Impact of Major Bleeding and Blood Transfusions After Cardiac Surgery: Analysis From the Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) Trial
Is excess mortality retrospectively associated with bleeding after cardiac surgery attributable to bleeding, anemia, or blood transfusion?
ACUITY was an international prospective trial of patients with acute coronary syndromes. Coronary artery bypass grafting (CABG) before hospital discharge was performed in 1,491 patients. Major bleeding was adjudicated as CABG- or non-CABG-related. The relationship between CABG-related bleeding and 1-year mortality was determined using a time-updated covariate-adjusted Cox model.
CABG-related major bleeding after surgery occurred in 789 patients (52.9%); allogeneic blood product transfusions were administered in 612 patients (41.0%), including red blood cell (RBC) transfusions in 570 (38.2%, range 1-53 units), platelet transfusions in 180 (12.1%), and fresh-frozen plasma in 195 (13.1%). One-year mortality occurred in 95 patients (6.4%). RBC transfusion (but not transfusion of platelets or fresh-frozen plasma, CABG-related major bleeding per se, or nadir hemoglobin) was an independent predictor of 1-year mortality, but only after transfusion of ≥4 units (adjusted hazard ratio for death after transfusion of 1-3, 4-6, and ≥7 RBC units = 0.74, 2.01, and 5.22, respectively). Of the 95 deaths after CABG, 23 (24.2%) were attributable to CABG-related RBC transfusions.
In patients with acute coronary syndromes, RBC transfusion of ≥4 units after CABG is strongly associated with subsequent mortality. Future strategies should focus on reducing major hemorrhagic complications and RBC transfusions after CABG.
Prior retrospective studies have identified a relationship between bleeding after cardiac surgery and subsequent mortality, but it is not known whether this is attributable to bleeding itself, to anemia, or to transfusions. This study suggests that, in the specific population of patients who undergo CABG in the setting of an acute coronary syndrome, the culprit is transfusion of ≥4 units of RBCs––which was associated with both early (30-day) and late mortality, whereas mortality was not affected by bleeding without transfusion or with transfusion of platelets or fresh-frozen plasma. Transfusion thresholds were not prospectively specified in this multicenter study, and bleeding was more common among patients in whom CABG used fewer arterial grafts and in those who underwent more ancillary procedures; as such, bleeding severity at least in part reflected the patient population and surgical complexity. However, as the authors suggest, it appears prudent to concentrate efforts at minimizing bleeding associated with cardiac surgery in order to avoid the requirement for RBC transfusion.
Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery, Cardiac Surgery and Arrhythmias, Interventions and ACS
Keywords: Acute Coronary Syndrome, Erythrocyte Transfusion, Platelet Transfusion, Erythrocytes, Blood Platelets, Thoracic Surgery, Angioplasty, Blood Transfusion, Hemoglobins, Cardiology, Cardiovascular Diseases, Cardiac Surgical Procedures, Coronary Artery Bypass, Plasma, Hemorrhage
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