Impact of mitral valve repair on global and regional longitudinal strain in patients with fibroelastic deficiency versus Barlow's disease

Abstract Background Patients with degenerative mitral regurgitation (DMR) can be differentiated into fibroelastic deficiency (FED) and Barlow’s disease (BD) based on the extent and characteristics of the mitral leaflet degeneration, but also on the mitral annulus dynamics, with a systolic outward motion of the posterior annulus being a feature of BD. These characteristics have also implications for the planning of mitral valve repair when indicated, as surgery should correct and target the exact lesion underlying DMR. Better understanding of the differences in left ventricular (LV) function between FED and BD is also important, and LV global longitudinal strain (GLS) and regional strain patterns may provide relevant information on the myocardial abnormalities accompanying DMR. Furthermore, the impact of mitral valve repair on LV strain, especially at the regional level, has not yet been compared between FED and BD. Purpose To assess LV GLS and regional strain patterns in patients with FED vs. BD before and after mitral valve repair. Methods Patients with DMR undergoing mitral valve repair between 2007-2024 at two Heart Valve Centers were assessed with echocardiography before and after surgery. We excluded patients with previous cardiac surgery, coronary artery disease, other concomitant procedures than tricuspid valve repair, other than sinus rhythm at baseline and those with significant post-surgical MR (≥2+). FED was distinguished from BD based on comprehensive assessment of all segments of the mitral leaflets as well as of annular dynamics. Mitral annular disjunction (MAD) at posterior level was also identified. LV mechanics were assessed by GLS and by the distribution of regional longitudinal strain (i.e. by the ratio of each segmental strain to GLS). All patients underwent mitral annuloplasty which eventually corrected the presence of MAD. Results A total of 174 patients (36% women), 72 with FED and 102 with BD, were assessed before surgery and at a median follow-up of 14 (IQR 11-23) months. At baseline, LV GLS was higher in BD than FED, but became similar between groups after surgery (Table). In patients with BD as compared to FED, regional LV strain before surgery was higher in the inferolateral and anterolateral segments (including the regions of insertion of the papillary muscles), reflecting the abnormal hyperdynamic motion of the myocardium supporting the mitral valve apparatus and particularly its posterior part. However, after surgery no significant differences in regional strain were observed anymore among the two subtypes of DMR (Figure). Conclusions Patients with BD show higher LV GLS as well as higher strain in the lateral LV segments compared to patients with FED. Mitral valve repair, when successful in terms of reduction of mitral regurgitation and when performed with annuloplasty, eliminates these differences in LV strain between DMR subtypes, suggesting also a favourable impact on the pathological LV mechanics observed in BD.Table Figure