What to do with a patient with mechanical mitral valve replacement (MVR) and epistaxis with an International Normalized Ratio (INR) of 1.3, where hemostasis has not been achieved, should warfarin be continued or switched to heparin (unfractionated heparin) or low molecular weight heparin (LMWH)?

Management of Epistaxis in a Patient with Mechanical Mitral Valve Replacement and Subtherapeutic INR

In a patient with mechanical mitral valve replacement (MVR) and uncontrolled epistaxis with a subtherapeutic INR of 1.3, warfarin should be temporarily discontinued and bridging therapy with intravenous unfractionated heparin (UFH) should be initiated once hemostasis is achieved.

Assessment of the Clinical Situation

Key Considerations:

• Patient has a mechanical mitral valve (high thrombotic risk)
• Current INR is 1.3 (significantly subtherapeutic)
• Active bleeding (epistaxis) without hemostasis
• Need to balance immediate bleeding risk vs thrombotic risk

Management Algorithm

Step 1: Control Active Bleeding

• Apply local measures to achieve hemostasis (nasal packing, cauterization)
• Temporarily hold warfarin until bleeding is controlled
• Avoid complete reversal with vitamin K as this creates high thrombotic risk 1, 2

Step 2: After Hemostasis is Achieved

• Initiate bridging therapy with intravenous UFH 1, 2
• Begin UFH with an initial bolus of 80 U/kg followed by infusion at 18 U/kg/hr 3
• Titrate to maintain aPTT at 1.5-2.5 times control (55-80 seconds) 2
• Monitor aPTT every 6 hours initially until stable 2

Step 3: Resumption of Oral Anticoagulation

• Restart warfarin once bleeding has been controlled for 24-48 hours
• Continue UFH until INR returns to therapeutic range 1
• Target INR should be 2.5-3.5 for mechanical mitral valve 1, 4

Rationale for This Approach

Mechanical mitral valves carry a high risk of thrombosis when anticoagulation is subtherapeutic. According to ACC/AHA guidelines, patients with mechanical mitral valve replacements are considered high-risk for thromboembolism 1. The guidelines specifically recommend that for patients at high risk of thrombosis (including those with any mechanical mitral valve replacement), therapeutic doses of intravenous UFH should be started when the INR falls below 2.0 1.

While LMWH has been used in some cases 5, the evidence supporting its use in mechanical valve patients is limited and primarily observational. There have been case reports of valve thrombosis with LMWH 6, making intravenous UFH the preferred option for this high-risk situation.

Important Considerations and Pitfalls

• Avoid high-dose vitamin K: This can create a hypercoagulable state and increase thrombotic risk 1, 2
• Fresh frozen plasma may be reasonable if urgent reversal is needed for life-threatening bleeding 1
• Continuous monitoring: Frequent monitoring of aPTT is essential to maintain therapeutic anticoagulation while minimizing bleeding risk 2
• Timing of resumption: Restart warfarin as soon as hemostasis is stable, with overlapping heparin until therapeutic INR is achieved 1
• Target INR: Recent evidence from the PROACT Mitral trial confirms that standard-dose warfarin (INR 2.5-3.5) remains appropriate for mechanical mitral valves 4

This approach balances the immediate need to control bleeding while protecting against the potentially catastrophic complication of valve thrombosis in a patient with a mechanical mitral valve replacement.