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The Mitral Regurgitation Index: an echocardiographic guide to severity
L Thomas1, E Foster, J I Hoffman
1Division of Cardiology, University of California, San Francisco 94143-0214, USA.
Objectives:
The purpose of this study was to develop a semiquantitative index of mitral regurgitation severity suitable for use in daily clinical practice and research.
Background:
There is no simple method for quantification of mitral regurgitation (MR). The MR Index is a semiquantitative guide to MR severity. The MR Index is a composite of six echocardiographic variables: color Doppler regurgitant jet penetration and proximal isovelocity surface area, continuous wave Doppler characteristics of the regurgitant jet and tricuspid regurgitant jet-derived pulmonary artery pressure, pulse wave Doppler pulmonary venous flow pattern and two-dimensional echocardiographic estimation of left atrial size.
Methods:
Consecutive patients (n = 103) with varying grades of MR, seen in the Adult Echocardiography Laboratory at UCSF, were analyzed retrospectively. All patients were evaluated for the six variables, each variable being scored on a four point scale from 0 to 3. The reference standards for MR were qualitative echocardiographic evaluation by an expert and quantitation of regurgitant fraction using two-dimensional and Doppler echocardiography. A subgroup of patients with low ejection fraction (EF < 50%) were also analyzed.
Results:
The MR Index increased in proportion to MR severity with a significant difference among the three grades in both normal and low EF groups (F = 130 and F = 42, respectively, p < 0.0001). The MR Index correlated with regurgitant fraction (r = 0.76, p < 0.0001). An MR Index > or =2.2 identified 26/29 patients with severe MR (sensitivity = 90%, specificity = 88%, PPV = 79%). No patient with severe MR had an MR Index <1.8 and no patient with mild MR had an MR Index >1.7.
Conclusions:
The MR Index is a simple semiquantitative estimate of MR severity, which seems to be useful in evaluating MR in patients with a low EF.
Insights
The developed Mitral Regurgitation (MR) Index offers a simple, semiquantitative method for assessing MR severity using echocardiography. This index is particularly useful for evaluating patients with reduced ejection fraction (EF).
Area of Science:
- Cardiology
- Echocardiography
- Medical Diagnostics
Background:
- Quantifying mitral regurgitation (MR) severity lacks a simple clinical method.
- The MR Index is a novel semiquantitative tool integrating six echocardiographic variables.
- These variables include Doppler-derived measurements and left atrial size estimation.
Purpose of the Study:
- To create a semiquantitative index for mitral regurgitation (MR) severity.
- The index is designed for practical clinical use and research applications.
- To validate the MR Index in patients with varying degrees of MR and reduced ejection fraction.
Main Methods:
- Retrospective analysis of 103 patients with diverse MR grades.
- Utilized six echocardiographic variables, each scored on a 0-3 scale.
- Compared the MR Index against expert qualitative assessment and quantitative regurgitant fraction.
Main Results:
- The MR Index demonstrated a significant positive correlation with MR severity in both normal and low ejection fraction (EF) groups.
- A strong correlation was observed between the MR Index and regurgitant fraction (r=0.76, p<0.0001).
- An MR Index ≥2.2 achieved 90% sensitivity and 88% specificity for identifying severe MR.
Conclusions:
- The MR Index provides a straightforward, semiquantitative estimation of MR severity.
- This index shows utility in assessing MR, especially in patients with low ejection fraction (EF).
- The MR Index is a valuable tool for clinical practice and research in mitral regurgitation.