Primary (Organic) MR – leaflet/chordal abnormality
- Mitral valve prolapse
- Flail leaflet (chordal rupture)
- Rheumatic disease
- Endocarditis
- MitraClip/iatrogenic
Secondary (Functional) MR – annular or ventricular abnormality
- Ischemic MR (due to papillary muscle displacement after MI, usually inferior/posterior MI)
- Dilated cardiomyopathy (annular dilation, papillary displacement)
- Restrictive LV remodeling
Ischemic / Functional MR
- Typically central or posteromedial jets.
- Mechanism: LV dilation → papillary muscle displacement → tethering of leaflets → incomplete coaptation.
- Ischemic MR after inferior MI often eccentric (posterior pap muscle dysfunction causing anterior jet).
When is MR Eccentric?
- Eccentric jet (wall-hugging, Coandă effect):
- Mitral valve prolapse (classic cause)
- Flail leaflet
- Chordal rupture
- Papillary muscle rupture (acute MR)
- Central jet:
- Functional/ischemic MR
- Annular dilation
TTE Cutoffs
- Mild (Grade I)
- EROA <0.2 cm²
- RVol <30 mL
- RF <30%
- VC <0.3 cm
- Moderate (Grade II–III)
- Grade II (mild-mod): EROA 0.2–0.29, RVol 30–44, RF 30–39%, VC 0.3–0.39
- Grade III (mod-sev): EROA 0.3–0.39, RVol 45–59, RF 40–49%, VC 0.4–0.69
- Severe (Grade IV)
- EROA ≥0.4 cm²
- RVol ≥60 mL
- RF ≥50%
- VC ≥0.7 cm
- (≥3 criteria or elliptical orifice)
How to Measure
- EROA (PISA): Color Doppler → adjust Nyquist (~30–40 cm/s) → measure PISA radius (r) → Flow = 2πr² × aliasing vel → get peak MR Vmax (CW) → EROA = Flow ÷ Vmax
- RVol: RVol = EROA × MR VTI (trace CW jet)
- RF: RF = (RVol ÷ LV stroke vol) ×100% (LVSV via LVOT or volumes)
- VC: Parasternal long-axis, color Doppler, narrowest jet, avg early–mid systole.
Use ≥2–3 concordant findings; integrate with jet area, pulm vein flow, LV size.
Qualitative Assessment (CW Doppler)
- Mild: Faint, parabolic, often <4m/s
- Moderate: Denser, parabolic, ~4m/s
- Severe: Very bright/dense, triangular (late-peaking), often 5-6m/s
Qualitative Assessment (Jet Length)
- Break the LA into thirds
- Depending on how far the jet travels backwards to the LA can indicate potential severity
- A = Mild
- B = Moderate
- C = Severe
MR Severity Calculator
| Severity | EROA (cm²) | RVol (mL) |
|---|---|---|
| Mild | <0.2 | <30 |
| Mild–Moderate | 0.2–0.29 | 30–44 |
| Moderate–Severe | 0.3–0.39 | 45–59 |
| Severe | ≥0.4 | ≥60 |