Tranexamic acid and early saphenous vein graft patency in conventional coronary artery bypass graft surgery: a prospective randomized controlled clinical trial

The effect of tranexamic acid on myocardial injury in cardiac surgical patients: a systematic review and meta-analysis

Tranexamic acid (TXA) is one of the most commonly used antifibrinolytic agents for surgical patients. However, the effect of TXA on myocardial injury remains controversial. We systemically reviewed literature regarding the effectiveness of TXA on myocardial injury in patients who have undergone a cardiac surgery. We included all randomized controlled trials (RCTs) comparing TXA and control (saline) in cardiac surgical patients. Relevant studies were identified by a comprehensive electronic literature search from database inception to 15 August 2021. A standardized data extraction form was used to collect methodological and outcome variables from each eligible study. We conducted a meta-analysis to estimate the pooled effect size of TXA administration on myocardial injury. In total, eight RCTs were identified, with 292 patients in the TXA group, and 241 patients in saline or control group. The meta-analysis demonstrated that patients in the TXA group had lower levels of CK-MB and cTnI within 24 h postoperatively (CK-MB: P  = 0.005; cTnI: P  = 0.01), compared with the saline group. No significant difference was found with respect to AST level ( P  = 0.71) between TXA and saline groups within 24 h postoperatively. TXA administration was found to be associated with less myocardial injury among patients who have undergone cardiac surgery. High-quality randomized controlled trials are warranted to further examine the cardioprotective effects of TXA.

The role of tranexamic acid in breast and body contouring surgery: a review of the literature

Background: Postoperative seroma and haematoma are two of the most common complications follow-ing large surface area surgeries. A review of the literature was performed to evaluate evidence for the use of tranexamic acid in reducing postoperative seroma and haematoma formation in breast surgery and body contouring surgery. Methods A literature search was performed using MEDLINE, the Cochrane Database of Systematic Review, the Cochrane Central Register of Controlled Trials (CENTRAL), the Database of Abstracts of Reviews of Ef-fect (DARE) and PubMed in English from 1 Jan 1990–30 Mar 2020. The search terms ‘TXA’, ‘breast reduction’, ‘mammaplasty’, ‘breast implants’, ‘breast implantation’, ‘breast reconstruction’, ‘mastectomy’, ‘tissue ex-pansion’, ‘body contouring’, ‘breast’ and ‘abdominoplasty’ were used alone and in combination. Results: A total of six articles were found including three randomised controlled trials, two cohort studies and one retrospective study. Two ongoing trials were found on The Cochrane Central Register of Con-trolled Trials (CENTRAL). No systematic reviews were found. Conclusion: Literature surrounding the use of TXA in breast and body contouring surgery is sparse com-pared to what is available in other surgical sub-specialties. The literature available shows promising results with the use of TXA in controlling haematoma, drain output and seroma formation in breast surgery and body contouring surgery with minimal morbidity in these patient groups.

Association of Intravenous Tranexamic Acid With Thromboembolic Events and Mortality: A Systematic Review, Meta-analysis, and Meta-regression

IMPORTANCE

Tranexamic acid (TXA) is an efficient antifibrinolytic agent; however, concerns remain about the potential adverse effects, particularly vascular occlusive events, that may be associated with its use.

OBJECTIVE

To examine the association between intravenous TXA and total thromboembolic events (TEs) and mortality in patients of all ages and of any medical disciplines.

DATA SOURCE

Cochrane Central Register of Controlled Trials and MEDLINE were searched for eligible studies investigating intravenous TXA and postinterventional outcome published between 1976 and 2020.

STUDY SELECTION

Randomized clinical trials comparing intravenous TXA with placebo/no treatment. The electronic database search yielded a total of 782 studies, and 381 were considered for full-text review. Included studies were published in English, German, French, and Spanish. Studies with only oral or topical tranexamic administration were excluded.

DATA EXTRACTION AND SYNTHESIS

Meta-analysis, subgroup and sensitivity analysis, and meta-regression were performed. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

MAIN OUTCOMES AND MEASURES

Vascular occlusive events and mortality.

