Antifibrinolytic drugs for acute traumatic injury

Tranexamic Acid Reduces the Amount of Blood Transfused in Revision Total Hip Arthroplasty for Vancouver B2/B3 Periprosthetic Femur Fractures

BACKGROUND

Periprosthetic fractures around total hip arthroplasty (THA) represent a significant source of morbidity and mortality. The use of tranexamic acid (TXA) in arthroplasty is well described, yet little literature supports its role in periprosthetic femur fractures (PFFs). This study investigated the effect of preoperative TXA administration on transfusion rate and volume, length of stay, and 90-day complication rates in patients undergoing revision THA for PFF.

MATERIALS AND METHODS

All patients undergoing revision THA for PFF (Vancouver B2/B3) at our institution from August 2016 to June 2022 were identified. Routine TXA administration at surgical start was introduced in 2018. Patient demographics, operative time, blood product use, length of stay, and 90-day complications were collected. Patients were divided into those who received TXA preoperatively and those who did not.

RESULTS

A total of 56 patients were included. There was no difference in age, sex, anesthetic type, fracture classification, or preoperative blood values between cohorts. TXA significantly lowered the amount of blood product required (2.3 units vs 3.2 units, P=.023). Preoperative TXA did not independently reduce length of stay; however, blood transfusion was associated with increased length of stay (7 days vs 4.7 days, P=.003). There were no differences in 90-day complications.

CONCLUSION

Among patients who underwent revision THA for Vancouver B2/B3 PFF, TXA did not affect transfusion rates but did result in the use of fewer blood products without an increase in complications. We support routine use of TXA in this patient population. Future studies should assess earlier administration of TXA in the emergency department or once patients' conditions have been medically optimized. [Orthopedics. 202x;4x(x):xx-xx.].

Haemostatic therapies for stroke due to acute, spontaneous intracerebral haemorrhage

BACKGROUND

Outcome after acute spontaneous (non-traumatic) intracerebral haemorrhage (ICH) is influenced by haematoma volume. ICH expansion occurs in about 20% of people with acute ICH. Early haemostatic therapy might improve outcome by limiting ICH expansion. This is an update of a Cochrane Review first published in 2006, and last updated in 2018.

OBJECTIVES

To examine 1. the effects of individual classes of haemostatic therapies, compared with placebo or open control, in adults with acute spontaneous ICH, and 2. the effects of each class of haemostatic therapy according to the use and type of antithrombotic drug before ICH onset.

SEARCH METHODS

We searched the Cochrane Stroke Trials Register, CENTRAL (2022, Issue 8), MEDLINE Ovid, and Embase Ovid on 12 September 2022. To identify further published, ongoing, and unpublished randomised controlled trials (RCTs), we scanned bibliographies of relevant articles and searched international registers of RCTs in September 2022.

SELECTION CRITERIA

We included RCTs of any haemostatic intervention (i.e. procoagulant treatments such as clotting factor concentrates, antifibrinolytic drugs, platelet transfusion, or agents to reverse the action of antithrombotic drugs) for acute spontaneous ICH, compared with placebo, open control, or an active comparator.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcome was death/dependence (modified Rankin Scale (mRS) 4 to 6) by day 90. Secondary outcomes were ICH expansion on brain imaging after 24 hours, all serious adverse events, thromboembolic adverse events, death from any cause, quality of life, mood, cognitive function, Barthel Index score, and death or dependence measured on the Extended Glasgow Outcome Scale by day 90.

MAIN RESULTS

We included 20 RCTs involving 4652 participants: nine RCTs of recombinant activated factor VII (rFVIIa) versus placebo/open control (1549 participants), eight RCTs of antifibrinolytic drugs versus placebo/open control (2866 participants), one RCT of platelet transfusion versus open control (190 participants), and two RCTs of prothrombin complex concentrates (PCC) versus fresh frozen plasma (FFP) (47 participants). Four (20%) RCTs were at low risk of bias in all criteria. For rFVIIa versus placebo/open control for spontaneous ICH with or without surgery there was little to no difference in death/dependence by day 90 (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.74 to 1.05; 7 RCTs, 1454 participants; low-certainty evidence). We found little to no difference in ICH expansion between groups (RR 0.81, 95% CI 0.56 to 1.16; 4 RCTs, 220 participants; low-certainty evidence). There was little to no difference in all serious adverse events and death from any cause between groups (all serious adverse events: RR 0.81, 95% CI 0.30 to 2.22; 2 RCTs, 87 participants; very low-certainty evidence; death from any cause: RR 0.78, 95% CI 0.56 to 1.08; 8 RCTs, 1544 participants; moderate-certainty evidence). For antifibrinolytic drugs versus placebo/open control for spontaneous ICH, there was no difference in death/dependence by day 90 (RR 1.00, 95% CI 0.93 to 1.07; 5 RCTs, 2683 participants; high-certainty evidence). We found a slight reduction in ICH expansion with antifibrinolytic drugs for spontaneous ICH compared to placebo/open control (RR 0.86, 95% CI 0.76 to 0.96; 8 RCTs, 2866 participants; high-certainty evidence). There was little to no difference in all serious adverse events and death from any cause between groups (all serious adverse events: RR 1.02, 95% CI 0.75 to 1.39; 4 RCTs, 2599 participants; high-certainty evidence; death from any cause: RR 1.02, 95% CI 0.89 to 1.18; 8 RCTs, 2866 participants; high-certainty evidence). There was little to no difference in quality of life, mood, or cognitive function (quality of life: mean difference (MD) 0, 95% CI -0.03 to 0.03; 2 RCTs, 2349 participants; mood: MD 0.30, 95% CI -1.98 to 2.57; 2 RCTs, 2349 participants; cognitive function: MD -0.37, 95% CI -1.40 to 0.66; 1 RCTs, 2325 participants; all high-certainty evidence). Platelet transfusion likely increases death/dependence by day 90 compared to open control for antiplatelet-associated ICH (RR 1.29, 95% CI 1.04 to 1.61; 1 RCT, 190 participants; moderate-certainty evidence). We found little to no difference in ICH expansion between groups (RR 1.32, 95% CI 0.91 to 1.92; 1 RCT, 153 participants; moderate-certainty evidence). There was little to no difference in all serious adverse events and death from any cause between groups (all serious adverse events: RR 1.46, 95% CI 0.98 to 2.16; 1 RCT, 190 participants; death from any cause: RR 1.42, 95% CI 0.88 to 2.28; 1 RCT, 190 participants; both moderate-certainty evidence). For PCC versus FFP for anticoagulant-associated ICH, the evidence was very uncertain about the effect on death/dependence by day 90, ICH expansion, all serious adverse events, and death from any cause between groups (death/dependence by day 90: RR 1.21, 95% CI 0.76 to 1.90; 1 RCT, 37 participants; ICH expansion: RR 0.54, 95% CI 0.23 to 1.22; 1 RCT, 36 participants; all serious adverse events: RR 0.27, 95% CI 0.02 to 3.74; 1 RCT, 5 participants; death from any cause: RR 0.49, 95% CI 0.16 to 1.56; 2 RCTs, 42 participants; all very low-certainty evidence).

AUTHORS' CONCLUSIONS

In this updated Cochrane Review including 20 RCTs involving 4652 participants, rFVIIa likely results in little to no difference in reducing death or dependence after spontaneous ICH with or without surgery; antifibrinolytic drugs result in little to no difference in reducing death or dependence after spontaneous ICH, but result in a slight reduction in ICH expansion within 24 hours; platelet transfusion likely increases death or dependence after antiplatelet-associated ICH; and the evidence is very uncertain about the effect of PCC compared to FFP on death or dependence after anticoagulant-associated ICH. Thirteen RCTs are ongoing and are likely to increase the certainty of the estimates of treatment effect.

Venous thromboembolism in orthopedic surgery: Global guidelines

Venous thromboembolism (VTE) is a severe complication that can occur after major orthopedic procedures. As VTE-related morbidity and mortality are a significant concern for both medical professionals and patients, and preventative measures are typically employed. Multiple organizations, including the American College of Chest Physicians (ACCP) and the American Academy of Orthopedic Surgeons (AAOS), have developed guidelines for VTE prophylaxis specifically in patients undergoing joint replacement procedures. However, recently, the International Consensus Meeting (ICM) was convened, which brought together over 600 experts from 68 countries and 135 international societies. These experts, spanning a range of medical disciplines including orthopedic surgery, anesthesia, cardiology, hematology, vascular, and internal medicine, conducted a comprehensive review of the literature using a strict Delphi process to generate practical recommendations for VTE prophylaxis across all types of orthopedic procedures. This review article summarizes some of the recommendations of the ICM.

Drugs to reduce bleeding and transfusion in major open vascular or endovascular surgery: a systematic review and network meta-analysis

BACKGROUND

Vascular surgery may be followed by internal bleeding due to inadequate surgical haemostasis, abnormal clotting, or surgical complications. Bleeding ranges from minor, with no transfusion requirement, to massive, requiring multiple blood product transfusions. There are a number of drugs, given systemically or applied locally, which may reduce the need for blood transfusion.

