Effective tranexamic acid concentration for 95% inhibition of tissue-type plasminogen activator induced hyperfibrinolysis in children with congenital heart disease: A prospective, controlled, in-vitro study

Hemostatic effects of tranexamic acid in cardiac surgical patients with antiplatelet therapy: a systematic review and meta-analysis

BACKGROUND

The purpose of the current study was to assess the efficacy of tranexamic acid (TXA) on reducing bleeding in cardiac surgical patients with preoperative antiplatelet therapy (APT).

METHODS

Five electronic databases were searched systematically for randomized-controlled trials (RCTs) assessing the impact of intravenous TXA on post-operative bleeding on cardiac surgical patients with preoperative APT until May 2024. Primary outcome of interest was post-operative blood loss. Secondary outcomes of interest included the incidence of reoperation due to post-operative bleeding, post-operative transfusion requirements of red blood cells (RBC), fresh-frozen plasma (FFP), and platelet concentrates. Mean difference (MD) with 95% confidence interval (CI) or odds ratios (OR) with 95% CI was employed to analyze the data. Subgroup and meta-regression analyses were performed to assess the possible influence of TXA administration on reducing bleeding and transfusion requirements.

RESULTS

A total of 12 RCTs with 3018 adult cardiac surgical patients (TXA group, 1510 patients; Control group, 1508 patients) were included. The current study demonstrated that TXA significantly reduced post-operative blood loss (MD =  - 0.38 L, 95% CI: - 0.73 to - 0.03, P = 0.03; MD =  - 0.26 L, 95% CI: - 0.28 to - 0.24, P < 0.00001; MD =  - 0.37 L, 95% CI: - 0.63 to - 0.10, P = 0.007) in patients receiving dual antiplatelet therapy (DAPT), aspirin, or clopidogrel, respectively. Patients in TXA group had significantly lower incidence of reoperation for bleeding as compared to those in Control group. The post-operative transfusion of RBC and FFP requirements was significantly lower in TXA group than Control group. Subgroup analyses showed that studies with DAPT discontinued on the day of surgery significantly increased the risk of post-operative blood loss [(MD: - 1.23 L; 95% CI: - 1.42 to - 1.04) vs. (MD: - 0.16 L; 95% CI: - 0.27 to - 0.05); P < 0.00001 for subgroup difference] and RBC transfusion [(MD: - 3.90 units; 95% CI: - 4.75 to - 3.05) vs. (MD: - 1.03 units; 95% CI: - 1.96 to - 0.10); P < 0.00001 for subgroup difference] than those with DAPT discontinued less than 5-7 days preoperatively.

CONCLUSIONS

This meta-analysis demonstrated that TXA significantly reduced post-operative blood loss and transfusion requirements for cardiac surgical patients with preoperative APT. These potential clinical benefits may be greater in patients with aspirin and clopidogrel continued closer to the day of surgery.

TRIAL REGISTRATION NUMBER

CRD42022309427.

Efficacy of local infiltration of tranexamic acid in subcutaneous surgery: A protocol from a single medical center

BACKGROUND

The purpose of this study was to explore efficacy of locally injected tranexamic acid (TXA) at a concentration of 1 mg/mL for reduction perioperative bleeding and postoperative complications in subcutaneous tumor excisions. We present the protocol and also compare results between the group of use antithrombotic group and not used.

METHODS

This is a retrospective study. Fifty-three patients were divided into 3 groups. Group 1 (n = 14): using antithrombotic drugs (antiplatelet or anticoagulants) with locally injected TXA. Group 2 (n = 17): using antithrombotic drugs without locally injected TXA. Group 3 (n = 22): not using antithrombotic drugs but with locally injected TXA. TXA was diluted to 1 mg/mL for use based on our experience. All patients were operated by 1 surgeon in 1 single medical center in Taipei from March 1st, 2020, to March 31st 2022. Outcomes such as the quality of perioperative surgical field and postoperative surgical complications were evaluated and compared. The quality of field was intraoperatively recorded by an assessment and photos from the surgeon. The statistical relationships between the complication rates were analyzed using χ2 test and a 1-way ANOVA by SPSS 25.

RESULTS

From Groups 1 and 3, a total of 36 patients, 29 patients had a clear surgical field during procedure. When comparing Groups 1 and 2, use of locally injected TXA had greater positive advantage in terms of a clearer vision whilst surgery (P = .031). Group 2 had more minor complications such as hematoma, severe ecchymosis, wound dehiscence, wound infection. By postoperatively reducing hematomas for 24 hours, it significantly reduce the incidence of abovementioned minor complications (P = .036). With the help of locally injected TXA, shorter time was required to remove drain, hence reducing duration of in-hospital stay.

