Haemostatic disturbances in essential thrombocythosis

Essential thrombocythemia (ET) is one of the chronic myeloproliferative disorders which is characterized by megakaryocytic metaplasia. The most common complications of ET are thrombohemorrhagic events. The overall incidence of thrombosis is 70% and hemorrhagic events about 10-15%. We investigated 21 patients with ET. Median age was 51.0 (range 41-61 years). 29 healthy controls were similar in aspects of sex and age. Patients had examined whole blood count, blood smear, platelet counts, prothrombin time (PT), activated partial thromboplastin time (aPTT), euglobulin lysis time (ELT), fibrin degradation products (FDP), thrombin-antithrombin III complexes (TAT), plasmin-alpha2-antiplasmin complexes (PAP), antigen of tissue and urokinase plasimogen activators (t-PA:Ag, u-PA:Ag), antigen of tissue plasminogen activator inhibitor types 1 and 2 (PAI-1:Ag, PAI-2:Ag), fibrinogen, antitrombin (AT) and alpha2-antiplasmin (alpha2-AP) activity. TAT concentraction (26.83 ng/ml) was significantly higher in ET group than in controls (3.41 ng/ml). We also showed in patients with ET significantly prolonged aPTT (50.12 s) and elevated platelet count (859.5 G/l). Fibrinolytic parameters PAI-1:Ag (56.2 ng/ml) and PAP (662.5 ng/ml) were significantly higher in patients with ET. High TAT concentration means enhanced thrombinogenesis and prolonged aPTT-disturbances in coagulation activation process. A cause of increased plasminogenesis is increased concentration of PAP.