OBJECTIVES

To assess the effectiveness and safety of anti-fibrinolytic and haemostatic drugs and agents in reducing bleeding and the need for blood transfusion in people undergoing major vascular surgery or vascular procedures with a risk of moderate or severe (> 500 mL) blood loss.

SEARCH METHODS

We searched: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL, and Transfusion Evidence Library. We also searched the WHO ICTRP and ClinicalTrials.gov trial registries for ongoing and unpublished trials. Searches used a combination of MeSH and free text terms from database inception to 31 March 2022, without restriction on language or publication status.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in adults of drug treatments to reduce bleeding due to major vascular surgery or vascular procedures with a risk of moderate or severe blood loss, which used placebo, usual care or another drug regimen as control.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were units of red cells transfused and all-cause mortality. Our secondary outcomes included risk of receiving an allogeneic blood product, risk of reoperation or repeat procedure due to bleeding, risk of a thromboembolic event, risk of a serious adverse event and length of hospital stay. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included 22 RCTs with 3393 participants analysed, of which one RCT with 69 participants was reported only in abstract form, with no usable data. Seven RCTs evaluated systemic drug treatments (three aprotinin, two desmopressin, two tranexamic acid) and 15 RCTs evaluated topical drug treatments (drug-containing bioabsorbable dressings or glues), including fibrin, thrombin, collagen, gelatin, synthetic sealants and one investigational new agent. Most trials were conducted in high-income countries and the majority of the trials only included participants undergoing elective surgery. We also identified two ongoing RCTs. We were unable to perform the planned network meta-analysis due to the sparse reporting of outcomes relevant to this review. Systemic drug treatments We identified seven trials of three systemic drugs: aprotinin, desmopressin and tranexamic acid, all with placebo controls. The trials of aprotinin and desmopressin were small with very low-certainty evidence for all of our outcomes. Tranexamic acid versus placebo was the systemic drug comparison with the largest number of participants (2 trials; 1460 participants), both at low risk of bias. The largest of these included a total of 9535 individuals undergoing a number of different higher risk surgeries and reported limited information on the vascular subgroup (1399 participants). Neither trial reported the number of units of red cells transfused per participant up to 30 days. Three outcomes were associated with very low-certainty evidence due to the very wide confidence intervals (CIs) resulting from small study sizes and low number of events. These were: all-cause mortality up to 30 days; number of participants requiring an allogeneic blood transfusion up to 30 days; and risk of requiring a repeat procedure or operation due to bleeding. Tranexamic acid may have no effect on the risk of thromboembolic events up to 30 days (risk ratio (RR) 1.10, 95% CI 0.88 to 1.36; 1 trial, 1360 participants; low-certainty evidence due to imprecision). There is one large ongoing trial (8320 participants) comparing tranexamic acid versus placebo in people undergoing non-cardiac surgery who are at high risk of requiring a red cell transfusion. This aims to complete recruitment in April 2023. This trial has primary outcomes of proportion of participants transfused with red blood cells and incidence of venous thromboembolism (DVT or PE). Topical drug treatments Most trials of topical drug treatments were at high risk of bias due to their open-label design (compared with usual care, or liquids were compared with sponges). All of the trials were small, most were very small, and few reported clinically relevant outcomes in the postoperative period. Fibrin sealant versus usual care was the topical drug comparison with the largest number of participants (5 trials, 784 participants). The five trials that compared fibrin sealant with usual care were all at high risk of bias, due to the open-label trial design with no measures put in place to minimise reporting bias. All of the trials were funded by pharmaceutical companies. None of the five trials reported the number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. The other three outcomes were associated with very low-certainty evidence with wide confidence intervals due to small sample sizes and the low number of events, these were: all-cause mortality up to 30 days; risk of requiring a repeat procedure due to bleeding; and risk of thromboembolic disease up to 30 days. We identified one large trial (500 participants) comparing fibrin sealant versus usual care in participants undergoing abdominal aortic aneurysm repair, which has not yet started recruitment. This trial lists death due to arterial disease and reintervention rates as primary outcomes.

AUTHORS' CONCLUSIONS

Because of a lack of data, we are uncertain whether any systemic or topical treatments used to reduce bleeding due to major vascular surgery have an effect on: all-cause mortality up to 30 days; risk of requiring a repeat procedure or operation due to bleeding; number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. There may be no effect of tranexamic acid on the risk of thromboembolic events up to 30 days, this is important as there has been concern that this risk may be increased. Trials with sample size targets of thousands of participants and clinically relevant outcomes are needed, and we look forward to seeing the results of the ongoing trials in the future.

Retrospective analysis of tranexamic acid administration in French war-wounded between October 2016 and September 2020

INTRODUCTION

Since 2013, the French Army Health Service, in agreement with international experts, has recommended the administration of 1 g of tranexamic acid (TXA) in trauma patients in haemorrhagic shock or at risk of bleeding within 3 hours of the trauma.

METHODS

The aim of this analysis was to describe the administration of TXA in French military personnel wounded during military operations in the Sahelo-Sahelian band between October 2016 and September 2020. Data were collected from forward health records and hospital data from the French hospital where the casualty was finally evacuated. Underuse of TXA was defined as the lack of administration in casualties who had received a blood transfusion with one or more of red blood cells, low-titre whole blood or French lyophilised plasma within the first 24 hours of injury and overuse as its administration in the non-transfused casualty.

RESULTS

Of the 76 patients included, 75 were men with an average age of 28 years. Five patients died during their management. 19 patients received TXA (25%) and 16 patients were transfused (21%). Underuse of TXA occurred in 3 of the 16 patients (18.8%) transfused. Overuse occurred in 6 of 60 (10%) non-transfused patients.

CONCLUSION

The analysis found an important underuse of TXA (almost 20%) and highlighted the need for optimising the prehospital clinical practice guidelines to aid prehospital medical practitioners more accurately in administering TXA to casualties that will require blood products.

Systemic hemostatic agents initiated in trauma patients in the pre-hospital setting: a systematic review

Purpose

The effect of systemic hemostatic agents initiated during pre-hospital care of severely injured patients with ongoing bleeding or traumatic brain injury (TBI) remains controversial. A systematic review and meta-analysis was therefore conducted to assess the effectiveness and safety of systemic hemostatic agents as an adjunctive therapy in people with major trauma and hemorrhage or TBI in the context of developing the Italian National Institute of Health guidelines on major trauma integrated management.

Methods

PubMed, Embase, and Cochrane Library databases were searched up to October 2021 for studies that investigated pre-hospital initiated treatment with systemic hemostatic agents. The certainty of evidence was evaluated with the Grading of Recommendations Assessment, Development, and Evaluation approach, and the quality of each study was determined with the Cochrane risk-of-bias tool. The primary outcome was overall mortality, and secondary outcomes included cause-specific mortality, health-related quality of life, any adverse effects and blood product use, hemorrhage expansion, and patient-reported outcomes.

Results

Five trials of tranexamic acid (TXA) met the inclusion criteria for this meta-analysis. With a high certainty of evidence, when compared to placebo TXA reduced mortality at 24 h (relative risk = 0.83, 95% confidence interval = 0.73–0.94) and at 1 month among trauma patients (0.91, 0.85–0.97). These results depend on the subgroup of patients with significant hemorrhage because in the subgroup of TBI there are no difference between TXA and placebo. TXA also reduced bleeding death and multiple organ failure whereas no difference in health-related quality of life.

Conclusion

Balancing benefits and harms, TXA initiated in the pre-hospital setting can be used for patients experiencing major trauma with significant hemorrhage since it reduces the risk of mortality at 24 h and one month with no difference in terms of adverse effects when compared to placebo. Considering the subgroup of severe TBI, no difference in mortality rate was found at 24 h and one month. These results highlight the need to conduct future studies to investigate the role of other systemic hemostatic agents in the pre-hospital settings.

Hyperfibrinolysis and fibrinolysis shutdown in patients with traumatic brain injury

Traumatic brain injury (TBI) is associated with coagulation/fibrinolysis disorders. We retrospectively evaluated 61 TBI cases transported to hospital within 1 h post-injury. Levels of thrombin-antithrombin III complex (TAT), D-dimer, and plasminogen activator inhibitor-1 (PAI-1) were measured on arrival and 3 h, 6 h, 12 h, 1 day, 3 days and 7 days after injury. Multivariate logistic regression analysis was performed to identify prognostic factors for coagulation and fibrinolysis. Plasma TAT levels peaked at admission and decreased until 1 day after injury. Plasma D-dimer levels increased, peaking up to 3 h after injury, and decreasing up to 3 days after injury. Plasma PAI-1 levels increased up to 3 h after injury, the upward trend continuing until 6 h after injury, followed by a decrease until 3 days after injury. TAT, D-dimer, and PAI-1 were elevated in the acute phase of TBI in cases with poor outcome. Multivariate logistic regression analysis showed that D-dimer elevation from admission to 3 h after injury and PAI-1 elevation from 6 h to 1 day after injury were significant negative prognostic indicators. Post-TBI hypercoagulation, fibrinolysis, and fibrinolysis shutdown were activated consecutively. Hyperfibrinolysis immediately after injury and subsequent fibrinolysis shutdown were associated with poor outcome.

