High Concentrations of Tranexamic Acid Inhibit Ionotropic Glutamate Receptors

The emerging role of tranexamic acid and its principal target, plasminogen, in skeletal health

The worldwide burden of skeletal diseases such as osteoporosis, degenerative joint disease and impaired fracture healing is steadily increasing. Tranexamic acid (TXA), a plasminogen inhibitor and anti-fibrinolytic agent, is used to reduce bleeding with high effectiveness and safety in major surgical procedures. With its widespread clinical application, the effects of TXA beyond anti-fibrinolysis have been noticed and prompted renewed interest in its use. Some clinical trials have characterized the effects of TXA on reducing postoperative infection rates and regulating immune responses in patients undergoing surgery. Also, several animal studies suggest potential therapeutic effects of TXA on skeletal diseases such as osteoporosis and fracture healing. Although a direct effect of TXA on the differentiation and function of bone cells in vitro was shown, few mechanisms of action have been reported. Here, we summarize recent findings of the effects of TXA on skeletal diseases and discuss the underlying plasminogen-dependent and -independent mechanisms related to bone metabolism and the immune response. We furthermore discuss potential novel indications for TXA application as a treatment strategy for skeletal diseases.

The effect of tranexamic acid on intraoperative blood loss in patients undergoing brain meningioma resections: Study protocol for a randomized controlled trial

INTRODUCTION

Tranexamic acid (TXA) has been proven to prevent thrombolysis and reduce bleeding and blood transfusion requirements in various surgical settings. However, the optimal dose of TXA that effectively reduce intraoperative bleeding and blood product infusion in patients undergoing neurosurgical resection of meningioma with a diameter ≥ 5 cm remains unclear.

METHODS

This is a single-center, randomized, double-blinded, paralleled-group controlled trial. Patients scheduled to receive elective tumor resection with meningioma diameter ≥ 5 cm will be randomly assigned the high-dose TXA group, the low-dose group, and the placebo. Patients in the high-dose TXA group will be administered with a loading dose of 20 mg/kg TXA followed by continuous infusion TXA at a rate of 5 mg/kg/h. In the low-dose group, patients will receive the same loading dose of TXA followed by a continuous infusion of normal saline. In the control group, patients will receive an identical volume of normal saline. The primary outcome is the estimated intraoperative blood loss calculated using the following formula: collected blood volume in the suction canister (mL)-the volume of flushing (mL) + the volume from the gauze tampon (mL). Secondary outcomes include calculated intraoperative blood loss, intraoperative coagulation function assessed using thromboelastogram (TEG), intraoperative cell salvage use, blood product infusion, and other safety outcomes.

DISCUSSION

Preclinical studies suggest that TXA could reduce intraoperative blood loss, yet the optimal dose was controversial. This study is one of the early studies to evaluate the impact of intraoperative different doses infusion of TXA on reducing blood loss in neurological meningioma patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05230381. Registered on February 8, 2022.

[Topical Application of Tranexamic Acid in Subcutaneous Mastectomy Wounds in Female-to-male Transgender Patients]

INTRODUCTION

Tranexamic acid (TXA) is an antifibrinolytic drug that can be used to treat and prevent bleeding. Its application in plastic and reconstructive surgery has been very limited to date. To our knowledge, there is a lack of published data on the topical application of TXA in transgender patients undergoing subcutaneous mastectomy.

METHODS

We performed a retrospective data analysis of female-to-male transgender patients who underwent subcutaneous mastectomy. A total of 22 patients were treated with topical TXA, while 29 patients served as controls. The primary endpoint was the amount of wound secretion in the first 48 hours after surgery. Secondary endpoints were the duration of drainage and the occurrence of postoperative bleeding.

