Fibrinolysis after an Elective Caesarean Section without Postpartum Hemorrhage: Pilot Study for Reference Values from the Simultaneous Thrombin and Plasmin Generation Assays

Abstract

ntroduction: Postpartum Hemorrhage (PPH)-induced coagulopathy should be better explored. An innovative Simultaneous Generation of Thrombin and Plasmin Assay (SGTPA) was developed. Objective: To establish postpartum SGTPA references. Methods: Blood samples collected immediately after delivery (T0) and then 30, 60, 120 and 360 minutes later. Thrombin Generation (TG) and Plasmin Generation (PG) changes over time analyzed in 51 women after elective cesarean section without PPH and compared with Non-Pregnant (NP) women. The SGTPA variables’ correlations with fibrinogen levels, D-dimer levels and physiological blood loss were assessed in a mixed model. Results: 37 women were included. TG and PG were higher in the postpartum group than in the NP group. TG increased early and then remained stable (baseline TG Area Under the Curve (AUC) [95% Confidence Interval (CI)] = 41037 [36850-43537] nM.min). The fibrinogen level varied over time, along with TG (p<0.001). Plasmin generation increased from 30 to 120 minutes (AUC [95% CI]: 2104 [1437; 2613] nM.min), along with a change in the D-dimer level (p=0.018). The time to the plasmin peak and the time interval between the TG and PG peaks showed the greatest inter-individual variability at T0 and were associated with physiological volumes of blood loss during cesarean delivery. Conclusion: Reference SGTPA postpartum range was established. The SGTPA appears to be valuable for measuring TG and PG. TG and coagulation activation increased immediately after delivery, whereas PG and fibrinolysis increased later.