Tranexamic acid reduces blood loss in off-pump coronary artery bypass surgery

Tranexamic acid for the reduction of bleeding during functional endoscopic sinus surgery

BACKGROUND

Chronic rhinosinusitis, with or without nasal polyps, can have a major impact on a person's quality of life. Treatment is usually conservative and may include nasal saline, intranasal corticosteroids, antibiotics or systemic corticosteroids. If these treatments fail endoscopic sinus surgery can be considered. During surgery, visibility of the surgical field is important for the identification of important anatomic landmarks and structures that contribute to safety. Impaired visualisation can lead to complications during surgery, inability to complete the operation or a longer duration of surgery. Different methods are used to decrease intraoperative bleeding, including induced hypotension, topical or systemic vasoconstrictors or total intravenous anaesthesia. Another option is tranexamic acid, an antifibrinolytic agent, which can be administered topically or intravenously.

OBJECTIVES

To assess the effects of peri-operative tranexamic acid versus no therapy or placebo on operative parameters in patients with chronic rhinosinusitis (with or without nasal polyps) who are undergoing functional endoscopic sinus surgery (FESS).

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Trials Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 10 February 2022.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing intravenous, oral or topical tranexamic acid with no therapy or placebo in the treatment of patients (adults and children) with chronic rhinosinusitis, with or without nasal polyps, undergoing FESS.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Primary outcome measures were surgical field bleeding score (e.g. Wormald or Boezaart grading system), intraoperative blood loss and significant adverse effects (seizures or thromboembolism within 12 weeks of surgery). Secondary outcomes were duration of surgery, incomplete surgery, surgical complications and postoperative bleeding (placing of packing or revision surgery) in the first two weeks after surgery. We performed subgroup analyses for methods of administration, different dosages, different forms of anaesthesia, use of thromboembolic prophylaxis and children versus adults. We evaluated each included study for risk of bias and used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included 14 studies in the review, with a total of 942 participants. Sample sizes in the included studies ranged from 10 to 170. All but two studies included adult patients (≥ 18 years). Two studies included children. Most studies had more male patients (range 46.6% to 80%). All studies were placebo-controlled and four studies had three treatment arms. Three studies investigated topical tranexamic acid; the other studies reported the use of intravenous tranexamic acid. For our primary outcome, surgical field bleeding score measured with the Boezaart or Wormald grading score, we pooled data from 13 studies. The pooled result demonstrated that tranexamic acid probably reduces the surgical field bleeding score, with a standardised mean difference (SMD) of -0.87 (95% confidence interval (CI) -1.23 to -0.51; 13 studies, 772 participants; moderate-certainty evidence). A SMD below -0.70 represents a large effect (in either direction). Tranexamic acid may result in a slight reduction in blood loss during surgery compared to placebo with a mean difference (MD) of -70.32 mL (95% CI -92.28 to -48.35 mL; 12 studies, 802 participants; low-certainty evidence). Tranexamic acid probably has little to no effect on the development of significant adverse events (seizures or thromboembolism) within 24 hours of surgery, with no events in either group and a risk difference (RD) of 0.00 (95% CI -0.02 to 0.02; 8 studies, 664 participants; moderate-certainty evidence). However, there were no studies reporting significant adverse event data with a longer duration of follow-up. Tranexamic acid probably results in little difference in the duration of surgery with a MD of -13.04 minutes (95% CI -19.27 to -6.81; 10 studies, 666 participants; moderate-certainty evidence). Tranexamic acid probably results in little to no difference in the incidence of incomplete surgery, with no events in either group and a RD of 0.00 (95% CI -0.09 to 0.09; 2 studies, 58 participants; moderate-certainty evidence) and likely results in little to no difference in surgical complications, again with no events in either group and a RD of 0.00 (95% CI -0.09 to 0.09; 2 studies, 58 participants; moderate-certainty evidence), although these numbers are too small to draw robust conclusions. Tranexamic acid may result in little to no difference in the likelihood of postoperative bleeding (placement of packing or revision surgery within three days of surgery) (RD -0.01, 95% CI -0.04 to 0.02; 6 studies, 404 participants; low-certainty evidence). There were no studies with longer follow-up.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence to support the beneficial value of topical or intravenous tranexamic acid during endoscopic sinus surgery with respect to surgical field bleeding score. Low- to moderate-certainty evidence suggests a slight decrease in total blood loss during surgery and duration of surgery. Whilst there is moderate-certainty evidence that tranexamic acid does not lead to more immediate significant adverse events compared to placebo, there is no evidence regarding the risk of serious adverse events more than 24 hours after surgery. There is low-certainty evidence that tranexamic acid may not change postoperative bleeding. There is not enough evidence available to draw robust conclusions about incomplete surgery or surgical complications.

