Research Highlights:
Embargoed until 10:10 a.m. ET, Saturday, Nov. 11, 2023
PHILADELPHIA, Nov. 11, 2023 — While the indications for red blood cell transfusion are controversial for people hospitalized with a heart attack , a randomized controlled trial of more than 3,500 people suggests there may be benefits to an expanded transfusion approach, according to late-breaking science presented today at the American Heart Association’s Scientific Sessions 2023 . The meeting, Nov. 11-13, in Philadelphia, is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in cardiovascular science. The full manuscript is also simultaneously published today in The New England Journal of Medicine .
Previous studies on transfusion strategies for people hospitalized with heart attack have yielded conflicting results. Doctors thought giving more blood transfusions would increase the amount of oxygen for the heart and improve outcomes. However, giving more blood transfusions may increase the risk of fluid overload and rare infections. This uncertainty in when to transfuse heart attack patients led to this trial called Myocardial Ischemia and Transfusion (MINT).
“Low red blood count or anemia is common among people hospitalized with heart attack,” said study author Jeffrey L. Carson, M.D., who is provost and distinguished professor of medicine at Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey, and holds the Richard C. Reynolds chair in general internal medicine. “We believe our results suggest a more liberal transfusion approach may be beneficial for these patients without significant risk.”
In the MINT trial, anemia was defined as a hemoglobin concentration of less than 10 g/dL. Participants were randomly allocated to a restrictive or a liberal transfusion strategy. In the liberal transfusion strategy, red blood cells were transfused to maintain the hemoglobin at or above 10 g/dL through hospital discharge or 30 days. In the restrictive transfusion strategy, transfusion was permitted only when the hemoglobin concentration was less than 8 g/dL and strongly recommended when the hemoglobin concentration was less than 7 g/dL or for cardiac symptoms not controlled with medications.
The analysis found:
“The study results require a nuanced interpretation. While the trial did not produce a statistically significant difference between the two transfusion strategies for the primary outcome, the results suggest the possibility of liberal transfusion benefits without undue risk,” Carson said. “The MINT results suggest a liberal transfusion strategy may be the most prudent approach for patients with heart attack and anemia.”
Trial background and details:
MINT results should be interpreted with caution because the analyses were not adjusted for multiple statistical tests, Carson said. Other limitations include that treating clinicians knew which strategy participants were assigned to, and not all participants were discharged with hemoglobin concentration levels greater than 10 g/dL in the liberal transfusion group. This was frequently due to clinical discretion, such as concerns about fluid overload and timing of hospital discharge. In addition, recurrent myocardial infarction was the only outcome confirmed by an independent committee, and hence, the cause of death was classified by the research team at the study hospital.
“Future research is needed to further resolve the controversy around transfusion decisions for people with anemia and heart attack,” Carson noted.
Co-authors, disclosures and funding sources are listed in the abstract.
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