FIBRINOLYTIC RESPONSE TO VENOUS OCCLUSION IN PATIENTS WITH HOMOZYGOUSSICKLE-CELL DISEASE

The fibrinolytic potential was evaluated in 37 patients with homozygou s sickle cell disease and compared to a control group of 30 age- and s ex-matched healthy volunteers. In all individuals, the euglobulin clot lysis time and plasma antigen levels of t-PA and PAI-1 were measured before and after venous occlusion (v.o) for 10 min. The global fibrino lytic activity was normal in 4 patients (good responders to v.o), whil e it was decreased in 33 patients (poor responders to v.o). Among the latter, 22 patients had significantly increased baseline levels of PAI -1 Ag (82.6 +/- 27.5 ng/ml, p < 0.001) and a normal release of t-PA Ag after v.o. In contrast, 11 patients had basal values of PAI-1 Ag comp arable to those in controls with a defective release of t-PA Ag after v.o (11.4 +/- 5.2 ng/ml, p < 0.01). These data provide evidence for re duced fibrinolytic capacity resulting from either increased basal leve ls of PAI-1 or defective release of t-PA.