Re-Evaluating the Effect of Preoperative Tranexamic Acid on Blood Loss and Field Quality During Rhinoplasty: A Randomized Double-Blinded Controlled Trial

BACKGROUND

Nowadays, minimizing the surgical complications of rhinoplasty has gained more importance. Results from previous trials show that Tranexamic acid (TXA) reduces intraoperative bleeding, one of the major complicating factors during rhinoplasty.

OBJECTIVE

To contribute to previous evidence by re-evaluating the efficacy of TXA, specifically in reducing intraoperative blood loss and increasing surgical field quality in rhinoplasty.

STUDY DESIGN AND METHODS

A randomized placebo-controlled trial was conducted (IRCT20111219008458N2). The outcomes included total intraoperative blood loss, measured by the total volume of fluid collected by suction and gauzes, subtracted by volume of used irrigation fluids, and the quality of surgical field, measured by surgeon's satisfaction on a 5-point Likert scale. Demographics, blood coagulation measures, and clinical data were also collected and were held as covariates in analysis. After blinding, randomization, and group allocations, the intervention group received TXA 10mg/kg and the placebo group normal saline in equal volumes.

RESULTS

Data of a total of 80 patients were gathered and analyzed. The total intraoperative blood loss was insignificantly lower (mean difference [95% CI]:  - 3.6 ( - 19.19, 11.99), P = 0.65) and surgeon's satisfaction was insignificantly higher (mean difference [95% CI]: 0.18 ( - 0.11, 0.46), P = 0.22) in TXA group. Results were confirmed by multivariable analysis.

CONCLUSION

In contrast to most of the previous studies, this study showed only a statistically insignificant decrease in total intraoperative blood loss in patients receiving TXA compared to placebo. Further studies are required to more precisely estimate the efficacy of TXA in reducing blood loss during rhinoplasty.

LEVEL OF EVIDENCE

LEVEL I, RANDOMIZED CONTROLLED TRIAL.: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Application of tissue-engineered interventions for coronary artery bypass grafts

Coronary artery bypass graft is one of the extensively conducted procedures to release occlusion in the coronary vessel. Various biological grafts are used for this purpose, superiorly, saphenous vein graft, if unavailable, other vessels in the body, with likewise characteristics are exploited for the purpose. The choice of graft is yet under discovery that could impeccably meet all the requirements. Variation in perioperative and postoperative results have given uneven clinical inferences of these conduits. Alternatively, tissue-engineering is also being applied in this area for clinical improvements. This review underlines some of the commonly used grafts for coronary artery bypass graft and advancements in tissue engineering for this purpose.

Different dose regimes and administration methods of tranexamic acid in cardiac surgery: a meta-analysis of randomized trials

BACKGROUND

The efficacy of tranexamic acid (TXA) to reduce perioperative blood loss and allogeneic blood transfusion in cardiac surgeries has been proved in previous studies, but its adverse effects especially seizure has always been a problem of concern. This meta-analysis aims to provide information on the optimal dosage and delivery method which is effective with the least adverse outcomes.

METHODS

We searched Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE for all relevant articles published before 2018/12/31. Inclusion criteria were adult patients undergoing elective heart surgeries, and only randomized control trials comparing TXA with placebo were considered. Two authors independently assessed trial quality and extracted relevant data.

