Impact of Preemptive Fibrinogen Concentrate on Transfusion Requirements in Liver Transplantation: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial

Practical Coagulation Management in Liver Transplantation Through Point-of-Care Analysis Using the TEG 6s Global Hemostasis System in Japan

Liver transplantation (LT) is the standard treatment for end-stage liver disease. However, owing to a precarious balance between pro- and anticoagulation factors, patients undergoing LT are at high risk of massive bleeding and vascular thromboembolic complications. Thromboelastography (TEG) allows for the rapid, comprehensive, and accurate identification of coagulation monitoring undergoing LT. Newly released TEG 6s global hemostasis systems have been introduced, which we hypothesized could contribute to practical coagulation management in LT. TEG 6s was used for 15 patients undergoing LT at eight preset times during and after LT. Anesthesiologists and a surgical intensive care team managed coagulation during and after LT, based fully on TEG 6s findings. We focused on the citrated kaolin reaction time, citrated kaolin maximum amplitude, and functional fibrinogen maximum amplitude. TEG 6s was also used to determine transfusion principles with a focus on the details of cases with difficult to manage coagulation. Among 15 LT patients, six had massive bleeding-related complications and vascular thromboembolic complications. Case management and detailed TEG 6s results were reviewed. We recommend using the TEG 6s to obtain a comprehensive understanding of coagulation management as this global hemostasis system offers superior insights compared with standard laboratory tests.

Safety of Fibrinogen Concentrate for Correcting Perioperative Bleeding-Associated Hypofibrinogenemia in Adults: A Single-Center Experience

Background: Surgery often leads to bleeding associated with hypofibrinogenemia. Supplementation with fibrinogen concentrate appears to be effective and safe, although findings from studies are inconsistent. The primary aim of this study was to assess the safety of fibrinogen concentrate during the perioperative period. Methods: This single-centre, prospective, observational study included adult patients undergoing scheduled or emergency surgery related to bleeding coagulopathy and the administration of fibrinogen concentrate. Patients were followed until their discharge from the institution. Comprehensive data were collected, including age, sex, type of surgery, associated comorbidities, anticoagulant and/or anti-aggregating therapy, and the number of blood transfusions. Laboratory data on plasma fibrinogen concentration, haemoglobin, and platelet count before and after surgery were also collected. The primary outcomes were the mortality rate at discharge and any reported thrombotic or thromboembolic events, including deep vein thrombosis, pulmonary embolism, and myocardial infarction. Results: The study included 91 adult patients who had undergone surgery, with 29 surgeries (32%) conducted in an emergency setting. The mean age was 59.2 years, and 53.8% were male. Major bleeding occurred in 29 cases, mainly in older males and those on anticoagulant therapy. The pre-operative fibrinogen level averaged 161 mg/dL, and the average dosage of fibrinogen concentrate administered was 2.7 g. Eight patients died (8.8%), mostly due to septic or cardiogenic shock, with deaths being more frequent in emergency settings. Thromboembolic events occurred in eight patients, none of whom died. No additional adverse events directly related to the administration of fibrinogen concentrate were reported. Conclusions: Our findings suggest a favourable safety profile for fibrinogen concentrate in surgical patients, as evidenced by a low incidence of deaths and thromboembolic events, which were primarily attributed to other factors. Future research should strive to increase statistical robustness to further illuminate clinically significant patient safety measures.

Safety of Fibrinogen Concentrate in Non-Trauma and Non-Obstetric Adult Patients during Perioperative Care: Systematic Review and Meta-Analysis

Background: Low fibrinogen levels are associated with an increased risk of perioperative bleeding. However, there is an ongoing debate over the ideal treatment threshold, the benefits of prophylactic supplementation with fibrinogen concentrate, and the best source of fibrinogen. While fibrinogen concentrate supplementation is being widely used to treat bleeding related to acquired haemostatic deficiencies, there is a lack of evidence regarding its dosage, effectiveness, and safety. This systematic review provides an up-to-date summary of the relationship between fibrinogen concentrate supplementation and safety measures in the perioperative care of non-trauma, non-obstetric adult patients. Methods: A comprehensive online search was conducted on PubMed/Medline, EMBASE, Scopus, Web of Science, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials. Results: This systematic review and meta-analysis encompasses ten studies involving 1391 patients. There was a decreased risk of total thromboembolic events in patients treated with fibrinogen compared to the control (OR 0.65, 95% CI 0.43 to 0.98, I2 = 0%). In addition, when fibrinogen was used prophylactically, it resulted in shorter ICU stays (MD -1.50, 95% CI -2.64 to -0.36), when set against its therapeutic use. A sensitivity analysis on cardiovascular surgery studies did not reveal any statistically significant difference. Conclusions: The use of fibrinogen concentrate in the perioperative care of non-trauma and non-obstetric adult patients may lead to potential benefits.

Long-Term Safety Analysis of a Fibrinogen Concentrate (RiaSTAP®/Haemocomplettan® P)

Fibrinogen concentrate treatment is recommended for acute bleeding episodes in adult and pediatric patients with congenital and acquired fibrinogen deficiency. Previous studies have reported a low risk of thromboembolic events (TEEs) with fibrinogen concentrate use; however, the post-treatment TEE risk remains a concern. A retrospective evaluation of RiaSTAP®/Haemocomplettan® P (CSL Behring, Marburg, Germany) post-marketing data was performed (January 1986-June 2022), complemented by a literature review of published studies. Approximately 7.45 million grams of fibrinogen concentrate was administered during the review period. Adverse drug reactions (ADRs) were reported in 337 patients, and 81 (24.0%) of these patients experienced possible TEEs, including 14/81 (17.3%) who experienced fatal outcomes. Risk factors and the administration of other coagulation products existed in most cases, providing alternative explanations. The literature review identified 52 high-ranking studies with fibrinogen concentrate across various clinical areas, including 26 randomized controlled trials. Overall, a higher number of comparative studies showed lower rates of ADRs and/or TEEs in the fibrinogen group versus the comparison group(s) compared with those that reported higher rates or no differences between groups. Post-marketing data and clinical studies demonstrate a low rate of ADRs, including TEEs, with fibrinogen concentrate treatment. These findings suggest a favorable safety profile of fibrinogen concentrate, placing it among the first-line treatments effective for managing intraoperative hemostatic bleeding.

