ARES Collaborative Synopsis

  • To document the current practice in major centres in Australia and New Zealand for achieving haemostasis in patients who present with significant haemorrhage or urgent surgery whilst on new (dabigatran, rivaroxaban, apixaban or endoxaban) or established (warfarin) oral anticoagulants; and
  • To determine the circumstances and level of anticoagulation of patients who present with embolism whilst on oral anticoagulants at the time of presentation.

Design and outcomes

The ARES Collaborative is an observational prospective study of consecutive patients who present with bleeding and thromboembolism to emergency departments and are taking the new oral anticoagulants (NOAC- dabigatran, rivaroxaban, apixaban or endoxaban) or warfarin therapy. The clinical circumstances and severity of the event will be recorded, and the management strategies observed for urgent anticoagulant reversal or treatment of thromboembolism.

Outcome measures will include:

  • Routine laboratory measurements;
  • Type of reversal agent used for haemorrhage (Prothrombinex-VF, rFVIIa, FEIBA);
  • Blood product use (Fresh Frozen Plasma, Cryoprecipitate, Packed Red Cells, Whole Blood);
  • Other haemostatic agents (Tranexamic acid, vitamin K);
  • Other measures (activated charcoal, haemodialysis, surgery);
  • Management of thromboembolism;
  • Subjective haemostatic assessment of response; and
  • Clinical outcome at 30 days.

Interventions and duration

As ARES Collaborative is an observational study to document the current standard of care in Australia and New Zealand, there will be no change to the current management of the patient presenting with anticoagulant related bleeding or thrombosis. The study duration is 36 months.

Sample size and population

Up to 2000 patients on NOACs or warfarin presenting with either significant haemorrhage, urgent surgery requiring OAC reversal or thromboembolism.


  • Monash University, VIC
  • Sydney University, NSW
  • Hollywood Private Hospital, WA
  • Sir Charles Gardiner Hospital, WA
  • Royal Adelaide Hospital, SA
  • The Alfred Hospital, VIC
  • Monash Medical Centre, VIC
  • Geelong Hospital, VIC
  • Austin Health, VIC
  • The Canberra Hospital, ACT
  • Prince of Wales Hospital, NSW
  • St Vincents Hospital, NSW
  • Royal North Shore Hospital, NSW
  • Calvary Mater Newcastle, NSW
  • Westmead Hospital, NSW
  • Concord Hospital, NSW
  • Princess Alexandra Hospital, QLD
  • Royal Brisbane and Women’s Hospital, QLD
  • Canterbury District Health Board, Canterburry NZ
  • Northshore Hospital Waitemata District Health Board, Waitemata NZ

Supporting organisations