Analyzing and modeling massive transfusion strategies and the role of fibrinogen-How much is the patient actually receiving?

BACKGROUND

Hemorrhage is a leading cause of preventable death in trauma, cardiac surgery, liver transplant, and childbirth. While emphasis on protocolization and ratio of blood product transfusion improves ability to treat hemorrhage rapidly, tools to facilitate understanding of the overall content of a specific transfusion strategy are lacking. Medical modeling can provide insights into where deficits in treatment could arise and key areas for clinical study. By using a transfusion model to gain insight into the aggregate content of massive transfusion protocols (MTPs), clinicians can optimize protocols and create opportunities for future studies of precision transfusion medicine in hemorrhage treatment.

METHODS

The transfusion model describes the individual round and aggregate content provided by four rounds of MTP, illustrating that the total content of blood elements and coagulation factor changes over time, independent of the patient's condition. The configurable model calculates the aggregate hematocrit, platelet concentration, percent volume plasma, total grams and concentration of citrate, percent volume anticoagulant and additive solution, and concentration of clotting factors: fibrinogen, factor XIII, factor VIII, and von Willebrand factor, provided by the MTP strategy.

RESULTS

Transfusion strategies based on a 1:1:1 or whole blood foundation provide between 13.7 and 17.2 L of blood products over four rounds. Content of strategies varies widely across all measurements based on base strategy and addition of concentrated sources of fibrinogen and other key clotting factors.

DISCUSSION

Differences observed between modeled transfusion strategies provide key insights into potential opportunities to provide patients with precision transfusion strategy.

Shock Index for Early Detection of Low Plasma Fibrinogen in Trauma: A Prospective Observational Cohort Pilot Study

Shock index (a ratio between heart rate and systolic blood pressure) predicts transfusion requirements and the need for haemostatic resuscitation in severe trauma patients. In the present study, we aimed to determine whether prehospital and on-admission shock index values can be used to predict low plasma fibrinogen in trauma patients. Between January 2016 and February 2017, trauma patients admitted from the helicopter emergency medical service into two large trauma centres in the Czech Republic were prospectively assessed for demographic, laboratory and trauma-associated variables and shock index at scene, during transport and at admission to the emergency department. Hypofibrinogenemia defined as fibrinogen plasma level of 1.5 g·L^-l was deemed as a cut-off for further analysis. Three hundred and twenty-two patients were screened for eligibility. Of these, 264 (83%) were included for further analysis. The hypofibrinogenemia was predicted by the worst prehospital shock index with the area under the receiver operating characteristics curve (AUROC) of 0.79 (95% CI 0.64-0.91) and by the admission shock index with AUROC of 0.79 (95% CI 0.66-0.91). For predicting hypofibrinogenemia, the prehospital shock index ≥ 1 has 0.5 sensitivity (95% CI 0.19-0.81), 0.88 specificity (95% CI 0.83-0.92) and a negative predictive value of 0.98 (0.96-0.99). The shock index may help to identify trauma patients at risk of hypofibrinogenemia early in the prehospital course.

The role of fibrinogen in postpartum hemorrhage

Postpartum hemorrhage (PPH) is the leading cause of maternal death worldwide (WHO), with almost 60000 deaths annually. Pregnancy is a prothrombotic state with increased levels of several coagulation factors to protect the parturient from bleeding problems during delivery. Fibrinogen has a significant role in coagulation and bleeding. Studies have pointed out that lower fibrinogen levels before delivery, but also at the initiation of PPH, are predictive of major hemorrhage. Early, the goal-directed fibrinogen concentrate therapy might be very useful in a subgroup of patients with serious PPH. This review aims to summarize the current literature on fibrinogen during PPH.

