What is the recommended workup and management for a patient with mitral regurgitation?

Mitral Regurgitation Workup

Transthoracic echocardiography is the essential first diagnostic test to establish the diagnosis, classify MR as primary versus secondary, quantify severity, and assess left ventricular function and dimensions. 1

Initial Diagnostic Evaluation

Echocardiographic Assessment

Transthoracic echocardiography (TTE) must be performed to:

• Determine whether MR is primary (valve disease) or secondary (left ventricular disease), as this fundamentally changes management strategy 2, 3
• Quantify MR severity using multiple integrated parameters 1
• Assess left ventricular ejection fraction (LVEF), left ventricular end-systolic dimension (LVESD), and left ventricular end-diastolic dimension (LVEDD) 1
• Evaluate left atrial size and pulmonary artery pressures 1

Severity criteria for primary MR include: 1

• Vena contracta ≥7 mm
• Effective regurgitant orifice area (EROA) ≥0.4 cm²
• Regurgitant volume (RVol) ≥60 mL/beat
• Regurgitant fraction (RF) ≥50%
• Pulmonary vein systolic flow reversal

For secondary MR, lower thresholds define severity: 1

• EROA ≥0.3 cm² (or ≥0.2 cm² per some guidelines if elliptical orifice)
• RVol ≥45 mL/beat in low-flow conditions

Transoesophageal Echocardiography (TOE)

TOE should be performed when: 1

• TTE is non-diagnostic or provides insufficient information
• Pre-surgical planning is needed to assess valve anatomy and repair feasibility 1
• Intraoperative guidance is required 1

Additional Imaging

Cardiovascular magnetic resonance (CMR) is indicated when: 1

• Uncertainty exists regarding LV volumes, LVEF, or MR severity on echocardiography
• Assessment of myocardial fibrosis is needed for prognostication 1

Exercise Testing

Exercise stress testing or stress echocardiography should be performed in: 1

• Asymptomatic patients to unmask symptoms 1
• Patients with symptoms equivocal or discordant with resting MR severity 1
• Assessment of dynamic changes in mitral gradient and pulmonary artery pressure 1, 2

Biomarkers

B-type natriuretic peptide (BNP) measurement may help: 1

• Guide optimal timing of intervention in asymptomatic patients with severe MR 1
• Assess heart failure status 2

Invasive Catheterization

Cardiac catheterization is recommended when: 1

• Discordance exists between non-invasive imaging modalities 1
• Discrepancies would trigger or prevent MV intervention 1

Clinical Assessment Priorities

Symptom Evaluation

Specifically assess for: 2, 3

• Dyspnea on exertion and at rest
• Lower extremity edema and signs of fluid overload
• Exercise tolerance and functional capacity
• Presence of arrhythmias, particularly atrial fibrillation 3

Key Clinical Triggers for Intervention

In asymptomatic severe primary MR, document: 1

• New-onset atrial fibrillation (indication for surgery even if asymptomatic) 1, 3
• Pulmonary artery systolic pressure >50 mmHg 1
• LVEF ≤60% and/or LVESD ≥40 mm 1
• Progressive LV dilatation or declining LVEF on serial imaging 1

Reassessment After Medical Optimization

Critical for secondary MR: 2, 4

• Secondary MR is dynamic and changes with loading conditions, blood pressure, volume status, and heart rate 3
• Severity must be reassessed after optimized medical treatment before deciding on intervention 2, 4
• Exercise echocardiography may reveal dynamic worsening not apparent at rest 4

Surveillance Protocol

For moderate MR: 2, 3

• Clinical evaluation every 6-12 months
• Annual echocardiography 2, 3

For severe MR: 2, 3

• Clinical evaluation every 6 months
• Annual echocardiography 2, 3

For asymptomatic severe MR, monitor for: 1

• Progressive increase in LV size or decrease in LVEF on ≥3 serial imaging studies 1
• Consider complementary indices such as global longitudinal strain (GLS) 1

Common Pitfalls to Avoid

Do not delay comprehensive echocardiographic assessment when MR is suspected, as severity determines urgency and type of intervention 1

Avoid making intervention decisions in secondary MR before optimizing medical therapy, as severity may decrease substantially with appropriate heart failure management 2, 4, 3

Do not rely on a single echocardiographic parameter to grade severity; integrate multiple parameters for accurate assessment 1

Recognize that murmur intensity does not correlate with MR severity, particularly in acute severe MR where left atrial pressure elevation may result in a low-intensity murmur 3

In patients with ischemic heart disease undergoing CABG, do not overlook concomitant moderate-to-severe MR, as combined intervention may be indicated 4