How I use fibrinogen replacement therapy in acquired bleeding

Unresponsiveness of Activated Partial Thromboplastin Time to Bivalirudin in Adults Receiving Extracorporeal Membrane Oxygenation

Activated partial thromboplastin time (aPTT) is the standard for monitoring bivalirudin but demonstrates a nonlinear response at higher drug concentrations. The objective of this study was to assess the relationship between bivalirudin dose and aPTT in patients receiving extracorporeal membrane oxygenation (ECMO) to determine a threshold where aPTT unresponsiveness occurs. Two hundred fourteen adults receiving bivalirudin during ECMO between 2018 and 2022 were included. Piecewise regression in a linear mixed effects model was used to determine a bivalirudin dose threshold of 0.21 mg/kg/hr for aPTT unresponsiveness. For doses of less than 0.21 mg/kg/hr (n = 135), every 0.1 mg/kg/hr dose increase led to an aPTT increase of 11.53 (95% confidence interval [CI] = 9.85-13.20) seconds compared to only a 3.81 (95% CI = 1.55-6.06) seconds increase when dose was greater than or equal to 0.21 mg/kg/hr (n = 79) ( pinteraction < 0.001). In multivariable logistic regression, venovenous configuration (odds ratio [OR] = 2.83, 95% CI = 1.38-5.77) and higher fibrinogen concentration (OR = 1.22, 95% CI = 1.05-1.42) were associated with greater odds of unresponsiveness, whereas older age (OR = 0.79, 95% CI = 0.63-0.98), kidney dysfunction (OR = 0.48, 95% CI = 0.25-0.92), and a higher baseline aPTT (OR = 0.89, 95% CI = 0.82-0.97) were associated with lower odds. Alternative methods are necessary to ascertain bivalirudin's hemostatic impact when doses exceed 0.21 mg/kg/hr during ECMO.

Recent Advances in Topical Hemostatic Materials

Untimely or improper treatment of traumatic bleeding may cause secondary injuries and even death. The traditional hemostatic modes can no longer meet requirements of coping with complicated bleeding emergencies. With scientific and technological advancements, a variety of topical hemostatic materials have been investigated involving inorganic, biological, polysaccharide, and carbon-based hemostatic materials. These materials have their respective merits and defects. In this work, the application and mechanism of the major hemostatic materials, especially some hemostatic nanomaterials with excellent adhesion, good biocompatibility, low toxicity, and high adsorption capacity, are summarized. In the future, it is the prospect to develop multifunctional hemostatic materials with hemostasis and antibacterial and anti-inflammatory properties for promoting wound healing.

Early Goal-Directed Hemostatic Therapy for Severe Acute Bleeding Management in the Intensive Care Unit: A Narrative Review

This is a narrative review of the published evidence for bleeding management in critically ill patients in different clinical settings in the intensive care unit (ICU). We aimed to describe "The Ten Steps" approach to early goal-directed hemostatic therapy (EGDHT) using point-of-care testing (POCT), coagulation factor concentrates, and hemostatic drugs, according to the individual needs of each patient. We searched National Library of Medicine, MEDLINE for publications relevant to management of critical ill bleeding patients in different settings in the ICU. Bibliographies of included articles were also searched to identify additional relevant studies. English-language systematic reviews, meta-analyses, randomized trials, observational studies, and case reports were reviewed. Data related to study methodology, patient population, bleeding management strategy, and clinical outcomes were qualitatively evaluated. According to systematic reviews and meta-analyses, EGDHT guided by viscoelastic testing (VET) has been associated with a reduction in transfusion utilization, improved morbidity and outcome in patients with active bleeding. Furthermore, literature data showed an increased risk of severe adverse events and poor clinical outcomes with inappropriate prophylactic uses of blood components to correct altered conventional coagulation tests (CCTs). Finally, prospective, randomized, controlled trials point to the role of goal-directed fibrinogen substitution to reduce bleeding and the amount of red blood cell (RBC) transfusion with the potential to decrease mortality. In conclusion, severe acute bleeding management in the ICU is still a major challenge for intensive care physicians. The organized and sequential approach to the bleeding patient, guided by POCT allows for rapid and effective bleeding control, through the rational use of blood components and hemostatic drugs, since VET can identify specific coagulation disorders in real time, guiding hemostatic therapy with coagulation factor concentrates and hemostatic drugs with individual goals.