Latest advances in postpartum hemorrhage management

Hemorrhage is the leading cause of maternal mortality worldwide. A maternal health priority is improving how healthcare providers prevent and manage postpartum hemorrhage (PPH). Because anesthesiologists can help facilitate how hospitals develop approaches for PPH prevention and anticipatory planning, we review the potential utility of PPH risk-assessment tools, bundles, and protocols. Anesthesiologists rely on clinical and diagnostic information for initiating and evaluating medical management. Therefore, we review modalities for measuring blood loss after delivery, which includes visual, volumetric, gravimetric, and colorimetric approaches. Point-of-care technologies for assessing changes in central hemodynamics (ultrasonography) and coagulation profiles (rotational thromboelastometry and thromboelastography) are also discussed. Anesthesiologists play a critical role in the medical and transfusion management of PPH. Therefore, we review blood ordering and massive transfusion protocols, fixed-ratio vs. goal-directed transfusion approaches, coagulation changes during PPH, and the potential clinical utility of the pharmacological adjuncts, tranexamic acid, and fibrinogen concentrate.

Administration of fibrinogen concentrate combined with prothrombin complex maintains hemostasis in children undergoing congenital heart repair (a long-term propensity score-matched study)

Background

Bleeding is a common problem in children with congenital heart disease undergoing major cardiac surgery requiring cardiopulmonary bypass (CPB). Little is known about optimal management with blood products.

Objective

To investigate clinical outcome and hemostatic effects of fibrinogen concentrate (FC) in combination with prothrombin complex concentrate (PCC) versus standard treatment with fresh frozen plasma (FFP) in children undergoing cardiac surgery.

Methods

For this single‐institution cohort study, data on 525 children were analyzed. Propensity score matching in 210 children was applied to reduce the impact of various baseline characteristics.

Results

Three children treated with FC/PCC developed surgical site bleeding requiring surgical revision. One child developed central venous line‐related thrombosis. Blood loss through chest tube drainage was independent of FC/PCC. Coagulation abnormalities were not present in any of these children. Time to extubation and ICU stay did not differ. In the FC/PCC group, children received (median, Q1, Q3) 52 mg/kg (32, 83) FC and 28IU/kg (13, 44) PCC. Fibrinogen concentration was comparable at baseline. On admission to the ICU, fibrinogen was higher in children receiving FC/PCC, namely, 232 mg/dL (196, 280), than in children receiving FFP (186 mg/dL, 149, 224; P < .001). On discharge from the ICU, values did not differ ((FC/PCC 416 mg/dL (288, 501)), non‐FC/PCC 418 mg/dL (272, 585; P = 1.000)).

Conclusion

FC/PCC was well tolerated and permitted hemostasis to be maintained, even in the very young. We were not able to detect a signal for inferiority of this treatment. We conclude that FC/PCC can safely replace FFP.

Fibrinogen Replacement in Haemostatic Resuscitation: Dose, Laboratory Targets and Product Choice

Fibrinogen is a key coagulation protein that is necessary for the formation of stable clots. Fibrinogen levels have been reported to be one of the first to fall during major haemorrhage reflecting consumption, dilution and fibrinogenolysis. Its role in acquired major haemorrhage, both in relation to the contribution it plays to the coagulopathy of major bleeding that can exacerbate bleeding and how effective fibrinogen supplementation can be at improving clinical outcomes, has received a great deal of attention over the last 10 - 15 years. This commentary focuses on just three of the more recent publications from the last 5 years that provide some of the evidence behind how we can think about fibrinogen as a haemostatic treatment for acquired major haemorrhage and how we can use the laboratory thresholds to guide therapy.

First-Line Administration of Fibrinogen Concentrate in the Bleeding Trauma Patient: Searching for Effective Dosages and Optimal Post-Treatment Levels Limiting Massive Transfusion-Further Results of the RETIC Study

Fibrinogen supplementation is recommended for treatment of severe trauma hemorrhage. However, required dosages and aimed for post-treatment fibrinogen levels remain a matter of discussion. Within the published RETIC study, adult patients suffering trauma-induced coagulopathy were randomly assigned to receive fibrinogen concentrate (FC) as first-line (n = 50) or crossover rescue (n = 20) therapy. Depending on bodyweight, a single dose of 3, 4, 5, or 6 g FC was administered and repeated if necessary (FibA10 < 9 mm). The dose-dependent response (changes in plasma fibrinogen and FibA10) was analyzed. Receiver operating characteristics (ROC) analysis regarding the need for massive transfusion and correlation analyses regarding fibrinogen concentrations and polymerization were performed. Median FC single doses amounted to 62.5 (57 to 66.66) mg·kg⁻¹. One FC single-dose sufficiently corrected fibrinogen and FibA10 (median fibrinogen 213 mg·dL⁻¹, median FibA10 11 mm) only in patients with baseline fibrinogen above 100 mg·dL⁻¹ and FibA10 above 5 mm, repeated dosing was required in patients with lower baseline fibrinogen/FibA10. Fibrinogen increased by 83 or 107 mg·dL⁻¹ and FibA10 by 4 or 4.5 mm after single or double dose of FC, respectively. ROC curve analysis revealed post-treatment fibrinogen levels under 204.5 mg·dL⁻¹ to predict the need for massive transfusion (AUC 0.652; specificity: 0.667; sensitivity: 0.688). Baseline fibrinogen/FibA10 levels should be considered for FC dosing as only sufficiently corrected post-treatment levels limit transfusion requirements.

