Transfusion in AMI: More or Less?

By Kaitlyn Dmyterko, Medical Correspondent on

A restrictive transfusion strategy may no longer be inferior to a liberal transfusion strategy in preventing one-year MACE rates in acute MI and anemia patients, results of a REALITY study analysis presented at the 70th annual meeting of the American College of Cardiology (ACC), found.

José González-Juanatey, MD, of the University Hospital, Santiago de Compostela, Spain, presented the results of this joint French and Spanish randomized, open-label non-inferiority trial that assessed one-year follow-up of the REALITY randomized clinical trial results.

The REALITY study, published in JAMA in February 2021, assessed the safety and efficacy of a restrictive (Hgb ≤8 g/dL, target Hgb 8-10 g/dL) versus liberal (Hgb ≤10 g/dL, goal Hgb >11 g/dL) red blood cell (RBC) transfusion strategy among 688 patients with acute MI and anemia that had hemoglobin levels between 7 and 10 g/dL. Investigators found that the primary outcome (all-cause death, stroke, recurrent MI, or emergency revascularization in 30 days) occurred in 11% of patients undergoing restrictive transfusion strategies versus 14% enrolled into liberal transfusion strategies.

However, one-year results showed that the primary outcome occurred in 111/342 patients in the restrictive transfusion strategy group versus 92/324 in the liberal transfusion strategy group (HR 1.16; 95% CI, 0.88-1.53).

“The restrictive strategy did not achieve non-inferiority at 1-year,” noted González-Juanatey. In fact, investigators found that the event curves crossed around the 5-month mark showing more frequent events in the liberal transfusion strategy arm before five months (HR 0.99, CI 0.71-1.37), and more frequent events in the restrictive transfusion arm after five months (HR 1.61, CI 0.95-2.73).

Additionally, investigators found that the primary outcomes occurred more frequently between day 30 and one-year in the restrictive group (HR 1.44, 95% CI 1.01-2.03). Patients who underwent the liberal transfusion strategy fared significantly better than those undergoing restrictive transfusion strategies in patients alive after 30 days.

Rates of “MACE were significantly higher in the restrictive group compared with the liberal group on all the components of the primary endpoints,” noted González-Juanatey.

He concluded that, “Further studies, such as the ongoing MINT trial (NCT02981407), are required to definitively establish the optimal management of anemia in patients with acute myocardial infarction.”

The restrictive transfusion strategy when compared with a liberal transfusion strategy did not achieve clinical non-inferiority in outcomes events at 1 year.

Discussant Dr. Christopher Granger, Duke University Medical Center and Duke Clinical Research Institute, called this a “very provocative presentation,” and said, “Current and previous data has shown that a more restrictive transfusion strategy, across all medical conditions, makes sense as the standard approach.” However, he said, “I think what you have done in this study is make us be humble about the data from observational studies and show that we really need these randomized trials.”

Granger questioned whether the current results should be a heads up to MINT study investigators, who are conducting a nearly 3,000 patient study to test the superiority of the liberal transfusion strategy versus the restrictive transfusion strategy in acute MI and anemia patients after 30 days.

“What you suggest here is that there may be different short-term and long-term effects of transfusion strategy,” said Granger. “I wonder if this should be a message to the MINT investigators to extend their follow up to at least one year to be sure they are capturing that data.”

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