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.
Highlights
Anemia is frequent in patients with acute myocardial infarction (AMI), with the reported rates of 15–43% [1], because of invasive procedures and antithrombotic therapy [2]
There was no significant difference in follow-up mortality between the two groups (RR, 0.89 [95% confidence intervals (CI) = 0.56–1.42]; P = 0.62; I2 = 50%), while 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; I2 = 41%) (Supplementary Figure 2)
The present study showed no differences in overall mortality and follow-up mortality between the restrictive and liberal transfusion in AMI patients with anemia
Summary
Anemia is frequent in patients with acute myocardial infarction (AMI), with the reported rates of 15–43% [1], because of invasive procedures and antithrombotic therapy [2]. Red blood cell (RBC) transfusion increases oxygen delivery, rapidly improves symptoms in patients with acute myocardial ischemia, and is commonly used in clinical practice [4]. It is essential to select the optimal transfusion strategy in AMI patients with anemia. Observational studies have yielded conflicting results [11,12,13] and only two previous small randomized clinical trials (RCTs) (including 45 and 110 patients) have compared transfusion strategies in patients with AMI [14, 15]. The first multicenter RCT with a relatively large sample size has compared liberal and restrictive RBC transfusion strategies in such settings [16], and the results showed that the restrictive transfusion resulted in a non-inferior rate of adverse outcomes after 30 days
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