Point-of-care testing for emergency assessment of coagulation in patients treated with direct oral anticoagulants

Critical Care 2017;21:32 doi:10.1186/s13054-017-1619-z

Presented by: Dr B Eagle

Background

  • The use of direct oral anticoagulants (DOAC) is increasing, yet there is no way to point of care test coagulation in patients taking these drugs.
  • Haemochron signature is a coagulation point of care test (POCT) that is sensitive to rivaroxaban and dabigatran, although its action on apixiban is unreported.
  • This study aims to evaluate the use of haemochron in guiding emergency treatment of DOAC treated patients.

Design & Setting

  • Prospective observational single centre study based in Tubingen Germany.
  • Patients enrolled receiving first dose of apixiban, rivaroxaban or dabigatran.
  • Patients excluded with any form coagulopathy or on other anticoagulants.
  • 60 patients enrolled.
  • Samples of blood taken from each subject before DOAC intake and at intervals up to 24 hours post ingestion.
  • Bedside POCT testing using Haemochron was undertaken – PT/INR, aPTT, ACT.
  • Lab anti 10a concentrations were measured and liquid chromatography with mass spec used to determine concentrations as a gold standard.
  • Analyses used to determine whether POCT can determine concentrations considered safe for emergency surgery and for stroke thrombolysis i.e. POCT PT of 1 equates to concentration of 30ng/ml for rivaroxban – considered the safe threshold for operations.

Results

  • Correlation between POCT and apixiban concentrations were weak for PT/INR and moderate for ACT.
  • No correlation for aPTT.
  • Rivaroxaban correlation strong for PT/INR and ACT and weak for aPTT.
  • Dabigatran correlated strongly with all assays.

Conclusions

  • Hemochron POCT testing correlates with rivaroxaban and dabigatran concentrations but not apixiban concentrations.
  • POCT specific cut offs can be used to exclude rivaroxaban concentrations at the bedside with high specificity.

Strengths

  • Good sample numbers
  • Novel idea, to help with a clinically relevant problem

Weaknesses

  • Essentially a lab study – using whole blood – tests not been used to actually guide any clinical intervention
  • This study does not help to determine what the clinically relevant concentrations of these drugs are – even though it can test for arbitrarily determined levels
  • Study does not discuss how Haemochron differs in effectiveness from established POC testing such as TEG or ROTEM

Implications & Potential for Impact

  • Haemochron signature could be used to rule out relevant concentrations of rivaroxaban and dabigatran.
  • May allow concentration based cut offs for operating on patients on DOACS to be used rather than time based cut offs currently used – time based estimation may be very variable