An expert panel recently published a paper titled “Red Cell Transfusion Acute Myocardial Infarction: AABB International Clinical Practice Guidelines” in the Annals of Internal Medicine. The authors described the paper’s purpose as, providing guidelines for transfusing red blood cells (RBCs) in patients with acute myocardial infarction (AMI) based on the available literature and analyses of four randomized controlled trials, “of patients presenting with AMI who were assigned to two different transfusion strategies (restrictive or liberal) based on Hb concentrations or hematocrit levels before receipt of a transfusion.”
The paper explained that the, “values and preferences underlying the recommendation reflect the life-threatening context of AMI and include mortality and reduction of the risk for recurrent MI (high value), severe adverse events after RBC transfusions (high value), and conservation of the RBC supply (moderate value). Overall, the panel place[d] a higher value on the uncertain potential benefits of a liberal strategy on reducing mortality than the unequivocal benefits of a restrictive strategy in conserving RBC units and reducing transfusion-related severe adverse events.” This liberal transfusion strategy could be crucial in specific clinical situations.
The panel recommended a liberal RBC transfusion strategy for hospitalized AMI patients, “[w]hen the hemoglobin concentration is less than 10 g/dL (conditional recommendation, low-certainty evidence). A restrictive strategy of 7 to 8 g/dL may result in increased mortality in patients with AMI.” The paper noted that, “[f]or hospitalized adult patients with AMI, it is important to incorporate the clinical context (e.g., patients’ history, signs, symptoms, hemodynamic status) and patients’ preferences when weighing RBC transfusion decisions.” The authors added that, “[i]n accordance with the increased risks of severe adverse events in the liberal transfusion strategy, clinicians should consider strategies for mitigation of adverse transfusion events. Strategies include optimizing fluid status peri-transfusion, slowing transfusion rate, prescribing diuretics, achieving the target Hb more gradually, and transfusing during renal replacement therapy sessions for renal failure.”
The rationale for the recommendation was described as, “[t]he 1.2 percent overall estimated benefit in 30-day mortality exceeded the panel-defined minimal important difference (MID), supporting the potential benefit of a liberal transfusion strategy. Moreover, there was moderate-certainty evidence that the liberal strategy does not result in an important increase in mortality. A higher incidence of transfusion-related adverse events in the liberal group, in which transfusion was almost universal and participants received three times more units compared with the restrictive group, might be expected, although the difference between strategies was [l]ess than the panel’s chosen MID. Given that the panel’s perspective of considering value and preferences placed higher value on the uncertain potential benefits of a liberal strategy in reducing mortality rather than the unequivocal benefits of a restrictive strategy in conserving RBC units and reducing transfusion-related severe adverse events, the panel agreed on a conditional recommendation in favor of the higher threshold.” Such a liberal transfusion approach possibly presents unique advantages in patient outcomes.
Additional clinical considerations outlined by the authors included, “there are almost no clinical scenarios that would preclude transfusions except very rare situations of near fatal anaphylactic or hemolytic reactions or impossibility of finding compatible blood. Blood availability might be a limiting factor in some geographic areas. The panel considered the importance of implementing appropriate risk mitigation strategies in patients at risk for severe adverse reactions, such as those with circulatory overload. These approaches include[d] but are not limited to the following: risk stratification for TACO; optimizing fluid status in the peri-transfusion period; slowing the RBC infusion rate; peri-transfusion diuresis; achieving the target Hb concentration more slowly; and transfusing during renal replacement therapy for patients acutely or chronically requiring such therapy. [Additionally, the panel noted that clinicians] should adopt general approaches to mitigate the risk for anemia through the deployment of patient blood management strategies, including minimizing unnecessary blood testing, use of low-volume sample collection tubes, and early recognition and treatment of underlying causes of anemia.” Hence, embracing a liberal transfusion strategy requires careful planning.
Limitations of the guidelines include, “MID estimates based on limited direct evidence regarding patient values and preferences; [and the] guideline recommendation does not apply to patients with acute coronary syndrome or patients without AMI, for whom uncertainty about the safety of restrictive thresholds remains.” The authors stated that future research needs should, “address the optimal threshold for transfusion according to the mechanism of MI and patient-specific characteristics.” To conclude, the liberal transfusion strategy can offer pronounced benefits, though more research is needed.
Citation: Pagano, M.B., Stanworth, S.J., Dennis, J., et al. “Red Cell Transfusion in Acute Myocardial Infarction: AABB International Clinical Practice Guidelines.” Annals of Internal Medicine. 2025.