Clinical question: What should be the transfusion target for patients hospitalized for myocardial infarction (MI) with anemia?
Background: Data on the optimal transfusion target for patients with MI and concurrent anemia are less established than for patients without active ischemia. To date, there have been three randomized trials, involving a total of 820 patients, investigating this issue. The largest of these was a European study with 668 patients and a noninferiority design that found restrictive transfusion (<8 g/dL) to be noninferior to liberal transfusion (≤10 g/dL) for the composite endpoint of death, reinfarction, stroke, and emergency revascularization at 30 days.
Study design: Phase 3, open-label, randomized, controlled trial
Setting: 144 sites in the U.S., Canada, France, New Zealand, and Australia
Synopsis: A total of 3,506 patients with STEMI or NSTEMI (type 1 or 2) with Hgb <10 g/dL were randomized to a restrictive transfusion strategy (for Hgb <7 to 8 g/dL) or a liberal strategy (Hgb <10 g/dL). Comparing restrictive and liberal transfusion-strategy groups, the composite primary outcome of MI or all-cause death within 30 days occurred in 16.9% versus 14.5% of patients, respectively (Relative Risk, 1.15; P=0.07), while secondary outcomes of death occurred in 9.9% versus 8.3% of patients and recurrent MI in 8.5% versus 7.2% of patients. In subgroup analyses, type 1 MI patients had higher rates of death or MI with restrictive management, an effect not seen for type 2 MI patients. The liberal strategy group had more protocol discontinuations (13.7% versus 2.6%), but only a small, nonsignificant increase in the incidence of heart failure (6.3% versus 5.8%) and other safety outcomes. Limitations include a lack of blinding, and that only the outcome of recurrent MI was centrally adjudicated. There was also heterogeneity in the MI population enrolled, with a majority (55.8%) with demand ischemia.
Bottom line: In the largest study on transfusion strategies in patients with MI and anemia, no significant difference in rates of recurrent MI or death was found between the restrictive (<7 to 8 g/dL) and liberal (≤10 g/dL) strategy groups, though slightly less favorable outcomes using the restrictive strategy was observed.
Citation: Carson JL, Brooks MM, et al. Restrictive or liberal transfusion strategy in myocardial infarction and anemia. N Engl J Med. 2023;389(26):2446-56.
Dr. Hui
Dr. Hui is a hospitalist in the division of hospital medicine at the Mount Sinai Health System and assistant professor of medicine at the Icahn School of Medicine at Mount Sinai in New York.