ABNORMAL PLASMA FIBRINOLYSIS IN PATIENTS WITH RHEUMATOID-ARTHRITIS AND IMPAIRED ENDOTHELIAL FIBRINOLYTIC RESPONSE IN THOSE COMPLICATED BY VASCULITIS

Objectives-(a) To assess plasma fibrinolytic parameters in patients wi th rheumatoid arthritis (RA) and to determine whether there are differ ences between patients with RA alone and those with RA complicated by vasculitis. (b) To determine if patients with RA respond differently t o venous occlusion compared with normal subjects and to assess whether such a response differs in patients with RA alone and those with rheu matoid vasculitis. (c) To determine the extent of vascular damage in p atients with rheumatoid vasculitis and if this correlates with the lev els of plasma fibrinolytic parameters. Methods-Sixty three patients wi th RA (38 had RA only and 25 had evidence of rheumatoid vasculitis) we re recruited. Plasma levels of tissue plasminogen activator antigen (t -PA Ag), plasminogen activator inhibitor (PAI) activity, and factor VI II von Willebrand factor (vWF) were measured before and 10 minutes aft er venous occlusion. Results-Patients with RA, with or without rheumat oid vasculitis, had higher baseline PAI levels than control subjects. The difference was statistically significant for patients with RA alon e but was not statistically significant for patients with rheumatoid v asculitis. After venous occlusion, t-PA Ag levels increased significan tly in normal subjects and patients with RA alone, but not in patients with rheumatoid vasculitis. Plasma levels of vWF were significantly h igher in patients with rhematoid vasculitis than in normal subjects an d those with RA alone. In patients with RA alone, baseline vWF correla ted positively with t-PA Ag levels, whereas a negative correlation was found between these two parameters in patients with rheumatoid vascul itis. A negative correlation between vWF and t-PA Ag levels after veno us occlusion was also found in patients with rheumatoid vasculitis. Co nclusions-Patients with rheumatoid vasculitis showed evidence of vascu lar damage with increased levels of vWF and impaired t-PA Ag release a fter venous occlusion, a useful measurement of endothelial reserve to remove fibrin. This may be of pathophysiological importance in the dev elopment of vasculitis in these patients.