fibrinopeptide-a and Polycythemia-Vera

Platelet function and the clinical course of the disease were prospectively investigated in 29 patients with myeloproliferative disorders. Serial determinations (median: 5 investigations per patient within 17 months) of platelet aggregation, plasma and intraplatelet concentrations of beta-thromboglobulin (beta TG) and platelet factor 4 (PF4), and of fibrinopeptide A (FPA) plasma levels were carried out. In the chronic phase of polycythaemia vera, patients with thrombohaemorrhagic complications during the study period had higher platelet count, more severe platelet aggregation defects, and increased plasma levels of beta TG and FPA compared to patients without complications. However, thrombohaemorrhagic complications were not predicted by changes in these parameters in the individual patient during the chronic disease phase. When patients with chronic myelogenous leukaemia entered blast crisis, bleeding complications were related to thrombocytopenia, impaired platelet function and low intraplatelet concentrations of beta TG and PF4. Cytoreduction by chemotherapy in the chronic phase of CML did not alter beta TG and PF4 plasma levels, whereas treatment of polycythaemia rubra vera by venesection favourably influenced platelet alpha-granule secretion and increased intraplatelet concentrations of beta TG and PF4.

Topics: Adult; Aged; beta-Thromboglobulin; Blood Platelets; Female; Fibrinopeptide A; Hemorrhage; Hemostasis; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukocyte Count; Male; Middle Aged; Myeloproliferative Disorders; Platelet Aggregation; Platelet Count; Platelet Factor 4; Polycythemia Vera; Primary Myelofibrosis; Prospective Studies; Thrombocythemia, Essential; Thrombosis

The in vivo platelet release reaction in 22 patients with myeloproliferative disorders has been studied by measuring plasma concentrations of the platelet release product beta-thromboglobulin (beta TG). Mean beta TG and mean beta TG: whole blood platelet count ratio were significantly raised in the patient group taken as a whole compared to an age matched control group. No significant increases were observed in the plasma concentrations of thrombin and plasmin sensitive fibrinogen fragments fibrinopeptide A (FpA) and B beta 1-42. The patients were divided into those who had normal, increased or decreased responses to in vitro ADP-induced platelet aggregation. Mean beta TG and the mean beta TG: whole blood platelet count ratio were higher in the increased and decreased responders to ADP than in the normal aggregation group, but the differences in means were not statistically significant. Aspirin given to six patients at a dose sufficient to eliminate the secondary phase of ADP-induced platelet aggregation reduced mean beta TG and the mean beta TG: whole blood platelet count ratio but did not alter mean FpA and B beta 1-42. It is concluded that the enhanced platelet release reaction seen in myeloproliferative disorders is independent of plasma protease activity that arises when coagulation and fibrinolytic systems are activated.

Topics: Aged; Aspirin; beta-Thromboglobulin; Blood Platelets; Fibrinopeptide A; Fibrinopeptide B; Humans; Middle Aged; Myeloproliferative Disorders; Platelet Aggregation; Platelet Count; Polycythemia Vera; Primary Myelofibrosis

The prompt reduction of elevated fibrinopeptide A (FPA) levels (normal less than 1.3 pmole/ml) by heparin therapy in patients with thromboembolism suggests that measuring the FPA level may provide a good index of disease activity and be a useful method of monitoring therapy. Sepsis or malignancy may elevate FPA levels and coexist with thromboembolism. FPA levels were surveyed in 51 patients with thromboembolism (including 15 with concurrent sepsis or malignancy) during heparin treatment in an attempt to distinguish the effects of coexistent disease and the progression of thromboembolism. The anticoagulant effect of heparin was within the therapeutic range for 81% of the study period. In patients with thromboembolism alone and marked resolution of emboli on repeat lung scan, the mean daily FPA levels were lower than the values in patients with minimal resolution (p less than 0.005). In patients with marked resolution of pulmonary embolism or venous thrombosis and a concurrent disorder, the mean FPA level remained elevated compared to normal values in patients with thromboembolism alone. These results suggest that FPA levels monitored during heparin therapy of thromboembolism may be useful as an index of disease activity except in the presence of coexisting sepsis or malignancy.

Topics: Adenocarcinoma; Adult; Aged; Anticoagulants; Carcinoma, Squamous Cell; Female; Fibrinogen; Fibrinopeptide A; Heart Failure; Heparin; Humans; Leukemia, Lymphoid; Lupus Erythematosus, Systemic; Male; Middle Aged; Polycythemia Vera; Pulmonary Embolism; Sepsis; Thromboembolism