Abstract Number: PB1286
Meeting: ISTH 2020 Congress
Background: Newborns during first days after birth have decreased concentration of plasma proteins; yet, their hemostasis is shifted to hypercoagulation detected by global hemostasis assay thrombodinamics, and is represented by increased clot growth rate and spontaneous clotting.
Aims: We aim to identify the causes of the observed neonatal hypercoagulation.
Methods: 22 newborns were enrolled into the study. All parents gave their written informed consent. Cord and peripheral blood was drawn into 106 mM sodium citrate tubes with or without 50 µg/ml corn-trypsin inhibitor (CTI) immediately after birth. Clot growth rate (V) and spontaneous clotting (Tsp) were assessed using thrombodynamics. To find out the origins of hypercoagulation we added either 100 nM of factor VIIa with inhibited active site (FVIIai) to block extrinsic tenase or 100 nM of activated factor IXa inhibitor nitrophorin 2 (NP2) to block intrinsic pathway.
Results: We revealed hypercoagulation both in cord and peripheral blood samples with no significant difference between sample types. In 95% of cord samples spontaneous clotting was observed. CTI had no significant effect on hypercoagulation (Median (25-75%) µm/min: V=49 (40-60) µm/min; V (CTI)=41(39-50) µm/min; the reference range was 20-29 µm/min) or spontaneous clotting (Tsp=26 (19-33) min; Tsp(CTI)=24 (15-37) min; no spontaneous clotting was observed in adult healthy donors). Same tendencies were observed in peripheral blood.
Addition of NP2 slightly shifted hemostasis towards normal coagulation in cord blood (Tsp was prolonged from 24 (16-37) min up to 38 (20-54) min; P=0.004) and had no impact in peripheral blood. Addition of FVIIai dramatically prolonged Tsp both in cord blood (Tsp=24 (16-37) min; Tsp( FVIIai)=60 (43-60) min; P=0.001) and in peripheral blood (Tsp=18 (14-57) min; Tsp(FVIIai)=51 (23-60) min; P=0.001).
Conclusions: Hypercoagulation in newborns is caused by activation of coagulation predominantly via extrinsic pathway.
To cite this abstract in AMA style:Koltsova E, Lipets E, Arutunyan B, Tetruashvili N, Balashova E, Karavaeva A, Balandina A. Coagulation Activation Via Extrinsic Pathway Is the Major Cause of Hypercoagulation in Newborns during First Days of Life [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/coagulation-activation-via-extrinsic-pathway-is-the-major-cause-of-hypercoagulation-in-newborns-during-first-days-of-life/. Accessed January 26, 2022.
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