True-MAD and pseudo-MAD in consecutive patients undergoing cardiovascular magnetic resonance

Abstract Background Mitral annulus disjunction (MAD) is a controversial imaging entity with uncertain clinical significance, which has been either considered a pathological entity potentially related to mitral valve prolapse (MVP) and sudden cardiac death or, on the contrary, a benign finding in normal hearts. Cardiovascular magnetic resonance (CMR) is poised to be the ideal imaging modality to assess MAD. Recently, a distinction between pseudo-MAD, present only in systole and secondary to juxtaposition of the billowing posterior leaflet on the adjacent left atrial wall, and true-MAD, where the insertion of the posterior leaflet is clearly displaced on the atrial wall either in diastole or in systole, has been suggested. Purpose We aimed to investigate the prevalence of pseudo-MAD and true-MAD in consecutive patients undergoing clinically-referred CMR. Methods This was a single-center retrospective study including consecutive patients referred to CMR from September 2023 to November 2023. Patients with feasible MAD assessment were included. MAD was defined as a ≥1 mm displacement between the left atrial wall-mitral valve leaflet junction hinge and the top of the left ventricular wall, measured from cine-CMR images in the three long-axis views. Pseudo-MAD and true-MAD were defined according to the presence of MAD only in systole or both in systole and diastole, respectively. MVP was defined as a systolic displacement ≥2 mm of one or both mitral valve leaflets above the annulus in 3-chamber view. Results Two-hundred-ninety patients (mean age 57±18 years; 181 men, 62%) were included. MVP and MAD were respectively found in 24 (8%) and 145 (50%) patients, of which 98 (34%) with true-MAD and 47 (16%) with pseudo-MAD. In all measurements, systolic MAD (2.6±1.3 mm) resulted equal to or greater than diastolic MAD (2.2±1.1 mm). The most frequent MAD location was the inferior wall in the two-chamber view (42%), whereas the rarest one was the inferolateral wall in the three-chamber view (17%). In patients with MVP, the prevalence of MAD was higher when considering all long-axis views (22 patients, 92%), of which 50% presented with true-MAD and 50% with pseudo-MAD. The extent of pseudo-MAD and true-MAD were both greater in patients with MVP (4.2±1.5 mm and 3.0±1.6 mm, respectively) than in those without MVP (2.3±1.0 and 2.1±0.9 mm; p<0.001 and p=0.007, respectively) in all locations. At the level of the inferolateral wall, the prevalence of MAD was 71% vs. 12% (p<0.001) in patients with vs. without MVP. Conclusions The presence of true-MAD was a common imaging finding in consecutive patients undergoing CMR, thus not resulting in a distinctive abnormal feature related to MVP or sudden cardiac death. Patients with MVP showed higher prevalence and extent of true-MAD and pseudo-MAD in all locations, in line with greater degeneration of the mitral annulus. Larger studies are needed to identify potential malignant characteristics of MAD.True-MAD (A,B) and pseudo-MAD (C,D).