From the Guidelines
The severity of mitral regurgitation (MR) can be graded using a combination of clinical evaluation, echocardiography, and other imaging modalities, with criteria including regurgitant volume, regurgitant fraction, and vena contracta width 1.
Grading Criteria
The severity can be classified into several grades, including:
- Mild: Characterized by a regurgitant volume of less than 30 mL per beat, regurgitant fraction of less than 30%, and a vena contracta width of less than 3 mm 1.
- Moderate: Characterized by a regurgitant volume of 30-59 mL per beat, regurgitant fraction of 30-49%, and a vena contracta width of 3-6 mm 1.
- Severe: Characterized by a regurgitant volume of 60 mL per beat or greater, regurgitant fraction of 50% or greater, and a vena contracta width of 7 mm or greater, often with significant left ventricular and left atrial enlargement 1.
Additional Considerations
Additional considerations for grading MR severity include:
- Color Doppler can often overestimate MR, especially with high blood pressure or high LV systolic pressure, and can underestimate MR severity with high LA pressures or low LV ejection fraction 1.
- Adjunctive criteria such as a dense triangular CW Doppler profile, dilated LA or LV with no other cause, and systolic PV flow reversal can support severe MR 1.
- Clinical context and pressure during imaging can affect MR severity assessment, and maneuvers that decrease LV preload can increase MR severity in certain conditions 1.
From the Research
Criteria for Grading Mitral Regurgitation Severity
The severity of mitral regurgitation (MR) can be graded using various criteria, including:
- Valve structure and morphology 2, 3, 4
- Cardiac remodeling and left ventricular dimensions 2, 3, 4
- Color and spectral Doppler parameters, such as jet size and characteristics 2, 5, 4
- Quantitative measurements, including effective regurgitant orifice area, regurgitant volume, and regurgitant fraction 2, 5, 3
- Proximal jet width and vena contracta 5, 4
- Left atrial width and systolic reversal 5, 4
Grading Systems
Different grading systems have been proposed, including:
- A modified scoring system that assigns points based on color Doppler jet size, central or eccentric jet, left atrial width, and proximal jet width 5
- An integrative approach that considers multiple Doppler methods and clinical data 2, 3
- The ROSE-index, a scoring index that uses 11 echocardiographic parameters to determine the severity of MR 4
Challenges and Limitations
The assessment of MR severity can be challenging, particularly in patients with intermediate or borderline severity 6