Prospective, Randomized Study of Fibrinogen Concentrate Versus Cryoprecipitate for Correcting Hypofibrinogenemia in Cardiac Surgery Patients

OBJECTIVE

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with hypofibrinogenemia and severe bleeding requiring transfusion. Guidelines recommend cryoprecipitate or fibrinogen concentrate (FC) for the treatment of acquired hypofibrinogenemia. This study compared cryoprecipitate and FC for the correction of acquired hypofibrinogenemia and the associated costs.

DESIGN

A single-center, prospective, randomized study evaluating patients with hypofibrinogenemia after cardiac surgery. The primary endpoint was direct treatment cost. Secondary endpoints included the change in fibrinogen level after FC and/or cryoprecipitate dosing.

SETTING

A single-center study in Astana, Kazakhstan.

PARTICIPANTS

Participants who underwent CPB from 2021 to 2022 and developed clinically significant bleeding and hypofibrinogenemia.

INTERVENTIONS

Patients were randomized to receive cryoprecipitate or FC.

MEASUREMENTS AND MAIN RESULTS

Eighty-eight adult patients with acquired hypofibrinogenemia (<2.0 g/L) after CPB were randomized to receive cryoprecipitate (N = 40) or FC (N = 48), with similar demographics between groups. Overall, mean ± SD 9.33 ± 0.94 units (range, 8-10) cryoprecipitate or 1.40 ± 0.49 g (1-2) FC was administered to the 2 groups. From before administration to 24 hours after, mean plasma fibrinogen increased by a mean ± SD of 125 ± 65 and 96 ± 65 mg/dL in the cryoprecipitate and FC groups, respectively. At 48 hours after administration, there was no significant difference in fibrinogen levels between groups. The mean direct cost of treatment with FC was significantly lower than with cryoprecipitate (p < 0.0001): $1,505.06 ± $152.40 and $631.75 ± $223.67 per patient for cryoprecipitate and FC, respectively.

CONCLUSION

Analysis of plasma fibrinogen concentration showed that cryoprecipitate and FC had comparable effectiveness. However, FC is advantageous over cryoprecipitate due to its ease of handling, lower cost, and high purity.

Assessment of fibrinogen albumin ratio in patients with pregnancy-related cerebral venous thrombosis

INTRODUCTION AND OBJECTIVE

Cerebral venous thrombosis (CVT) is a cerebrovascular disease observed more commonly in women of childbearing age. There is currently no biomarker used to predict the risk of CVT during the follow-up of pregnant/postpartum patients. In this context, the objective of this study is to investigate the importance of fibrinogen and albumin levels and fibrinogen-to-albumin ratio (FAR) values, which predispose to thromboembolism, in pregnant/postpartum patients.

MATERIAL AND METHOD

The study sample consisted of 19 pregnant/postpartum patients with a diagnosis of CVT, 20 pregnant/postpartum patients without CVT. Albumin and fibrinogen levels and FAR values were compared between these two groups.

RESULTS

Fibrinogen level was significantly higher in pregnant/postpartum CVT patients compared to pregnant/postpartum patients without CVT (p = 0.010). On the other hand, albumin level was significantly lower in pregnant/postpartum CVT patients compared to the other group (p = 0.010). Lastly, FAR level was significantly higher in pregnant/postpartum CVT patients compared to the other group (p = 0.011). There was no correlation between FAR values and modified Rankin score.

CONCLUSION

The study findings indicated that high fibrinogen and low albumin levels and high FAR values are associated with an increased risk of CVT in pregnant/postpartum patients.

