What is the recommended protocol for a heparin bridge to a Direct Oral Anticoagulant (DOAC)?

Heparin Bridge to Direct Oral Anticoagulants (DOACs)

Heparin bridging is not recommended when transitioning to DOACs due to increased bleeding risk without additional thrombotic protection. 1

Understanding DOAC Pharmacokinetics and Bridging Rationale

DOACs (apixaban, dabigatran, edoxaban, rivaroxaban) have rapid onset of action with peak anticoagulant effect within 2-4 hours after administration. This pharmacokinetic profile eliminates the need for bridging therapy that is traditionally used with vitamin K antagonists (VKAs).

The American College of Chest Physicians (ACCP) guidelines specifically state:

• For patients transitioning from parenteral anticoagulants to DOACs, the DOAC should be started 0-2 hours before the next scheduled dose of parenteral anticoagulant 1
• When transitioning from intravenous unfractionated heparin (UFH), the DOAC should be started immediately after stopping the UFH infusion 1
• No bridging is necessary when initiating DOACs due to their rapid onset of action 1, 2

Protocol for Transitioning from Heparin to DOAC

1. For patients on continuous IV unfractionated heparin:

   • Stop IV heparin infusion
   • Administer first DOAC dose immediately after stopping infusion
   • No overlap period required

2. For patients on subcutaneous LMWH (e.g., enoxaparin):

   • For once-daily LMWH: Administer DOAC at the time the next LMWH dose would have been due
   • For twice-daily LMWH: Administer DOAC 0-2 hours before the next scheduled LMWH dose would have been due
   • Do not give the next scheduled dose of LMWH

3. For patients with renal impairment:

   • No special bridging protocol is needed, but DOAC dosing may need adjustment based on creatinine clearance 1
   • For severe renal impairment (CrCl <30 mL/min), consider longer interruption times for DOACs before procedures 1

Special Considerations

Perioperative Management

When managing DOACs around procedures, the guidelines recommend:

• Time-based interruption of DOACs based on bleeding risk and renal function 1
• No heparin bridging during DOAC interruption for procedures 1
• Resumption of DOACs at least 6 hours after procedures with low bleeding risk 1
• For high bleeding risk procedures, delay DOAC resumption for 48-72 hours 1

Thrombotic Risk Assessment

While bridging is not recommended for DOACs, patients with very high thrombotic risk may require individualized approaches:

• Mechanical mitral valves
• Recent stroke/TIA (<3 months)
• Recent VTE (<1 month)
• CHA₂DS₂-VASc score ≥7 1

Common Pitfalls to Avoid

1. Unnecessary bridging: The most common error is implementing heparin bridging when initiating DOACs, which increases bleeding risk without additional thrombotic protection 1, 3

2. Overlapping full anticoagulant doses: Administering therapeutic doses of both heparin and DOAC simultaneously significantly increases bleeding risk 1

3. Misunderstanding pharmacokinetics: Unlike warfarin, DOACs have rapid onset and offset, making bridging unnecessary 2

4. Inappropriate post-procedure management: Resuming DOACs too early after high bleeding risk procedures increases bleeding complications 1

By following these evidence-based recommendations, clinicians can safely transition patients from heparin products to DOACs without the need for bridging therapy, thereby minimizing bleeding risk while maintaining effective anticoagulation.