Effect of epsilon aminocaproic acid on red-cell transfusion requirements in major spinal surgery

Comparative efficacy and safety of different hemostatic medications during spinal surgery: A network meta-analysis

BACKGROUND

Significant blood loss is still one of the most frequent issues in spinal surgery. There were different hemostatic methods to prevent blood loss during spinal surgery. However, the optimal hemostatic therapy for spinal surgery is controversial. The purpose of this study was to assess the efficacy and safety of different hemostatic therapies in spinal surgery.

METHODS

Two independent reviewers conducted electronic literature searches in 3 electronic databases (PubMed, Embase, and Cochrane library database) as well as a manual search to identify eligible clinical studies from inception to Nov 2022. Studies that including different hemostatic therapy (tranexamic acid [TXA], epsilon-acetyl aminocaproic acid [EACA], and aprotinin [AP]) for spinal surgery were included. The Bayesian network meta-analysis was performed with a random effects model. The surface under the cumulative ranking curve (SUCRA) analysis was performed to determine the ranking order. All analyses were performed by R software and Stata software. P value less than .05 was identified as statistically significant.

RESULTS

Finally, a total of 34 randomized controlled trials met the inclusion criteria and finally included in this network meta-analysis. The SUCRA shows that TXA ranked first (SUCRA, 88.4%), AP ranked second (SUCRA, 71.6%), EACA ranked third (SUCRA, 39.9%), and placebo ranked the last (SUCRA, 0.3%) as for total blood loss. The SUCRA shows that TXA ranked first (SUCRA, 97.7%), AP ranked second (SUCRA, 55.8%), EACA ranked third (SUCRA, 46.2%), and placebo ranked the last (SUCRA, 0.2%) for need for transfusion.

CONCLUSIONS

TXA appears optimal in the reduction of perioperative bleeding and blood transfusion during spinal surgery. However, considering the limitations in this study, more large-scale, well-designed randomized controlled trials are needed to confirm these findings.

Randomized, controlled trial of two tranexamic acid dosing protocols in adult spinal deformity surgery

BACKGROUND

Tranexamic acid (TXA) is an anti-fibrinolytic effective in reducing blood loss in orthopedic surgery. The appropriate dosing protocol for adult spinal deformity (ASD) surgery is not known. The purpose of this study was to evaluate two TXA protocols [low dose (L): 10 mg/kg bolus, 1 mg/kg/hr infusion; high dose (H): 50 mg/kg, 5 mg/kg/hr] in complex ASD surgery.

METHODS

Inclusion criteria were ASD reconstructions with minimum 10 fusion levels or planned 3-column osteotomy (3CO). Standard demographic and surgical data were collected. Intraoperative estimated blood loss (EBL) was calculated by suction canisters minus irrigation plus estimated blood lost in sponges, estimated to the nearest 50 mL. Serious adverse events (SAE) were defined a priori as: venothromboembolic event (VTE), cardiac arrhythmia, myocardial infarction, renal dysfunction, and seizure. All SAE were recorded. Simple t tests compared EBL between groups. Mean EBL by total blood volume (TBV), transfusion volume, complications related to TXA were secondary outcomes.

RESULTS

Sixty-two patients were enrolled and 52 patients completed the study; 25 were randomized to H and 27 to L. Demographic and surgical variables were not different between the two groups. EBL was not different between groups (H: 1596 ± 933 cc, L: 2046 ± 1105 cc, p = 0.12, 95% CI: - 1022 to 122 cc). EBL as a percentage of TBV was lower for the high-dose group (H: 29.5 ± 14.8%, L: 42.5 ± 26.2%, p = 0.03). Intraoperative transfusion volume (H: 961 ± 505 cc, L: 1105 ± 808 cc, p = 0.5) and post-operative transfusion volume (H: 513 ± 305 cc, L: 524 ± 245 cc, p = 0.9) were not different. SAE related to TXA were not different (p = 0.7) and occurred in 2 (8%) H and 3 (11%) L. There was one seizure (H), 2 VTE, and 2 arrhythmias.

CONCLUSION

No differences in EBL, transfusion volume, nor SAE were observed between H and L dose TXA protocols. High dose was associated with decreased TBV loss (13%). Further prospective study, with pharmacologic analysis, is required to determine appropriate TXA dosage in ASD surgeries.

LEVEL OF EVIDENCE

Therapeutic Level II.

TRIAL REGISTRATION

The study was registered at Clinicaltrials.gov (NCT02053363) February 3, 2014.

