Restrictive vs. Liberal Red Blood Cell Transfusion Strategy in Patients With Acute Myocardial Infarction and Anemia: A Systematic Review and Meta-Analysis

Abstract

Objective: Anemia is frequent in patients with acute myocardial infarction (AMI), and the optimal red blood cell transfusion strategy for AMI patients with anemia is still controversial. We aimed to compare the efficacy of restrictive and liberal red cell transfusion strategies in AMI patients with anemia.Methods: We systematically searched PubMed, EMBASE, Web of Science, Cochrane Library, and Clinicaltrials.gov, from their inception until March 2021. Studies designed to compare the efficacy between restrictive and liberal red blood cell transfusion strategies in patients with AMI were included. The primary outcome was all-cause mortality, including overall mortality, in-hospital or follow-up mortality. Risk ratios (RR) with 95% confidence intervals (CI) were presented and pooled by random-effects models.Results: The search yielded a total of 6,630 participants in six studies. A total of 2,008 patients received restrictive red blood cell transfusion while 4,622 patients were given liberal red blood cell transfusion. No difference was found in overall mortality and follow-up mortality between restrictive and liberal transfusion groups (RR = 1.07, 95% CI = 0.82–1.40, P = 0.62; RR = 0.89, 95% CI = 0.56–1.42, P = 0.62). However, restrictive transfusion tended to have a higher risk of in-hospital mortality compared with liberal transfusion (RR = 1.22, 95% CI = 1.00–1.50, P = 0.05). No secondary outcomes, including follow-up reinfarction, stroke, and acute heart failure, differed significantly between the two groups. In addition, subgroup analysis showed no differences in overall mortality between the two groups based on sample size and design.Conclusion: Restrictive and liberal red blood cell transfusion have a similar effect on overall mortality and follow-up mortality in AMI patients with anemia. However, restrictive transfusion tended to have a higher risk of in-hospital mortality compared with liberal transfusion. The findings suggest that transfusion strategy should be further evaluated in future studies.

Extracorporeal Membrane Oxygenation Patient Outcomes Following Restrictive Blood Transfusion Protocol

“…Previous literature has investigated the impact of transfusion thresholds on mortality in the general ICU population. However, the effects of a restrictive transfusion protocol for ECMO patients are underreported in the literature (3, 4, 8, 12). The most important finding of this study was that a restrictive transfusion threshold was not associated with decreased rates of survival for patients on venoarterial ECMO, venovenous ECMO, or ECPR.…”

“…A randomized controlled clinical trial of non-ECMO critical care patients by the Canadian Critical Care Trials Group first reported that a RBC restrictive transfusion strategy of 7 g/dL was not associated with significantly increased patient mortality compared with a liberal transfusion strategy of 10 g/dL (8). Since this landmark study, multiple studies in the critical care patient population have also reported noninferior patient outcomes with a restrictive transfusion strategy (3,(12)(13)(14)(15)(16). Due to the limited clinical evidence of transfusion protocols in the ECMO population, many established transfusion protocols are currently based on extrapolated knowledge from research in critically ill patients (3).…”

Coagulation and Transfusion Updates From 2021

“…[45][46][47][48][49] Combined with evidence suggesting RBC transfusion may not eliminate the risk of organ dysfunction and is associated with impaired outcomes, transfusion best practices remain elusive. 2,43,50,51 Contributing to uncertainty, 2 large randomized controlled trials in cardiac surgery did not show an impaired outcome with a more liberal transfusion strategy compared to a restrictive regimen. 47,48 Adding even more confounders, a recent large retrospective analysis in healthcare data from >700,000 patients showed that non-White ethnicity was associated with increased rates of blood transfusion.…”