Restrictive Transfusions for Acute MI, Anemia Linked to Higher Risk for MACE

Jonathan Alicea

The 1-year follow-up of the REALITY trial presented at ACC undermines previously reported 30-day findings showing noninferiority to liberal transfusions.

An updated analysis of the Restrictive and Liberal Transfusion Strategies in Patients with Acute Myocardial Infarction (REALITY) study indicated that—at 1 year—a restrictive blood transfusion was no longer clinically noninferior to a liberal transfusion among patients with acute myocardial infarction and anemia.

Previously, the investigators of the joint Spanish/French trial reported 30-day outcomes, originally noting the noninferiority of both strategies.

Attending ACC 2021? Share your thoughts on the meeting, and the state of cardiology, with our 2-minute survey!

However, at 1-year follow-up, a more restriction transfusion strategy, trigged by hemoglobin ≤8 g/dL, was associated with higher outcomes of major adverse cardiovascular events (MACE), when compared with a liberal transfusion strategy, triggered by hemoglobin ≤10 g/dL.

These findings were presented at the American College of Cardiology (ACC) Annual Scientific Session by José González-Juanatey, MD, University Hospital, Santiago de Compostela, Spain.

Background to the REALITY Trial

The investigators enrolled 668 patients with myocardial infarction and hemoglobin levels >7 g/dL - ≤10 g/dL. The intention-to-treat population included 666 patients.

Patients were then randomized 1:1 to either a restrictive or a liberal transfusion strategy. The primary outcome sought by the team were events of all-cause death, stroke, recurrent myocardial infarction, or emergency revascularization.

The investigators monitored MACE during patient hospital stays

Original 30-day data showed that the primary outcome occurred in 11% in the restrictive group and 14% in the liberal group (RR, 0.79; 97.5% CI, 0-1.19). Additionally, it met the prespecified noninferiority margin (1.25).

At the time, the investigators reported that all-cause death occurred in 5.6% and 7.7% of patients in the restrictive and liberal groups, respectively. Recurrent myocardial infarction occurred in 2.1% in the restrictive group and 3.1% in the liberal group.

1-Year Follow-up

“At 1 year, the primary outcome occurred in 111/342 patients and in 92/324 in the restrictive group and the liberal group respectively (HR, 1.16; 95% CI, 0.88-1.53),” the investigators wrote. “Graphically, the event curves crossed around 5 months, and corresponding HRs of 0.99 (0.71-1.37) and 1.61 (0.95-2.73) before and after 5 months, respectively”

They noted that among those who survived beyond 30 days, the primary outcome occurred more frequently between day 30 and 1-year in the restrictive group (HR, 1.44; 95% CI, 1.01-2.03).

Across the entire ITT population, all-cause death occurred in 79 restrictive patients (23.1%) and 66 (20.4%) liberal patients (HR, 1.13; 95% CI, 0.82-1.57).

Non-fatal stroke occurred in 7 (2.0%) in the restrictive group and 6 (1.8%) in the liberal group (HR, 1.14; 95% CI, 0.38-3.43). 

And emergency revascularization occurred in 17 (5.0%) and 14 (4.3%), respectively (HR, 1.13; 0.56-2.31).

The findings were consistent among the per protocol population (n = 659). Patients in the restrictive cohort similarly experienced higher rates of MACE (HR, 1.14; 95% CI, 0.86-1.51).

Currently, ACC guideliness recommend that a restrictive transfusion threshold of 8 g/dl is acceptable in hemodynamically stable patients—and that patient individual patients needs and contexts should be considered.

The guideline recommendations need to be the same,” González-Juanatey told HCPLive® in an interview. “In stable patients, you can adapt your transfusion strategy. It depends—probably you may need a more integrative approach.”

He indicated a need to follow-up with these seemingly inconclusive findings. As such, he mentioned the ongoing MINT trial, which is of similar design and will include 3000 patients undergoing randomization to either transfusion strategy.

The study, “One-year Follow-up Of The Reality Randomized Clinical Trial : Effect Of A Restrictive Vs Liberal Blood Transfusion Strategy On Major Cardiovascular Events Among Patients With Acute Myocardial Infarction And Anemia,” was presented at ACC 2021.