Characteristic of myocardial work in mitral valve prolapse with versus without mitral annular disjunction: A propensity-matched study.

Background: Mitral annular disjunction (MAD) tends to coexist with mitral valve prolapse (MVP) and mitral regurgitation (MR), and is also highly associated with arrhythmias. Myocardial work (MW) analysis is dedicated to estimate myocardial performance by integrating strain analysis and afterload. We aimed to use MW analysis to investigate the cardiac remodeling and dysfunction in MAD, particularly the damage of some segments, and to enhance the understanding of the correlations between MW parameters and VAs within MVP patients.

Methods: A total of 22 consecutive MVP patients with MAD (MAD+) and 44 consecutive MVP patients without MAD (MAD-) (50 ± 11yeas; 18% females) were screened by propensity score matching (PSM), and were divided into subgroups based on MR severity (MR+: Grade 2+; MR-: ≤1), GWI median (GWI ≤ 2079.5 mmHg%; GWI>2079.5 mmHg%), as well as the presence of VAs (VAs+; VAs-). MW parameters consist of global work efficiency (GWE), global work index (GWI), global constructive work (GCW) and global wasted work (GWW).

Results: The MAD+ patients had larger LVEDD and LAVI, as well as lower GWE, GWI, and GCW (all P<0.05) compared to the MAD- patients, regardless of similar GLS and regurgitant volume(both P>0.05). When categorized by MR severity, GWI (P = 0.049) and GCW (P = 0.040) were diminished in the MR-MAD+ group. The regional analysis showed MAD+ patients had decreased MW index in the basal (posterior and inferior) and mid (posterior and inferior) segments. Multivariate linear regression showed MAD phenotype, but not MR severity, was independently associated with diminished GWE, GWI, and GCW (all P<0.05). When divided by GWI median, MAD phenotype [OR (95%CI): 5.189 (1.193-22.572), P = 0.028] was an independent predictor of decreased GCW. The receiver-operating characteristic curve identified bileaflet prolapse [AUC (95%CI): 0.664 (0.502-0.825), P = 0.045], and GWI for basal inferior [(AUC (95%CI): 0.679 (0.538-0.819), P = 0.020] as the predictors of the VAs.

Conclusion: MAD phenotype has the ability to compromise cardiac structure and function, irrespective of volume overload, as evidenced by dilated LV and impaired MW index in basal and mid segments. Excessively decreased regional MW index can identify patients with the high risk of VAs. MW analysis can be a valuable imaging marker for detecting myocardial impairment induced by MAD.