Restrictive vs Liberal Transfusion Strategy After Myocardial Infarction: A Post Hoc Analysis of the MINT Randomized Clinical Trial

Importance: The decision to transfuse a patient with myocardial infarction (MI) and anemia at a higher vs lower hemoglobin threshold must consider the potential benefit of reduced risk of 30-day death or MI and the potential risk of heart failure. Objectives: To estimate bayesian posterior risk differences and posterior probabilities that a liberal vs restrictive transfusion strategy is associated with reduced risk of 30-day death or MI and whether the probabilities exceed predefined thresholds. Design, Setting, and Participants: The Myocardial Ischemia and Transfusion (MINT) trial recruited adults from April 26, 2017, to April 14, 2023, who were hospitalized with MI and anemia at 144 sites in 6 countries. Statistical analysis was performed from July 31, 2024, to February 18, 2026. Intervention: The MINT trial randomized participants to a restrictive (transfuse if hemoglobin is <7 to 8 g/dL) or liberal (maintain hemoglobin at >10 g/dL) transfusion strategy. Main Outcomes and Measures: Bayesian posterior risk differences were estimated for 30-day death or MI and for heart failure using 3 prior beliefs regarding the treatment strategies: noninformative, liberal strategy superiority, or restrictive strategy superiority. Results: The mean (SD) age of the 3504 participants was 72.1 (11.6) years and 1911 (54.5%) were men. Compared with the restrictive strategy, the risk of 30-day death or MI with the liberal strategy was 1.4% (95% credible interval, -0.8% to 3.5%) to 2.4% (95% credible interval, 0.3%-4.6%) lower, depending on prior beliefs. The probability that the liberal strategy was associated with a lower risk of 30-day death or MI ranged from 89.1% to 98.8%, and the probability that a liberal strategy was associated with at least 1 less death or MI per 100 treated was between 62.7% and 90.4%. Conversely, the risk of heart failure with the liberal strategy was 0.2% (95% credible interval, -1.6% to 1.2%) to 0.6% (95% credible interval, -2.0% to 0.8%) higher compared with the restrictive strategy, depending on prior beliefs. The probability that the liberal strategy was associated with a higher risk of heart failure ranged from 60.6% to 80.0%, and the probability that a liberal strategy was associated with at least 1 more heart failure event per 100 treated was between 13.3% and 29.3%. Conclusions and Relevance: This post hoc analysis of a randomized clinical trial of patients with MI and anemia suggests that a liberal transfusion strategy was associated with a lower risk of 30-day death or MI, outweighing the increased risk of heart failure. Consistent with guideline recommendations and according to patients' values and clinician risk assessment, a liberal transfusion strategy may be reasonable.