Epileptic seizures following cortical application of fibrin sealants containing tranexamic acid in rats

Safety assessment of tranexamic acid: real-world adverse event analysis from the FAERS database

Background

In recent years, with the continuous expansion of the application scope of Tranexamic acid (TXA), its usage has surged. Despite numerous studies demonstrating its powerful efficacy, concerns regarding its adverse reactions persist, necessitating comprehensive safety assessment. This study analyzed real-world data from the U.S. Food and Drug Administration to investigate TXA-related adverse events, aiming to elucidate its safety and optimize patient treatment.

Methods

The adverse drug event data concerning TXA from 2004 Q1 to 2023 Q3 were collected. Following data standardization, a variety of signal quantification techniques, including the reporting odds ratios, proportional reporting ratios, Bayesian confidence propagation neural network, and empirical Bayes geometric mean were used for analysis.

Results

After analyzing 16,692,026 adverse event reports, a total of 1,574 cases of adverse events related to TXA were identified, spanning 23 system organ classes and 307 preferred terms. In addition to the common thrombosis-related Vascular disorders (n = 386) and Cardiac disorders (n = 377), adverse reactions in the Nervous system disorders category were also observed (n = 785), including Myoclonus (n = 70), Status epilepticus (n = 43), and Myoclonic epilepsy (n = 17). Furthermore, this study uncovered adverse effects such as Renal cortical necrosis, Hepatic cyst rupture, and Vascular stent stenosis, which were not previously mentioned in the instructions. Although these occurred infrequently, they exhibited high signal strength. Both Retinal artery occlusion and Vascular stent thrombosis disorder were frequent and exhibited high signal strength as well. It is worth noting that 78 cases of adverse reactions were caused by confusion between incorrect product administration.

Conclusion

Our research suggests that TXA has some adverse reactions that are being overlooked. As a cornerstone medication in hemorrhage treatment, it's crucial to monitor, identify, and address these adverse reactions effectively.

Tranexamic Acid Irrigation in Liposuction: A Double-Blind, Half-Body, Randomized, Placebo-Controlled Trial

BACKGROUND

Hematomas are common complications following plastic and esthetic surgeries. Large and complex hematomas might result in prolonged hospitalization, further interventions, additional expenses, and poor esthetic outcome. Tranexamic acid (TXA), an antifibrinolytic agent, has long been used to reduce blood loss. Its use in the field of plastic surgery has gained popularity recently. Several studies have presented the ability of TXA to reduce blood loss, hematomas, and ecchymoses after liposuctions. However, the proper dose and the route of administration remained controversial.

OBJECTIVE

The objective of the study was to quantify the effect of a low dose of TXA in an irrigation method in reducing hematomas and ecchymoses following liposuction.

METHODS

A prospective randomized controlled trial was conducted. Following liposuction, 400 mg of TXA were administered in an irrigation protocol to one side of the body in each patient, while the other side was administered with saline. The patients were photographed on 1, 2, 4, and 11 post-operative days. Ecchymosis and hematoma were measured and rated.

RESULTS

No statistical difference was observed between the intervention and control groups in terms of RBC in liposuction area (p = 0.11), RBC in lipoaspirate (p = 0.79), bruising size on days 1, 2, 4, and 11 (p = 0.68, 0.21, 0.42, and 0.75), and average ecchymosis score on the same days (p = 0.34, 0.72, 0.09, and 1) CONCLUSIONS: The use of a low-dose TXA irrigation solution did not demonstrate a statistically significant difference in post-operative hematoma formations rates and subsequent ecchymosis size and scale.

LEVEL OF EVIDENCE II

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparison of blood loss between tranexamic acid-soaked absorbable Gelfoam and topical retrograde injection via drainage catheter plus clamping in cervical laminoplasty surgery

Background

To compare the safety and efficacy of tranexamic acid (TXA)-soaked absorbable Gelfoam and the retrograde injection of TXA through a drain with drain-clamping in degenerative cervical laminoplasty patients.

Methods

Patients were assigned into either TXA retrograde injection (TXA-RI), TXA-soaked absorbable Gelfoam (TXA-Gel), or control groups. The demographics, operative measurements, volume and length of drainage, length of hospital stay, complete blood cell count, coagulopathy, postoperative complications, and blood transfusion were recorded.

