Our research Research collaborations PBI Anticoagulant Reversal and Events Study (ARES) Collaborative ARES Collaborative Synopsis Objectives 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. Partners 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 Thrombosis & Haemostasis Society of Australia and New Zealand Asia Pacific Society on Thrombosis and Haemostasis