Regional
The wait is over: New AABB International Red blood cell transfusion guidelines for patients with acute myocardial infarction
Monica B. Pagano
University of Washington, Seattle Washington
Simon Stanworth
John Radcliffe Hospital, Oxford, United Kingdom
Acute Myocardial Infarction (AMI), remains a leading cause of morbidity and mortality globally. In managing AMI, many interventions are well studied: percutaneous coronary intervention, thrombolysis, antiplatelet therapy, statins, etc. One question, however, has long been debated: when and whether to transfuse red blood cells in AMI patients who are anemic or suffer blood loss.
While transfusion can restore oxygen‐carrying capacity, it carries risks (volume overload, allergic or febrile reactions, hemolytic complications, infection, among others), and blood is a scarce and costly resource. For many clinical and surgical conditions, guidelines recommend restrictive transfusion thresholds (e.g., hemoglobin < 7–8 g/dL), but it has been uncertain whether this approach is safe in the setting of AMI, where myocardial oxygen demand and supply imbalance are central.1
A recent AABB International clinical practice guideline has brought clarity to this issue by providing practical evidence-based recommendations.2 The guideline was informed by a meta-analysis of four randomized clinical trials (n=4311)2-5 evaluating transfusion thresholds that was performed using Cochrane methods. Critically, this meta-analysis included the two larger trials, REALITY3 and MINT4, although these trials reported inconsistent results for primary outcomes. Recommendations in the guidelines were developed by an international multidisciplinary panel that included two patient partners. The panel established outcomes of interests and minimal important differences, and followed GRADE (Grading of Recommendations Assessment, Development and Evaluation) methods to summarize evidence and formulate recommendations. The final recommendation was established by anonymous vote by the panel.
Based on an absolute risk difference of 1.2% fewer deaths with a liberal transfusion strategy, the panel suggested a liberal strategy (conditional recommendation, low‐certainty evidence) for hospitalized patients with AMI and to consider transfusion when hemoglobin is < 10 g/dL. The analysis concluded that a restrictive strategy (e.g., transfusing only when hemoglobin is 7‑8 g/dL) may increase mortality in AMI patients. On the other hand, it was noted that a liberal transfusion strategy resulted in a higher rate of severe adverse events, and overall, approximately 3.5 times more transfusions, with 34% of patients in the restrictive groups and 96% in the liberal groups receiving any transfusion. Overall, taking together the benefits (decrease mortality) and the risks (severe transfusion reactions and blood utilization), the panel placed higher value on the potential benefits of a liberal strategy in reducing mortality rather than reducing transfusion-related severe adverse events and conserving RBC units.
The guideline recommendation is conditional, and therefore this recommendation might not apply to all patients with AMI. Patients’ preferences, patient context, clinical judgment, and consideration of harms and benefits are essential to inform transfusion decisions. Transfusion decisions should not be made purely on the hemoglobin number, but on the broader clinical picture. Given the higher rate of transfusion associated adverse events associated with a liberal transfusion strategy, the panel indicated that practitioners should adopt mitigation strategies to reduce such risks, including preventing and managing volume overload, and achieving the target hemoglobin slowly.
When considering implementing this recommendation at your own institution, cardiologists, hematologists, transfusion medicine and critical care/emergency physicians should be engaged in the discussion and planning, and may wish to formulate local guidelines for quality improvement initiatives Understanding barriers to adoption (logistical, cultural, educational) will help developing strategies to facilitate uptake.7 Hospitals should perform cost‐benefit analyses, especially in resource‑limited settings, and blood services should evaluate potential increases in demand, ensuring supply, optimizing inventory and logistics. Some patients may decline transfusion or accept it only under certain conditions and shared decision making is key. Clear discussions with patients or proxies about risks and benefits; perhaps shared decision-making tools or consent forms can incorporate this recommendation.
In summary, new guidelines suggest for selected patients with AMI transfusing following a more liberal transfusion strategy in contrast to the typical restrictive policy alongside considering the full clinical picture.
References
1. Red Blood Cell Transfusion 2023 AABB International Guidelines. JAMA 2023 Nov 21;330(19):1892-1902.
2. Red Cell Transfusion in Acute Myocardial Infarction: AABB International Clinical Practice Guidelines. Ann Intern Med 2025 Aug 19. doi: 10.7326/ANNALS-25-0070
3. Effect of a Restrictive vs Liberal Blood Transfusion Strategy on Major Cardiovascular Events Among Patients With Acute Myocardial Infarction and Anemia: The REALITY Randomized Clinical Trial. JAMA 2021 Feb 9;325(6):552-560
4. Restrictive or Liberal Transfusion Strategy in Myocardial Infarction and Anemia. N Engl J Med
2023 Dec 28;389(26):2446-2456
5. Liberal versus restrictive transfusion thresholds for patients with symptomatic coronary artery disease. Am Heart J. 2013 Jun;165(6):964-971
6. Conservative versus liberal red cell transfusion in acute myocardial infarction (the CRIT Randomized Pilot Study). Am J Cardiol. 2011 Oct 15;108(8):1108-11
7. How do we leverage implementation science to support and accelerate uptake of clinical practice guidelines in transfusion medicine. Transfusion. 2025 May;65(5):799-813
