control studies of patients with venous thromboembolism (VTE). In the present study the correlations between some fibrinolytic compounds and future recurrent VTE were investigated. Blood samples for analysis of tissue-type plasminogen activator (t-PA) antigen before and after 10 min of venous occlusion (V.O.) and plasminogen activator inhibitor type 1 (PAI-1) activity were taken at 6 months after the first episode of VTE or the first recurrent VTE in 784 and 207 patients, respectively, who were anticoagulated for 1.5 or 6 months (first VTE) and 6 months or indefinitely (first recurrence). During a follow-up of 3-6 years from the event which qualified for inclusion there have been 177 recurrences. All initial and recurrent events were verified with objective diagnostic methods. Using cut off points of 10.0 ng/ml for t-PA antigen before V.O. and 30 AU/ml for PAI-1 in samples taken at rest, there were more patients above those levels in the groups with than without further recurrence (t-PA antigen, 50% versus 36%, p = 0.001; PAI-1, 18% versus 12%, p = 0.045). In the 495 patients, who received oral anticoagulation for 6 months, t-PA antigen at rest discriminated better, with 59% versus 34% of patients above 10 ng/ml in the groups with and without recurrence, respectively (p * The investigators constituting the DURAC Trial Study Group, along with their institutions, are listed in the Appendix