Design and Development of a Clot Burst Pressure Device to Investigate Resuscitation Strategies

INTRODUCTION

A reduction in clot strength is a hallmark feature of trauma-induced coagulopathy. A better understanding of clot integrity can optimize resuscitation strategies. We designed a device to gauge clot strength by pressurizing fluids over a formed clot and measuring the pressure needed to dislodge the clot. We hypothesized that this device could distinguish between clots formed in hypocoagulable and hypercoagulable states by observing differences in the clot burst pressure.

METHODS

Whole blood from healthy volunteers was collected into sodium citrate tubes and was treated with heparin or fibrinogen to generate clots in a hypocoagulable or hypercoagulable state, respectively. Small bore holes were drilled into polystyrene plates, and recalcified blood was pipetted into the holes. Plates were incubated at 37°C for 30 min to form clots. A pressure cap with an inlet for fluid from a syringe pump and an outlet leading to a measurement column was secured in the wells with a watertight seal.

RESULTS

Clot burst pressure was normalized to individual baseline values to account for inherent differences in clot strength. The 1.0 g/L and 2.0 g/L fibrinogen groups were 1.65 ± 0.07 (P = 0.0078) and 2.26 ± 0.16 (P = 0.0078) times as strong as baseline, respectively. The 0.10, 0.15, or 0.20 USP units/mL groups were 0.388 ± 0.07 (P = 0.125), 0.31 ± 0.07 (P = 0.125), 0.21 ± 0.07 (P = 0.125) times as strong as baseline, respectively. Data were analyzed using Wilcoxon matched pairs signed rank testing.

CONCLUSIONS

This device tests clot strength using burst pressure, an easily interpreted clinical parameter not measured in existing devices. Future work can test blood from trauma patients to better understand trauma pathophysiology.

Differences in coagulation-relevant parameters: Comparing cryoprecipitate and a human fibrinogen concentrate

BACKGROUND

Variable fibrinogen content within cryoprecipitate makes accurate dosing challenging in patients with coagulopathic bleeding, in addition to pathogen transmission risks associated with its administration. Purified and standardized human fibrinogen concentrates (HFCs) represent reliable alternatives. Full cryoprecipitate characterization is required to inform selection of an appropriate fibrinogen source for supplementation therapy.

METHODS

Extended biochemical comparison of pooled cryoprecipitate and HFC (Fibryga, Octapharma) was performed using commercially available assays to determine levels of variability in cryoprecipitate and HFC. In addition to standard procoagulant factors, measurements included activities of platelet-derived microparticles (PMPs) and plasminogen, and levels of fibrin degradation products.

RESULTS

Cryoprecipitate contains lower fibrinogen levels than HFC (4.83 vs.19.73 g/L; p<0.001), translating to approximately half the amount of fibrinogen per standard cryoprecipitate dose (two pools, pre-pooled from five donations each) vs. HFC (2.14 vs. 3.95 g; p<0.001). Factor XIII (FXIII) levels were also lower in cryoprecipitate vs. HFC (192.17 vs. 328.33 IU/dL; p = 0.002). Levels of procoagulants in cryoprecipitate, such as von Willebrand Factor (VWF) and factor VIII (FVIII), were highly variable, as was PMP activity. A standard cryoprecipitate dose contains significantly higher levels of measured plasminogen and D-dimer fragments than a standard HFC dose.

CONCLUSION

The tested HFC is a more reliable fibrinogen and FXIII source for accurate dosing compared with cryoprecipitate. Cryoprecipitate appears considerably less predictable for bleeding management due to wide variation in pro- and anticoagulation factors, the presence of PMPs, and the potential to elevate VWF and FVIII to prothrombotic levels.

