Establishing a reference range for thromboelastography maximum amplitude in patients administrating with antiplatelet drugs

OBJECTIVE: We aimed to establish the reference range of thromboelastograph (TEG) maximum amplitude (MA) in patients taking antiplatelet drugs. METHODS: Between August 2015 and July 2018, a total of 4614 patients administrating with antiplatelet drugs (clopidogrel and aspirin) were retrospectively analyzed in this study. For MA(A) parameter, we used the 10th and 90th percentiles to establish a reference range. The Spearman correlation was used for the correlation analysis among the inhibition rate of adenosine diphosphate (ADP%) and MA(ADP), inhibition rate of arachidonic acid (AA%) and MA(AA). Then, through receiver operating characteristic (ROC) curve analysis of the best cutoff point, the reference ranges of MA(ADP) and MA(AA) could be deduced. Consistency evaluation was performed by statistical analysis of ADP% and MA(ADP), AA% and MA(AA) pairing for 4459 patients. RESULTS: The reference range of MA(A) was 8.1‐25.8 mm. The reference range of MA(ADP) was 19.8‐43.2 mm, and the corresponding sensitivity of two endpoints was 0.796, 0.856 and specificity were 0.897, 0.904, respectively. The reference range of MA(AA) was 18.9‐37.7 mm, and the corresponding sensitivity of two endpoints was 0.819, 0.829 and specificity were 0.922, 0.896, respectively. The inconsistency rate of ADP% and MA(ADP), and AA% and MA(AA) was 20.1% (898 cases) and 16.6% (738 cases), respectively. CONCLUSIONS: The reference range of MA(ADP) and MA(AA) established by us were better in sensitivity and specificity. MA(ADP) and MA(AA) were more accurate than conventional inhibition rate analysis in guidance of antiplatelet therapy, especially in patients with excessive low MA or high MA(A).