The impact of leaflet resection versus leaflet preservation on left ventricular reverse remodelling after mitral valve repair: insights from the UK mini mitral trial

OBJECTIVES: Mitral valve repair (MVr) promotes left ventricular (LV) reverse remodelling, and subsequent reduction in LV diameters and volumes. The effectiveness of different MVr techniques, Resect (leaflet resection) and Respect (leaflet preservation) remains debated. This study aimed to investigate the impact of 'Resect' and 'Respect' techniques on LV reverse remodelling, primarily assessed by changes in indexed LV end-systolic diameter (ILVESD) post-MVr. METHODS: Data were drawn from the UK Mini Mitral Trial, which randomised 330 patients to MVr via mini-thoracotomy or median-sternotomy. This subanalysis included patients with isolated posterior leaflet prolapse, who had undergone MVr via Resect or Respect techniques. Transthoracic echocardiography was performed pre-operatively and at 12 and 52 weeks post-operatively, with all studies analysed by a core laboratory. Linear mixed-effects models compared changes in indexed LV measurements between groups. RESULTS: This subanalysis included 175 patients (36 Resect and 139 Respect). Annuloplasty was performed in all but one repair. We found no significant difference between groups in recurrent MR severity at 52 weeks postoperatively (p = 0.31). Both groups had significant improvement in ILVESD by 52 weeks (mean change from baseline - 5.6%, p < 0.001), with no difference between groups (p = 0.24). Both techniques led to significant improvements in indexed end-diastolic LV volumes and diameters, decreasing from baseline to 12 and 52 weeks. However, LV end-systolic volumes and diameters increased at 12 weeks before decreasing by 52 weeks postoperatively. CONCLUSION: No significant differences in LV reverse remodelling between Resect and Respect techniques. Both can be recommended to surgeons. Longer follow-up is needed.