Restricting blood transfusion in anaemic heart attack patients to those with very low haemoglobin levels saves blood with no negative impact on clinical outcomes, a European study has shown.
The REALITY trial compared a restrictive vs liberal transfusion policy in 668 patients during hospital admission with acute MI and anaemia (haemoglobin 100 g/L or below, but above 70 g/L).
In the restrictive strategy, transfusion was withheld unless haemoglobin dropped to 80 g/L. In the liberal strategy, transfusion was given as soon as haemoglobin was 100 g/L or below.
Results presented at the European Society of Cardiology virtual meeting (ESC 2020) showed that the restrictive transfusion strategy was non-inferior to the liberal strategy in the primary endpoint of preventing major adverse cardiac events (MACE) at 30 days.
The primary clinical outcome occurred in 36 patients (11.0%) allocated to the restrictive strategy and 45 patients (14.0%) patients allocated to the liberal strategy (difference -3.0%; 95% confidence interval [CI] -8.4% to 2.4%).
The relative risk of 30-day MACE with the restrictive versus liberal strategy was 0.79.
Cost effectiveness analysis indicated that the restrictive strategy had an 84% probability of being cost-saving while improving clinical outcomes, i.e. “dominant” from a medico-economic standpoint.
Regarding safety, compared to patients receiving the liberal strategy, those allocated to the restrictive strategy were significantly less likely to develop an infection (restrictive 0.0% vs. liberal 1.5%; p=0.03) or acute lung injury (restrictive 0.3% vs. liberal 2.2%; p=0.03).
The study investigators said the findings should help resolve clinical uncertainty over the benefits of blood transfusion for anaemia, which affects 5–10% of patients with myocardial infarction and is an independent predictor of cardiac events and increased mortality.
Principal investigator Professor Philippe Gabriel Steg of Hospital Bichat, Paris, said: “Blood is a precious resource, and transfusion is costly, logistically cumbersome, and has side effects. The REALITY trial supports the use of a restrictive strategy for blood transfusion in myocardial infarction patients with anaemia.
“The restrictive strategy saves blood, is safe, and is at least as effective in preventing 30-day cardiac events compared to a liberal strategy, while saving money.”