Mitral annular disjunction: the boundary between normal and pathological. Results from a large multicentre National Register of the Section of Cardioradiology of the SIRM
Elisa Bruno, Milan / Italy
Author Block: E. Bruno1, A. Palmisano1, S. Dell'Aversana2, R. Faletti3, N. Galea4, M. Gatti3, C. Liguori2, S. Pradella5, A. Esposito1; 1Milan/IT, 2Naples/IT, 3Turin/IT, 4Rome/IT, 5Florence/ITPurpose: Mitral annular disjunction (MAD) is an anatomic variant characterised by the atrialisation of the mitral valve junction; its prevalence and pathological role are still debated. The aim of the study is to evaluate the incidence of MAD in a vast cohort of patients who underwent cardiac magnetic resonance (CMR), defining the correlation with morpho-functional or myocardial tissue alterations and arrhythmias.Methods or Background: Multi-center observational study involving 13 Italian hospitals. CMR from January to June 2019 were evaluated, assessing the presence of MAD, structural (prolapse, curling, regurgitation) and tissue alterations (LGE, T1, T2, ECV), volumetric and functional features, clinical suspicion, diagnosis, presence and type of arrhythmias.Results or Findings: From a total of 2611 patients (67% XX, 53 [IQR 39-65] years old), - 4% (142 patients, 65% XX, 52 [IQR39-63] year-old) had MAD. Of them, 8% underwent CMR for the suspicion of valvopathy, 5% for arrhythmias and 87% for other causes.
47/142 (33%) patients had arrhythmias, associated with valve prolapse (p=- 004) and bigger MAD length (p< 0.001).
83/142 (58%) had MAD without other cardiomyopathies, with prolapse in 43% of cases, associated with increased incidence of curling (64% vs 17%; p-value<- 001) and higher ECV values (29% vs 25%; p=0.003).
Bi-leaflet prolapse was associated to more severe MAD compared to patients with single-leaflet prolapse or without (6 vs - 5 and 4 mm; p=0.083), bigger left atrial volume (40 mL/ m2 vs 2 mL/ m2 and 27 mL/ m2; p=0.011), left ventricle volume (170 mL vs 134 and 111 mL; p< 0.001), higher rate of moderate-severe regurgitation (45% vs 6% and 0%; p< 0.001) and arrhythmias (63% vs 36%; p=0.037), without significant differences in the presence of LGE, whereas more frequent (35% vs 25% and 27%; p=0.794).
Conclusion: MAD is frequent in the population even without valvopathies. Its severity, the association with structural alterations lead to a higher risk of myocardial remodelling and arrhythmias.Limitations: Absence of follow-up data.Funding for this study: No funding was received for this study.Has your study been approved by an ethics committee? YesEthics committee - additional information: Prot. MIAMI