Poster Presentation Society of Obstetric Medicine of Australia and New Zealand ASM 2018

Evaluation of haemostasis in pregnancy using novel global coagulation assays (#77)

Johnathan Tham 1 2 3 , Hui Yin Lim 1 3 4 , Prahlad Ho 1 , Lisa Hui 2 3 , Vanessa Manitta 1 , Gene-Lyn Ngian 2
  1. Department of Haematology, Northern Health, Melbourne, Victoria, Australia
  2. Department of Obstetrics & Gynaecology, Northern Health, Melbourne, Victoria, Australia
  3. University of Melbourne, Melbourne, Victoria, Australia
  4. Australian Centre for Blood Diseases, Melbourne, Victoria, Australia

Introduction: Pregnant women are at an increased risk of venous thromboembolism (VTE). Routine laboratory tests are inadequate in evaluating overall haemostasis. The Global Coagulation Assays (GCA) including thromboelastography (TEG), thrombin generation using the calibrated automated thrombogram (CAT), and fibrin generation using the overall haemostatic potential (OHP) assay, may provide a more holistic assessment of the coagulation pathway.

Aim: We aimed to evaluate the use of GCA in the assessment of pregnant women at term gestation.

Method: Pregnant patients at 38-41 weeks’ gestation were recruited prior to elective Caesarean section (not in labour). Bloods were collected at a single preoperative timepoint for baseline routine tests and research samples, which included citrated kaolin whole blood for TEG and platelet poor plasma for thrombin and fibrin generation assays. The results were compared to previously collected nonpregnant healthy female controls aged 18 to 45 years (n=31). Statistical analysis was performed in SPSS using the Shapiro-Wilk, independent t-test and Mann-Whitney tests.

Results: Nineteen women (median age 31 years) were recruited. All had singleton pregnancies and all but one was multiparous. Four patients (21%) had gestational diabetes and 79% (n=15) had a body mass index (BMI) >30 kg/m2 at the time of delivery. There was significant differences between the pregnant and non-pregnant women in all three GCAs. Pregnant patients were more hypercoagulable on TEG with significantly increased maximum amplitude and α-angle as well as reduced lysis 30. CAT demonstrated elevated endogenous thrombin potential and thrombin peak with no significant difference in velocity index. There was a trend towards higher endogenous thrombin potential with increasing BMI (p=0.06). The overall coagulation potential and overall hemostatic potential were both significantly increased in the pregnant population.

Conclusion: GCA can be used to delineate the hypercoagulable state in pregnant women. The additional contribution of BMI to hypercoagulability in the pregnant population may also be detectable by GCA and warrants further study.

Table 1: Comparison between pregnant vs normal control for GCA