Computational model of tranexamic acid on urokinase mediated fibrinolysis

Comparative efficacy and safety of high-dose versus low-dose tranexamic acid in adolescent idiopathic scoliosis: A systematic review and meta-analysis

OBJECTIVE

The objective of this meta-analysis was to evaluate the comparative effectiveness and safety of high-dose versus low-dose tranexamic acid (TXA) in adolescents undergoing treatment for idiopathic scoliosis.

METHODS

A comprehensive literature search was conducted across PubMed, Web of Science, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases up to March 2024. We sought to identify randomized controlled trials (RCTs) and retrospective controlled studies (RCSs) assessing the impact of high-dose compared to low-dose TXA on perioperative blood loss and transfusion requirements in spinal fusion procedures for adolescent idiopathic scoliosis. The study was registered in INPLASY (Registration number: INPLASY202480018).

RESULTS

Our meta-analysis included data from six studies: two high-quality RCTs and four lower-quality RCSs, comprising a total of 611 participants. Subgroup analysis revealed that high-dose TXA significantly reduced intraoperative blood loss and transfusion rates in RCSs, whereas no significant differences were observed in RCTs. The combined findings showed that high-dose TXA was associated with a significant reduction in intraoperative blood loss [weighted mean difference (WMD) =  -215.48, 95% confidence interval (CI) (-367.58, -63.37), P <  0.001], as well as a decreased likelihood of transfusion [risk ratio (RR) =  0.40, 95% CI (0.30, 0.53), P <  0.001]. Operative time did not differ significantly, and no thromboembolic events were reported in either treatment group. The differences between high and low doses varied widely across studies.

CONCLUSION

This meta-analysis indicates that high-dose TXA does not significantly reduce intraoperative blood loss, transfusion rates, or operative time compared to low-dose TXA in adolescent idiopathic scoliosis. While RCSs showed some benefit, our analysis places more emphasis on the results from RCTs, which did not show significant differences. Further high-quality RCTs are needed to confirm its effectiveness and safety.

Evaluation of the efficacy of perioperative tranexamic acid in patients with pelvic and acetabular fractures: A systematic review and meta-analysis

BACKGROUND

Tranexamic acid (TXA) is commonly used to reduce perioperative bleeding in various surgeries, including acetabular and pelvic fractures treated with open reduction and internal fixation (ORIF). However, research on TXA's effectiveness and safety in this context is conflicting. To address this, we conducted a systematic review and meta-analysis on TXA's efficacy and safety in patients with acetabular and pelvic fractures undergoing ORIF.

METHODS

We systematically searched Cochrane, PubMed, and EMBASE databases until August 30, 2023. Our evaluation of TXA focused on 6 domains: estimated blood loss (EBL), blood transfusion units, transfusion rates, thromboembolic events, other complications, and surgery duration. Data from these studies were analyzed using RevMan Manager 5.4.

RESULTS

This study included 4 randomized controlled trials with 179 patients with acetabular and pelvic fractures treated with TXA. The analysis showed that TXA did not significantly reduce EBL, packed red blood cell transfusion units, blood transfusion rates, or surgery duration. There was no significant difference in thromboembolic events or other postoperative complications, like surgical wound issues, pneumonia, heterotopic ossification, and sciatic nerve injuries, between the TXA and control groups.

CONCLUSION

TXA did not demonstrate a significant benefit in reducing perioperative bleeding or complications in patients treated with ORIF for acetabular and pelvic fractures. The utilization of TXA in such clinical scenarios remains a topic necessitating further rigorous investigation to delineate its role in this clinical setting.

Traumatic bleeding and mortality in mice are intensified by iron deficiency anemia and can be rescued with tranexamic acid

Background

Clinical evidence suggests that anemia exacerbates traumatic bleeding and worsens outcomes.

Objectives

To study the influence of iron deficiency anemia on traumatic bleeding, coagulopathy, and mortality.

Methods

C57BL/6J mice received an iron-deficient diet (8 weeks; ±1 mg intraperitoneal iron dextran 2 weeks before trauma). Control mice received a normal diet. Iron deficiency anemia was confirmed by hematocrit, red cell indices, and liver iron. Mice received saline or tranexamic acid (TXA; 10 mg/kg) just before liver laceration. Blood loss, coagulopathy (activated partial thromboplastin time, factor [F]II, FV, FVIII, FX, and fibrinogen), D-dimer, thrombin-antithrombin complexes, and plasmin-alpha-2-antiplasmin complexes were analyzed at 15 and 60 minutes, and a cytokine panel was performed at 60 minutes and 6 hours after trauma. Survival was monitored for 7 days.