Heparin-Immobilized Polyethersulfone for Hemocompatibility Enhancement of Dialysis Membrane: In Situ Synchrotron Imaging, Experimental, and Ex Vivo Studies

The goal of the current study is to enhance the hemocompatibility of polyethersulfone (PES) membranes using heparin immobilization. Heparin was immobilized covalently and via electrostatic interaction with the positively charged PES surface (pseudo-zwitterionic (pZW) complex) to investigate the influence of each method on the membrane hemocompatibility. In situ synchrotron radiation micro-computed tomography (SR-µCT) imaging, available at the Canadian Light Source (CLS), was used to critically assess the fibrinogen adsorption to the newly synthesized membranes qualitatively and quantitatively using an innovative synchrotron-based X-ray tomography technique. The surface roughness of the synthesized membranes was tested using atomic force microscopy (AFM) analysis. The membrane hemocompatibility was examined through the ex vivo clinical interaction of the membranes with patients' blood to investigate the released inflammatory biomarkers (C5a, IL-1α, IL-1β, IL-6, vWF, and C5b-9). The presence and quantitative analysis of a stable hydration layer were assessed with DSC analysis. Surface modification resulted in reduced surface roughness of the heparin-PES membrane. Both types of heparin immobilization on the PES membrane surface resulted in a decrease in the absolute membrane surface charge from -60 mV (unmodified PES) to -13 mV for the pZW complex and -9.16 mV for the covalently attached heparin, respectively. The loss of human serum fibrinogen (FB) was investigated using UV analysis. The PES membrane modified with the heparin pseudo-ZW complex showed increased FB retention (90.5%), while the unmodified PES membrane and the heparin covalently attached PES membrane exhibited approximately the same level of FB retention (81.3% and 79.8%, respectively). A DSC analysis revealed an improvement in the content of the hydration layer (32% of non-freezable water) for the heparin-coated membranes compared to the unmodified PES membrane (2.84%). An SR-µCT analysis showed that the method of heparin immobilization significantly affects FB adsorption distribution across the membrane thickness. A quantitative analysis using SR-µCT showed that when heparin is attached covalently, FB tends to be deposited inside the membrane pores at the top (layer index 0-40) membrane regions, although its content peak distribution shifted to the membrane surface, whereas the unmodified PES membrane holds 90% of FB in the middle (layer index 40-60) of the membrane. The ex vivo hemocompatibility study indicates an improvement in reducing the von Willebrand factor (vWF) for the heparin pseudo-ZW PES membrane compared to the covalently attached heparin and the untreated PES.

Anesthesia Considerations for Placenta Accreta Spectrum

Anesthesiologists are critical members of the multidisciplinary team managing patients with suspected placenta accreta spectrum (PAS). Preoperatively, anesthesiologists provide predelivery consultation for patients with suspected PAS where anesthetic modality and invasive monitor placement is discussed. Additionally, anesthesiologists carefully assess patient and surgical risk factors to choose an anesthetic plan and to prepare for massive intraoperative hemorrhage. Postoperatively, the obstetric anesthesiologist hold unique skills to assist with postoperative pain management for cesarean hysterectomy. We review the unique aspects of peripartum care for patients with PAS who undergo cesarean hysterectomy and explain why these responsibilities are critical for achieving successful outcomes for patients with PAS. KEY POINTS: · Anesthesiologists are critical members of the multidisciplinary team planning for patients with suspected placenta accreta spectrum.. · Intraoperative preparation for massive hemorrhage is a key component of anesthetic care for patients with PAS.. · Obstetric anesthesiologists have a unique skill set to manage postpartum pain and postoperative disposition for patients with PAS who undergo cesarean hysterectomy..

Etiology and management of hypofibrinogenemia in trauma

PURPOSE OF REVIEW

Fibrin polymerization is essential for stable clot formation in trauma, and hypofibrinogenemia reduces hemostasis in trauma. This review considers fibrinogen biology, the changes that fibrinogen undergoes after major trauma, and current evidence for lab testing and treatment.

RECENT FINDINGS

Fibrinogen is a polypeptide that is converted to fibrin by the action of thrombin. During trauma, fibrinogen levels are consumed and reduce within the first few hours because of consumption, dilution, and fibrinolysis. Fibrinogen levels usually rebound within 48 hours of injury and can contribute to thrombotic events. The Clauss fibrinogen assay is the gold standard test for fibrinogen levels, although viscoelastic hemostatic assays are often used when a lab delay is anticipated. An evidence-based threshold for fibrinogen replacement is not well established in the literature, but expert opinion recommends maintaining a level above 150 mg/dl.

