Abstract 11753: Disjunction of the Mitral Annulus Is Associated With Paradoxical Systolic Expansion and Flattening in Degenerative Mitral Valve Disease: A Real-time 3-dimensional Transesophageal Echocardiographic Study

Abstract

Introduction: Disjunction of the mitral annulus, defined as a separation between the atrial wall-mitral valve junction and the left ventricular attachment, is commonly seen on echocardiography in patients with degenerative mitral valve prolapse (MVP). Few data exists on the three-dimensional (3D) geometry of annular disjunction and its relationship with the annular dynamic function. Hypothesis: We assessed the hypothesis that annular disjunction is associated with abnormal annulus structure and function. Methods: A total of 138 subjects including 108 MVP patients (58±11years) and 30 subjects with normal MV (57±15years) were studied using real-time 3D transesophageal echocardiography. The annular circumference was examined in multiple radial planes at 10° intervals for any disjunction. The location, separation distance, and circumferential extent of disjunction were assessed. The annular area, width, and height were measured at end-diastole and end-systole. Results: Annular disjunction was evident in 61 (56%) MVP patients and 3 (10%) normal subjects (P<0.0001). Among MVP patients, disjunction is usually located adjacent to the prolapsed segments, circumferentially spanning over 79°±42° (20° to 190°) of the annulus, with the maximal separation measuring 8.7±3.8mm. Annular disjunction is associated with more prolapsed segment (2.0±1.6 vs 1.3±0.6, P=0.0021), more severe mitral regurgitation (effective regurgitant orifice area=0.64±0.49 vs 0.45±0.23cm 2 , P<0.0001), paradoxical systolic increase in annular area and decrease in height-to-commissural width ratio (AHCWR) (Figure), despite normal ventricular ejection fraction (62±5% vs 62±7%, P=0.97). Conclusions: Mitral annular disjunction is associated with decoupling of annular and ventricular function leading to paradoxical annular expansion and flattening of the annular saddle-shape during systole in patients with MVP and may require specific surgical correction.