Effect Of A Restrictive Vs Liberal Blood Transfusion Strategy On Major Cardiovascular Events Among Patients With Acute Myocardial Infarction And Anemia The Reality Randomized Clinical Trial

This noninferiority trial compares the effects of a restrictive (hemoglobin <= 8 g/dL) vs liberal (hemoglobin <= 10 g/dL) transfusion strategy on 30-day cardiovascular events among adults with acute myocardial infarction (AMI) and anemia (hemoglobin 7-10 g/dL).Question Is a restrictive strategy of blood transfusion noninferior to a liberal strategy among patients with acute myocardial infarction and anemia? Findings In this randomized clinical trial that included 668 patients with acute myocardial infarction and hemoglobin level between 7 and 10 g/dL who were treated with a restrictive transfusion strategy (triggered by hemoglobin <= 8 g/dL) vs a liberal strategy (triggered by hemoglobin <= 10 g/dL), the composite outcome (all-cause death, stroke, recurrent myocardial infarction, or emergency revascularization) at 30 days occurred in 11% vs 14% of patients, a difference that met the noninferiority criterion of relative risk less than 1.25. Meaning A restrictive transfusion strategy compared with a liberal strategy resulted in a noninferior rate of major cardiovascular events among patients with acute myocardial infarction and anemia, but the CI included what may be a clinically important harm.Importance The optimal transfusion strategy in patients with acute myocardial infarction and anemia is unclear. Objective To determine whether a restrictive transfusion strategy would be clinically noninferior to a liberal strategy. Design, Setting, and Participants Open-label, noninferiority, randomized trial conducted in 35 hospitals in France and Spain including 668 patients with myocardial infarction and hemoglobin level between 7 and 10 g/dL. Enrollment could be considered at any time during the index admission for myocardial infarction. The first participant was enrolled in March 2016 and the last was enrolled in September 2019. The final 30-day follow-up was accrued in November 2019. Interventions Patients were randomly assigned to undergo a restrictive (transfusion triggered by hemoglobin <= 8; n = 342) or a liberal (transfusion triggered by hemoglobin <= 10 g/dL; n = 324) transfusion strategy. Main Outcomes and Measures The primary clinical outcome was major adverse cardiovascular events (MACE; composite of all-cause death, stroke, recurrent myocardial infarction, or emergency revascularization prompted by ischemia) at 30 days. Noninferiority required that the upper bound of the 1-sided 97.5% CI for the relative risk of the primary outcome be less than 1.25. The secondary outcomes included the individual components of the primary outcome. Results Among 668 patients who were randomized, 666 patients (median [interquartile range] age, 77 [69-84] years; 281 [42.2%] women) completed the 30-day follow-up, including 342 in the restrictive transfusion group (122 [35.7%] received transfusion; 342 total units of packed red blood cells transfused) and 324 in the liberal transfusion group (323 [99.7%] received transfusion; 758 total units transfused). At 30 days, MACE occurred in 36 patients (11.0% [95% CI, 7.5%-14.6%]) in the restrictive group and in 45 patients (14.0% [95% CI, 10.0%-17.9%]) in the liberal group (difference, -3.0% [95% CI, -8.4% to 2.4%]). The relative risk of the primary outcome was 0.79 (1-sided 97.5% CI, 0.00-1.19), meeting the prespecified noninferiority criterion. In the restrictive vs liberal group, all-cause death occurred in 5.6% vs 7.7% of patients, recurrent myocardial infarction occurred in 2.1% vs 3.1%, emergency revascularization prompted by ischemia occurred in 1.5% vs 1.9%, and nonfatal ischemic stroke occurred in 0.6% of patients in both groups. Conclusions and Relevance Among patients with acute myocardial infarction and anemia, a restrictive compared with a liberal transfusion strategy resulted in a noninferior rate of MACE after 30 days. However, the CI included what may be a clinically important harm.