Guidelines for the management of coagulation disorders in patients with cirrhosis

Coagulation management in the patient with cirrhosis has undergone a significant transformation since the beginning of this century, with the concept of a rebalancing between procoagulant and anticoagulant factors. The paradigm that patients with cirrhosis have a greater bleeding tendency has changed, as a result of this rebalancing. In addition, it has brought to light the presence of complications related to thrombotic events in this group of patients. These guidelines detail aspects related to pathophysiologic mechanisms that intervene in the maintenance of hemostasis in the patient with cirrhosis, the relevance of portal hypertension, mechanical factors for the development of bleeding, modifications in the hepatic synthesis of coagulation factors, and the changes in the reticuloendothelial system in acute hepatic decompensation and acute-on-chronic liver failure. They address new aspects related to the hemorrhagic complications in patients with cirrhosis, considering the risk for bleeding during diagnostic or therapeutic procedures, as well as the usefulness of different tools for diagnosing coagulation and recommendations on the pharmacologic treatment and blood-product transfusion in the context of hemorrhage. These guidelines also update the knowledge regarding hypercoagulability in the patient with cirrhosis, as well as the efficacy and safety of treatment with the different anticoagulation regimens. Lastly, they provide recommendations on coagulation management in the context of acute-on-chronic liver failure, acute liver decompensation, and specific aspects related to the patient undergoing liver transplantation.

Population pharmacokinetic modelling of fibrinogen in patients with congenital or acquired-chronic or acute-hypofibrinogenaemia

AIMS

Fibrinogen is the key substrate for coagulation. Fibrinogen pharmacokinetics (PK) after single doses of fibrinogen concentrate (FC), using modelling approaches, has only been evaluated in congenital afibrinogenaemic patients. The aims of this study are to characterize the fibrinogen PK in patients with acquired-chronic (cirrhosis) or acute-hypofibrinogenaemia (critical haemorrhage), showing endogenous production. Influencing factors of differences on the fibrinogen PK between subpopulations will be identified.

METHODS

A total of 428 time-concentration values from 132 patients were recorded. Eighty-two out of 428 values were from 41 cirrhotic patients administered with placebo and 90 out of 428 were from 45 cirrhotic patients that were given FC, 161 out of 428 values were from 14 afibrinogenaemic patients and 95 out of 428 values were from 32 severe acute trauma haemorrhagic patients. A turnover model that accounted for endogenous production and exogenous dose was fitted using NONMEM74. The production rate (Ksyn), distribution volume (V), plasma clearance (CL) and concentration yielding to 50% of maximal fibrinogen production (EC50) were estimated.

RESULTS

Fibrinogen disposition was described by a one-compartment model with CL and V values of 0.0456 L·h-1 and 4.34 L·70 kg-1 , respectively. Body weight was statistically significant in V. Three different Ksyn values were identified that increased from 0.00439 g·h-1 (afibrinogenaemia), to 0.0768 g·h-1 (cirrhotics) and 0.1160 g·h-1 (acute severe trauma). EC50 was of 0.460 g·L-1 .

CONCLUSIONS

This model will be key as a support tool for dose calculation to achieve specified target fibrinogen concentrations, in each of the studied populations.

Patient Blood Management in Liver Transplant—A Concise Review

Transfusion of blood products in orthotopic liver transplantation (OLT) significantly increases post-transplant morbidity and mortality and is associated with reduced graft survival. Based on these results, an active effort to prevent and minimize blood transfusion is required. Patient blood management is a revolutionary approach defined as a patient-centered, systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient’s own blood while promoting patient safety and empowerment. This approach is based on three pillars of treatment: (1) detecting and correcting anemia and thrombocytopenia, (2) minimizing iatrogenic blood loss, detecting, and correcting coagulopathy, and (3) harnessing and increasing anemia tolerance. This review emphasizes the importance of the three-pillar nine-field matrix of patient blood management to improve patient outcomes in liver transplant recipients.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Preoperative Fibrinogen Level and Bleeding in Liver Transplantation for End-stage Liver Disease: A Cohort Study

BACKGROUND

Liver transplantation is a high-risk surgery associated with important perioperative bleeding and transfusion needs. Uncertainties remain on the association between preoperative fibrinogen level and bleeding in this population.

METHODS

We conducted a cohort study that included all consecutive adult patients undergoing a liver transplantation for end-stage liver disease in 1 center. We analyzed the association between the preoperative fibrinogen level and bleeding-related outcomes. Our primary outcome was intraoperative blood loss, and our secondary outcomes were estimated perioperative blood loss, intraoperative and perioperative red blood cell transfusions, reinterventions for bleeding and 1-y graft and patient survival. We estimated linear regression models and marginal risk models adjusted for all important potential confounders. We used restricted cubic splines to explore potential nonlinear associations and reported dose-response curves.

