From the Guidelines
Bridging therapy in anticoagulation is a temporary strategy used when patients on long-term oral anticoagulants need to interrupt their regular medication for procedures or surgeries, and it is primarily recommended for patients at high thrombotic risk, such as those with mechanical heart valves, recent venous thromboembolism (within 3 months), or atrial fibrillation with high CHADS2 scores, as stated in the 2020 ACC/AHA guideline for the management of patients with valvular heart disease 1.
Overview of Bridging Therapy
Bridging therapy involves substituting the oral anticoagulant (typically warfarin) with a short-acting injectable anticoagulant, usually low molecular weight heparin (LMWH) like enoxaparin, during the perioperative period.
- The goal of bridging therapy is to minimize the time patients are without anticoagulation protection while reducing perioperative bleeding risk.
- LMWH has a shorter half-life and more predictable anticoagulant effect than warfarin, making it a suitable option for bridging therapy.
Recommendations for Bridging Therapy
According to the 2020 ACC/AHA guideline for the management of patients with valvular heart disease 1, bridging anticoagulation therapy during the preoperative time interval when the INR is subtherapeutic is reasonable on an individualized basis, with the risks of bleeding weighed against the benefits of thromboembolism prevention.
- For patients with mechanical heart valves who are undergoing minor procedures, continuation of VKA anticoagulation with a therapeutic INR is recommended.
- For patients with a bileaflet mechanical AVR and no other risk factors for thromboembolism who are undergoing invasive procedures, temporary interruption of VKA anticoagulation, without bridging agents while the INR is subtherapeutic, is recommended.
- For patients who are undergoing invasive procedures and have a mechanical AVR and any thromboembolic risk factor, an older-generation mechanical AVR, or a mechanical mitral valve replacement, bridging anticoagulation therapy is reasonable on an individualized basis.
Bridging Regimen
A typical bridging regimen involves stopping warfarin 5 days before the procedure to allow the INR to normalize.
- LMWH is then started (enoxaparin 1 mg/kg twice daily or 1.5 mg/kg once daily) when the INR falls below therapeutic range, usually 2-3 days before the procedure.
- The last dose of LMWH is given 24 hours before the procedure at half the regular dose.
- After the procedure, LMWH is restarted 24-72 hours later depending on bleeding risk, and warfarin is resumed when hemostasis is adequate.
- Both medications are continued until the INR returns to therapeutic range (usually 2.0-3.0), which typically takes 5-10 days.
Rationale Behind Bridging Therapy
The rationale behind bridging therapy is to minimize the time patients are without anticoagulation protection while reducing perioperative bleeding risk, as LMWH has a shorter half-life and more predictable anticoagulant effect than warfarin, as discussed in the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation 1.
From the FDA Drug Label
If rapid anticoagulation is indicated, heparin may be preferable for initial therapy. The answer to bridging therapy in anticoagulation is that heparin may be used as a bridging therapy when rapid anticoagulation is needed, as it can provide a quicker onset of action compared to warfarin.
- Key points:
- Heparin can be used for initial therapy when rapid anticoagulation is required.
- Warfarin may not be suitable for rapid anticoagulation due to its slower onset of action. 2
From the Research
Definition and Purpose of Bridging Therapy
- Bridging therapy with parenteral heparin, usually at therapeutic doses, aims to protect patients against thromboembolism during temporary periprocedural interruption of vitamin K antagonist (VKA) therapy 3.
- The decision to initiate bridging therapy is based on both the patient's and the procedure's thromboembolic and bleeding risks.
Patient Groups that May Benefit from Bridging Therapy
- Patient groups that may benefit from bridging therapy during temporary VKA interruption for a procedure include those who are at moderate-to-high risk of thromboembolism 3.
- Patients with mechanical heart valves may require bridging therapy with unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) to reduce the risk of thromboembolic events 4.
Risks and Complications of Bridging Therapy
- The most common complication of bridging is bleeding 5.
- Recent results from cohort studies and placebo-controlled randomized trials in the periprocedural use of heparin bridging for warfarin-treated patients reveal a consistent two- to three-fold increase in the risk of major bleeding and no benefit in terms of a reduction in the risk of stroke and systemic embolism 6.
Recommendations for Bridging Therapy
- The majority of patients on chronic warfarin, except those at high risk of thromboembolism, may safely interrupt and resume warfarin without heparin bridging in elective periprocedural settings 6.
- An individual peri-interventional management based on individual patients' risk profile and interventional factors is recommended for VKA and NOACs 5.
- A strategy that considers the pharmacokinetic properties of the direct oral anticoagulants, the bleeding risk of each procedure, and patient renal function would safely obviate the need for heparin bridging 6.