Should a patient with a history of valvular disease who has undergone mitral valve repair be on an anticoagulant, such as warfarin (vitamin K antagonist), postoperatively?

Anticoagulation After Mitral Valve Repair

Yes, patients who have undergone mitral valve repair should receive warfarin anticoagulation with a target INR of 2.5 (range 2.0-3.0) for the first 3 months postoperatively, followed by transition to low-dose aspirin (75-100 mg daily) for long-term therapy if they remain in normal sinus rhythm. 1, 2

Initial Postoperative Period (First 3 Months)

Warfarin is recommended for all patients during the first 3 months after mitral valve repair, regardless of cardiac rhythm, to prevent thromboembolism until the prosthetic annuloplasty ring is fully endothelialized. 1, 2

• Target INR should be 2.5 (range 2.0-3.0) during this period 1, 2, 3
• This recommendation applies even to patients in normal sinus rhythm with no other risk factors 1, 2
• The highest quality recent evidence from a 2016 Danish registry study of 2,188 patients demonstrated that warfarin use after mitral valve repair was associated with a 72% reduction in death/stroke at 3 months (HR=0.28, p=0.002) without excess bleeding risk 4

Initiation of Anticoagulation

Begin warfarin therapy early postoperatively using intravenous unfractionated heparin bridging until therapeutic INR is achieved. 1

• Start IV heparin with aPTT target of 1.5-2.0 until INR reaches therapeutic range 1
• Initiate warfarin at 2-5 mg daily (lower doses for elderly patients) 3
• Avoid loading doses as they increase hemorrhagic complications without providing faster protection 3

Long-Term Management (After 3 Months)

The decision to continue anticoagulation beyond 3 months depends on the presence of specific risk factors:

Continue Lifelong Warfarin (INR 2.0-3.0) if ANY of the following are present:

• Atrial fibrillation (most common indication) 1, 2
• Left ventricular ejection fraction <30% 1, 2
• Heart failure 1, 2
• History of prior thromboembolic event 2
• Left atrial thrombus found at surgery 1, 2
• Hypercoagulable condition 2

Transition to Aspirin 75-100 mg Daily if:

• Patient remains in normal sinus rhythm 1, 2
• No high-risk features listed above are present 1, 2
• Left atrial diameter <5.5 cm 1

Critical Pitfalls to Avoid

Do not use direct oral anticoagulants (DOACs) in the immediate post-repair period. 2

• DOACs have not been adequately studied for this indication 2
• Despite increasing DOAC use in clinical practice (from 12.4% to 37.3% between 2014-2018), they remain contraindicated per guidelines 5
• Warfarin remains the only FDA-approved anticoagulant for prosthetic valve-related indications 3

Monitor closely for new-onset atrial fibrillation after discharge. 6

• Approximately one-third of patients discharged in sinus rhythm will develop atrial fibrillation shortly after surgery 6
• If atrial fibrillation develops at any point, immediately switch from aspirin to lifelong warfarin anticoagulation 2

Do not routinely omit anticoagulation based on bleeding risk concerns. 4

• The 2016 Danish study showed only 1% major bleeding rate in warfarin-treated patients versus 2% in non-anticoagulated patients within 3 months 4
• The stroke/death reduction benefit (72%) far outweighs bleeding risk 4

Special Considerations for Rheumatic Heart Disease

Patients with rheumatic mitral valve disease who undergo repair require particularly careful attention to anticoagulation strategy. 2

• The ACC specifically addresses this population, recommending the same 3-month warfarin protocol followed by aspirin transition 2
• However, if high-risk features develop, continue warfarin indefinitely rather than transitioning to aspirin 2

Monitoring Requirements

Maintain close INR surveillance, particularly in the early postoperative period. 1, 3

• Check INR daily until stable, then at least weekly during the first month 1
• Elderly patients may require more frequent monitoring due to increased pharmacodynamic response 1, 3
• Target therapeutic range should be maintained >70% of the time for optimal efficacy 1