Is bridging with heparin (unfractionated heparin) necessary in patients on anticoagulant therapy?

Heparin Bridging: A Risk-Stratified Approach

Heparin bridging should be reserved only for patients at high thromboembolic risk undergoing procedures requiring anticoagulation interruption, while the majority of patients—including those at low-to-moderate risk—should NOT receive bridging therapy due to increased bleeding risk without proven benefit. 1

When NOT to Bridge (Most Patients)

Low-to-Moderate Thromboembolic Risk Patients

• Patients with non-valvular atrial fibrillation should NOT receive heparin bridging, as demonstrated by large randomized trials showing no reduction in thrombotic events but a 2-3 fold increase in major bleeding when bridging is used 1, 2
• Patients with venous thromboembolism (VTE) beyond 3 months should NOT be bridged, as systematic reviews show bridging increases bleeding (3.9% vs 0.4%) without reducing recurrent VTE 1
• Patients with thrombophilia (Factor V Leiden, prothrombin mutations, protein C/S deficiency) do NOT require bridging despite laboratory abnormalities 1

Minor Procedures

• Continue warfarin without interruption for dental procedures, dermatologic procedures (skin cancer excisions), ophthalmologic procedures (cataract surgery), and diagnostic colonoscopy 1
• These procedures can be safely performed with INR in therapeutic range (2.0-3.0) 1

When TO Bridge (High-Risk Patients Only)

High Thromboembolic Risk Indications

Bridge with therapeutic-dose LMWH or unfractionated heparin in:

• Mechanical mitral valve or any mechanical valve with prior stroke/TIA 1
• Atrial fibrillation WITH mitral stenosis 1
• Recent VTE within 3 months 1
• Severe thrombophilia with active thrombotic complications 1
• Selected active cancer patients with high VTE risk 1

Practical Bridging Protocol (When Indicated)

Pre-Procedure Management

• Stop warfarin 5 days before procedure to allow INR to decrease to ≤1.5 1
• Start LMWH 3-4 days before procedure using therapeutic dosing: enoxaparin 1 mg/kg twice daily or dalteparin 100 IU/kg twice daily 1, 3
• Last LMWH dose should be 24 hours before procedure 1, 3
• For renal insufficiency (CrCl <30 mL/min), use IV unfractionated heparin instead of LMWH 1

Post-Procedure Management

Critical timing based on bleeding risk:

• High-bleed-risk procedures (cardiac, intracranial, spinal surgery, major vascular surgery): Delay therapeutic-dose heparin for 48-72 hours post-operatively 1
• Consider stepwise approach: prophylactic-dose LMWH (enoxaparin 40 mg daily) for first 24-48 hours, then increase to therapeutic dose 1
• Low-to-moderate-bleed-risk procedures: Resume therapeutic-dose LMWH 24 hours post-procedure if adequate hemostasis achieved 1
• Resume warfarin the evening of or morning after surgery at usual maintenance dose (or 1.5x maintenance dose for 2 days) 1, 3

Direct Oral Anticoagulants (DOACs)

Heparin bridging is NOT indicated for DOACs due to their short half-lives and rapid onset of action 1, 2

• Simply interrupt DOACs based on renal function and procedure bleeding risk (2-5 half-lives pre-procedure) 1
• Resume DOACs 24-72 hours post-procedure depending on bleeding risk and hemostasis 1
• Exception: Patients unable to take oral medications postoperatively may require temporary heparin 1

Critical Pitfalls to Avoid

• Do not bridge based solely on anticoagulation indication—the majority of AF patients, even with CHADS₂ scores of 5-6, do NOT benefit from bridging 1
• Do not resume therapeutic-dose heparin too early postoperatively—this is the primary driver of major bleeding complications 1
• Do not bridge patients on DOACs—this causes harm without benefit 2
• Assess surgical hemostasis before any postoperative heparin—examine wound drainage (amount, type, progression) before initiating therapeutic doses 1
• Major bleeding requires prolonged anticoagulation interruption, which paradoxically increases thrombotic risk—prevention of bleeding is paramount 1