OBJECTIVES This study was performed to define the rates and determinants of
progression of organic mitral regurgitation (MR).
BACKGROUND Severe MR has major clinical consequences, but the rates and det
erminants of progression of the degree of regurgitation are unknown. Quanti
tative Doppler echocardiographic methods allow the quantitation of regurgit
ant volume (RVol), regurgitant fraction (RF) and effective regurgitant orif
ice (ERO) to define progression of MR.
METHODS In a prospective study of. MR progression, 74 patients had two quan
titative Doppler echocardiographic examinations of MR (with at least two me
thods) 561 +/- 423 days apart without an intervening event.
RESULTS Progression of MR was observed, with increase in RVol (77 +/- 46 ml
vs. 65 +/- 40 ml, p < 0.0001), RF (47 +/- 16% vs. 43% +/- 15%, p < 0.0001)
, and ERO (50 +/- 35 mm(2) vs. 41 +/- 28 mm(2), p < 0.0001). Annual rates (
95% confidence interval) were, respectively, 7.4 ml/year (5.1, 9.7), 2.9%/y
ear (1.9, 3.9) and 5.9 mm(2)/year (3.9, 7.8). However, wide individual vari
ation was observed, and regression and progression of RVol >8 ml was found
in 11% and 51%, respectively. In multivariate analysis, independent predict
ors of progression of RVol were progression of the lesions, particularly a
new flail leaflet (p = 0.0003), and progression of mitral annulus diameter
(p = 0.0001). Regression of MR was associated with marked changes in afterl
oad, particularly decreased blood pressure (p = 0.008). No significant effe
ct of treatment was detected.
CONCLUSIONS Organic MR tends to progress over time with increase in volume
overload (RVol) due to increase in ERO. Progression of MR is variable and d
etermined by progression of lesions or mitral annulus size. These data shou
ld help plan follow up of patients with organic MR and future intervention
trials. (J Am Coll Cardiol 1999;34:1137-44) (C) 1999 by the American Colleg
e of Cardiology.