Defining the learning curve of multi-vessel MIDCAB using CUSUM analysis.

Area of Science:

• Cardiovascular Surgery
• Minimally Invasive Cardiac Surgery

Background:

• Minimally invasive direct coronary artery bypass (MIDCAB) offers an alternative to conventional coronary artery bypass grafting.
• Adoption of multi-vessel MIDCAB is limited by technical complexity and a steep learning curve.
• Objective data on the multi-vessel MIDCAB learning curve are scarce.

Purpose of the Study:

• To objectively define and characterize the learning curve for multi-vessel minimally invasive direct coronary artery bypass (MIDCAB).
• To evaluate perioperative and postoperative outcomes across different phases of the learning curve.

Main Methods:

• Retrospective analysis of 169 consecutive patients undergoing multi-vessel MIDCAB (January 2020 - December 2025).
• Cumulative sum (CUSUM) analysis was used to define learning curve phases.
• Comparison of outcomes across identified learning phases.

Main Results:

• CUSUM analysis revealed three learning phases: initial (1-48), transition (49-107), and proficiency (108-169).
• Surgical experience correlated with significant reductions in cardiopulmonary bypass time, aortic cross-clamp time, and operative duration.
• Conversion to open surgery decreased, while in-hospital mortality and major complications remained low and stable.

Conclusions:

• Multi-vessel MIDCAB demonstrates a substantial learning curve, quantifiable by CUSUM analysis.
• Surgical proficiency requires a significant case volume, underscoring the importance of performance monitoring.
• These findings offer benchmarks for centers developing multi-vessel MIDCAB programs.