RESULTS

Within the first 48 hours, the TXA group had an average drain volume of 97±50 ml compared with 180±111 ml in the control group (p<0.01). There was a significantly lower flow rate over the entire period in the group of TXA patients (113±86 ml vs. 265±197 ml). The time of drains in situ was 2.3±0.7 days in TXA patients, while the drains in the control group were in place for an average of 3.4±1.3 days (p<0.01). In the group of patients treated with TXA, there was a tendency towards a lower number of postoperative bleeding and haematoma (9vs. 17%).

DISCUSSION

There was a significant reduction in the amount of drain fluid within the first 48 hours and over the entire period after topical application of TXA. Also there was a reduction in the length of time patients had a drain in place in the TXA-treated patients. This study demonstrated a significant advantage for the topical application of TXA in subcutaneous mastectomy in female-to-male transgender patients.

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.

Safety and Efficacy of Local Tranexamic Acid for the Prevention of Surgical Bleeding in Soft-Tissue Surgery: A Review of the Literature and Recommendations for Plastic Surgery

Background:

Although high-bleed surgery routinely utilizes the antifibrinolytic drug tranexamic acid, most plastic surgical procedures are conducted in soft tissue with low-volume bleeding. Unease regarding possible systemic adverse effects prevents widespread systemic use, but local use of tranexamic acid is gaining popularity among plastic surgeons. Randomized controlled trials on topical use of tranexamic acid are mainly from high-bleed surgeries, and few studies address the effect in soft tissue. This article reviews the scientific evidence regarding local use of tranexamic acid in soft-tissue surgery, discusses pharmacological effects and possible adverse reactions, and presents recommendations for use in plastic surgery.

Methods:

A systematic search of databases for studies on local use of tranexamic acid in soft-tissue surgery was performed. Randomized controlled trials were included for a systematic review on effect; a narrative review regarding other clinically relevant aspects is based on extensive literature searches combined with the authors’ own research.

Results:

Fourteen randomized controlled trials, including 1923 patients, were included in the systematic review on local use of tranexamic acid in soft-tissue surgery.

Conclusions:

Local use of tranexamic acid may reduce blood loss comparably to intravenous prophylactic use with negligible risk of systemic adverse effects, but high-quality randomized controlled trials are few. Prolonged exposure to high local concentrations is discouraged, and direct contact with the central nervous system may cause seizures. No single superior means of administration or dosage is supported in the literature, and lowest effective dose is unknown. There may not be one single ideal dosing regimen, but rather many possibilities adaptable for different surgical situations.

Safety of intravenous tranexamic acid in patients undergoing supratentorial meningiomas resection: protocol for a randomised, parallel-group, placebo control, non-inferiority trial

INTRODUCTION

Growing evidence recommends antifibrinolytic agent tranexamic acid (TXA) to reduce blood loss and transfusions rate in various surgical settings. However, postoperative seizure, as one of the major adverse effects of TXA infusion, has been a concern that restricts its utility in neurosurgery.

METHODS AND ANALYSIS

This is a randomised, placebo-controlled, non-inferiority trial. Patients with supratentorial meningiomas and deemed suitable for surgical resection will be recruited in the trial. Patients will be randomised to receive either a single administration of 20 mg/kg TXA or a placebo of the same volume with a 1:1 allocation ratio after anaesthesia induction. The primary endpoint is the cumulative incidence of early postoperative seizures within 7 days after craniotomy. Secondary outcomes include the incidence of non-seizure complications, changes of haemoglobin level from baseline, intraoperative blood loss, erythrocyte transfusion volume, Karnofsky Performance Status, all-cause mortality, and length of stay, and total hospitalisation cost.

ETHICS AND DISSEMINATION

This trial is registered at ClinicalTrial.gov and approved by the Chinese Ethics Committee of Registering Clinical Trials (ChiECRCT20200224). The findings will be disseminated in peer-reviewed journals and presented at national or international conferences relevant to subject fields.

TRIAL REGISTRATION NUMBER

NCT04595786.

