Randomized Trial of Transfusion Strategies in Patients With Myocardial Infarction and Anemia - REALITY

The REALITY trial showed that a restrictive PRBC transfusion strategy (transfusion for Hgb ≤8 g/dl, goal Hgb 8-10 g/dl) is noninferior to a more liberal strategy (transfusion for Hgb ≤10 g/dl, goal Hgb >11 g/dl).

Description:

The goal of the trial was to assess the safety and efficacy of a restrictive versus liberal red blood cell (RBC) transfusion strategy among patients with acute myocardial infarction (AMI) and anemia. 

Study Design

Patients with AMI and hemoglobin (Hgb) ≤8 to ≤10 g/dl during admission were randomized in a 1:1 fashion to either a liberal (for Hgb ≤10 g/dl, goal Hgb >11 g/dl) (n = 342) or a restrictive (for Hgb ≤8 g/dl, target Hgb 8-10 g/dl) (n = 324) RBC transfusion strategy. The strategies should be maintained until discharge from hospital or for 30 days, whichever comes first.

  • Total number of enrollees: 666
  • Duration of follow-up: 30 days
  • Mean patient age: 77 years
  • Percentage female: 43%

Inclusion criteria:

  • MI (ST-segment elevation MI [STEMI] or NSTEMI)
    • Last ischemic symptoms <48 hours before admission
    • Troponin elevation
  • Anemia: Hb ≤10g/dl but >7 g/dl, at any time of index hospitalization for MI 

Exclusion criteria:

  • Cardiogenic shock
  • Post-percutaneous coronary intervention (PCI) or post-coronary artery bypass grafting (CABG) MI
  • Transfusion in the previous 30 days
  • Any known hematologic disease
  • Massive bleeding or compromising vital prognosis

Other salient features/characteristics:

  • Prior acute coronary syndrome (ACS): 36%
  • Prior PCI: 34%
  • Chronic anemia: 18%
  • On admission: NSTEMI: 70%, coronary angiography: 80%, PCI: 59%, CABG: 4%
  • Mean units of packed RBCs (PRBCs) per patient for restrictive vs. liberal transfusion strategy: 2.9 vs. 2.8
  • At least 1 unit PRBCs: 35.7% vs. 99.4% (p < 0.0001)

Principal Findings:

The primary outcome, all-cause death, reinfarction, stroke, and emergency revascularization prompted by ischemia for restrictive vs. liberal transfusion strategy, was 11.0% vs. 14.0% (hazard ratio 0.77, 95% confidence interval 0.50-1.18, p < 0.05 for noninferiority, p = 0.22 for superiority).

  • All-cause mortality: 5.6% vs. 7.7% (p > 0.05)
  • Recurrent MI: 2.1% vs. 3.1%
  • Emergency revascularization: 1.5% vs. 1.9%

Secondary outcomes for restrictive vs. liberal transfusion strategy:

  • Acute renal failure: 9.7% vs. 7.1% (p = 0.24)
  • Infection: 0% vs. 1.5% (p = 0.03)
  • Acute lung injury: 0.3% vs. 2.2% (p = 0.03)
  • Length of stay: 7.0 vs. 7.0 days (p = 0.84)
  • Total 30-day hospital costs: €11,051 vs. €12,572 (p = 0.1)

Interpretation:

The results of this trial indicate that a restrictive PRBC transfusion strategy (transfusion for Hgb ≤8 g/dl, goal 8-10 g/dl) is noninferior to a more liberal strategy (transfusion for Hgb ≤10 g/dl, goal Hgb >11 g/dl). In addition, infections and acute lung injury were higher with a more liberal strategy. Total blood utilization and costs were both lower with the restrictive strategy; this strategy was considered cost-dominant.

This is an important trial, and argues against the 10/30 rule that was once commonly practiced post-ACS. One minor point is that transfusions are frequently administered for Hgb ≤7 in clinical practice in the United States; the threshold studied in this trial was slightly higher (8 g/dl), possibly due to lack of equipoise for Hgb levels ≤7 g/dl. Similar results in favor of a restrictive strategy have been noted for post-cardiac and noncardiac surgery patients.

 

https://www.acc.org/latest-in-cardiology/clinical-trials/2020/08/29/13/09/reality