Evaluation of haemostatic parameters and circadian variations of the haemostatic system in patients with systemic sclerosis and Raynaud's phenomenon

Background. Systemic sclerosis (SSc) is a multisystemic disease characteriz ed by proliferation and swelling of endothelial cells and other disorders, Raynaud's phenomenon (RP) is a disturbance, with unknown pathogenesis, that may be a precursor to SSc. The aim of this study was to investigate possib le alterations in the haemostatic system and to examine whether there is a circadian variation in haemostatic variables at the initial stage of SSc. Methods. In 20 patients with RP (in all patients secondary to SSc) and in 1 0 controls the levels of thrombomodulin (TM), beta-thromboglobulin (beta-TG ), D-dimer (DD), tissue-type plasminogen activator (t-PA) and plasminogen a ctivator-inhibithor (PAI-1) were measured In venous plasma samples taken at 9.00 and 14.00. Results. Only TM levels were found to be higher in patients than in control s. Moreover the PAI-I levels, in the patient group, showed a significant ci rcadian rhythm (with peak values at 9.00). No significant circadian variati ons for the other parameters were detected. Conclusions. These data seem to indicate that in patients with RP there is an endothelial damage reflected by a significant elevation of the TM plasma level and a circadian variation in plasma PAI-1, which was higher in the m orning. This observation may be an area worth exploring for its importance potential In the knowledge of Raynaud's phenomenon.