RESULTS

We included 49 studies with 10,591 patients into analysis. TXA significantly reduced transfusion rate (RR 0.71, 95% CI 0.65 to 0.78, P<0.00001). The overall transfusion rate was 35%(1573/4477) for patients using TXA and 49%(2190/4408) for patients in the control group. Peri-operative blood loss (MD - 246.98 ml, 95% CI - 287.89 to - 206.06 ml, P<0.00001) and re-operation rate (RR 0.62, 95% CI 0.49 to 0.79, P<0.0001) were also reduced significantly. TXA usage did not increase risk of mortality, myocardial infarction, stroke, pulmonary embolism and renal dysfunction, but was associated with a significantly increase in seizure attack (RR 3.21, 95% CI 1.04 to 9.90, P = 0.04).The overall rate of seizure attack was 0.62%(21/3378) for patients using TXA and 0.15%(5/3406) for patients in the control group. In subgroup analysis, TXA was effective for both on-pump and off-pump surgeries. Topical application didn't reduce the need for transfusion requirement, while intravenous delivery no matter as bolus injection alone or bolus plus continuous infusion were effective. Intravenous high-dose TXA didn't further decrease transfusion rate compared with low-dose regimen, and increased the risk of seizure by 4.83 times. No patients in the low-dose group had seizure attack.

CONCLUSIONS

TXA was effective in reducing transfusion requirement in all kinds of cardiac surgeries. Low-dose intravenous infusion was the most preferable delivery method which was as effective as high-dose regimen in reducing transfusion rate without increasing the risk of seizure.

The safety and efficiency of intravenous administration of tranexamic acid in coronary artery bypass grafting (CABG): a meta-analysis of 28 randomized controlled trials

Background

The safety and efficiency of intravenous administration of tranexamic acid (TXA) in coronary artery bypass grafting (CABG) remains unconfirmed. Therefore, we conducted a meta-analysis on this topic.

Methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PUBMED and EMBASE for randomized controlled trials on the topic. The results of this work are synthetized and reported in accordance with the PRISMA statement.

Results

Twenty-eight studies met our inclusion criteria. TXA reduced the incidence of postoperative reoperation of bleeding (relative risk [RR], 0.46; 95% confidence interval [CI]; 0.31–0.68), the frequency of any allogeneic transfusion (RR, 0.64; 95% CI, 0.52–0.78) and the postoperative chest tube drainage in the first 24 h by 206 ml (95% CI − 248.23 to − 164.15). TXA did not significantly affect the incidence of postoperative cerebrovascular accident (RR, 0.93; 95%CI, 0.62–1.39), mortality (RR, 0.82; 95%CI, 0.53–1.28), myocardial infarction (RR, 0.90; 95%CI, 0.78–1.05), acute renal insufficiency (RR, 1.01; 95%CI, 0.77–1.32). However, it may increase the incidence of postoperative seizures (RR, 6.67; 95%CI, 1.77–25.20). Moreover, the subgroup analyses in on-pump and off-pump CABG, the sensitivity analyses in trials randomized more than 99 participants and sensitivity analyses that excluded the study with the largest number of participants further strengthened the above results.

Conclusions

TXA is effective to reduce reoperation for bleeding, blood loss and the need for allogeneic blood products in patients undergoing CABG without increasing prothrombotic complication. However, it may increase the risk of postoperative seizures.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0761-3) contains supplementary material, which is available to authorized users.

The effect of tranexamic acid to reduce blood loss and transfusion on off-pump coronary artery bypass surgery: A systematic review and cumulative meta-analysis

STUDY OBJECTIVE

To assess the safety and efficacy of tranexamic acid (TA) on off-pump coronary artery bypass (OPCAB) surgery.

DESIGN

Meta-analysis.

SETTING

Operating room, OPCAB surgery, all surgeries were elective measurements. Searching the following data sources respectively: PubMed/MEDLINE, the Cochrane Library, EMBASE and reference lists of identified articles, we performed a meta-analysis of postoperative 24h blood loss, postoperative allogeneic transfusion, re-operation for massive bleeding, postoperative mortality, and postoperative thrombotic complications.

