Propensity-matched on-pump versus off-pump isolated left internal mammary artery to left anterior descending coronary artery bypass grafting analysis

Introduction Isolated surgical revascularisation of the left anterior descending (LAD) coronary artery using the left internal mammary artery (LIMA) can be performed either with or without the use of cardiopulmonary bypass and is often performed by surgeons who do not otherwise routinely perform off-pump (OPCAB) surgery, despite evidence suggesting outcomes after off-pump surgery correlate with surgeon experience. We aimed to review short and long-term outcomes after isolated LIMA to LAD. Methods Single-centre retrospective review of all consecutive patients undergoing first-time isolated in-situ LIMA to LAD between 1997 and 2024 via median sternotomy. Primary outcomes were in-hospital mortality and overall survival. Secondary outcomes were post-operative length of stay (PLOS) and post-operative complications. Propensity score matching (PSM) was performed to produce two matched groups. Results 662 patients were included (median follow-up time 84 months [29-154]). Off-pump surgery was performed in 58.2% ( n = 385). In-hospital mortality was 0.9% ( n = 6). PSM produced 275 matched pairs. Rates of post-operative stroke and blood transfusion were significantly lower in the OPCAB group, but in-hospital mortality (off-pump 0.8% vs on-pump 1.1%, p = 0.684) and overall survival (log-rank analysis p = 0.127) were similar between groups. The hazard ratio for OPCAB was 1.309 (95% confidence intervals 0.925-1.854, p = 0.127). Surgeon experience was not significantly associated with outcomes. Conclusions In this cohort, both off-pump and on-pump surgery emerged as safe treatment options for isolated LIMA to LAD surgery. Whilst OPCAB was associated with fewer complications, all other outcomes were comparable. Additional long-term studies extending beyond ten years are required to ensure these findings remain valid.