Results

We enrolled 133 patients, with 44, 44, and 45 in the TXA-RI, TXA-Gel, and control groups, respectively. The baseline characteristics did not differ significantly among the three groups. The TXA-RI group exhibited a lower volume and length of postoperative drainage compared to the TXA-Gel and control groups (126.60 ± 31.27 vs. 156.60 ± 38.63 and 275.45 ± 75.27 mL; 49.45 ± 9.70 vs 58.70 ± 10.46 and 89.31 ± 8.50 hours, all P < 0.01). The TXA-RI group also had significantly shorter hospital stays compared to the control group (5.31 ± 1.18 vs 7.50 ± 1.25 days, P < 0.05) and higher hemoglobin and hematocrit levels (12.58 ± 1.67 vs 11.28 ± 1.76 g/dL; 36.62 ± 3.66% vs 33.82 ± 3.57%, both P < 0.05) at hospital discharge. In the TXA-RI and TXA-Gel groups, the D-dimmer (DD) and fibrinogen (FIB) were significantly lower than those in the control group after surgery (P < 0.05). None of the patients required blood transfusion. No complications, including thromboembolic events, were reported.

Conclusion

Topical retrograde injection of TXA through a drain with drain-clamping at the conclusion of unilateral posterior cervical expansive open-door laminoplasty may effectively reduce postoperative blood loss and the length of hospital stays without increasing postoperative complications.

Efficacy and safety of tranexamic acid in aneurysmal subarachnoid hemorrhage: A meta-analysis of randomized controlled trials

INTRODUCTION

Tranexamic acid, as a traditional hemostatic agent, is commonly used to treat or prevent excessive blood loss. However, the role of tranexamic acid in promoting good clinical outcomes and reducing mortality and risk of adverse events during the treatment of aneurysmal subarachnoid hemorrhage remains unclear.

METHODS

In strict accordance with the inclusion and exclusion criteria, Cochrane Library, Embase, Web of Science, and PubMed databases were assessed for randomized controlled trials (published between 1980 and 2021). Data were analyzed using STATA 16.0 and RevMan 5.3. In addition, the fixed-effects model (M-H method) and effect size (risk difference; RD) were used as a pooled measure to combine data. We also performed a post hoc sensitivity analysis and subgroup analysis to evaluate each outcome with low heterogeneity.

RESULTS

A meta-analysis revealed that although tranexamic acid was related to less rebleeding (RD = -0.06; 95% CI [-0.09, -0.03]; P = 0.0006), there is evidence that it has no an effect on good clinical outcomes or mortality (RD = -0.01; 95% CI [-0.05, 0.02]; P = 0.51; RD = 0.00; 95% CI [-0.03, 0.04]; P = 0.91). Tranexamic acid was associated with increased hydrocephalus (RD = 0.04; 95% CI [0.01, 0.08]; P = 0.02) and seizure (RD = 0.04; 95% CI [0.00, 0.08]; P = 0.05). The incidence of thromboembolic complications or delayed cerebral ischemia was not different in the two groups (RD = -0.01; 95% CI [-0.04, 0.03]; P = 0.62; RD = 0.00; 95% CI [-0.03, 0.03]; P = 0.96), and significant drug-related overall adverse events were identified (RD = 0.02; 95% CI [0.00, 0.04]; P = 0.03).

CONCLUSIONS

These findings indicate that the routine use of tranexamic acid is not suggested for patients with aneurysmal subarachnoid hemorrhage.

Effect of tranexamic acid on thrombotic events and seizures in bleeding patients: a systematic review and meta-analysis

BACKGROUND

Tranexamic acid (TXA) reduces surgical bleeding and reduces death from bleeding after trauma and childbirth. However, its effects on thrombotic events and seizures are less clear. We conducted a systematic review and meta-analysis to examine the safety of TXA in bleeding patients.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, EMBASE and the Cochrane Central Register of Controlled trials from inception until June 1, 2020. We included randomized trials comparing intravenous tranexamic acid and placebo or no intervention in bleeding patients. The primary outcomes were thrombotic events, venous thromboembolism, acute coronary syndrome, stroke and seizures. A meta-analysis was performed using a random effects model and meta-regression analysis was performed to evaluate how effects vary by dose. We assessed the certainty of evidence using the grading of recommendations, assessment, development and evaluations (GRADE) approach.

