What is the role of Lovenox (enoxaparin) for atrial fibrillation (Afib) to bridge from warfarin (Coumadin) before surgery?

From the Guidelines

Bridging with Lovenox (enoxaparin) is not recommended for most patients with atrial fibrillation who are on warfarin and require surgery, as it has been shown to increase the risk of bleeding without providing a significant reduction in thromboembolic events. The 2022 American College of Chest Physicians clinical practice guideline 1 supports this recommendation, citing the BRIDGE trial and other studies that demonstrate the increased risk of major bleeding associated with bridging anticoagulation. The guideline suggests that bridging may be appropriate only in patients with a very high thromboembolic risk.

Key Considerations

• The BRIDGE trial showed that no bridging was noninferior to low-molecular-weight heparin (LMWH) for the outcome of arterial thromboembolism (ATE), but bridging conferred a threefold increased risk for major bleeding 1.
• The 2019 AHA/ACC/HRS focused update on atrial fibrillation also recommends against routine bridging anticoagulation, citing the lack of benefit and increased risk of bleeding 1.
• Patients with atrial fibrillation who require warfarin interruption for surgery should be assessed individually for their thromboembolic and bleeding risks to determine the best perioperative anticoagulation strategy.

Perioperative Management

• For patients who do require bridging, the typical protocol involves stopping warfarin 5 days before surgery and starting Lovenox when the INR falls below 2.0, usually 2-3 days before surgery.
• The recommended dose of Lovenox is 1 mg/kg subcutaneously twice daily, with dose adjustments for patients with renal impairment.
• Lovenox should be stopped 24 hours before surgery for most procedures, or 48 hours before for high bleeding risk procedures, and restarted 24-72 hours after surgery depending on bleeding risk.

From the Research

Lovenox for Afib to Bridge from Warfarin Before Surgery

• The use of Lovenox (enoxaparin) as a bridging anticoagulant for patients with atrial fibrillation (Afib) on warfarin before surgery has been studied in several research papers 2, 3, 4, 5.
• A study published in Circulation in 2007 found that continuation of warfarin throughout pulmonary vein ablation without administration of enoxaparin is safe and efficacious 2.
• The Seventh American College of Chest Physicians (ACCP) Conference on Antithrombotic and Thrombolytic Therapy provides guidelines for outpatient management of anticoagulation therapy, including the use of low-molecular-weight heparin (LMWH) as a bridging agent 3.
• A retrospective cohort study published in The American Journal of Cardiology in 2009 found that the use of enoxaparin as a bridging agent in patients with mechanical heart valves (MHV) and nonvalvular Afib had similar thromboembolic and hemorrhagic risk 4.
• A decision analysis published in Archives of Internal Medicine in 1995 compared the risks and benefits of antiarrhythmic prophylaxis vs warfarin anticoagulation to prevent thromboembolic events among patients with Afib, and found that warfarin therapy appears to be the safest strategy for thromboembolism prevention 6.
• A retrospective evaluation published in The American Journal of Cardiology in 2018 found that patients with Afib on warfarin receive excessive low-molecular-weight heparin bridging in the setting of endoscopy, and that cardiologists were less likely to prescribe bridging than noncardiology providers 5.

Bridging Therapy

• The decision to use bridging therapy is determined by balancing the risk of bleeding against the risk of thromboembolism 3.
• The ACCP recommends starting warfarin with unfractionated heparin or LMWH for at least five days and continuing until a therapeutic INR is achieved 3.
• The use of LMWH as a bridging agent has been found to be safe and effective in several studies 2, 4.

Patient-Specific Factors

• The CHADS2 score, CHA2DS2-VASc score, and a history of stroke are strong predictors of bridging therapy 5.
• Cardiologists are less likely to prescribe bridging therapy than noncardiology providers, suggesting a need for increased involvement in decision making 5.