The impact of complete versus partial preservation of the sub‐valvular apparatus on left ventricular function in mitral valve replacement

INTRODUCTION: In mitral valve replacement (MVR), sudden increases in afterload and disruption of the annular‐chordal‐papillary‐left‐ventricular wall causes left ventricular (LV) dysfunction in the early postoperative period. Preservation of the posterior mitral leaflet apparatus (MVR‐P) has a favorable outcome on LV function. However, there is paucity of data on the impact of complete preservation of the sub‐valvular apparatus (MVR‐C). OBJECTIVE: We investigated the impact of MVR‐P and MVR‐C on baseline and 3‐months postoperative LV ejection fraction (EF) and global longitudinal strain (GLS). METHODS: We retrospectively analyzed a cohort of 29 MVR‐P and 19 MVR‐C patients with complete echocardiography data at our unit, who were operated between 2008 and 2017. Between‐group changes in LVEF and GLS were compared using independent sample T‐test. RESULTS: Median age was 59 years (IQR 50–69 years). Baseline LVEF was 58% (51%– 60%). Baseline GLS was −18.4 (−21.2 to −15.5). There were no significant between‐group differences between all baseline demographics and echocardiographic markers. There was significantly higher absolute postoperative LVEF in MVR‐C patients (p = 0.029). There was also significant worsening in LVEF (p = 0.0121) and GLS (p < 0.0001) after MVR‐P and not MVR‐C, suggesting no reduction in LV function post‐MVR‐C but a reduction post‐MVR‐P. There was significantly less postoperative worsening of GLS per patient in MVR‐C group as compared to the MVR‐P group (p = 0.023), indicating better preservation of LV function. There was also a smaller decline in LVEF per patient in the MVR‐C as compared to the MVR‐P group, although not statistically significant (p = 0.23). CONCLUSION: MVR with complete preservation of the sub‐valvular apparatus shows a favorable impact on the longitudinal function of the heart at 3 months. Further studies with larger patient numbers are indicated to investigate the long‐term results of this surgical approach.