Results

Compared with nonanemic mice, anemic mice had lower hematocrit and hepatic iron content. Anemic mice experienced higher blood loss compared with nonanemic mice, which was reduced by TXA. Both groups developed traumatic coagulopathy characterized by activated partial thromboplastin time prolongation, thrombin-antithrombin complex formation, and depletion of FV, FVIII, and fibrinogen. TXA corrected the coagulopathy. However, plasmin-alpha-2-antiplasmin complex formation and D-dimers, markers of fibrinolysis, were higher in anemic mice and were not corrected by TXA. Seven-day survival was low in anemic mice, and rescued by TXA, but high in nonanemic mice without additional improvement by TXA. Among cytokines, only interleukin-6 increased, which was prevented by TXA most notably in anemic mice.

Conclusion

These observations provide first and critical proof-of-principle evidence that anemia accelerates traumatic bleeding and increases mortality, which could be rescued by anemia correction (parenteral iron) or periprocedural TXA.

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.

Fibrinolytic-deficiencies predispose hosts to septicemia from a catheter-associated UTI

Catheter-associated urinary tract infections (CAUTIs) are amongst the most common nosocomial infections worldwide and are difficult to treat partly due to development of multidrug-resistance from CAUTI-related pathogens. Importantly, CAUTI often leads to secondary bloodstream infections and death. A major challenge is to predict when patients will develop CAUTIs and which populations are at-risk for bloodstream infections. Catheter-induced inflammation promotes fibrinogen (Fg) and fibrin accumulation in the bladder which are exploited as a biofilm formation platform by CAUTI pathogens. Using our established mouse model of CAUTI, here we identified that host populations exhibiting either genetic or acquired fibrinolytic-deficiencies, inducing fibrin deposition in the catheterized bladder, are predisposed to severe CAUTI and septicemia by diverse uropathogens in mono- and poly-microbial infections. Furthermore, here we found that Enterococcus faecalis, a prevalent CAUTI pathogen, uses the secreted protease, SprE, to induce fibrin accumulation and create a niche ideal for growth, biofilm formation, and persistence during CAUTI.

Intra-operative Tranexamic Acid Administration Significantly Decreases Incidence of Postoperative Bleeding Without Increasing Venous Thromboembolism Risk After Laparoscopic Sleeve Gastrectomy: a Retrospective Cohort Study of Over 400 Patients

BACKGROUND

There is evidence that tranexamic acid (TXA) reduces surgical bleeding and is widely used in trauma, obstetrics and other specialties. This practice is less well-established in laparoscopic sleeve gastrectomy (LSG) due to concerns surrounding venous thromboembolism (VTE); equally postoperative bleeding is a serious complication often requiring re-operation.

METHODS

This retrospective cohort study compared 30-day outcomes following primary LSG in patients receiving intra-operative TXA (March 2020-July 2022) to those who did not (March 2011-March 2020). The primary outcome was postoperative bleeding (Hb < 9 g/dL) requiring transfusion or re-operation. Secondary outcomes were incidence of VTE, serious postoperative complications (Clavien-Dindo > grade 3) and death. Patients underwent standardised-protocol LSG without staple line re-enforcement under a single surgeon within the independent sector (private practice). TXA 1 g intravenous was administered immediately after a methylene blue leak test, prior to extubation.

RESULTS

TXA group had 226 patients and non-TXA group had 192 patients. Mean age was 40.5 ± 10.3 and 39.1 ± 9.8 years, respectively. In the TXA group, no postoperative bleeds [versus 3 (1.6%) in non-TXA group, p = 0.0279] occurred. One staple line leak (0.4%) occurred in the TXA group compared to zero in the non-TXA group (p = ns). There was no VTE or death.

CONCLUSIONS

This is the largest cohort study of intra-operative TXA in primary LSG to date, which demonstrates significant decrease in postoperative bleeding without increasing VTE risk. The authors recommend administration of TXA immediately following leak test, or removal of bougie to maximise efficacy. Data of TXA in LSG is awaited from the randomised controlled PATAS trial.

