Effective Prophylaxis of Thrombosis by Antithrombin III Concentrate in a Pregnant Woman with Congenital Antithrombin III Deficiency: Relations between Plasma Antithrombin III Activity and the Plasma Levels of Hemostatic Molecular Markers

Abstract

The value of antithrombin III (AT III) concentrate and a standard criterion for its use were examined in a pregnant woman with congenital AT III deficiency by continuous monitoring of plasma AT III activity and the plasma levels of hemostatic molecular markers. The rates of improvement of various markers after AT III administration (frequency of improvement/frequency of administration) were as follows: fibrinopeptide A (FPA) 82%, D-dimer 70%, fibrinopeptide B beta 15-42 73%, beta-thromboglobulin 60%, and platelet factor 4 50%. There was no significant correlation between the plasma AT III activity and all plasma FPA values, but FPA values of over 3.9 ng/ml showed a significant negative correlation with AT III activity: AT III activity (%) = -6.59 x FPA (ng/ml) + 125, r = -0.851, p less than 0.02. We therefore recommend continuous monitoring of the plasma FPA level and administration of AT III concentrate when the FPA level is elevated. According to the regression line shown above, plasma AT III activity should be raised to 100% to keep the FPA level below 6.0 ng/ml with 95% confidence limit.