The prevalence and significance of mitral annular disjunction on clinical outcomes in patients undergoing mitral valve surgery

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Mitral annular disjunction (MAD) is a common structural abnormality involving a distinct separation of the left atrium/mitral valve annulus and myocardium continuum. MAD is commonly associated with altered mitral valve annular dynamics, increased left ventricular and mitral valve apparatus stress and potentially life threatening arrhythmias. At present there is limited data on the prevalence and significance of MAD in patients requiring mitral valve surgery. Purpose To ascertain the prevalence, extent and significance of MAD on a general cohort of patients with mitral valve disease who required mitral valve surgery. Primary outcomes included: duration of surgery, need for re-do operation (any cause), neurological and gastro-intestinal complications, cardiogenic shock and mortality. These were assessed during the surgical hospitalisation period. Methods The local cardiothoracic database within a large tertiary centre was used to identify all patients who underwent mitral valve surgery between 2013 and 2020. From this, patients who were found to have a transthoracic echocardiogram (TTE) pre and post mitral valve surgery were included. Two experienced sonographers retrospectively reviewed and analysed each TTE. The data collected included: presence, location and extent of MAD (pre and post-surgery). The local cardiothoracic database and electronic patient records were reviewed for primary outcomes. Results A total of 187 patients were included (age: 65.6 ± 13.7 years, 74.2% males). The most common reason for mitral valve surgery was mitral valve prolapse (31.6%), remaining aetiologies included functional MR, ischemic MR, infective endocarditis, rheumatic mitral stenosis and congenital abnormalities. Surgical intervention included: leaflet repair ± annuloplasty ring (57.2%), bio-prosthesis (19.8%) or mechanical prosthesis (23.0%). Pre surgery, MAD was present in 32.6% of all patients and was most commonly seen in patients with mitral valve prolapse (21.3%). In patients with MAD, the averaged MAD length was 8.4 ± 3.9mm (median 7 [IQR: 5-11]). Post-surgery, MAD was only identified in 2 patients, both of whom had mitral valve repair± annuloplasty ring. As seen in Table 1, there were no significant differences in clinical outcomes in patients with or without MAD. Conclusion MAD is common in a cohort of patients requiring mitral valve surgery. Surgical intervention is able to correct MAD in the vast majority of patients and its presence does not affect immediate post-surgical outcomes. Abstract Table 1.