RESULTS

A total of 234 studies with 102,681 patients were included in the meta-analysis. In bleeding patients, there was no evidence that TXA increased the risk of thrombotic events (RR = 1.00 [95% CI 0.93-1.08]), seizures (1.18 [0.91-1.53]), venous thromboembolism (1.04 [0.92-1.17]), acute coronary syndrome (0.88 [0.78-1.00]) or stroke (1.12 [0.98-1.27]). In a dose-by-dose sensitivity analysis, seizures were increased in patients receiving more than 2 g/day of TXA (3.05 [1.01-9.20]). Meta-regression showed an increased risk of seizures with increased dose of TXA (p = 0.011).

CONCLUSION

Tranexamic acid did not appear to increase the risk of thrombotic events in bleeding patients. However, because there may be dose-dependent increase in the risk of seizures, very high doses should be avoided.

Tranexamic acid use in a patient with sickle cell disease undergoing posterior scoliosis correction surgery: safely mitigating bleeding and vaso-occlusive crises

A 15-year-old female with 2-year post-menarchal adolescent idiopathic scoliosis and sickle cell disease (SCD) underwent posterior scoliosis correction surgery. SCD is associated with higher rates of surgical complications, and these patients require careful management to prevent vaso-occlusive sickle cell crises (VOSCC); scoliosis correction surgery can be associated with high morbidity and mortality, including significant blood loss. Multiple techniques were employed to successfully prevent VOSCC in this patient including a preoperative transfusion, meticulous haemostasis at osteotomy sites, not performing a costoplasty despite presence of a rib hump, maintenance of intraoperative mean arterial pressure below 70 mmHg, aggressive postoperative hydration and the use of intraoperative tranexamic acid (TXA). This is the first reported case of the use of TXA in a patient with SCD and scoliosis correction surgery. A satisfactory correction was achieved with a longer than average inpatient stay due to non-sickle cell pain and protracted wound ooze.

A Randomized Controlled Trial of Topical Application of Tranexamic Acid in Patients with Thoracolumbar Spine Trauma Undergoing Long-Segment Instrumented Posterior Spinal Fusion

Study Design

Prospective, randomized controlled trial.

Purpose

To evaluate the effect of topically applied tranexamic acid (TXA) on postoperative blood loss of neurologically intact patients with thoracolumbar spine trauma.

Overview of Literature

Few articles exist regarding the use of topical TXA for postoperative bleeding and blood transfusion in spinal surgery.

Methods

A total of 57 patients were operated on with long-segment instrumented fusion without decompression. In 29 patients, a solution containing 1 g of TXA (20 mL) was applied to the site of surgery via a drain tube after the spinal fascia was closed, and then the drain was clamped for 2 hours. The 28 patients in the control group received the same volume of normal saline, and clamping was performed using the same technique. The groups were compared for postoperative packed red cells (PRC) transfusion rate and drainage volume.

Results

The rate of postoperative PRC transfusion was significantly lower in the topical TXA group than in the control group (13.8% vs. 39.3%; relative risk, 0.35; 95% confidence interval, 0.13 to 0.97; p=0.03). The mean total drainage volume was significantly lower in the topical TXA group than in the control group (246.7±125 mL vs. 445.7±211.1 mL, p<0.01). No adverse events or complications were recorded in any patient during treatment over a mean follow-up period of 27.5 months.

Conclusions

The use of topically administered 1 g TXA in thoracic and lumbar spinal trauma cases effectively decreased postoperative transfusion requirements and minimized postoperative blood loss, as determined by the total drainage volume.

