P3368Mitral annulus disjunction retrospective assessment by transthoracic and transoesophageal echocardiography in a large cohort of patients with mitral valve prolapse and significant mitral regurgitation

Abstract

Abstract Background The separation between the atrial wall-mitral valve junction and the left ventricular attachment (mitral annulus disjunction, MAD) is a recently discovered feature associated with Barlow's disease (BD). Correlations between MAD and morpho-functional alterations of the mitral valve (MV) apparatus have been described and different prevalence rates of MAD have been reported by several authors, analysing small sample size populations of patients with mixomatous MV prolapse (MVP). Purpose Aims of the study were 1) to estimate the prevalence and to assess MAD in a large cohort of patients with MVP (either BD or fibroelastic deficiency, FED) and significant mitral regurgitation with indication for surgical correction conforming to guidelines; 2) identification of any correlation between MAD and the MV anatomy, MVP aetiology and general characteristics of the study population. Methods A total of 979 patients presenting at our Centre from 2007 and 2018 with MVP and moderate-to-severe or severe mitral regurgitation were enrolled in the study. All patients underwent pre-operative transthoracic echocardiography (TTE) and 792 also intraoperative transoesophageal echocardiography (TOE). All recorded images and clips were saved in a central archive and were retrospectively analysed. MAD was defined as any distance observed between the atrial wall-MV junction and the left ventricular wall; it was evaluated in all available views and measured at end-systole. Results The overall population included 630 patients (64.4%) affected by BD and 349 (35.6%) with FED. Assessing off-line images from TTE and/or TOE, MAD was identified in 161 (16.4%) patients, respectively 21% and 8% in the BD and FED subgroups. Maximal MAD distance measured 6.6±2.2 mm at TTE and 6.7 mm ± 2.2 mm at TOE. Comparing MVP patients with and without MAD, it emerged that MAD was associated with younger age (60±14 vs 64±13 years, p<0.001) and slightly lower BMI (23.9±3.6 vs 24.5±3.6 kg/cm2, p=0.045). As concerns the MV apparatus, the presence of MAD showed a median larger MV annulus (medio-lateral diameter 41.0 [37.0–44.0] vs 39.0 [36.0–42.0] mm, p=0.001; antero-posterior diameter 38.0 [34.0–41.0] vs 36.0 [33.0–40.0] mm, p=0.001), greater incidence of bileaflet MVP (47.8% vs 25.9%, p<0.001) and mixomatous aetiology (82.0% vs 60.9%, p<0.001) and a lower prevalence of chordal rupture (61.5% vs 75.7%, p<0.001). Conclusion MAD significantly correlates with specific anatomical MV characteristics. Its prevalence results to be lower than reported in previous studies performed in different clinical contexts. In MVP population with surgical indication, MAD is clearly associated to BD, but it is also observed in a minority of patients with FED Acknowledgement/Funding None