A liberal transfusion strategy aimed at maintaining hemoglobin at or above 10 g/dl in patients with acute myocardial infarction (MI) and anemia did not significantly reduce the risk of recurrent MI or death at 30 days compared with a restrictive strategy that involved transfusions only when hemoglobin levels fell below 7 or 8 g/dl, based on findings from the MINT trial presented Nov. 11 at AHA 2023. However, researchers noted that potential harms of a restrictive transfusion strategy cannot be excluded.

MINT randomly assigned 3,506 patients with MI and a hemoglobin level of less than 10 g per deciliter to either a restrictive transfusion strategy (hemoglobin cutoff for transfusion, 7 or 8 g per deciliter) or a liberal transfusion strategy (hemoglobin cutoff, <10 g per deciliter). Participants were from 144 hospitals in the U.S., Canada, France, Brazil, New Zealand and Australia, 45% were women and the average age was 72 years.

The primary endpoint was the composite of all-cause death and recurrent MI through 30 days following trial randomization. All told, a primary-outcome event occurred in 295 of 1,749 patients (16.9%) in the restrictive-strategy group and in 255 of 1,755 patients (14.5%) in the liberal-strategy group. Death occurred in 9.9% of the patients in the restrictive strategy group compared with 8.3% of the patients in the liberal strategy group, while MI occurred in 8.5% of those in the restrictive group and 7.2% of those in the liberal strategy group.

Secondary outcomes included the individual components of the primary outcome, and the composite of all-cause death, MI, unscheduled coronary revascularization due to recurrent heart symptoms, or cardiovascular-related hospital readmission within 30 days. Researchers noted the liberal transfusion strategy was consistently favored in point estimates for the primary outcome and for these secondary outcomes. Additionally, the frequency of heart failure, and other safety-outcome events was similar across both groups.

“The study results require a nuanced interpretation,” said Jeffrey L. Carson, MD, in presenting the findings, which were also published in the New England Journal of Medicine. “While the trial did not produce a statistically significant difference between the two transfusion strategies for the primary outcome, the results suggest the possibility of liberal transfusion benefits without undue risk.” Carson added that future research is needed to “further resolve the controversy around treatment decisions” in this patient population.