CONCLUSION

The use of locally injected TXA whilst performing subcutaneous surgery on patients taking antithrombotic drugs is cost-effective. It could reduce bleeding and provide a more effective surgical field. In our study, favorable results were obtained from the use of diluted tranexamic acid (1 mg/mL) mixed with lidocaine, namely in clearing the surgical field as well as reducing postoperative surgical complications.

A New Low Dose of Tranexamic Acid for Decreasing the Rate of Blood Loss in Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis

BACKGROUND

Previous studies have demonstrated that the use of tranexamic acid (TXA) reduces blood loss and transfusion requirements in children undergoing scoliosis surgery. Although TXA is safe and effective, significant adverse events have been reported. Using the lowest effective dose of TXA is advisable. We evaluated a new low dosing regimen for TXA based on an improved pharmacokinetic model and therapeutic plasma concentration. The purpose of this study is to evaluate the effectiveness of this new low dosing regimen in reducing blood loss and transfusion requirements in patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion when compared with a control group who did not receive TXA.

METHODS

We retrospectively reviewed 90 consecutive patients with idiopathic scoliosis undergoing posterior spinal fusion at our institution from 2017 to 2020. Forty patients received TXA at the new dosing regimen (10 mg/kg load, 5 mg/kg/h infusion) and 50 patients were in the non-TXA control group. The same 2 orthopaedic surgeons, working as a team, performed all surgical procedures. We assessed the use of TXA as an independent risk factor for estimated blood loss and transfusion requirement after adjusting for age, surgical duration, body mass index, major coronal curve, and sex.

RESULTS

A comparison of the intraoperative cumulative blood loss in the 2 groups showed a significantly lower blood loss in the TXA group. (583.5±272.0 vs. 479.5±288.7 mL, P=0.03) This difference persisted when blood loss was calculated as percent of total blood volume and per vertebral level. Transfusion requirements were lower in the TXA group (4/50 patients vs. 0/40 patients, P=0.13). No patient in the TXA group required a blood transfusion during their hospitalization.

CONCLUSION

This study is the first to provide evidence that a new low dosing regimen of TXA can significantly reduce blood loss and transfusion requirements for idiopathic scoliosis patients and supports the need for a prospective, randomized clinical trial to confirm these findings.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Effective tranexamic acid concentration for 95% inhibition of tissue-type plasminogen activator-induced hyperfibrinolysis in full-term pregnant women: a prospective interventional study

Postpartum haemorrhage is the leading cause of maternal mortality and morbidity worldwide. Tranexamic acid (TXA) has been shown to reduce blood loss and blood product transfusion requirements. Despite clinical evidence, further studies are needed to better define the pharmacokinetic and pharmacodynamic characteristics of TXA in pregnant women. The objective of our prospective observational ex-vivo study was to define the effective TXA concentration required to inhibit 95% (EC95) of tissue-type plasminogen activator (t-PA)-induced fibrinolysis in full-term pregnant women. Hyperfibrinolysis was induced by adding supraphysiologic concentration of t-PA to blood samples obtained from 30 full-term pregnant women and 10 healthy nonpregnant female volunteers. Increasing TXA concentrations (0--40 μg/ml) were then spiked into the blood samples and inhibition of fibrinolysis was assessed using the lysis index at 30 min of the ROTEM measured on EXTEM and NATEM tests. Effective TXA concentrations required to achieve EC95 were extrapolated using nonlinear regression. EC95 were compared between groups using an extra sum-of-squares F test. EC95 in pregnant women was 14.7 μg/ml (95% CI 12.4--17.5 μg/ml) on EXTEM and 11.2 μg/ml (95% CI 8.3--15.1 μg/ml) on NATEM tests. These values were significantly higher than those obtained in volunteers: 8.7 μg/ml (95% CI 5.5--13.9 μg/ml) and 6.8 μg/ml (95% CI 5.3--8.8 μg/ml), respectively (both P < 0.001). Our results suggest a higher fibrinolytic potential in pregnant women compared with nonpregnant women.

Is There a Role for Preoperative Local Infiltration of Tranexamic Acid in Elective Spine Surgery? A Prospective Randomized Controlled Trial Analyzing the Efficacy of Intravenous, Local Infiltration, and Topical Administration of Tranexamic Acid

STUDY DESIGN

Randomized control trial.

OBJECTIVE

The purpose of the study is to evaluate the safety and efficacy of tranexamic acid in reducing blood loss when administered through various routes in instrumented spine surgeries.

METHODS

A total of 104 patients undergoing instrumented spine surgery were randomly assigned to 4 groups (n = 26 in each group). Groups included (1) ivTXA-intravenous administration of tranexamic acid (TXA) 1 hour prior to surgery, (2) loTXA-local infiltration of TXA bilaterally into the paraspinal musculature prior to incision, (3) tTXA-topical application of TXA just before wound closure, and (4) control group. Outcome measures included intraoperative blood loss, postoperative blood loss, need for blood transfusion, length of hospital stay, and hematological parameters.

