VPB1348 - Serial Platelet Mapping Can be Used to Define Platelet Hyperactivity Throughout Pregnancy

Background: Hypercoagulability occurs in pregnancy due to increased procoagulant factors and decreased anticoagulant factors. However, less is known about platelet contribution to hypercoagulability and venous thromboembolism (VTE). Platelet mapping (PLM) using thrombelastography (TEG) analysis can be used to activate platelets at the adenosine diphosphate (ADP) receptor or the thromboxane A2 (AA) receptor, to evaluate clot strength. By using PLM to identify the platelet contribution to hypercoagulability in pregnancy, we can better understand the mechanism of pregnancy-related VTE.

Aims: To evaluate platelet contribution to hypercoagulability during healthy pregnancy and to use PLM analysis to assess aspirin use.

Methods: Following ethics approval, eligible pregnant women who provided informed consent were enrolled in a single centre, prospective cohort and were followed serially with TEG whole-blood analysis monthly during the first and second trimester, and every two weeks during the third trimester. Platelet hyperactivity was defined as an ADP and AA maximal amplitude value (MA; a measure of clot strength) ≥55mm. Mean MA values were calculated at each timepoint to measure the duration of hypercoagulability. Descriptive statistics were used.

Results: Seven consecutive participants were enrolled (mean age=32±2.7 years). TEG-defined hypercoagulability increased throughout pregnancy (Figure 1). Platelet hyperactivity was identified in both the ADP and AA pathways, and increased throughout pregnancy (Figure 1). The AA-MA values for a single participant taking aspirin (162 mg) daily were above 55 mm for the majority of her pregnancy, suggesting platelet hyperactivity (Figure 2).

Conclusion(s): This study identified that platelet-mediated hypercoagulability begins early in pregnancy and increases as pregnancy progresses. The data suggests that further analysis is needed to better understand the role of aspirin and platelet contribution in hypercoagulability. Further investigation is needed to determine if point-of-care TEG-analysis can identify platelet hyperactivity in pregnant women at risk for VTE.