FIBRINOGEN, T-PA, AND PAI-1 PLASMA-LEVELS IN PATIENTS WITH PULMONARY-HYPERTENSION

We measured fibrinogen levels as well as the fibrinolytic parameters t issue-type plasminogen activator (t-PA) and plasminogen activator inhi bitor 1 (PAl-1) in plasma samples obtained at basal conditions and aft er stimulating the fibrinolytic system by venous occlusion (VO). Sampl es were taken from patients with primary pulmonary hypertension (PPH), with secondary thromboembolic pulmonary hypertension (SPHTH), with se condary pulmonary hypertension due to congenital heart disease with Ei senmenger's reaction (SPHCD), and from healthy control individuals (CO N). Fibrinogen levels were not significantly different between the gro ups with PPH and SPHTH or between SPHCD and CON. The latter groups, ho wever, exhibited significantly lower fibrinogen plasma levels compared with PPH or SPHTH (p < 0.01). Basal plasma levels of t-PA antigen, t- PA activity, and PAl-1 activity, respectively, did not differ signific antly between the study groups. After VO, mean t-PA activity levels in creased to a higher extent in control subjects compared with patients with PPH, or SPHTH, or SPHCD, with significant differences only betwee n CON and SPHTH or CON and PPH (p < 0.03). Patients with PPH and SPHTH exhibit both increased fibrinogen plasma levels and a diminished fibr inolytic response compared with healthy subjects. Moreover, the fibrin ogen plasma levels in patients with SPHCD are in normal range, and the fibrinolytic response is similar to CON compared with PPH and SPHTH, thus indicating the existence of a comparable prothrombotic situation in patients with PPH and SPHTH.