Use of antifibrinolytics in pediatric cardiac surgery: Where are we now?

Antifibrinolytic and Adjunct Hemostatic Agents: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To derive systematic-review informed, modified Delphi consensus regarding antifibrinolytic and adjunct hemostatic agents in neonates and children supported with extracorporeal membrane oxygenation (ECMO) for the Pediatric ECMO Anticoagulation CollaborativE consensus conference.

DATA SOURCES

A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021.

STUDY SELECTION

Use of antifibrinolytics (epsilon-aminocaproic acid [EACA] or tranexamic acid), recombinant factor VII activated (rFVIIa), or topical hemostatic agents (THAs).

DATA EXTRACTION

Two authors reviewed all citations independently, with a third independent reviewer resolving conflicts. Eleven references were used for data extraction and informed recommendations. Evidence tables were constructed using a standardized data extraction form.

MEASUREMENTS AND MAIN RESULTS

Risk of bias was assessed using the Quality in Prognosis Studies tool. The evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation system. Forty-eight experts met over 2 years to develop evidence-based recommendations and, when evidence was lacking, expert-based consensus statements for the management of bleeding and thrombotic complications in pediatric ECMO patients. A web-based modified Delphi process was used to build consensus via the Research And Development/University of California Appropriateness Method. Consensus was defined as greater than 80% agreement. One weak recommendation and three consensus statements are presented.

CONCLUSIONS

Evidence supporting recommendations for administration of antifibrinolytics (EACA or tranexamic acid), rFVIIa, and THAs were sparse and inconclusive. Much work remains to determine effective and safe usage strategies.

Evaluating the Effectiveness of Tranexamic Acid vs. Placebo in Cardiac Surgery: A Systematic Review and Meta-Analysis

Tranexamic acid (TXA), a potent antifibrinolytic agent, is widely used in cardiac surgical procedures worldwide to minimize surgical bleeding and reduce the need for perioperative blood transfusions. However, the use of TXA may increase the risk of coronary artery graft thrombosis, potentially leading to a higher occurrence of late thrombotic events. Some studies have suggested that drugs like TXA, aimed at decreasing bleeding during cardiac surgeries, may be associated with elevated risks of thrombotic complications or mortality. Conversely, the reduced need for blood transfusions could contribute to improved long-term outcomes. Thus, a systematic review and meta-analysis were undertaken to assess the efficacy of TXA in cardiac surgery patients. Searches were conducted in databases including PubMed and PubMed Central. Data were extracted, and their quality was assessed using the Cochrane risk of bias tool for randomized clinical trials (RCTs). A random effects model was used to compute the pooled prevalence and investigate heterogeneity using the I2 statistic. Subgroup analyses differentiated between experimental and placebo groups. Additionally, sensitivity analyses were performed to assess the robustness of the findings, and publication bias was examined. An overall sample size of 12,869 patients was included in the meta-analysis, derived from seven of the 10 selected articles. This pooled sample was used to conduct an analysis of TXA's efficacy in cardiac surgery patients. Subgroup analysis revealed a 95% heterogeneity and indicated a p-value of less than 0.05, favoring TXA over placebo in terms of better outcomes. Our research indicates a statistically significant relationship between the efficacy of TXA and the number of patients undergoing heart surgery. According to our findings, there is a pressing need to enhance this evidence base and conduct larger RCTs to better understand the benefits of using TXA, aiming to maintain a low risk of bleeding after both major and minor heart surgeries.

Selected 2022 Highlights in Congenital Cardiac Anesthesia

This article is a review of the highlights of pertinent literature of interest to the congenital cardiac anesthesiologist, and was published in 2022. After a search of the United States National Library of Medicine PubMed database, several topics emerged in which significant contributions were made in 2022. The authors of this manuscript considered the following topics noteworthy to be included in this review-intensive care unit admission after congenital cardiac catheterization interventions, antifibrinolytics in pediatric cardiac surgery, the current status of the pediatric cardiac anesthesia workforce in the United States, and kidney injury and renal protection during congenital heart 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.

Prophylactic Use of Antifibrinolytics During Pediatric Cardiac Surgery With Cardiopulmonary Bypass on Postoperative Bleeding and Transfusion: A Systematic Review and Meta-Analysis

OBJECTIVES

To determine the effect of intraoperative antifibrinolytics, including tranexamic acid (TXA), aminocaproic acid (EACA), or aprotinin, on bleeding in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).