SUMMARY

Hypofibrinogenemia is an important cause of nonanatomic bleeding in trauma. Despite multiple pathologic causes, the cornerstone of treatment remains fibrinogen replacement with cryoprecipitate or fibrinogen concentrates.

Blood Product Replacement for Postpartum Hemorrhage

Consideration for blood products replacement in postpartum hemorrhage should be given when blood loss exceeds 1.5 L or when an estimated 25% of blood has been lost. In cases of massive hemorrhage, standardized transfusion protocols have been shown to improve maternal morbidity and mortality. Most protocols recommend a balanced transfusion involving a 1:1:1 ratio of packed red blood cells, platelets, and fresh frozen plasma. Alternatives such as cryoprecipitate, fibrinogen concentrate, and prothrombin complex concentrates can be used in select clinical situations. Although transfusion of blood products can be lifesaving, it does have associated risks.

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.

The potential impact of coagulation factor XIII in trauma-induced coagulopathy - a retrospective case series analysis

BACKGROUND

The role of factor XIII (FXIII) in trauma-induced coagulopathy (TIC) is not fully understood.

METHODS

We evaluated FXIII supplementation in severely injured patients with persistent bleeding. This was a retrospective case series analysis.

RESULTS

Twenty-four patients received FXIII concentrate within 24 h of admission for bleeding that continued after transfusion of > 6 U red blood cells (RBCs); control patients (n = 27) did not receive FXIII concentrate. Both study groups were similar regarding injury severity score and global coagulation tests, but FXIII activity levels were significantly higher and lactate levels significantly lower in the control group, respectively. The differences in FXIII activity between the groups could be attributed to a more severe trauma-induced coagulopathy in FXIII-deficient patients, as demonstrated by lower fibrinogen and higher lactate levels. The median dose of FXIII concentrate within 24 h of admission was 2500 IU (IQR: 1250-4375). Median 24-h transfusion of RBCs (primary study endpoint) was significantly higher in the FXIII group versus controls (10.0 U, IQR 5-14 U vs. 2, IQR 0-6 U; p < 0.01). Subsequently, while patients were in the intensive care unit, there was no statistically significant difference regarding RBC transfusion anymore and the overall clinical outcomes were similar in both patient groups.

CONCLUSIONS

The substitution of FXIII in patients who were more seriously compromised due to higher lactate levels and who presented with initially more severe bleedings than patients in the control group, resulted in a comparable transfusion necessity after 24 h. Thus, we guess that the substitution of FXIII in severely injured patients with ongoing bleeding might have an impact on their clinical outcome.

Advances in the development and optimization strategies of the hemostatic biomaterials

Most injuries are accompanied by acute bleeding. Hemostasis is necessary to relieve pain and reduce mortality in these accidents. In recent years, the traditional hemostatic materials, including inorganic, protein-based, polysaccharide-based and synthetic materials have been widely used in the clinic. The most prominent of these are biodegradable collagen sponges (Helistat^®, United States), gelatin sponges (Ethicon^®, SURGIFOAM^®, United States), chitosan (AllaQuixTM, ChitoSAMTM, United States), cellulose (Tabotamp^®, SURGICEL^®, United States), and the newly investigated extracellular matrix gels, etc. Although these materials have excellent hemostatic properties, they also have their advantages and disadvantages. In this review, the performance characteristics, hemostatic effects, applications and hemostatic mechanisms of various biomaterials mentioned above are presented, followed by several strategies to improve hemostasis, including modification of single materials, blending of multiple materials, design of self-assembled peptides and their hybrid materials. Finally, the exploration of more novel hemostatic biomaterials and relative coagulation mechanisms will be essential for future research on hemostatic methods.