Tranexamic Acid in Foot and Ankle Surgery: A Topical Review and Value Analysis

Tranexamic acid (TXA) has become a commonly used perioperative intervention in total joint arthroplasty, shoulder and knee arthroscopy, and spinal procedures in order to minimize blood loss, hematoma formation, hemarthrosis, and wound healing complications. There is a potential role for TXA use in foot and ankle procedures, with limited studies suggesting a potential benefit in minimizing postoperative wound complications and blood loss without an increased risk of thromboembolic events. In light of the profound clinical and financial impact of TXA use in other orthopaedic subspecialties and the early successes in foot and ankle surgery, we aim to provide more information about TXA and its use in foot and ankle surgery. Therefore, the purpose of this review is to perform a comprehensive literature review on the topic of TXA use in foot and ankle procedures in order to describe the pertinent available literature on the use of TXA in orthopaedic surgery and its implications specifically in foot and ankle surgery. It is our aim to identify potential benefits and shortcomings in the available evidence on TXA use for foot and ankle surgery in hopes to (1) best inform foot and ankle surgeons where beneficial and safe and (2) inspire further research on this topic as it relates to clinical management for foot and ankle patients.Levels of Evidence: Level IV.

Tranexamic Acid for Postpartum Hemorrhage Treatment in Low-Resource Settings: A Rapid Scoping Review

Tranexamic acid (TXA) effectively reduces bleeding in women with postpartum hemorrhage (PPH) in hospital settings. To guide policies and practices, this rapid scoping review undertaken by two reviewers aimed to examine how TXA is utilized in lower-level maternity care settings in low-resource settings. Articles were searched in EMBASE, MEDLINE, Emcare, the Maternity and Infant Care Database, the Joanna Briggs Institute Evidence-Based Practice Database, and the Cochrane Library from January 2011 to September 2021. We included non-randomized and randomized research looking at the feasibility, acceptability, and health system implications in low- and lower-middle-income countries. Relevant information was retrieved using pre-tested forms. Findings were descriptively synthesized. Out of 129 identified citations, 23 records were eligible for inclusion, including 20 TXA effectiveness studies, two economic evaluations, and one mortality modeling. Except for the latter, all the studies were conducted in lower-middle-income countries and most occurred in tertiary referral hospitals. When compared to placebo or other medications, TXA was found effective in both treating and preventing PPH during vaginal and cesarean delivery. If made available in home and clinic settings, it can reduce PPH-related mortality. TXA could be cost-effective when used with non-surgical interventions to treat refractory PPH. Capacity building of service providers appears to need time-intensive training and supportive monitoring. No studies were exploring TXA acceptability from the standpoint of providers, as well as the implications for health governance and information systems. There is a scarcity of information on how to prepare the health system and services to incorporate TXA in lower-level maternity care facilities in low-resource settings. Implementation research is critically needed to assist practitioners and decision-makers in establishing a TXA-inclusive PPH treatment package to reduce PPH-related death and disability.

Coagulopathy and Traumatic Brain Injury: Overview of New Diagnostic and Therapeutic Strategies

Coagulopathy is a common sequela of traumatic brain injury. Consumptive coagulopathy and secondary hyperfibrinolysis are associated with hypercoagulability. In addition, fibrinolytic pathways are hyperactivated as a result of vascular endothelial cell damage in the injured brain. Coagulation and fibrinolytic parameters change dynamically to reflect these pathologies. Fibrinogen is consumed and degraded after injury, with fibrinogen concentrations at their lowest 3-6 h after injury. Hypercoagulability causes increased fibrinolytic activity, and plasma levels of D-dimer increase immediately after traumatic brain injury, reaching a maximum at 3 h. Owing to disseminated intravascular coagulation in the presence of fibrinolysis, the bleeding tendency is highest within the first 3 h after injury, and often a condition called “talk and deteriorate” occurs. In neurointensive care, it is necessary to measure coagulation and fibrinolytic parameters such as fibrinogen and D-dimer routinely to predict and prevent the development of coagulopathy and its negative outcomes. Currently, the only evidence-based treatment for traumatic brain injury with coagulopathy is tranexamic acid in the subset of patients with mild-to-moderate traumatic brain injury. Coagulation and fibrinolytic parameters should be closely monitored, and treatment should be considered on a patient-by-patient basis.

Effect of tranexamic acid on the prognosis of patients with traumatic brain injury undergoing craniotomy: study protocol for a randomised controlled trial

INTRODUCTION

Abnormal coagulation function aggravates the prognosis of patients with traumatic brain injury (TBI). It was reported that the antifibrinolytic drug tranexamic acid (TXA) could reduce intracranial haemorrhage and mortality in non-operative patients with TBI. However, there is a lack of evaluation of TXA in patients with TBI undergoing craniotomy.

METHODS AND ANALYSIS

This is a single-centre randomised controlled, double-blind, parallel study aiming to investigate the effectiveness and safety of TXA in patients with TBI during the perioperative period. Blood loss and transfusion, neurological function, adverse events, mortality and serum immune-inflammatory cytokines will be collected and analysed.

ETHICS AND DISSEMINATION

Ethical approval has been granted by the Medical Ethics Committee of Beijing Tian Tan Hospital, Capital Medical University (reference number KY 2020-136-03). The results of this study will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2100041911.

Tranexamic acid in otorhinolaryngology - A contemporary review

Tranexamic acid (TXA) is an anti-fibrinolytic agent which has been proven beneficial in multiple surgical specialties where significant bleeding can occur. Whilst it has been widely available for over 40 years its use within Otorhinolaryngology is still limited. Operations in Otorhinolaryngology are particularly varied with some such as tonsillectomy having the potential for significant life threatening bleeding. Other operations are performed within small confined surgical fields and even small amounts of bleeding can significantly detriment surgical field and increase technical difficulty and operative time. This review evaluated the current literature on the benefits of tranexamic acid within the field of Otorhinolaryngology and Head and Neck Surgery. Overall TXA was demonstrated to be a safe drug with no major adverse effects including thromboembolic events reported in any study. It has been shown to be of particular benefit in rhinology by improving surgical field, reducing operative time and reducing postoperative swelling and ecchymosis. The benefit in tonsillectomy is less clear and further studies are required to evaluate its potential use in the reduction of post tonsillectomy haemorrhage rates.

Bleeding Disorders in Primary Fibrinolysis

Fibrinolysis is a complex enzymatic process aimed at dissolving blood clots to prevent vascular occlusions. The fibrinolytic system is composed of a number of cofactors that, by regulating fibrin degradation, maintain the hemostatic balance. A dysregulation of fibrinolysis is associated with various pathological processes that result, depending on the type of abnormality, in prothrombotic or hemorrhagic states. This narrative review is focused on the congenital and acquired disorders of primary fibrinolysis in both adults and children characterized by a hyperfibrinolytic state with a bleeding phenotype.

Association of Low-Dose Whole-Body Computed Tomography With Missed Injury Diagnoses and Radiation Exposure in Patients With Blunt Multiple Trauma

Question

Is low-dose whole-body computed tomography with statistical image reconstruction associated with similar rates of missed injuries and accuracy but reduced radiation exposure compared with standard-dose whole-body computed tomography in the primary diagnostic workup of blunt multiple trauma?

Findings

In this quasi-experimental cohort study of 971 patients with suspected blunt multiple trauma, participants in the standard-dose and low-dose whole-body computed tomography groups had the same risk of missed injury diagnoses. Low-dose scanning markedly reduced exposure to radiation, improved the contrast-to-noise ratio, and showed similar diagnostic accuracy among the investigated anatomical areas and organs when compared with standard-dose scanning.

Meaning

These findings suggest that low-dose whole-body computed tomography may safely replace standard-dose scanning in the primary diagnostic workup of blunt multiple trauma.

Importance

Initial whole-body computed tomography (WBCT) for screening patients with suspected blunt multiple trauma remains controversial and a source of excess radiation exposure.

Objective

To determine whether low-dose WBCT scanning using an iterative reconstruction algorithm does not increase the rate of missed injury diagnoses at the point of care compared with standard-dose WBCT with the benefit of less radiation exposure.

Design, Setting, and Participants

This quasi-experimental, prospective time-series cohort study recruited 1074 consecutive patients admitted for suspected blunt multiple trauma to an academic metropolitan trauma center in Germany from September 3, 2014, through July 26, 2015, for the standard-dose protocol, and from August 7, 2015, through August 20, 2016, for the low-dose protocol. Five hundred sixty-five patients with suspected blunt multiple trauma prospectively received standard-dose WBCT, followed by 509 patients who underwent low-dose WBCT. Confounding was controlled by segmented regression analysis and a secondary multivariate logistic regression model. Data were analyzed from January 16, 2017, through October 14, 2019.