DATA SOURCES

Relevant articles were systematically searched from Ovid MEDLINE, Ovid EMBASE, CINAHL, Cochrane Library, and Web of Science to November 15, 2021.

STUDY SELECTION

Abstracts were screened, and full texts were reviewed using predetermined inclusion and exclusion criteria using the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline.

DATA EXTRACTION

A standardized data extraction tool was used.

DATA SYNTHESIS

Sixty-eight studies including 28,735 patients were analyzed. TXA compared with placebo resulted in a mean decrease in chest tube output of 9.1 mL/kg (95% CI, 6.0-12.3 mL/kg), I2 equals to 65.2%, p value of less than 0.001, platelet requirement of 2.9 mL/kg (95% CI, 0.1-5.8 mL/kg), I2 =72.5%, p value less than 0.001 and plasma requirement of 4.0 mL/kg (95% CI, 0.6-7.2 mL/kg), I2 equals to 94.5%, p value less than0.001. Aprotinin compared with placebo resulted in a mean decrease in chest tube output of 4.3 mL/kg (2.4-6.2 mL/kg), I2 equals to 66.3%, p value of less than 0.001, platelet transfusion of 4.6 mL/kg (95% CI, 0.6-8.6 mL/kg), I2 equals to 93.6%, p value of less than 0.001, and plasma transfusion of 7.7 mL/kg (95% CI, 2.1-13.2 mL/kg), I2 equals to 95.3%, p value of less than 0.001. EACA compared with placebo resulted in a mean decrease in chest tube output of 9.2 mL/kg (2.3-21.0 mL/kg), I2 equals to 96.4%, p value of less than 0.001, RBC transfusion of 7.2 mL/kg (95% CI, 2.4-12.1 mL/kg), I2 equals to 94.5%, p value equals to 0.002, and platelet transfusion of 10.7 mL/kg (95% CI, 2.9-18.5 mL/kg), I2 equals to 0%, p value of less than 0.001. No statistical difference was observed in chest tube output when TXA was compared with aprotinin. Subgroup analysis of cyanotic patients showed a significant decrease in chest tube output, platelet requirement, and plasma requirement for patients receiving aprotinin. Overall, the quality of evidence was moderate.

CONCLUSIONS

Antifibrinolytics are effective at decreasing blood loss and blood product requirement in children undergoing cardiac surgery with CPB although the quality of evidence is only moderate.

Update on Applications and Limitations of Perioperative Tranexamic Acid

Tranexamic acid (TXA) is a potent antifibrinolytic with documented efficacy in reducing blood loss and allogeneic red blood cell transfusion in several clinical settings. With a growing emphasis on patient blood management, TXA has become an integral aspect of perioperative blood conservation strategies. While clinical applications of TXA in the perioperative period are expanding, routine use in select clinical scenarios should be supported by evidence for efficacy. Furthermore, questions regarding optimal dosing without increased risk of adverse events such as thrombosis or seizures should be answered. Therefore, ongoing investigations into TXA utilization in cardiac surgery, obstetrics, acute trauma, orthopedic surgery, neurosurgery, pediatric surgery, and other perioperative settings continue. The aim of this review is to provide an update on the current applications and limitations of TXA use in the perioperative period.

Prophylactic administration of tranexamic acid combined with thromboelastography-guided hemostatic algorithm reduces allogeneic transfusion requirements during pediatric resective epilepsy surgery: A randomized controlled trial

Background: Intraoperative bleeding and allogeneic transfusion remain common problems in pediatric resective epilepsy surgery. Tranexamic acid (TXA) is a widely recommended antifibrinolytic drug that reduces blood loss and transfusion requirements for bleeding patients. Thromboelastography (TEG)-guided hemostatic algorithm is commonly used in bleeding management. This trial was designed to validate the efficacy of a multimodal coagulation therapy involving continuous TXA infusion with TEG-guided hemostatic algorithm in reducing allogeneic exposure risk in pediatric resective epilepsy surgery.

Methods: Eighty-three children undergoing resective epilepsy surgery were randomized into a treatment group (Group T; n = 42) and a control group (Group C; n = 41). Group T received prophylactic TXA (10 mg/kg followed by 5 mg/kg/h) with TEG-guided hemostatic algorithm, whereas Group C received conventional coagulation management. The primary outcome was allogeneic transfusion rate during surgery, and the secondary outcomes were intraoperative blood loss, incidence of postoperative seizures, and thromboembolic events during hospitalization.

