In this episode, I’ll discuss whether patients taking warfarin for atrial fibrillation require bridging.
Background
For almost 10 years, guidelines have recommended bridge therapy for patients taking warfarin for atrial fibrillation.
When anticoagulation needs to be temporarily withheld, bridge therapy with a shorter-acting anticoagulant is used to reduce the time a patient is off anticoagulation. Bridge therapy is frequently used before and after surgical procedures. This is done to theoretically reduce the risk of thromboembolism from being off of anticoagulation. However bridging itself carries a risk of bleeding.
Current guidelines recommend that each patient should have an individualized risk:benefit assessment of bleeding and clotting risk when deciding whether to bridge. The CHA2DS2-VASc score and the HAS-BLED score are commonly used to assess clotting and bleeding risk, respectively. These recommendations are generally based on low-quality evidence or expert opinion.
The theory that the rate of thromboembolism in the perioperative period is increased after warfarin therapy is temporarily withheld has been brought into question by new evidence. Several studies (including a randomized trial) have demonstrated lower than expected rates of thromboembolism. The risk of thromboembolism also appears to not be amenable to bridge therapy.
Recent evidence
Pooled data from a prospective registry of patients with atrial fibrillation who underwent bridging therapy found higher rates of bleeding in patients who received bridging. Within 30 days of the procedure anticoagulation was withheld for, the rate of bleeding was 3.6% vs 1.2% in the bridge vs non-bridge groups. There were no differences in the rates of thromboembolic events.
The RE-LY study which compared warfarin with dabigatran included a pre-specified analysis of patients who had an elective procedure during the follow-up phase. In the group of patients who had warfarin temporarily withheld, the rates of major bleeding were 6.8% in the group who received bridge therapy and 1.6% in the group of patients who did not. Paradoxically, patients who were bridged had a 6-fold risk of thromboembolism compared to patients who were not bridged. This risk was statistically significant.
A meta-analysis of 34 trials involving over 12,000 patients found much higher rates of bleeding in patients who had bridge therapy compared to those who did not. Overall bleeding rates were 13.1% vs 3.4%, and major bleeding rates were 4.2% vs 0.9% in the bridge vs non-bridge groups.
The BRIDGE study was the first randomized trial examining perioperative bridging. Over 1800 patients receiving anticoagulation for atrial fibrillation were randomized to bridging or non-bridging. The rates of major bleeding were 3.2% in the group who received bridge therapy and 1.3% in the group of patients who did not. There were no differences in the rates of thromboembolic events.
Conclusion
The results of these recent trials call into question the routine use of bridging patients taking warfarin for atrial fibrillation in the perioperative period. The authors of a recent review suggest withholding bridging therapy for all patients taking warfarin for atrial fibrillation except in those with a high thromboembolism risk, and only if the risk of thromboembolism clearly outweighs the risk of bleeding.
Patients with mechanical valves have been largely excluded from studies examining risks and benefits of bridging, and they are still considered to be at high risk of thromboembolism for the purposes of risk assessment for bridge therapy.
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Hi Joe. Do you think the findings would be similar for patients on Eliquis?
Good question, because Eliquis is shorter acting than warfarin, bridging is not typically done. Usually Eliquis is held for a few days prior to the procedure and resumed the day after. Depending on the bleeding risk of the procedure it might be held for 2 days (low risk) or 3 days (high risk). There would need to be a rare confluence of circumstances for bridging to be needed with Eliquis (like someone with a very high bleeding risk that was not able to take medication orally).