Aspirin After Mitral Valve Repair
For patients after mitral valve repair with a prosthetic annuloplasty band and normal sinus rhythm, aspirin 75-100 mg daily for the first 3 months is recommended over warfarin, followed by continuation of aspirin monotherapy long-term. 1
Initial 3-Month Period
Antiplatelet therapy with aspirin is preferred over vitamin K antagonist (VKA) therapy during the first 3 months after mitral valve repair. 1 The American College of Chest Physicians specifically recommends aspirin 50-100 mg daily over warfarin for patients with mitral valve repair using a prosthetic band who remain in normal sinus rhythm. 1
- The rationale is that mitral valve repair (unlike replacement) preserves native valve tissue and has lower thrombotic risk compared to prosthetic valves. 1
- A study of 162 patients demonstrated significantly fewer thromboembolic events with antiplatelet therapy compared to warfarin (RR 0.16,95% CI 0.03-0.86), with no difference in hemorrhage rates. 1
- The bleeding risk with warfarin may outweigh benefits in this lower-risk population, particularly given the preserved native valve architecture. 1
After 3 Months
Continue aspirin 75-100 mg daily indefinitely after the initial 3-month period. 1 The 2021 ACC/AHA guidelines indicate that aspirin is reasonable for all patients with bioprosthetic or repaired valves long-term. 1
- The annual thromboembolic risk after mitral valve repair is substantially lower than after valve replacement, supporting the use of aspirin alone rather than warfarin. 1
- Long-term aspirin provides adequate stroke prevention while minimizing bleeding complications. 1
Critical Exceptions Requiring Warfarin Instead
Switch to warfarin (INR 2.0-3.0) if any of the following risk factors develop: 1
- Atrial fibrillation (most common indication for escalation to warfarin) 1
- Previous thromboembolic event 1
- Left ventricular systolic dysfunction 1
- Hypercoagulable condition 1
- Left atrial thrombus 1
These patients require full anticoagulation regardless of valve type, as their stroke risk is driven by these comorbidities rather than the repaired valve itself. 1
Important Caveats
Do not confuse mitral valve repair with mitral valve replacement. 2 Bioprosthetic mitral valve replacement requires warfarin (INR 2.5) for the first 3-6 months, not just aspirin, due to higher thrombotic risk until the prosthesis endothelializes. 1, 2 Mechanical mitral valve replacement requires lifelong warfarin with INR target of 3.0 plus aspirin. 2
Verify the patient is in normal sinus rhythm. 1 The aspirin-only strategy applies specifically to patients without atrial fibrillation. If atrial fibrillation is present or develops, warfarin becomes mandatory. 1
Recent evidence from 2018 comparing VKA versus aspirin after mitral valve repair showed similar combined rates of thromboembolism and bleeding (9.2% vs 11%) at 3 months, with low thromboembolic rates in both groups. 3 This supports the guideline recommendation favoring aspirin given its simpler management and lower bleeding risk when event rates are equivalent. 3