Myxomatous Degeneration of Mitral Leaflet: Causes and Consequences

Primary Etiology

• Myxomatous degeneration of the mitral leaflet is a primary degenerative condition characterized by intrinsic structural abnormalities of the valve tissue itself, representing the most common cause of primary mitral regurgitation in developed countries 1
• Accumulation of proteoglycans in the valve matrix causes leaflet thickening and redundancy 1

Clinical Phenotypes

• The American College of Cardiology and European Society of Cardiology guidelines recognize two distinct presentations of myxomatous degeneration: Barlow disease and Fibroelastic deficiency (FED) 2, 3

Important Clinical Distinctions

• Myxomatous degeneration must be distinguished from secondary causes of mitral regurgitation, as the valve apparatus itself is pathologic in primary mitral regurgitation 4, 1
• When mitral regurgitation jets are directed centrally or anteriorly, or when multiple jets are present, suspect myxomatous degeneration as the underlying cause 2, 3

Age-Related Patterns

• Myxomatous degeneration is the most common cause of chordal rupture in adults, followed by endocarditis, then rheumatic disease 5
• In the pediatric population, chordal rupture predominantly occurs with rheumatic carditis rather than myxomatous disease 5

Cardiovascular Consequences

• Without surgical correction, myxomatous degeneration with severe mitral regurgitation leads to progressive left ventricular dysfunction and increased mortality 1, 4
• Chronic volume overload causes left ventricular dilatation and eventual systolic dysfunction 1, 4

Critical Management Principle

• Surgery is the only treatment proven to improve symptoms and prevent heart failure in severe mitral regurgitation from myxomatous disease, with valve repair reducing mortality by approximately 70% compared to medical management alone 1