Mitral Annular Disjunction in a Large Cohort of Patients With Mitral Valve Prolapse and Significant Regurgitation

The study aimed to assess the prevalence of mitral annular disjunction (MAD) in a large cohort of unselected patients with mitral valve prolapse (MVP) and severe mitral regurgitation (MR) and identify any association between MAD and MVP etiology or mitral valve (MV) anatomy. MAD is a detachment between the ventricular myocardium and the atrial wall-posterior MV annulus (MVA), considered closely linked to Barlow’s disease (BD). Discordant data exist regarding MAD prevalence in MVP with different grades of MR. A total of 979 patients with MVP, either affected by BD or fibroelastic deficiency (FED), with clinically significant MR requiring surgery were enrolled. Pre-operative 2D transthoracic (TTE) or intraoperative transesophageal (TEE) echo examinations were retrospectively reviewed for the assessment of MAD. MVA dimensions and MV morphology at 2DTTE were also noted. The population included 637 (65%) patients with BD and 342 (35%) with FED. The overall prevalence of MAD was 16.2%: 21.8% and 5.8% in the BD and FED groups, respectively. Patients with MAD were significantly younger, had significantly larger MVA diameters (septo-lateral diameter 41[37-44] vs. 39[36-42]mm; anterolateral diameter 38[34-41] vs. 36[33-40]mm), lower incidence of chordal rupture (61.0% vs. 75.7%), higher prevalence of bileaflet prolapse (47.8% vs. 25.9%) and higher number of prolapsing scallops compared with those without MAD. In a large cohort of patients with advanced MVP and severe MR, MAD prevalence is lower than that reported in other populations of MVP. MVA detachment can be observed not only in BD patients, but also in a minority of patients with FED, suggesting that MAD might be an anatomical feature of the MVA per se, determining dilatation and distortion of the MVA, that may accelerate the progression of MV disease in patients with predisposition to it because of genetics (BD) or just because of aging (FED).