A Reverse Saddle Mitral Annulus Shape Explains Apparent Systolic Mitral Annular Disjunction in Mitral Valve Prolapse: a 3D Transesophageal Echocardiography Analysis.

AIMS Mitral annular disjunction (MAD) is considered an abnormal anatomical/functional feature in patients with mitral valve prolapse (MVP). Recent evidence suggests that in most cases, systolic disjunction is only apparent (Pseudo-MAD), because of altered annular dynamics, with the leaflet hinge point remaining anchored to the annulus. The aim of this study was to analyze mitral annular shape and dynamic function in patients with MVP by 3D transesophageal echocardiography (3D-TEE).

METHODS AND RESULTS Patients with MVP and ≥ grade 3 mitral regurgitation (MR) who underwent comprehensive 3D TEE evaluation were retrospectively included. Mitral annular shape and dynamic function were analyzed using 3D-TEE dataset and dedicated software. Two-hundred-twenty-five patients were included (77 with Pseudo-MAD, 14 with True-MAD). Among Pseudo-MAD, the majority (n=60, 78%), demonstrated an altered systolic annular conformation with a "reverse-saddle" shape. This reverse-saddle shape was less common in patients with No-MAD or with True-MAD (9% and 14%), who mostly exhibited a normal or flattened annular shape. Patients with Pseudo-MAD had greater degrees of valve degeneration, with longer mitral posterior leaflets (18 ± 3mm vs 15 ± 4 mm, p<0.01), larger annular diameters (systolic AP diameter 38 ± 4 mm vs 35 ± 6 mm, p<0.01; systolic and diastolic IC diameters 43 ± 5 mm vs 39 ± 6 mm and 44 ± 4 mm vs 40 ± 5 mm, respectively) and impaired sphincteric function. Pickelhaube sign and curling were common in both Pseudo-MAD and reverse-saddle shaped annulus. No differences in acute surgical outcomes were observed among groups.

CONCLUSIONS These findings provide a pathophysiological basis for the hypothesis that MAD, when evident only in systole (Pseudo-MAD), appears to be largely explained by altered annular dynamics and function, with a new identified systolic reverse-saddle shape.