Mitral annular disjunction of degenerative mitral regurgitation: 4D evaluation and implications for mitral repair

Abstract

We aimed to assess mitral valvular/annular/ventricular dynamics in mitral valve prolapse (MVP) stratified by mitral annular disjunction (MAD) presence, in the context of mitral surgery. In 61 patients (62 ± 11 years; 25% women) with MVP and severe mitral-regurgitation undergoing mitral-surgery between 2009-2016, 2D transthoracic and 4D-transesophageal echocardiographic characteristics and left ventricular (LV) dimensions/dynamics were analyzed, stratified by to MAD presence, pre and post-surgery. MAD (8 ± 3 mm) was diagnosed in 27 (44%) patients [ERO of 0.50(0.36–65)cm 2 ], more frequently in bileaflet MVP (52 vs.19%, P = 0.007), involving consistently P2 ( P = 0.03). MAD displayed larger diastolic annular area (1646 ± 410 vs. 1380 ± 348 mm 2 , P = 0.008), circumference (150 ± 19 vs. 137 ± 16 mm, P = 0.005) and intercommissural diameter (48 ± 7 vs. 43 ± 6 mm, P = 0.03) vs. no-MAD. Dynamically, early-systolic annular contraction and saddle shape accentuation were unaffected but mid- and late-systolic excess inter-commissural diameter, annular area and circumference enlargement were associated with MAD (all P < 0.0001). MAD was also associated with dynamically larger prolapse volume and height ( P ≤ 0.007), with larger leaflet area (2053 ± 620 vs. 1692 ± 488 mm 2 , P = 0.01). LV diastolic dimensions were unaffected by MAD (all P > 0.07). However, despite similar ejection fraction (65 ± 5 vs. 62 ± 8%, P = 0.1), systolic basal posterior thickness was increased in MAD (19 ± 2 vs. 15 ± 2 mm, P < 0.001). After mitral repair, MAD disappeared, and LV diameters/wall-thickness showed no difference in MAD vs. no-MAD (all P > 0.50) ( Fig. 1 ). MAD is frequent in MVP, mostly associated with bileaflet/deep MVP and compounds profound annular alterations. MAD myocardial/annular slippage masquerades stronger LV function without benefit post-surgery. Hence, MAD valvular/ventricular alterations warrant careful detection and interpretation.