Analysis of Neonatal Hemostatic and Thrombotic Mechanism, and Exploring of the New Therapeutic Approach.

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Neonatal hemoatatic mechanism was studied using thrombelastgram (TEG). In the early neonatal period, the r and k values of TEG in neonatal whole blood shortened and the ma value of TEG enlarged rather than these values in adult's whole blood. This characterized hypercoagulation prophile of TEG in neonate was able to be recreated by the addition of activated coagulation factors, such as thrombin, activated factor VIIa, ADP or epinephrine into normal adult whole blood. One of data, the results of activated factor VIIa, was recently submitted to the journal " Thrombosis and Haemostatic" enclosed in the booklet. And another paper concerning about the relationship between the hyper coagulation and anti-thrombotic drugs was recently subscribed. The bleeding time and coagulation time were almost normal in neonate despite the low function of platelets and the low concentrations of vitamin K dependent coagulation factors in neonate compared with adults. But, in pathological state, the thrombosis is more frequent in neonate than in children after neonate. The knowledge of the haemostatic mechanism is still obscure in neonate. From our recent study, von Willebrand factor (vWF) was relatively high and von Willebrand factor-cleaving protease was low in cord bloods of low birth weight to full term neonate. Furthermore, the higher multimer of vWF was detected. This higher multimer of vWF is more potent in hemostasis. And it may be suggested that it is related to be near normal bleeding time in neonate. We have also studied on the shear dependent platelet aggregation in cord bloods. And the low and high shear stress platelet aggregation were low, this mechanism were analyzed by the recreated blood components and the measurement of ecto-ATP activity. Ecto-ATPase in cord bloods was higher than that in adult blood. It may be suggested that ecto-ATP ase is related to the anti-thrombotic mechanism.