Abstract 14361: Inappropriate Leaflet Remodeling in Patients With Functional Mitral Regurgitation Without Significant Mitral Valve Tethering; a Three-Dimensional Transesophageal Echocardiography Study

• Published in: Circulation (New York, N.Y.) Vol. 138; no. Suppl_1 Suppl 1; p. A14361
• Main Authors: Hayashi, Atsushi, Ikenaga, Hiroki, Yoshida, Jun, Nagaura, Takafumi, Yamaguchi, Satoshi, Kamiyama, Tetsuo, Rader, Florian, Siegel, Robert, Shiota, Takahiro
• Format: Journal Article
• Language: English
• Published: by the American College of Cardiology Foundation and the American Heart Association, Inc 06.11.2018
• ISSN: 0009-7322

BackgroundMitral valve (MV) tethering plays a central role in the development of functional mitral regurgitation (FMR). However, patients with FMR without MV tethering were encountered in clinical setting. Left atrial dilatation due to chronic atrial fibrillation has been known to cause FMR. Therefore, we aimed to identify the cause of FMR without MV tethering in patients with sinus rhythm using 3D transesophageal echocardiography.MethodsWe studied 31 FMR patients with sinus rhythm and LV dysfunction (LVEF <50%) but without significant MV tethering, defined as a tenting height ≤7.7 mm. Control subjects with normal MV (n = 26) had tenting of 5.1 ± 1.3 mm. The value of 7.7 mm was derived from the mean plus 2 standard deviation. From 3D datasets, the mitral valve was divided into 11 equidistant antero-posterior planes at mid-systole. In each plane, the entire leaflet length and straight distance from annular point to coaptation point were measured (Figure 1). The entire leaflet area was obtained as the product of inter-slice distance and the sum of the entire leaflet lengths. The theoretically minimum leaflet area was also obtained by the same calculating formula with the straight distance. The ratio of leaflet areas was then obtained, which represented abnormal leaflet remodeling. Regurgitant orifice area (ROA) was measured assuming elliptical shape of the flow convergence zone by 2D color Doppler.ResultsCompared to controls, FMR had larger LV volumes, MV annular area, and tenting volume (P <0.01). MV leaflet area was correlated with MV annular area and tethering (P <0.001). A wide range of ROA (0.02 to 1.02 cm) was observed, unrelated to LV volumes, MV annular area, and MV tethering. The ratio of leaflet areas was the only determinant of ERO (R = 0.75, P <0.0001).ConclusionMV leaflets become enlarged in response to annular dilatation and MV tethering. However, abnormal leaflet remodeling may lead to significant FMR in patients without MV tethering or atrial fibrillation.