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Echo Reference › Mitral Regurgitation

Echo Reference — Valve Regurgitation

Mitral Regurgitation

Qualitative and quantitative severity grading with 4-grade thresholds for primary and secondary MR. ASE integration algorithm, Carpentier functional classification, and EROA/RVol calculator by PISA method.

Algorithm Reference Tables PISA Calculator

Qualitative Parameters

MR severity assessment requires integration of qualitative, semi-quantitative, and quantitative parameters. No single parameter is sufficient. Importantly, primary (degenerative) and secondary (functional) MR have different severity thresholds for clinical decision-making — secondary MR causes adverse outcomes at lower EROA and RVol thresholds.
Parameter Mild Moderate Severe
Colour jet area Small, central, thin Intermediate Large central jet (> 40% LA area) or wall-hugging jet of any size
Vena contracta width (mm) < 3 3 – 6.9 ≥ 7
CW Doppler signal Faint, incomplete envelope Dense, partial envelope Dense, triangular (early peaking), complete envelope
Mitral inflow A-dominant or normal Variable E-dominant (E > 1.2 m/s)
Pulmonary vein flow S-dominant S-blunted Systolic reversal
Wall-hugging jets: Eccentric, wall-hugging jets (Coanda effect) are systematically underestimated by colour jet area. A wall-hugging jet reaching the back wall of the LA is at least moderate and likely severe, regardless of apparent jet area. Always measure vena contracta width and use PISA for eccentric jets.

Quantitative Parameters — Primary MR

Parameter Mild Moderate Moderate–Severe Severe
EROA (cm²) < 0.20 0.20 – 0.29 0.30 – 0.39 ≥ 0.40
RVol (mL/beat) < 30 30 – 44 45 – 59 ≥ 60
Regurgitant fraction (%) < 30 30 – 39 40 – 49 ≥ 50

Quantitative Parameters — Secondary MR

Secondary (functional) MR has lower thresholds for "severe" classification based on outcome data showing adverse prognosis at lower regurgitant volumes. The COAPT trial used EROA ≥ 0.30 cm² as entry criterion for edge-to-edge repair in secondary MR.

Parameter Mild Moderate Severe
EROA (cm²) < 0.20 0.20 – 0.29 ≥ 0.30
RVol (mL/beat) < 30 30 – 44 ≥ 45
Primary vs secondary distinction: This is clinically critical. An EROA of 0.35 cm² is moderate–severe in primary MR but severe in secondary MR — with different implications for intervention. Always classify the mechanism (Carpentier type) before applying severity thresholds.

Carpentier Functional Classification

Type Leaflet Motion Mechanism Examples
Type I Normal Annular dilatation or leaflet perforation with normal coaptation geometry AF-related annular dilatation, endocarditis (perforation)
Type II Excessive Leaflet prolapse or flail — coaptation point displaced into LA Myxomatous degeneration, chordal rupture, papillary muscle rupture
Type IIIa Restricted (systole + diastole) Organic leaflet disease with thickening, calcification, and chordal shortening Rheumatic heart disease, radiation, drug-induced (ergot, anorectic agents)
Type IIIb Restricted (systole only) Papillary muscle displacement from LV remodelling — leaflets tethered apically Ischaemic MR (regional wall motion abnormality), dilated cardiomyopathy (global tethering)
Reporting: Type I and Type II are primary (degenerative) MR — use primary MR thresholds. Type IIIb is secondary (functional) MR — use lower secondary MR thresholds. Type IIIa may be either, depending on the clinical context.

Integration Algorithm — Chronic MR

The ASE recommends a stepwise integration of qualitative and quantitative parameters. When parameters are concordant, grading is straightforward. When discordant, re-examine measurement technique and consider which parameters are most reliable in the given clinical context.

