Minimally invasive mitral valve repair revisited: Respect or Resect? Amidst competing risks

Mitral valve repair (MVr) remains the preferred surgical treatment for degenerative mitral regurgitation (DMR), offering superior long-term outcomes compared with mitral valve replacement (MVR). However, the optimal surgical strategy-leaflet preservation with or without neochordal implantation ('Respect') versus leaflet resection ('Resect'), or a combination thereof ('Both')-remains a matter of debate. Our aim was to compare the longer-term outcomes of these techniques in minimally invasive mitral valve surgery, in a real-world cohort encompassing anatomically complex valve pathology.

In this single-center, retrospective cohort study, 447 consecutive patients who underwent isolated MVr via right lateral mini-thoracotomy between 2006 and 2014 were included and analyzed. Patients were stratified according to the surgical repair technique ('Respect', 'Resect', or 'Both'). Primary endpoints were valve performance measures: freedom from mitral valve-related reoperation and mitral regurgitation severity during follow-up. Secondary endpoints were all-cause mortality and major adverse cardiac and cerebrovascular events (MACCE). Competing risk regression (Fine-Gray) was applied to account for death as a competing event.

Of the total cohort, 293 patients (65.5%) underwent MVr using the 'Respect' technique, 109 (24.4%) underwent leaflet resection ('Resect'), and 45 (10.1%) received a combined approach ('Both'). In-hospital mortality was 0.7%, and cerebrovascular events occurred in 0.9% of patients. At a mean follow-up of 5 years, durable mitral valve competence was present in 88.4% of patients (MR grade ≤ I). Five-year freedom from mitral valve-related reoperation was 93.3%, with no significant differences between techniques (P = 0.647). Five-year survival was 94.0%, and 5-year freedom from MACCE was 96.8%, with no statistically significant differences between techniques. Competing risk analysis (death as competing event) confirmed the absence of significant intergroup differences.

This study demonstrates that all three techniques yield equally favorable longer-term outcomes in a minimally invasive setting, extending even to anatomically complex degenerative pathologies such as Barlow's disease, bileaflet involvement, and anterior leaflet prolapse. A morphology-guided, individualized surgical approach emerges as a reliable and durable standard for the management of DMR.