RESULTS

A total of 216 eligible trials including 125 550 patients were analyzed. Total TEs were found in 1020 (2.1%) in the group receiving TXA and 900 (2.0%) in the control group. This study found no association between TXA and risk for total TEs (risk difference = 0.001; 95% CI, -0.001 to 0.002; P = .49) for venous thrombosis, pulmonary embolism, venous TEs, myocardial infarction or ischemia, and cerebral infarction or ischemia. Sensitivity analysis using the risk ratio as an effect measure with (risk ratio = 1.02; 95% CI, 0.94-1.11; P = .56) and without (risk ratio = 1.03; 95% CI, 0.95-1.12; P = .52) studies with double-zero events revealed robust effect size estimates. Sensitivity analysis with studies judged at low risk for selection bias showed similar results. Administration of TXA was associated with a significant reduction in overall mortality and bleeding mortality but not with nonbleeding mortality. In addition, an increased risk for vascular occlusive events was not found in studies including patients with a history of thromboembolism. Comparison of studies with sample sizes of less than or equal to 99 (risk difference = 0.004; 95% CI, -0.006 to 0.014; P = .40), 100 to 999 (risk difference = 0.004; 95% CI, -0.003 to 0.011; P = .26), and greater than or equal to 1000 (risk difference = -0.001; 95% CI, -0.003 to 0.001; P = .44) showed no association between TXA and incidence of total TEs. Meta-regression of 143 intervention groups showed no association between TXA dosing and risk for venous TEs (risk difference, -0.005; 95% CI, -0.021 to 0.011; P = .53).

CONCLUSIONS AND RELEVANCE

Findings from this systematic review and meta-analysis of 216 studies suggested that intravenous TXA, irrespective of dosing, is not associated with increased risk of any TE. These results help clarify the incidence of adverse events associated with administration of intravenous TXA and suggest that TXA is safe for use with undetermined utility for patients receiving neurological care.

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.

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.

Tranexamic Acid Prophylaxis in Hip and Knee Joint Replacement

BACKGROUND

The antifibrinolytic agent tranexamic acid (TXA) is widely used for the prevention and treatment of hyperfibrinolytic states, such as in severe polytrauma. It can also be used for the systemic prevention of hemorrhage in elective orthopedic procedures. In this review, we assess the efficacy and risks of the prophylactic administration of tranexamic acid before major endoprosthetic surgery of the hip and knee.

METHODS

This review is based on pertinent articles retrieved by a selective literature search in the PubMed and Cochrane Library databases.

RESULTS

Endoprosthetic surgery of the hip and knee is often associated with perioperative blood losses exceeding 500 mL. The prophylactic administration of tranexamic acid immediately before such procedures has been shown in randomized, controlled trials to lessen the quantity of intra- and postoperative bleeding and to reduce the likelihood of blood transfusion (number needed to treat [NNT] 3.7-5.7 for knee replacement and 4.1-8.2 for hip replacement). The rate of thromboembolic events did not differ significantly from the rate in the placebo groups. No reliable data are available on the frequency of epileptic seizures as a complication of TXA use in knee and hip endoprosthetic surgery. On the basis of data from other types of surgery, one may reasonably conclude that the doses of TXA used for knee and hip endoprosthetic procedures are unlikely to cause this problem.

CONCLUSION

The prophylactic intravenous administration of tranexamic acid lessens the amount of bleeding in endoprosthetic knee and hip procedures and reduces the likelihood of blood transfusion. According to the current state of the evidence, complications are rare. Nonetheless, consideration of the risks and benefits implies that tranexamic acid should not be given for this purpose to patients who have recently had urogenital bleeding, pulmonary embolism, or a myocardial infarction, who have recently undergone percutaneous transluminal coronary angioplasty or stenting, or who are known to have epilepsy.

Tranexamic Acid-Encapsulating Thermosensitive Liposomes for Site-Specific Pharmaco-Laser Therapy of Port Wine Stains

