Primary/anatomic MR commonly occurs with abnormalities of which valve structure?

Primary/anatomic MR commonly occurs with abnormalities of which valve structure?

• A. annulus
• B. leaflets
• C. chordae tendineae
• D. papillary muscles

Answer: (B)

Mitral regurgitation that is primary (anatomic) reflects a problem inside the valve itself. The most common structural abnormality is in the mitral leaflets. Degenerative changes, especially myxomatous degeneration, make the leaflets thickened, redundant, or prolapsing, so they don’t coapt tightly during systole and blood leaks back into the left atrium. Other components like the annulus, chordae tendineae, or papillary muscles can influence MR, but they’re more often involved in secondary (non‑organic) scenarios where the problem isn’t primarily the leaflets themselves. Papillary muscle dysfunction or rupture, for example, tends to cause MR in ischemic contexts and is not the intrinsic leaflet disease. So the leaflets are the primary site when MR is due to an intrinsic valve abnormality.

Mitral regurgitation that is primary (anatomic) reflects a problem inside the valve itself. The most common structural abnormality is in the mitral leaflets. Degenerative changes, especially myxomatous degeneration, make the leaflets thickened, redundant, or prolapsing, so they don’t coapt tightly during systole and blood leaks back into the left atrium.

Other components like the annulus, chordae tendineae, or papillary muscles can influence MR, but they’re more often involved in secondary (non‑organic) scenarios where the problem isn’t primarily the leaflets themselves. Papillary muscle dysfunction or rupture, for example, tends to cause MR in ischemic contexts and is not the intrinsic leaflet disease. So the leaflets are the primary site when MR is due to an intrinsic valve abnormality.