RESULTS

All the 3 different modes of TXA administration were found to be effective in reducing blood loss in the treated groups compared with the control group. Intraoperative blood loss was significantly reduced in ivTXA (223.6 ± 40.1 mL, P < .0001) and loTXA (256.07 ± 119 mL, P = .0039) groups when compared with controls (344 ± 88.5 mL).The postoperative blood loss was least in tTXA followed by ivTXA, loTXA, and controls. There was 67% reduction in need for blood transfusion in tTXA group, 55.5% reduction in ivTXA group, and 33% reduction in loTXA group when compared with the control group.

CONCLUSION

In instrumented spine surgery, ivTXA and loTXA were found to be equally effective in reducing the intraoperative blood loss. The tTXA has better postoperative blood conserving effects. This is the first study to detail about safety and efficacy on local infiltration of TXA in spine surgery, which is an effective and safe method for reducing intraoperative blood loss.

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).

Serum Concentrations and Pharmacokinetics of Tranexamic Acid after Two Means of Topical Administration in Massive Weight Loss Skin-Reducing Surgery

Supplemental Digital Content is available in the text.

Background:

Topical administration of tranexamic acid to reduce bleeding is receiving increasing attention, as it is inexpensive, simple, and possibly beneficial in most surgery. Concerns regarding potential systemic adverse effects such as thromboembolic events and seizures may prevent general use of tranexamic acid. Although serum concentrations after topical application are assumed to be low, proper pharmacokinetic studies of tranexamic acid after topical application are lacking.

Methods:

The authors have investigated systemic absorption of tranexamic acid after two means of topical administration in patients undergoing abdominoplasty after massive weight loss: a bolus of 200 ml of 5 mg/ml into the wound cavity versus moistening the wound surface with 20 ml of 25 mg/ml. Twelve patients were recruited in each group. Serum concentrations achieved were compared with those after administration of 1 g as an intravenous bolus to arthroplasty patients. Serial blood samples for tranexamic acid analysis were obtained for up to 24 hours.

Results:

After intravenous administration, the peak serum concentration was 66.1 ± 13.0 µg/ml after 6 ± 2 minutes. Peak serum concentration after topical moistening was 5.2 ± 2.6 µg/ml after 80 ± 33 minutes, and in the topical bolus group, it was 4.9 ± 1.8 µg/ml after 359 ± 70 minutes. Topical moistening resulted in homogenous and predictable absorption across the individuals included, whereas topical bolus administration caused variable and unpredictable serum concentrations.

Conclusion:

Topical administration of tranexamic acid in patients undergoing abdominoplasty results in low serum concentrations, which are highly unlikely to cause systemic effects.

Tranexamic acid and perioperative bleeding in children: what do we still need to know?

PURPOSE OF REVIEW

Perioperative bleeding and blood product transfusion are associated with significant morbidity and mortality. Prevention and optimal management of bleeding decreases risk and lowers costs. Tranexamic acid (TXA) is an antifibrinolytic agent that reduces bleeding and transfusion in a broad number of adult and pediatric surgeries, as well as in trauma and obstetrics. This review highlights the current pediatric indications and contraindications of TXA. The efficacy and safety profile, given current and evolving research, will be covered.

RECENT FINDINGS

Based on the published evidence, prophylactic or therapeutic TXA administration is a well-tolerated and effective strategy to reduce bleeding, decrease allogeneic blood product transfusion, and improve pediatric patients' outcomes. TXA is now recommended in recent guidelines as an important part of pediatric blood management protocols.

SUMMARY

Based on TXA pharmacokinetics, the authors recommend a dosing regimen of between 10 to 30 mg/kg loading dose followed by 5 to 10 mg/kg/h maintenance infusion rate for pediatric trauma and surgery. Maximal efficacy and minimal side-effects with this dosage regime will have to be determined in larger prospective trials including high-risk groups. Furthermore, future research should focus on determining the ideal TXA plasma therapeutic concentration for maximum efficacy and minimal side-effects.

Patient Blood Management in Pediatric Cardiac Surgery: A Review

Efforts to reduce blood product transfusions and adopt blood conservation strategies for infants and children undergoing cardiac surgical procedures are ongoing. Children typically receive red blood cell and coagulant blood products perioperatively for many reasons, including developmental alterations of their hemostatic system, and hemodilution and hypothermia with cardiopulmonary bypass that incites inflammation and coagulopathy and requires systemic anticoagulation. The complexity of their surgical procedures, complex cardiopulmonary interactions, and risk for inadequate oxygen delivery and postoperative bleeding further contribute to blood product utilization in this vulnerable population. Despite these challenges, safe conservative blood management practices spanning the pre-, intra-, and postoperative periods are being developed and are associated with reduced blood product transfusions. This review summarizes the available evidence regarding anemia management and blood transfusion practices in the perioperative care of these critically ill children. The evidence suggests that adoption of a comprehensive blood management approach decreases blood transfusions, but the impact on clinical outcomes is less well studied and represents an area that deserves further investigation.