Site-specific pharmaco-laser therapy (SSPLT) is a developmental stage treatment modality designed to non-invasively remove superficial vascular pathologies such as port wine stains (PWS) by combining conventional laser therapy with the prior administration of a prothrombotic and/or antifibrinolytic pharmaceutical-containing drug delivery system. For the antifibrinolytic SSPLT component, six different PEGylated thermosensitive liposomal formulations encapsulating tranexamic acid (TA), a potent antifibrinolytic lysine analogue, were characterized for drug:lipid ratio, encapsulation efficiency, size, endovesicular TA concentration (C TA), phase transition temperature (T m), and assayed for heat-induced TA release. Assays were developed for the quantification of liposomal TA and heat-induced TA release from two candidate formulations. The outcome parameters were then combined with a 3D histological reconstruction of a port wine stain biopsy to extrapolate in vivo posologies for SSPLT. The prime formulation, DPPC:DSPE-PEG2000 (96:4 molar ratio), had a drug:lipid molar ratio of 0.82, an encapsulation efficiency of 1.29%, a diameter of 155 nm, and a C TA of 214 mM. The peak TA release from this formulation (T m = 42.3 °C) comprised 96% within 2.5 min, whereas this was 94% in 2 min for DPPC:MPPC:DSPE-PEG2000 (86:10:4) liposomes (T m = 41.5 °C). Computational analysis revealed that < 400 DPPC:DSPE-PEG2000 (96:4 molar ratio) liposomes are needed to treat a PWS of 40 cm2, compared to a three-fold greater quantity of DPPC:MPPC:DSPE-PEG2000 (86:10:4) liposomes, indicating that, in light of the assayed parameters and endovascular laser-tissue interactions, the former formulation is most suitable for antifibrinolytic SSPLT. This was further confirmed with experiments involving ex vivo and in vivo liposome-platelet and liposome-red blood cell association as well as uptake and toxicity assays with cultured endothelial cells (HUVECs), macrophages (RAW 264.7), and hepatocytes (HepG2).

Association between CK-MB Area Under the Curve and Tranexamic Acid Utilization in Patients Undergoing Coronary Artery Bypass Surgery

Myonecrosis after coronary artery bypass graft (CABG) surgery is associated with excess mortality. Tranexamic acid (TA), an anti-fibrinolytic agent, has been shown to reduce peri-operative blood loss without increasing the risk of myocardial infarction (MI); however, no large study has examined the association between TA treatment and post-CABG myonecrosis. In the MC-1 to Eliminate Necrosis and Damage in Coronary Artery Bypass Graft Surgery II trial, inverse probability weighting of the propensity to receive TA was used to test for differences among the 656 patients receiving and 770 patients not receiving TA. The primary outcome was creatine kinase MB (CK-MB) area under the curve (AUC) through 24 h. The secondary outcome was 30-day cardiovascular death or MI. Patients who received TA were more frequently female, had a previous MI, heart failure, low molecular weight heparin therapy, on-pump CABG, valvular surgery, and saphenous vein or radial grafts. The median 24-h CK-MB AUC was higher in TA-treated patients [301.9 (IQR 196.7-495.6) vs 253.5 (153.4-432.5) ng h/mL, p < 0.001]. No differences in the 30-day incidence of cardiovascular death or MI were observed (8.7 vs 8.3%, adjusted OR 0.99; 95% CI 0.67-1.45, p = 0.948). In patients undergoing CABG, TA use was associated with a higher risk of myonecrosis; however, no differences were observed in death or MI. Future larger studies should be directed at examining the pathophysiology of TA myonecrosis, and its association with subsequent clinical outcomes.

Anti-hemorrhagic effect of prophylactic tranexamic acid in benign hysterectomy-a double-blinded randomized placebo-controlled trial

BACKGROUND

Hysterectomy is one of the most frequently performed major gynecological surgical procedures. Even when the indication for the procedure is benign, relatively high complication rates have been reported. Perioperative bleeding seems to represent the most common cause of complications and in 2004, 8% of all women in Denmark undergoing benign hysterectomy experienced a bleeding complication. Tranexamic acid is an antifibrinolytic agent that has shown to effectively reduce bleeding complications within other surgical and medical areas. However, knowledge about the drug's effect in relation to benign hysterectomy is still missing.

OBJECTIVE

To investigate the antihemorrhagic effect of prophylactic tranexamic acid in elective benign hysterectomy.

STUDY DESIGN

A double-blinded randomized placebo-controlled trial was conducted at 4 gynecological departments in Denmark from April 2013 to October 2014. A total of 332 women undergoing benign abdominal, laparoscopic, or vaginal hysterectomy were included in the trial, randomized to either 1 g of intravenous tranexamic acid or placebo at start of surgery. Chi-square test and Student t test statistical analyses were applied.

