Mitral Annular Disjunction: A Serendipitous Discovery by Intraoperative Transesophageal Echocardiography

Abstract

MITRAL REGURGITATION (MR) presents as a consequence of a primary pathology of the mitral valve apparatus or secondary to ventricular dysfunction and remodeling. Most common etiology for primary MR is degenerative, with a prevalence of 1%-to-2%. 1 Freed LA Levy D Levine RA et al. Prevalence and clinical outcome of mitral valve prolapse. N Engl J Med. 1999; 341: 1-7 Crossref PubMed Scopus (717) Google Scholar Degenerative mitral valve disease is a progressive, noninflammatory, structural distortion of the valve apparatus, culminating in leaflet prolapse and regurgitation. Some of these patients present acutely due to rupture of the abnormal chordae, whereas most others present with chronic progressive MR. The spectrum of this disease is wide, ranging from fibroelastic degeneration, through forme-fruste, to Barlow's. Pathogenesis of mitral valve prolapse (MVP) has been shifting from a degenerative process involving the leaflets to an intrinsic annular abnormality. The subset in which this abnormal annular anatomy and kinetics have been demonstrated is now categorized as mitral annular disjunction (MAD). Although, primarily, MVP is characterized by leaflet and chordal involvement with secondary changes in the annulus, MAD is found to have a primary annular involvement with secondary changes in leaflets and myocardium. Typically, MAD presents as a discontinuation of the annuloatrial junction from the ventricular myocardium. It is more commonly associated with myxomatous MVP than the fibroelastic variant. 2 Essayagh B Iacuzio L Civaia F et al. Mitral annular disjunction in mitral valve prolapse: A cardiac magnetic resonance study. Arch Cardiovasc Dis Suppl. 2019; 11: 62-63 Google Scholar Similar to MVP, it has a female preponderance. 3 Putnam AJ Kebed K Mor-Avi V et al. Prevalence of mitral annular disjunction in patients with mitral valve prolapse and severe regurgitation. Int J Cardiovasc Imaging. 2020; 36: 1363-1370 Crossref PubMed Scopus (13) Google Scholar It still is unclear whether it is MAD or MVP that is the initiating trigger for MR.