When is mitral valve replacement recommended?

Mitral Valve Replacement Indications

Mitral valve replacement is definitively indicated for symptomatic patients with chronic severe primary mitral regurgitation (MR) who have left ventricular ejection fraction (LVEF) >30%, though mitral valve repair should be attempted first whenever feasible. 1

Primary Mitral Regurgitation

Class I Indications (Strongest Recommendations)

Symptomatic severe primary MR:

• Mitral valve surgery is mandatory for symptomatic patients (Stage D) with LVEF >30% 1
• Symptoms include decreased exercise tolerance, exertional dyspnea, or heart failure 1
• Severe MR defined by: vena contracta ≥0.7 cm, regurgitant volume ≥60 mL, regurgitant fraction ≥50%, ERO ≥0.40 cm² 1

Asymptomatic severe primary MR with LV dysfunction:

• Surgery is required when LVEF is 30-60% and/or LVESD ≥40 mm (Stage C2) 1
• This prevents irreversible ventricular damage and improves long-term survival 1

Concomitant cardiac surgery:

• Mitral valve repair or replacement is indicated when patients with chronic severe primary MR undergo cardiac surgery for other indications 1

Repair vs. Replacement Decision

Mitral valve repair is strongly preferred over replacement when:

• Primary MR is limited to the posterior leaflet (repair recommended in preference to replacement) 1
• Anterior leaflet or both leaflets are involved AND a successful, durable repair can be accomplished 1
• Repair preserves better long-term outcomes, ventricular function, and avoids anticoagulation complications 1

Mitral valve replacement becomes necessary when:

• Valve anatomy is unfavorable for repair (extensive calcification, severe leaflet destruction) 1
• Rheumatic disease with severe leaflet restriction and loss of central coaptation 1
• Prior infective endocarditis with extensive valve destruction 1
• Radiation heart disease with significant leaflet thickening 1

Class IIa Indications (Reasonable to Perform)

Asymptomatic severe primary MR with preserved LV function (Stage C1):

• Repair is reasonable when LVEF >60% and LVESD <40 mm at a Heart Valve Center of Excellence with >95% repair success rate and <1% mortality 1
• Also reasonable with new-onset atrial fibrillation or resting pulmonary hypertension (PA systolic pressure >50 mmHg) 1

Class IIb Indications (May Be Considered)

Severely reduced LV function:

• Surgery may be considered in symptomatic patients with chronic severe primary MR and LVEF ≤30% (Stage D), though outcomes are less favorable 1

Secondary (Ischemic) Mitral Regurgitation

Key Differences in Management

Lower thresholds define severe secondary MR:

• ERO ≥0.20 cm² (versus ≥0.40 cm² for primary MR) 1, 2
• Regurgitant volume ≥30 mL (versus ≥60 mL for primary MR) 1, 2
• Regurgitant fraction ≥50% 1

Class I Indications

Concomitant CABG:

• Surgery is indicated for patients with severe secondary MR undergoing CABG when LVEF >30% 1, 2
• This represents the strongest indication for intervention in secondary MR 1, 2

Class IIb Indications

Isolated mitral valve surgery:

• May be considered in patients with severe secondary MR and LVEF >30% who remain symptomatic despite optimal medical management (including cardiac resynchronization therapy if indicated) and have low surgical risk 1, 2
• Critical caveat: No conclusive evidence exists for survival benefit after isolated mitral valve intervention in secondary MR 1

Repair vs. Replacement in Secondary MR

Repair is preferred but with important caveats:

• Mitral valve repair is the preferred method for secondary MR 1, 2
• Typically performed with small undersized rigid annuloplasty ring 2
• Replacement should be considered with unfavorable morphological characteristics or high risk of MR recurrence 1, 2
• Chordal-sparing techniques must be used during replacement to preserve ventricular function 2

Mitral Stenosis

Mitral valve replacement is indicated when:

• Severe mitral stenosis (valve area <1.5 cm²) with marked dyspnea, pulmonary edema, hemoptysis, atrial fibrillation, recurrent systemic emboli, or right ventricular failure 3
• Significant valve calcification or major concomitant mitral regurgitation precludes commissurotomy or balloon valvotomy 3
• Failed prior commissurotomy or balloon valvotomy 4

Mechanical valves are preferred over bioprosthetic valves for mitral stenosis:

• Lower reoperation rates with mechanical valves 4
• Requires lifelong anticoagulation but provides better durability 4, 3

Critical Assessment Before Surgery

Mandatory reassessment after optimization:

• Severity of secondary MR must be reassessed after optimized medical treatment before surgical decisions 1, 2
• Optimal heart failure therapy includes ACE inhibitors/ARBs, beta-blockers, and mineralocorticoid receptor antagonists 1, 2
• Cardiac resynchronization therapy should be performed if indicated before considering isolated mitral surgery 1, 2

Dynamic assessment:

• Secondary MR is dynamic; echocardiographic quantification during exercise may favor combined surgery 1, 2
• Tricuspid regurgitation severity and right ventricular function must be evaluated 1

Common Pitfalls to Avoid

Do not delay surgery in symptomatic severe primary MR with preserved LVEF:

• Waiting for symptoms to worsen or LVEF to decline results in irreversible ventricular damage and worse outcomes 1

Do not perform isolated mitral surgery for secondary MR without exhausting medical optimization:

• Unlike primary MR, secondary MR lacks proven survival benefit from isolated valve intervention 1
• Medical therapy and CRT must be optimized first 1, 2

Do not assume repair is always possible:

• While repair is preferred, attempting repair in unfavorable anatomy leads to high recurrence rates and need for reoperation 1, 2
• Replacement is appropriate when durable repair is unlikely 1, 2

Do not use primary MR severity thresholds for secondary MR:

• Secondary MR has lower thresholds (ERO ≥0.20 cm² vs ≥0.40 cm²) 1, 2