Thromboelastography With Platelet Mapping is Not an Effective Measure of Platelet Inhibition in Patients With...

Thromboelastography with platelet mapping (TEG-PM) is a modality to measure platelet function, especially in patients taking antiplatelet medications. It consists of two components: arachidonic acid (AA), which is sensitive to aspirin, and adenosine diphosphate (ADP), which is sensitive to clopidogrel. In patients with spontaneous intracerebral hemorrhages (sICH), the clinical interpretation of platelet mapping is unclear. The objective of this study was to evaluate TEG-PM in patients with sICH on aspirin and/or clopidogrel who receive platelet transfusions. This study was an IRB-approved, retrospective case-control study over three years at an academic medical center. Adult patients with sICH were included if they had an admission computed tomography head (CTH) and platelet mapping followed by a repeat platelet mapping and CTH post platelet transfusion. A threshold of 50% inhibition was used as the benchmark for both ADP and AA inhibition. Around 248 subjects with sICH were identified, and 107 were excluded for incomplete documentation, leaving 141 for analysis. Of these, nine met our inclusion criteria. No statistical significance was found on the antithrombotic effects of aspirin or clopidogrel on TEG-PM (p=1.00 for both). Sensitivity and specificity of TEG-PM for clopidogrel was 100% and 42.9%, respectively, and 80% and 0%, respectively, for aspirin. Platelet transfusion did not significantly change AA or ADP inhibition (p=1.00). Hemorrhagic expansion on CTH was not associated with a decrease AA or ADP inhibition (p=1.00). TEG-PM is not an effective measure of platelet inhibition in sICH patients who were on antiplatelet medications and is not a reliable measurement following platelet transfusion.