Lepirudin dose-dependently increases thrombelastography parameters at therapeutic plasma concentrations as measured with ROTEM® - a pilot study

Background: The aim of this in-vitro pilot study was to assess the usefulness of the thrombelastograph ROTEM (R) for determining the anticoagulant activity of lepirudin. Methods: The ROTEM (R) parameters, clotting-time, clot formation time and maximum clot firmness were measured in the presence of increasing concentrations of lepirudin (10(-4) mu g/ml - 10 mu g/ml). Citrated blood was obtained from 16 healthy male subjects. Results: Clotting-time increased from 79.1 +/- 53.4 s at baseline to 194.1 +/- 151.9 s at a drug concentration of 1 mu g/ml as measured with EXTEM (p < 0.0001). Borderline significance was found for the difference between maximum clot firmness at baseline (60.2 +/- 4.3 mm) and after drug application (55.5 +/- 6.5 mm). Conclusions: This pilot investigation shows that the ROTEM (R) device may be suitable for monitoring lepirudin at low concentrations but the results should be confirmed in a larger study and the ROTEM (R) device validated against standard methods.