medwireNews: In patients with acute myocardial infarction (MI) and anemia, there was no significant difference between liberal and restrictive transfusion strategies for the composite outcome of death and recurrent MI at 30 days, reveals the MINT trial published in The New England Journal of Medicine.
However, Jeffrey Carson (Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA) and team report that, while there was no significant difference, “the liberal transfusion strategy was consistently favored in point estimates for the primary outcome.”
The MINT trial included 3504 patients (45.5% women) with ST-segment or non–ST-segment elevation MI and anemia, defined as a hemoglobin level below 10 g/dL. They were enrolled from 144 sites in the USA, Canada, France, Brazil, New Zealand, and Australia, and had a mean age of 72.1 years.
The participants were randomly assigned to either a liberal-strategy group, who received a transfusion when hemoglobin levels dropped below 10 g/dL (n=1755) or a restrictive-strategy group where a transfusion was permitted when hemoglobin levels dropped below 8 g/dL and strongly recommended when they dropped below 7 g/dL (n=1749).
Patients in the liberal-strategy group received 3.5 times the total number of red blood cell transfusions, at an average 2.5 units, compared with 0.7 units received by the restrictive-strategy group. The mean hemoglobin level was 1.3 g/dL higher on day 1 and 1.6 g/dL higher on day 3 in the liberal-strategy than the restrictive-strategy group.
The rate of death from any cause or recurrent MI at 30 days was slightly lower in the liberal-strategy group than the restrictive-strategy group, at 14.5% versus 16.9%, and a nonsignificant estimated risk ratio of 1.15.
There was also no significant difference in the risk for death, which occurred in 8.3% of patients in the liberal-strategy group compared with 9.9% of those in the restrictive-strategy group, nor MI event, which affected a respective 7.2% and 8.5%. The investigators note that cardiac death occurred less frequently in the liberal-strategy than the restrictive-strategy group, with corresponding rates of 5.5% and 3.2%, but not significantly so.
The composite secondary endpoint of death, myocardial infarction, ischemia-driven unscheduled coronary revascularization, or readmission to the hospital for an ischemic cardiac condition within 30 days occurred in 17.4% of patients in the liberal-strategy group versus 19.6% of the patients, again with no significant difference in the risk, at a ratio of 1.13.
“Whether to transfuse is an everyday decision faced by clinicians caring for patients with acute myocardial infarction,” the researchers comment.
They conclude that the “[t]rial end points suggest some benefit of a liberal strategy over a restrictive strategy, but additional studies would be needed to confirm that conclusion.”
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