Treatment of Mitral Regurgitation
The treatment of mitral regurgitation requires a tailored approach based on whether it is primary (degenerative) or secondary (functional), with optimized guideline-directed medical therapy as the foundation for all patients, and surgical or transcatheter interventions reserved for specific indications. 1
Classification and Initial Assessment
Mitral regurgitation (MR) is classified into two main types:
- Primary MR: Direct valve abnormality (degenerative, myxomatous disease, flail leaflet)
- Secondary MR: Dysfunction of surrounding structures (LV dilation, papillary muscle displacement) 1
Assessment requires:
- Echocardiography to determine MR severity, LV size/function, LA size, and valve anatomy
- Cardiac MRI when echo measurements are ambiguous
- Exercise testing to unmask symptoms in apparently asymptomatic patients 1
Treatment Algorithm
1. Guideline-Directed Medical Therapy (GDMT)
For all patients with MR, especially secondary MR:
- ACE inhibitors/ARBs
- Beta-blockers
- Mineralocorticoid receptor antagonists
- SGLT2 inhibitors
- Sacubitril/valsartan (for HFrEF) 1
2. Cardiac Resynchronization Therapy (CRT)
- Consider CRT if indicated (typically for patients with QRS prolongation, LBBB, and reduced EF) 1
3. Interventional Approaches
For Primary MR:
- Surgical repair is strongly preferred over replacement when feasible 1
- Surgery indicated when:
- LVEF ≤60% or LVESD ≥40 mm
- New-onset atrial fibrillation
- Pulmonary hypertension (PASP ≥50 mmHg)
- High likelihood of successful repair (>95%) with low mortality risk (<1%) 1
For Secondary MR:
- Optimize GDMT and CRT first (if indicated)
- Consider surgical intervention for:
- Patients with LVEF >30% and severe MR without indication for coronary revascularization
- Patients with persistent symptoms despite optimal medical therapy 1
Transcatheter Edge-to-Edge Repair (TEER):
- Consider for high-risk surgical patients
- Decision between surgery and TEER should be made by a multidisciplinary heart team 1
- TEER has shown mortality benefit at 24 months compared to medical therapy alone 2
Special Considerations
Asymptomatic Patients
- Early detection and assessment are crucial
- Best outcomes are obtained in asymptomatic patients operated on in advanced repair centers with low operative mortality (<1%) and high repair rates (≥80-90%) 3
Severe Symptomatic MR
- Delaying intervention until symptoms are severe or LV dysfunction is irreversible leads to poor outcomes 1
- Surgery is the only treatment proven to improve symptoms and prevent heart failure 3
Elderly Patients
- Nearly 10% of the population aged 75 and older has MR
- Many elderly patients are declined for open-heart surgery due to age and comorbidities
- Percutaneous treatment options (TEER) provide an alternative with encouraging results 4
Potential Pitfalls
- Inadequate assessment of MR severity can lead to incorrect treatment decisions
- Failure to optimize medical therapy before considering intervention for secondary MR
- Not referring patients to experienced centers can lead to poor outcomes 1
- Delayed intervention in primary MR can result in irreversible LV dysfunction and worse outcomes
Emerging Approaches
Percutaneous, catheter-based mitral valve repair is evolving as a valuable alternative to surgery, especially for critically ill patients 5. The COAPT trial demonstrated significant clinical benefit from TEER in carefully selected patients with secondary MR, though patient selection is crucial as shown by the contrasting results of the MITRA-FR trial 6.