Hemostats in Spine Surgery: Literature Review and Expert Panel Recommendations

Bleeding in spine surgery is a common occurrence but when bleeding is uncontrolled the consequences can be severe due to the potential for spinal cord compression and damage to the central nervous system. There are many factors that influence bleeding during spine surgery including patient factors and those related to the type of surgery and the surgical approach to bleeding. There are a range of methods that can be employed to both reduce the risk of bleeding and achieve hemostasis, one of which is the adjunct use of hemostatic agents. Hemostatic agents are available in a variety of forms and materials and with considerable variation in cost, but specific evidence to support their use in spine surgery is sparse. A literature review was conducted to identify the pre-, peri-, and postsurgical considerations around bleeding in spine surgery. The review generated a set of recommendations that were discussed and ratified by a wider expert group of spine surgeons. The results are intended to provide a practical guide to the selection of hemostats for specific bleeding situations that may be encountered in spine surgery.

Perioperative Care of Patients Undergoing Major Complex Spinal Instrumentation Surgery: Clinical Practice Guidelines From the Society for Neuroscience in Anesthesiology and Critical Care

Evidence-based standardization of the perioperative management of patients undergoing complex spine surgery can improve outcomes such as enhanced patient satisfaction, reduced intensive care and hospital length of stay, and reduced costs. The Society for Neuroscience in Anesthesiology and Critical Care (SNACC) tasked an expert group to review existing evidence and generate recommendations for the perioperative management of patients undergoing complex spine surgery, defined as surgery on 2 or more thoracic and/or lumbar spine levels. Institutional clinical management protocols can be constructed based on the elements included in these clinical practice guidelines, and the evidence presented.

The Efficacy and Safety of Epsilon-Aminocaproic Acid for Perioperative Blood Management in Spinal Fusion Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Perioperative blood loss is a major concern in spinal fusion surgery and often requires blood transfusion. A large amount of perioperative blood loss might increase the risks of various perioperative complications. Recent clinical studies have focused on the perioperative administration of epsilon-aminocaproic acid (EACA) in spinal fusion surgery. The aim of this review was to evaluate the efficacy and safety of EACA in spinal fusion surgery.

METHODS

Electronic databases (MEDLINE, EMBASE, PubMed, and Cochrane Central Register of Controlled Trials) were systematically searched up to April 2021. Data on perioperative blood loss, blood transfusion, and complications were extracted and analyzed by RevMan software.

RESULTS

Six randomized controlled studies comprising 398 patients undergoing spinal fusion surgery were included in this systematic review. Compared with the control group, the EACA group had significantly lower total perioperative blood loss, postoperative blood loss, postoperative hemoglobin, postoperative blood transfusion units, total blood transfusion units, and postoperative red blood cell transfusion units. Additionally, no significant differences were observed between the EACA and control groups in intraoperative blood loss, intraoperative blood transfusion units, intraoperative crystalloid administered, hospital stays, operative time, perioperative respiratory complications, and wound bleeding.

CONCLUSIONS

EACA in patients undergoing spinal fusion surgery is effective in perioperative hemostasis without increasing the incidence of postoperative complications. However, more large-scale trials are needed to examine the long-term adverse side effects of EACA in spinal fusion surgery.

Minimizing Blood Loss in Spine Surgery

STUDY DESIGN

Broad narrative review.

OBJECTIVE

To review and summarize the current literature on guidelines, outcomes, techniques and indications surrounding multiple modalities of minimizing blood loss in spine surgery.

METHODS

A thorough review of peer-reviewed literature was performed on the guidelines, outcomes, techniques, and indications for multiple modalities of minimizing blood loss in spine surgery.

RESULTS

There is a large body of literature that provides a consensus on guidelines regarding the appropriate timing of discontinuation of anticoagulation, aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and herbal supplements prior to surgery. Additionally, there is a more heterogenous discussion the utility of preoperative autologous blood donation facilitated by erythropoietin and iron supplementation for healthy patients slated for procedures with high anticipated blood loss and for whom allogeneic transfusion is likely. Intraoperative maneuvers available to minimize blood loss include positioning and maintaining normothermia. Tranexamic acid (TXA), bipolar sealer electrocautery, and topical hemostatic agents, and hypotensive anesthesia (mean arterial pressure (MAP) <65 mm Hg) should be strongly considered in cases with larger exposures and higher anticipated blood loss. There is strong level 1 evidence for the use of TXA in spine surgery as it reduces the overall blood loss and transfusion requirements.

