Comparison of two laboratory methods for thrombin generation in pregnancy with high risk for thrombosis
M. Schwethelm, M. Martinez, I. Hoesli, D. Tsakiris (Basel, Switzerland)
Women issues in thrombosis and hemostasis
Time: 17:15 - 18:15
Objective: Pregnancy and delivery are high-risk conditions for thrombotic complications. Women with heritable thrombophilia with or without thromboembolism in their medical history are at additional higher risk to develop thrombosis and are normally followed-up during pregnancy for evaluation of the prothrombotic state. Follow-up is done by clinical evaluation and sometimes it includes biological markers of activation of coagulation. A disproportional increase would theoretically predict high risk for thrombotic events but usefulness of these markers has not been validated in an evidence-based setting. Aims of this study were: a) to describe changes of biological markers of coagulation activation and thrombin generation in each trimester of pregnancy, b) to compare two different methods for assessment of thrombin generation, c) to check whether heparin prophylaxis in the third trimester affects thrombin generation.
Methods: Data on file of 102 consecutive pregnancies with hereditary thrombophilia or thrombosis were retrospectively analyzed. Pregnant women were routinely followed every 4-6 weeks for thrombotic complications during pregnancy. Any thrombotic event or preeclampsia or premature delivery were recorded. Thrombin-Antithrombin-Complex (TAT), D-Dimers (DD) and endogenous thrombin potential (ETP) by a functional chromogenic assay (CAT, calibrated automated thrombogram) were assayed routinely once in the middle of each trimester using standard methods.
Results: TAT (4.3+2.9, 6.4+5.2, 7.7+4.3 microg/L) and DD (0.9+1.5, 1.6+2.1, 2.0+2.3 microg/ml) were increased slightly but continuously and statistically significantly from each trimester to the other. Women receiving heparin prophylaxis showed the same pattern and did not differ from the whole cohort. CAT did not show any differences between trimesters. Women in third trimester with or without heparin prophylaxis did not differ with respect to DD (2.0+2.6 vs. 2.0+1.7 microg/ml), TAT (7.5+2.9 vs. 8.2+5.9 microg/L), CAT-ETP (1696+962 vs. 1715+804 AU).
Conclusion: TAT and DD were elevated as pregnancy progressed, as expected. CAT-ETP in addition to TAT does not add any value of information. TAT and DD do not add any safe value of information with respect to the effect of heparin prophylaxis and they might not be needed as isolated observation tools.