RESULTS

We included 613 patients. We observed that a lower fibrinogen level was associated with a higher intraoperative blood loss, a higher estimated perioperative blood loss and a higher risk of intraoperative and perioperative red blood cell transfusions (nonlinear effects). Based on an exploratory analysis of the dose-response curves, these effects were observed below a threshold value of 3 g/L for these outcomes. We did not observe any association between preoperative fibrinogen level and reinterventions, 1-y graft survival or 1-y patient survival.

CONCLUSIONS

This study suggests that a lower fibrinogen level is associated with bleeding in liver transplantation. The present results may help improving the selection of patients for further studies on preoperative fibrinogen administration in liver transplant recipients with end-stage liver disease.

Viscoelastic Management of Coagulopathy during the Perioperative Period of Liver Transplantation

Viscoelastic testing (VET) in liver transplantation (LT) has been used since its origin, in combination with standard laboratory testing (SLT). There are only a few, small, randomized controlled trials that demonstrated a reduction in transfusion rates using VET to guide coagulation management. Retrospective analyses contrasting VET to SLT have demonstrated mixed results, with a recent concern for overtreatment and the increase in postoperative thrombotic events. An oversight of many studies evaluating VET in LT is a single protocol that does not address the different phases of surgery, in addition to pre- and postoperative management. Furthermore, the coagulation spectrum of patients entering and exiting the operating room is diverse, as these patients can have varying anatomic and physiologic risk factors for thrombosis. A single transfusion strategy for all is short sighted. VET in combination with SLT creates the opportunity for personalized resuscitation in surgery which can address the many challenges in LT where patients are at a paradoxical risk for both life-threatening bleeding and clotting. With emerging data on the role of rebalanced coagulation in cirrhosis and hypercoagulability following LT, there are numerous potential roles in VET management of LT that have been unaddressed.

Blood component requirements in liver transplantation: effect of 2 thromboelastometry-guided strategies for bolus fibrinogen infusion-the TROMBOFIB randomized trial

BACKGROUND

A low plasma fibrinogen level influences blood component transfusion. Thromboelastometry provides clinical guidance for fibrinogen replacement in liver transplantation (LT).

OBJECTIVES

We hypothesized that infusions of fibrinogen concentrate to reach an A10_FibTem value of 11 mm during LT could reduce red blood cell (RBC) and other component and fluid requirements in comparison to standard care.

METHODS

This randomized, blinded, multicenter trial in 3 hospitals enrolled 189 LT-scheduled patients allocated to an intervention target (A10_FibTem, 11 mm) or a standard target (A10_FibTem, 8 mm); 176 patients underwent LT with fibrinogen replacement. Data were analyzed by intention-to-treat (intervention group, 91; control group, 85). Blood was extracted, and fibrinogen kits were prepared to bring each patient's fibrinogen level to the assigned target at the start of LT, after portal vein clamping, and after graft reperfusion. The main outcome was the proportion of patients requiring RBC transfusion during LT or within 24 hours.

RESULTS

The proportion of patients requiring RBCs did not differ between the groups: intervention, 74.7% (95% CI, 65.5%-83.3%); control, 72.9% (95% CI, 62.2%-82.0%); absolute difference, 1.8% (95% CI, -11.1% to 14.78%) (P = .922). Thrombotic events occurred in 4% of the patients in both groups; reoperation and retransplantation rates and mortality did not differ. Nearly 70% of the patients in both groups required fibrinogen concentrate to reach the target. Using an 11-mm A10_FibTem target increased the maximum clot firmness without affecting safety. However, this change provided no clinical benefits.

CONCLUSION

The similar low plasma fibrinogen concentrations could explain the lack of significant between-group outcomes.

Coagulopathy and hemostasis management in patients undergoing liver transplantation: Defining a dynamic spectrum across phases of care

Patients with acute and chronic liver disease present with a wide range of disease states and severity that may require liver transplantation (LT). Physiologic alterations occur that are dynamic throughout all phases of perioperative care, creating complex management scenarios that necessitate multidisciplinary clinical care. Specifically, alterations in hemostasis in liver disease can be pronounced and evolve with disease progression over time. Recent studies and society guidance address this emerging paradigm and offer recommendations to assist with hemostatic management in patients with liver disease. However, patients undergoing LT are unique and diverse, often with unstable disease that requires specialized approaches. Our aim is to provide a focused review of hemostatic management of the LT patient, distinguish unique aspects of the three main phases of care (before LT, perioperative, and after LT), and identify knowledge gaps and critical areas of future research.

The Edge of Unknown: Postoperative Critical Care in Liver Transplantation

Perioperative care of patients undergoing liver transplantation (LT) is very complex. Metabolic derangements, hypothermia, coagulopathy and thromboses, severe infections, and graft dysfunction can affect outcomes. In this manuscript, we discuss several perioperative problems that can be encountered in LT recipients. The authors present the most up-to-date information regarding predicting and treating hemodynamic instability, coagulation monitoring and management, postoperative ventilation strategies and early extubation, management of infections, and ESLD-related pulmonary complications. In addition, early post-transplant allograft dysfunction will be discussed.

EASL Clinical Practice Guidelines on prevention and management of bleeding and thrombosis in patients with cirrhosis

The prevention and management of bleeding and thrombosis in patients with cirrhosis poses several difficult clinical questions. These Clinical Practice Guidelines have been developed to provide practical guidance on debated topics, including current views on haemostasis in liver disease, controversy regarding the need to correct thrombocytopenia and abnormalities in the coagulation system in patients undergoing invasive procedures, and the need for thromboprophylaxis in hospitalised patients with haemostatic abnormalities. Multiple recommendations in this document are based on interventions that the panel feels are not useful, even though widely applied in clinical practice.

