Effect of a Restrictive vs Liberal Blood Transfusion Strategy on Major Cardiovascular Events Among Patients With Acute Myocardial Infarction and Anemia

Abstract

IMPORTANCEThe optimal transfusion strategy in patients with acute myocardial infarction and anemia is unclear.OBJECTIVE To determine whether a restrictive transfusion strategy would be clinically noninferior to a liberal strategy. DESIGN, SETTING, AND PARTICIPANTSOpen-label, noninferiority, randomized trial conducted in 35 hospitals in France and Spain including 668 patients with myocardial infarction and hemoglobin level between 7 and 10 g/dL. Enrollment could be considered at any time during the index admission for myocardial infarction. The first participant was enrolled in March 2016 and the last was enrolled in September 2019. The final 30-day follow-up was accrued in November 2019.INTERVENTIONS Patients were randomly assigned to undergo a restrictive (transfusion triggered by hemoglobin Յ8; n = 342) or a liberal (transfusion triggered by hemoglobin Յ10 g/dL; n = 324) transfusion strategy. MAIN OUTCOMES AND MEASURESThe primary clinical outcome was major adverse cardiovascular events (MACE; composite of all-cause death, stroke, recurrent myocardial infarction, or emergency revascularization prompted by ischemia) at 30 days. Noninferiority required that the upper bound of the 1-sided 97.5% CI for the relative risk of the primary outcome be less than 1.25. The secondary outcomes included the individual components of the primary outcome. RESULTS Among 668 patients who were randomized, 666 patients (median [interquartile range] age, 77 [69-84] years; 281 [42.2%] women) completed the 30-day follow-up, including 342 in the restrictive transfusion group (122 [35.7%] received transfusion; 342 total units of packed red blood cells transfused) and 324 in the liberal transfusion group (323 [99.7%] received transfusion; 758 total units transfused). At 30 days, MACE occurred in 36 patients (11.0% [95% CI, 7.5%-14.6%]) in the restrictive group and in 45 patients (14.0% [95% CI, 10.0%-17.9%]) in the liberal group (difference, −3.0% [95% CI, −8.4% to 2.4%]). The relative risk of the primary outcome was 0.79 (1-sided 97.5% CI, 0.00-1.19), meeting the prespecified noninferiority criterion. In the restrictive vs liberal group, all-cause death occurred in 5.6% vs 7.7% of patients, recurrent myocardial infarction occurred in 2.1% vs 3.1%, emergency revascularization prompted by ischemia occurred in 1.5% vs 1.9%, and nonfatal ischemic stroke occurred in 0.6% of patients in both groups.CONCLUSIONS AND RELEVANCE Among patients with acute myocardial infarction and anemia, a restrictive compared with a liberal transfusion strategy resulted in a noninferior rate of MACE after 30 days. However, the CI included what may be a clinically important harm.

Red cell transfusions: Is less always best?

“…The recently published Restrictive and Liberal Transfusion Strategies in Patients with Acute Myocardial Infraction (REALITY) trial in 668 patients with AMI and anemia showed non‐inferiority of a restrictive versus liberal strategy (Hb trigger <80g/L versus <100g/L) for the primary outcome of major adverse cardiac events. Although the primary outcome was numerically lower in the restrictive group (11% versus 14%), the statistical signifiance for superiority was not met 26 . It is hoped that a larger trial such as MINT, powered for clinical superiority, will provide further answers.…”

“…Although the primary outcome was numerically lower in the restrictive group (11% versus 14%), the statistical signifiance for superiority was not met. 26 It is hoped that a larger trial such as MINT, powered for clinical superiority, will provide further answers.…”

Reducing unnecessary red blood cell transfusion in hospitalised patients

“…Uncertainty remains around the optimal transfusion threshold in patients with acute coronary syndrome or chronic cardiovascular disease 14. Most studies in patients with acute coronary syndrome support restrictive transfusion with a haemoglobin threshold less than 80 g/L 1516. Further, no firm criteria exist for RBC transfusion during pregnancy, and the decision to provide blood transfusion should be made on clinical and haematological grounds 17…”

Early detection of anaemia in primary care with haemoglobinometry: ANHEMOG clinical trial protocol

“…6 Departament de Geriatria, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain. 7 Servei d' Atenció Primària Barcelonés Nord i Maresme, Gerència Territorial Metropolitana Nord, Institut Català de la Salut, Barcelona, Spain. 8 Centre d' Atenció Primària La Riera (Mataró 1), Institut Català de la Salut, Barcelona, Spain.…”

“…In asymptomatic patients without cardiovascular risks, transfusion is rarely needed until Hb drops below 7-8 g/dl or haematocrit falls between 21 and 24%, although there are some clinical circumstances in which is not recommended to let Hb drop that low for an extended period, or the optimal transfusion strategy is unclear. For example, in patients with coronary artery disease, it has been found that a restrictive transfusion strategy (in most cases, with the limit at 9 mg/dl) is linked to a higher risk of experiencing another cardiac ischemic event, while a personalized, liberal transfusion strategy lowers that same risk [7][8][9][10][11], however, the observed results of a recent clinical trial suggests that there may be merit to a restrictive strategy [7].…”