Systemic and Topical Use of Tranexamic Acid in Spinal Surgery: A Systematic Review

Study Design Combination of narrative and systematic literature reviews. Objectives Massive perioperative blood loss in complex spinal surgery often requires blood transfusions and can negatively affect patient outcome. Systemic use of the antifibrinolytic agent tranexamic acid (TXA) has become widely used in the management of surgical bleeding. We review the clinical evidence for the use of intravenous TXA as a hemostatic agent in spinal surgery and discuss the emerging role for its complementary use as a topical agent to reduce perioperative blood loss from the surgical site. Through a systematic review of published and ongoing investigations on topical TXA for spinal surgery, we wish to make spine practitioners aware of this option and to suggest opportunities for further investigation in the field. Methods A narrative review of systemic TXA in spinal surgery and topical TXA in surgery was conducted. Furthermore, a systematic search (using PRISMA guidelines) of PubMed (MEDLINE), EMBASE, and Cochrane CENTRAL databases as well as World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov (National Institutes of Health), and International Standard Randomized Controlled Trial Number registries was conducted to identify both published literature and ongoing clinical trials on topical TXA in spinal surgery. Results Of 1,631 preliminary search results, 2 published studies were included in the systematic review. Out of 285 ongoing clinical trials matching the search criteria, a total of 4 relevant studies were included and reviewed. Conclusion Intravenous TXA is established as an efficacious hemostatic agent in spinal surgery. Use of topical TXA in surgery suggests similar hemostatic efficacy and potentially improved safety as compared with intravenous TXA. For spinal surgery, the literature on topical TXA is sparse but promising, warranting further clinical investigation and consideration as a clinical option in cases with significant anticipated surgical site blood loss.

Tranexamic acid-associated seizures: Causes and treatment

Antifibrinolytic drugs are routinely used worldwide to reduce the bleeding that results from a wide range of hemorrhagic conditions. The most commonly used antifibrinolytic drug, tranexamic acid, is associated with an increased incidence of postoperative seizures. The reported increase in the frequency of seizures is alarming, as these events are associated with adverse neurological outcomes, longer hospital stays, and increased in‐hospital mortality. However, many clinicians are unaware that tranexamic acid causes seizures. The goal of this review is to summarize the incidence, risk factors, and clinical features of these seizures. This review also highlights several clinical and preclinical studies that offer mechanistic insights into the potential causes of and treatments for tranexamic acid–associated seizures. This review will aid the medical community by increasing awareness about tranexamic acid–associated seizures and by translating scientific findings into therapeutic interventions for patients. ANN NEUROL 2016;79:18–26

Minimizing Collateral Brain Injury Using a Protective Layer of Fibrin Glue: Technical Note

BACKGROUND

Neurosurgical procedures expose the brain surface to a constant risk of collateral injury. We describe a technique where the brain surface is covered with a protective layer of fibrin glue and discuss its advantages.

METHODS

A thin layer of fibrin glue was applied on the brain surface after its exposure in 34 patients who underwent different craniotomies for tumoral and vascular lesions. Data of 35 more patients who underwent standard microsurgical technique were collected as a control group. Cortical and pial injuries were evaluated using an intraoperative visual scale. Eventual abnormal signals at the early postoperative T2-weighted fluid-attenuated inversion recovery (T2FLAIR) magnetic resonance imaging (MRI) sequences were evaluated in oncological patients.

RESULTS

Total pial injury was noted in 63% of cases where fibrin glue was not used. In cases where fibrin glue was applied, a significantly lower percentage of 26% (P < 0.01) had pial injuries. Only 9% had injuries in areas covered with fibrin glue (P < 0.0001). Early postoperative T2FLAIR MRI confirmed the differences of altered signal around the surgical field in the two populations.

CONCLUSION

We propose beside an appropriate and careful microsurgical technique the possible use of fibrin glue as alternative, safe, and helpful protection during complex microsurgical dissections. Its intrinsic features allow the neurosurgeon to minimize the cortical manipulation preventing minor collateral brain injury.