Case Report: Life-Threatening Post-operative Hemorrhage in Klippel-Trenaunay Syndrome Associated With Hypofibrinogenemia

Klippel–Trenaunay Syndrome (KTS) is a rare congenital disorder, characterized by venous and lymphatic malformations of the skin, soft tissue, and bone, causing limb hypertrophy. Although, a ruptured hemorrhagic corpus luteum is a rare condition in women of reproductive age, it can result in lethal outcomes. Here, we have described a patient with KTS and hypofibrinogenemia who went through recurrent lethal postoperative bleeding due to a ruptured hemorrhagic corpus luteum. This case suggested that conservative therapy might be the first choice and effective therapy for the patients with KTS, who suffered from bleeding complications of surgical therapy.

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.

Effects of pathogen reduction technology and storage duration on the ability of cryoprecipitate to rescue induced coagulopathies in vitro

Background

Fibrinogen concentrates and cryoprecipitate are currently used for fibrinogen supplementation in bleeding patients with dysfibrinogenemia. Both products provide an abundant source of fibrinogen but take greater than 10 min to prepare for administration. Fibrinogen concentrates lack coagulation factors (i.e., factor VIII [FVIII], factor XIII [FXIII], von Willebrand factor [VWF]) important for robust hemostatic function. Cryoprecipitate products contain these factors but have short shelf lives (<6 h). Pathogen reduction (PR) of cryoprecipitate would provide a shelf‐stable immediately available adjunct containing factors important for rescuing hemostatic dysfunction.

Study Design and Methods

Hemostatic adjunct study products were psoralen‐treated PR‐cryoprecipitated fibrinogen complex (PR‐Cryo FC), cryoprecipitate (Cryo), and fibrinogen concentrates (FibCon). PR‐Cryo FC and Cryo were stored for 10 days at 20–24°C. Adjuncts were added to coagulopathies (dilutional, 3:7 whole blood [WB]:normal saline; or lytic, WB + 75 ng/ml tissue plasminogen activator), and hemostatic function was assessed by rotational thromboelastometry and thrombin generation.

Results

PR of cryoprecipitate did not reduce levels of FVIII, FXIII, or VWF. PR‐Cryo FC rescued dilutional coagulopathy similarly to Cryo, while generating significantly more thrombin than FibCon, which also rescued dilutional coagulopathy. Storage out to 10 days at 20–24°C did not diminish the hemostatic function of PR‐Cryo FC.

Discussion

PR‐Cryo FC provides similar and/or improved hemostatic rescue compared to FibCon in dilutional coagulopathies, and this rescue ability is stable over 10 days of storage. In hemorrhaging patients, where every minute delay is associated with a 5% increase in mortality, the immediate availability of PR‐Cryo FC has the potential to improve outcomes.

Emergency administration of fibrinogen concentrate for hemorrhage: A protocol for systematic review and meta-analysis

INTRODUCTION

The occurrence of massive hemorrhages in various emergency situations increases the need for blood transfusions and the risk of mortality. Use of fibrinogen concentrate (FC) may increase plasma fibrinogen levels more rapidly than the use of fresh-frozen product or cryoprecipitate. However, thus far, the efficacy of FC in significantly improving the risk of mortality and significantly reducing transfusion requirements has not been effectively demonstrated in several systematic reviews and meta-analyses.

