Viscoelastometry for detecting oral anticoagulants.

BACKGROUND

Determination of anticoagulant therapy is of pronounced interest in emergency situations. However, routine tests do not provide sufficient insight. This study was performed to investigate the impact of anticoagulants on the results of viscoelastometric assays using the ClotPro device.

METHODS

This prospective, observational study was conducted in patients receiving dabigatran, factor Xa (FXa)-inhibitors, phenprocoumon, low molecular weight heparin (LMWH) or unfractionated heparin (UFH) (local ethics committee approval number: 17-525-4). Healthy volunteers served as controls. Viscoelastometric assays were performed, including the extrinsic test (EX-test), intrinsic test (IN-test) Russel's viper venom test (RVV-test), ecarin test (ECA-test), and the tissue plasminogen activator test (TPA-test).

RESULTS

70 patients and 10 healthy volunteers were recruited. Clotting time in the EX-test (CT) was significantly prolonged versus controls by dabigatran, FXa inhibitors and phenprocoumon. CT was prolonged by dabigatran, FXa inhibitors and UFH. Dabigatran, FXa inhibitors and UFH significantly prolonged CT in comparison with controls (median 200, 207 and 289 vs 63 s, respectively; all p < 0.0005). Only dabigatran elicited a significant increase in CT compared to controls (median 307 vs 73 s; p < 0.0001). CT correlated strongly with dabigatran plasma concentration (measured by anti-IIa activity; r = 0.9970; p < 0.0001) and provided 100% sensitivity and 100% specificity for detecting dabigatran. Plasma concentrations (anti-XA activity) of FXa inhibitors correlated with CT (r = 0.7998; p < 0.0001), and CT provided 83% sensitivity and 64% specificity for detecting FXa inhibitors.

CONCLUSIONS

In emergency situations, ClotPro viscoelastometric assessment of whole-blood samples may help towards determining the presence and type of anticoagulant class that a patient is taking.

TRIAL REGISTRATION

German clinical trials database ID: DRKS00015302 .