The aim of the Perioperative Anticoagulant Use for Surgery Evaluation (PAUSE) Study, is to establish a safe, standardized protocol for the perioperative management of patients with atrial fibrillation (AF) who are receiving a novel oral anticoagulant (DOAC) drug, either dabigatran, rivaroxaban or apixaban, and require an elective surgery/procedure.

The primary aim is to demonstrate that a standardized but patient-focused protocol for the perioperative management of each DOAC is safe, with acceptably low rates of perioperative major bleeding (MB) and arterial thromboembolism (ATE). The perioperative protocol is adjusted based on patient renal function and surgery/procedure-related bleed risk, to optimize patient safety, and does not involve heparin bridging anticoagulation.

The secondary aim of the PAUSE Study is to determine the effect of the pre-operative DOAC interruption protocol on the level of residual anticoagulation, when measured by 'everyday' coagulation tests that are not DOAC-specific (e.g., activated partial thromboplastin time [aPTT]) and 'specialized' coagulation tests that are DOAC-specific (dilute thrombin time [TT] - HemoclotTM, and anti-factor Xa assays).

Approximately 3,300 patients from 15 to 25 centres over a 3.5 year period will be recruited across Canada for the PAUSE Study.

Patients with Atrial Fibrillation and are currently taking dabigatran, rivaroxaban and apixaban (DOACs) and require elective surgery/procedure will follow a standardized management perioperative protocol for discontinuation of their DOAC prior to surgery. Patients will be discontinuing the DOAC they are currently receiving from 1 to 4 days prior to surgery or procedure, depending on bleed risk, type of DOAC, and creatinine clearance rate.

A blood sample will be taken on the day of the surgery or procedure for measurement of laboratory outcomes (residual level of anticoagulant on day of surgery).

Patients will be followed up weekly up to a month for primary outcome assessments.

Inclusion Criteria:

1. Age 18 years or older
2. Receiving a DOAC (dabigatran or rivaroxaban or apixaban) for Atrial Fibrillation
3. Ability to assess patient at lease one day prior to DOAC discontinuation

Exclusion Criteria:

1. CrCl less than 30 mL per min for dabigatran- and rivaroxaban-treated patients ( less than 25 mL per min for apixaban-treated patients) as estimated by Cockroft-Gault formula
2. Cognitive impairment or psychiatric illness that precludes collection of followup data
3. Inability or unwillingness to provide informed consent

Those patients who are currently taking dabigatran, rivaroxaban or apixaban for oral anticoagulation used for stroke prevention in atrial fibrillation, and who require its temporary interruption for a surgical or other procedure, will be recruited from 15 to 25 participating sites across Canada.

The study plans to screen 4,114 patients over a 3 year period, with 80 per cent expected enrollment (3,291 patients) from 16 sites across Canada. Equal number of patients, per oral anticoagulant arm will be enrolled, with approximately 1,000 patients taking each DOAC.