CONCLUSION

As the volume and complexity of spinal procedures rise, intraoperative blood loss management has become a pivotal topic of research within the field. There are many tools for minimizing blood loss in patients undergoing spine surgery. The current literature supports combining techniques to use a cost- effective multimodal approach to minimize blood loss in the perioperative period.

Efficacy and safety of antifibrinolytic agents in spinal surgery: a network meta-analysis

Background:

Significant blood loss is still one of the most frequent complications in spinal surgery, which often necessitates blood transfusion. Massive perioperative blood loss and blood transfusion can create additional risks. Aprotinin, tranexamic acid (TXA), and epsilon-aminocaproic acid (EACA) are antifibrinolytics currently offered as prophylactic agents to reduce surgery-associated blood loss. The aim of this study was to evaluate the efficacy and safety of aprotinin, EACA, and low/high doses of TXA in spinal surgery, and assess the use of which agent is the most optimal intervention using the network meta-analysis (NMA) method.

Methods:

Five electronic databases were searched, including PubMed, Cochrane Library, ScienceDirect, Embase, and Web of Science, from the inception to March 1, 2018. Trials that were randomized and compared results between TXA, EACA, and placebo were identified. The NMA was conducted with software R 3.3.2 and STATA 14.0.

Results:

Thirty randomized controlled trial (RCT) studies were analyzed. Aprotinin (standardized mean difference [SMD]=−0.65, 95% credibility intervals [CrI;−1.25, −0.06]), low-dose TXA (SMD = −0.58, 95% CrI [−0.92, −0.25]), and high-dose TXA (SMD = −0.70, 95% CrI [−1.04, −0.36]) were more effective than the respective placebos in reducing intraoperative blood loss. Low-dose TXA (SMD = −1.90, 95% CrI [−3.32, −0.48]) and high-dose TXA (SMD = −2.31, 95% CrI [−3.75, −0.87]) had less postoperative blood loss. Low-dose TXA (SMD = −1.07, 95% CrI [−1.82, −0.31]) and high-dose TXA (SMD = −1.07, 95% CrI [−1.82, −0.31]) significantly reduced total blood loss. However, only high-dose TXA (SMD = −2.07, 95% CrI [−3.26, −0.87]) was more effective in reducing the amount of transfusion, and was significantly superior to low-dose TXA in this regard (SMD = −1.67, 95% CrI [−3.20, −0.13]). Furthermore, aprotinin (odds ratio [OR] = 0.16, 95% CrI [0.05, 0.54]), EACA (OR = 0.46, 95% CrI [0.22, 0.97]) and high dose of TXA (OR = 0.34, 95% CrI [0.19, 0.58]) had a significant reduction in transfusion rates. Antifibrinolytics did not show a significantly increased risk of postoperative thrombosis. Results of ranking probabilities indicated that high-dose TXA had the greatest efficacy and a relatively high safety level.

Conclusions:

The antifibrinolytic agents are able to reduce perioperative blood loss and transfusion requirement during spine surgery. And the high-dose TXA administration might be used as the optimal treatment to reduce blood loss and transfusion.

The Efficacy and Safety of Epsilon-Aminocaproic Acid for Blood Loss and Transfusions in Spinal Deformity Surgery: A Meta-Analysis

OBJECTIVE

To assess the efficacy and safety of epsilon-aminocaproic acid (EACA) in reducing the blood loss and transfusion volume during open spinal deformity surgery.

METHODS

A systematic search was conducted for all studies written in English published on or before October 2018 in PubMed, EMBASE, and the Cochrane Library that compared antifibrinolytic agents with placebos for open spinal deformity surgeries. The primary outcomes included the total blood loss, intraoperative, and postoperative blood loss, transfusions volume and complication rate.

RESULTS

Seven studies that included 525 patients who were diagnosed with spinal deformity. Compared with placebo, the patients who received EACA showed a reduction in the postoperative blood loss (mean difference [MD] -249.80; 95% confidence interval [CI] -375.65 to -123.95; P = 0.0001) and total blood loss (MD -670.30; 95% CI -1142.63 to -197.98; P = 0.005). Furthermore, the patients treated with EACA received approximately 1.67 fewer units of blood (MD -1.67; 95% CI -3.10 to -0.24; P = 0.02). However, in this cohort, no statistically significant differences were observed in the intraoperative blood loss (MD -452.19; 95% CI -1082.21 to 177.83; P = 0.16) and complication rate (odds ratio 0.73; 95% CI 0.16-3.24; P = 0.68).