Results: The incidence of intraoperative allogeneic transfusion reduced by 34.7% with the use of a multimodal coagulation therapy (19.0% in Group T vs. 53.7% in Group C; RR 0.355, 95% CI 0.179–0.704; p = 0.001). This was mainly triggered by a significant reduction (44.1%) in intraoperative plasma transfusion (7.1% in Group T vs. 51.2% in Group C; RR 0.139, 95% CI 0.045–0.432; p = 0.000). The risk of intraoperative RBC transfusion was lower in Group T than in Group C, but the difference was not statistically significant (14.3% in Group T vs. 29.3% in Group C; RR 0.488, 95% CI 0.202–1.177; p = 0.098). No platelets were transfused in both groups. Further, 19 (45.2%) patients in Group T received fibrinogen concentrates guided by TEG data, whereas 1 (2.4%) patient in Group C received fibrinogen concentrates empirically. There were no significant differences in estimated blood loss and postoperative seizures between the two groups, and no thromboembolic events were observed after surgery.

Conclusion: Prophylactic administration of TXA combined with TEG-guided hemostatic algorithm can be an effective multimodal coagulation strategy for reducing allogeneic transfusion requirements during pediatric resective epilepsy surgery.

Clinical Trial Registration:www.chictr.org.cn/index.aspx, identifier ChiCTR1800016188.

Evaluation of the safety of tranexamic acid use in pediatric patients undergoing spinal fusion surgery: a retrospective comparative cohort study

Background

Pediatric spinal fusion may be associated with significant intraoperative blood loss, leading to complications from transfusion, hypoperfusion and coagulopathy. One emerging strategy to mediate these risks is by utilization of the anti-fibrinolytic agent tranexamic acid (TXA). However, concerns regarding potential adverse reactions, specifically postoperative seizures and thrombotic events, still exist. To assess these risks, we examined the perioperative morbidity of TXA use in a large national database.

Methods

Retrospective data from pediatric patients (age 18 years or younger), discharged between January 2013 to December 2015, who underwent primary or revision posterior spinal fusions, was collected from the Premier Perspective database (Premier, Charlotte, NC). Patients were stratified by TXA use and records were assessed for complications of new onset seizures, strokes, pulmonary embolisms (PE) or deep vein thromboses (DVT) occurring during the perioperative period.

Results

In this cohort of 2,633 pediatric patients undergoing posterior spinal fusions, most often to treat adolescent idiopathic scoliosis, 15% received TXA. Overall, adverse events were rare in this patient population. The incidence of seizure, stoke, PE, or DVT in the control group was 0.54% (95% CI, 0.31% to 0.94%) and not significantly different from the TXA group. There was no significant difference in the incidence of DVTs, and no incidences of stroke in either group. There were no new-onset seizures or PEs in patients who received TXA.

Conclusions

The use of TXA was not associated with an increased risk of adverse events including seizure, stroke, PE, and DVT. Our findings support the safety of TXA use in pediatric patients undergoing spinal fusion surgery.

Risk Factors of Thrombotic Complications and Antithrombotic Therapy in Paediatric Cardiosurgical Patients

The development of cardiosurgical care for paediatric and neonatal patients is undergoing the rapid growth. Complex, multi-stage reconstructive operations and the use of invasive monitoring are associated with high risk of venous and arterial thrombosis.

The cardiac surgery patient is inherently unique, since it requires controlled anticoagulation during cardiopulmonary bypass. Moreover, the most cardiovascular pediatric patients require antithrombotic measures over the perioperative period. In addition to medication support with the use of various groups of antithrombotic agents, vascular access management is justified in order to minimize the risk of thromboembolic complications, which can affect both the functional status, and common and inter-stage mortality.

The purpose of this review was to systematize the available data on risk factors contributing to the development of thrombotic complications in patients with congenital heart disease.

An information search was carried out using Internet resources (PubMed, Web of Science, eLibrary.ru); literature sources for period 2015–2020 were analysed. As a result of the analysis of the literature data age-dependent features of the haemostatic system, and associated with the defect pathophysiology, and undergone reconstructive interventions were described. The issues of pathophysiology of univentricular heart defects and risk factors associated with thrombosis were also covered.

Moreover, aspects of intraoperative anti-thrombotic support are discussed, as well as measures to prevent thromboembolic complications in this population.

