The following is a summary of “Restrictive or Liberal Transfusion Strategy in Myocardial Infarction and Anemia,” published in the December 2023 issue of Hematology by Carson et al.

Researchers started a retrospective study to determine if maintaining higher hemoglobin levels than the current 7-8 g/dL threshold improves outcomes for patients with acute myocardial infarction.

They conducted a phase 3 interventional trial where patients with myocardial infarction and hemoglobin levels below 10 g/dL were randomly assigned to a restrictive transfusion strategy (transfusion cutoff at 7 or 8 g/dL) or a liberal transfusion strategy (cutoff <10 g/dL). The main outcome measured was a composite of myocardial infarction or death within 30 days.

The results showed that 3,504 patients were part of the primary analysis. In the restrictive-strategy group, the mean (±SD) number of transfused red-cell units was 0.7±1.6, while in the liberal-strategy group, it was 2.5±2.3. The mean hemoglobin level in the restrictive-strategy group was 1.3 to 1.6 g/dL lower than in the liberal-strategy group on days 1 to 3 after randomization. A primary-outcome event occurred in 16.9% of patients in the restrictive-strategy group and 14.5% in the liberal-strategy group (risk ratio with multiple imputation, 1.15; 95% CI, 0.99 to 1.34; P=0.07). Death occurred in 9.9% of patients with the restrictive strategy and 8.3% with the liberal strategy (RR, 1.19; 95% CI, 0.96 to 1.47); myocardial infarction occurred in 8.5% and 7.2% of patients, respectively (RR, 1.19; 95% CI, 0.94 to 1.49).

They concluded that liberal transfusions for anemic acute myocardial infarction patients didn’t cut 30-day risks, leaving optimal strategy and restrictive risks uncertain.

Source: nejm.org/doi/full/10.1056/NEJMoa2307983