More Boxcars? Transfusion Trigger for STEMI and NSTEMI
December 11, 2023
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Written by Millie Cossé
Liberalizing the transfusion threshold to 10 g/dL (compared to 7-8 g/dL) for patients with myocardial infarction did not improve composite outcomes of myocardial infarction or death at 30 days.
Every drop (of blood) counts…. or does it?
This is a phase 3 randomized control trial in which 3,504 patients with myocardial infarction and anemia were randomized to either restrictive or liberal blood transfusion groups. Patients in the restrictive transfusion group would receive packed red blood cell transfusion for hemoglobin 7-8g/dL, while those in the liberal transfusion group would receive blood transfusion for hemoglobin values <10g/dL. Adult patients with STEMI or NSTEMI were included in the analysis to improve generalizability.
The primary outcome was a composite of risk of death or further myocardial infarction at 30 days. A primary-outcome event occurred in 16.9% of patients in the restrictive group and 14.5% in the liberal group (risk ratio 1.15; 95%CI 0.99 to 1.34). Cardiac death occurred in 5.5% of patients in the restrictive transfusion group compared to 3.2% in the liberal transfusion group (risk ratio 1.74; 95%CI 1.26 to 2.40). While neither result is statistically significant, authors note that the safety profile of both transfusion strategies were similar, and that trial end points suggest some benefit of a liberal transfusion strategy.
How will this change my practice?
I don’t see a way to apply these results to my clinical practice. In my mind, there is a huge difference between a type II NSTEMI due to transient tachyarrhythmia and a true occlusion myocardial infarction in terms of why a blood transfusion might be helpful. Also, a lot of the results approach statistical significance, and I can’t help but wonder if there is a specific subgroup that would benefit from a liberalized transfusion threshold. For now, I’ll just keep it simple and transfuse symptomatic anemia on a case by case basis.
Another Spoonful: Transfusion Trigger – New AABB Guidelines for Adults and Children
Restrictive or Liberal Transfusion Strategy in Myocardial Infarction and Anemia. N Engl J Med. 2023 Nov 11. doi: 10.1056/NEJMoa2307983. Epub ahead of print.