Antifibrinolytic Drugs for the Prevention of Bleeding in Pediatric Cardiac Surgery on Cardiopulmonary Bypass: A Systematic Review and Meta-analysis

BACKGROUND

Bleeding is one of the commonest complications affecting children undergoing cardiac surgery on cardiopulmonary bypass. Antifibrinolytic drugs are part of a multifaceted approach aimed at reducing bleeding, though sufficiently sized pediatric studies are sparse, and dosing algorithms are heterogeneous. Our objective was to evaluate the efficacy and safety of antifibrinolytic agents as well as the effectiveness of different dosing regimens in pediatric cardiac surgery using cardiopulmonary bypass.

METHODS

We performed a systematic review and meta-analysis evaluating randomized controlled trials published between 1980 and 2019, identified by searching the databases MEDLINE, EMBASE, PubMed, and CENTRAL. All studies investigating patients <18 years of age without underlying hematological disorders were included. The primary outcome was postoperative bleeding; secondary end points included blood product transfusion, mortality, and safety (thromboses, anaphylaxis, renal or neurological dysfunction, and seizures). Different dosing regimens were compared. Studies were dual appraised, outcomes were reported descriptively and, if appropriate, quantitatively using the Review Manager 5 (REVMAN 5) software (The Cochrane Collaboration).

RESULTS

Thirty of 209 articles were included, evaluating the following drugs versus control: aprotinin n = 14, tranexamic acid (TXA) n = 12, and epsilon-aminocaproic acid (EACA) n = 4. The number of participants per intervention group ranged from 11 to 100 (median, 25; interquartile range [IQR], 20.5) with a wide age span (mean, 13 days to 5.8 years) and weight range (mean, 3.1-26.3 kg). Methodological quality was low to moderate.All agents reduced mean 24-hour blood loss compared to control: aprotinin by 6.0 mL/kg (95% confidence interval [CI], -9.1 to -3.0; P = .0001), TXA by 9.0 mL/kg (95% CI, -11.3 to -6.8; P < .00001), and EACA by 10.5 mL/kg (95% CI, -21.1 to 0.0; P = .05). Heterogeneity was low for TXA (I2 = 29%; P = .19), moderate for aprotinin (I2 = 41%; P = .11), and high for EACA (I2 = 95%; P = <.00001). All agents also reduced 24-hour blood product transfusion. There was no clear dose-response effect for TXA nor aprotinin. Studies were underpowered to detect significant differences in mortality, thromboses, anaphylaxis, and renal or neurological dysfunction.

CONCLUSIONS

The available data demonstrate efficacy for all 3 antifibrinolytic drugs. Therefore, the agent with the most favorable safety profile should be used. As sufficient data are lacking, large comparative trials are warranted to assess the relative safety and appropriate dosing regimens in pediatrics.

Ventriculolumbar perfusion and inhalational anesthesia with sevoflurane in an accidental intrathecal injection of tranexamic acid: unreported treatment options

BACKGROUND

Tranexamic acid (TXA) decreases hemorrhage-related mortality in trauma patients and is increasingly being used during obstetric and orthopedic surgeries. Inadvertent intrathecal injection of TXA is a rare, potentially lethal event leading to dose-dependent cardiotoxicity and neurotoxicity. TXA enhances neuronal excitation by antagonizing inhibitory γ-aminobutyric acid type A and glycine receptors. Until now, mechanistic-based pharmacological treatments targeting multiple central nervous system receptors have been advocated for use in such cases, with no data on intrathecal TXA elimination techniques.

CASE PRESENTATION

A patient scheduled for hip surgery accidentally received 350 mg of intrathecal TXA instead of levobupivacaine. The clinical picture progressed from spinal segmental myoclonus to generalized convulsions and malignant arrhythmias. The treatment consisted of ventriculolumbar perfusion with normal saline at a rate of 50 mL/hour starting 5 hours after TXA administration and inhalational sedation with sevoflurane, in addition to drugs acting on multiple receptors at different central nervous system levels. Over 2 months the neurological status improved, although it was not complete.