Interventions

Standard- or low-dose WBCT.

Main Outcomes and Measures

The primary outcome was the incidence of missed injury diagnoses at the point of care, using a synopsis of clinical, surgical, and radiological findings as an independent reference test. The secondary outcome was radiation exposure with either imaging strategy.

Results

Of 1074 eligible patients, 971 (mean [SD] age, 52.7 [19.5] years; 649 men [66.8%]) completed the study. A total of 114 patients (11.7%) had multiple trauma, as defined by an Injury Severity Score of 16 or greater. The proportion of patients with any missed injury diagnosis at the point of care was 109 of 468 (23.3%) in the standard-dose and 107 of 503 (21.3%) in the low-dose WBCT groups (risk difference, −2.0% [95% CI, −7.3% to 3.2%]; unadjusted odds ratio, 0.89 [95% CI, 0.66-1.20]; P = .45). Adjustments for autocorrelation and multiple confounding variables did not alter the results. Radiation exposure, measured by the volume computed tomography dose index, was lowered from a median of 11.7 (interquartile range, 11.7-17.6) mGy in the standard-dose WBCT group to 5.9 (interquartile range, 5.9-8.8) mGy in the low-dose WBCT group (P < .001).

Conclusions and Relevance

Low-dose WBCT using iterative image reconstruction does not appear to increase the risk of missed injury diagnoses at the point of care compared with standard-dose protocols while almost halving the exposure to diagnostic radiation.

Enhanced Antifibrinolytic Efficacy of a Plasmin-Specific Kunitz-Inhibitor (60-Residue Y11T/L17R with C-Terminal IEK) of Human Tissue Factor Pathway Inhibitor Type-2 Domain1

Current antifibrinolytic agents reduce blood loss by inhibiting plasmin active sites (e.g., aprotinin) or by preventing plasminogen/tissue plasminogen activator (tPA) binding to fibrin clots (e.g., ε-aminocaproic acid and tranexamic acid); however, they have adverse side effects. Here, we expressed 60-residue (NH2NAE…IEKCOOH) Kunitz domain1 (KD1) mutants of human tissue factor pathway inhibitor type-2 that inhibit plasmin as well as plasminogen activation. A single (KD1-L17R-KCOOH) and a double mutant (KD1-Y11T/L17R- KCOOH) were expressed in Escherichia coli as His-tagged constructs, each with enterokinase cleavage sites. KD1-Y11T/L17R-KCOOH was also expressed in Pichia pastoris. KD1-Y11T/L17R-KCOOH inhibited plasmin comparably to aprotinin and bound to the kringle domains of plasminogen/plasmin and tPA with Kd of ~50 nM and ~35 nM, respectively. Importantly, compared to aprotinin, KD1-L17R-KCOOH and KD1-Y11T/L17R-KCOOH did not inhibit kallikrein. Moreover, the antifibrinolytic potential of KD1-Y11T/L17R-KCOOH was better than that of KD1-L17R-KCOOH and similar to that of aprotinin in plasma clot-lysis assays. In thromboelastography experiments, KD1-Y11T/L17R-KCOOH was shown to inhibit fibrinolysis in a dose dependent manner and was comparable to aprotinin at a higher concentration. Further, KD1-Y11T/L17R-KCOOH did not induce cytotoxicity in primary human endothelial cells or fibroblasts. We conclude that KD1-Y11T/L17R-KCOOH is comparable to aprotinin, the most potent known inhibitor of plasmin and can be produced in large amounts using Pichia.

Efficacy and safety of tranexamic acid administration in traumatic brain injury patients: a systematic review and meta-analysis

Background

The exacerbation of intracranial bleeding is critical in traumatic brain injury (TBI) patients. Tranexamic acid (TXA) has been used to improve outcomes in TBI patient. However, the effectiveness of TXA treatment remains unclear. This study aimed to assess the effect of administration of TXA on clinical outcomes in patients with TBI by systematically reviewing the literature and synthesizing evidence of randomized controlled trials (RCTs).

Methods

MEDLINE, the Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi (ICHUSHI) Web were searched. Selection criteria included randomized controlled trials with clinical outcomes of adult TBI patients administered TXA or placebo within 24 h after admission. Two investigators independently screened citations and conducted data extraction. The primary “critical” outcome was all-cause mortality. The secondary “important” outcomes were good neurological outcome rates, enlargement of bleeding, incidence of ischemia, and hemorrhagic intracranial complications. Random effect estimators with weights calculated by the inverse variance method were used to report risk ratios (RRs).

Results

A total of 640 records were screened. Seven studies were included for quantitative analysis. Of 10,044 patients from seven of the included studies, 5076 were randomly assigned to the TXA treatment group, and 4968 were assigned to placebo. In the TXA treatment group, 914 patients (18.0%) died, while 961 patients (19.3%) died in the placebo group. There was no significant difference between groups (RR, 0.93; 95% confidence interval, 0.86–1.01). No significant differences between the groups in other important outcomes were also observed.

Conclusions

TXA treatment demonstrated a tendency to reduce head trauma-related deaths in the TBI population, with no significant incidence of thromboembolic events. TXA treatment may therefore be suggested in the initial TBI care.

The never ending success story of tranexamic acid in acquired bleeding

Tranexamic acid (TXA) is an anti-fibrinolytic agent that acts by inhibiting plasminogen activation and fibrinolysis. Although its first clinical use dates back more than 50 years, this hemostatic agent is still the object of intense clinical and developmental research. In particular, renewed interest in TXA has arisen following evidence that it has a beneficial effect in reducing blood loss in a variety of medical and surgical conditions at increased risk of bleeding. Given this characteristic, TXA is currently considered a mainstay of Patient Blood Management programs aimed at reducing patients’ exposure to allogeneic blood transfusion. Importantly, recent large randomized controlled trials have consistently documented that the use of TXA confers a survival advantage in a number of globally critical clinical conditions associated with acute bleeding, including traumatic injury and post-partum hemorrhage, without increasing the thromboembolic risk.

Pericardial Tamponade After Systemic Alteplase in Stroke and Emergent Reversal With Tranexamic Acid

Alteplase, or tissue plasminogen activator (tPA), lyses clots by enhancing activation of plasminogen to plasmin. Conversely, tranexamic acid (TXA) functions by inhibiting the conversion of plasminogen to plasmin, which inhibits fibrinolysis. TXA has proven safe and effective in major bleeding with various etiologies. A 76-year-old male developed acute ischemic stroke symptoms. Systemic alteplase was administered and he showed clinical improvement. Shortly thereafter, the patient became hypotensive and lost pulses. Point-of-care ultrasound revealed cardiac tamponade. TXA was immediately given to inhibit fibrinolysis since cryoprecipitate and blood products were not immediately available. Pericardiocentesis was performed and successfully removed 200 milliliters of blood with return of pulses. Clinicians must consider TXA as a rapidly accessible antagonist of tPA’s fibrinolytic effects.

The many roles of tranexamic acid: An overview of the clinical indications for TXA in medical and surgical patients

Clinically significant bleeding can occur as a consequence of surgery, trauma, obstetric complications, anticoagulation, and a wide variety of disorders of hemostasis. As the causes of bleeding are diverse and not always immediately apparent, the availability of a safe, effective, and non-specific hemostatic agent is vital in a wide range of clinical settings, with antifibrinolytic agents often utilized for this purpose. Tranexamic acid (TXA) is one of the most commonly used and widely researched antifibrinolytic agents; its role in postpartum hemorrhage, menorrhagia, trauma-associated hemorrhage, and surgical bleeding has been well defined. However, the utility of TXA goes beyond these common indications, with accumulating data suggesting its ability to reduce bleeding and improve clinical outcomes in the face of many different hemostatic challenges, without a clear increase in thrombotic risk. Herein, we review the literature and provide practical suggestions for clinical use of TXA across a broad spectrum of bleeding disorders.

The effectiveness and safety of anti-fibrinolytics in patients with acute intracranial haemorrhage: statistical analysis plan for an individual patient data meta-analysis

Abstract

Introduction: The Anti-fibrinolytics Trialists Collaboration aims to increase knowledge about the effectiveness and safety of anti-fibrinolytic treatment by conducting individual patient data (IPD) meta-analyses of randomised trials. This article presents the statistical analysis plan for an IPD meta-analysis of the effects of anti-fibrinolytics for acute intracranial haemorrhage.

