Summary
Using a monoclonal antibody-based assay, we measured the fibrin degradation product
release in the supernatant of plasma clots obtained before and after venous occlusion
(VO) in 30 patients with definite or suspected vascular thrombosis (19 definite and
2 suspected deep vein thrombosis, 6 recurrent superficial thrombophlebitis, 3 arterial
occlusions of lower limbs). tPA and PAI-1 concentrations were determined using ELISA
assays; the post-occlusion values were corrected for haemoconcentration. The increase
in tPA during VO was correlated with haemoconcentration (r = 0.74), but 3 patients
had ineffective VO (<2% increase in proteins). The fibrinolytic response to VO was
evaluated using the shortening of the time necessary for the release of 200 μg of
fibrin degradation products per mg of fibrinogen (Δ T 200). Two among the 27 patients
with effective VO were bad responders with a Δ T 200 <3 h (whereas all the others
had Δ T 200 >10 h). These patients had respectively a deficient tPA release (Δ tPA
= 1 ng/ml) and an elevated PAI-1 level at rest (33 ng/ml). Several other patients
were bad responders in terms of tPA release or of shortening of the euglobulin clot
lysis time but they had a normal Δ T 200. This plasma clot test reflects the ability
of free tPA to bind to fibrin (the amount of which depends on the level of tPA and
PAI-1), and may be useful in the diagnosis of a hypofibrinolytic state.
Keywords
Thrombosis - Plasma clot lysis - Fibrin degradation products