RESULTS

The primary outcome of intraoperative total blood loss was reduced in the group treated with tranexamic acid compared to the placebo group when estimated both subjectively by the surgeon and objectively by weight (98.4 mL vs 134.8 mL, P = .006 and 100.0 mL vs 166.0 mL, P = .004). The incidence of blood loss ≥500 mL was also significantly reduced (6 vs 21, P = .003), as well as the use of open-label tranexamic acid (7 vs 18, P = .024). Furthermore, the risk of reoperations owing to postoperative hemorrhage was significantly reduced in the tranexamic acid group compared to the placebo group (2 vs 9, P = .034). This corresponds to an absolute risk reduction of 4.2% and number needed to treat of 24. No incidence of thromboembolic events or death was observed in any of the groups.

CONCLUSION

The results support the hypothesis that prophylactic treatment with tranexamic acid reduces the overall total blood loss, the incidence of substantial blood loss, and the need for reoperations owing to postoperative hemorrhage in relation to benign hysterectomy. No incidences of serious adverse events occurred. Thus, tranexamic acid should be considered as a prophylactic treatment prior to elective benign hysterectomy.

Does Tranexamic Acid Reduce Blood Loss in Off-Pump Coronary Artery Bypass?

The hemostatic effect of tranexamic acid on the bleeding tendency and transfusion requirements in patients undergoing off-pump coronary artery bypass surgery was assessed in a prospective randomized double-blind study. Of 66 patients undergoing elective operations, 33 were given tranexamic acid (15 mg·kg−1 before infusion of heparin and 15 mg·kg−1 after protamine infusion), and the other 33 received only saline. Postoperative bleeding, transfusions, complications, hematological variables, and plasma D-dimer levels were recorded. Postoperative blood loss was significantly less in the tranexamic acid group compared to the control group (320 ± 38 vs 480 ± 75 mL). Patients in the tranexamic acid group received significantly less allogeneic blood products (0.46 vs 0.94 units per patient), and they had lower postoperative D-dimer levels. No postoperative thrombotic complications were observed in either group. Although off-pump coronary artery bypass surgery is associated with reduced frequency of hemorrhagic disorders, defective hemostasis still occurs, and tranexamic acid effectively reduces postoperative blood loss and the need for allogeneic blood products.

Topical tranexamic acid as a novel treatment for bleeding peptic ulcer: A randomised controlled trial

BACKGROUND

Peptic ulcers are among the most common causes of upper gastrointestinal (GI) bleeding in children. The standard care for GI bleeding is endoscopy for diagnostic and therapeutic purposes. We aimed to assess the effect of topical tranexamic acid (TXA) via endoscopic procedures in children with GI bleeding caused by bleeding ulcers.

PROCEDURE

In this randomised controlled trial, 120 children were evaluated by diagnostic procedures for GI bleeding, of which 63 (30 girls, 33 boys) aged 1-month to 15 years were recruited. The patients were randomly divided into case and control groups. In the case group, TXA was administered directly under endoscopic therapy. In the control group, epinephrine (1/10,000) was submucosally injected to the four quadrants of ulcer margins as the routine endoscopic therapy. In both groups, the patients received supportive medical therapy with intravenous fluids and proton pump inhibitor drugs.

RESULTS

The mean ± standard deviation age of the children was 5 ± 2.03 years. Rebleeding occurred in 15 (11.4%) and 21 (9.8%) patients in the case and control groups, respectively (P = 0.50). The frequency of blood transfusion episodes (P = 0.06) and duration of hospital stay (P = 0.07) were not statistically different between the groups.

CONCLUSION

Using topical TXA via endoscopic procedures may be effective in cases of GI bleedings caused by active bleeding ulcers. In order to establish this therapeutic effect, a large number of clinical studies are needed.

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.

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.

