A monthly roundup of key articles in other journals

Abstract

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. Ducrocq G, Gonzalez-Juanatey JR, Puymirat E, et al., JAMA 2021; 325(6): 552–60. In the REALITY trial, a restrictive red blood cell transfusion approach was found to be non-inferior to a liberal approach in patients with acute myocardial infarction. Anemia, common in patients with acute myocardial infarction (MI), has been associated with poorer clinical outcomes but the risks and benefits of liberal versus restrictive transfusion thresholds have not been wellstudied in this setting. The REALITY trial was an openlabel, non-inferiority, randomized trial evaluating transfusion strategies in patients with AMI across 26 centers in France and 9 centers in Spain. Adults with acute MI and hemoglobin (Hb) between 7 and 10 g/dl were randomly assigned 1:1 to either a restrictive (n = 342) or liberal (n = 324) transfusion threshold. Subjects in the restrictive arm were transfused for a Hb ≤8 g/dl, with a target range of 8–10 g/dl post-transfusion; the liberal group received transfusion for a Hb ≤10 g/dl, with a posttransfusion target of 11 g/dl. The primary outcome was a composite of major adverse cardiovascular events at 30 days (all-cause mortality, nonfatal stroke, nonfatal recurrent MI, or emergency revascularization prompted by ischemia). Noninferiority was defined as the upper bound of a one-sided 97.5% confidence interval (CI) for the relative risk of the primary outcome being less than 1.25. The restrictive transfusion strategy was non-inferior, but not superior, to the liberal approach. Major cardiovascular events occurred in 36 patients in the restrictive group and 45 in the liberal group, yielding a relative risk of 0.79 (one-sided 97.5% CI, 0.00–1.19). The individual components of the primary composite outcome were also comparable between groups: all-cause mortality was 5.6% in the restrictive group and 7.7% in the liberal group; recurrent MI was 2.1% and 3.1% respectively; emergency revascularization was 1.5% and 1.9%; and nonfatal stroke occurred in 0.6% in both groups. Transfusion was more common in the liberal group. The Hb at discharge was 11.1 (1.4) g/dl in the liberal group and 9.7 (1.0) g/dl in the restrictive group. Adverse events also occurred at comparable rates across groups: 11.7% of patients in the restrictive group and 11.1% in the liberal group. This study had a fairly small sample size. A larger trial in this setting (MINT, planned sample size = 3500) is underway.