Liver transplant with controlled donors after circulatory death with normothermic regional perfusion and brain dead donors: A multicenter cohort study of transfusion, one-year graft survival and mortality

BACKGROUND

Controlled donation after circulatory death (cDCD) has expanded the donor pool for liver transplantation (LT). However, transfusion requirements and perioperative outcomes should be elucidated. The aim of this multicenter study was to assess red blood cell (RBC) transfusions, one-year graft and patient survival after LT after cDCD with normothermic regional perfusion (NRP) compared with donors after brain death (DBD).

METHODS

591 LT carried out in ten centers during 2019 were reviewed. Thromboelastometry was used to manage coagulation and blood product transfusion in all centers. Normothermic regional perfusion was the standard technique for organ recovery.

RESULTS

447 patients received DBD and 144 cDCD with NRP. Baseline MCF Extem was lower in the cDCD group There were no differences in the percentage of patients (63% vs. 61% p = 0.69), nor in the number of RBC units transfused (4.7 (0.2) vs 5.5 (0.4) in DBD vs cDCD, p = 0.11. Twenty-six patients (6%) died during admission for LT in the DBD group compared with 3 patients (2%) in the cDCD group (p = 0.15). To overcome the bias due to a worse coagulation profile in cDCD recipients, matched samples were compared. No differences in baseline laboratory data, or in intraoperative use of RBC or one-year outcome data were observed between DBD and cDCD recipients.

CONCLUSIONS

cDCD with NRP is not associated with increased RBC transfusion. No differences in graft and patient survival between cDCD and DBD were found. Donors after controlled circulatory death with NRP can increasingly be utilized with safety, improving the imbalance between organ donors and the ever-growing demand.

Hemostasis testing in patients with liver dysfunction: Advantages and caveats

Due to concomitant changes in pro- and anti-coagulant mechanisms, patients with liver dysfunction have a “rebalanced hemostasis”, which can easily be tipped toward either a hypo- or a hypercoagulable phenotype. Clinicians are often faced with the question whether patients with chronic liver disease undergoing invasive procedures or surgery and those having active bleeding require correction of the hemostasis abnormalities. Conventional coagulation screening tests, such as the prothrombin time/international normalized ratio and the activated partial thromboplastin time have been demonstrated to have numerous limitations in these patients and do not predict the risk of bleeding prior to high-risk procedures. The introduction of global coagulation assays, such as viscoelastic testing (VET), has been an important step forward in the assessment of the overall hemostasis profile. A growing body of evidence now suggests that the use of VET might be of significant clinical utility to prevent unnecessary infusion of blood products and to improve outcomes in numerous settings. The present review discusses the advantages and caveats of both conventional and global coagulation assays to assess the risk of bleeding in patients with chronic liver disease as well as the current role of transfusion and hemostatic agents to prevent or manage bleeding.

Clinical use of tranexamic acid: evidences and controversies

Tranexamic acid (TXA) significantly reduces blood loss in a wide range of surgical procedures and improves survival rates in obstetric and trauma patients with severe bleeding. Although it mainly acts as a fibrinolysis inhibitor, it also has an anti-inflammatory effect, and may help attenuate the systemic inflammatory response syndrome found in some cardiac surgery patients. However, the administration of high doses of TXA has been associated with seizures and other adverse effects that increase the cost of care, and the administration of TXA to reduce perioperative bleeding needs to be standardized. Tranexamic acid is generally well tolerated, and most adverse reactions are considered mild or moderate. Severe events are rare in clinical trials, and literature reviews have shown tranexamic acid to be safe in several different surgical procedures. However, after many years of experience with TXA in various fields, such as orthopedic surgery, clinicians are now querying whether the dosage, route and interval of administration currently used and the methods used to control and analyze the antifibrinolytic mechanism of TXA are really optimal. These issues need to be evaluated and reviewed using the latest evidence to improve the safety and effectiveness of TXA in treating intracranial hemorrhage and bleeding in procedures such as liver transplantation, and cardiac, trauma and obstetric surgery.

Baseline haemoglobin and thromboelastometry are predictive of red blood cell requirements and one-year mortality in liver transplantation

BACKGROUND

To determine the predictive capacity of baseline haemoglobin and maxim clot firmness (MCF) EXTEM thromboelastometry for intraoperative red blood cell (RBC) requirements and its influence on mortality.

METHODS

591 adult liver transplant (LT) recipients from ten Spanish centres were reviewed. The main outcomes were the percentage of patients who received RBC and massive transfusion (≥ 6 RBC units), RBC units transfused, and mortality.

RESULTS

76 % received a donor after brain death graft and 24 % a controlled donor after circulatory death graft. Median (interquartile ranges) RBC transfusion was 2 (0-4) units, and 63 % of patients were transfused. Comparing transfused and non-transfused patients, mean (standard deviation) for baseline haemoglobin was 10.4 (2.1) vs. 13.0 (1.9) g/dl (p = 0.001), EXTEM MCF was 51(11) vs. 55(9) mm (p = 0.001). Haemoglobin and EXTEM MCF were inversely associated with the need of transfusion odds ratio (OR) of 0.558 (95 % CI 0.497-0.627, p < 0.001) and OR 0.966 (95 % CI0.945-0.987, p = 0.002), respectively. Pre-operative baseline haemoglobin ≤ 10 g/dL predicted RBC transfusion, sensitivity of 93 % and specificity of 47 %. Massive transfusion (MT) was received by 19 % of patients. Haemoglobin ≤10 g/dL predicted MT with sensitivity 73 % and specificity of 52 %. One-year patient and graft survival were significantly lower in patients who required MT (78 % and 76 %, respectively) vs. those who did not (94 % and 93 %, respectively).

