Bilateral internal mammary artery (BIMA) grafts utilization in coronary artery bypass grafting (CABG) for diabetic patients has been limited due to concerns regarding postoperative morbidity, especially sternal wound infections (SWI). However, outcomes for BIMA grafting combined with off-pump CABG (OPCAB) in diabetic patients remain underexplored. This study aimed to compare BIMA and single internal mammary artery (SIMA) grafting outcomes in diabetic OPCAB patients. A single-center retrospective analysis was conducted on diabetes patients who underwent OPCAB with BIMA or SIMA grafts from January 2020 to December 2023. Baseline characteristics, including STS risk scores, were matched between cohorts using stabilized inverse probability treatment weighting (sIPTW). The study included 412 diabetic patients: 207 (50.2%) received BIMA and 205 (49.8%) received SIMA grafts. After sIPTW matching, 30-day mortality was identical (1.4%, p = 0.40), with comparable rates of deep (0.9% vs 0.8%, p = 0.89) and superficial sternal wound infections (4% vs 1.8%, p = 0.19). Composite complication rates (40% vs 47%
p = 0.13) and individual components such as renal injury, reoperation bleeding, stroke, and atrial fibrillation were similar between groups. Rates of overall readmission and cardiac readmission, discharge-to-home versus acute care facilities, and hospital stays longer than 7 days were comparable. Notably, BIMA showed significantly lower rates of blood transfusion (31% vs 40%
p = 0.038) and prolonged ventilation (9% vs 16%
p = 0.033) than SIMA group. In conclusion, our findings suggest that BIMA grafting combined with OPCAB may be safely used in diabetic patients despite historical concern about wound healing complications.