What are the guidelines for bridging with Coumadin (warfarin)?

From the Guidelines

Coumadin bridging should be individualized based on the patient's thrombotic and bleeding risks, with a general approach of stopping warfarin 5 days before surgery and starting low molecular weight heparin (LMWH) when the INR falls below 2.0, typically 3 days before surgery, as recommended by the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1.

Key Considerations

• The decision to bridge should balance the risks of stroke and bleeding, taking into account the patient's specific condition, such as the presence of mechanical heart valves or atrial fibrillation with a high CHA2DS2-VASc score.
• For patients with high thrombotic risk, bridging with LMWH is recommended, whereas for low-risk patients, bridging may be unnecessary and potentially harmful due to increased bleeding risk.
• The timing and dosing of LMWH should be adjusted based on the patient's renal function, body weight, and bleeding risk, with options including therapeutic, intermediate, or prophylactic doses.

Bridging Protocol

• Stop warfarin 5 days before surgery to allow the INR to normalize (below 1.5).
• Begin LMWH (such as enoxaparin 1 mg/kg twice daily or 1.5 mg/kg once daily) when the INR falls below 2.0, typically 3 days before surgery.
• Stop LMWH 24 hours before surgery for therapeutic doses or 12 hours before for prophylactic doses.
• After surgery, resume LMWH 24-72 hours postoperatively depending on bleeding risk, and restart warfarin within 24 hours when hemostasis is adequate.
• Continue LMWH until the INR returns to the therapeutic range (typically 2.0-3.0) for two consecutive days, as recommended by the 2012 Blood journal article on how to treat anticoagulated patients undergoing an elective procedure or surgery 1.

Important Considerations

• The patient's preprocedural and postprocedural warfarin management should follow a similar strategy, with a day 1 INR drawn to ensure it is 1.5.
• Bridging therapy using LMWH injections should start 36 hours after the last warfarin dose, usually around 3 days before surgery.
• The last dose of LMWH is administered 24 hours before the procedure using half the normal daily dose because discontinuing LMWH therapy too close to the time of surgery may increase the risk of bleeding due to a residual anticoagulant effect.

From the FDA Drug Label

The dosage and administration of warfarin sodium tablets must be individualized for each patient according to the particular patient’s PT/INR response to the drug. For patients with a first episode of DVT or PE secondary to a transient (reversible) risk factor, treatment with warfarin for 3 months is recommended For patients with a first episode of idiopathic DVT or PE, warfarin is recommended for at least 6 to 12 months.

The guidelines for Coumadin bridge are not explicitly stated in the provided drug label. However, the label provides recommendations for the treatment of Venous Thromboembolism (VTE), including Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE), with warfarin.

• The recommended treatment duration for VTE is based on the patient's risk factors and the presence of transient or reversible risk factors.
• The label recommends adjusting the dose of warfarin to maintain a target INR of 2.5 (range, 2.0 to 3.0) for all treatment durations.
• The decision to bridge with Coumadin should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history 2.

From the Research

Guidelines for Coumadin Bridge

• The American College of Chest Physicians (ACCP) guidelines suggest bridging therapy with therapeutic doses of low-molecular-weight heparin (LMWH) in patients with atrial fibrillation (AF) if at high or moderate thromboembolic (TE) risk, and with reduced doses in patients with low TE risk 3.
• A study found that bridging oral anticoagulation with enoxaparin in AF patients supports a predefined bridging regimen based on the individual patient's TE risk and renal function, with patients with low TE risk or with impaired renal function being bridged effectively and safely with reduced LMWH doses 3.
• Another study revealed an overall thromboembolic complication rate of 1.22 (95% CI 0.81-1.77) and an overall major bleed rate of 2.94 (95% CI 2.28-3.74) in patients receiving long-term oral anticoagulation who underwent bridging therapy with mostly treatment-dose low-molecular-weight heparin for both major and non-major elective invasive procedures or surgeries 4.
• Perioperative bridging therapy with heparin, either unfractionated heparin or low-molecular-weight heparin, appears to be safe and effective for patients, including those with mechanical heart valves, receiving long-term oral anticoagulation who require temporary interruption, especially for non-high-bleeding risk procedures such as minor surgery and invasive procedures 4, 5.

Bridging Therapy with Low-Molecular-Weight Heparin

• Low-molecular-weight heparin (LMWH) may be an effective alternative to unfractionated heparin (UFH) for bridging therapy, with potential cost-savings due to the ability to provide bridging therapy in the outpatient setting 5.
• A study found that LMWH bridging regimens using postoperative bleeding risk assessments optimized good clinical outcomes, and bridging therapy with LMWH appears to be at least as safe as UFH and produces substantial cost savings through reduction in length of stay in the hospital 4.

Assessment of Anticoagulation

• A study assessed the relationships between rivaroxaban-specific anti-factor Xa activity (AXA) and unfractionated heparin (UFH)-specific AXA, and determined the cutoff level for UFH-specific AXA in critical situations for patients undergoing rivaroxaban therapy, finding a positive dose-dependent correlation between rivaroxaban-specific and UFH-specific AXA 6.
• The study suggests that if a rivaroxaban-specific anti-Xa assay is unavailable, the chromogenic anti-Xa assay for UFH may be useful to assess the anticoagulant effects of rivaroxaban 6.