Predictive Factors for Progression of Mitral Regurgitation in Asymptomatic Patients With Mitral Valve Prolapse

Risk factors predicting progression from low grade to severe mitral regurgitation (MR), which is a guideline criterion for surgical intervention, remain unknown. We hypothesized that abnormalities of cardiac structure and function may predict progression in MR severity. We followed 82 asymptomatic mitral valve prolapse (MVP) patients (65 ± 12 years, 51% men) with mild or moderate MR (36 mild, 46 moderate, mean LVEF: 62%), without significant co-morbidities. We examined clinical findings and 13 echo measurements. The primary end point was progression to severe MR. In a mean follow-up period of 4.5 ± 2.7 years, mortality and heart failure development were similar for mild and moderate MR. No mild MR patient progressed to severe, but 23 moderate MR patients (50.0%) progressed to severe with 9 patients (39.1%) who underwent surgery. No clinical variables were predictive for progression. Only mean mitral annulus diameter (apical 4 and 2 chamber) was predictive for progression to severe MR (hazards ratio 1.14, 95% confidence interval 1.03 to 1.26, p = 0.01). A cut-off annulus diameter of 39.6 mm had a good accuracy (area under the curve 0.78, sensitivity 100%, and specificity 63.8%) for progression to severe. In conclusion, over a 4.5-year period, 50% of asymptomatic MVP patients with moderate MR, but none with mild, progressed to severe MR. Only mitral annular dimension predicted progression of moderate to severe MR, and values >39.6 mm predicted progression accurately. Mitral annulus diameter may be of value in identifying asymptomatic MVP patients at risk of developing severe MR.