Evolution of Mitral Valve Prolapse: Insights From the Framingham Heart Study

Abstract

Background: Longitudinal studies of mitral valve prolapse (MVP) progression among unselected individuals in the community, including those with nondiagnostic MVP morphologies (NDMs), are lacking.

Methods and results: We measured longitudinal changes in annular diameter, leaflet displacement, thickness, anterior/posterior leaflet projections onto the annulus, coaptation height, and mitral regurgitation jet height in 261 Framingham Offspring participants at examination 5 who had available follow-up imaging 3 to 16 years later. Study participants included MVP (n=63); NDMs, minimal systolic displacement (n=50) and the abnormal anterior coaptation phenotype (n=10, with coaptation height >40% of the annulus similar to posterior MVP); plus 138 healthy referents without MVP or NDMs. At follow-up, individuals with MVP (52% women, 57±11 years) had greater increases of leaflet displacement, thickness, and jet height than referents (all P<0.05). Eleven participants with MVP (17%) had moderate or more severe mitral regurgitation (jet height ≥5 mm) and 5 others (8%) underwent mitral valve repair. Of the individuals with NDM, 8 (80%) participants with abnormal anterior coaptation progressed to posterior MVP; 17 (34%) subjects with minimal systolic displacement were reclassified as either posterior MVP (12) or abnormal anterior coaptation (5). In comparison with the 33 participants with minimal systolic displacement who did not progress, the 17 who progressed had greater leaflet displacement, thickness, coaptation height, and mitral regurgitation jet height (all P<0.05).

Conclusions: NDM may evolve into MVP, highlighting the clinical significance of mild MVP expression. MVP progresses to significant mitral regurgitation over a period of 3 to 16 years in one-fourth of individuals in the community. Changes in mitral leaflet morphology are associated with both NDM and MVP progression.

Keywords: echocardiography; epidemiology; mitral valve.

Figure 1

Two-dimensional transthoracic echocardiogram in the parasternal long axis orientation demonstrating A) posterior mitral valve prolapse (MVP), B) abnormal anterior coaptation (AAC), and C) minimal systolic displacement (MSD). All show posterior leaflet bulging (arrows) relative to the anterior leaflet, but only MVP shows diagnostic (> 2 mm) superior leaflet displacement relative to the mitral annulus (dotted line) into the left atrium. Posterior MVP and AAC are similar with regards to an increased coaptation height and an elongated posterior leaflet. MSD shows posteriorly coapting leaflets, as seen in referents. AO, aorta; LV, left ventricle; and RV, right ventricle; Post Dis, posterior displacement.

Figure 2

Schematic echocardiographic parasternal long-axis measurements performed at Offspring Examinations 5 and at follow-up 6/8. D, annular diameter; A, P, anterior and posterior leaflet projections onto the annulus; C, coaptation height = P/D; LVID, left ventricular internal diameter; AO, aorta; LV, left ventricle. On the left an example of a referent with posterior leaflet coaptation (C = 25–30% of the annulus) and A > P. On the right, an example of abnormal anterior coaptation (AAC) with C > 40% of the annulus and elongated posterior leaflet.

Figure 3

Simple bivariate scatter plots demonstrating the correlation between change in mitral regurgitation jet height and A) change in anterior leaflet displacement, B) posterior leaflet displacement, and C) left ventricular end-systolic internal diameter (LVIDs) from Offspring Examination 5 to 6/8. Anterior displacement = 0 in panel A denotes participants with posterior leaflet involvement only. Shaded area represents 95% confidence intervals, dotted lines denote 95% prediction limits.