Tranexamic acid: a review of its use in the treatment of hyperfibrinolysis

Tranexamic acid, a synthetic derivative of the amino acid lysine, is an antifibrinolytic agent that acts by binding to plasminogen and blocking the interaction of plasmin(ogen) with fibrin, thereby preventing dissolution of the fibrin clot. Tranexamic acid (Transamin®) is indicated in Japan for use in certain conditions with abnormal bleeding or bleeding tendencies in which local or systemic hyperfibrinolysis is considered to be involved. This article reviews the efficacy and tolerability of tranexamic acid in conditions amenable to antifibrinolytic therapy and briefly overviews the pharmacological properties of the drug. In large, randomized controlled trials, tranexamic acid generally significantly reduced perioperative blood loss compared with placebo in a variety of surgical procedures, including cardiac surgery with or without cardiopulmonary bypass, total hip and knee replacement and prostatectomy. In many instances, tranexamic acid also reduced transfusion requirements associated with surgery. It also reduced blood loss in gynaecological bleeding disorders, such as heavy menstrual bleeding, postpartum haemorrhage and bleeding irregularities caused by contraceptive implants. Tranexamic acid significantly reduced all-cause mortality and death due to bleeding in trauma patients with significant bleeding, particularly when administered early after injury. It was also effective in traumatic hyphaema, gastrointestinal bleeding and hereditary angioneurotic oedema. While it reduces rebleeding in subarachnoid haemorrhage, it may increase ischaemic complications. Pharmacoeconomic analyses predicted that tranexamic acid use in surgery and trauma would be very cost effective and potentially life saving. In direct comparisons with other marketed agents, tranexamic acid was at least as effective as ε-aminocaproic acid and more effective than desmopressin in surgical procedures. It was more effective than desmopressin, etamsylate, flurbiprofen, mefenamic acid and norethisterone, but less effective than the levonorgestrel-releasing intra-uterine device in heavy menstrual bleeding and was as effective as prednisolone in traumatic hyphaema. Tranexamic acid was generally well tolerated. Most adverse events in clinical trials were of mild or moderate severity; severe or serious events were rare. Therefore, while high-quality published evidence is limited for some approved indications, tranexamic acid is an effective and well tolerated antifibrinolytic agent.

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.

Effect of tranexamic acid on transfusion requirement in dual antiplatelet-treated anemic patients undergoing off-pump coronary artery bypass graft surgery

BACKGROUND

Anemia is not rare in patients presenting for coronary artery bypass graft surgery (CABG) and as these patients are frequently on dual antiplatelet therapy (DAPT), the coexisting conditions could potentially increase the risk of bleeding and transfusion. The aim of this study was to evaluate the effect of tranexamic acid (TA) on blood loss and transfusion in preoperatively anemic patients who continued DAPT until within 5 days of off-pump CABG (OPCAB).

METHODS AND RESULTS

Seventy-six anemic patients were randomized into 2 groups: TA group receiving TA (1g bolus followed by infusion at 200mg/h) and a Control group receiving the same volume of saline. The amount of blood loss and transfusion requirement during, and at 4 and 24h after the operation were assessed. Patients' characteristics and operative data were similar between the groups. During the perioperative period, which combined the intraoperative and postoperative 24h data, the TA group received significantly smaller amounts of packed red blood cells and fresh frozen plasma. Total amount of perioperative blood loss was similar between the groups, although the blood loss during the postoperative 4h was significantly less in the TA group.

CONCLUSIONS

TA infusion could reduce the amount of transfusion during the perioperative period in patients with preoperative anemia who continue DAPT until within 5 days of OPCAB.

An overview of three promising mechanical, optical, and biochemical engineering approaches to improve selective photothermolysis of refractory port wine stains

During the last three decades, several laser systems, ancillary technologies, and treatment modalities have been developed for the treatment of port wine stains (PWSs). However, approximately half of the PWS patient population responds suboptimally to laser treatment. Consequently, novel treatment modalities and therapeutic techniques/strategies are required to improve PWS treatment efficacy. This overview therefore focuses on three distinct experimental approaches for the optimization of PWS laser treatment. The approaches are addressed from the perspective of mechanical engineering (the use of local hypobaric pressure to induce vasodilation in the laser-irradiated dermal microcirculation), optical engineering (laser-speckle imaging of post-treatment flow in laser-treated PWS skin), and biochemical engineering (light- and heat-activatable liposomal drug delivery systems to enhance the extent of post-irradiation vascular occlusion).

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.

