How is mitral regurgitation measured in a 2D (two-dimensional) echocardiogram?

Measurement of Mitral Regurgitation on 2D Echocardiography

Mitral regurgitation severity should be quantified using vena contracta width and the PISA (Proximal Isovelocity Surface Area) method as the primary recommended approaches, with severe MR defined by vena contracta ≥7 mm or effective regurgitant orifice area (EROA) ≥40 mm² or regurgitant volume ≥60 mL. 1

Primary Quantitative Methods

Vena Contracta Width

• Measure the narrowest portion of the regurgitant jet at the level of the mitral valve orifice in the parasternal long-axis or apical views 1
• Severe MR: vena contracta width ≥7 mm (≥6 mm for prosthetic valves) 1
• Moderate MR: 3-6.9 mm 1
• Mild MR: <3 mm 1
• This measurement is less accurate for eccentric jets 1

PISA Method (Proximal Isovelocity Surface Area)

• Calculate EROA using the formula: EROA = 2πr² × (aliasing velocity ÷ peak MR velocity), where r is the PISA radius measured from the first color alias to the mitral valve orifice 2
• Calculate regurgitant volume: RVol = EROA × VTI (velocity time integral of the MR jet from continuous-wave Doppler) 2
• Use an aliasing velocity of 30-40 cm/s with baseline shift to obtain a hemispheric PISA 1, 2
• Severe MR: EROA ≥40 mm² (≥20 mm² for secondary MR), RVol ≥60 mL (≥30 mL for secondary MR) 1

Critical pitfall: The PISA method assumes hemispheric flow convergence, which underestimates severity in secondary MR due to the crescentic shape of the proximal convergence zone 2. Single-frame measurements can significantly over or underestimate severity, especially in non-holosystolic MR 2.

Supporting Qualitative and Semi-Quantitative Parameters

Color Doppler Jet Assessment

• Do NOT rely on color flow jet area alone to quantify acute or severe MR, as it significantly underestimates severity in very severe regurgitation and is unreliable for eccentric jets 1
• Large central jet or eccentric jet adhering to and reaching the posterior LA wall suggests severe MR 1
• Presence of flow convergence zone on the LV side during systole indicates significant MR 1

Continuous Wave Doppler Signal

• Dense, triangular CW signal with early peak velocity (blunt contour) indicates severe MR with elevated LA pressure 1
• Faint or parabolic signal suggests mild MR 1

Pulmonary Vein Flow

• Systolic flow reversal is specific (but not sensitive) for severe MR 1
• Systolic blunting suggests moderate MR 1
• Systolic dominance indicates mild or no significant MR 1

Mitral Inflow Pattern

• Peak E-wave velocity ≥1.9 m/s or mean gradient ≥5 mmHg suggests severe MR 1
• Doppler velocity index (VTI mitral/VTI LVOT) ≥2.5 indicates severe MR 1

Volumetric Method (Alternative Approach)

• Calculate regurgitant volume as the difference between total LV stroke volume (from mitral inflow) and forward stroke volume (from LVOT) 1, 2
• Regurgitant fraction ≥50% indicates severe MR 1
• This method is time-consuming and requires absence of significant aortic regurgitation 1

Chamber Remodeling Assessment

Left Ventricular Dimensions

• In chronic severe MR, expect LV and LA dilatation 1
• Normal or mildly increased LV/LA dimensions suggest acute MR or non-severe chronic MR 1
• Dilated, hyperkinetic LV with unexplained findings should raise suspicion for occult prosthetic MR 1

Left Atrial Size

• LA enlargement is sensitive for chronic significant MR 1
• Normal LA size almost excludes severe chronic MR 1

Integration Algorithm for Severity Grading

Use this structured approach:

1. Measure vena contracta width in optimal views (parasternal long-axis or apical) 1
2. Calculate EROA and regurgitant volume using PISA method when feasible 1, 2
3. Assess supporting parameters: CW Doppler signal density/contour, pulmonary vein flow pattern, mitral inflow velocities 1
4. Evaluate chamber dimensions: LV and LA size relative to chronicity 1
5. Consider clinical context: symptoms, positive pressure ventilation, and hemodynamic support can significantly alter MR severity 1

When parameters are discordant: Integrate multiple methods rather than relying on a single measurement 3, 4, 5. Consider 3D echocardiography to directly measure EROA and avoid underestimation inherent to 2D PISA 2.

Role of Transesophageal Echocardiography

TOE is indicated when:

• TTE image quality is inadequate for accurate assessment 1
• Clinical suspicion of occult MR (especially prosthetic valves) despite non-diagnostic TTE 1
• Detailed valve anatomy is needed for surgical planning 1, 6
• Eccentric jets make TTE quantification unreliable 1

Common Pitfalls to Avoid

• Never use color jet area alone for severity grading, especially in acute or very severe MR 1
• Recognize that positive pressure ventilation and sedation reduce apparent MR severity 1
• Account for measurement errors in PISA radius, which are squared in the EROA calculation 2
• Do not assume hemispheric flow convergence in secondary MR, as this underestimates severity 2
• Integrate multiple parameters rather than relying on a single measurement, as no single technique is reliable enough by itself 4