Profile of blood coagulation and fibrinolysis in chronic myeloproliferative disorders.

Blood coagulation and fibrinolysis were studied in 65 patients with chronic myeloproliferative disorders (MPD). They consisted of 28 patients with chronic granulocytic leukemia (CGL) in chronic phase, 7 with CGL in blast crisis, 9 with polycythemia vera (PV), 13 with primary thrombocythemia (PTh) and 8 with primary myelofibrosis (MF). Hemorrhagic and thrombotic complications were observed in 19 and 8 patients, respectively. Activated partial thromboplastin time and prothrombin time were prolonged in many patients. Low factor II levels were observed in some CGL patients. Factor V was decreased in CGL patients in chronic phase and in PV patients. Fibrinogen was either normal or increased in most patients, but an elevation of fibrin/fibrinogen degradation products (FDP) was found in some patients. The VIIIR: Ag/VIII:C ratio was increased in CGL patients in blast crisis, in PV patients and in PTh patients. Antithrombin III and plasminogen were below normal in some patients. Most patients showed a decrease in alpha 2-plasmin inhibitor. These findings suggest that blood coagulation and fibrinolysis are involved in the pathogenesis of the thrombotic and hemorrhagic complications in these patients. Chronic low-grade intravascular coagulation might be present in some patients with MPD.