Methods: The protocol for the IPD meta-analysis has been registered with PROSPERO (CRD42019128260). We will conduct an individual patient data meta-analysis of randomised controlled trials with 500 patients or more assessing the effects of anti-fibrinolytics in acute intracranial haemorrhage. The primary outcomes will be 1) death from stroke or head injury within 30 days of randomisation, and 2) death from stroke or head injury, or dependency within 90 days of randomisation. The primary outcomes will be limited to patients treated within three hours of injury or stroke onset. We will report treatment effects using odds ratios and 95% confidence intervals. We use logistic regression models to examine how the effect of anti-fibrinolytics vary by time to treatment, severity of intracranial bleeding, and age. We will also examine the effect of anti-fibrinolytics on secondary outcomes including death, dependency, vascular occlusive events, seizures, and neurological outcomes. Secondary outcomes will be assessed in all patients irrespective of time of treatment. All analyses will be conducted on an intention-to-treat basis.

Conclusions: This IPD meta-analysis will examine important clinical questions about the effects of anti-fibrinolytic treatment in patients with intracranial haemorrhage that cannot be answered using aggregate data. With IPD we can examine how effects vary by time to treatment, bleeding severity, and age, to gain better understanding of the balance of benefit and harms on which to base recommendations for practice.

The effectiveness and safety of anti-fibrinolytics in patients with acute intracranial haemorrhage: statistical analysis plan for an individual patient data meta-analysis

INTRODUCTION

The Anti-fibrinolytics Trialists Collaboration aims to increase knowledge about the effectiveness and safety of anti-fibrinolytic treatment by conducting individual patient data (IPD) meta-analyses of randomised trials. This article presents the statistical analysis plan for an IPD meta-analysis of the effects of anti-fibrinolytics for acute intracranial haemorrhage.

METHODS

The protocol for the IPD meta-analysis has been registered with PROSPERO (CRD42019128260). We will conduct an individual patient data meta-analysis of randomised controlled trials with 500 patients or more assessing the effects of anti-fibrinolytics in acute intracranial haemorrhage. The primary outcomes will be 1) death from stroke or head injury within 30 days of randomisation, and 2) death from stroke or head injury, or dependency within 90 days of randomisation. The primary outcomes will be limited to patients treated within three hours of injury or stroke onset. We will report treatment effects using odds ratios and 95% confidence intervals. We use logistic regression models to examine how the effect of anti-fibrinolytics vary by time to treatment, severity of intracranial bleeding, and age. We will also examine the effect of anti-fibrinolytics on secondary outcomes including death, dependency, vascular occlusive events, seizures, and neurological outcomes. Secondary outcomes will be assessed in all patients irrespective of time of treatment. All analyses will be conducted on an intention-to-treat basis.

CONCLUSIONS

This IPD meta-analysis will examine important clinical questions about the effects of anti-fibrinolytic treatment in patients with intracranial haemorrhage that cannot be answered using aggregate data. With IPD we can examine how effects vary by time to treatment, bleeding severity, and age, to gain better understanding of the balance of benefit and harms on which to base recommendations for practice.

Safety of intravenous tranexamic acid in patients undergoing majororthopaedic surgery: a meta-analysis of randomised controlled trials

Among the various pharmacological options to decrease peri-operative bleeding, tranexamic acid appears to be one of the most interesting. Several trials have consistently documented the efficacy of this synthetic drug in reducing the risk of blood loss and the need for allogeneic blood transfusion in patients undergoing total hip and knee arthroplasty. The safety of intravenous tranexamic acid in major orthopaedic surgery, particularly regarding the risk of venous thromboembolism, was systematically analysed in this review. A systematic search of the literature identified 73 randomised controlled trials involving 4,174 patients and 2,779 controls. The raw overall incidence of venous thromboembolism was 2.1% in patients who received intravenous tranexamic acid and 2.0% in controls. A meta-analytic pooling showed that the risk of venous thromboembolism in tranexamic acid-treated patients was not significantly different from that of controls (risk difference: 0.01%, 95% confidence interval [CI]: -0.05%, 0.07%; risk ratio: 1.067, 95% CI: 0.760-1.496). Other severe drug-related adverse events occurred very rarely (0.1%). In conclusion, the results of this systematic review and meta-analysis show that intravenous tranexamic acid is a safe pharmacological treatment to reduce blood loss and transfusion requirements in patients undergoing major orthopaedic surgery.

Fibrinogen for the management of critical obstetric hemorrhage

AIM

In cases of critical obstetric hemorrhage leading to extreme hypofibrinogenemia, fibrinogen is the marker that indicates the critical severity, and early fibrinogen supplementation centering on hemostatic resuscitation is a vital treatment to stabilize a catastrophic condition. In this review, we investigated the effect of fibrinogen level on hemostasis and what we can do to treat hypofibrinogenemia efficiently and improve patients' outcome.

METHODS

We reviewed numerous articles related to hypofibrinogenemia in critical obstetric hemorrhage. Especially, we performed a systematic review on target value of fibrinogen for hemostasis and effectiveness of fibrinogen concentrate. We also reviewed the articles about the methods for early normalization of fibrinogen level such as tranexamic acid, massive transfusion protocol, and point-of-care testing.

RESULTS

The target value of fibrinogen calculated by needs for massive transfusion was 200 mg/dL or 10 mm of A5_FIBTEM . Although fibrinogen concentrate worked poorly on fibrinogen levels within the normal range, it improved the blood fibrinogen levels rapidly when it was administered to critical obstetric hemorrhage patients with serious hypofibrinogenemia. Hence, the volume of FFP transfused could be reduced along with a reduction in the frequency of pulmonary edema due to volume overload.

CONCLUSION

The patient group for which fibrinogen concentrate works most effectively is cases with severe hypofibrinogenemia. Further research is required in the light of evidence. The essence of the transfusion algorithm in critical obstetric hemorrhage is to approach the target value for obtaining hemostasis, ensure an accurate and prompt grasp of the severity using point-of-care testing, introduce a massive transfusion protocol and use tranexamic acid.

Efficacy and tolerance of early administration of tranexamic acid in patients with cirrhosis presenting with acute upper gastrointestinal bleeding: a study protocol for a multicentre, randomised, double-blind, placebo-controlled trial (the EXARHOSE study)

INTRODUCTION

The management of acute upper gastrointestinal bleeding (UGIB) is challenging in patients with cirrhosis, as it is responsible for severe complications and high mortality rates. Tranexamic acid (TXA) may help control the bleeding by counterbalancing cirrhosis-related hyperfibrinolysis. Still, there is a lack of unbiased data to conclude on its efficacy. The aim of this study is to evaluate the efficacy of TXA in the early treatment of acute UGIB in patients with cirrhosis.

METHODS AND ANALYSIS

This study is a multicentre, randomised, double-blind, placebo-controlled trial, for adult patients with cirrhosis presenting with an acute UGIB and allocated to one of two arms: TXA or placebo (saline). Physicians from emergency mobile services, emergency departments (EDs) or intensive care units (ICUs) can include patients. Besides study intervention, standard care for UGIB will be performed as recommended. Intervention will consist an intravenous infusion of 10 mL of TXA (1 g) or saline, immediately followed by three identical intravenous infusions over 8 hours each (total dose of 4 g of TXA or 40 mL of placebo over 24 hours). Main analyses will be conducted in intention to treat on every patient included, then in modified intention to treat on patients with underlying lesion of portal hypertension visualised by endoscopy. The main objective is to show efficacy of TXA until day 5 on a composite criterion (bleeding control, rebleeding episodes and mortality). Secondary objectives aim at showing the efficacy of TXA on each individual component of the main outcome measure and others at 6 weeks and later (transjugular intrahepatic portosystemic shunt procedure, cirrhosis-specific complications, length of stay in ICU and in hospital, safety and tolerance of TXA, liver transplantation). Included patients will be followed up to 1 year after inclusion.500 patients will be necessary to show a reduction in the prevalence of the primary outcome from 30% to 18% with a bilateral alpha risk of 5% and a power of 80%.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Comité de Protection des Personnes Ile-de-France 1 (CPP-IDF1). Results will be disseminated via publications in peer-review medical journals and scientific forums.

PROTOCOL VERSION

This protocol is based on the latest version, as established on 11 October 2017 and validated by the IRB CPP Ile-de-France 1.

TRIAL REGISTRATION NUMBER

NCT03023189.

The use of tranexamic acid in microsurgery-is it safe?

Background

An appropriate and adequate blood flow and oxygen delivery is paramount to free flap viability and success. The perioperative use of tranexamic acid (TXA) is associated with less risk for blood loss and blood transfusion in trauma, gynaecology, ear nose and throat (ENT) and orthopaedic surgery. As an antifibrinolytic drug, TXA has generally been avoided in microsurgery. The aim of this study is to evaluate the safety and benefit of using TXA in microsurgery.

Methods

We performed a retrospective single centre cohort study at the Pyramid Clinic, Zurich, Switzerland, including 98 free tissue transfers for breast reconstruction from 2011 to 2013. According to the estimated blood loss, up to 3 g TXA were administered intravenously in 63 free flaps perioperatively.

Results

No thrombosis (0%) of micro-anastomosis and 5 haematomas (10.0%) occurred after administration of TXA. In the control group, 1 thrombosis (3.0%) of a flap-vein and 6 haematomas (18.2%) occurred. Blood loss was significant lower (P<0.001) after administration of TXA.