MAIN RESULTS

Using electronic databases, we selected 15 randomized control trials (RCTs), carried out between 2003 and 2016, with a total of 1250 patients for our review. TA significantly reduced the postoperative 24h blood loss (mean difference -213.32ml, 95% confidence intervals, -247.20ml to -179.43ml; P<0.0001). And, TA also significantly reduced the risk of packed red blood cell (PRBCs) transfusion (risk ratio 0.62; 95% confidence intervals 0.51 to 0.76; P<0.0001) and fresh frozen plasma (FFP) transfusion (0.65; 0.52 to 0.81; P<0.001). There were no statistical significance on platelet transfusion (risk difference -0.00, 95% confidence interval -0.02 to 0.02; P=0.73) and re-operation (0.00, -0.02 to 0.02; P=1.00). No association was found between TA and morbility (risk difference -0.00, 95% confidence interval -0.02 to 0.02; P=0.99) and thrombotic complications (-0.01, -0.01 to 0.02; P=0.70).

CONCLUSIONS

TA reduced the probability of receiving a PRBCs and FFP transfusion during OPCAB surgery. And no association with postoperative death and thrombotic events was found. However, further trials with an appropriate sample size are required to confirm TA safety in OPCAB surgery.

Exclusion criteria and adverse events in perioperative trials of tranexamic acid: a systematic review and meta-analysis

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.

Diffuse alveolar hemorrhage and recombinant factor VIIa treatment in pediatric patients

Diffuse alveolar hemorrhage (DAH) is a life-threatening pulmonary complication in patients with hematologic malignancies or autoimmune disorders. The current treatment options, which include corticosteroids, transfusions, extracorporeal membrane oxygenation (ECMO), and immunosuppressants, have been limited and largely unsuccessful. Recombinant activated factor VII (rFVIIa) has been successfully administered, either systemically or bronchoscopically, to adults for the treatment of DAH, but there are few data on its use in pediatric patients. The current literature in the PubMed database was reviewed to evaluate the efficacy and risk of rFVIIa treatment for DAH in pediatric patients. This review discusses the diagnosis and treatment of DAH, as well as a new treatment paradigm that includes rFVIIa. Additionally, the risks and benefits of off-label use of rFVIIa in pediatric patients are discussed.

Tranexamic acid evokes pain by modulating neuronal excitability in the spinal dorsal horn

Tranexamic acid (TXA) is an antifibrinolytic agent widely used to reduce blood loss during surgery. However, a serious adverse effect of TXA is seizure due to inhibition of γ-aminobutyric acid (GABA) and glycine receptors in cortical neurons. These receptors are also present in the spinal cord, and antagonism of these receptors in spinal dorsal horn neurons produces pain-related phenomena, such as allodynia and hyperalgesia, in experimental animals. Moreover, some patients who are injected intrathecally with TXA develop severe back pain. However, the effect of TXA on spinal dorsal horn neurons remain poorly understood. Here, we investigated the effects of TXA by using behavioral measures in rats and found that TXA produces behaviors indicative of spontaneous pain and mechanical allodynia. We then performed whole-cell patch-clamp experiments that showed that TXA inhibits GABA_A and glycine receptors in spinal dorsal horn neurons. Finally, we also showed that TXA facilitates activation of the extracellular signal-regulated kinase in the spinal cord. These results indicated that TXA produces pain by inhibiting GABA_A and glycine receptors in the spinal dorsal horn.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

Systematic review, meta-analysis and meta-regression of the effect of tranexamic acid on surgical blood loss

Background

Tranexamic acid (TXA) reduces blood transfusion in surgery but the extent of the reduction in blood loss and how it relates to the dose of TXA is unclear.

Methods

A systematic review of randomized trials was performed. Data were extracted on blood loss from trials comparing intravenous TXA with no TXA or placebo in surgical patients. A Bayesian linear regression was used to describe the relationship between the reduction in blood loss with TXA and the extent of bleeding as measured by the mean blood loss in the control group. A meta-analysis of the log-transformed data was conducted to quantify the effect of TXA on blood loss, stratified by type of surgery, timing of TXA administration and trial quality. Meta-regression was used to explore the effect of TXA dosage.

Results

Data from 104 trials were examined. Although the absolute reduction in blood loss with TXA increased as surgical bleeding increased, the percentage reduction was similar. TXA reduced blood loss by 34 per cent (pooled ratio 0·66, 95 per cent confidence interval 0·65 to 0·67; P &lt; 0·001). The percentage reduction in blood loss with TXA differed by type of surgery, timing of TXA administration and trial quality, but the differences were small. The effect of TXA on blood loss did not vary over the range of doses assessed (5·5–300 mg/kg).

