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Restricted Blood Transfusion Safe for Heart Patients With Anemia

by Dr. Meenakshy Varier on Sep 3 2020 3:48 PM

Restricted Blood Transfusion Safe for Heart Patients With Anemia
Using the restrictive strategy for blood transfusion in anemic heart attack patients helps save blood with no negative impact on clinical outcomes, in comparison to the liberal blood transfusion strategy. Restrictive strategy withholds transfusion of blood unless hemoglobin drops to 8 g/dL while liberal strategy indicates transfusion as soon as hemoglobin drops below 10 g/dL.
Anemia affects approximately 5-10% of patients with myocardial infarction and is an independent predictor of cardiac events and increased mortality. The antiplatelet and anticoagulant medications used to treat myocardial infarction raise the risk of bleeding, which in turn elevates the risk of anemia and mortality.

However, there is uncertainty over the benefits of blood transfusion in these patients. Observational studies have reported that transfusion is associated with a higher rate of mortality in patients with myocardial infarction. The optimal transfusion strategy in patients with acute myocardial infarction and anemia is also unclear. Only two very small randomized trials have been conducted, with conflicting results.

REALITY is the largest randomized trial comparing a restrictive versus a liberal blood transfusion strategy in myocardial infarction patients with anemia. In the restrictive strategy, transfusion was withheld unless haemoglobin dropped to 8 g/dL. In the liberal strategy, transfusion was given as soon as haemoglobin was 10 g/dL or below. Previous trials have compared these two strategies in other settings such as gastrointestinal bleeding, cardiac surgery, or non-cardiac surgery, but patients with acute myocardial infarction were excluded.

There were two primary endpoints. The primary clinical endpoint was a composite of major adverse cardiac events (MACE) at 30 days, including all-cause death, myocardial infarction, stroke, and emergency percutaneous coronary intervention (PCI) prompted by myocardial ischemia. The cost-effectiveness endpoint was the incremental cost-effectiveness ratio (ICER) at 30 days.

Principal investigator Professor Philippe Gabriel Steg of Hospital Bichat, Paris, France explained the reasons for having both a clinical and cost-effectiveness outcome: "Our hypothesis was that in myocardial infarction patients with anemia, a restrictive strategy would be non-inferior to a liberal strategy with respect to clinical outcomes at 30 days but would be less costly."

The trial was conducted in 35 hospitals in France and Spain. It enrolled 668 patients with acute myocardial infarction and anemia (haemoglobin 10 g/dL or below, but above 7 g/dL) at any time during admission. Patients were randomly allocated to the restrictive or liberal transfusion strategy and followed-up for 30 days.

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The restrictive transfusion strategy was non-inferior to the liberal strategy in preventing 30-day MACE. The primary clinical outcome occurred in 36 patients (11.0%) allocated to the restrictive strategy and 45 patients (14.0%) patients allocated to the liberal strategy (difference -3.0%; 95% confidence interval [CI] -8.4% to 2.4%). The relative risk of 30-day MACE with the restrictive versus liberal strategy was 0.79.

Cost-effectiveness analysis indicated that the restrictive strategy had an 84% probability of being cost-saving while improving clinical outcomes, i.e. "dominant" from a medico-economic standpoint.

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Regarding safety, compared to patients receiving the liberal strategy, those allocated to the restrictive strategy were significantly less likely to develop an infection (restrictive 0.0% vs. liberal 1.5%; p=0.03) or acute lung injury (restrictive 0.3% vs. liberal 2.2%; p=0.03).

Professor Steg said: "Blood is a precious resource, and transfusion is costly, logistically cumbersome, and has side effects. The REALITY trial supports the use of a restrictive strategy for blood transfusion in myocardial infarction patients with anemia. The restrictive strategy saves blood, is safe, and is at least as effective in preventing 30-day cardiac events compared to a liberal strategy while saving money."

Source-Eurekalert


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