CONCLUSIONS

This meta-analysis demonstrated that EACA could be safe and potentially efficacious for reducing blood loss and transfusions volume in patients with spinal deformity surgeries when compared with placebo. In light of the significant heterogeneity, the findings of this meta-analysis should be confirmed in methodologically rigorous and adequately powered clinical trials.

Determinants of perioperative transfusion risk in patients with adult spinal deformity

OBJECTIVE

To determine predictors of perioperative allogeneic packed red blood cell (pRBC) transfusion requirement (total units transfused) in patients with adult spinal deformity (ASD).

METHODS

The authors retrospectively analyzed records of patients aged 18 years or older who underwent surgical correction of ASD that involved 4 or more spinal levels by the same spine surgeon between 2010 and 2016. Data regarding patient characteristics, comorbidities, surgical factors, and perioperative transfusions (up to 10 days after surgery) were analyzed using a linear regression model. Significance was set at p < 0.05.

RESULTS

The authors analyzed 165 patients (118 women) with a mean (± SD) age of 61 ± 12 years. Three-column osteotomies were associated with a mean intraoperative transfusion volume of 1.74 additional units of pRBCs. Each unit of intraoperatively salvaged blood used was associated with a mean 0.39-U increase in postoperative transfusion volume (p = 0.031). Every unit of allogeneic blood transfused intraoperatively was associated with a mean 0.23-U decrease in postoperative transfusion volume (p = 0.001). A preoperative hemoglobin concentration of 11.5 g/dl or more was associated with significantly fewer units transfused intraoperatively; a preoperative hemoglobin concentration of 14.0 g/dl or more was associated with fewer units transfused postoperatively. A history of smoking and intraoperative antifibrinolytic use were associated with increased and decreased numbers of units transfused postoperatively, respectively.

CONCLUSIONS

Effective blood management is key to perioperative care of patients with ASD. Three-column osteotomies were associated with a greater number of units of blood transfused. When considering postoperative transfusion requirements, surgeons should note that intraoperative blood salvage might be inferior to intraoperative allogeneic blood transfusion. Using antifibrinolytics and increasing the preoperative hemoglobin concentration to 11.5 g/dl or more are strategies for decreasing the need for perioperative transfusion. A history of smoking is a risk factor for postoperative transfusion requirement (total units transfused).

Spine Surgery and Blood Loss: Systematic Review of Clinical Evidence

Spine surgery has been growing rapidly as a neurosurgical operation, with an increase of 220% over a 15-year period. Intraoperative blood transfusion is a major outcome determinant of spine procedures. Various approaches, including pharmacologic and nonpharmacologic therapies, have been tested to decrease both intraoperative and postoperative blood loss. The aim of this systematic review is to report clinical evidence on the relationship between intraoperative blood loss (primary outcome) and on transfusion requirements and postoperative complications (secondary outcomes) in patients undergoing spine surgery. A literature search of PubMed database was performed using 5 key words: spine surgery and transfusion; spine surgery and blood loss; spine surgery and blood complications; spine surgery and deep vein thrombosis; and spine surgery and pulmonary embolism. Clinical reports (randomized controlled trials, prospective and retrospective studies, and case reports) were selected. A total of 473 articles were examined; 450 were excluded, and 24 were selected for this systematic review. Selected articles were categorized into 3 subchapters: (1) drugs active on coagulation (12 studies): tranexamic acid, aminocaproic acid, aprotinin, and recombinant activated factor VII; (2) drugs not active on coagulation (5 studies): ketorolac, epoetin alfa, magnesium sulfate, propofol/sevoflurane, and omega-3 and fish oil; (3) nonpharmacologic approaches (7 studies): surgical tips, patient positioning, and general or spinal anesthesia. Several studies have shown a significant reduction in intraoperative bleeding during spine surgery and in the requirement for blood transfusion.

Efficacy of tranexamic acid on surgical bleeding in spine surgery: a meta-analysis

BACKGROUND CONTEXT

Spine surgery is usually associated with large amount of blood loss, necessitating blood transfusions. Blood loss-associated morbidity can be because of direct risks, such as hypotension and organ damage, or as a result of blood transfusions. The antifibrinolytic, tranexamic acid (TXA), is a lysine analog that inhibits activation of plasminogen and has shown to be beneficial in reducing surgical blood loss.

PURPOSE

To consolidate the findings of randomized controlled trials (RCTs) investigating the use of TXA on surgical bleeding in spine surgery.