Lessons from aprotinin: is the routine use and inconsistent dosing of tranexamic acid prudent? Meta-analysis of randomised and large matched observational studies

In view of the safety concerns that led to the withdrawal of aprotinin, should antifibrinolytics be used indiscriminately in cardiac surgery? This meta-analysis examines the efficacy and safety profile of tranexamic acid, and in comparison to aprotinin. We identified randomised trials and large observational studies investigating the use tranexamic acid from January 1995 to January 2009 using Pubmed/Cochrane search engine and included them in a two-tier meta-analysis. There were 25 randomised trials and four matched studies with a total of 5411 and 5977 patients, respectively, reporting tranexamic acid use in varying dosages. Tranexamic acid is administered intravenously either as single dose, infusion or both, sometimes added to pump prime or applied topically. Total intravenous dose of tranexamic acid varies from 1g to 20 g, administered over a period of 20 min to 12h. Compared with placebo, tranexamic acid is associated with a lower mean difference in blood loss (random effect -298 ml, 95% confidence [CI] -367 to -229, p<0.001) and decease in rates of re-operation for bleeding by 48%, transfusion of packed red cell by 47% and use of haemostatic blood products by 67%. A non-significant tendency for postoperative neurological events but a decrease in operative mortality was observed in patients treated with tranexamic acid compared with non-treatment group. Compared to aprotinin, tranexamic acid has less effective blood-conserving effect and mortality risk. Given the potential to increase neurological complications, the current trend towards indiscriminate use of tranexamic acid for all cardiac patients needs to be re-evaluated. Further studies are needed to clarify the neurological risk, appropriate indications and dosing of tranexamic acid.

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

OBJECTIVE

This study was designed to evaluate the hemostatic effect of tranexamic acid in off-pump coronary artery bypass surgery.

DESIGN

A prospective, randomized, double-blind, placebo-controlled study.

SETTING

The Department of Anesthesiology and Cardiac Surgery, Medical Sciences University.

PARTICIPANTS

One hundred eight patients undergoing off-pump coronary artery bypass surgery were enrolled into the study. Eight patients were withdrawn, and 100 patients were divided into 2 groups.

INTERVENTIONS

Fifty patients received tranexamic acid (bolus 1 g before skin incision and followed by maintenance dose of 400 mg/h during surgery), and 50 patients received saline.

MEASUREMENT AND MAIN RESULTS

Hematologic parameters, volume of blood loss, blood transfusion, and other clinical data were recorded throughout the perioperative period. Twenty-four-hour postoperative blood loss was significantly less in the tranexamic acid group compared with the control group (471 +/- 182 v 844 +/- 303). Patients in the tranexamic acid group received significantly less allogeneic blood (8 v 31 units).

CONCLUSION

Bleeding and hemorrhagic complications and the consequent need for allogeneic transfusion are still major problems after off-pump coronary artery bypass surgery. Tranexamic acid appears to be effective in reducing postoperative bleeding and the need for allogeneic blood products.

A benefit-risk review of systemic haemostatic agents: part 1: in major surgery

Systemic haemostatic agents play an important role in the management of blood loss during major surgery where significant blood loss is likely and their use has increased in recent times as a consequence of demand for blood products outstripping supply and the risks associated with transfusions. Their main application is as prophylaxis to reduce bleeding in major surgery, including cardiac and orthopaedic surgery and orthotopic liver transplantation. Aprotinin has been the predominant agent used in this setting; of the other antifibrinolytic agents that have been studied, tranexamic acid is the most effective and epsilon-aminocaproic acid may also have a role. Eptacog alfa (recombinant factor VIIa) has also shown promise. Tranexamic acid, epsilon-aminocaproic acid and eptacog alfa are generally well tolerated; however, when considering the methods to reduce or prevent blood loss intra- and postoperatively, the benefits of these agents need to be weighed against the risk of adverse events. Recently, concerns have been raised about the safety of aprotinin after an association between increased renal dysfunction and mortality was shown in retrospective observational studies and an increase in all-cause mortality with aprotinin relative to tranexamic acid or epsilon-aminocaproic acid was seen after a pre-planned periodic analysis of the large BART (Blood conservation using Antifibrinolytics in a Randomized Trial) study. The latter finding resulted in the trial being halted, and aprotinin has subsequently been withdrawn from the market pending detailed analysis of efficacy and safety results from the study. Part 1 of this benefit-risk review examines the efficacy and adverse effect profiles of systemic haemostatic agents commonly used in surgery, and provides individual benefit-risk profiles that may assist clinicians in selecting appropriate pharmacological therapy in this setting.

