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Transfusing More Blood to Heart Attack Patients With Anemia Reduces Risk of Death

Key Takeaways

  • Restrictive transfusion strategy in anemic heart attack patients is linked to higher 6-month mortality compared to a liberal approach.
  • The MINT trial analyzed data from 4311 patients across 4 clinical trials, focusing on transfusion strategies.
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Data from a follow-up at 6 months show a reduced risk of all-cause mortality in heart attack patients with anemia who receive a liberal transfusion strategy compared with a restrictive one.

Data from an individual patient-level data meta-analysis indicate that a restrictive blood transfusion strategy for heart attack patients with anemia was associated with increased all-cause mortality at 6 months when compared to a liberal transfusion approach, affirming previous results indicating that a high mortality rate or recurrent heart attacks can be more frequent in anemic patients who receive less blood.1,2

Heart attack

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There has been insufficient data available to provide accurate clinical guidelines for the use of red cell transfusion in patients with acute myocardial infarction (MI) and anemia. In 2023, the results of the Myocardial Infarction and Transfusion (MINT) trial were published, led by Jeffrey L Carson, MD, and featured patients who had suffered a previous heart attack or had comorbidities such as heart failure, kidney disease, or diabetes. Carlson sought to analyze combined data from similar trials to garner more precise estimates of the effects of varying transfusion regimens.1,2

Carson et al searched major databases to find eligible trials, which were defined as those that randomly assigned patients with MI and anemia to either a restrictive red cell transfusion strategy—defined as a transfusion threshold of 7-8 g/dl—or a liberal transfusion strategy, which was a transfusion threshold of 10 g/dl. Individual patient data from each trial was used; the primary outcome of the analysis was a composite of 30-day mortality or MI.1

In total, data for 4311 patients from 4 clinical trials evaluating blood transfusions in patients with heart attacks were gathered. The trials featured patients who had heart attack and were anemic; half of the patients received a restrictive transfusion strategy, while the other half had a liberal transfusion strategy. The frequency of death at 30 days, or recurrent heart attacks and death at 6 months, were analyzed.1,2

The study authors found that the primary outcome occurred in 334 patients (15.4%) in the restrictive strategy cohort and 296 patients (13.8%) in the liberal strategy cohort (relative risk [RR]: 1.13; 95% CI, 0.97-1.30). At 30 days, death occurred in 9.3% of patients in the restrictive strategy and in 8.1% of patients receiving a liberal strategy (RR: 1.15; 95% CI, 0.95-1.39). Cardiac death at 30 days was observed in 5.5% of patients receiving a restrictive transfusion strategy and 3.7% of patients with a liberal transfusion strategy (RR: 1.47; 95% Ci, 1.11-1.94).1

Notably, the rates of heart failure were similar across both transfusion strategies (RR: 0.89; 95% CI, 0.70-1.13), meaning the primary trial outcome was not met because there was not a definitive difference in MI or death at 30 days. However, at 6 months, all-cause mortality was higher in patients receiving the restrictive strategy compared with those receiving the liberal transfusion strategy (20.5% vs 19.1%; HR: 1.08; 95% CI, 1.05-1.11), suggesting that using less transfusions in this patient population was associated with increased risk of death at 6 months.1,2

‘The results of this analysis show that giving more blood to anemic patients with heart attacks can save lives at 6 months,” Carson said in a news release.2

Given the seriousness of heart attack and other cardiovascular conditions in patients with anemia, pharmacists and treatment providers must be aware of a patient’s medical history and ensure it accurately reflects any past conditions, including past heart attacks. Knowing this information can allow for tailored transfusion strategies for patients with anemia.

REFERENCES
1. Carson JL, Fergusson DA, Noveck H, et al. Restrictive versus liberal transfusion in myocardial infarction – a patient-level meta-analysis. NEJM Evidence. 2024. Accessed January 7, 2025. doi:10.1056/EVIDoa2400223
2. Study finds transfusing more blood reduces risk of death at six months in heart-attack patients with anemia. News Release. Rutgers University. December 23, 2024. Accessed January 7, 2025. https://www.eurekalert.org/news-releases/1069099
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