Tranexamic acid--an old drug still going strong and making a revival

Experience with tranexamic acid, an indirect fibrinolytic inhibitor, started as soon as it was released from Shosuke Okamoto's lab in the early 1960s. It was first prescribed to females with heavy menstrual blood loss and to patients with hereditary bleeding disorders. Soon the indications were widened to elective surgery because of its blood saving effects. Contraindications are few, most important is ongoing venous or arterial thrombosis and allergy to tranexamic acid, and the doses has to be reduced in renal insufficiency. In randomized controlled trials, however, patients with other risk factors are excluded as well (patients with history of cardiovascular disease, thromboembolism, bleeding diathesis, renal failure with creatinine >250μmol/L, pregnancy, and patients on treatment with anticoagulants). Recent meta-analyses of several randomized controlled trials in orthopedic arthroplasty have shown that tranexamic acid reduces peri- and postoperative blood loss, blood transfusion requirements and reoperations caused by bleedings. In general, the preoperative dose was 10-15mg/kg i.v. (or 1g), followed or not, by one or two doses, some as continuous infusion i.v. To validate relationship between dose and effect more data are needed. No evidence was found of increased thromboembolic accidents or other adverse events in the patients on tranexamic acid compared to the control groups. In major cardiac surgery tranexamic acid has been used in a large number of controlled trials with various dosing schemes in which the highest dosages seem to be associated with neurotoxicity; therefore a maximum total dose of 100mg/kg especially in patients over 50years of age is recommended by ISMICS (International Society for Minimally Invasive Cardiothoracic Surgery). Other indications for tranexamic acid are reviewed here as well. In recent years the extensive trial in severe trauma with massive bleedings using tranexamic acid was presented, CRASH-2 (Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage) comprising more than 20,000 patients. It showed that the survival was increased when tranexamic acid was given early after the accident compared to placebo; further studies are taking place is this field to get more information. Of utmost importance is the ongoing WOMAN (World Maternal Antifibrinolytic) a randomized, double-blind, placebo controlled trial among 15,000 with clinical diagnosis of postpartum haemorrhage bearing in mind that each year a large number of women in low and middle income countries, die from causes related to childbirth. In summary, we consider tranexamic acid is a drug of great value to reduce almost any kind of bleeding, it is cheap and convenient to use and has principally few contraindications. It may be added, that tranexamic acid is included in the WHOs list of essential medicines.

Fibrin sealant to prevent subdural electrode migration during intracranial electroencephalographic monitoring in a patient with a large arachnoid cyst

Ensuring a stable position of intracranial electrode grids with good proximity to the cortical surface can be a technical challenge in patients with complex anomalous cerebral anatomy. This report illustrates the use of fibrin sealant to secure subdural electrodes to concave cortical surfaces during intracranial electroencephalographic monitoring for localization-related medically intractable epilepsy in a patient with a large arachnoid cyst.

Tranexamic acid concentrations associated with human seizures inhibit glycine receptors

Antifibrinolytic drugs are widely used to reduce blood loss during surgery. One serious adverse effect of these drugs is convulsive seizures; however, the mechanisms underlying such seizures remain poorly understood. The antifibrinolytic drugs tranexamic acid (TXA) and ε-aminocaproic acid (EACA) are structurally similar to the inhibitory neurotransmitter glycine. Since reduced function of glycine receptors causes seizures, we hypothesized that TXA and EACA inhibit the activity of glycine receptors. Here we demonstrate that TXA and EACA are competitive antagonists of glycine receptors in mice. We also showed that the general anesthetic isoflurane, and to a lesser extent propofol, reverses TXA inhibition of glycine receptor-mediated current, suggesting that these drugs could potentially be used to treat TXA-induced seizures. Finally, we measured the concentration of TXA in the cerebrospinal fluid (CSF) of patients undergoing major cardiovascular surgery. Surprisingly, peak TXA concentration in the CSF occurred after termination of drug infusion and in one patient coincided with the onset of seizures. Collectively, these results show that concentrations of TXA equivalent to those measured in the CSF of patients inhibited glycine receptors. Furthermore, isoflurane or propofol may prevent or reverse TXA-induced seizures.

