Managing Transfusion in Myocardial Infarction

Research Highlights:

A multinational trial compared outcomes examined in patients with anemia and heart attacks who received blood transfusions when their hemoglobin concentration levels were 8 g/dL or 10 g/dL.
Although the results did not reach statistical significance, the findings indicate that blood transfusions for anemic patients hospitalized with a heart attack to maintain hemoglobin concentration above 10 g/dL can improve the patient’s health.
As the largest trial evaluating transfusion thresholds in people after a heart attack, the results may help guide decisions for doctors caring for patients with anemia and a heart attack.

Background

The strategy of administering a transfusion only when the hemoglobin level falls below 7 or 8 g per deciliter has been widely adopted . However, patients with acute myocardial infarction may benefit from a higher hemoglobin level.

Methods

In this phase 3 interventional trial, we randomly assigned patients with myocardial infarction and a hemoglobin level less than 10 g per deciliter to a restrictive transfusion strategy (hemoglobin limit for transfusion, 7 or 8 g per deciliter) or a of liberal transfusion (hemoglobin limit, <10 g per deciliter).

The primary outcome was a composite of myocardial infarction or death at 30 days.

Results

A total of 3,504 patients were included in the primary analysis. The mean (±SD) number of RBC units transfused was 0.7 ± 1.6 in the restrictive strategy group and 2.5 ± 2.3 in the liberal strategy group.

The mean hemoglobin level was 1.3 to 1.6 g per deciliter lower in the restrictive strategy group than in the liberal strategy group on days 1 to 3 after randomization.

A primary outcome event occurred in 295 of 1749 patients (16.9%) in the restrictive strategy group and in 255 of 1755 patients (14.5%) in the liberal strategy group (hazard ratio modeled with multiple imputation for incomplete follow-up, 1.15; 95% confidence interval [CI], 0.99 to 1.34; P = 0.07).

Death occurred in 9.9% of patients with the restrictive strategy and 8.3% of patients with the liberal strategy (relative risk, 1.19; 95% CI, 0.96 to 1.47). ); myocardial infarction occurred in 8.5% and 7.2% of patients, respectively (hazard ratio, 1.19; 95% CI, 0.94 to 1.49).

Conclusions

In patients with acute myocardial infarction and anemia, a liberal transfusion strategy did not significantly reduce the risk of recurrent myocardial infarction or death at 30 days. However, potential harms from a restrictive transfusion strategy cannot be excluded.

(Funded by the National Heart, Lung, and Blood Institute and others; MINT ClinicalTrials.gov number, NCT02981407. opens in new tab.)

Managing Transfusion in Myocardial Infarction

Evaluation of restrictive versus liberal transfusion strategies in myocardial infarction and anemia.