Background: Mitral annular disjunction is a structural abnormality of the mitral annulus fibrosus and is pathologically defined by a separation between the atrial wall-mitral valve junction and the left ventricular attachment. Mitral annular disjunction can cause hypermobility of the mitral valve apparatus and is often associated with mitral valve prolapse (MVP). The aim of this study was to investigate the frequency and characteristics of mitral annular disjunction in the patients referred to an echocardiography laboratory and to compare these with previously reported pathological data.
Methods and results: We retrospectively studied 1439 patients (mean age 65 ± 17 years, 58% male) referred to our echocardiography laboratory from 6 January 2014 to 31 March 2014. The echocardiographic parameters were compared between the patients with and without mitral annular disjunction. There were 125 cases (8.7%) with mitral annular disjunction, of which 15 (12%) also had MVP. The number of MVP patients in the group with mitral annular disjunction was significantly larger than in the group without mitral annular disjunction (p < 0.0001). The grade of mitral regurgitation was not significantly different between the two groups.
Conclusions: Mitral annular disjunction was detected not only in patients with a myxomatous mitral valve but also in normal cases. The number of MVPs was significantly larger in patients with mitral annular disjunction than patients without mitral annular disjunction. Further investigation is needed to clarify the clinical significance of the mitral annular disjunction detected by routine echocardiography.
Keywords: Mitral annular disjunction; Mitral regurgitation; Mitral valve prolapse; Pathology; Transthoracic echocardiography.