METHODS AND ANALYSIS

We will conduct a systematic review and meta-analysis of FC for hemorrhages in emergency situations. We will include controlled trials, but will exclude randomized controlled trials in elective surgeries. We will include patients with hemorrhages in emergency situations. Intervention will be emergency supplementation of FC. The control group will be administered with ordinal transfusion or placebo. The primary outcome of the study is in-hospital mortality.We will search in electronic databases such as MEDLINE (PubMed), Web of Science, and the Cochrane Central Register of Controlled Trials. Two reviewers will independently screen the title and abstract, retrieve the full text of the selected articles, and extract the essential data. We will apply uniform criteria for evaluating the risk of bias associated with individual randomized controlled trial based on the Cochrane risk of bias tool. Values of the risk ratio will be expressed as a point estimate with 95% confidence intervals (CIs). Data of continuous variables will be expressed as the mean difference along with their 95% CIs and P values. We will assess the strength of evidence using the Grading of Recommendations Assessment, Development and Evaluation approach.

ETHICS AND DISSEMINATION

This systematic review will provide physicians with updated information on the efficacy and safety of using FC for hemorrhage in emergency settings. Approval from the ethics board and patient consent were not required in our study.This study protocol has been funded through a protocol registry. The registry number is UMIN000041598.

Hemostatic defects in massive transfusion: an update and treatment recommendations

INTRODUCTION

Acute hemorrhage is a global healthcare issue, and remains the leading preventable cause of death in trauma. Acute severe hemorrhage can be related to traumatic, peripartum, gastrointestinal, and procedural causes. Hemostatic defects occur early in patients requiring massive transfusion. Early recognition and treatment of hemorrhage and hemostatic defects are required to save lives and to achieve optimal patient outcomes.

AREAS COVERED

This review discusses current evidence and trials aimed at identifying the optimal treatment for hemostatic defects in hemorrhage and massive transfusion. Literature search included PubMed and Embase.

EXPERT OPINION

Patients with acute hemorrhage requiring massive transfusion commonly develop coagulopathy due to specific hemostatic defects, and accurate diagnosis and prompt correction are required for definitive hemorrhage control. Damage control resuscitation and massive transfusion protocols are optimal initial treatment strategies, followed by goal-directed individualized resuscitation using real-time coagulation monitoring. Distinct phenotypes exist in trauma-induced coagulopathy, including 'Bleeding' or 'Thrombotic' phenotypes, and hyperfibrinolysis vs. fibrinolysis shutdown. The trauma 'lethal triad' (hypothermia, coagulopathy, acidosis) has been updated to the 'lethal diamond' (including hypocalcemia). A number of controversies in optimal management exist, including whole blood vs. component therapy, use of factor concentrates vs. blood products, optimal use of tranexamic acid, and prehospital plasma and tranexamic acid administration.

Pediatric Fibrinogen PART I-Pitfalls in Fibrinogen Evaluation and Use of Fibrinogen Replacement Products in Children

Fibrinogen is a key coagulation protein, playing a critical role in hemostasis. It is the first factor to decrease to critical levels during bleeding. Hypofibrinogenemia is an important risk factor for bleeding in clinical settings, including pediatric surgery. Yet, the optimal measurement of fibrinogen levels is subject to debate, as is the critical threshold for intervention. Fibrinogen replacement may be provided by cryoprecipitate and fibrinogen concentrate. Whilst both products contain fibrinogen, they are not equivalent, each has its own advantages and disadvantages, especially for pediatric use. Unfortunately, medical literature to support fibrinogen replacement in children is limited. In this article we review the current diagnostic tools to measure fibrinogen, with respect to their use in the pediatric critical care setting. Secondly, we evaluate the different fibrinogen replacement therapies, focusing on cryoprecipitate and fibrinogen concentrate and examine their individual product characteristics, associated risks and benefits, different dosing strategies and specific pitfalls for use in children. We summarize by highlighting current knowledge gaps and areas for future research.

Patient Blood Management in cardiac anesthesia

The accessibility to blood products is increasingly limited worldwide. Approximately half of the blood products is utilized in cardiovascular surgery. The rational use of the available blood products has therefore paramount importance in everyday practice. In the present publication, the possible methods of blood-product sparing in cardiac surgery are summarized. We have emphasized the principles of the treatment and the prevention of severe peri-operative bleeding. Orv Hetil. 2020; 161(37): 1579-1587.