Fibrin chain cross-linking, fibrinolysis, and in vivo sealing efficacy of differently structured fibrin sealants

In this study, we compared the sealing characteristics and efficacy of a fibrin sealant with reduced plasminogen (FS-rplg) and a fibrin sealant with aprotinin as a fibrinolysis inhibitor (FS-apr). The relevant sealing characteristics including clot structure, fibrin chain cross-linking, and clot lysis were tested in the laboratory. The sealing efficacy was then investigated in a follow-up animal model to determine differences in the in vivo sealing properties. A total of 46 animals were available for the final analysis with 23 animals in each treatment arm. In conclusion, we saw differences in vitro between FS-rplg and FS-apr in ultrastructure and α-chain cross-linking rates as well as in the rate of fibrinolysis. These differences may explain the significantly enhanced sealing efficacy in FS-apr compared to FS-rplg shown in vivo in a rabbit intestinal model.

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

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

Inadvertent intrathecal injection of tranexamic acid

Some factors have been identified as contributing to medical errors such as labels, appearance, and location of ampules. In this case report, inadvertent intrathecal injection of 80 mg tranexamic acid was followed by severe pain in the back and the gluteal region, myoclonus on lower extremities and agitation. General anesthesia was induced to complete surgery. At the end of anesthesia, patient developed polymyoclonus and seizures needing supportive care of the hemodynamic, and respiratory systems. He developed ventricular tachycardia treated with Cordarone infusion. The patient's condition progressively improved to full recovery 2 days after. Confusion between hyperbaric bupivacaine and tranexamic acid was due to similarities in appearance between both ampules.

Mortality associated with administration of high-dose tranexamic acid and aprotinin in primary open-heart procedures: a retrospective analysis

Introduction

Antifibrinolytic agents are commonly used during cardiac surgery to minimize bleeding. Because of safety concerns, aprotinin was withdrawn from the market in 2007. Since then, tranexamic acid (TXA) has become the antifibrinolytic treatment of choice in many heart centers. The safety profile of TXA has not been extensively studied. Therefore, the aim of this study was to evaluate safety and efficiency of TXA compared with aprotinin in cardiac surgery.

Methods

Since July 1, 2006, TXA has been administered at a dose of 50 mg/kg tranexamic acid before cardiopulmonary bypass (CPB) and 50 mg/kg into the priming fluid of the CPB. Prior to this, all patients were treated with aprotinin at a dose of 50,000 KIU per kilogram body weight. Safety was evaluated with mortality, biomarkers, and the diagnosis of myocardial infarction, ischemic stroke, convulsive seizures, and acute renal failure in the intensive care unit (ICU), intermediate care unit (IMCU), and hospital stay. Efficiency was evaluated by the need for transfusion of blood products and total postoperative blood loss.

Results

After informed consent, 893 patients were included in our database (557 consecutive patients receiving aprotinin and 336 patients receiving TXA). A subgroup of 320 patients undergoing open-heart procedures (105 receiving TXA and 215 receiving aprotinin) was analyzed separately. In the aprotinin group, a higher rate of late events of ischemic stroke (3.4% versus 0.9%; P = 0.02) and neurologic disability (5.8% versus 2.4%; P = 0.02) was found. The rate of postoperative convulsive seizures was increased in tendency in patients receiving TXA (2.7% versus 0.9%; P = 0.05). The use of TXA was associated with higher cumulative drainage losses (P_ANOVA < 0.01; P_time < 0.01) and a higher rate of repeated thoracotomy for bleeding (6.9% versus 2.4%; P < 0.01). In the subgroup of patients with open-chamber procedures, mortality was higher in the TXA group (16.2% TXA versus 7.5% aprotinin; P = 0.02). Multivariate logistic regression identified EURO score II and CPB time as additional risk factors for this increased mortality.

Conclusions

The use of high-dose TXA is questioned, as our data suggest an association between higher mortality and minor efficiency while the safety profile of this drug is not consistently improved. Further confirmatory prospective studies evaluating the efficacy and safety profile of TXA are urgently needed to find a safe dosage for this antifibrinolytic drug.

The role of fibrin sealants in orthopaedic surgery

Blood conservation, specifically the avoidance of allogeneic blood transfusion, is becoming an important aspect of preoperative planning and intraoperative decision making in orthopaedic surgery. Knee and hip arthroplasty, as well as certain spine procedures, place patients at risk of significant blood loss. Fibrin sealants are topically applied hemostatic agents that reduce the time required to achieve hemostasis as well as the volume of blood loss. Fibrin sealants may provide additional benefits beyond hemostasis, such as improvements in wound healing and postoperative range of motion as well as lower rates of wound infections.

