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A Systematic Review and Meta-analysis of Randomized Controlled Trials Comparing Intraoperative Red Blood Cell Transfusion Strategies
Lenet T, Baker L, Park L, Vered M, Zahrai A, Shorr R, Davis A, McIsaac DI, Tinmouth A, Fergusson DA, et al
Annals of surgery. 2021
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Editor's Choice
Abstract
OBJECTIVE The objective of this work was to carry out a meta-analysis of RCTs comparing intraoperative RBC transfusion strategies to determine their impact on postoperative morbidity, mortality, and blood product use. SUMMARY OF BACKGROUND DATA RBC transfusions are common in surgery and associated with widespread variability despite adjustment for casemix. Evidence-based recommendations guiding RBC transfusion in the operative setting are limited. METHODS The search strategy was adapted from a previous Cochrane Review. Electronic databases were searched from January 2016 to February 2021. Included studies from the previous Cochrane Review were considered for eligibility from before 2016. RCTs comparing intraoperative transfusion strategies were considered for inclusion. Co-primary outcomes were 30-day mortality and morbidity. Secondary outcomes included intraoperative and perioperative RBC transfusion. Meta-analysis was carried out using random-effects models. RESULTS Fourteen trials (8641 patients) were included. One cardiac surgery trial accounted for 56% of patients. There was no difference in 30-day mortality [relative risk (RR) 0.96, 95% confidence interval (CI) 0.71-1.29] and pooled postoperative morbidity among the studied outcomes when comparing restrictive and liberal protocols. Two trials reported worse composite outcomes with restrictive triggers. Intraoperative (RR 0.53, 95% CI 0.43-0.64) and perioperative (RR 0.70, 95% CI 0.62-0.79) blood transfusions were significantly lower in the restrictive group compared to the liberal group. CONCLUSIONS Intraoperative restrictive transfusion strategies decreased perioperative transfusions without added postoperative morbidity and mortality in 12/14 trials. Two trials reported worse outcomes. Given trial design and generalizability limitations, uncertainty remains regarding the safety of broad application of restrictive transfusion triggers in the operating room. Trials specifically designed to address intraoperative transfusions are urgently needed.
PICO Summary
Population
Adult patients undergoing surgery (14 studies, n= 8,641).
Intervention
Restrictive blood transfusion strategy.
Comparison
Liberal blood transfusion strategy.
Outcome
There was no difference in 30-day mortality relative risk (RR) 0.96, and pooled postoperative morbidity among the studied outcomes when comparing restrictive and liberal protocols. Two trials reported worse composite outcomes with restrictive triggers. Intraoperative (RR 0.53) and perioperative (RR 0.70) blood transfusions were significantly lower in the restrictive group compared to the liberal group.
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Intraoperative Red Blood Cell Transfusion Decision-Making: A systematic Review of Guidelines
Baker L, Park L, Gilbert R, Ahn H, Martel A, Lenet T, Davis A, McIsaac DI, Tinmouth A, Fergusson DA, et al
Annals of surgery. 2020
Abstract
OBJECTIVES The objective of this work was to carry out a systematic review of clinical practice guidelines (CPGs) pertaining to intraoperative red blood cell (RBC) transfusions, in terms of indications, decision-making, and supporting evidence base. SUMMARY BACKGROUND DATA Red blood cell (RBC) transfusions are common during surgery and there is evidence of wide variability in practice. METHODS Major electronic databases (MEDLINE, EMBASE, and CINAHL), guideline clearinghouses and Google Scholar were systematically searched from inception to January 2019 for CPGs pertaining to indications for intraoperative RBC transfusion. Eligible guidelines were retrieved and their quality assessed using AGREE II. Relevant recommendations were abstracted and synthesized to allow for a comparison between guidelines. RESULTS Ten guidelines published between 1992 and 2018 provided indications for intraoperative transfusions. No guideline addressed intraoperative transfusion decision-making as its primary focus. Six guidelines provided criteria for transfusion based on hemoglobin (range 6.0-10.0 g/dL) or hematocrit (<30%) triggers. In the absence of objective transfusion rules, CPGs recommended considering other parameters such as blood loss (n = 7), signs of end organ ischemia (n = 5), and hemodynamics (n = 4). Evidence supporting intraoperative recommendations was extrapolated primarily from the non-operative setting. There was wide variability in the quality of included guidelines based on AGREE II scores. CONCLUSION This review has identified several clinical practice guidelines providing recommendations for intraoperative transfusion. The existing guidelines were noted to be highly variable in their recommendations and to lack a sufficient evidence base from the intraoperative setting. This represents a major knowledge gap in the literature.
