Recommendation 1 - Decision considerations (2014)
We recommend that in a patient with AF or atrial flutter, a decision to interrupt antithrombotic therapy for an invasive procedure must balance the risks of a thromboembolic event (as indicated by a higher CHADS2 score, mechanical heart valve, or rheumatic heart disease) with those of a bleeding event (as indicated by a higher HASBLED score and procedures with higher bleeding risks) (Strong Recommendation, Low Quality Evidence).

Recommendation 2 – OAC interruption not necessary for most lower risk procedures (2016, updated from 2014)
We suggest that interruption of anticoagulant therapy, particularly for vitamin K antagonists, in a patient with AF/AFL is not necessary for most procedures with a low risk of bleeding, such as cardiac device implantation (pacemaker or implantable defibrillator), and most dental procedures (Table 1) (Conditional Recommendation, Moderate Quality Evidence).

Recommendation 3 – OAC interruption of anticoagulant therapy for medium to high risk procedures (2014)
We recommend that interruption of anticoagulant therapy in a patient with AF or AFL will be necessary for most procedures with an intermediate or high risk of major bleeding (see Table 1) (Strong Recommendation, Low Quality Evidence).

Values and preferences (2014)
Practitioners responsible for preventing thromboembolic events in patients with AF/AFL and practitioners responsible for preventing peri-procedural bleeding each tend to over-value their unique roles. Recommendations 1-3 are intended to promote a balanced approach to minimizing the combined outcome of peri-procedural thromboembolic events and major bleeding.

Recommendation 4 - Aspirin or clopidogrel interruption 5-7 days prior to procedure (2016, updated from 2014)
When a decision to interrupt aspirin or clopidogrel (or other ADP receptor/P2Y12 inhibitors including prasugrel, ticagrelor), therapy for an invasive procedure has been made for a patient with AF/AFL, we suggest that interruption begin 5-7 days before the procedure, except for procedures with a very high risk of bleeding, in which case we suggest interruption 7-10 days before the procedure (Conditional Recommendation, Low Quality Evidence).

Recommendation 5 - Warfarin interruption 5 days prior to procedure (2014)
When a decision to interrupt warfarin therapy for an invasive procedure has been made for a patient with AF or AFL, we suggest that the interruption begin 5 days prior to the procedure and that a procedure with a low bleeding risk may proceed when the INR is <1.5 and a procedure with an intermediate or high bleeding risk may proceed when the INR is <1.2 (Conditional Recommendation, Low Quality Evidence).

Recommendation 6 – Stop apixaban or rivaroxaban 1-2 days pre-low risk; 2-3 days pre-medium or high-risk procedure (2014)
When a decision to interrupt apixaban or rivaroxaban therapy for an invasive procedure has been made for a patient with AF or AFL, we suggest that the interruption begin 1-2 days prior to the day of a procedure with a low risk of major bleeding and 2-3 days prior to the day of a procedure with an intermediate or high risk of major bleeding (Conditional Recommendation, Low Quality Evidence).
* Note: Edoxaban was not approved at the time of the issuance of the recommendation in 2014. The information present in this recommendation also applies to Edoxaban.

Recommendation 7 – Stop dabigatran 1-2 days prior pre-low risk; 2-3 days pre-medium or high-risk procedure, depending on renal function (2014)
When a decision to interrupt dabigatran therapy for an invasive procedure has been made for a patient with AF or AFL, we suggest that the interruption begin 1-2 days before a procedure with low risk of major bleeding and 2-3 days before a procedure with an intermediate or high risk of major bleeding for CrCl is ≥80mL/min (Conditional Recommendation, Low Quality Evidence). The upper end of these ranges should be used if CrCl is 50-80 mL/min, an additional day should be added for CrCl 30-50 mL/min, and in case CrCl is found to be <30 mL/min, yet one more day of dabigatran withdrawal should be added (Conditional Recommendation, Low Quality Evidence).

Recommendation 8 - Bridging therapy in a patient at high risk of thromboembolic events (2016, updated from 2014)
When a decision to interrupt warfarin-therapy for an invasive procedure has been made for a patient with AF/AFL, we suggest that bridging therapy with LMWH or UFH be instituted when the INR is below therapeutic level only in patients at high risk of thromboembolic events (CHADS2 ≥4, mechanical heart valve, stroke/TIA within 3 months, rheumatic heart disease) (Conditional Recommendation, Low Quality Evidence).

Recommendation 9 – No bridging for patients on NOAC for procedures requiring interruption of anticoagulation (2016)
We recommend no bridging (LMWH or UFH) for NVAF patients on NOAC undergoing elective surgery or invasive procedures requiring interruption of anticoagulation (Strong recommendation, Moderate Evidence).

Practical tip (2016)
Duration of pre-procedural interruption of NOACs should be adjusted according to renal function (see supplementary appendix, part 11, recommendations 6-7). The Thrombosis Canada Perioperative Anticoagulant Management Algorithm is a helpful tool to aid decisions regarding peri-procedural anticoagulation. http://thrombosiscanada.ca/?page_id=502&calc=perioperativeAnticoagulantAlgorithm

Recommendation 10 - Heparin bridging pre-procedure (2016, updated from 2014)
We recommend that when LMWH or UFH bridging is used for an invasive procedure such therapy be started prior to the procedure when the INR is below the therapeutic level and be stopped 24 hours prior to the procedure for LMWH and 4-6 hours prior to the procedure for UFH (Strong recommendation, Low Quality Evidence).

Recommendation 11 – Heparin bridging post-procedure (2016, updated from 2014)
When LMWH or UFH bridging is used for an invasive procedure, we suggest that such therapy be restarted after the procedure when hemostasis is established (usually 24 hours for a procedure with a low risk of bleeding and 48-72 hours for a procedure with an intermediate or high risk of bleeding) in prophylactic dosages for the first 24 to 72 hours and then increased to therapeutic dosages. Bridging is then continued until INR is in the therapeutic range (Conditional Recommendation, Low Quality Evidence).

Recommendation 12 – Warfarin, ASA, clopidogrel restarted when hemostasis is established (2014)
When warfarin, ASA, or clopidogrel therapy has been interrupted for an invasive procedure we suggest that such therapy be restarted after the procedure when hemostasis is established (usually 24-48 hours for a procedure with a low risk of bleeding and 48-72 hours for a procedure with an intermediate or high risk of bleeding) (Conditional Recommendation, Low Quality Evidence).

Recommendation 13 – NOAC restarted one day after hemostasis is established (2014)
When apixaban, dabigatran, or rivaroxaban therapy has been withdrawn for an invasive procedure we suggest that such therapy be restarted after the procedure one day after hemostasis is established (usually 48 hours for a procedure with a low risk of bleeding and 72 hours for a procedure with an intermediate or high risk of bleeding) (Conditional Recommendation, Low Quality Evidence).

Values and preferences (2016, updated from 2014)
All of these peri-procedural recommendations assume that the practitioner has weighed an individual patient’s risks of thromboembolic events and of experiencing a major bleeding event in the peri-procedural period as discussed in the previous section and has elected to interrupt antithrombotic therapy. These recommendations are then intended to summarize how the goal of interrupted therapy can be achieved, with high value placed on achieving that goal just before the procedure is performed. Recommendations regarding heparin bridging place a higher value on prevention of stroke and systemic thromboembolism in patients at high risk than on the inconvenience and higher risk of major bleeding associated with heparin bridging. Recommendations regarding the timing of post-procedural re-introduction of antithrombotic therapy are intended to promote a balanced approach to minimizing the combined outcome of post-procedural thromboembolic events and major bleeding.