Bridging Heparin with Warfarin Protocol

General Principles

Bridging anticoagulation is defined as the administration of a short-acting anticoagulant during interruption of warfarin therapy when the INR is below therapeutic range, as recommended by the American College of Chest Physicians 1
Heparin should be continued until the INR returns to therapeutic levels to ensure continuous anticoagulation, according to the European Society of Cardiology 2
The decision to use bridging therapy should balance the risks of thromboembolism and bleeding, as stated by the American College of Cardiology 3

For therapeutic-dose LMWH, the American College of Chest Physicians recommends enoxaparin 1 mg/kg twice daily or 1.5 mg/kg once daily, and dalteparin 200 IU/kg once daily 4, 5
For therapeutic-dose UFH, the American College of Chest Physicians recommends IV infusion adjusted to maintain aPTT 1.5-2.5 times control or anti-factor Xa level of 0.3-0.7 IU/mL 4, 5
Once-daily LMWH dosing is preferred over twice-daily dosing for most patients, with a grade 2C recommendation 6

For patients on warfarin, the American College of Cardiology recommends checking INR at least weekly during initiation of therapy and at least monthly when anticoagulation is stable 3
Bridging therapy with UFH or LMWH is recommended for patients with mechanical heart valves undergoing procedures requiring warfarin interruption, as stated by the American College of Cardiology and the American Heart Association 3, 7
For patients with severe renal insufficiency, caution is advised with LMWH due to potential accumulation, according to the Mayo Clinic Proceedings 4

For patients requiring interruption of warfarin for procedures, the European Society of Cardiology recommends stopping warfarin 5 days before surgery, starting LMWH or UFH 1 day after acenocoumarol interruption, and resuming LMWH or UFH 1-2 days after surgery 2
The American Heart Association recommends continuing LMWH or UFH until the INR returns to therapeutic levels, and resuming warfarin on day 1 or 2 after surgery at the pre-operative maintenance dose plus a 50% boost dose for two consecutive days 2, 7