The Mitral Regurgitation Index: an echocardiographic guide to severity.
OBJECTIVE
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.
Thomas
L
L
Division of Cardiology, University of California, San Francisco 94143-0214, USA.
Foster
E
E
Hoffman
J I
JI
Schiller
N B
NB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D018618:Echocardiography, Doppler, Color; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015588:Observer Variation; D011237:Predictive Value of Tests; D011669:Pulmonary Wedge Pressure; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume