Degenerative valvular heart disease (calcific aortic stenosis, mitral prolapse)

1. Concept

Degenerative valvular disease = age-related “wear-and-tear” changes of the valves. The two classic entities are calcific aortic stenosis and myxomatous mitral valve (mitral valve prolapse).

2. Calcific aortic stenosis

• Most common degenerative valve disease and most common cause of aortic stenosis — the valvular counterpart of age-related arteriosclerosis.
• Morphology: calcified masses on the outflow side of the cusps mechanically block opening → outflow obstruction.
• Consequence: LV pressure overload → concentric LV hypertrophy (maintains output initially).
• Clinical: hypertrophied myocardium becomes ischemic → angina; classic triad also includes syncope and heart failure.

3. Myxomatous mitral valve (mitral valve prolapse, “floppy valve”)

• One/both mitral leaflets are floppy and prolapse into the LA during systole.
• Morphology: ballooned, enlarged, thick, rubbery leaflets; elongated chordae.
• Histology: attenuation of the fibrosa layer + expansion of the spongiosa with myxomatous (mucoid) material.
• Pathogenesis: intrinsic connective-tissue defect; classically Marfan syndrome (fibrillin-1 mutation); associated with scoliosis.
• Clinical: usually asymptomatic; mid-systolic click ± late murmur; risk of infective endocarditis, arrhythmia/sudden death, embolism.

💡 High-yield: Calcific aortic stenosis = most common cause of AS → pressure overload → concentric LVH → angina/syncope/HF. Myxomatous mitral valve = floppy prolapsing leaflets, fibrosa attenuation + myxoid material, linked to Marfan (fibrillin-1); mid-systolic click, IE/arrhythmia risk.