Topical tranexamic acid (TXA) is non-inferior to intravenous TXA in adult spine surgery: a meta-analysis

Tranexamic acid (TXA) has long been utilized in spine surgery and can be administered through intravenous (IV) and topical routes. Although, topical and IV administration of TXA are both effective in decreasing blood loss during spine surgery, complications like deep vein thrombosis (DVT) and pulmonary embolism have been reported with the use of intravenous TXA (ivTXA). These potential complications may be mitigated through the use of topical TXA (tTXA). To assess optimal dosing protocols and efficacy of topical TXA in spine surgery, Embase, Ovid-MEDLINE, Scopus, Cochrane, and clinicaltrials.gov were queried for original research on the use of tTXA in adult patients undergoing spine surgery. Data parameters analyzed included blood loss, transfusion rate, thromboembolic, and other complications. Data was synthesized and confidence evaluated according to the Grades of Recommendation, Assessment, Development, and Evaluation approach. Nineteen studies were included in the final analysis with 2197 patients. Of the 18 published studies, 9 (50%) displayed high levels of evidence. Topical TXA showed a trend towards a lower risk of transfusion and complications. Protocols that used 1g tTXA showed a significantly reduced risk for transfusion when compared to controls (risk ratio -1.05, 95% CI (-1.62, -0.48); P = 0.94, I2 = 0%). Complications associated with tTXA included DVTs and wound infections. Topical TXA was non-inferior to intravenous TXA with similar efficacy and complication profiles for bleeding control in spine surgery; however, more studies are needed to discern benefits and risks.

Chemical Adjustment of Fibrinolysis

Fibrinolysis is the process of the fibrin-platelet clot dissolution initiated after bleeding has been stopped. It is regulated by a cascade of proteolytic enzymes with plasmin at its core. In pathological cases, the balance of normal clot formation and dissolution is replaced by a too rapid lysis, leading to bleeding, or an insufficient one, leading to an increased thrombotic risk. The only approved therapy for emergency thrombus lysis in ischemic stroke is recombinant tissue plasminogen activator, though streptokinase or urokinase-type plasminogen activators could be used for other conditions. Low molecular weight compounds are of great interest for long-term correction of fibrinolysis dysfunctions. Their areas of application might go beyond the hematology field because the regulation of fibrinolysis could be important in many conditions, such as fibrosis. They enhance or weaken fibrinolysis without significant effects on other components of hemostasis. Here we will describe and discuss the main classes of these substances and their mechanisms of action. We will also explore avenues of research for the development of new drugs, with a focus on the use of computational models in this field.

Fibrinolytic-deficiencies predispose hosts to septicemia from a catheter-associated UTI

Catheter-associated urinary tract infections (CAUTIs) are amongst the most common nosocomial infections worldwide and are difficult to treat due to multi-drug resistance development among the CAUTI-related pathogens. Importantly, CAUTI often leads to secondary bloodstream infections and death. A major challenge is to predict when patients will develop CAUTIs and which populations are at-risk for bloodstream infections. Catheter-induced inflammation promotes fibrinogen (Fg) and fibrin accumulation in the bladder which are exploited as a biofilm formation platform by CAUTI pathogens. Using our established mouse model of CAUTI, we identified that host populations exhibiting either genetic or acquired fibrinolytic-deficiencies, inducing fibrin deposition in the catheterized bladder, are predisposed to severe CAUTI and septicemia by diverse uropathogens in mono- and poly-microbial infections. Furthermore, we found that E. faecalis, a prevalent CAUTI pathogen, uses the secreted protease, SprE, to induce fibrin accumulation and create a niche ideal for growth, biofilm formation, and persistence during CAUTI.

Early posttraumatic brain injury tranexamic acid prevents blood-brain barrier hyperpermeability and improves surrogates of neuroclinical recovery

BACKGROUND

Tranexamic acid (TXA) given early, but not late, after traumatic brain injury (TBI) appears to improve survival. This may be partly related to TXA-driven profibrinolysis and increased leukocyte (LEU)-mediated inflammation when administered late post-injury. We hypothesized that early TXA (1 hour post-TBI), blunts penumbral, blood-brain barrier (BBB) leukocyte-endothelial cell (LEU-EC) interactions and microvascular permeability, in vivo when compared with late administration (24 hours post-TBI).