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Efficacy and Safety of Tranexamic Acid in Major Non-Cardiac Surgeries at High Risk for Transfusion: A Systematic Review and Meta-Analysis
Houston BL, Uminski K, Mutter T, Rimmer E, Houston DS, Menard CE, Garland A, Ariano R, Tinmouth A, Abou-Setta AM, et al
Transfusion medicine reviews. 2019
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Editor's Choice
Abstract
Tranexamic acid (TXA) reduces transfusion requirements in cardiac surgery and total hip and knee arthroplasty, where it has become standard of care. Our objective is to determine the efficacy and safety of TXA in other surgeries associated with a high risk for red blood cell (RBC) transfusion. We identified randomized controlled trials in Medline, Embase, CENTRAL, and CAB abstracts from inception to June 2019. We included trials evaluating intraoperative IV TXA in adult patients undergoing a non-cardiac and non-hip and knee arthroplasty surgeries at high-risk for RBC transfusion, defined as a baseline transfusion rate ≥5% in comparator arm. We assessed risk of bias using the Cochrane Risk of Bias tool. We used GRADE methodology to assess certainty of evidence. From 8565 citations identified, we included 69 unique trials, enrolling 6157 patients. TXA reduces both the proportion of patients transfused RBCs (relative risk (RR) 0.59; 95% confidence interval (CI) 0.48 to 0.72; low certainty evidence) and the volume of RBC transfused (MD -0.51 RBC units; 95%CI -0.13 to -0.9 units; low certainty evidence) when compared to placebo or usual care. TXA was not associated with differences in deep vein thrombosis, pulmonary embolism, all-cause mortality, hospital length of stay, need for re-operation due to hemorrhage, myocardial infarction, stroke or seizure. In patients undergoing a broad range of non-cardiac and non-hip and knee arthroplasty surgeries at high risk for RBC transfusion, perioperative TXA reduced exposure to RBC transfusion. No differences in thrombotic outcomes were identified; however, summary effect estimates were limited by lack of systemic screening and short duration of follow-up.
PICO Summary
Population
Adult patients undergoing a non-cardiac and non-hip and knee arthroplasty surgeries at high-risk for RBC transfusion, (69 studies, n=6157).
Intervention
Intraoperative IV tranexamic acid (TXA).
Comparison
Placebo, usual care and active comparators.
Outcome
TXA reduces both the proportion of patients transfused RBCs (relative risk (RR) 0.59 and the volume of RBC transfused (MD -0.51 RBC units) when compared to placebo or usual care. TXA was not associated with differences in deep vein thrombosis, pulmonary embolism, all-cause mortality, hospital length of stay, need for re-operation due to hemorrhage, myocardial infarction, stroke or seizure. In patients undergoing a broad range of non-cardiac and non-hip and knee arthroplasty surgeries at high risk for RBC transfusion, perioperative TXA reduced exposure to RBC transfusion. No differences in thrombotic outcomes were identified; however, summary effect estimates were limited by lack of systemic screening and short duration of follow-up.
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Exclusion criteria and adverse events in perioperative trials of tranexamic acid in cardiac surgery: a systematic review and meta-analysis
Khair S, Perelman I, Yates J, Taylor J, Lampron J, Tinmouth A, Saidenberg E
Canadian journal of anaesthesia = Journal canadien d'anesthesie. 2019
Abstract
PURPOSE Tranexamic acid (TXA) reduces perioperative blood loss and transfusion requirement following cardiac surgery. Nevertheless, TXA remains underutilized because of concerns regarding development of adverse events. We conducted a systematic review to determine which patients are commonly excluded from TXA cardiac surgery clinical trials to determine if there are patient groups lacking safety data on TXA. METHODS The databases Medline, EMBASE, and the Cochrane Central Register of Controlled Trials were searched until September 2017. Eligible studies were randomized-controlled trials (RCTs) administering systemic TXA perioperatively to patients undergoing any cardiac surgery. Our primary outcome was the exclusion criteria for each RCT, and the secondary endpoint was TXA safety. A descriptive synthesis was performed to analyze the exclusion criteria. TXA safety was assessed with meta-analysis. PRINCIPAL FINDINGS Seventy eligible RCTs were included. The most common reasons for excluding patients from TXA cardiac surgery trials were major hepatic, renal, or cardiac comorbidities (76% of studies). Meta-analysis showed that TXA did not increase the risk of adverse events compared with placebo or no intervention (risk ratio, 0.97; 95% confidence interval, 0.88 to 1.07), including thrombosis and seizure. CONCLUSION We found that systemic TXA is safe to use in cardiac surgery. Certain patient groups are frequently excluded from TXA cardiac surgery trials, and may consequently have limited efficacy and safety data on TXA. Further research in these patient groups may be needed; nevertheless, for many patient populations there are sufficient data to inform evidence-based guidelines for TXA use in cardiac surgery. TRIAL REGISTRATION PROSPERO (CRD42017060971); registered 4 April, 2017.
