P5598Multicenter observational trial to evaluate TEG6s oral anticoagulant assay in apixaban- treated patients

Abstract

Background: Detection of anticoagulant effects of NOACs and NOAC classification are important in situations such as trauma, stroke or emergent surgery where a major intervention may increase survival. Currently, no standardized point-of-care test is available to evaluate the anticoagulant effects of apixaban. Aims: The aim of the study was to evaluate the anticoagulant effect of apixaban-treated patients and compare with results obtained from healthy volunteers by using the point-of-care TEG®6s Oral Anticoagulant (OAC) assay. Methods: Healthy volunteers (n=27) and patients on apixaban (n=50) were enrolled across 5 sites. Protocol was approved by site IRBs and informed consent was obtained prior to blood draw. To ensure that a range of drug concentrations were captured, blood samples were obtained at non-trough (< 9hrs) and trough (9-12hrs) levels as indicated from last dose (2.5 or 5.0 mg BID). The viscoelastic OAC assay utilizes human Factor Xa and Ecarin as reagents for AFXA and DTI assays, respectively. Data derived from patients on apixaban were compared against the reference range (based on a separate healthy cohort; n=111) to determine sensitivity and specificity for detection. Results: The majority of patients were prescribed apixaban for atrial fibrillation. Patients had significantly longer Reaction Time (R) by AFXA assay (p < 0.001) but not DTI assay (p=0.55) as compared to healthy volunteers. AFXA-R time >1.9 min indicated detection of anticoagulation effect with 96% sensitivity and 100% specificity (Fig A). A DTI R-time cut-off < 2.3 min classified an anti-Xa with 98% sensitivity (Fig B). There was a large interindividual variability in anticoagulant effect that was not attributable to dose or trough measurements. Conclusions: The automated TEG®6s device with its OAC assay may be an effective tool to rapidly identify anticoagulant effects in apixiban- treated patients and thus, facilitate care in emergent situations.