What are the BSE (British Society of Echocardiography) guidelines for managing a patient with moderate mitral regurgitation (MR)?

Management of Moderate Mitral Regurgitation

For patients with moderate MR, perform clinical and echocardiographic surveillance every 1-2 years, with more frequent monitoring (yearly) if there is evidence of progressive LV dilatation or declining function. 1

Surveillance Strategy

Follow-up Intervals

• Asymptomatic moderate MR with preserved LV systolic function requires yearly clinical assessment with repeat echocardiography every 1-2 years 1
• In the context of rheumatic heart disease, moderate MR necessitates 12-monthly transthoracic echocardiography with specialist review and 6-monthly medical review 1
• If LV dimensions are progressively increasing on serial imaging, more frequent reassessment is required 1

Key Echocardiographic Parameters to Monitor

• LV ejection fraction (threshold: <60% triggers consideration for intervention) 1, 2
• LV end-systolic diameter (threshold: ≥40 mm triggers consideration for intervention) 1, 2
• Left atrial volume index (significant dilatation: ≥60 mL/m²) 1
• Consider novel measurements of LV function such as global longitudinal strain (GLS) 1

Advanced Diagnostic Considerations

When to Use Additional Imaging

• Exercise echocardiography is useful for risk stratification in patients with exercise-induced symptoms to assess dynamic worsening of MR 1, 2
• Cardiovascular magnetic resonance (CMR) should be utilized when echocardiographic measurements are ambiguous or uncertain regarding LV volumes and LVEF 1, 2
• Holter monitoring may be valuable for detecting arrhythmias 1

Biomarker Monitoring

• Consider B-type natriuretic peptide (BNP) levels to help guide optimal timing of intervention, particularly in asymptomatic patients 1, 2

Critical Pitfalls and Clinical Pearls

Risk of Progression

• Over 50% of patients with less-than-severe MR due to mitral valve prolapse develop either worsening MR or de novo LV dysfunction during follow-up 3
• Importantly, 21% of patients develop new LV dysfunction even when MR severity remains stable 3
• Larger LV end-diastolic dimensions and greater diastolic septal thickness predict progression of MR severity 3

When to Escalate Monitoring

• Patients with dynamically changing LV parameters or those close to intervention thresholds require closer monitoring 1
• Progressive increase in LV size or decrease in EF on ≥3 serial imaging studies should prompt consideration for early intervention 1
• New-onset atrial fibrillation or pulmonary artery systolic pressure ≥50 mmHg in the setting of moderate MR warrants reassessment 1

Medical Management Considerations

Primary MR

• β-blockers appear to lessen MR severity, prevent deterioration of LV function, and improve survival in asymptomatic patients with moderate to severe primary MR 4
• ACE inhibitors and ARBs reduce MR severity, especially in asymptomatic patients 4
• Caution: In hypertrophic cardiomyopathy or mitral valve prolapse, vasodilators can paradoxically increase MR severity 4

Secondary MR

• Guideline-directed medical therapy is mandatory and includes ACE inhibitors/ARBs, β-blockers, and mineralocorticoid receptor antagonists 2

Specific Populations Requiring Attention

Mitral Valve Prolapse with Moderate MR

• These patients exhibit early cardiac chamber remodeling even with less than moderate MR 5
• Presence of premature ventricular contractions (PVCs) is associated with LV end-systolic diameter ≥40 mm 5
• Isolated posterior leaflet prolapse is associated with higher risk of MR progression 5