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Exclusion criteria and adverse events in perioperative trials of tranexamic acid: a systematic review and meta-analysis
Yates J, Perelman I, Khair S, Taylor J, Lampron J, Tinmouth A, Saidenberg E
Transfusion. 2018
Abstract
BACKGROUND Tranexamic acid (TXA) is an inexpensive therapy effective at minimizing perioperative blood loss and transfusion. However, it remains underutilized due to safety concerns. To date, no evidence-based guidelines exist identifying which patients should not receive TXA therapy. This study determined patient groups for whom safety information regarding TXA is lacking due to common exclusion from perioperative TXA trials. STUDY DESIGN AND METHODS A systematic review searching the databases Medline, EMBASE, CENTRAL, and Clinicaltrials.gov was performed. Randomized controlled trials (RCTs) administering systemic TXA perioperatively to elective or emergent surgery patients were eligible. Our primary outcome was to describe exclusion criteria of RCTs, and the secondary outcome was TXA safety. A descriptive synthesis of exclusion criteria was performed, and TXA safety was assessed by meta-analysis. RESULTS A total of 268 eligible RCTs were included. Meta-analysis showed that systemic TXA did not increase risk of adverse events compared to placebo or no intervention (relative risk, 1.05; 95% confidence interval, 0.99-1.12). Patient groups commonly excluded from perioperative TXA trials, and thus potentially lacking TXA safety data, were those with major comorbidities, a history of thromboembolism, medication use affecting coagulation, TXA allergy, and coagulopathy. Exclusion of patients with major comorbidities may not be necessary; we showed that the risk of adverse events was similar in studies that excluded patients with major comorbidities and those that did not. CONCLUSION Sufficient evidence exists to develop perioperative guidelines for TXA use in many populations. Further studies evaluating perioperative TXA use in patients with a history of thromboembolism are warranted.
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The impact of perioperative red blood cell transfusions in patients undergoing liver resection: a systematic review
Bennett S, Baker LK, Martel G, Shorr R, Pawlik TM, Tinmouth A, McIsaac DI, Hebert PC, Karanicolas PJ, McIntyre L, et al
Hpb : the Official Journal of the International Hepato Pancreato Biliary Association. 2017;19((4):):321-330
Abstract
BACKGROUND Liver resection is associated with a high proportion of red blood cell transfusions. There is a proposed association between perioperative transfusions and increased risk of complications and tumor recurrence. This study reviews the evidence of this association in the literature. METHODS The Medline, EMBASE, and Cochrane databases were searched for clinical trials or observational studies of patients undergoing liver resection that compared patients who did and did not receive a perioperative red blood cell transfusion. Outcomes were mortality, complications, and cancer survival. RESULTS Twenty-two studies involving 6832 patients were included. All studies were retrospective, with no clinical trials. No studies were scored as low risk of bias. The overall proportion of patients transfused was 38.3%. After multivariate analysis, 1 of 5 studies demonstrated an association between transfusion and increased mortality; 5 of 6 demonstrated an association between transfusion and increased complications; and 10 of 18 demonstrated an association between transfusion and decreased cancer survival. CONCLUSION This review supports the evidence linking perioperative blood transfusions to negative outcomes. The most convincing association was with post-operative complications, some association with long-term cancer outcomes, and no convincing association with mortality. These findings support the initiation, and further study, of restrictive transfusion protocols.
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Trial of feedback on blood use
Kaufman RM, Stanworth S, Taljaard M, Yazer MH, Reeves C, Delaney M, Jackups R, Li Y, Cohn CS, Tinmouth A, et al
Transfusion. 2016;56((S4)):30A.. s68-030j.
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The effects of lysine analogs during pelvic surgery: a systematic review and meta-analysis
Breau RH, Kokolo MB, Punjani N, Cagiannos I, Beck A, NiznickN, Buenaventura C, Cowan J, Knoll G, Momoli F, et al
Transfusion Medicine Reviews. 2014;28((3):):145-55.
