Significance of fibrinopeptide A as an indicator for coagulative analysis in thrombotic diseases

This study was made to know the significance of fibrinopeptide A(FPA) as an indicator for coagulative analysis in thrombotic diseases. In normal control subjects (n=21), values of FPA by the radioimmunoassay were 0.5 +/- 1.4 ng/ml (mean +/- SD). In animal models, using Lyoplastin (tissue thromboplastin, n=5) or Ancrod (n=5) to piglets, plasma FPA levels elevated rapidly as a reflection of fibrin formation, and these changes of FPA were found to be most rapid and sensitive among the indicators for coagulation and fibrinolysis. In patients with thrombosis (n=32), elevated FPA levels (14.7 +/- 13.8 ng/ml) and beta-thromboglobulin (beta-TG)(86.1 +/- 65.6 ng/ml) were found. FPA levels in these patients positively correlated to beta-TG (r=0.5539, P less than 0.05) and inversely to fibrinogen (fbg) (r= -0.3622, P less than 0.05). In patients with acute myelocytic leukemia (AML, n=112), acute promyelocytic leukemia (APL, n=18) and acute lymphocytic leukemia (ALL, n=15), mean FPA levels in patients with active signs and symptoms were significantly higher (AML: 13.5 ng/ml, APL: 20.8 ng/ml, ALL: 12.4 ng/ml) than those examined during remission states (AML: 7.7 ng/ml, P less than 0.02, APL: 3.9 ng/ml, P less than 0.01, ALL: 2.7 ng/ml, P less than 0.01). FPA levels in patients with APL inversely correlated to fbg (r= -0.6399, P less than 0.01). In patients with lung cancer (n=75), mean FPA level in advanced stage (17.7 ng/ml, n=67) were significantly higher than those examined in early stage 6.5 ng/ml, n=8, P less than 0.001). In patients with acute disseminated intravascular coagulation (n=12), prolonged prothrombin time and activated partial thromboplastin time, severely reduced fbg and platelets, and remarkably elevated fibrin degradation product were found. Elevated FPA and beta-TG levels were also found (FPA: 23.5 +/- 15.0 ng/ml, beta-TG: 100.0 +/- 63.0 ng/ml). In five patients with thrombotic diseases who were treated successfully with 12500 IU of heparin per 12 hours (subcutaneous injection), plasma FPA levels were reduced to near normal levels quicker than changes of other indicators. These clinical and experimental data suggested that FPA was an useful indicator for active coagulation process.