Conclusions

In this study, administration of TXA did not increase thrombosis in free tissue transfer and showed a reduced haematoma rate and significant reduction of blood loss. TXA is supposed to be safe and a reasonable adjunct for patients with anaemia and a higher intraoperative or postoperative blood loss.

The currency, completeness and quality of systematic reviews of acute management of moderate to severe traumatic brain injury: A comprehensive evidence map

OBJECTIVE

To appraise the currency, completeness and quality of evidence from systematic reviews (SRs) of acute management of moderate to severe traumatic brain injury (TBI).

METHODS

We conducted comprehensive searches to March 2016 for published, English-language SRs and RCTs of acute management of moderate to severe TBI. Systematic reviews and RCTs were grouped under 12 broad intervention categories. For each review, we mapped the included and non-included RCTs, noting the reasons why RCTs were omitted. An SR was judged as 'current' when it included the most recently published RCT we found on their topic, and 'complete' when it included every RCT we found that met its inclusion criteria, taking account of when the review was conducted. Quality was assessed using the AMSTAR checklist (trichotomised into low, moderate and high quality).

FINDINGS

We included 85 SRs and 213 RCTs examining the effectiveness of treatments for acute management of moderate to severe TBI. The most frequently reviewed interventions were hypothermia (n = 17, 14.2%), hypertonic saline and/or mannitol (n = 9, 7.5%) and surgery (n = 8, 6.7%). Of the 80 single-intervention SRs, approximately half (n = 44, 55%) were judged as current and two-thirds (n = 52, 65.0%) as complete. When considering only the most recently published review on each intervention (n = 25), currency increased to 72.0% (n = 18). Less than half of the 85 SRs were judged as high quality (n = 38, 44.7%), and nearly 20% were low quality (n = 16, 18.8%). Only 16 (20.0%) of the single-intervention reviews (and none of the five multi-intervention reviews) were judged as current, complete and high-quality. These included reviews of red blood cell transfusion, hypothermia, management guided by intracranial pressure, pharmacological agents (various) and prehospital intubation. Over three-quarters (n = 167, 78.4%) of the 213 RCTs were included in one or more SR. Of the remainder, 17 (8.0%) RCTs post-dated or were out of scope of existing SRs, and 29 (13.6%) were on interventions that have not been assessed in SRs.

CONCLUSION

A substantial number of SRs in acute management of moderate to severe TBI lack currency, completeness and quality. We have identified both potential evidence gaps and also substantial research waste. Novel review methods, such as Living Systematic Reviews, may ameliorate these shortcomings and enhance utility and reliability of the evidence underpinning clinical care.

Benefits of the tranexamic acid in head trauma with no extracranial bleeding: a prospective follow-up of 180 patients

INTRODUCTION

Tranexamic acid (TXA) is one of the debated therapies in the management of traumatic brain injury (TBI). We conducted this study to evaluate the benefits of TXA in TBI on the mortality and its safety in these patients.

METHODS

This was a prospective randomized open-label trial including all patients, aged at 18 years or older, hospitalized in the emergency room during a 13-month period, for TBI. After the realization of the body CT scan, the patients were included if they had intracranial bleeding, and were then randomized according to their medical file number to receive or not the TXA. The eligibility criteria were based on the uncertainty principle, patients with significant extracranial bleeding were excluded since there was evidence that TXA improve their outcome.

RESULTS

We enrolled 180 patients aged at 42 ± 20 years, with an 88% men-proportion. Subarachnoid haemorrhage was the most frequent lesion in the brain CT-scan (67.5%). After randomization, 96 patients were in the TXA group (53%). Demographic data, clinical, biological and radiological features were statistically comparable in the two groups of patients ('TXA' and 'noTXA'). The needs of transfusion or neurosurgery, the mortality rate, the in-hospital length of stay and the dependency at 28-post-traumatic day were similar in the two groups of patients. However, pulmonary embolism was statistically more frequent in 'TXA' group (11.5 versus 2.4%, p = 0.02).

CONCLUSION

TXA is an interesting treatment in haemorrhagic shock. Its efficiency in head trauma is still debated and controversial. Its impact on the mortality and the needs of transfusion or surgery were not demonstrated in this study. Nevertheless, its safety worth to be studied in larger samples as we found a higher rate of pulmonary embolism in the treated group.

Visual estimation of blood loss by UK pre-hospital clinicians: an observational study

AIM

To assess the accuracy of visual estimation of external blood loss by UK pre-hospital clinicians and to comment on its value during handover.

METHODS

A sample of 104 pre-hospital clinicians were shown eight staged scenarios showing varying amounts of blood loss and asked to estimate the amount of blood loss depicted. Participants included a range of pre-hospital clinicians from both NHS ambulance trusts and Helicopter Emergency Medical Services.

RESULTS

A wide distribution of estimates and therefore percentage error was observed in our study. Pre-hospital clinicians are inaccurate when estimating external blood loss at scene, regardless of training and skill level.

CONCLUSION

Visual estimation of blood loss is too inaccurate to be considered clinically worthwhile. Greater research focus is needed to investigate and validate better measures of blood loss that can be utilised in the pre-hospital and emergency medicine environment. Until evidence-based methods of estimation can be implemented, this information should not be included in hospital handovers.

Haemostatic therapies for acute spontaneous intracerebral haemorrhage

BACKGROUND

Outcome after spontaneous (non-traumatic) intracerebral haemorrhage (ICH) is influenced by haematoma volume; up to one-third of ICHs enlarge within 24 hours of onset. Early haemostatic therapy might improve outcome by limiting haematoma growth. This is an update of a Cochrane Review first published in 2006, and last updated in 2009.

OBJECTIVES

To examine 1) the effectiveness and safety of individual classes of haemostatic therapies, compared against placebo or open control, in adults with acute spontaneous intracerebral haemorrhage, and 2) the effects of each class of haemostatic therapy according to the type of antithrombotic drug taken immediately before ICH onset (i.e. anticoagulant, antiplatelet, or none).

SEARCH METHODS

We searched the Cochrane Stroke Trials Register, CENTRAL; 2017, Issue 11, MEDLINE Ovid, and Embase Ovid on 27 November 2017. In an effort to identify further published, ongoing, and unpublished randomised controlled trials (RCT), we scanned bibliographies of relevant articles and searched international registers of RCTs in November 2017.

SELECTION CRITERIA

We sought randomised controlled trials (RCTs) of any haemostatic intervention (i.e. pro-coagulant treatments such as coagulation factors, antifibrinolytic drugs, or platelet transfusion) for acute spontaneous ICH, compared with placebo, open control, or an active comparator, reporting relevant clinical outcome measures.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data, assessed risk of bias, and contacted corresponding authors of eligible RCTs for specific data if they were not provided in the published report of an RCT.

MAIN RESULTS

We included 12 RCTs involving 1732 participants. There were seven RCTs of blood clotting factors versus placebo or open control involving 1480 participants, three RCTs of antifibrinolytic drugs versus placebo or open control involving 57 participants, one RCT of platelet transfusion versus open control involving 190 participants, and one RCT of blood clotting factors versus fresh frozen plasma involving five participants. We were unable to include two eligible RCTs because they presented aggregate data for adults with ICH and other types of intracranial haemorrhage. We identified 10 ongoing RCTs. Across all seven criteria in the 12 included RCTs, the risk of bias was unclear in 37 (44%), high in 16 (19%), and low in 31 (37%). Only one RCT was at low risk of bias in all criteria.In one RCT of platelet transfusion versus open control for acute spontaneous ICH associated with antiplatelet drug use, there was a significant increase in death or dependence (modified Rankin Scale score 4 to 6) at day 90 (70/97 versus 52/93; risk ratio (RR) 1.29, 95% confidence interval (CI) 1.04 to 1.61, one trial, 190 participants, moderate-quality evidence). All findings were non-significant for blood clotting factors versus placebo or open control for acute spontaneous ICH with or without surgery (moderate-quality evidence), for antifibrinolytic drugs versus placebo (moderate-quality evidence) or open control for acute spontaneous ICH (moderate-quality evidence), and for clotting factors versus fresh frozen plasma for acute spontaneous ICH associated with anticoagulant drug use (no evidence).

AUTHORS' CONCLUSIONS

Based on moderate-quality evidence from one trial, platelet transfusion seems hazardous in comparison to standard care for adults with antiplatelet-associated ICH.We were unable to draw firm conclusions about the efficacy and safety of blood clotting factors for acute spontaneous ICH with or without surgery, antifibrinolytic drugs for acute spontaneous ICH, and clotting factors versus fresh frozen plasma for acute spontaneous ICH associated with anticoagulant drug use.Further RCTs are warranted, and we await the results of the 10 ongoing RCTs with interest.