Abstract
Pelvic vasculature is complex and inconsistent while pelvic bones impede access to pelvic organs. These anatomical characteristics render pelvic surgery inherently difficult, and some of these procedures are frequently associated with blood loss that necessitates blood transfusion. The aim of this study was to review the literature on the use of lysine analogs to prevent bleeding and blood transfusion during pelvic surgery. The objective of this study was to assess the safety and efficacy of lysine analogs during pelvic surgery. A systematic literature search was performed using Medline, Cochrane Register of Clinical Trials, Embase, and the reference lists of relevant articles. Randomized controlled trials or observational cohort studies comparing a lysine analog to placebo or standard care were included. Outcomes collected were blood transfusion, blood loss, thromboembolic adverse events (myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism), nonthromboembolic adverse events, and death. There were no language limitations. Fifty-six articles reported on 68 comparisons between a lysine analog and an inactive comparator, involving a total of 7244 patients published between 1961 and 2013. Thirty-nine studies evaluated urologic procedures, and 21 evaluated gynecologic procedures. Thirty-six studies (60%) were published before 1980. Of the 43 randomized comparisons, only 30 (44%) had a score of 3 or higher on Jadad's 5-point scale of methodological quality. Among randomized trials, lysine analogs reduced the risk of blood transfusion (pooled odds ratio [OR], 0.47; 95% confidence interval [CI], 0.35-0.64) and blood loss (pooled OR, 0.22; 95% CI, 0.18-0.27). There was a small statistically insignificant increased risk of thromboembolic events (pooled OR, 1.07; 95% CI, 0.72-1.59) and no-thrombotic serious adverse events (pooled OR, 1.11; 95% CI, 0.67-1.83). In the 17 randomized trials published since the year 2000, only 6 thrombotic events were reported, 4 of which occurred in the placebo arm. Lysine analogs did not increase risk of death (pooled OR, 0.91; 95% CI, 0.34-2.48). These results are significant as they indicate that lysine analogs significantly reduce blood loss and blood transfusion during pelvic surgery. Although there does not appear to be a large increase in the risk of thromboembolic and nonthrombotic adverse events, more data are required to definitively assess these outcomes. Based on this review, lysine analogs during pelvic surgery seem to reduce bleeding and blood transfusion requirements. Although there does not seem to be a significant risk of adverse effects, larger studies would help clarify risks, if any, associated with lysine analog use. Copyright © 2014 Elsevier Inc. All rights reserved.
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Risks of harms using antifibrinolytics in cardiac surgery: systematic review and network meta-analysis of randomised and observational studies
Hutton B, Joseph L, Fergusson D, Mazer CD, Shapiro S, Tinmouth A
Bmj.. 2012;345:e5798.
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Abstract
OBJECTIVE To estimate the relative risks of death, myocardial infarction, stroke, and renal failure or dysfunction between antifibrinolytics and no treatment following the suspension of aprotinin from the market in 2008 for safety reasons and its recent reintroduction in Europe and Canada. DESIGN Systematic review and network meta-analysis. DATA SOURCES A Cochrane review of antifibrinolytic treatments was chosen as the starting point for this systematic review. Medline, Embase, and the Cochrane register of trials were searched with no date restrictions for observational evidence. STUDY SELECTION Propensity matched or adjusted observational studies with two or more of the interventions of interest (aprotinin, tranexamic acid, epsilon-aminocaproic acid, and no treatment) that were carried out in patients undergoing cardiac surgery. DATA ANALYSIS Network meta-analysis was used to compare treatments, and odds ratios with 95% credible intervals were estimated. Meta-analyses were carried out for randomised controlled trials alone and for randomised controlled trials with observational studies. RESULTS 106 randomised controlled trials and 11 observational studies (43 270 patients) were included. Based on the results from analysis of randomised controlled trials, tranexamic acid was associated on average with a reduced risk of death compared with aprotinin (odds ratio 0.64, 95% credible interval 0.41 to 0.99). When observational data were incorporated, comparisons showed an increased risk of mortality with aprotinin on average relative to tranexamic acid (odds ratio 0.71, 95% credible interval 0.50 to 0.98) and epsilon-aminocaproic acid (0.60, 0.43 to 0.87), and an increased risk of renal failure or dysfunction on average relative to all comparators: odds ratio 0.66 (95% credible interval 0.45 to 0.88) compared with no treatment, 0.66 (0.48 to 0.91) versus tranexamic acid, and 0.65 (0.45 to 0.88) versus epsilon-aminocaproic acid. CONCLUSION Although meta-analyses of randomised controlled trials were largely inconclusive, inclusion of observational data suggest concerns remain about the safety of aprotinin. Tranexamic and epsilon-aminocaproic acid are effective alternatives that may be safer for patients.