Coordinated actions of haematologists, cardiologists, anaesthesiologists, intensivists, and cardiac surgeons will allow achieving a fine balance between risks of bleeding and thrombosis in the population of paediatric patients undergoing cardiovascular surgery. 

Managing the coagulopathy associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has allowed for significant surgical advancements, but accompanying risks can be significant and must be expertly managed. One of the foremost risks is coagulopathic bleeding. Increasing levels of bleeding in cardiac surgical patients at the time of separation from CPB are associated with poor outcomes and mortality. CPB-associated coagulopathy is typically multifactorial and rarely due to inadequate reversal of systemic heparin alone. The components of the bypass circuit induce systemic inflammation and multiple disturbances of the coagulation and fibrinolytic systems. Anticipating coagulopathy is the first step in managing it, and specific patient and procedural risk factors have been identified as predictors of excessive bleeding. Medication management pre-procedure is critical, as patients undergoing cardiac surgery are commonly on anticoagulants or antiplatelet agents. Important adjuncts to avoid transfusion include antifibrinolytics, and perfusion practices such as red cell salvage, sequestration, and retrograde autologous priming of the bypass circuit have varying degrees of evidence supporting their use. Understanding the patient's coagulation status helps target product replacement and avoid larger volume transfusion. There is increasing recognition of the role of point-of-care viscoelastic and functional platelet testing. Common pitfalls in the management of post-CPB coagulopathy include overdosing protamine for heparin reversal, imperfect laboratory measures of thrombin generation that result in normal or near-normal laboratory results in the presence of continued bleeding, and delayed recognition of surgical bleeding. While challenging, the effective management of CPB-associated coagulopathy can significantly improve patient outcomes.

The synergistic effect of tranexamic acid and ethamsylate combination on blood loss in pediatric cardiac surgery

Background:

Pediatric patients are at risk for bleeding after cardiac surgery. Administration of antifibrinolytic agents reduces postoperative blood loss.

Objective:

Evaluation of the efficacy of combined administration of tranexamic acid (TXA) and ethamsylate in the reduction of postoperative blood loss in pediatric cardiac surgery.

Methods:

This prospective randomized study included 126 children submitted for cardiac surgery, and they were allocated into three groups: control group (n = 42); TXA group (n = 42):- received only TXA; and combined ethamsylate TXA group (n = 42):- received a combination of TXA and ethamsylate. The main collected data included sternal closure time, the needs for intraoperative transfusion of blood and its products, the total amount of blood loss, and the amount of the whole blood and its products transfused to the patients in the first 24 postoperative hours.

Results:

Blood loss volume in the first 24 postoperative hours was significantly smaller in combined group than the TXA and control groups and was significantly smaller in the TXA group than the control group. The sternal closure time was significantly shorter in the combined group than the other 2 groups and significantly shorter in TXA than the control group. The amount of whole blood transfused to patients in the combined group during surgery and in the first postoperative 24 h was significantly smaller than the other 2 groups and smaller in TXA group than the control group during surgery.

Conclusion:

Combined administration of ethamsylate and TXA in pediatric cardiac surgery was more effective in reducing postoperative blood loss and whole blood transfusion requirements than the administration of TXA alone.

Transfusion Outcomes in Patients Undergoing Unifocalization and Repair of Tetralogy of Fallot With Major Aortopulmonary Collaterals

BACKGROUND

Surgical repair of tetralogy of Fallot and major aortopulmonary collaterals (TOF/MAPCAs) involves unifocalization of MAPCAs and reconstruction of the pulmonary arterial circulation. Surgical and cardiopulmonary bypass (CPB) times are long and suture lines are extensive. Maintaining patency of the newly anastomosed vessels while achieving hemostasis is important, and assessment of transfusion practices is critical to successful outcomes.

METHODS

Clinical, surgical, and transfusion data in patients with TOF/MAPCAs repaired at our institution (2013-2018) were reviewed. Types and volumes of blood products used in the perioperative period, in addition to the use of antifibrinolytics and/or procoagulants (factor VIII inhibitor bypassing activity [FEIBA]; anti-inhibitor coagulant complex), were assessed. Outcome measures included days on mechanical ventilation (DOMV), postoperative intensive care unit and hospital length of stay (LoS), and incidence of thrombosis.

