Side-Clamping Versus Single Cross-Clamping in On-Pump CABG: Impact on Early Hematologic Outcomes and Blood Conservation

Aortic manipulation and prolonged ischemia during cardiopulmonary bypass remain major drivers of perioperative complications. Optimizing clamping strategies is crucial to minimize iatrogenic blood loss and improve recovery profiles within a Patient Blood Management (PBM) framework. Objectives: This study aimed to evaluate the impact of two different aortic clamping strategies—single cross-clamping versus side-clamping—on early hematologic outcomes within a Patient Blood Management (PBM) framework in patients undergoing on-pump coronary artery bypass grafting (CABG). Methods: In this retrospective cohort study, 265 patients who underwent elective isolated 3-vessel on-pump CABG between January 2019 and April 2025 were analyzed. Patients were divided into two groups: the Side-Clamp group (n = 132), where proximal anastomoses were performed under partial occlusion after releasing the main cross-clamp, and the Single Cross-Clamp group (n = 133), where all anastomoses were completed during a single arrest period. The primary outcomes were postoperative hemoglobin (Hb) drop and 24-h chest tube drainage. Results: The side-clamp technique was associated with significantly shorter cardioplegic arrest times (34.5 ± 3.7 vs. 52.0 ± 3.9 min; p < 0.001). Key findings revealed that the postoperative hemoglobin drop was significantly lower in the side-clamp group (1.9 ± 0.4 g/dL vs. 2.1 ± 0.4 g/dL; p = 0.005). Notably, the side-clamp group also exhibited significantly lower 24-h chest tube drainage (123.4 ± 28.3 mL vs. 131.0 ± 27.4 mL; p = 0.027). Multivariate linear regression analysis, adjusting for age, sex, and CPB time, confirmed the side-clamp technique as an independent predictor of superior hemoglobin preservation (β = −0.115, p = 0.009). No significant differences were observed regarding the incidence of postoperative AF (13.6% vs. 15.8%; p = 0.748) or 30-day mortality. Conclusions: The side-clamp strategy is associated with modest but statistically significant reductions in postoperative hemoglobin decline and 24-h chest tube drainage. While these differences did not translate into a significant reduction in RBC transfusion or early mortality, the side-clamp technique represents a useful technical component within a broader Patient Blood Management strategy in routine on-pump CABG practice.