About MINT

Multiple randomized controlled trials (RCTs) have demonstrated the safety of transfusion thresholds using a lower hemoglobin concentration (restrictive transfusion strategy) compared to higher hemoglobin threshold (liberal transfusion strategy). A restrictive transfusion strategy is the standard of care in most clinical settings although guidelines recognized the need for trials in myocardial infarction where the evidence was lacking.

With the support the NHLBI, we performed a multicenter pragmatic randomized controlled trial to compare the effectiveness of a liberal or restrictive blood transfusion strategy in patients with acute myocardial infarction and anemia. The Myocardial Ischemia and Transfusion (MINT) trial randomly allocated 3504 patients with acute myocardial infarction and hemoglobin concentration less than 10 g/dL from 144 centers located in the United States, Canada, France, Brazil, New Zealand and Australia to be treated according to a liberal or a restrictive blood transfusion strategy. Patients randomized to the liberal transfusion strategy were to receive blood transfusions to maintain their hemoglobin level at or above 10 g/dL. Patients randomized to the restrictive strategy were permitted to receive a blood transfusion if the blood count was below 8 g/dL and strongly encouraged to transfuse if hemoglobin concentration was less than 7 g/dL or for symptoms of angina. The trial primary outcome was all cause mortality or adjudicated recurrent acute myocardial infarction at 30 days.

In the MINT trial, the primary outcome occurred in 295 of 1749 participants (16.9%) in the restrictive and 255 of 1755 participants (14.5%) in the liberal transfusion strategy groups, and the risk ratio (RR) from a model that included multiple imputation for incomplete follow-up was 1.15 (95% CI, 0.99 to 1.34, p=0.07). Death through 30-days occurred in 9.9% of the restrictive and 8.3% of the liberal transfusion strategy group participants (RR, 1.19; 95% CI, 0.96 to 1.47) and myocardial infarction in 8.5% and 7.2% (RR, 1.19; 95% CI, 0.94 to 1.49).

We conclude that a liberal transfusion strategy did not significantly reduce all-cause mortality or recurrent myocardial infarction. However, the MINT results suggest that a restrictive transfusion strategy may be harmful in anemic patients with acute myocardial infarction.

The results from MINT have been incorporated into four recently published guidelines evaluating transfusion thresholds in acute myocardial infarction including the 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes. Each guideline has suggested that the use of liberal strategy may be reasonable or should be considered in anemic patients with acute myocardial infarction.

The primary results of the MINT trial were published in the New England Journal of Medicine and presented as late breaker clinical trial at the American Heart Association meeting in November 2023. We anticipate publishing more than 20 papers from the MINT trial.