title: Point-of-care ecarin clotting time versus activated clotting time in correlation with bivalirudin concentration.
abstract: BACKGROUND
  A thrombin inhibitor management (TIM) point-of-care test based upon the ecarin clotting time (ECT) has been developed. The ECT has been suggested to more accurately reflect the anti-coagulant effect of direct thrombin inhibitors compared with the activated clotting time (ACT). We sought to examine the correlation of the TIM-ECT test with bivalirudin concentration in patients undergoing percutaneous coronary intervention (PCI), and to compare the performance of this test with the current standard (i.e., ACT).
  
  
  METHODS
  In a multicenter study, blood samples were obtained at six pre-defined time-points in 170 consecutive patients undergoing PCI using bivalirudin. For each sample, the TIM-ECT (citrated and non-citrated), ACT, and bivalirudin concentration was determined.
  
  
  RESULTS
  Considering samples from all time-points (n=784), the correlations of TIM-ECT citrated, TIM-ECT non-citrated, and ACT with bivalirudin concentration were 0.96, 0.93, and 0.90, respectively. For samples collected at therapeutic levels of bivalirudin (n=353), the correlations of TIM-ECT citrated, TIM-ECT non-citrated, and ACT with bivalirudin concentration were lower, and showed a greater disparity between methods, with correlation coefficients of 0.75, 0.59, and 0.37, respectively. Prediction models based on the measured bivalirudin concentration were developed for TIM-ECT and ACT, and the coefficients of determination (r(2)) of actual versus predicted TIM-ECT and ACT were 0.91 and 0.81, respectively.
  
  
  CONCLUSIONS
  In this PCI population, the TIM-ECT point-of-care test and ACT demonstrated a strong correlation with bivalirudin concentration. The TIM-ECT test had a higher correlation with bivalirudin concentration at therapeutic levels of the drug, and for individual samples appears to more consistently reflect the bivalirudin concentration compared with the ACT.
authors.affiliation: Department of Cardiovascular Disease, Cleveland Clinic Foundation, Cleveland, OH, USA.
authors.forename: Ivan P
authors.initials: IP
authors.lastname: Casserly
authors.forename: Dean J
authors.initials: DJ
authors.lastname: Kereiakes
authors.forename: William A
authors.initials: WA
authors.lastname: Gray
authors.forename: Paul H
authors.initials: PH
authors.lastname: Gibson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Lauer
authors.forename: Joel P
authors.initials: JP
authors.lastname: Reginelli
authors.forename: David J
authors.initials: DJ
authors.lastname: Moliterno
mesh_terms: D000368:Aged; D001780:Blood Coagulation Tests / Q000379:methods* / Q000592:standards; D019343:Citric Acid; D016903:Drug Monitoring / Q000379:methods* / Q000592:standards; D010450:Endopeptidases; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006629:Hirudins / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D006801:Humans; D008297:Male; D010446:Peptide Fragments / Q000008:administration & dosage*; D019095:Point-of-Care Systems; D011994:Recombinant Proteins / Q000008:administration & dosage*
chemical_list: D005343:Fibrinolytic Agents; D006629:Hirudins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D019343:Citric Acid; D010450:Endopeptidases; C020097:ecarin; C074619:bivalirudin