CONCLUSIONS

For the first time, the feasibility and possible clinical efficacy of combined treatment with ventriculolumbar perfusion and inhalational sedation with sevoflurane were demonstrated. A referral to a neurosurgical facility is recommended in patients with acute TXA-induced neurotoxicity and cardiotoxicity.

Cytotoxicity and effect on wound re-epithelialization after topical administration of tranexamic acid

Background

Topical administration of tranexamic acid (TXA) reduces bleeding from surgical wounds similarly to intravenous use, but with negligible risk of adverse systemic events. Topical use is expanding, but is off‐label. Surgeons lack guidelines regarding safe topical dosages and modes of administration. The effects of topical TXA on skin cells and wound healing are unknown. This study investigated whether topical TXA might be cytotoxic or affect wound re‐epithelialization.

Methods

Human keratinocytes and fibroblast cell cultures and an ex vivo human skin wound model were subjected to both short (limited) and long (chronic) exposure to various clinically relevant concentrations of TXA to mimic different modalities of topical administration. Cytotoxicity and effects on wound re‐epithelialization were evaluated.

Results

In cell culture, toxicity from chronic exposure was associated with increasing concentration and exposure time. Limited exposure to TXA did not cause significant cytotoxicity even at high concentrations. Re‐epithelialization was completely absent in wounds chronically exposed to TXA concentrations of 25 mg/ml or above, and 50–100 mg/ml induced epidermolysis of normal epithelium, possibly by a non‐toxic mechanism. Wound re‐epithelialization was slightly delayed, but not impaired, by limited exposure to 100 mg/ml or chronic exposure to 6·25 mg/ml.

Conclusion

Although short exposure to even high concentrations of topical TXA seems well tolerated in vitro, prolonged exposure can be cytotoxic and may affect wound re‐epithelialization. Surgeons should adjust the TXA concentration to the planned mode of topical administration in clinical practice.

Neurologic Considerations and Complications Related to Liver Transplantation

Neurologic complications of surgery can be devastating. The authors review neurologic considerations and complications associated with liver transplantation and discuss strategies to prevent, identify, and treat such adverse outcomes in the perioperative period.

[Prophylactic use of tranexamic acid in noncardiac surgery : Update 2017]

BACKGROUND

Minimising perioperative bleeding is a key goal of "patient blood management" programs. One component of respective strategies includes preventive inhibition of fibrinolysis using protease inhibitors, such as tranexamic acid (TXA). TXA inhibits plasminogen activation and plasmin-induced fibrin degradation.

OBJECTIVES

The present article provides an overview of the existing literature and TXA applications in the prophylaxis of perioperative bleeding.

METHODS

Literature search in PubMed/MEDLINE (U.S. National Library of Medicine®, Bethesda, MD, USA).

RESULTS

TXA reduces perioperative blood loss and transfusion requirements in several randomized controlled trials (RCTs) and meta-analyses in the field of hip and knee arthroplasty for both intravenous and topical use. Moreover, evidence favours use of TXA in complex spine surgery and reconstructive surgery (e. g. craniosynostosis in children). Single RCTs showed benefits of TXA in abdominal hysterectomy, open prostatectomy, liver surgery and actively bleeding trauma patients. For prophylaxis of peripartum haemorrhage (PPH) following vaginal delivery or Caesarean section, TXA cannot be routinely recommended, although evidence points to benefits in actively bleeding patients. A recommendation exists for the treatment of (active) PPH. For prophylactic perioperative administration, different dosage regimens exist for adults. Most often an initial i. v. bolus of 1 g or 10-15 mg/kg body weight with/without repetition after 6 h or continuous infusions over 8 h is administered. Increased rates of thromboembolic events were not noted.

CONCLUSION

Protease inhibitors such as TXA reduce perioperative blood loss and transfusion requirements in selected surgical fields.