Using a more restrictive blood transfusion strategy is noninferior to a liberal transfusion strategy in treating anemic patients with acute myocardial infarction (MI) and is likely to save both money and blood, according to trial results presented Tuesday at the European Society of Cardiology (ESC) 2020 virtual congress.
Philippe Gabriel Steg, MD, of Hôpitaux Bichat, Paris, presented the results of the REALITY trial during a Hot Line session at ESC.
Anemia is common and is an independent predictor of cardiac events and increased mortality in MI patients. There is no consensus as to the best blood transfusion strategy for anemic MI patients. Randomized controlled trials have compared restrictive and liberal transfusion strategies in cardiac and non-cardiac surgery in patients with gastrointestinal bleeding, but these studies have excluded patients with acute MI.
The REALITY trial randomized 630 patients with acute MI and hemoglobin (Hb) between 7 and 10 g/dL at any time during admission to a liberal or restrictive red blood cell (RBC) transfusion strategy. The study was conducted at 35 hospitals in France and Spain.
Under the liberal strategy, a transfusion was triggered by Hb ≤10 g/dL and targeted raising Hb to >11 g/dL. Under the restrictive strategy, a transfusion was triggered by Hb ≤8 g/dL and targeted raising Hb to 8 to 10 g/dL.
The primary endpoints were: clinical, 30-day major adverse cardiac events (MACE, a composite of death; reinfarction; stroke; and emergency, ischemia-driven revascularization), and cost-effectiveness, 30-day incremental cost-effectiveness ratio.
Hb levels were similar between the two groups at admission and randomization. At discharge, patients who received the restrictive transfusion strategy (n=342) had a mean Hb of 9.7±1.0 g/dL, while those who received the liberal transfusion strategy (n=324) had a mean Hb of 11.1±1.4 g/dL (p<0.0001).
Fewer than half of restrictive-strategy patients received a transfusion (n=122, 35.7%), while most liberal-strategy patients were transfused (n=280, 86.7%; p<0.0001). As a result, restrictive-strategy patients received a total of 342 RBC units, which saved 414 units compared to the 756 received by the liberal-strategy patients. The mean number of units transfused per patient was similar between the groups (restrictive strategy, 2.9±3.7 g/dL vs. liberal strategy, 2.8±2.7 g/dL).
The per-protocol population for the primary clinical outcome showed that the restrictive strategy was noninferior to the liberal strategy; 11% of patients in the restrictive-strategy group experienced MACE as compared to 14% in the liberal-strategy group (difference: -3.0%; 95% confidence interval [CI, -8.4%, 2.4%]; relative risk, 0.79). The upper side of the 97.5% CI of the relative risk was 1.18, which was within the noninferiority margin of 1.25.
Steg said these results were also verified in the intention-to-treat population.
Safety events were similar between the groups except for infection and acute lung injury, both of which favored the restrictive strategy. There were no infections in the restrictive-strategy group and 5 in the liberal-strategy group (0.0% vs. 1.5%; difference: -1.5%; 95% CI [-3.2%, 0.1%]; p=0.03). The restrictive-strategy group had 1 acute lung injury, while the liberal-strategy group had 7 (0.3% vs. 2.2%; difference: -1.9%; 95% CI [-3.9%, 0.1%]; p=0.03).
A cost-effective analysis showed that the restrictive transfusion strategy had an 84% probability of being dominant, that is, both more effective and lower cost, as compared to the liberal strategy.
“The restrictive transfusion strategy is noninferior to a liberal strategy in preventing 30-day MACE, saves blood and is safe,” Steg said. “Cost-effectiveness analysis indicated that the restrictive strategy has a high probability of being cost-saving while being outcome-improving, i.e., dominant. These observations support the use of the restrictive strategy.”
The REALITY trial was sponsored by Assistance Publique – Hôpitaux de Paris and received funding from the French Ministry of Health and Spanish Ministry of Economy and Competitiveness.