Safety and efficacy of tranexamic acid for prevention of obstetric haemorrhage: an updated systematic review and meta-analysis

BACKGROUND

A number of clinical systematic review and meta-analysis have been published on the use of tranexamic in the obstetric setting. The aim of this meta-analysis was to evaluate the safety and effectiveness of tranexamic acid in reducing blood loss when given prior to caesarean delivery.

MATERIALS AND METHODS

We searched the Cochrane Wounds Specialized Register, Cochrane Central, MEDLINE (through PUBMED), Embase, and SCOPUS electronic databases. We also searched clinical trials registries for ongoing and unpublished studies, and checked reference lists to identify additional studies. We used no restrictions with respect to language and date of publication. Two review authors independently performed study selection, "Risk of bias" assessment, and data extraction. Initial disagreements were resolved by discussion, or by including a third review author when necessary.

RESULTS

We found 18 randomised controlled trials (RCTs) that met our inclusion criteria. Overall, 1,764 women receiving intravenous tranexamic acid for prevention of bleeding following caesarean sections and 1,793 controls receiving placebo were enrolled in the 18 RCTs evaluated. The use of tranexamic acid compared to controls (placebo or no intervention) reduces post-partum haemorrhage >400 mL (risk ratio [RR] 0.40, 95% confidence interval [CI] 0.24-0.65; 5 trials with a total of 786 participants), severe post-partum haemorrhage >1,000 mL (RR 0.32, 95% CI: 0.12-0.84; 5 trials with a total of 1,850 participants), and need for red blood cell transfusion (RR 0.30, 95% CI: 0.18-0.49; 10 trials with a total of 1,873 participants). No particular safety concerns on the use of this antifibrinolytic agent emerged from the analysis of the 18 RCTs included.

DISCUSSION

Overall, the results of this meta-analysis support the evidence of a beneficial effect of tranexamic acid in reducing blood loss and need for blood transfusion in pregnant women undergoing caesarean section.

Different resuscitation strategies and novel pharmacologic treatment with valproic acid in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death in young adults, and effective treatment strategies have the potential to save many lives. TBI results in coagulopathy, endothelial dysfunction, inflammation, cell death, and impaired epigenetic homeostasis, ultimately leading to morbidity and/or mortality. Commonly used resuscitation fluids such as crystalloids or colloids have several disadvantages and might even be harmful when administered in large quantities. There is a need for next-generation treatment strategies (especially in the prehospital setting) that minimize cellular damage, improve survival, and enhance neurological recovery. Pharmacologic treatment with histone deacetylase inhibitors, such as valproic acid, has shown promising results in animal studies of TBI and may therefore be an excellent example of next-generation therapy. This review briefly describes traditional resuscitation strategies for TBI combined with hemorrhagic shock and describes preclinical studies on valproic acid as a new pharmacologic agent in the treatment of TBI. It finally discusses limitations and future directions on the use of histone deacetylase inhibitors for the treatment of TBI.

Antifibrinolytic drugs for treating primary postpartum haemorrhage

BACKGROUND

Postpartum haemorrhage (PPH) - heaving bleeding within the first 24 hours after giving birth - is one of the main causes of death of women after childbirth. Antifibrinolytics, primarily tranexamic acid (TXA), have been shown to reduce bleeding in surgery and safely reduces mortality in trauma patients with bleeding without increasing the risk of adverse events.An earlier Cochrane review on treatments for primary PPH covered all the various available treatments - that review has now been split by types of treatment. This new review concentrates only on the use of antifibrinolytic drugs for treating primary PPH.

OBJECTIVES

To determine the effectiveness and safety of antifibrinolytic drugs for treating primary PPH.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (28 May 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), including cluster-randomised trials of antifibrinolytic drugs (aprotinin, TXA, epsilon-aminocaproic acid (EACA) and aminomethylbenzoic acid, administered by whatever route) for primary PPH in women.Participants in the trials were women after birth following a pregnancy of at least 24 weeks' gestation with a diagnosis of PPH, regardless of mode of birth (vaginal or caesarean section) or other aspects of third stage management.We have not included quasi-randomised trials, or cross-over studies. Studies reported as abstracts have not been included if there was insufficient information to allow assessment of risk of bias.In this review we only identified studies looking at TXA.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from each study using an agreed form. We entered data into Review Manager software and checked for accuracy.For key review outcomes, we rated the quality of the evidence as 'high', 'moderate', 'low' or 'very low' according to the GRADE approach.

MAIN RESULTS

Three trials (20,412 women) met our inclusion criteria. Two trials (20,212 women) compared intravenous (IV) TXA with placebo or standard care and were conducted in acute hospital settings (labour ward, emergency department) (in high-, middle- and low-income countries).One other trial (involving 200 women) was conducted in Iran and compared IV TXA with rectal misoprostol, but did not report on any of this review's primary or GRADE outcomes. There were no trials that assessed EACA, aprotinin or aminomethylbenzoic acid.Standard care plus IV TXA for the treatment of primary PPH compared with placebo or standard care aloneTwo trials (20,212 women) assessed the effect of TXA for the treatment of primary PPH compared with placebo or standard care alone. The larger of these (The WOMAN trial) contributed over 99% of the data and was assessed as being at low risk of bias. The quality of the evidence varied for different outcomes, Overall, evidence was mainly graded as moderate to high quality.The data show that IV TXA reduces the risk of maternal death due to bleeding (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.65 to 1.00; two trials, 20,172 women; quality of evidence: moderate). The quality of evidence was rated as moderate due to imprecision of effect estimate. The effect was more evident in women given treatment between one and three hours after giving birth with no apparent reduction when given after three hours (< one hour = RR 0.80, 95% CI 0.55 to 1.16; one to three hours = RR 0.60, 95% CI 0.41 to 0.88; > three hours = RR 1.07, 95% 0.76 to 1.51; test for subgroup differences: Chi² = 4.90, df = 2 (P = 0.09), I² = 59.2%). There was no heterogeneity in the effect by mode of birth (test for subgroup differences: Chi² = 0.01, df = 1 (P = 0.91), I² = 0%). There were fewer deaths from all causes in women receiving TXA, although the 95% CI for the effect estimate crosses the line of no effect (RR 0.88, 95% CI 0.74 to 1.05; two trials, 20,172 women, quality of evidence: moderate). Results from one trial with 151 women suggest that blood loss of ≥ 500 mL after randomisation may be reduced (RR 0.50, 95% CI 0.27 to 0.93; one trial, 151 women; quality of evidence: low). TXA did not reduce the risk of serious maternal morbidity (RR 0.99, 95% CI 0.83 to 1.19; one trial, 20,015 women; quality of evidence: high), hysterectomy to control bleeding (RR 0.95, 95% CI 0.81 to 1.12; one trial, 20,017 women; quality of evidence: high) receipt of blood transfusion (any) (RR 1.00, 95% CI 0.97 to 1.03; two trials, 20,167 women; quality of evidence: moderate) or maternal vascular occlusive events (any), although results were imprecise for this latter outcome (RR 0.88, 95% CI 0.54 to 1.43; one trial, 20,018 women; quality of evidence: moderate). There was an increase in the use of brace sutures in the TXA group (RR 1.19, 95% CI 1.01, 1.41) and a reduction in the need for laparotomy for bleeding (RR 0.64, 95% CI 0.49, 0.85).

AUTHORS' CONCLUSIONS

TXA when administered intravenously reduces mortality due to bleeding in women with primary PPH, irrespective of mode of birth, and without increasing the risk of thromboembolic events. Taken together with the reliable evidence of the effect of TXA in trauma patients, the evidence suggests that TXA is effective if given as early as possible.Facilities for IV administration may not be available in non-hospital settings therefore, alternative routes to IV administration need to be investigated.

The effectiveness and safety of antifibrinolytics in patients with acute intracranial haemorrhage: statistical analysis plan for an individual patient data meta-analysis

Introduction: The Antifibrinolytic Trialists Collaboration aims to increase knowledge about the effectiveness and safety of antifibrinolytic treatment by conducting individual patient data (IPD) meta-analyses of randomised trials. This article presents the statistical analysis plan for an IPD meta-analysis of the effects of antifibrinolytics for acute intracranial haemorrhage. Methods: The protocol for the IPD meta-analysis has been registered with PROSPERO (CRD42016052155). We will conduct an individual patient data meta-analysis of randomised controlled trials with 1000 patients or more assessing the effects of antifibrinolytics in acute intracranial haemorrhage. We will assess the effect on two co-primary outcomes: 1) Death in hospital within 30 days of randomisation, and 2) Death  or dependency at final follow-up within 90 days of randomisation. The co-primary outcomes will be limited to patients treated within three hours of injury or stroke onset. We will report treatment effects using odds ratios and 95% confidence intervals. We use logistic regression models to examine how the effect of antifibrinolytics vary by time to treatment, severity of intracranial bleeding, and age. We will also examine the effect of antifibrinolytics on secondary outcomes including death, dependency, vascular occlusive events, seizures, and neurological outcomes. Secondary outcomes will be assessed in all patients irrespective of time of treatment. All analyses will be conducted on an intention-to-treat basis. Conclusions: This IPD meta-analysis will examine important clinical questions about the effects of antifibrinolytic treatment in patients with intracranial haemorrhage that cannot be answered using aggregate data. With IPD we can examine how effects vary by time to treatment, bleeding severity, and age, to gain better understanding of the balance of benefit and harms on which to base recommendations for practice.

