Dr. Jeffrey L., Distinguished Professor of Medicine at Rutgers Robert Wood Johnson Medical School. An international clinical trial led by Carson found that generous blood transfusions given to patients who have had a heart attack and anemia can reduce the risk of a recurrence and improve survival rates. The results of the Myocardium Infarction and Transfusion (MINT) trial were published today New England Journal of Medicine. Maria Mori Brooks, professor of epidemiology and biostatistics at the University of Pittsburgh School of Public Health, is co-first author of the study.
Transfusion threshold trials are important in helping clinicians inform decisions that provide the most benefit to their patients. The aim of the MINT trial was to establish evidence that could be used to determine transfusion values for patients who have had a heart attack, improve their survival and reduce the risk of additional heart attacks.”
Jeffrey L. Carson, Rutgers Robert Wood Johnson Medical School Distinguished Professor of Medicine
The MINT trial evaluated two transfer strategies in more than 3,500 enrolled participants at 144 hospitals in six countries. Half of the study participants were given more blood to keep their blood counts above 10 grams per deciliter (g/dL), which was considered a liberal transfusion strategy. Half do not receive blood unless their blood count is less than eight g/dL, which is a barrier transfusion strategy. All patients in the study had a heart attack and were anemic, meaning they had a hemoglobin blood count of less than 10 g/dL. A normal blood count is 12 to 13 g/dL.
“The results of the MINT trial indicate that a liberal transfusion strategy can improve outcomes in anemic patients with heart attacks without causing undue harm,” Carson said.
Results of a multicenter randomized clinical trial funded by the National Institutes of Health’s National Heart, Lung, and Blood Institute (NHLBI) were presented at the Late-Breaking Scientific Session of the 2023 American Heart Association Annual Conference.
A large percentage of patients had previous heart attacks, heart failure, diabetes or kidney disease. The average age of the participants was 72, with 45 percent being women.
Although the transfusion strategy was randomly assigned, health professionals caring for hospitalized patients had clinical discretion to adhere to the study to ensure quality of care for their patients.
The researchers compared the frequency of the main outcome of death or recurrent heart attack 30 days after enrollment in the trial. Although not statistically significant, the study found that mortality or the frequency of recurrent heart attacks was 2.4 percent lower when a liberal regimen was used.
Brooks, the center’s principal investigator coordinating data from the MINT trial with 3,500 patients, said MINT provides the best data available to answer an important question that patients face every day.
“The test results indicate that the liberal strategy may be better, but they also suggest that the two approaches may be similar. These results challenge us to dig deeper,” Brooks said. “Do some patients benefit more than others? And why? Answering these questions will be our next step.”
For nearly two decades, Carson has studied the effects of red blood cell transfusion strategies toward providing optimal treatment for patients. His work helped establish transfusion guidelines in 2012 that physicians use to inform patient care, updates to which were announced last month. Journal of the American Medical Association Emphasis on an individualized approach in adults and children that accounts for comorbid conditions.
Carson and the study team emphasize that more clinical trials, meta-analyses of studies and additional analyzes of MINT trial data are important to ensure doctors are informed with the best evidence when considering when to transfuse patients with heart attack and anemia.
Carson, J. L., etc (2023) Restrictive or Liberal Transfusion Strategies in Myocardial Infarction and Anemia. New England Journal of Medicine. doi.org/10.1056/NEJMoa2307983.