Reviwer: Dr. Alper Karakuş

Name of the Study :  Randomized Trial of Transfusion Strategies in Patients With Myocardial Infarction and Anemia- REALITY

Presented Congress: ACC 21

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Background: Observational studies of transfusion strategies in acute myocardial infarction (AMI) have yielded many confusing results. The CRIT and the MINT randomized pilot studies compared transfusion strategies in AMI patients in a limited number of study populations, and again conflicting results were presented.

Objective: The REALITY study aimed to evaluate the safety and efficacy of the restrictive indication red cell suspension transfusion strategy compared to liberal transfusion strategy in patients with AMI and anemia.

Method: 666 patients with AMI (less than 48 hours since last ischemic symptom, STEMI or NSTMI) and hemoglobin value (Hgb) ≤8 to ≤10 g/dl (but >7 g/dl)  were included to study. The patients were 1:1 randomized to restrictive transfusion strategy group (n = 324, for Hgb ≤8 g/dl, target Hgb 8-10 g/dl ) or liberal   (n = 342, for Hgb ≤10 g/dl, target Hgb >11 g/dl) transfusion strategy group.

Results: At the end of the mean follow-up period of 30 days, the primary outcome (MACE) including all-cause death, re-infarction, stroke and ischemia caused by emergency revascularization was 11% in the restrictive strategy group and 14% in the liberal strategy group. In the per protocol and ITT cohort, noninfeiority criteria were met but no superiority criteria were met (HR 0.77, 95% CI 0.50-1.18, p < 0.05 noninferiority, p = 0.22 superiority). Looking at the primary outcome at the end of the first year, the ratio in the groups was 32.4% versus 28.1%, respectively, and noninferiority criteria were not met (HR 1.16, 95% CI 0.88-1.53). Analyzing the 1-year follow-up data, it was seen that the MACE curves crossed at 5 months in both strategy groups. Secondary outcome measures including bacterial infection (0% versus 1.5%; p=0.03) and acute respiratory distress syndrome (0.3% versus 2.2%; p=0.03) observed at a lower rate in the restrictive strategy group.

Conclusion: After 30 days of follow-up, the resctrictive transfusion strategy was shown to be non-inferior to the liberal transfusion strategy and was associated with more efficient cost-effectiveness. At the end of 1-year follow-up, it could not be shown to be non-inferior and was associated with a higher frequency of side effects.

Interpretation: The one-year data of the study unfortunately shows that there is still no clear transfusion strategy in AMI patients. However, considering that the REALITY study is the largest randomized study ever done on this subject, ongoing and new randomized studies will clear up the confusion.