Conclusion

TXA reduces blood loss in surgical patients by about one-third. A total dose of 1 g appears to be sufficient for most adults. There is no evidence to support the use of high doses.

Effect of tranexamic acid on surgical bleeding: systematic review and cumulative meta-analysis

OBJECTIVE

To assess the effect of tranexamic acid on blood transfusion, thromboembolic events, and mortality in surgical patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Cochrane central register of controlled trials, Medline, and Embase, from inception to September 2011, the World Health Organization International Clinical Trials Registry Platform, and the reference lists of relevant articles.

STUDY SELECTION

Randomised controlled trials comparing tranexamic acid with no tranexamic acid or placebo in surgical patients. Outcome measures of interest were the number of patients receiving a blood transfusion; the number of patients with a thromboembolic event (myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism); and the number of deaths. Trials were included irrespective of language or publication status.

RESULTS

129 trials, totalling 10,488 patients, carried out between 1972 and 2011 were included. Tranexamic acid reduced the probability of receiving a blood transfusion by a third (risk ratio 0.62, 95% confidence interval 0.58 to 0.65; P<0.001). This effect remained when the analysis was restricted to trials using adequate allocation concealment (0.68, 0.62 to 0.74; P<0.001). The effect of tranexamic acid on myocardial infarction (0.68, 0.43 to 1.09; P = 0.11), stroke (1.14, 0.65 to 2.00; P = 0.65), deep vein thrombosis (0.86, 0.53 to 1.39; P = 0.54), and pulmonary embolism (0.61, 0.25 to 1.47; P=0.27) was uncertain. Fewer deaths occurred in the tranexamic acid group (0.61, 0.38 to 0.98; P = 0.04), although when the analysis was restricted to trials using adequate concealment there was considerable uncertainty (0.67, 0.33 to 1.34; P = 0.25). Cumulative meta-analysis showed that reliable evidence that tranexamic acid reduces the need for transfusion has been available for over 10 years.

CONCLUSIONS

Strong evidence that tranexamic acid reduces blood transfusion in surgery has been available for many years. Further trials on the effect of tranexamic acid on blood transfusion are unlikely to add useful new information. However, the effect of tranexamic acid on thromboembolic events and mortality remains uncertain. Surgical patients should be made aware of this evidence so that they can make an informed choice.

Tranexamic acid reduces blood transfusions in elderly patients undergoing combined aortic valve and coronary artery bypass graft surgery: a randomized controlled trial

OBJECTIVE

To evaluate the effects of tranexamic acid on postoperative blood loss and transfusion requirements in elderly patients undergoing combined aortic valve replacement and coronary artery bypass graft surgery (CABG).

DESIGN

A prospective, randomized, double-blinded, placebo-controlled, parallel-group trial.

SETTING

A university hospital (single institution).

PARTICIPANTS

Sixty-four patients 70 years or older undergoing combined aortic valve replacement and CABG surgery were included. One patient was withdrawn from the study after randomization by the attending surgeon because of a change in the surgical procedure. The remaining 63 patients were analyzed as intention to treat.

INTERVENTIONS

The included patients were randomized to treatment with either tranexamic acid, 10 mg/kg, as a bolus injection before surgery followed by 1 mg/kg/h as an infusion during surgery, or a corresponding volume of 0.9% sodium chloride.

MEASUREMENTS AND MAIN RESULTS

Postoperative blood loss was recorded for 16 hours. The transfusion of blood products was recorded during the entire hospital stay. The number of packed red cell transfusions given to the patients was significantly lower in the tranexamic acid group compared with the placebo group (median, 3.0 [interquartile range, 2-5] v 5.0 [3-7], p = 0.049).

CONCLUSION

Tranexamic acid reduced the number of packed red cell transfusions given to patients 70 years or older undergoing combined aortic valve replacement and CABG surgery.

