How to manage a patient with mitral valve replacement on warfarin (anticoagulant) presenting with elevated International Normalized Ratio (INR) and a decrease in Hemoglobin (Hb)?

Management of Supratherapeutic INR with Bleeding in Mechanical Mitral Valve Patient

Immediately hold warfarin, administer intravenous vitamin K (1-2 mg by slow IV infusion), and give fresh frozen plasma or prothrombin complex concentrate to rapidly reverse anticoagulation while simultaneously investigating and treating the source of bleeding. 1

Immediate Assessment and Stabilization

Determine Bleeding Severity and INR Level

• Check current INR immediately and assess for active bleeding (hematemesis, melena, hematuria, intracranial hemorrhage, or other major bleeding sites) 1, 2
• Obtain complete blood count to quantify the hemoglobin drop and assess ongoing blood loss 1
• Identify bleeding source through focused examination: gastrointestinal (most common), genitourinary, intracranial, or retroperitoneal 3, 2

Risk Stratification

This patient is high-risk because: 1

• Mechanical mitral valve (higher thrombotic risk than aortic position)
• Active bleeding with hemoglobin drop
• Supratherapeutic INR increases hemorrhage risk exponentially

Anticoagulation Reversal Strategy

For Active Bleeding with Elevated INR (Any Level)

Aggressive reversal is mandatory: 1, 2

• Hold warfarin immediately 1, 3
• Administer intravenous vitamin K 1-2 mg by slow IV infusion (NOT high-dose 5-10 mg, as this creates prolonged hypercoagulability and difficulty re-establishing therapeutic anticoagulation) 1
• Give fresh frozen plasma OR prothrombin complex concentrate for immediate clotting factor replacement—prothrombin complex concentrate is preferred when available as it works faster and requires less volume 1, 2
• Avoid high-dose vitamin K (>2.5 mg) as this creates a hypercoagulable state and makes subsequent warfarin dosing extremely difficult 1

Rationale for Low-Dose Vitamin K

The 2014 ACC/AHA guidelines specifically warn that fresh frozen plasma and prothrombin complex concentrate have shorter half-lives than warfarin's anticoagulant effect, so adding 1-2 mg vitamin K prevents rebound elevation of INR after clotting factors are metabolized 1

Thrombosis Prevention During Reversal

Bridging Anticoagulation Timing

This is the critical management dilemma: balancing bleeding control against valve thrombosis risk 1

• Mechanical mitral valves are HIGH-RISK for thrombosis—the target INR is 2.5-3.5 (higher than aortic valves) precisely because mitral position carries greater thrombotic risk 1, 4
• Once bleeding is controlled and hemoglobin stabilizes, initiate bridging with intravenous unfractionated heparin (NOT subcutaneous LMWH initially, as UFH can be stopped immediately if bleeding recurs) 1
• Start heparin when INR falls below 2.0 and bleeding has demonstrably stopped for at least 12-24 hours 1
• Continue heparin until INR is therapeutic (2.5-3.5) on warfarin for at least 48 hours with two consecutive measurements >24 hours apart 1, 4

Warfarin Reinitiation

Dosing Strategy

• Restart warfarin at a lower dose than previous maintenance (typically reduce by 10-20% of weekly dose) once bleeding fully controlled 1, 5
• Avoid loading doses—resume with 2-5 mg daily depending on patient age and previous dose requirements 4, 5
• Monitor INR daily initially, then every 2-3 days until stable in therapeutic range of 2.5-3.5 1, 4

Target INR for Mechanical Mitral Valve

The target INR is 2.5-3.5 for ALL mechanical mitral valves (higher than the 2.0-3.0 used for mechanical aortic valves) 1, 4

Investigation of Bleeding Cause

Identify Precipitating Factors

Common causes of supratherapeutic INR with bleeding: 1, 6

• Medication interactions: antibiotics (especially ceftriaxone, fluoroquinolones, metronidazole), NSAIDs, amiodarone, azole antifungals 1, 6
• Dietary changes: decreased vitamin K intake, alcohol consumption 1
• Illness: fever, diarrhea, heart failure exacerbation, liver dysfunction, thyroid disease 1
• Gastrointestinal lesions: peptic ulcer, arteriovenous malformations, malignancy 3, 2

Diagnostic Workup

• Review all medications including over-the-counter drugs and supplements 1
• Endoscopy if GI bleeding suspected (most common source) 3
• CT imaging if intracranial or retroperitoneal bleeding suspected 2
• Assess liver and thyroid function 1

Common Pitfalls to Avoid

Critical Errors in Management

• Never give high-dose vitamin K (>2.5 mg) routinely—this creates warfarin resistance lasting weeks and puts the patient at thrombotic risk 1
• Never restart warfarin at full dose after major bleeding—this frequently leads to recurrent supratherapeutic INR 5
• Never delay heparin bridging excessively—mechanical mitral valves can thrombose within days of subtherapeutic anticoagulation 1
• Never use LMWH as initial bridging in active bleeding—its longer half-life and irreversibility make it dangerous if bleeding recurs 1

Monitoring Intensity

• INR must be checked daily during the acute phase and reversal period 1
• Serial hemoglobin measurements every 6-12 hours until stable 3, 2
• Activated partial thromboplastin time (aPTT) monitoring when on heparin bridge 1

Hospital Admission Requirement

This patient requires hospitalization for: 3, 2

• Active bleeding with hemoglobin drop
• Need for IV vitamin K and clotting factor replacement
• High thrombotic risk requiring careful bridging
• Frequent laboratory monitoring
• Investigation of bleeding source