Journal of Thrombosis and Thrombolysis

, Volume 12, Issue 2, pp 165–169

Ecarin Clotting Time but not aPTT Correlates with PEG-Hirudin Plasma Activity

  • Martin Moser MD
  • Johannes Ruef MD
  • Karlheinz Peter MD
  • Benedikt Kohler MD
  • Dietrich C. Gulba MD
  • Natascha Paterna MD
  • Thomas Nordt MD
  • Wolfgang Ku¨bler MD
  • Christoph Bode MD
Article

Abstract

Background: Novel antithrombotic agents such as hirudin have shown promise in the therapy of acute coronary syndromes. PEG-hirudin (polyethyleneglycol conjugated hirudin) has been developed to provide a longer plasma half-life and more stable antithrombotic plasma levels. Privious trials indicated a narrow therapeutic window for hirudin and a number of aPTT (activated partial thromboplastin time)-monitored trials investigating hirudin in acute coronary syndromes had to be stopped because of intracranial bleeding complications.

Objectives: The present study evaluates the ecarin clotting time (ECT), a parameter based on the conversion of prothrombin by the snake venom enzyme ecarin, for the monitoring of PEG-hirudin therapy.

Methods: Plasma from either healthy volunteers (n=20) or from patients (n=10) suffering from unstable angina pectoris (UAP) was spiked with increasing PEG-hirudin concentrations. In a prospective randomized clinical trial patients with UAP were treated with intravenous PEG-hirudin or heparin over 72 hours. Patients were randomized to the following treatment groups: (1) heparin control group, n=15; (2) PEG-hirudin low dose (0.1[emsp4 ]mg/kg bolus, 0.01[emsp4 ]mg/kg/h infusion), n=19; (3) intermediate dose (0.15[emsp4 ]mg/kg and 0.015[emsp4 ]mg/kg/h), n=17; 4) high-dose (0.2[emsp4 ]mg/kg and 0.02[emsp4 ]mg/kg/h), n=16. Spiked plasma samples and plasma from UAP patients treated with i.v. PEG-hirudin were analyzed for aPTT, ECT, and PEG-hirudin levels.

Results: A linear correlation up to the highest therapeutic concentrations could be observed between PEG-hirudin plasma concentrations and the ECT. This was true for both plasma samples spiked with PEG-hirudin in vitro as well as for samples taken from patients treated with i.v. PEG-hirudin (correlation coefficient 0.9, respect.) In contrast the aPTT did not show a reliable linear correlation to PEG-hirudin concentrations.

Conclusion: Monitoring of PEG-hirudin therapy by ECT may help to avoid inadequate anticoagulation or overdosing. Thus, the safety and efficacy profile of PEG-hirudin therapy is likely to be enhanced by ECT monitoring.

anticoagulation PEG-hirudin ecarin clotting time activated partial thromboplastin time 

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Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Martin Moser MD
    • 1
  • Johannes Ruef MD
    • 1
  • Karlheinz Peter MD
    • 1
  • Benedikt Kohler MD
    • 1
  • Dietrich C. Gulba MD
    • 2
  • Natascha Paterna MD
    • 1
  • Thomas Nordt MD
    • 1
  • Wolfgang Ku¨bler MD
    • 1
  • Christoph Bode MD
    • 1
  1. 1.Dept. of Internal Medicine III (Cardiology)University of HeidelbergGermany
  2. 2.Franz-Volhard Klinik, Charite´BerlinGermany

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