Mitral annular disjunction on cardiac MRI: Prevalence and association with disease severity in Loeys-Dietz syndrome

Abstract

Background: The purpose of this study was to evaluate mitral annular disjunction (MAD) on cardiac magnetic resonance imaging (MRI) in Loeys-Dietz Syndrome (LDS) and to explore its association with adverse outcomes.

Methods: In this retrospective cohort study, adult patients with LDS who underwent cardiac MRI were evaluated for MAD, aortic dimensions, and ventricular volumetry. Aortic events were defined as aortic surgery and/or dissection and severe arrhythmic events as cardiac arrest or sustained ventricular tachycardia (VT).

Results: Among 46 LDS patients (52% female, 37.2 ± 14.3 years), 17 had MAD (37%). MAD and no MAD groups were similar in age, sex, aortic dimensions and left ventricular parameters. After a clinical follow-up of 4.3 years (IQR 1.5-8.4), 3 in MAD and 4 in no MAD groups required aortic valve sparing root replacement (VSRR) and 1 in MAD developed type A dissection. Over a similar imaging follow-up period [4.1 years (IQR 2.7-9.1) vs. 3.2 years (IQR 1.0-9.0), p = 0.65], compared to baseline, increase in native aortic root size was significant only in MAD (39.4 ± 4.6 mm vs. 38.1 ± 5.3 mm, p = 0.02, 19.3 ± 2.4 mm/m2 vs. 18.7 ± 2.4 mm/m2, p = 0.01) compared to those without MAD. Patients with MAD were younger at first aortic event compared to those without (26.7 ± 11.5 years vs. 45.0 ± 14.9 years, p = 0.03). MAD distance correlated with need for VSRR, r = 0.57, p = 0.02. Two patients in the MAD group developed sustained VT. No cardiac arrest or death was observed.

Conclusion: MAD is highly prevalent in LDS, associated with progressive aortic dilatation, and aortic events at younger age. MAD may be a marker of disease severity necessitating close surveillance.

Keywords: Aortic aneurysm; Aortic dissection; Arrhythmia; Loeys-Dietz syndrome; Mitral annular disjunction; Mitral valve prolapse.