Early-Stage Transfusions Linked to Improved Health Post-Heart Attack

A comprehensive study, supported by the National Institutes of Health, has yielded insights into transfusion approaches for adults experiencing anaemia post-heart attack. The research, conducted over five years as part of the Myocardial Ischemia and Transfusion (MINT) trial, involved more than 3,500 participants across 144 sites in six countries. 

The trial aimed to determine the impact of two transfusion approaches – liberal and restrictive – on the likelihood of subsequent heart attacks or mortality within 30 days. Individuals were randomized to receive red blood cell transfusions either during moderate anaemia (liberal approach) or when anaemia reached a more severe stage (restrictive approach).

Contrary to expectations, the study found that the choice of transfusion approach did not significantly influence the occurrence of subsequent heart attacks or deaths within the specified timeframe. 

However, the researchers observed a nuanced trend: individuals who received blood transfusions at an earlier stage of anaemia appeared to experience slightly better health outcomes. This finding prompts a revaluation of transfusion decision-making, advocating for a flexible and individualized approach rather than a one-size-fits-all strategy. 

Principal investigator Dr. Jeffrey L. Carson, a distinguished professor of medicine at Rutgers Robert Wood Johnson Medical School, noted, “We think these results suggest that a liberal transfusion strategy may be most prudent for some patients without introducing excess risks of harm.” The emphasis on individual patient needs and potential benefits underscores the importance of a nuanced, case-by-case assessment in clinical practice. 

Published in the New England Journal of Medicine and presented at the American Heart Association’s 2023 Scientific Sessions, the study challenges existing paradigms in the treatment of anaemia following a heart attack. An estimated 11–38% of heart attack survivors develop anaemia, a condition marked by a dangerous drop in haemoglobin levels. Until this study, there has been a lack of concrete evidence guiding clinicians on when to initiate blood transfusions in such cases. 

Current practice involves initiating transfusions if a person’s haemoglobin falls below 10 g/dL, which can improve oxygen delivery to the heart and reduce complications. However, replenishing red blood cells too early can pose risks such as fluid retention, inflammation, and adverse outcomes like heart failure. The restrictive approach, waiting until haemoglobin levels fall below 7–8 g/dL, has been an alternative strategy to minimize these risks. 

The trial’s results indicate that neither transfusion approach led to statistically significant differences in heart attacks or deaths, the primary outcomes assessed. Notably, neither approach introduced unnecessary risks for harm. The study’s findings underscore the complexity of the decision-making process in transfusion strategies, emphasizing the need for clinicians to carefully balance the potential benefits and risks for each patient. 

Additional outcomes, including unplanned heart surgery and cardiac rehospitalization, were considered in the analysis. While no substantial disparities were found in heart attacks or deaths between the two approaches, the liberal strategy demonstrated potential benefits in terms of a lower percentage of deaths and major adverse events during the 30-day follow-up period. 

The MINT trial challenges conventional transfusion practices for post-heart attack anaemia, suggesting that a tailored, liberal approach may offer advantages for certain patients without introducing undue risks. These findings encourage a revaluation of transfusion protocols and highlight the importance of personalized decision-making in managing anaemia following a heart attack. 

News Reference  

National Institute of Health (NIH), “Different transfusion approaches for helping heart attack patients who develop anaemia recover led to similar 30-day outcomes” Different transfusion approaches for helping heart attack patients who develop anemia recover led to similar 30-day outcomes | National Institutes of Health (NIH).