Dynamics of Platelet Counts in Major Trauma: The Impact of Haemostatic Resuscitation and Effects of Platelet Transfusion-A Sub-Study of the Randomized Controlled RETIC Trial

Although platelets play a central role in haemostasis, the dynamics of platelet counts during haemostatic resuscitation, the response to platelet transfusion, and effects on clinical outcome are poorly described for trauma patients. As a sub-study of the already published randomized controlled RETIC Study "Reversal of Trauma-induced Coagulopathy using First-line Coagulation Factor Concentrates or Fresh-Frozen Plasma" trial, we here analysed whether the type of first-line haemostatic resuscitation influences the frequency of platelet transfusion and determined the effects of platelet transfusion in coagulopathic patients with major trauma. Patients randomly received first-line plasma (FFP) or coagulation factor concentrates (CFC), mainly fibrinogen concentrate. In both groups, platelets were transfused to maintain platelet counts between 50 and 100 × 10⁹ /L. Transfusion rates were significantly higher in the FFP (n = 44) vs. CFC (n = 50) group (FFP 47.7% vs. CFC 26%); p = 0.0335. Logistic regression analysis adjusted for the stratification variables injury severity score (ISS) and brain injury confirmed that first-line FFP therapy increases the odds for platelet transfusion (odds ratio (OR) 5.79 (1.89 to 20.62), p = 0.0036) and this effect was larger than a 16-point increase in ISS (OR 4.33 (2.17 to 9.74), p =0.0001). In conclusion, early fibrinogen supplementation exerted a platelet-saving effect while platelet transfusions did not substantially improve platelet count and might contribute to poor clinical outcome.

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.

The prophylactic use of fibrinogen concentrate in high-risk cardiac surgery

BACKGROUND

Perioperative blood loss is a major contributor to morbidity and mortality in cardiac surgery. Plasma fibrinogen levels play an essential role in hemostasis and deplete quickly during hemorrhage. The objective of this study was to determine whether prophylactic fibrinogen concentrate administration lowers overall blood product transfusion requirements in high-risk cardiac surgery in patients with low fibrinogen plasma levels.

METHODS

The study was performed in a prospective, randomized, and double-blinded design. The investigation included 62 patients undergoing elective, high-risk cardiac surgery. After weaning from cardiopulmonary bypass and reversal of heparin patients received either fibrinogen concentrate or placebo. The primary outcome variable was overall blood product usage 24 hours after intervention.

RESULTS

The fibrinogen group received numerically fewer total units of blood products than the placebo group, but the difference was not statistically or clinically significant (for groups n = 27; n = 29 and 19 vs 37 units, respectively, P = .908). The overall transfusion rate in both groups was significantly lower than the institutional average suggested (fibrinogen group 26%, placebo group 28%). The fibrinogen group showed significantly higher fibrinogen levels (2.38 vs 1.83 g/L (end of surgery), P < .001; 3.33 vs 2.68 g/L (12 hours after intervention), P = .003) and improved viscoelastic coagulation parameters (FIBTEM MCF, 27 vs 23 mm, P = .022).

CONCLUSION

This randomized, controlled trial demonstrates that point-of-care guided and prophylactic treatment with fibrinogen concentrate does not reduce transfusion of blood products in a setting of unexpectedly low transfusion rate as tested in this cohort, but may improve coagulation parameters in the setting of high-risk cardiac surgery.

New Hemostatic Agents: Perioperative Anesthetic Considerations

AIM

Pharmacologic agents with procoagulant effects and antidotes against antithrombotic drugs play an important role in the prevention and management of perioperative coagulopathic bleeding. The aim of this narrative review is knowledge transfer from new and renewed hemostatic agents to anesthesiologists and other physicians involved in perioperative medicine.

METHODS

The literature search was performed on PubMed and the Summaries of Product Characteristics of 6 pharmacologic agents of interest: fibrinogen concentrate, vonicog alfa, susoctocog alfa, idarucizumab, andexanet alfa, and argatroban.

