Restrictive transfusion thresholds have been found to be beneficial for most patients. Anemia, however, is associated with poor outcomes in patients with acute myocardial infarction (AMI) and a more liberal transfusion threshold and higher hemoglobin levels might increase oxygen delivery and improve outcomes. Observational studies and small randomized clinical trials have yielded conflicting results for transfusion thresholds in these patients. In order to evaluate whether a restrictive transfusion strategy is noninferior to a liberal strategy in anemic patients with AMI, researchers in France and Spain randomized and followed 666 patients (median age, 77 years; 42.2% women) with anemia and AMI for 30 days. Overall, 35.7% of the patients (122/342) in the restrictive transfusion group (transfusion threshold < 8 g/dL hemoglobin) received at least one red blood cell transfusion compared to 99.7% (323/324) in the liberal group (transfusion threshold < 10 g/dL hemoglobin). Further, 30-day follow-up data found 36 patients (11.0%) in the restrictive group and 45 patients (14.0%) in the liberal group had a major adverse cardiovascular event (including death, stroke, recurrent myocardial infarction, or emergency revascularization) meeting the noninferiority criterion. Of note, the noninferiority margin of 1.25 in this study may have been too large, thus potentially masking a clinically important harm for patients in the liberal group. Additional larger randomized clinical trials comparing restrictive and liberal transfusion thresholds in patients with myocardial infarctions are needed, as this trial was also not powered to determine superiority.
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