Step Action
1. Screen Colour Doppler jet area and CW signal density. If small central jet with faint signal → likely mild, may not need further quantification.
2. Semi-quantify Measure vena contracta width. VC < 3 mm → mild. VC ≥ 7 mm → severe. VC 3–6.9 mm → proceed to quantitative methods.
3. Quantify PISA method for EROA and RVol. Volumetric method (mitral vs aortic SV comparison) as a cross-check. Apply primary or secondary thresholds based on mechanism.
4. Supportive signs Pulmonary vein flow (systolic reversal → severe), mitral inflow E velocity (> 1.2 m/s → volume-loaded), LV and LA size (dilated in chronic severe MR), PASP (elevated with haemodynamic consequence).
5. Integrate If ≥ 3 parameters concordant → assign grade. If discordant → reassess technique, consider repeat measurements, and weigh the most reliable parameter for the clinical scenario.

EROA / RVol Calculator — PISA Method

EROA & RVol by PISA

EROA = (2π × r² × Valiasing) ÷ Vmax MR. Enter the PISA radius (at the aliasing boundary), aliasing velocity, and peak MR CW velocity. MR VTI is optional for RVol calculation.

EROA —
EROA Severity —
Regurgitant Volume —
RVol Severity —

Clinical Context

PISA Pitfalls

Pitfall Impact
Non-hemispheric PISA shape The PISA formula assumes a hemispheric convergence zone. Eccentric jets, wall-hugging jets, and jets near the commissures produce non-hemispheric flow convergence — EROA is underestimated. Apply an angle correction factor when the convergence zone is constrained.
Incorrect aliasing velocity Aliasing velocity should typically be set to 30–40 cm/s for a well-defined PISA hemisphere. Too high → small radius → underestimates EROA. Too low → unmeasurably large radius.
Measuring PISA radius at wrong time Measure in mid-systole when the PISA shell is most hemispheric and stable. Early or late systolic measurements may not represent the true effective orifice.
Dynamic MR orifice In secondary MR, the regurgitant orifice changes throughout systole (often larger in mid-to-late systole). A single mid-systolic PISA measurement may not capture the full regurgitant burden. Consider 3D vena contracta area as a complementary measure.
Multiple jets PISA measures one jet at a time. With multiple MR jets (e.g. bileaflet prolapse), each jet should be assessed separately or the total severity estimated using volumetric methods.

Acute vs Chronic MR

Acute severe MR (chordal rupture, papillary muscle rupture, endocarditis) presents differently from chronic MR. The LA is non-dilated (no time for remodelling), so even moderate regurgitant volumes produce marked elevation of LA pressure. The CW MR signal is often truncated (early peak, V-wave cutoff) rather than the dense holosystolic signal of chronic severe MR. Colour jet area may be misleadingly small because the high LA pressure reduces the driving gradient. Supportive signs — pulmonary oedema, pulmonary vein systolic reversal, hyperdynamic LV — are critical for recognising acute severe MR.

3D Vena Contracta Area

3D colour Doppler vena contracta area (VCA) is increasingly used as a complement to PISA, particularly for eccentric or non-circular orifices. VCA ≥ 0.40 cm² suggests severe primary MR, analogous to EROA ≥ 0.40. VCA has the advantage of measuring the actual orifice geometry rather than assuming a circular shape. It is less dependent on haemodynamic conditions than PISA but requires adequate 3D image quality.

References

  1. Zoghbi WA, et al. Recommendations for Noninvasive Evaluation of Native Valvular Regurgitation: A Report from the American Society of Echocardiography. J Am Soc Echocardiogr. 2017;30(4):303–371.
  2. Otto CM, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. Circulation. 2021;143(5):e72–e227.
  3. Vahanian A, et al. 2021 ESC/EACTS Guidelines for the Management of Valvular Heart Disease. Eur Heart J. 2022;43(7):561–632.
  4. Stone GW, et al. Transcatheter Mitral-Valve Repair in Patients with Heart Failure (COAPT). N Engl J Med. 2018;379(24):2307–2318.
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