RESULTS AND DISCUSSION

This review highlights renewed interest in fibrinogen concentrate, an old prohemostatic drug, in correcting hypofibrinogenemia which is a leading pathomechanism of perioperative bleeding. This review describes clinically relevant aspects for brand new recombinant prohemostatic drugs for their use in critical clinical situations: vonicog alfa for the prevention and correction of bleeding in von Willebrand syndrome, and susoctocog alfa in acquired hemophilia A. Clinical experience and increasing evidence broadened the field of applications of the old antithrombotic drug argatroban to heparin resistance. New antidotes against new antithrombotic agents revolutionized the safety of chronic antithrombotic therapy in the emergency situations of acute and trauma surgery. Information on dosing and handling of new hemostatic drugs is summarized.

CONCLUSION

New and potent hemostatic agents exist for perioperative use and may enrich the armamentarium of anesthesiologists. Implementation into clinical practice requires their availability and user knowledge. Sustainability of these new drugs depends on post-licensing research, cost-effectiveness, and clinical experience.

Next Generation Medical Management of Postpartum Hemorrhage

BACKGROUND

Postpartum hemorrhage remains a significant contributor to morbidity and mortality of women of childbearing age worldwide. Trends in both incidence and severity of postpartum hemorrhage are increasing which makes it imperative to identify drugs that could target prevention and/or treatment of these postpartum hemorrhages for women living in high, middle and low-income countries.

METHODS

We have reviewed current advances in the medical management of postpartum hemorrhage focusing on non-uterotonic therapy. We specifically describe the use and mechanism of action of tranexamic acid (TXA) and fibrinogen concentrate. Furthermore, we address the existing data for using these medications in postpartum hemorrhage, highlighting both strengths and limitations.

RESULTS

This review describes a new generation of medications that are promising for the prevention and/or treatment of postpartum hemorrhage. For patients at risk for significant hemorrhage, TXA has been shown to reduce intraoperative blood loss and can be given as a prophylactic agent. For the treatment of postpartum hemorrhage, early use of TXA has the potential to reduce mortality. In addition, some data exists supporting the use of fibrinogen concentrate, though more studies are required to help formulate guidelines for its use.

CONCLUSION

A promising new approach for the management of severe postpartum hemorrhage is using medications that alter coagulation. More data are needed to describe ideal patient populations, dosing, the time of administration, and infusion rate.

Utility of prothrombin complex concentrate as first-line treatment modality of coagulopathy in patients undergoing liver transplantation: A propensity score-matched study

BACKGROUND

Transfusion management during liver transplantation (LT) is aimed at reducing blood loss and allogeneic transfusion requirements. Although prothrombin complex concentrate (PCC) has been used satisfactorily in various bleeding disorders, studies on its safety, and efficacy during LT are limited.

METHODS

A retrospective chart review of adult patients who underwent living donor LT at a single institute between October 2016 and January 2018 was carried out. The safety and efficacy of PCC in reducing transfusion requirements intraoperatively in patients who received PCC were compared with patients who did not receive PCC. A propensity score-matching technique was used, at a 1:1 ratio, to remove selection bias.

RESULTS

After completing the 1:1 propensity score-matched analysis, 60 pairs of patients were identified. The use of PCC was associated with significantly decreased red blood cell transfusion requirements (6.2 ± 4.1 vs 8.23 ± 5.18, P < 0.001) and fresh frozen plasma transfusion requirements (2.6 ± 2 vs 6.18 ± 4.1, P < 0.001). The number of patients developing postoperative hemorrhagic complications was higher in the non-PCC group.

CONCLUSIONS

During LT, the use of PCC led to decreased transfusion requirements. No thromboembolic complications related to PCC were noted in this series.

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.

Maintaining Plasma Fibrinogen Levels and Fibrinogen Replacement Therapies for Treatment of Intracranial Hemorrhage

BACKGROUND

Intracranial hemorrhage is characterized by the blood vessel rupture and subsequent hematoma expansion. It is the least treatable stroke subtype, resulting in higher morbidity and mortality per incidence than ischemic stroke. Recent studies have observed lower than normal levels of plasma fibrinogen in patients of intracerebral hemorrhage. Furthermore, in other cases of severe hemorrhage, plasma fibrinogen levels have been identified as an indicator of prognosis. Current clinical management of cerebral hemorrhage includes adjunctive therapies and possible surgical evacuation. However, a possible therapeutic target for intracranial hemorrhage is fibrinogen. During intracranial hemorrhage with hematoma expansion, fibrinogen levels are rapidly depleted and thus are in need of replacement. Maintaining high levels of fibrinogen can promote rapid clotting and reduction of hematoma expansion.