Diffuse alveolar hemorrhage

Diffuse alveolar hemorrhage (DAH) is a life-threatening disorder characterized clinically by the presence of hemoptysis, falling hematocrit, diffuse pulmonary infiltrates and hypoxemic respiratory failure. It refers to bleeding that originates in the pulmonary microvasculature instead of the parenchyma or bronchial circulation. DAH should be considered a medical emergency due to the morbidity and mortality associated with failure to treat the disorder promptly. Pulmonary renal syndromes, connective tissue disorders and drugs make up the majority of the cases of DAH. The treatment of DAH ranges from supportive care and withdrawal of offending drugs to high-dose steroids, immunosuppresents and plasmapharesis. The following review will discuss the clinical, radiographic and pathologic findings in a variety of disorders that cause DAH. Standard treatment options, as well as new treatment options will also be discussed.

Tranexamic acid reduces blood loss after off-pump coronary surgery: a prospective, randomized, double-blind, placebo-controlled study

BACKGROUND

Bleeding and the need for allogeneic transfusions are still problems after off-pump coronary artery bypass grafting (OPCAB) surgery. We therefore evaluated the effects of an antifibrinolytic, tranexamic acid, on postoperative bleeding and transfusion requirements in patients undergoing OPCAB surgery.

METHODS

Two hundred thirty-one consecutive patients scheduled for elective OPCAB were enrolled in the study. Using a double-blind method, the patients were randomly assigned to receive either tranexamic acid (bolus 1 g before surgical incision followed by an infusion of 400 mg/h during surgery; n = 116) or a placebo (infusion equivalent volume of saline solution; n = 115). The primary outcome was 24-hour postoperative chest tube drainage. Allogeneic transfusion, mortality, major morbidities, and resource utilization were also recorded.

RESULTS

In comparison with the placebo group, the patients receiving tranexamic acid had a significant reduction in chest tube drainage at 6 hours (270 ± 118 mL vs 416 ± 179 mL, P < 0.001) and 24 hours (654 ± 224 mL vs 891 ± 295 mL, P < 0.001). There was also a significant reduction in allogeneic red blood cell transfusions (47 vs 31.9%, P = 0.019) and fresh frozen plasma (29.6% vs 17.2%, P = 0.027) transfusions. There were no differences in mortality, morbidity, and resource utilization between the 2 groups.

CONCLUSIONS

Tranexamic acid reduces postoperative chest tube drainage and the requirement for allogeneic transfusion in off-pump coronary surgery.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. This version of the review includes a sensitivity analysis excluding trials authored by Prof. Joachim Boldt.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Tranexamic acid is associated with less blood transfusion in off-pump coronary artery bypass graft surgery: a systematic review and meta-analysis

OBJECTIVE

Tranexamic acid reduces blood loss and transfusion in on-pump coronary artery bypass graft (CABG) surgery. Compared with on-pump, off-pump surgery is associated with less blood loss and transfusion. Therefore, tranexamic acid may be less effective for off-pump surgery, and its safety profile may be different in this setting. The aim of this study was to determine the efficacy and safety of tranexamic acid for off-pump CABG surgery.

DESIGN

Systematic review and meta-analysis.

SETTING

University of Edinburgh.

INTERVENTIONS

The administration of tranexamic acid.

METHODS

A systematic review of randomized controlled trials administering tranexamic acid to patients undergoing off-pump CABG surgery. A meta-analysis of 24-hour blood loss, postoperative allogeneic transfusion, and thromboembolic events.

MEASUREMENTS AND MAIN RESULTS

Eight trials were identified. The lack of appropriate data limited the meta-analysis on blood loss. Tranexamic acid significantly reduced the overall risk of allogeneic blood component transfusion (risk ratio = 0.47; 95% confidence intervals, 0.33-0.66; p < 0.0001) and packed red blood cell transfusions (risk ratio = 0.51; 95% CI, 0.36-0.71; p = 0.0001). No association was found between tranexamic acid and myocardial infarction, stroke, or pulmonary embolism. Population sizes of meta-analyses ranged from 466 to 544.

CONCLUSIONS

Tranexamic acid reduces blood transfusion after off-pump surgery. Although no association with adverse events was found, the population sample size was too small to detect rare but clinically significant adverse events. A well-designed randomized controlled trial with an appropriate sample size is required to confirm tranexamic acid effectiveness and safety in off-pump CABG surgery.