DISCUSSION

whereas EXTEM MCF is less dreterminant predicting RBC requirements, efforts are required to improve preoperative haemoglobin up to 10 g/dl in patients awaiting LT.

Prophylactic fibrinogen concentrate administration in surgical correction of paediatric craniosynostosis: A double-blind placebo-controlled trial

BACKGROUND

Surgical craniosynostosis repair in children is associated with massive blood loss and significant transfusion of blood products. Fibrinogen concentrate is claimed to be useful in reducing blood loss and transfusion requirements.

OBJECTIVE

We investigated whether prophylactic administration of fibrinogen concentrate will reduce blood loss and transfusion requirements during paediatric craniofacial surgery.

DESIGN

Randomised, placebo-controlled, double-blind clinical trial.

SETTING

University medical centre.

PATIENTS

A total of 114 infants and children up to 25 months of age (median age 10 months).

INTERVENTION

Surgical craniosynostosis repair by calvarial remodelling was performed in each patient. Patients were randomised to receive prophylactic fibrinogen concentrate (Haemocomplettan P) at a mean dose of 79 mg kg-1 body weight or placebo.

MAIN OUTCOME MEASURES

Primary outcome was the volume of transfused blood products. Secondary outcomes were peri-operative blood loss, duration of surgery, length of stay in the paediatric ICU, length of hospital stay, postoperative complications and adverse effects of fibrinogen concentrate infusion.

RESULTS

No significant differences (P < 0.05) were found in the volume of transfused blood products (median 29 ml kg-1 body weight vs. 29 ml kg-1 body weight), intra-operative estimated blood loss (45 vs. 46 ml kg-1), calculated blood loss (57 vs. 53 ml kg-1), or postoperative blood loss (24 vs. 24 ml kg-1) between the intervention and placebo groups. In addition, duration of surgery, length of stay in the paediatric ICU, hospital stay and complications were not significantly different between the two groups.

CONCLUSION

During surgical craniosynostosis repair in young children, prophylactic administration of high-dose fibrinogen concentrate did not reduce the amount of transfused blood products or decrease peri-operative blood loss.

TRIAL REGISTRATION

National Trial Register (NTR2975) and EudraCT (2011-002287-24).

Major Thromboembolic Complications in Liver Transplantation: The Role of Rotational Thromboelastometry and Cryoprecipitate Transfusion

BACKGROUND

Although hemorrhage is a major concern during liver transplantation (LT), the risk for thromboembolism is well recognized. Implementation of rotational thromboelastometry (ROTEM) has been associated with the increased use of cryoprecipitate; however, the role of ROTEM-guided transfusion strategy and cryoprecipitate administration in the development of major thromboembolic complications (MTCs) has never been documented.

METHODS

We conducted a study on patients undergoing LT before and after the implementation of ROTEM. We defined MTC as intracardiac thrombus, pulmonary embolism, hepatic artery thrombosis, and ischemic stroke in 30 d after LT. We used a propensity score to match patients during the 2 study periods.

RESULTS

Among 2330 patients, 119 (4.9%) developed MTC. The implementation of ROTEM was significantly associated with an increase in cryoprecipitate use (1.1 ± 1.1 versus 2.9 ± 2.3 units, P < 0.001) and MTC (4.2% versus 9.5%, P < 0.001). Further analysis demonstrated that the use of cryoprecipitate was an independent risk factor for MTC (odds ratio 1.1, 95% confidence interval 1.04-1.24, P = 0.003). Patients with MTC had significantly lower 1-y survival.

CONCLUSIONS

Our study suggests that the implementation of ROTEM and the use of cryoprecipitate play significant roles in the development of MTC in LT. The benefits and risks of cryoprecipitate transfusion should be carefully evaluated before administration.

Pediatric Fibrinogen PART II-Overview of Indications for Fibrinogen Use in Critically Ill Children

Bleeding is frequently seen in critically ill children and is associated with increased morbidity and mortality. Fibrinogen is an essential coagulation factor for hemostasis and hypofibrinogenemia is an important risk factor for bleeding in pediatric and adult settings. Cryoprecipitate and fibrinogen concentrate are often given to critically ill children to prevent bleeding and improve fibrinogen levels, especially in the setting of surgery, trauma, leukemia, disseminated intravascular coagulopathy, and liver failure. The theoretical benefit of fibrinogen supplementation to treat hypofibrinogenemia appears obvious, yet the evidence to support fibrinogen supplementation in children is sparce and clinical indications are poorly defined. In addition, it is unknown what the optimal fibrinogen replacement product is in children and neonates or what the targets of treatment should be. As a result, there is considerable variability in practice. In this article we will review the current pediatric and applicable adult literature with regard to the use of fibrinogen replacement in different pediatric critical care contexts. We will discuss the clinical indications for fibrinogen supplementation in critically ill children and the evidence to support their use. We summarize by highlighting current knowledge gaps and areas for future research.

Trigger and Target for Fibrinogen Supplementation Using Thromboelastometry (ROTEM) in Patients Undergoing Open Thoraco-Abdominal Aortic Aneurysm Repair

OBJECTIVE

To determine the relationship between the value of fibrinogen assessed by the FIBTEM clot amplitude at 10 minutes (A10 FIBTEM) measured on admission to the intensive care unit (ICU) and the amount of drainage output at 24 hours, to investigate whether the A10 FIBTEM predicts severe bleeding (SB), and to define A10 FIBTEM thresholds to prevent (trigger) and treat (target) severe bleeding by fibrinogen supplementation.