OBJECTIVES

Within this review, we examine the role of fibrinogen in intracranial hemorrhage and evaluate the use of fibrinogen replacement therapies for maintaining normal levels of this key hemostatic protein. The pros and cons are discussed and an opinion of the most appropriate fibrinogen replacement therapy for intracranial hemorrhage is made.

CONCLUSION

It is concluded that fibrinogen concentrate seems to be the most suitable therapy for elevating plasma fibrinogen for the treatment of intracranial hemorrhage with hematoma expansion.

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.

Congenital afibrinogenemia: from etiopathogenesis to challenging clinical management

INTRODUCTION

Congenital afibrinogenemia belongs to the group of autosomal recessive bleeding disorders and represents the absolute deficiency of fibrinogen detected by an antigenic test. This can lead to severe clinical manifestations of the disorder. Therefore, it is very important to take afibrinogenemia into account in the process of the differential diagnostics of the patients.

AREAS COVERED

The authors provide a summary of currently available literature about afibrinogenemia. They collected the information from the scientific journals dedicated to thrombosis and hemostasis and searched world-wide databases. Expert commentary: The most frequent clinical manifestation of this disorder is mucosal bleeding, but musculoskeletal bleeding pattern, gynecologic and obstetric issues, spontaneous bleeding, episodes provoked by minor injury or any other intervention, and even paradoxical thromboembolic events have been published. Afibrinogenemia is the consequence of mutations of the homozygous or compound heterozygous type in gene FGA, FGB or FGG encoding fibrinogen. Pregnant women with a family history, or with a history of consanguinity ought to be properly counselled. However, primary prophylaxis of bleeding events is not suggested. The article deals with actual information about afibrinogenemia contributing to its early diagnosis and effective treatment, which in many cases requires multidisciplinary approach.

Effect of coagulation factor concentrate administration on ROTEM® parameters in major trauma

BACKGROUND

Purified coagulation factor concentrates, such as fibrinogen concentrate (FC) and prothrombin complex concentrate (PCC) are increasingly used as haemostatic therapy for trauma-induced coagulopathy (TIC). The impact of FC and PCC administration on ROTEM parameters among patients with TIC has not been adequately investigated.

METHODS

In this retrospective observational study, changes to ROTEM parameters, induced by three different therapeutic interventions, were investigated: patients receiving FC only (FC-group); patients treated with FC and PCC (FC + PCC-group) and patients treated with PCC only (PCC-group).

RESULTS

The study population comprised 96 patients who were predominately male (69 [71.9 %]), median age was 45.0 (26.3-60.0) years, and the median injury severity score was 34.0 (25.0-44.5). Administration of FC resulted in a significant reduction of the clotting time (CT) in both the EXTEM and FIBTEM assays but had no effect on INTEM CT. Clot amplitude (CA) increased significantly in the FIBTEM assay but remained unchanged in the EXTEM and INTEM assays. The combined administration of FC and PCC increased FIBTEM maximum clot firmness (MCF) and normalized EXTEM CT but did not change either INTEM or FIBTEM CT. Following PCC therapy, EXTEM and FIBTEM CT normalized; CA at 10 min after CT measurements decreased significantly in EXTEM, INTEM and FIBTEM.

CONCLUSIONS

Administration of FC alone or in combination with PCC resulted in a significant improvement of fibrin polymerisation as measured by an increase in FIBTEM MCF. CT is dependent not only on thrombin generation but also on the availability of substrate (fibrinogen). Accelerated fibrin polymerisation rate results in earlier clot formation and consequently shorter CT. PCC administration normalised EXTEM CT below the upper threshold of 80 s. This study was performed at the AUVA Trauma Centre Salzburg, Salzburg, Austria.

