1.
Impact of restrictive red blood cell transfusion strategy on thrombosis-related events: A meta-analysis and systematic review
Maimaitiming M, Zhang C, Xie J, Zheng Z, Luo H, Ooi OC
Vox sanguinis. 2022
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Editor's Choice
Abstract
BACKGROUND AND OBJECTIVES There is an ongoing controversy regarding the risks of restrictive and liberal red blood cell (RBC) transfusion strategies. This meta-analysis assessed whether transfusion at a lower threshold was superior to transfusion at a higher threshold, with regard to thrombosis-related events, that is, whether these outcomes can benefit from a restrictive transfusion strategy is debated. MATERIALS AND METHODS We searched PubMed, Cochrane Central Register of Controlled Trials and Scopus from inception up to 31 July 2021. We included randomized controlled trials (RCTs) in any clinical setting that evaluated the effects of restrictive versus liberal RBC transfusion in adults. We used random-effects models to calculate the risk ratios (RRs) and 95% confidence intervals (CIs) based on pooled data. RESULTS Thirty RCTs involving 17,334 participants were included. The pooled RR for thromboembolic events was 0.65 (95% CI 0.44-0.94; p = 0.020; I(2) = 0.0%, very low-quality evidence), favouring the restrictive strategy. There were no significant differences in cerebrovascular accidents (RR = 0.83; 95% CI 0.64-1.09; p = 0.180; I(2) = 0.0%, very low-quality evidence) or myocardial infarction (RR = 1.05; 95% CI 0.87-1.26; p = 0.620; I(2) = 0.0%, low-quality evidence). Subgroup analyses showed that a restrictive (relative to liberal) strategy reduced (1) thromboembolic events in RCTs conducted in North America and (2) myocardial infarctions in the subgroup of RCTs where the restrictive transfusion threshold was 7 g/dl but not in the 8 g/dl subgroup (with a liberal transfusion threshold of 10 g/dl in both subgroups). CONCLUSIONS A restrictive (relative to liberal) transfusion strategy may be effective in reducing venous thrombosis but not arterial thrombosis.
PICO Summary
Population
Adult patients in any clinical setting (30 studies, n= 17,334).
Intervention
Restrictive red blood cell transfusion.
Comparison
Liberal red blood cell transfusion.
Outcome
The pooled risk ratio (RR) for thromboembolic events was 0.65 (very low-quality evidence), favouring the restrictive strategy. There were no significant differences in cerebrovascular accidents (RR= 0.83, very low-quality evidence) or myocardial infarction (RR= 1.05, low-quality evidence). Subgroup analyses showed that a restrictive (relative to liberal) strategy reduced thromboembolic events in trials conducted in North America, and myocardial infarctions in the subgroup of trials where the restrictive transfusion threshold was 7 g/dl but not in the 8 g/dl subgroup (with a liberal transfusion threshold of 10 g/dl in both subgroups).
2.
Restrictive vs. Liberal Red Blood Cell Transfusion Strategy in Patients With Acute Myocardial Infarction and Anemia: A Systematic Review and Meta-Analysis
Zhang Y, Xu Z, Huang Y, Ye Q, Xie N, Zeng L, Lian X, Dai Y, Chen J, He P, et al
Frontiers in cardiovascular medicine. 2021;8:736163
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Free full text
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Editor's Choice
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.
PICO Summary
Population
Patients with acute myocardial infarction and anaemia (6 studies, n= 6,630).
Intervention
Restrictive red blood cell transfusion strategy (n= 2,008).
Comparison
Liberal red blood cell transfusion strategy (n= 4,622).
Outcome
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]; RR= 0.89; 95% CI [0.56, 1.42]). 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]). 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.
3.
Effect of restrictive versus liberal transfusion strategies on outcomes in patients with cardiovascular disease in a non-cardiac surgery setting: systematic review and meta-analysis
Docherty AB, O'Donnell R, Brunskill S, Trivella M, Doree C, Holst L, Parker M, Gregersen M, Pinheiro de Almeida J, Walsh TS, et al
Bmj.. 2016;352:i1351.
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Free full text
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Full text
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Editor's Choice
Abstract
OBJECTIVE To compare patient outcomes of restrictive versus liberal blood transfusion strategies in patients with cardiovascular disease not undergoing cardiac surgery. DESIGN Systematic review and meta-analysis. DATA SOURCES Randomised controlled trials involving a threshold for red blood cell transfusion in hospital. We searched (to 2 November 2015) CENTRAL, Medline, Embase, CINAHL, PubMed, LILACS, NHSBT Transfusion Evidence Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, ISRCTN Register, and EU Clinical Trials Register. Authors were contacted for data whenever possible. TRIAL SELECTION Published and unpublished randomised controlled trials comparing a restrictive with liberal transfusion threshold and that included patients with cardiovascular disease. DATA EXTRACTION AND SYNTHESIS Data extraction was completed in duplicate. Risk of bias was assessed using Cochrane methods. Relative risk ratios with 95% confidence intervals were presented in all meta-analyses. Mantel-Haenszel random effects models were used to pool risk ratios. MAIN OUTCOME MEASURES 30 day mortality, and cardiovascular events. RESULTS 41 trials were identified; of these, seven included data on patients with cardiovascular disease. Data from a further four trials enrolling patients with cardiovascular disease were obtained from the authors. In total, 11 trials enrolling patients with cardiovascular disease (n=3033) were included for meta-analysis (restrictive transfusion, n=1514 patients; liberal transfusion, n=1519). The pooled risk ratio for the association between transfusion thresholds and 30 day mortality was 1.15 (95% confidence interval 0.88 to 1.50, P=0.50), with little heterogeneity (I(2)=14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials; risk ratio 1.78, 95% confidence interval 1.18 to 2.70, P=0.01, I(2)=0%). CONCLUSIONS The results show that it may not be safe to use a restrictive transfusion threshold of less than 80 g/L in patients with ongoing acute coronary syndrome or chronic cardiovascular disease. Effects on mortality and other outcomes are uncertain. These data support the use of a more liberal transfusion threshold (>80 g/L) for patients with both acute and chronic cardiovascular disease until adequately powered high quality randomised trials have been undertaken in patients with cardiovascular disease. REGISTRATION PROSPERO CRD42014014251.Copyright Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
PICO Summary
Population
Patients with cardiovascular disease not undergoing cardiac surgery (11 randomised controlled trials, n= 3,033).
Intervention
Restrictive transfusion strategy (n= 1,514).
Comparison
Liberal transfusion strategy (n= 1,519).
Outcome
The pooled risk ratio for the association between transfusion thresholds and 30-day mortality was 1.15 (95% confidence interval (CI): 0.88 to 1.50), with little heterogeneity (I2= 14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials; risk ratio: 1.78, 95% CI: 1.18 to 2.70, I2= 0%).