METHODS

In a single centre, retrospective observational study, 166 patients underwent elective open thoraco-abdominal aortic aneurysm (TAAA) repair between March 2016 and January 2019. Exclusion criteria were emergency, congenital, or acquired coagulopathy, or administration of P₂Y₁₂ inhibitor antiplatelet agents in the five days before surgery. All patients were managed intra-operatively and post-operatively according to a rotational thromboelastometry driven transfusion protocol. The principal endpoint was a composite outcome, which included bleeding, large volume transfusion, and re-operation.

RESULTS

FIBTEM clot amplitude after 10 minutes measured on ICU admission and post-operative bleeding at 24 hours showed an inverse linear relationship (R² = .03; p = .026). Performance of A10 FIBTEM in predicting SB evaluated by Receiving Operating Curve analysis showed an area under the curve of 0.63 (95% CI 0.56 - 0.70; p = .026) with a best cutoff of 9 mm. An A10 FIBTEM of 3 mm was the cutoff associated with a positive predictive value of 50%, while an A10 FIBTEM of 9 mm showed a negative predictive value of 92%. On multivariable analysis, an A10 FIBTEM ≤ 3 mm remained independently associated with SB.

CONCLUSION

The present investigation shows for the first time in a population undergoing open TAAA repair that an A10 FIBTEM ≤ 3mm on ICU admission is associated with post-operative severe bleeding. Trigger and target values for fibrinogen supplementation, based on A10 FIBTEM, have been provided. The transferability and reliability of these cutoff values require further study.

Current perspective on fibrinogen concentrate in critical bleeding

INTRODUCTION

. Massive hemorrhage continues to be a treatable cause of death. Its management varies from prefixed ratio-driven administration of blood components to goal-directed therapy based on point-of-care testing and administration of coagulation factor concentrates.

AREAS COVERED

. We review the current role of fibrinogen concentrate (FC) for the management of massive hemorrhage, either administered without coagulation testing in life-threatening hemorrhage, or within an algorithm based on viscoelastic hemostatic assays and plasma fibrinogen level. We identified relevant guidelines, meta-analyzes, randomized controlled trials, and observational studies that included indications, dosage, and adverse effects of FC, especially thromboembolic events.

EXPERT OPINION

. Moderate- to high-grade evidence supports the use of FC for the treatment of severe hemorrhage in trauma and cardiac surgery; a lower grade of evidence is available for its use in postpartum hemorrhage and end-stage liver disease. Pre-emptive FC administration in non-bleeding patients is not recommended. FC should be administered early, in a goal-directed manner, guided by early amplitude of clot firmness parameters (A5- or A10-FIBTEM) or hypofibrinogenemia. Further investigation is required into the early use of FC, as well as its potential advantages over cryoprecipitate, and whether or not its administration at high doses leads to a greater risk of adverse events.

Coagulation testing and management in liver disease patients

PURPOSE OF REVIEW

The present article aims to provide clinicians with an overview of coagulation testing in individuals with liver disease, to discuss available procoagulants and the rationale for their use, and to provide management strategies in a variety of common clinical scenarios.

RECENT FINDINGS

Clinicians and researchers are gaining an increased understanding of the shortfalls of assessing bleeding risk using traditional tests of coagulation. The use of global tests of clot formation, including viscoelastic testing and thrombin generation analysis, continues to evolve and guide the management of these patients.

SUMMARY

Abnormal coagulation testing in individuals with cirrhosis leads to a variety of difficult clinical scenarios that can be challenging for practitioners. With advanced liver disease, changes in the traditional tests of hemostasis such as the international normalized ratio reflect decreased synthesis of procoagulant factors but do not capture concomitant decreases in anticoagulant factors. In this setting, transfusion thresholds targeting platelet and fibrinogen goals may provide an effective strategy to optimize clot formation. Global tests of clot formation provide practical information to clinicians and can help guide decision making, although optimal target levels have not been validated.

Assessment and management of coagulopathy in critically-ill patients with liver failure

PURPOSE OF REVIEW

This review provides insight into our current understanding of the pathophysiology and treatment of coagulopathy associated with liver failure, and bleeding risk assessment.

RECENT FINDINGS

Patients with end-stage liver disease (ESLD) have a rebalanced coagulation profile and are at risk for both excessive clotting and bleeding. Hypercoagulability is associated with profound endothelial dysfunction and an increased concentration of liver-independent coagulation factors. Because of this rebalanced coagulation profile, standard laboratory tests have been demonstrated to be ineffective in either predicting and/or guiding the management of coagulopathy. Viscoelastic testing, however, is able to provide a dynamic assessment of clot formation in whole blood and has been demonstrated to be invaluable in both monitoring and management of coagulation problems associated with liver failure. More recently, there is increasing interest in thrombin generation tests to monitor coagulation in patients with ESLD.Multiple institutional protocols for prophylaxis and treatment of ESLD-related thromboses have been developed. High-quality studies evaluating these approaches are lacking.

SUMMARY

Patients with ESLD are at risk for excessive bleeding and clotting. Treatment of any significant coagulopathy should not be based solely on standard laboratory tests. Thrombosis prophylaxis has to be considered in susceptible populations.

Management of Hepatic Coagulopathy in Bleeding and Nonbleeding Patients: An Evidence-Based Review

Patients with varying degrees of hepatic dysfunction often present with presumed bleeding diathesis based on interpretation of routine measures of coagulation (prothrombin time [PT], international normalized ratio [INR], and activated partial thromboplastin time). However, standard markers of coagulation do not reflect the actual bleeding risk in this population and may lead to inappropriate administration of hemostatic agents and blood products. The concept of "rebalanced hemostasis" explains both the risk of bleeding and clotting seen in patients with liver dysfunction. The role of pharmacologic agents and blood products for prevention of bleeding during high-risk procedures and treatment of clinically significant bleeding remains unclear. Viscoelastic measurements of the clotting cascade provide information about platelets, fibrinogen/fibrin polymerization, coagulation factors, and fibrinolysis that might better represent hemostasis in vivo and may better inform management strategies. Due to the paucity of available data, firm recommendations for the use of blood products and pharmacologic agents in patients with hepatic coagulopathies are lacking, and thus, these products should not be routinely administered. Traditional laboratory tests such as PT/INR should not be the sole determinant of potential interventions. Rather, clinicians should assess factors such as the severity of bleed or bleeding risk of the procedure, the patient's risk of thromboembolism, and the strength of available evidence for specific agents and blood products to guide decision-making.