Impact of the intraoperative use of fibrinogen concentrate for hypofibrinogenemia during thoracic aortic surgery

Thoracic aortic surgery often causes massive bleeding due to coagulopathy. Hypofibrinogenemia is one of the major causative factors, but the utility of the intraoperative administration of fibrinogen concentrate has not yet been proven. The aim of this study was to estimate incidence of hypofibrinogenemia and to evaluate efficacy of using fibrinogen concentrate intraoperatively. The perioperative serum fibrinogen levels (SFL) had routinely been measured in consecutive 216 thoracic aortic surgeries performed from 2010 to 2012. Fibrinogen concentrate was principally used for hypofibrinogenemia (< 150 mg/dl of SFL) at cardiopulmonary bypass (CPB) termination. The patients who received fibrinogen concentrate (FIB group) were compared with the patients who did not received (non Fib group). There were 147 patients (68%) in FIB group at a dose of 5.5±3.5 g. The SFL were dramatically decreased with values of 164±71 mg/dl at CPB termination, compared to the preoperative SFL of 352±131 mg/dl. In the FIB group, the intraoperative and postoperative SFLs were 139±53 and 262±75 (mg/dl), respectively. Thus the SFL was recovered quickly by the administration. 110 cases (51%) showed hypofibrinogenemia at the termination of CPB. The predictors of hypofibrinogenemia were preoperative SFL < 250 mg/dl, emergency surgery and thracoabdominal aortic surgery. Hypofibrinogenemia frequently was observed at the termination of CPB during thoracic aortic surgery. Administering intraoperative fibrinogen concentrate appears to be a useful option to treat coagulopathy.

Fibrinogen depletion after plasma-dilution: impairment of proteolytic resistance and reversal via clotting factor concentrates

In trauma patients, resuscitation treatment of intravascular volume may cause haemodilution including blood cell- and plasma-dilution. After plasma-dilution, fibrinogen is the first factor that decreases to critically low concentrations. Fibrin formed in lowered levels is susceptible to fibrinolysis, a natural forerunner for bleeding. To assess whether a fibrinogen concentrate or a factor XIII (FXIII) concentrate can reverse the impairment of fibrin properties after plasma dilution, different laboratory methods were used to determine thrombin generation and fibrin quantity/quality in a normal plasma sample diluted in vitro. Coagulation and clot lysis by plasmin were triggered with tissue factor and rt-PA, respectively.We found that while the endogenous thrombin potential (ETP) was unaffected after plasma-dilution due to postponement of thrombin decay, levels of fibrinogen and hence fibrin were decreased in dilution degree-dependency. The imbalance between influence of the dilution on thrombin activity and fibrin formation brought unexpected outcomes of fibrin properties: the formed clots favoured the degradation by plasminbut the fibrin networks remained tighter/less permeable. This proteolytic tendency was partly overturned by the fibrinogen concentrate added (total fibrinogen ≥ 2 g/l), and much more affected if used in combination with tranexamic acid (a fibrinolysis inhibitor) at small doses. No reversal effect resulted from the FXIII concentrate added. We conclude that plasma-dilution did reduce the proteolytic resistance of formed clots. The fibrinogen concentrate, better together with small doses of tranexamic acid, may reverse the impairment of fibrin property.The FXIII concentrate is not effective in this regard in our in vitro model using platelet-poor plasma.

Treatment of congenital fibrinogen deficiency: overview and recent findings

Afibrinogenemia is a rare bleeding disorder with an estimated prevalence of 1:1,000,000. It is an autosomal recessive disease resulting from mutations in any of the 3 genes that encode the 3 polypeptide chains of fibrinogen and are located on the long arm of chromosome 4. Spontaneous bleeding, bleeding after minor trauma and excessive bleeding during interventional procedures are the principal manifestations. We review the management of afibrinogenemia. Replacement therapy is the mainstay of treatment of bleeding episodes in these patients and plasma-derived fibrinogen concentrate is the agent of choice. Cryoprecipitate and fresh frozen plasma are alternative treatments that should be used only when fibrinogen concentrate is not available. Secondary prophylactic treatment may be considered after life-threatening bleeding whereas primary prophylactic treatment is not currently recommended. We also discuss alternative treatment options and the management of surgery, pregnancy and thrombosis in these patients. The development of new tests to identify higher risk patients and of safer replacement therapy will improve the management of afibrinogenemia in the future.