Starting Lovenox with INR of 1.3 During a 4-Day Hold
Lovenox (enoxaparin) should be started now if the INR is already 1.3 and a 4-day hold is planned, as this INR level is approaching the sub-therapeutic range where thrombotic risk increases. 1
Rationale for Starting Lovenox Now
When managing anticoagulation interruption, the key considerations are:
- Current INR status: At 1.3, the INR is already below the therapeutic range (typically 2.0-3.0 for most indications)
- Thrombotic risk: Patients on warfarin typically have underlying conditions that increase thromboembolism risk
- Time remaining in the hold period: With potentially 3 more days of hold planned, the INR will likely decrease further
Bridging Protocol Considerations
The European Society of Cardiology guidelines recommend that bridging therapy with LMWH should be initiated when the INR falls below 2.0 1. With an INR of 1.3, the patient is already below this threshold and requires anticoagulation coverage.
Dosing Recommendations
The appropriate Lovenox dosing depends on the patient's thrombotic risk:
- High thrombotic risk (mechanical heart valves, recent VTE within 3 months, atrial fibrillation with prior stroke): Full therapeutic dose (1 mg/kg twice daily)
- Moderate thrombotic risk: Consider half-therapeutic dose (1 mg/kg once daily) 2, 3
- Low thrombotic risk: Prophylactic dose (40 mg once daily)
Implementation Timeline
- Today: Start Lovenox at the appropriate dose based on thrombotic risk
- Continue: Maintain Lovenox throughout the remaining hold period
- Resumption: When warfarin is restarted, continue Lovenox until the INR returns to the therapeutic range
Important Caveats
- Renal function: Adjust Lovenox dose if creatinine clearance is reduced
- Bleeding risk: Consider the procedure's bleeding risk when selecting the Lovenox dose
- Last dose timing: The last pre-procedural dose should be administered no less than 24 hours before the procedure 1
Special Considerations
For patients with mechanical heart valves, the evidence for using LMWH is primarily observational, and this is considered off-label use 1. However, it remains the standard of care when bridging is required.
If the patient has a history of heparin-induced thrombocytopenia, alternative anticoagulants should be considered.
Monitoring Recommendations
- Monitor for signs of bleeding or thrombosis during the bridging period
- Check platelet count if on Lovenox for more than 5 days
- Consider checking anti-Xa levels in patients with renal impairment or extreme body weights
By starting Lovenox now with an INR of 1.3 during a 4-day hold, you provide appropriate thromboprophylaxis during this vulnerable period when the anticoagulant effect of warfarin is diminishing.