The effect of tranexamic acid on blood loss and maternal outcome in the treatment of persistent postpartum hemorrhage: A nationwide retrospective cohort study

Background

Recent results show a protective effect of tranexamic acid on death due to bleeding in patients with postpartum hemorrhage in low- and middle-resource countries. We quantify the association between early administration of tranexamic acid compared to late or no administration and severe acute maternal morbidity and blood loss among women suffering from persistent severe postpartum hemorrhage in a high-income country.

Methods and findings

We performed a nationwide retrospective cohort study in 61 hospitals in the Netherlands. The study population consisted of 1260 women with persistent postpartum hemorrhage who had received at least four units of red cells, or fresh frozen plasma or platelets in addition to red cells. A review of medical records was performed and cross-referenced with blood bank data. The composite endpoint comprised maternal morbidity (hysterectomy, ligation of the uterine arteries, emergency B-Lynch suture, arterial embolization or admission into an intensive care unit) and mortality.

Results

247 women received early tranexamic acid treatment. After adjustment for confounding, odds ratio for the composite endpoint for early tranexamic acid (n = 247) versus no/late tranexamic acid (n = 984) was 0.92 (95% confidence interval (CI) 0.66 to 1.27). Propensity matched analysis confirmed the absence of a difference between women with and without tranexamic acid. Blood loss after administration of first line therapy did not differ significantly between the two groups (adjusted difference -177 mL, CI -509.4 to +155.0).

Conclusions

Our findings suggest that in a high-resource country the effect of tranexamic acid on both blood loss and the combined endpoint of maternal mortality and morbidity may be disappointing.

Assessment of Haemostasis in patients undergoing emergent neurosurgery by rotational Elastometry and standard coagulation tests: a prospective observational study

BACKGROUND

Rotational elastometry (ROTEM) has been shown useful to monitor coagulation in trauma patients and in major elective surgery. In this study, we aimed to evaluate the utility of ROTEM to identify hemostatic disturbances and to predict the need for transfusion, compared with standard coagulation tests (SCTs) in patients undergoing emergent neurosurgery.

METHODS

Over a four-year period, adult patients who met criteria for emergent neurosurgery lasting more than 90 min were included in the study. Blood was collected preoperatively and analyzed with SCTs (international normalized ratio [INR], fibrinogen concentration, prothrombin time [PT or Quick], partial thromboplastine time [PTT], fibrinogen concentration and platelet count), and ROTEM assays. Correlations between SCTs and ROTEM parameters as well as receiver operating characteristic curves were performed to detect a coagulopathic pattern based on standard criteria and the need for transfusing at least 3 units of packed red blood cells (PRBCs).

RESULTS

In a cohort of 92 patients, 39 (42%) required ≥3 PRBCs and a coagulopathic pattern was identified in 32 patients based on SCTs and in 19 based on ROTEM. There was a strong correlation between PTT and INTEM coagulation time (R = 0.76) as well as between fibrinogen concentrations and FIBTEM maximal clot firmess (R = 0.70). The need for transfusion (≥ 3 PRBCs) was best predicted by the maximal clot firmess of EXTEM and FIBTEM (AUC of 0.72 and 0.71, respectively) and by fibrinogen concentration (AUC of 0.70).

CONCLUSIONS

In patients undergoing emergent neurosurgery, ROTEM analysis provides valid markers of early coagulopathy and predictors of blood transfusion requirements.

Fibrinolysis in trauma: a review

Fibrinolytic dysregulation is an important mechanism in traumatic coagulopathy. It is an incompletely understood process that consists of a spectrum ranging from excessive breakdown (hyperfibrinolysis) and the shutdown of fibrinolysis. Both hyperfibrinolysis and shutdown are associated with excess mortality and post-traumatic organ failure. The pathophysiology appears to relate to endothelial injury and hypoperfusion, with several molecular markers identified in playing a role. Although there are no universally accepted diagnostic tests, viscoelastic studies appear to offer the greatest potential for timely identification of patients presenting with fibrinolytic dysregulation. Treatment is multimodal, involving prompt hemorrhage control and resuscitation, with controversy surrounding the use of antifibrinolytic drug therapy. This review presents the current evidence on the pathophysiology, diagnostic challenges, as well as the management of this hemostatic dysfunction.

LEVEL OF EVIDENCE

Level III.

A nested mechanistic sub-study into the effect of tranexamic acid versus placebo on intracranial haemorrhage and cerebral ischaemia in isolated traumatic brain injury: study protocol for a randomised controlled trial (CRASH-3 Trial Intracranial Bleeding Mechanistic Sub-Study [CRASH-3 IBMS])

Background

Tranexamic acid prevents blood clots from breaking down and reduces bleeding. However, it is uncertain whether tranexamic acid is effective in traumatic brain injury. The CRASH-3 trial is a randomised controlled trial that will examine the effect of tranexamic acid (versus placebo) on death and disability in 13,000 patients with traumatic brain injury. The CRASH-3 trial hypothesizes that tranexamic acid will reduce intracranial haemorrhage, which will reduce the risk of death. Although it is possible that tranexamic acid will reduce intracranial bleeding, there is also a potential for harm. In particular, tranexamic acid may increase the risk of cerebral thrombosis and ischaemia. The protocol detailed here is for a mechanistic sub-study nested within the CRASH-3 trial. This mechanistic sub-study aims to examine the effect of tranexamic acid (versus placebo) on intracranial bleeding and cerebral ischaemia.

Methods

The CRASH-3 Intracranial Bleeding Mechanistic Sub-Study (CRASH-3 IBMS) is nested within a prospective, double-blind, multi-centre, parallel-arm randomised trial called the CRASH-3 trial. The CRASH-3 IBMS will be conducted in a cohort of approximately 1000 isolated traumatic brain injury patients enrolled in the CRASH-3 trial. In the CRASH-3 IBMS, brain scans acquired before and after randomisation are examined, using validated methods, for evidence of intracranial bleeding and cerebral ischaemia. The primary outcome is the total volume of intracranial bleeding measured on computed tomography after randomisation, adjusting for baseline bleeding volume. Secondary outcomes include progression of intracranial haemorrhage (from pre- to post-randomisation scans), new intracranial haemorrhage (seen on post- but not pre-randomisation scans), intracranial haemorrhage following neurosurgery, and new focal ischaemic lesions (seen on post-but not pre-randomisation scans). A linear regression model will examine whether receipt of the trial treatment can predict haemorrhage volume. Bleeding volumes and new ischaemic lesions will be compared across treatment groups using relative risks and 95% confidence intervals.

Discussion

The CRASH-3 IBMS will provide an insight into the mechanism of action of tranexamic acid in traumatic brain injury, as well as information about the risks and benefits. Evidence from this trial could inform the management of patients with traumatic brain injury.

Trial registration

The CRASH-3 trial was prospectively registered and the CRASH-3 IBMS is an addition to the original protocol registered at the International Standard Randomised Controlled Trials registry (ISRCTN15088122) 19 July 2011, and ClinicalTrials.gov on 25 July 2011 (NCT01402882).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2073-6) contains supplementary material, which is available to authorized users.

Tranexamic acid and trauma-induced coagulopathy

Tranexamic acid (TXA) is a synthetic derivative of the amino acid lysine that inhibits fibrinolysis by blocking the interaction of plasminogen with the lysine residues of fibrin. Historically, TXA is commonly used for reduction of blood loss in perioperative situations, while recently it has attracted attention for clinical use in the trauma field. In 2010, the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage 2 (CRASH-2) trial demonstrated that intravenous administration of TXA improved mortality significantly in trauma patients with significant bleeding. After the launch of its sensational results, the main stream treatment protocol in trauma changed worldwide to include TXA administration.

In this review, first we summarize the recent evidence or recommendations in the related guidelines concerning TXA. Also, we next tried to explore in detail not only the benefits but also the harm introduced by TXA in trauma patients, because the main adverse event results for TXA, such as vascular occlusive events in the CRASH-2 trial, are still being discussed in several papers. Thus, we briefly summarized the evidence for the safety of TXA administration by a systematic review method using observational studies. Consequently, the pooled relative risk for venous thromboembolisms was 1.61 (95% CI, 0.86–3.01), indicating a non-significant increase in the venous thromboembolism risk of TXA therapy.

Regarding the basic mechanism, TXA potentially possesses the risk of venous thromboembolisms, so it should be used cautiously and selectively. Further investigation is needed to delineate the optimal targeted trauma patients to earn the maximum survival benefits with minimized risk of thrombotic complications.