Minimally invasive mitral valve surgery in a middle-income country: feasibility and learning curve in a low-volume center

INTRODUCTION: Minimally invasive mitral valve surgery (MIM-VS) has emerged as a safe alternative to conventional median sternotomy (MS), offering advantages such as faster recovery and improved cosmetic results. However, evidence regarding its implementation and learning curve in low-volume centers within middle-income countries remains limited. This study aimed to compare the clinical outcomes of MIM-VS and MS in a low-volume center in Colombia and to assess the institutional learning curve. METHODOLOGY: A retrospective study was conducted on 112 patients who underwent mitral valve surgery via MIM-VS (n = 63) or MS (n = 49) between 2015 and mid-2024. A 1:1 nearest-neighbor propensity score matching algorithm without replacement was used to minimize confounding variables. Early postoperative outcomes were compared, and the learning curve for MIM-VS was assessed using cumulative sum (CUSUM) analysis. RESULTS: After matching, outcomes were comparable between groups. MIM-VS was associated with longer cardiopulmonary bypass (125.0 vs. 77.0 min; p < 0.001) and aortic cross-clamp times (93.0 vs. 59.0 min; p < 0.001). However, patients in the MIM-VS group exhibited shorter ICU stays (1.0–3.0 vs. 2.0–3.0 days; p = 0.045). Complication rates, including mortality, paravalvular leak, and femoral vessel injury, were similar between groups. CUSUM analysis showed an initial learning phase characterized by variable operative times, which stabilized after 40 cases. Proficiency was reached after 50 cases, correlating with reduced operative times and better outcomes. Success and failure rates improved, stabilizing after case 23, reinforcing the need for structured training and experience. CONCLUSION: The implementation of MIM-VS in a low-volume center in a middle-income country is feasible, safe and non-inferior to MS. Although initially associated with prolonged operative times, procedural efficiency improves with experience without compromising patient safety. These findings support the structured adoption of minimally invasive techniques in similar resource-constrained settings committed to training and quality monitoring.