Risk factors for blood transfusion in isolated off-pump coronary artery bypass grafting.

Aim: To examine the risk factors for transfusion during isolated off-pump coronary artery bypass grafting (OPCAB) and investigate the differential characteristics among patients receiving single versus multiple blood transfusion units. Methods: This retrospective cohort study evaluated patients undergoing isolated OPCAB at a tertiary care centre. Patients were grouped based on whether they received no transfusion, a single unit, or multiple units of blood. Clinical, demographic, and surgical variables were reviewed to assess associations with transfusion requirements. Predictive factors for single- and multiple-unit transfusion were identified through multivariable analysis. Results: Compared to patients who required no transfusion, those receiving a single or multiple units were progressively older (56.21 ± 9.1 vs. 58.23 ± 9.03 vs. 60.52 ± 11.67 years, p < 0.0001) and had a higher proportion of females (5.8% vs. 7.3% vs. 19.2%, p < 0.0001). Patients who required multiple transfusions underwent more extensive grafting, as reflected by a higher mean number of grafts (2.93 ± 0.91 vs. 3.07 ± 0.90 vs. 3.22 ± 0.85; p < 0.0001), greater drain outputs (604.26 ± 256.05 ml vs. 683.02 ± 328.25 ml vs. 840.47 ± 613.52 ml; p < 0.0001), and higher rates of re-exploration (0.1% vs. 0.6% vs. 5.4%; p < 0.0001). Multivariable analysis identified number of grafts (Odds ratio (OR) 1.58, 95% Confidence interval (CI) 1.45-1.72), female sex (OR 2.95, 95% CI 2.20-3.97), peripheral vascular disease (OR 1.74, 95% CI 1.10-2.74), elevated creatinine (OR 1.34, 95% CI 1.06-1.70), low preoperative haematocrit (OR 0.85, 95% CI 0.84-0.87), and low body mass index (OR 0.93, 95% CI 0.91-0.95) as significant predictors of multiple-unit transfusion. Similar trends were observed for single-unit transfusion, with number of grafts (OR 1.20, 95% CI 1.10-1.31), low haematocrit (OR 0.95, 95% CI 0.93-0.97), and peripheral vascular disease (OR 1.76, 95% CI 1.10-2.82) emerging as significant predictors, while associations with female sex and renal function were not statistically significant. Conclusion: A higher number of grafts, low preoperative haematocrit, low body mass index, and peripheral vascular disease were common predictors of both single- and multiple-unit transfusion during OPCAB. In addition, female sex and elevated preoperative creatinine were independently associated with an increased risk of multiple-unit transfusion. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-025-02008-4.