Summary
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 <0.001).
The t-PA antigen levels after V.O. and the fibrinolytic capacity (t-PA antigen after
V.O. minus t-PA antigen before V.O.) were distributed similarly in patients with and
without new recurrences. There was a statistically significant positive correlation
between age and t-PA antigen (p <0.001), and by analysis of covariance the difference
between the groups with and without further recurrence regarding t-PA antigen disappeared.
In conclusion, increased levels of PAI-1 and t-PA antigen in VTE-patients correlate
with development of recurrent VTE within the next 3–6 years, but the value of these
components in predicting future events for the individual patient is limited.
