How to bridge with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) in patients requiring temporary cessation of oral anticoagulation?

From the Guidelines

Bridging with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) should be considered for patients at high thrombotic risk when oral anticoagulation needs to be temporarily discontinued, as recommended by the 2020 ACC/AHA guideline for the management of patients with valvular heart disease 1. When interrupting oral VKA therapy, the agent is usually stopped 3 to 4 days before the procedure and is restarted postoperatively as soon as bleeding risk allows.

• Bridging anticoagulation with intravenous UFH or subcutaneous LMWH is started when the INR falls below the therapeutic threshold, usually 36 to 48 hours before surgery, and is stopped 4 to 6 hours (for intravenous UFH) or 12 hours (for subcutaneous LMWH) before the procedure.
• The decision to bridge should be individualized, taking into account the trade-offs between thrombosis and bleeding, as there are no randomized comparative-effectiveness trials evaluating a strategy of bridging versus no bridging in adequate numbers of patients with prosthetic heart valves who need temporary interruption of oral anticoagulant therapy 1.
• For patients at high risk of thromboembolism, therapeutic-dose LMWH (enoxaparin 1 mg/kg twice daily or 1.5 mg/kg once daily) is recommended, while for moderate-risk patients, prophylactic-dose LMWH (enoxaparin 40 mg daily) may be sufficient, as suggested by the american heart association/american college of cardiology foundation guide to warfarin therapy 1.
• UFH is generally reserved for patients with severe renal impairment or those requiring very tight control, administered as a continuous infusion with a target aPTT of 1.5-2.5 times normal.
• The last dose of LMWH should be given 24 hours before the procedure, with half the usual dose if using twice-daily regimens, and bridging should resume 24-72 hours post-procedure based on bleeding risk, with oral anticoagulation restarted when hemostasis is adequate.

From the Research

Bridging with Heparin

• Bridging therapy with heparin is used in patients who require temporary cessation of oral anticoagulation for an elective surgical or invasive procedure 2, 3, 4, 5, 6.
• The decision to use bridging therapy depends on the patient's risk of thromboembolism and bleeding 4, 5.
• Low molecular weight heparin (LMWH) and unfractionated heparin (UFH) are the two types of heparin used for bridging therapy 2, 3, 4, 5, 6.

Low Molecular Weight Heparin (LMWH)

• LMWH has more predictable pharmacokinetic and pharmacodynamic properties compared to UFH 2.
• LMWH can be administered subcutaneously, once daily without laboratory monitoring 2.
• LMWH is as effective as and safer than UFH for most clinical indications 2.
• The use of LMWH as bridging therapy is associated with low rates of thromboembolism and bleeding 3, 4, 6.

Unfractionated Heparin (UFH)

• UFH has unpredictable pharmacokinetic and pharmacodynamic properties due to its binding to endothelial cells, platelet factor 4, and platelets 2.
• UFH requires laboratory monitoring to adjust the dose 2.
• UFH is associated with a higher risk of bleeding compared to LMWH 3, 6.

Clinical Outcomes

• Studies have shown that LMWH and UFH have similar rates of overall adverse events, major composite adverse events, and major bleeds 3, 6.
• The thromboembolic event rates are lower with LMWH compared to UFH 3.
• Postoperative heparin use is associated with an increased risk of major bleeding, especially in patients with multiple comorbidities and those undergoing vascular, general, and major surgery 3.

Recommendations

• The decision to use bridging therapy should be based on the patient's individual risk of thromboembolism and bleeding 4, 5.
• LMWH is recommended as the first-line bridging therapy due to its ease of administration and predictable anticoagulant effects 4.
• UFH may be used in patients with severe renal insufficiency or those who require close monitoring of their anticoagulation therapy 2, 5.
• Further studies are needed to optimize bridging therapy for specific patients and procedures 4, 5, 6.