[Relation between post-thrombotic syndrome, ADP-induced thrombocyte aggregation and intrathrombocyte calcium content]

Correlation between postthrombotic syndrome, ADP-induced aggregation and intracellular calcium concentration. This study presents a comparison of the ADP-induced platelet aggregation and free cytosolic platelet calcium concentration between patients with postthrombotic syndrome and healthy volunteers. The half maximal effective dose of the platelet aggregation induced by ADP was significantly decreased in postthrombotic syndrome (p less than 0.005). The mean values were 0.42 mumol/l in postthrombotic syndrome (n = 22) and 1.00 mumol/l in normal controls (n = 25). The free intracellular calcium concentration was slightly but significantly diminished in patients compared with healthy volunteers. In both groups there was seen a remarkable interindividual spread of platelet calcium concentrations. There was seen no significant correlation between cytosolic calcium concentration of platelets and the half maximal effective dose of ADP-induction. Therefore the considerable enhanced aggregability in postthrombotic syndrome cannot explained with altered cytosolic calcium content of platelets.