Abstract 13584: Mitral Leaflet Adaptation to Ventricular Remodeling in Patients With Functional Mitral Regurgitation: Three-Dimensional Analysis With Multislice Computed Tomography
Background: Little is known about whether chronic leaflet tethering causes an adaptive increase in mitral leaflet area in patients with functional mitral regurgitation (FMR). We sought to investigate the relationship between the mitral leaflet adaptation and three-dimensional (3D) mitral geometry using multislice computed tomography (MSCT). Methods: We obtained volumetric MSCT images of mitral apparatus at end-systole and end-diastole in 36 patients with FMR (24 patients with coronary artery disease with inferoposterior wall motion abnormality and 12 patients with idiopathic dilated cardiomyopathy) and 20 patients without FMR. Three-dimensional reconstruction was performed using the original software. After cropping the 3D data into 12 to 18 planes and marking the mitral annulus, leaflets, and papillary muscles (PMs), we measured the closure area (the closed leaflet surface), tenting volume and tethering distances of both PMs at end-systole. Mitral annular area and total leaflet area was measured at end-diastole. The ratio of total leaflet area to closure area was calculated to evaluate the surplus of leaflet area. Results: Tenting volume and total leaflet area were significantly increased in patients with FMR than patients without FMR (3.5±1.8 ml versus 1.5±0.5 ml, P<0.001 and 14.2±2.9 cm2 versus 11.7±2.1 cm2, P=0.002, respectively), and total leaflet area was strongly correlated with tenting volume (r=0.77, P<0.001). The ratio of total leaflet area to closure area was significantly decreased in patients with FMR than patients without FMR (1.16±0.13 versus 1.34±0.20, P <0.001), and correlated with tenting volume (r=0.53, P <0.001).
Conclusions: We demonstrated the relationship between mitral leaflet adaptation and 3D mitral geometry using MSCT. Although an adaptive increase in mitral leaflet area occurs in response to chronic leaflet tethering, insufficient leaflet adaptation was associated with excessive leaflet tethering in patients with FMR.
- © 2010 by American Heart Association, Inc.