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

Fibrinolytic activation is a major and preventable source of bleeding in neonates and children undergoing cardiac surgery with cardiopulmonary bypass. Based on the existing literature (adult and pediatric; cardiac and noncardiac), prophylactic administration of antifibrinolytic agents can help reduce fibrinolytic activation, and consequently reduces perioperative bleeding and the requirement for blood product transfusion. Due to the increased risk of renal failure and mortality reported in adults undergoing cardiac surgery, aprotinin should not be considered as a safe option in neonates and children. Further well-designed studies would be required before the prophylactic administration of aprotinin could be considered in pediatric cardiac surgery. The lysine analogs, tranexamic acid and ϵ-aminocaproic acid,, should be considered as safe and effective antifibrinolytic agents. Although no major side effects have been reported following the administration of lysine analogs in children undergoing cardiac surgery, high-dose tranexamic acid should not be recommended in order to avoid the increased risk of clinical seizures. Despite the recent advances made in our understanding of the pharmacokinetics of tranexamic acid and ϵ-aminocaproic acid,, the optimal plasmatic concentration to be targeted remains unknown. Further studies are therefore urgently needed to better define the optimal dose regimen to be used in neonates and children. In the meantime, the dose regimen published in the most recent pharmacokinetic studies can be used. Although no studies have assessed the effect of massive bleeding and transfusion on the plasmatic concentrations of the lysine analogs, additional boluses might be considered in the presence of bleeding and/or when signs of fibrinolytic activations are observed on viscoelastic hemostatic assays.

What concentration of tranexamic acid is needed to inhibit fibrinolysis? A systematic review of pharmacodynamics studies

: Intravenous tranexamic acid (TXA) reduces death because of bleeding in patients with trauma and postpartum haemorrhage. However, in some settings intravenous injection is not feasible. To find different routes of administration, we first need to determine the minimal concentration of TXA in the blood that is required to inhibit fibrinolysis.We conducted a systematic review of in-vitro and in-vivo pharmacodynamics studies. We searched MEDLINE, EMBASE, OviSP, and ISI Web of Science from database inception to November 2017 for all in-vitro (including simulated clotting models) or in-vivo studies reporting the relationship between the TXA concentration in blood or plasma and any reliable measure of fibrinolysis.We found 21 studies of which 20 were in vitro and one was in vivo. Most in-vitro studies stimulated fibrinolysis with tissue plasminogen activator and measured fibrinolysis using viscoelastic, optical density, or immunological assays. TXA concentrations between 10 and 15 mg/l resulted in substantial inhibition of fibrinolysis, although concentrations between 5 and 10 mg/l were partly inhibitory.TXA concentrations of 10-15 mg/l may be suitable targets for pharmacokinetic studies, although TXA concentrations above 5 mg/l may also be effective.

Is combined use of intravenous and intraarticular tranexamic acid superior to intravenous or intraarticular tranexamic acid alone in total knee arthroplasty? A meta-analysis of randomized controlled trials

BACKGROUND

Tranexamic acid (TXA) has been proven to be effective in reducing blood loss and transfusion rate after total knee arthroplasty (TKA) without increasing the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE). Recently, an increasing number of studies have been interested in applying combined intravenous (IV) with intraarticular (IA) tranexamic acid in total knee arthroplasty. The purpose of this meta-analysis was to compare the blood loss and complications of combined TXA with IV TXA or IA TXA on TKA.

METHODS

Systematic search of literatures were conducted to identify related articles that were published in PubMed, MEDLINE, Embase, the Cochrane Library, SpringerLink, ClinicalTrials.gov, and Ovid from their inception to September 2016. All studies that compare blood loss and complications of combined TXA and IV TXA or IA TXA on TKA were included. Main outcomes were collected and analyzed by the Review Manager 5.3.

RESULTS

Five studies were included in the present meta-analysis. There was significant difference in total blood loss and blood volume of drainage when compared combined TXA group with IV TXA group or IA TXA group (P < 0.05). There was no difference in transfusion rate and thromboembolic complications when comparing combined TXA with IV TXA or IA TXA alone (P > 0.05).

CONCLUSIONS

Compared with administration of IA TXA or IV TXA alone on TKA, combined use of TXA has advantages in reducing total blood loss and blood volume of drainage without increasing the incidence of thromboembolic complications. We recommend combined TXA as the preferred option for patients undergoing TKA.