Cardiology · Medical Literature
Restrictive vs Liberal Transfusion Strategy After Myocardial Infarction: A Post Hoc Analysis of the MINT Randomized Clinical Trial.
Abstract
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. 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. 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. The MINT trial randomized participants to a restrictive (transfuse if hemoglobin is 10 g/dL) transfusion strategy. 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. 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%. 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. ClinicalTrials.gov Identifier: NCT02981407.
Clinical relevance
Anemia complicating acute myocardial infarction is a common and high-stakes clinical scenario in which the optimal transfusion threshold remains debated, creating genuine equipoise at the bedside. This Bayesian post hoc analysis of the MINT RCT — the largest trial to date addressing this question across 3,504 patients at 144 international sites — provides probabilistic, clinically interpretable estimates to guide transfusion decisions. The findings are immediately relevant to cardiologists, intensivists, and hospitalists who must weigh ischemic risk reduction against heart failure risk in this vulnerable population.
Key findings
1. A liberal transfusion strategy (target hemoglobin >10 g/dL) was associated with a 1.4% to 2.4% absolute reduction in 30-day death or MI compared with a restrictive strategy (transfuse if hemoglobin <7–8 g/dL), depending on prior belief assumptions (95% credible intervals: −0.8% to 3.5% and 0.3% to 4.6%, respectively). 2. The posterior probability that the liberal strategy reduces 30-day death or MI ranged from 89.1% to 98.8% across the three prior belief models (noninformative, liberal-superiority, and restrictive-superiority priors). 3. The probability that the liberal strategy prevents at least 1 death or MI per 100 patients treated ranged from 62.7% to 90.4%, indicating a clinically meaningful NNT signal favoring liberal transfusion. 4. The liberal strategy was associated with a 0.2% to 0.6% higher absolute risk of heart failure compared with the restrictive strategy (95% credible intervals: −1.6% to 1.2% and −2.0% to 0.8%, respectively), with the direction of effect dependent on prior beliefs. 5. The posterior probability that the liberal strategy increases heart failure risk ranged from 60.6% to 80.0%, and the probability of at least 1 excess heart failure event per 100 treated was only 13.3% to 29.3% — substantially lower than the corresponding ischemic benefit probabilities. 6. The study population had a mean age of 72.1 years (SD 11.6), with 54.5% men, reflecting the elderly, real-world MI-with-anemia cohort seen in clinical practice.
Practice implications
For patients hospitalized with acute MI and concurrent anemia, a liberal transfusion strategy targeting hemoglobin >10 g/dL should be considered the default approach, as the Bayesian evidence consistently demonstrates a higher probability of reducing 30-day mortality and reinfarction than of provoking heart failure — particularly in patients without advanced decompensated heart failure or volume overload at baseline. Clinicians should engage in individualized shared decision-making, weighing each patient's ischemic burden, left ventricular function, and volume status, consistent with current guideline recommendations that already permit a liberal threshold in MI patients. Prospective monitoring for signs of pulmonary congestion during transfusion remains prudent, given the non-negligible posterior probability of heart failure harm, but should not routinely preclude transfusion in this high-risk ischemic context.