Risk reduction of subdural collections following endoscopic third ventriculostomy

OBJECT

To evaluate the efficacy and safety using fibrin glue and absorbable hemostats for packing the endoscopic tract in a pediatric population in the prevention of subdural fluid collections after endoscopic third ventriculostomy.

MATERIALS AND METHODS

Twenty-one endoscopic third ventriculostomies were performed in 20 hydrocephalic children with a mean age of 22 months over a 4-year period using uniformly this technique. Six children, with age ranged 6 days to 22 months (mean 9 months), had severe ventriculomegaly with thin brain mantle less than 10 mm. There was no mortality and no permanent morbidity related to the endoscopic procedure. One child developed an asymptomatic collection, which could be managed conservatively and was most likely attributed to the young age of the child and the assumed poor cerebrospinal fluid absorption ability. Lost compliance of the brain parenchyma may play an additional role, which was not related to the thickness of the brain mantle. No adverse effects regarding the material used for sealing were observed over a mean follow-up of 23 months.

CONCLUSIONS

Subdural fluid collections could be prevented in 20 out of 21 procedures by using this technique regardless of the thickness of the brain mantle, the application of mixture of fibrin glue and hemostatic agents seems to be safe, and we consider this technique effective in reducing the risk of this potential complication.

The long-term neurocompatibility of human fibrin sealant and equine collagen as biomatrices in experimental spinal cord injury

INTRODUCTION

While fibrin sealant (FS) and equine collagen (EC) have been used as scaffold materials in experimental spinal cord injury (SCI), questions concerning neurocompatibility still remain. In this study, we assessed potential adverse effects, as well as functional and histological impact of FS and EC in subtotal hemisection of the thoracic spinal cord (SC) in rats.

METHODS

124 male rats were randomly assigned to four main groups (n=31): Sham (SH), Lesion only (L), fibrin sealant (GFS) and equine collagen group (GEC). SH animals received laminectomy only; all other animals underwent subtotal lateral hemisection at T9. Treatment consisted of application of FS or EC into the lesion gap in GFS and GEC, which was left empty in L. GFS, GEC, L and SH were each further divided into 4 subgroups: One subgroup, consisting of 10 rats was subjected to behavioural and reflex testing before surgery and followed up on days 1,7, 14, 21, 28 post op and then sacrificed. Haemalaun or cresyl violet (CV) was used to identify neutrophils in parasagittal cord sections which were obtained on day 1 (n=7). Sections stained for quantification of microglia/macrophages using ED-1 on day 3 (n=7), day 7 (n=7) and day 28 (n=7 out of 10). Additionally, neural filament (NF) staining was chosen to detect axonal regeneration and the length of ingrowth into FS and EC, Luxol blue for myelination, Von Willebrand factor for vascularisation, and glial fibrillary acidic protein (GFAP) staining for detection of astrocytes in glial scars on day 28.

RESULTS

No adverse effects were observed in the treatment groups. Compared to L, GFS and GEC performed significantly better in the Basso, Beattie, Bresnahan (BBB) score and hopping responses. Proprioceptive placing was markedly improved in FS and EC compared to L. Axonal regrowth was found in GFS and GEC--the regrowth in the GFS was accompanied by myelination and vascularisation. Glial scarring occurred in all groups. Discussion Both biomatrices improved functional recovery compared to L and no adverse effects were perceived.

Toward optimal tissue sealants for neurosurgery: use of a novel hydrogel sealant in a canine durotomy repair model

OBJECTIVE

Watertight dural repairs are difficult to achieve, and cerebrospinal fluid leakage causes complications and extends hospital stays. Therefore, a novel synthetic hydrogel film was evaluated as an adjunct to dural closure in a canine model.

METHODS

The self-polymerizing, absorbable, and biocompatible hydrogel was sprayed onto tissue and formed a flexible, adherent sealant. A 2-cm incision of cranial dura and arachnoid was created in 26 adult dogs and loosely repaired. Hydrogel was applied over the 2-mm dural gap in 13 dogs; 13 control dogs received no hydrogel application.

