Hirudin monitoring using the TAS ecarin clotting time in patients with heparin-induced thrombocytopenia type II

Objective:To assess the reliability of the TAS/ecarin clotting time (ECT) f or on-line monitoring of r-hirudin in cardiovascular surgery with and witho ut cardiopulmonary bypass (CPB). Design: Samples were spiked with r-hirudin (0 to 5 mu g/mL) and calibration curves constructed. Reproducibility was evaluated by measurement of the sa mple five times at each concentration. The influence of variations in hemat ocrit, plasma factors, and platelet count on the test results was examined. Samples were obtained from patients during cardiovascular surgery with CPB (n = 8), without CPB (n = 3), and from volunteers (n = 5) and compared wit h the laboratory reference tests. All tests were performed in duplicate. Setting: Deutsches Herzzentrum Berlin. Participants:Five healthy volunteers and 11 patients undergoing cardiovascu lar surgery. Interventions: None. Measurements and Main Results: The TAS/ECT showed linearity and reliability to an r-hirudin concentration of 5 mu g/mL and was not influenced (p < 0.0 05) by the varying conditions of the in vitro setup. The correlation to the laboratory method was 0.74 for the CPB group and 0.87 for the non-CPB grou p. Conclusions: The TAS/ECT is a reliable assay for monitoring r-hirudin at th e point of care. With this information, the use of r-hirudin during surgery or angioplasty should become more effective and safer. Copyright (C) 2000 by W.B. Saunders Company.