RESULTS

Perioperative transfusion data from 279 patients were analyzed. Surgical (879 ± 175 minutes vs 684 ± 257 minutes) and CPB times (376 ± 124 minutes vs 234 ± 122 minutes) were longer in patients who received FEIBA than those who did not. Although the indexed volume of packed red blood cells (128.4 ± 82.2 mL/kg) and fresh frozen plasma (64.2 ± 41.1 mL/kg) was similar in patients who did and did not receive FEIBA, the amounts of cryoprecipitate (5.5 ± 5.2 mL/kg vs 5.8 ± 4.8 mL/kg) and platelets (19.5 ± 20.7 mL/kg vs 20.8 ± 13 mL/kg) transfused were more in those who did receive FEIBA.

CONCLUSION

Perioperative transfusion is an important component in the overall surgical and anesthetic management of patients with TOF/MAPCAs. The intraoperative use of FEIBA was not associated with a decrease in the amount of blood products transfused, DOMV, or LoS or with an increase in thrombotic complications.

High-dose versus low-dose tranexamic acid for paediatric craniosynostosis surgery: a double-blind randomised controlled non-inferiority trial

BACKGROUND

Tranexamic acid (TXA) reduces blood loss and transfusion in paediatric craniosynostosis surgery. The hypothesis is that low-dose TXA, determined by pharmacokinetic modelling, is non-inferior to high-dose TXA in decreasing blood loss and transfusion in children.

METHODS

Children undergoing craniosynostosis surgery were enrolled in a two-centre, prospective, double-blind, randomised, non-inferiority controlled trial to receive high TXA (50 mg kg^-1 followed by 5 mg kg^-1 h^-1) or low TXA (10 mg kg^-1 followed by 5 mg kg^-1 h^-1). Primary outcome was blood loss. Low dose was determined to be non-inferior to high dose if the 95% confidence interval (CI) for the mean difference in blood loss was above the non-inferiority margin of -20 ml kg^-1. Secondary outcomes were transfusion, TXA plasma concentrations, and biological markers of fibrinolysis and inflammation.

RESULTS

Sixty-eight children were included. Values were non-inferior regarding blood loss (39.4 [4.4] vs 40.3 [6.2] ml kg^-1 [difference=0.9; 95% CI: -14.2, 15.9]) and blood transfusion (21.3 [1.6] vs 23.6 [1.5] ml kg^-1 [difference=2.3; 95% CI: -2.1, 6.7]) between high-dose (n=32) and low-dose (n=34) groups, respectively. The TXA plasma concentrations during surgery averaged 50.2 (8.0) and 29.6 (7.6) μg ml^-1. There was no difference in fibrinolytic and inflammatory biological marker concentrations. No adverse events were observed.

CONCLUSIONS

Tranexamic acid 10 mg kg^-1 followed by 5 mg kg^-1 h^-1 is not less effective than a higher dose of 50 mg kg^-1 and 5 mg kg^-1 h^-1 in reducing blood loss and transfusion in paediatric craniosynostosis surgery.

CLINICAL TRIAL REGISTRATION

NCT02188576.

Safety and efficacy of tranexamic acid in paediatric cardiac surgery: study protocol for a double-blind randomised controlled trial

INTRODUCTION

An initial retrospective study suggested that tranexamic acid (TXA) administration increased the incidence of seizures in paediatric patients undergoing cardiac surgery. However, the efficacy of TXA in paediatric cardiac surgery remains unclear owing to the small sample sizes of the studies. Therefore, this study will investigate the efficacy and safety of TXA in paediatric patients undergoing cardiac surgery. We hypothesised that TXA may increase the incidence of postoperative seizures with no effect on postoperative allogeneic transfusion in paediatric patients undergoing cardiac surgery. The pragmatic study will provide important implications for paediatric cardiac surgery.

METHODS AND ANALYSIS

This will be a single-centre prospective, double-blind randomised controlled trial. The plan is to enrol in the study 2090 paediatric patients aged 31 days to 7 years who will be undergoing cardiac surgery with cardiopulmonary bypass (CPB). All eligible participants will be randomly assigned to either the TXA or placebo group by using a Web-based randomisation service in a 1:1 ratio. The primary safety end point will be postoperative seizures until hospital discharge, and the primary efficacy end point will be the volume of allogeneic red blood cell transfusion after termination of CPB. All patients will be followed up for 1 year postdischarge. All data will be analysed in accordance with the intention-to-treat principle.

ETHICS AND DISSEMINATION

This study was approved by the institutional review board of Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (No 20191195). Written informed consent will be obtained from the parents/legal guardian of each patient because all participants will be <18 years of age. The results of the trial will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Register (ChiCTR1900024131).