What are the echocardiographic criteria for assessing Mitral Regurgitation (MR)?

From the Guidelines

Echocardiographic assessment of Mitral Regurgitation (MR) severity should be based on a comprehensive evaluation of multiple parameters, including regurgitant jet characteristics, vena contracta width, proximal isovelocity surface area (PISA), effective regurgitant orifice area (EROA), regurgitant volume, and regurgitant fraction, with severe MR typically characterized by a vena contracta width ≥0.7 cm, EROA ≥0.4 cm² for primary MR or ≥0.2 cm² for secondary MR, regurgitant volume ≥60 mL, and regurgitant fraction ≥50% 1.

When assessing MR, several key parameters should be evaluated, including:

• Regurgitant jet characteristics
• Vena contracta width
• Proximal isovelocity surface area (PISA)
• Effective regurgitant orifice area (EROA)
• Regurgitant volume
• Regurgitant fraction

The mechanism of MR should also be assessed using Carpentier's classification:

• Type I (normal leaflet motion)
• Type II (excessive leaflet motion/prolapse)
• Type III (restricted leaflet motion)

Additionally, evaluation for left atrial and ventricular enlargement, pulmonary hypertension, and right ventricular function is crucial as these findings impact clinical decision-making. Comprehensive assessment requires integration of multiple parameters as each has limitations, and 3D echocardiography can provide additional valuable information about valve morphology and regurgitant orifice geometry 1.

It is essential to consider the clinical context and potential factors that may influence MR severity, such as blood pressure, LV preload, and afterload reduction 1. The most recent and highest quality study 1 provides the best guidance for echocardiographic assessment of MR, and its recommendations should be prioritized in clinical practice.

Key points to consider in the assessment of MR severity include:

• Color Doppler can often overestimate MR, especially with high blood pressure, high LV systolic pressure, or peak velocities ≥ 6.0 m/s
• Color Doppler can also underestimate MR severity, especially with high LA pressures, low LV ejection fraction, or large LA/LV volumes
• Adjunctive criteria, such as a dense triangular CW Doppler profile, a well-aligned CW MR jet velocity <4.5 m/s, and systolic PV flow reversal, can support the diagnosis of severe MR 1.

From the Research

Echocardiographic Criteria for Assessing Mitral Regurgitation (MR)

The assessment of Mitral Regurgitation (MR) severity and etiology is crucial for determining the best course of treatment. Echocardiography plays a central role in this assessment, utilizing various modalities and methods to evaluate the mitral valve apparatus and left ventricular function.

• Echocardiographic evaluation of MR involves a systematic analysis of the mitral valve apparatus, including the mitral annulus, mitral valve morphology, mitral valve motion, subvalvular apparatus, papillary muscles, and left ventricular wall 2.
• The Carpentier classification is used to diagnose the mechanism of MR, which can be degenerative, rheumatic, ischemic, or functional 2, 3.
• Transthoracic echocardiography (TTE) with harmonic imaging is usually sufficient for a comprehensive assessment of MR, but transesophageal echocardiography (TEE) may be necessary if TTE is inadequate or as an intraoperative procedure 2.
• Real-time 3D echocardiography can provide additional information on mitral valve morphology and function, and may become a standard tool in the evaluation of MR in the future 2, 3.
• Quantitative Doppler echocardiography methods, such as flow convergence (EROA-PISA) and vena contracta width (VCW), can be used to assess MR severity, with EROA-PISA being a strong determinant of severe MR 4.
• Other echocardiographic parameters, such as regurgitant jet area (JA/LAA), systolic pulmonary venous flow reversal (SPVFR), and mitral E-wave velocity, can also be used to evaluate MR severity, but may have varying degrees of reliability 4.

Echocardiographic Modalities and Methods

Various echocardiographic modalities and methods can be used to assess MR, including:

• 2D and 3D echocardiography 5, 3
• Strain imaging 5
• Stress echocardiography 5
• Artificial intelligence (AI) applications 5
• Color Doppler mapping 4
• Quantitative Doppler echocardiography 4

Clinical Applications

Echocardiographic assessment of MR is essential for:

• Diagnosing the mechanism and etiology of MR 2, 3
• Quantifying MR severity 4
• Evaluating left ventricular function and morphology 2, 3
• Guiding treatment decisions, including percutaneous mitral valve repair 5
• Monitoring disease progression and response to treatment 5, 6