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

Rotational thromboelastometry (ROTEM) is a point-of-care viscoelastic method and enables to assess viscoelastic profiles of whole blood in various clinical settings. ROTEM-guided bleeding management has become an essential part of patient blood management (PBM) which is an important concept in improving patient safety. Here, ROTEM testing and hemostatic interventions should be linked by evidence-based, setting-specific algorithms adapted to the specific patient population of the hospitals and the local availability of hemostatic interventions. Accordingly, ROTEM-guided algorithms implement the concept of personalized or precision medicine in perioperative bleeding management (‘theranostic’ approach). ROTEM-guided PBM has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and health care costs. Accordingly, several randomized-controlled trials, meta-analyses, and health technology assessments provided evidence that using ROTEM-guided algorithms in bleeding patients resulted in improved patient’s safety and outcomes including perioperative morbidity and mortality. However, the implementation of ROTEM in the PBM concept requires adequate technical and interpretation training, education and logistics, as well as interdisciplinary communication and collaboration.

Perioperative hemostatic management in the cirrhotic patient: a position paper on behalf of the Liver Intensive Care Group of Europe (LICAGE)

Recent data demonstrated that amongst patients undergoing elective surgery the prevalence of cirrhosis is 0.8% equating to approximately 25 million cirrhotic patients undergoing surgery each year worldwide. Overall, the presence of cirrhosis is independently associated with 47% increased risk of postoperative complications and over two and a half-increased risk of in-hospital mortality in patients undergoing elective surgery. In particular, perioperative patients with chronic liver disease have long been assumed to have a major bleeding risk on the basis of abnormal results for standard tests of hemostasis. However, recent evidence outlined significant changes to traditional knowledge and beliefs and, nowadays, with more sophisticated laboratory tests, it has been shown that patients with chronic liver disease may be in hemostatic balance as a result of concomitant changes in both pro- and antihemostatic pathways. The aim of this paper endorsed by the Liver Intensive Care Group of Europe was to provide an up-to-date overview of coagulation management in perioperative patients with chronic liver disease focusing on patient blood management, monitoring of hemostasis, and current role of hemostatic agents.

Pro-coagulant haemostatic factors for the prevention and treatment of bleeding in people without haemophilia

BACKGROUND

Some hospital patients may be at risk of or may present with major bleeding. Abnormalities of clotting (coagulation) are often recorded in these people, and the traditional management has been with transfusions of blood components, either to prevent bleeding (prophylactic) or to treat bleeding (therapeutic). There is growing interest in the use of targeted therapies with specific pro-coagulant haemostatic (causing bleeding to stop and to keep blood within a damaged blood vessel) factor concentrates in place of plasma.

OBJECTIVES

To assess the effects and safety of pro-coagulant haemostatic factors and factor concentrates in the prevention and treatment of bleeding in people without haemophilia.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (2018, issue 3), MEDLINE (from 1948), Embase (from 1974), CINAHL (from 1938), PubMed (publications in process to 18 April 2018), PROSPERO, Transfusion Evidence Library (from 1950), LILACS (from 1980), IndMED (from 1985), KoreaMed (from 1934), Web of Science Conference Proceedings Citation Index (from 1990) and ongoing trial databases to 18 April 2018.

SELECTION CRITERIA

We included RCTs that compared intravenous administration of a pro-coagulant haemostatic factor concentrate, either with placebo, current best or standard treatment, or another pro-coagulant haemostatic factor concentrate for prevention or treatment of bleeding. There was no restriction on the types of participants. We excluded studies of desmopressin, tranexamic acid and aminocaproic acid and use of pro-coagulant haemostatic factors for vitamin K over-anticoagulation.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodological procedures.

