This is a single center retrospective study of patients who underwent off pump coronary artery bypass surgery between 2016.11~2023.05. From this patient group, preoperatively non-anemic patients were selected and were divided into 2 cohorts according to their preoperative iron status; iron replete and iron deficient. These two cohorts were compared to evaluate the effect of preoperative iron deficiency on patient outcomes.

The primary end point was the occurrence of composite morbidity/mortality end points which were: in hospital mortality, acute kidney injury (AKI), stroke, deep sternal infection, hemostatic reoperation, prolonged mechanical ventilation of more than 24hours, delirium and postoperative myocardial infarction. Occurrence of any one of these outcomes counted as primary end point met. Secondary outcome was to evaluate and compare hemoglobin recovery of iron replete and deficient patients until one year after surgery.

Inclusion Criteria:

• Patients who received off pump coronary artery bypass surgery (OPCAB) between 2016.11.01-2023.05.31

Exclusion Criteria:

• preoperative anemia (male Hb <13g/dL, female Hb<12g/dL)
• emergency surgery
• redo-off pump coronary artery bypass surgery
• minimally invasive coronary artery bypass surgery
• OPCAB in conjunction with other cardiac surgical procedures (e.g. valve surgery, graft replacement surgery of the aorta)
• intraoperative on pump conversion
• lack of sufficient preoperative data (ferritin, transferrin saturation, C-reactive protein) to determine iron status
• administration of intravenous iron within 4 weeks or parenteral iron of more than 2 weeks prior to surgery
• enrollemnt in other clinical studies

Non-anemic patients who underwent off pump coronary artery bypass surgery