Predictors and outcomes of conversion to sternotomy in minimally invasive coronary artery bypass grafting

Background: This study aims to investigate the risk factors and surgical outcomes of conversion to median sternotomy in minimally invasive direct coronary artery bypass grafting. Methods: Between January 2017 and July 2022, a total of 274 patients (246 males, 28 females; mean age: 57.0±9.6 years; range, 33 to 81 years) who underwent conventional (n=116) or robot-assisted (n=158) minimally invasive direct coronary artery bypass grafting were retrospectively analyzed. The primary outcome measure of the study was conversion to median sternotomy, and the secondary outcome measures were operative mortality, length of intensive care unit and hospital stay. Results: Conversion to median sternotomy was required in 26 (9.5%) patients. The most common cause of conversion was intramyocardial left anterior descending artery (27.0%). Among preoperative and operative characteristics, only age was statistically significant risk factor for conversion to sternotomy (odds ratio=1.06, p=0.01). Operative mortality occurred in one patient (0.36%) patient in the entire cohort. The length of intensive care unit and hospital stay was significantly longer in patients requiring conversion to median sternotomy (p=0.002 and p<0.001, respectively). There was no significant difference in other postoperative outcomes between the two groups (p>0.05). Conclusion: Intramyocardial left anterior descending artery is the most common reason for conversion to sternotomy, and older age increases the risk of conversion. Minimally invasive coronary artery bypass grafting can be performed with satisfactory results, even if it requires conversion to sternotomy.