MAIN RESULTS

We identified 31 RCTs with 2392 participants and 22 ongoing trials. There were 13 therapeutic RCTs that randomised 1057 participants (range from 20 to 249 participants) and 18 prophylactic trials that randomised 1335 participants (range 20 to 479 participants). The pro-coagulant haemostatic factor concentrate was fibrinogen in 23 trials, Factor XIII in seven trials and pro-thrombin complex concentrates (PCC) in one trial.Seventeen trials had industrial funding or support, eight studies either did not declare their funding or were unclear about their source of funding and six studies declared non-industrial funding sources.Certainty in the evidence and included study biasOur certainty in the evidence, using GRADE criteria, ranged from very low to high across all outcomes. We assessed most outcomes as being of low certainty. Risks of bias were a concern in many of the RCTs; randomisation methodology was unclear in 15 RCTs, with allocation concealment unclear in 14 RCTs and at high risk of bias in five RCTs. The blinding status of outcome assessors was unclear in 13 RCTs and at high risk of bias in five RCTs, although most outcomes in these trials were objective and not prone to observer bias. Study personnel were often unblinded or insufficient information was available to assess their level of blinding (five RCTs were at unclear risk and seven at high risk of bias).Primary outcomesAll-cause mortality was reported by 21 RCTs, arterial thromboembolic events by 22 RCTs, and venous thromboembolic events by 21 RCTs.Fibrinogen concentrate: prophylactic trials with inactive comparator (nine RCTs)The trials had heterogeneous clinical settings and outcome time points, so we did not pool the data. Compared to placebo, there was no evidence that prophylactic fibrinogen concentrate reduced all-cause mortality (4 RCTs; 248 participants). Compared to inactive comparators there was low- to moderate-quality evidence that prophylactic fibrinogen concentrate did not increase the risk of arterial or venous thromboembolic complications (7 RCTs; 398 participants).Fibrinogen concentrate: prophylactic trials with active comparator (two RCTs)There was no mortality or incidence of thromboembolic events in these two RCTs (with 57 participants).Fibrinogen concentrate: therapeutic trials with inactive comparator (eight RCTs)The trials had heterogeneous surgical settings and outcome time points, so we pooled data for subgroups only. Compared to an inactive comparator, there was no evidence (quality ranging from low to high) that fibrinogen concentrate reduced all-cause mortality in actively bleeding participants (7 RCTs; 724 participants). Compared to inactive comparators there was no evidence that the use of fibrinogen concentrate in active bleeding increased arterial (7 RCTs; 607 participants) or venous (6 RCTs; 562 participants) thromboembolic events.Fibrinogen concentrate: therapeutic trials with active comparator (four RCTs)We did not pool the outcome data, as they were not measured at comparable time points. Compared to other active pro-coagulant agents, there was no evidence (very low to moderate quality) that fibrinogen concentrate reduced all-cause mortality in actively bleeding participants (4 RCTs; 220 participants). There was no evidence that fibrinogen concentrate increased the risk of arterial (3 RCTs; 126 participants) or venous (4 RCTs; 220 participants) thromboembolic events.FactorXIII: Prophylactic trials with inactive comparator (six trials)The trials were heterogeneous in their surgical settings and time points for outcome analysis, so we pooled data for subgroups only. Compared to an inactive comparator, there was no evidence that prophylactic Factor XIII reduced all-cause mortality (5 RCTs; 414 participants). There was no evidence (very low to low quality) of a difference in the arterial or venous event rate between Factor XIII and inactive comparators (4 trials; 354 participants).FactorXIII: therapeutic trials with inactive comparator (one trial)There was no mortality or incidence of thromboembolic events in this trial.Prothrombin complex concentrate (PCC): prophylactic trials with inactive comparator (one trial)There was no evidence (moderate quality) that PCC reduced all-cause mortality (1 trial; 78 participants). No thromboembolic complications were reported in this trial.

AUTHORS' CONCLUSIONS

The paucity of good-quality comparable evidence precludes the drawing of conclusions for clinical practice. Further research is required to determine the risk-to-benefit ratio of these interventions. The sample sizes of future RCTs would need to be greatly increased to detect a reduction in mortality or thromboembolic events between treatment arms. To improve consistency in outcome reporting, the development of core outcome sets is essential and may help address a number of the limitations identified in this review.

Do we still need cryoprecipitate? Cryoprecipitate and fibrinogen concentrate as treatments for major hemorrhage - how do they compare?

INTRODUCTION

Major hemorrhage is a source of significant mortality and morbidity worldwide. Identification and characterization of coagulation impairment associated with major hemorrhage has suggested a key role for fibrinogen deficiency, however the optimum mode of replacement of fibrinogen remains unclear, and standardized major hemorrhage protocols may overlook context-dependent variations in individual patients' clotting derangement. Areas covered: This paper examines the current practice and evidence regarding the role of different modes of fibrinogen replacement in major hemorrhage in 3 distinct clinical settings: trauma, obstetric hemorrhage, and gastrointestinal hemorrhage with associated liver disease. A literature search was carried out electronically using Athens access to the National Health Service evidence health information resources, primarily PubMed and Google Scholar. Expert commentary: Two key questions need to be addressed. First, what is the role of concentrated fibrinogen (by comparison to no fibrinogen), and second, which concentrated source or product is more effective (or cost-effective)? Current practice and concept is derived largely from small pilot trials in the trauma setting, but results from larger studies are awaited. More comparative data on changes to clotting profiles in different groups of bleeding patients are needed to help delineate differences and guide interventional treatment studies.

Coagulation Management During Liver Transplantation: Use of Fibrinogen Concentrate, Recombinant Activated Factor VII, Prothrombin Complex Concentrate, and Antifibrinolytics

Coagulation management, and transfusion practice in liver transplantation (LT) have been evolving in the recent years due to better understanding of coagulation abnormalities in end-stage liver disease, and clinical management of LT patients. Avoidance of allogeneic blood components is feasible in some patients, but multi-modal coagulation therapies may be necessary in others who develop complex coagulopathy due to hemorrhage, hemodilution, hypothermia, and acid-base disturbances. Transfusions of plasma and cryoprecipitate remain to be the mainstay therapy for procoagulant factor replacement during LT. Clinical efficacy and safety of these products are limited by logistic issues (eg, thawing), and mostly noninfectious complications. Considering potential alternatives to conventional transfusion is thus important to improve hemostatic resuscitation in complex LT cases. The present review is mainly focused on procoagulant properties of plasma and platelet transfusion, and currently available plasma-derived and recombinant factor concentrates, and antifibrinolytic agents in LT patients. The role of viscoelastic coagulation tests to guide specific component therapies will be also discussed.

Value of Preoperative Hemostasis Testing in Patients with Liver Disease for Perioperative Hemostatic Management

Preoperative hemostasis testing may have limited use in patients with liver disease, and an abnormal platelet count, prothrombin time, activated partial thromboplastin time, and fibrinogen level should not trigger prophylactic transfusion of blood product components.