Abstract W P58: Thromboelastography Can Detect the Anticoagulant Effect of Factor Xa Inhibitors in Patients Who Might Be Eligible for Tissue Plasminogen Activator Treatment for Acute Ischemic Stroke
Background: Factor Xa inhibitors are approved for stroke prevention in patients with atrial fibrillation. The management of such patients is challenging if they are candidates for intravenous tPA since there is no rapidly available test to detect their anticoagulant effect. Thromboelastography (TEG) analyzes the dynamics of coagulation (Figure 1) and has previously demonstrated a hypercoagulable state in acute stroke patients. We sought to determine whether TEG can detect the anticoagulation effect of Factor Xa inhibitors in stroke patients.
Methods: Venous blood from seven subacute cardioembolic stroke patients prescribed Rivaroxaban was analyzed before (baseline) and 2, 4, 6 hours after drug administration with four patients also analyzed at 18 hours. Comparison of TEG parameters at various time intervals were assessed by repeated measures analysis of variance. Generalized Estimating Equations with an autoregressive correlation matrix was applied to account for the correlation within patients.
Results: Baseline TEG results required approximately 11 minutes to obtain. Higher R values were seen from baseline upto 18 hours, along with increased K values lasting upto 6 hours. Lower G, MA, and alpha-angle values were seen from baseline till 4 hours (Table 2). Together these results indicate slower and less strong clotting, and that the anti-coagulation effects of the drug peak at about 4-6 hours, with a trend towards normalization by 18 hours.
Conclusion: TEG can detect the anticoagulant effect of Factor Xa inhibitors in stroke patients, and might be useful for guiding emergency management of those eligible for tPA.
Author Disclosures: R. Bowry: None. S. Fraser: None. J.M. Archeval-Lao: None. S.A. Parker: None. C. Cai: None. M.H. Rahbar: None. J.C. Grotta: None.
- © 2014 by American Heart Association, Inc.