Risk-Adjusted Outcomes After Minimally Invasive Direct Coronary Artery Bypass Grafting: A Multicentre Experience

Objectives: Minimally invasive direct coronary artery bypass grafting (MIDCAB) is an appealing alternative to conventional coronary artery bypass grafting (CABG) for the treatment of the left anterior descending artery (LAD). This study aimed to evaluate risk-adjusted mortality rates following MIDCAB. Methods: All consecutive patients who underwent isolated MIDCAB were included from four international centres. Predicted 30-day all-cause mortality was calculated by the European System for Cardiac Operative Risk Evaluation (EuroSCORE II) to assess the ratio between observed and expected deaths (O-E ratio). Risk-stratified analyses of MIDCAB were performed across various risk profiles. Sensitivity analyses were performed for robotic- and non-robotic MIDCAB procedures. Overall and individual institutional learning curves were evaluated using cumulative sum (CUSUM) analyses. Results: In total, 1231 patients were included (robotic n = 945, non-robotic n = 286). Median age was 67 years (IQR, 60-74), while 17.4% of patients were female. Notably, 327 patients (26.6%) underwent MIDCAB as part of hybrid revascularization. Overall mortality rate was 0.8% (n = 10, 95% CI, 0.4-1.2%), with an O-E ratio of 0.50 (95% CI, 0.20-0.85), while the O-E ratio was 0.37 (95% CI, 0.07-0.73) and 0.79 (95% CI, 0.16-1.58) for the robotic and non-robotic groups respectively (p-for-interaction = 0.058). There was no significant interaction effect for risk categories. CUSUM analyses revealed a safe learning-curve with consistent O-E ratios <1. Conclusions: Both robotic- and non-robotic-procedure MIDCAB were associated with excellent risk-adjusted mortality rates, and O-E ratios consistently <1. These findings confirm the safety and reproducibility of the MIDCAB procedure, supporting widespread adoption of MIDCAB for the treatment of LAD-disease.