RESULTS

All dogs remained neurologically intact. Valsalva tests conducted at 1, 4, 7, and 56 days were associated with mean leakage pressures (+/- standard error of the mean) of 5 +/- 0, 5 +/- 0, 7 +/- 2, and 13 +/- 8 cm H(2)O in the controls and of 53 +/- 2, 37 +/- 11, 42 +/- 6, and 48 +/- 4 in the treated animals (P = 0.001, 0.053, 0.010, 0.035, respectively, at each time point; one-tailed t test). Histopathological analysis revealed minimal changes.

CONCLUSION

The hydrogel-treated animals exhibited normal progression of dural healing, no dural adhesions, and no underlying effects on the brain. Although dural healing progressed normally, the control animals displayed marked peridural adhesions. The results of this in vivo study suggest that hydrogels, such as that used here, may significantly decrease cerebrospinal fluid leakage, thereby increasing the safety and effectiveness of dural closure in patients and facilitating surgical reexploration.

Effect of tranexamic acid incorporated in fibrin sealant clots on the cell behavior of neuronal and nonneuronal cells

Fibrin sealants are commonly used for hemostasis following surgery on various types of tissues. Aprotinin, an effective fibrinolysis inhibitor, is one of the components in some fibrin sealant products currently available. Tranexamic acid (tAMCHA) is another fibrinolysis inhibitor and is used as an alternative to aprotinin. Recent studies on fibrin sealant products containing tAMCHA indicate that it may be responsible for various adverse reactions when used in neurological applications. To determine a possible mechanism for such adverse reactions, we examined the effect of tAMCHA on the behavior of neuronal and nonneuronal cells using in vitro assays. The data indicate that different concentrations of tAMCHA incorporated in fibrin clots had no effect on the initial cell adhesion of either proliferative cells (glial cells and fibroblasts) or nonproliferative cells (neuronal cells) to the fibrin clots. Moreover, a high concentration of tAMCHA (300-450 mM) incorporated in the fibrin clots increased glial and fibroblast proliferation on fibrin clots. However, because tAMCHA is known to leach out of the fibrin clots, we have also examined the effect of solubilized tAMCHA in a growth medium on cells seeded on matrix-coated surfaces. A high concentration (300-450 mM) of tAMCHA detached all cell types from matrix-coated dishes. Our model suggests that tAMCHA in fibrin clots has no adverse effect on cells bound to the fibrin clots; however, tAMCHA leaching out from the fibrin clots reduces adhesion of adjacent cells bound to their natural extracellular matrix. Thus, a high concentration of tAMCHA should not be used as a fibrinolysis inhibitor in fibrin sealant products, especially in neurosurgery.

A comparison of fibrin sealants in relation to their in vitro and in vivo properties

INTRODUCTION

Fibrin sealants (FS) have been used for many years to facilitate hemostasis and to provide suture support and sealing/adhesion of tissues after surgery. While their composition is similar, different formulations, application devices, and varying concentrations of key components mean that the properties of clots formed by individual FS can be diverse.

MATERIALS AND METHODS

We performed several studies, including animal models, to compare the properties of 12 different commercially available FS/application device combinations using partial liver and kidney resection models to assess hemostatic efficacy and a novel pig skin model to measure adhesive clot strength. The quality of mixing was determined using colored spray images.

RESULTS

Although the FS tested shared the principle of combining fibrinogen and thrombin, major differences were found between the individual preparations with regard to hemostatic efficacy. Two pre-requisites for successful early hemostasis were identified--adequate clottable protein content and the ability of the application device to effectively mix the fibrinogen and thrombin components of the FS. Factor XIII activity was a key determinant in prevention of re-bleeding and premature clot lysis. Furthermore, FS lacking measurable factor XIII activity formed the weakest, softest clots.

CONCLUSIONS

Clearly, all FS are not the same, and their different characteristics may potentially translate into different clinical outcomes. In our studies, while all FS tested performed well on individual parameters, Beriplast P (Aventis Behring) was the foremost FS in consistently providing early hemostasis, minimizing the risk of re-bleeding, and providing strong adhesive clots capable of resisting mechanical forces.