From the Guidelines
The severity of mitral regurgitation (MR) can be graded based on the effective regurgitant orifice area (EROA) as follows:
- Mild: EROA < 20 mm² 1
- Moderate: EROA between 20-29 mm² or 30-39 mm², with the latter being considered moderate-to-severe 1
- Severe: EROA ≥ 40 mm² 1
It's essential to consider these values in the context of overall clinical assessment, including symptoms and other echocardiographic parameters, such as vena contracta width, pulmonary vein flow, and left ventricular size and function 1. The grading of MR severity is crucial for determining the appropriate treatment strategy and prognosis.
Key Parameters for Grading MR Severity
- EROA: < 20 mm² (mild), 20-29 mm² or 30-39 mm² (moderate), ≥ 40 mm² (severe) 1
- Vena contracta width: < 3 mm (mild), ≥ 7 mm (severe) 1
- Pulmonary vein flow: systolic dominance (mild), systolic blunting (moderate), systolic flow reversal (severe) 1
Clinical Considerations
The severity of MR should be integrated with clinical findings, including symptoms, left ventricular function, and pulmonary pressures, to determine the best course of treatment 1. In patients with severe MR, surgical intervention may be necessary to prevent further deterioration of left ventricular function and to improve symptoms 1.
Echocardiographic Assessment
Echocardiography is a crucial tool for assessing MR severity, and multiple parameters should be used to determine the severity of regurgitation 1. The flow convergence method may underestimate the true ERO, and multiple parameters must be used to determine the severity of MR 1.
From the Research
Grading Severity of Mitral Regurgitation
The grading severity of mitral regurgitation (MR) can be evaluated using various methods, including effective orifice area (EOA). The following points summarize the key findings:
- A study published in 2006 2 proposed a scoring system for evaluating the severity of MR, which includes color Doppler jet size, central jet, LA width, and proximal jet width.
- Another study published in 2024 3 investigated the use of 3D echocardiography to quantify MR severity and found that 3D vena contracta area (VCA) correlated significantly better with MR severity than 2D proximal isovelocity surface area (PISA) method.
- A study published in 2017 4 developed a novel method for grading MR severity based on average pixel intensity (API) analysis of the continuous wave Doppler envelope and found that API correlated linearly with color Doppler, vena contracta width (VCW), and PISA-effective regurgitant orifice area (EROA).
- A study published in 2011 5 compared direct planimetry of mitral valve regurgitation orifice area by 3D transesophageal echocardiography to EROA obtained by proximal flow convergence method and VCA determined by color Doppler echocardiography and found high correlation between the methods.
- A study published in 2024 6 validated the use of 3D VCA to quantify MR severity in patients with mitral valve prolapse and defined cutoff values for severity grading, including an optimal cutoff value of 0.45 cm2 for predicting severe MR.
Effective Orifice Area (EOA) Cutoff Values
The following cutoff values for EOA have been reported:
- A study published in 2024 6 found an optimal cutoff value of 0.45 cm2 for predicting severe MR using 3D VCA.
- The same study found that a cutoff of 0.50 cm2 predicted an EROA-PISA of 0.40 cm2.
- A study published in 2011 5 found that the correlation between AROA and EROA was higher in an EROA ≥0.2 cm2 (r = 0.95) than in an EROA <0.2 cm2 (r = 0.60).
Comparison of Methods
The following comparisons between methods have been reported:
- A study published in 2024 3 found that 3D VCA correlated significantly better with MR severity than 2D PISA method.
- A study published in 2017 4 found that API correlated linearly with color Doppler, VCW, and PISA-EROA.
- A study published in 2011 5 found high correlation between direct planimetry of mitral valve regurgitation orifice area by 3D transesophageal echocardiography and EROA obtained by proximal flow convergence method and VCA determined by color Doppler echocardiography.