STUDY DESIGN

A metaanalysis.

STUDY SAMPLE

Randomized controlled trials investigating the effectiveness of intravenous TXA in reducing blood loss in spine surgery, compared with a placebo/no treatment group.

METHODS

MEDLINE, Embase, Cochrane controlled trials register, and Google Scholar were used to identify RCTs published before January 2014 that examined the effectiveness of intravenous TXA on reduction of blood loss and blood transfusions, compared with a placebo/no treatment group in spine surgery. Metaanalysis was performed using RevMan 5. Weighted mean difference with 95% confidence intervals was used to summarize the findings across the trials for continuous outcomes. Dichotomous data were expressed as risk ratios with 95% confidence intervals. A p<.05 was considered statistically significant.

RESULTS

Eleven RCTs were included for TXA (644 total patients). Tranexamic acid reduced intraoperative, postoperative, and total blood loss by an average of 219 mL ([-322, -116], p<.05), 119 mL ([-141, -98], p<.05), and 202 mL ([-299, -105], p<.05), respectively. Tranexamic acid led to a reduction in proportion of patients who received a blood transfusion (risk ratio 0.67 [0.54, 0.83], p<.05) relative to placebo. There was one myocardial infarction (MI) in the TXA group and one deep vein thrombosis (DVT) in placebo.

CONCLUSIONS

Tranexamic acid reduces surgical bleeding and transfusion requirements in patients undergoing spine surgery. Tranexamic acid does not appear to be associated with an increased incidence of pulmonary embolism, DVT, or MI.

Efficacy and safety of using antifibrinolytic agents in spine surgery: a meta-analysis

PURPOSE

Spine surgery, particularly reconstructive surgery, can be associated with significant blood loss, and blood transfusion. Antifibrinolytic agents are used routinely to reduce bleeding in cardiac, orthopaedic, and hepatic surgery. The purpose of this study was to assess the efficacy and safety of using antifibrinolytic agents in reducing blood loss and blood transfusions in spine surgery.

METHODS

A systematic search of all related studies written in English published by October 2012 was conducted using the MEDLINE, EMBASE and the Cochrane Library databases. Randomized controlled trials that reported the drug dosage, total blood loss, blood transfusion and incidence of deep vein thrombosis as the primary outcome were included.

RESULTS

Nine studies involving 482 patients were identified. Patients receiving antifibrinolytic agents had reduced blood loss (WMD =-288.8, 95 % CI - 46.49, - 110.19; P = 0.002), reduced blood transfusion (WMD =-242.7, 95 % CI - 422.57, - 62.95; P = 0.008), reduced blood transfusion rate (RR 0.73, 95% CI 0.58, 0.93; p = 0.010) and no increase (RR 0.25, 95 % CI 0.03, 2.22; P = 0.21) in the risk of deep vein thrombosis.

CONCLUSIONS

We conclude that antifibrinolytic agents significantly decrease blood loss, blood transfusion, and there is no increase in the risk of deep vein thrombosisfor transfusion requirements in spine surgery.

Epsilon aminocaproic acid for the prevention of delayed postoperative bleeding in retired racing greyhounds undergoing gonadectomy

OBJECTIVE

To evaluate the effects of epsilon aminocaproic acid (EACA) on the prevalence of postoperative bleeding in retired racing Greyhounds (RRG), and to assess its effects on selected thrombelastography (TEG) and fibrinolysis variables.

STUDY DESIGN

Double-blinded, prospective, randomized study.

METHODS

100 RRG had elective ovariohysterectomy or orchiectomy and were administered EACA or placebo for 3 days after surgery. TEG variables were analyzed preoperatively and 24, 48, and 72 hours after surgery.

RESULTS

Thirty percent (15/50) of RRG in the placebo group had delayed postoperative bleeding starting 36-48 hours after surgery compared with 10% (5/50) in the EACA group (P = .012). On the TEG variables, the slopes for R and K time were significantly different between treatment groups (P <.05); the R and K time decreased over time in the EACA group after surgery whereas they increased in the placebo group. The angle, maximal amplitude (MA), and G slopes were also significantly different between treatment groups (P = .001, .001, and .006, respectively). The angle, MA, and G increased postoperatively over time in the EACA group and decreased in the placebo group. All these changes are supportive of hypercoagulability associated with EACA administration.

CONCLUSION

Postoperative administration of EACA significantly decreased the prevalence of postoperative bleeding in RRG undergoing surgery by increasing the clot strength.

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.