Effects of tranexamic acid and autotransfusion in coronary artery bypass

The aim of this study was to compare the effects of intraoperative autotransfusion and tranexamic acid on postoperative bleeding and the need for allogeneic transfusion. In a prospective randomized study, 200 patients undergoing coronary artery bypass were divided into two groups: 100 patients received 1-2 units of autologous blood after termination of cardiopulmonary bypass; and 100 patients were given tranexamic acid 15 mg x kg(-1) before injection of heparin and again before injection of protamine. Postoperative bleeding was significantly lower in the tranexamic acid group (600 mL) than the autotransfusion group (1,100 mL). The percentage of patients transfused in the autotransfusion and tranexamic acid groups was 70% and 65%, respectively. Patients in the autotransfusion group received significantly more whole blood (2.82 vs 1.93 units). Intensive care and hospital stays were shorter in the tranexamic acid group. There was no hospital mortality and no difference in thrombotic complications between groups. Tranexamic acid was more effective than autotransfusion in reducing postoperative blood loss and allogeneic transfusions after coronary bypass.

Prevalence of claustrophobia and magnetic resonance imaging after coronary artery bypass graft surgery

BACKGROUND

The purpose of this study was to determine the prevalence of claustrophobia in patients undergoing magnetic resonance imaging (MRI) after coronary artery bypass graft (CABG) surgery.

METHODS

After IRB approval, we conducted a substudy of a prospective randomized controlled clinical trial of 311 patients evaluating administration of tranexamic acid and early saphenous vein graft patency with MRI after conventional CABG surgery. Chest tube drainage was measured at 6, 12, and 24 hours after surgery. The rate of transfusion and the amount of red blood cells (RBC), fresh frozen plasma (FFP), and platelets transfused were recorded.

RESULTS

A total of 237(76%) patients underwent MRI after surgery. 39 (14%, [95% CI, 10.2 to 18.0]) patients experienced severe anxiety caused by a fear of enclosed space in the MRI coil necessitating termination of the procedure. Patients with claustrophobia were on average 5 years younger. They were more likely to have diabetes mellitus and hypertension. Patients with claustrophobia had increased chest tube drainage during the postoperative period. The rate of blood product transfusion was similar between the two groups but patients with claustrophobia who were transfused received significantly more RBC and FFP than patients without claustrophobia.

CONCLUSIONS

Postoperative claustrophobia and anxiety, leading to inability to undergo MRI, may be more common than previously described.

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 and the need for transfusion. Recently, questions have been raised regarding the comparative performance of the drugs and the safety of the most popular agent, aprotinin.

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 (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, and the internet. 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 2006.

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 211 RCTs that recruited 20,781 participants. Data from placebo/inactive controlled trials, and from head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of operative blood loss, but the differences were small. Aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.61 to 0.71). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.54 to 0.69) and it was 0.75 (95% CI 0.58 to 0.96) 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 superior in reducing the need for RBC transfusion: RR 0.83 (95% CI 0.69 to 0.99). Aprotinin reduced the need for re-operation due to bleeding: RR 0.48 (95% CI 0.35 to 0.68). This translates into an absolute risk reduction of just under 3% and a number needed-to-treat (NNT) of 37 (95% CI 27 to 56). Similar trends were seen with TXA and EACA, but the data were sparse and the differences failed to reach statistical significance. The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias. Evidence of publication bias was not observed in trials reporting re-operation rates. Adjustment for these effects reduced the magnitude of estimated benefits but did not negate treatment effects. However, the apparent advantage of aprotinin over the lysine analogues was small and may be explained by publication bias and non-equivalent drug doses. Aprotinin did not increase the risk of myocardial infarction (RR 0.92, 95% CI 0.72 to 1.18), stroke (RR 0.76, 95% CI 0.35 to 1.64) renal dysfunction (RR 1.16, 95% CI 0.79 to 1.70) or overall mortality (RR 0.90, 95% CI 0.67 to 1.20). The analyses of myocardial infarction and death included data from the majority of subjects recruited into the clinical trials of aprotinin. However, under-reporting of renal events could explain the lack of effect seen with aprotinin. Similar trends were seen with the lysine analogues but data were sparse. These results conflict with the results of recently published non-randomised studies.