METHODS

CD1 male mice (n = 35) were randomized to severe TBI (injury by controlled cortical impact; injury: velocity, 6 m/s; depth, 1 mm; diameter, 3 mm) or sham craniotomy followed by intravenous saline (placebo) at 1 hour, or TXA (30 mg/kg) at 1 hour or 24 hours. At 48 hours, in vivo pial intravital microscopy visualized live penumbral LEU-EC interactions and BBB microvascular fluorescent albumin leakage. Neuroclinical recovery was assessed by the Garcia Neurological Test (motor, sensory, reflex, and balance assessments) and body weight loss recovery at 1 and 2 days after injury. Analysis of variance with Bonferroni correction assessed intergroup differences ( p < 0.05).

RESULTS

One-hour, but not 24-hour, TXA improved Garcia Neurological Test performance on day 1 post-TBI compared with placebo. Both 1 hour and 24 hours TXA similarly improved day 1 weight loss recovery, but only 1 hour TXA significantly improved weight loss recovery on day 2 compared with placebo ( p = 0.04). No intergroup differences were found in LEU rolling or adhesion between injured animal groups. Compared with untreated injured animals, only TXA at 1 hour reduced BBB permeability.

CONCLUSION

Only early post-TBI TXA consistently improves murine neurological recovery. Tranexamic acid preserves BBB integrity but only when administered early. This effect appears independent of LEU-EC interactions and demonstrates a time-sensitive effect that supports only early TXA administration.

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.

Semi-automated thrombin dynamics applying the ST Genesia thrombin generation assay

Background

The haemostatic balance is an equilibrium of pro- and anticoagulant factors that work synergistically to prevent bleeding and thrombosis. As thrombin is the central enzyme in the coagulation pathway, it is desirable to measure thrombin generation (TG) in order to detect possible bleeding or thrombotic phenotypes, as well as to investigate the capacity of drugs affecting the formation of thrombin. By investigating the underlying processes of TG (i.e., prothrombin conversion and inactivation), additional information is collected about the dynamics of thrombin formation.

Objectives

To obtain reference values for thrombin dynamics (TD) analysis in 112 healthy donors using an automated system for TG.

Methods

TG was measured on the ST Genesia, fibrinogen on the Start, anti-thrombin (AT) on the STA R Max and α₂Macroglobulin (α₂M) with an in-house chromogenic assay.

Results

TG was measured using STG-BleedScreen, STG-ThromboScreen and STG-DrugScreen. The TG data was used as an input for TD analysis, in combination with plasma levels of AT, α₂M and fibrinogen that were 113% (108-118%), 2.6 μM (2.2 μM-3.1 μM) and 2.9 g/L (2.6-3.2 g/L), respectively. The maximum rate of the prothrombinase complex (PCmax) and the total amount of prothrombin converted (PCtot) increased with increasing tissue factor (TF) concentration. PC_tot increased from 902 to 988 nM, whereas PC_max increased from 172 to 508 nM/min. Thrombin (T)-AT and T-α₂M complexes also increased with increasing TF concentration (i.e., from 860 to 955 nM and from 28 to 33 nm, respectively). PC_tot, T-AT and T-α₂M complex formation were strongly inhibited by addition of thrombomodulin (-44%, -43%, and -48%, respectively), whereas PC_max was affected less (-24%). PC_tot, PC_max, T-AT, and T-α₂M were higher in women using oral contraceptives (OC) compared to men/women without OC, and inhibition by thrombomodulin was also significantly less in women on OC (p < 0.05).

Conclusions

TG measured on the ST Genesia can be used as an input for TD analysis. The data obtained can be used as reference values for future clinical studies as the balance between prothrombin conversion and thrombin inactivation has shown to be useful in several clinical settings.

The Use of Tranexamic Acid in Hip and Pelvic Fracture Surgeries

Tranexamic acid (TXA) use has expanded across many surgical specialties. It has been shown to reduce blood loss, decrease transfusion rates, and, in some cases, improve mortality. Within orthopaedic surgery, its popularity has primarily grown within arthroplasty and spinal surgery. It has only recently gained traction within the field of orthopaedic trauma and fracture care. At this time, most literature focuses on hip fracture and pelvic trauma surgery. For hip fractures, the results are encouraging and generally support the claim that TXA may lower overall blood loss and decrease transfusions. Conversely, less support exists for TXA use in fractures of the acetabulum or pelvic ring. Based on the current fracture-related studies, TXA does not seem to carry an increased risk of thromboembolism or other complications. In addition, few studies have been noted discussing the route of administration, timing, or dosage. This article reviews the most current literature regarding TXA use in fracture care and expands on the need for further research to evaluate the role of TXA in orthopaedic trauma populations who carry a high risk for transfusion.