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

May 16, 2021
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Author/Summarized by Author:
Dharam J. Kumbhani, MD, SM, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Date Presented:
05/16/2021
Date Updated:
05/16/2021
Original Posted Date:
09/01/2020
References

Contribution To Literature:

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)

1-year outcomes:

  • Primary outcome for restrictive vs. liberal transfusion strategy: 32.4% vs. 28.1%; HR 1.16, 95% CI 0.88-1.53 (p for noninferiority not met)
  • <5 months: HR 1.0, 95% CI 0.72-1.38
  • ≥5 months: HR 1.71, 95% CI 1.00-2.94
  • For patients alive at 30 days, HR 1.44, 95% CI 1.01-2.03
  • All-cause mortality: 23.1% vs. 20.4%
  • Recurrent MI: 9.6% vs. 6.5%

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) at 30 days. 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. On 1-year follow-up, the curves appear to cross around 5 months, such that a restrictive strategy is no longer noninferior to a more liberal strategy, and may even be associated with higher adverse event rates.

This is an important trial, and argues against the 10/30 rule that was once commonly practiced post-ACS. One-year data suggest that the jury may still be out on this topic though. 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. Data from other ongoing trials are awaited.

References:

Presented by Dr. Jose P. Gonzalez-Juanatey at the American College of Cardiology Virtual Annual Scientific Session (ACC 2021), May 16, 2021.

Presented by Dr. Philippe Gabriel Steg at the European Society of Cardiology Virtual Congress, September 1, 2020.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Stable Ischemic Heart Disease, Vascular Medicine, Aortic Surgery, Cardiac Surgery and SIHD, Interventions and ACS, Interventions and Imaging, Interventions and Vascular Medicine, Angiography, Nuclear Imaging, Chronic Angina

Keywords: ACC Annual Scientific Session, ACC21, ESC Congress, ESC20, Acute Coronary Syndrome, Acute Lung Injury, Anemia, Blood Cells, Blood Transfusion, Coronary Angiography, Erythrocyte Transfusion, Hemoglobins, Hospital Costs, Length of Stay, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, ST Elevation Myocardial Infarction, Patient Discharge, Percutaneous Coronary Intervention, Stroke, Troponin


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