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the need for allogeneic red cell transfusion. Based on the results of randomised trials their efficacy does not appear to be offset by serious adverse effects. In most circumstances the lysine analogues are probably as effective as aprotinin and are cheaper; the evidence is stronger for tranexamic acid than for aminocaproic acid. In high risk cardiac surgery, where there is a substantial probability of serious blood loss, aprotinin may be preferred over tranexamic acid. Aprotinin does not appear to be associated with an increased risk of vascular occlusion and death, but the data do not exclude an increased risk of renal failure. There is no need for further placebo-controlled trials of aprotinin or lysine analogues in cardiac surgery. The principal need is for large comparative trials to assess the relative efficacy, safety and cost-effectiveness of anti-fibrinolytic drugs in different surgical procedures.

Tranexamic acid reduces postoperative bleeding in off-pump coronary artery bypass grafting

OBJECTIVE

Tranexamic acid (TA) reduces blood loss in coronary artery surgery with cardiopulmonary bypass. The present prospective study was designed to investigate its hemostatic effect in off-pump coronary artery bypass (OPCAB).

METHOD

Seventy-six patients undergoing elective OPCAB were randomized into two groups, received TA (0.75 g loading dose before surgery and 250 mg/h during surgery, gross dose: 1.5 g, n=36) and saline solution (control, n=40), respectively. Perioperative blood samples were collected. Hematochemical parameters including platelet adhesion rate, D-dimer and fibrinopeptide-A (FPA) were analysis. Volume of blood loss, blood transfusion and other clinical data were recorded throughout the perioperative period.

RESULTS

Cumulative blood loss was significantly reduced in the TA group as compared to the controls postoperatively (6 hrs (median [25th-75th]): TA: 200.0 [140.0-230.0] ml,

CONTROL

225.0 [200.0-347.5.0] ml, p=0.009; 24 hrs: TA: 440.0 [270.0-605.0] ml,

CONTROL

655.0 [500.0-920.0] ml, p<0.001). Number of patients received blood transfusion in each group was similar. Levels of D-dimer rose significantly after surgery, and were significantly lower in the TA group than that in controls. Platelet adhesion rate and FPA levels remained at baseline levels after the operation in two groups. Early clinical outcomes were similar between groups.

CONCLUSION

The results indicated that tranexamic acid limits fibrinolysis and reduces blood loss after off-pump coronary artery bypass surgery.

Meta-analysis comparing the effectiveness and adverse outcomes of antifibrinolytic agents in cardiac surgery

BACKGROUND

Since the 1980s, antifibrinolytic therapies have assisted surgical teams in reducing the amount of blood loss. To date, however, serious questions remain regarding the safety and effectiveness of these agents.

METHODS AND RESULTS

We conducted a meta-analysis to compare aprotinin, epsilon-aminocaproic acid, and tranexamic acid with placebo and head to head on 8 clinical outcomes from 138 trials. Published randomized controlled trial data were collected from OVID/PubMed. Outcomes included total blood loss, transfusion of packed red blood cells, reexploration, mortality, stroke, myocardial infarction, dialysis-dependent renal failure, and renal dysfunction (0.5-mg/dL increase in creatinine from baseline). All agents were effective in significantly reducing blood loss by 226 to 348 mL and the proportion of patients transfused with packed red blood cells over placebo. Only high-dose aprotinin reduced the rate of reexploration (relative risk, 0.49; 95% CI, 0.33 to 0.73). There were no significant risks or benefits for any agent for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin significantly increased the risk of renal dysfunction (relative risk, 1.47; 95% CI, 1.12 to 1.94), 12.9% versus 8.4%. Compared head to head, high-dose aprotinin demonstrated significant reduction in total blood loss over epsilon-aminocaproic acid (-184 mL; 95% CI, -256 to -112) and tranexamic acid (-195 mL; 95% CI, -286 to -105). There were no significant differences among any agent when compared head to head on other outcomes.

CONCLUSIONS

All antifibrinolytic agents were effective in reducing blood loss and transfusion. There were no significant risks or benefits for mortality, stroke, myocardial infarction, or renal failure. However, high-dose aprotinin was associated with a statistically significant increased risk of renal dysfunction.