Major haemorrhage: past, present and future

Major haemorrhage is a leading cause of morbidity and mortality worldwide. Successful treatment requires early recognition, planned responses, readily available resources (such as blood products) and rapid access to surgery or interventional radiology. Major haemorrhage is often accompanied by volume loss, haemodilution, acidaemia, hypothermia and coagulopathy (factor consumption and fibrinolysis). Management of major haemorrhage over the past decade has evolved to now deliver a 'package' of haemostatic resuscitation including: surgical or radiological control of bleeding; regular monitoring of haemostasis; advanced critical care support; and avoidance of the lethal triad of hypothermia, acidaemia and coagulopathy. Recent trial data advocate for a more personalised approach depending on the clinical scenario. Fresh frozen plasma should be given as early as possible in major trauma in a 1:1 ratio with red blood cells until the results of coagulation tests are available. Tranexamic acid is a cheap, life-saving drug and is advocated in major trauma, postpartum haemorrhage and surgery, but not in patients with gastrointestinal bleeding. Fibrinogen levels should be maintained > 2 g.l^-1 in postpartum haemorrhage and > 1.5 g.l^-1 in other haemorrhage. Improving outcomes after major traumatic haemorrhage is now driving research to include extending blood-product resuscitation into prehospital care.

Intravenous Hemostats: Foundation, Targeting, and Controlled-Release

Uncontrollable blood loss is the greatest cause of mortality in prehospital patients and the main source of disability and death in hospital care. Compared with external hemostats, intravenous hemostats are more appropriate for preventing and treating uncontrolled bleeding in vivo and large bleeding on the body surface. This Review initially establishes intravenous hemostats' response basis, including the coagulation mechanism, fibrinolytic pathway, and protein corona. Second, the study of advancement of intravenous hemostat targeting was expanded from two perspectives, cellular hemostatic agents and synthetic hemostatic agents. Meanwhile, after discussing the progress of controlled-release intravenous hemostats with platelets as the stimuli, this Review offers insight into the possibility of controlled-release intravenous hemostats with microenvironment as the stimuli, combining the studies of controlled-release targeted thrombolysis.

Does Intraoperative Fibrinogen Affect Blood Loss or Transfusion Practice After Aortic Arch Surgery: A Prematurely Ended Randomized Trial

Cardiovascular surgery is often complicated by significant bleeding due to perioperative coagulopathy. The effectiveness of treatment with fibrinogen concentrate to reduce the perioperative blood transfusion rate after thoracic aortic replacement surgery in prior studies has shown conflicting results. Therefore, we conducted a double-blind randomized controlled trial to investigate if a single dose of intraoperative fibrinogen administration reduced blood loss and allogeneic transfusion rate after elective surgery for thoracic arch aneurysm with deep hypothermic circulatory arrest. Twenty patients were randomized to fibrinogen concentrate (N = 10) or placebo (N = 10). The recruitment of study patients was prematurely ended due to a low inclusion rate. Perioperative transfusion, 5-minute bleeding mass after study medication and postoperative blood loss were not different between the groups with fibrinogen concentrate or placebo. Due to small volumes of postoperative blood loss and premature study termination, a beneficial effect of fibrinogen concentrate on the number of blood transfusions could not be established. However, treatment with fibrinogen efficiently restored fibrinogen levels and clot strength to preoperative values with a more effective preserved postoperative thrombin generation capacity. This result might serve as a pilot for further multicenter studies to assess the prospective significance of automated and standardized thrombin generation as a routine assay for monitoring perioperative coagulopathy and its impact on short- and long-term operative results.

The Role of Major Inflammatory Biomarkers in the Pathogenesis of Atrial Fibrillation

Many studies have reported a relationship between inflammation and atrial fibrillation (AF). According to the literature, inflammation is the key component in pathophysiological processes during the development of AF; the amplification of inflammatory pathways triggers AF, and, at the same time, AF increases the inflammatory state. The plasma levels of several inflammatory biomarkers are elevated in patients with AF; therefore, inflammation might contribute to both the maintenance and occurrence of AF and its thromboembolic complications. Numerous inflammatory markers have been linked to AF, including CD40 ligand, fibrinogen, matrix metalloproteinase (MMP)-9, monocyte chemoattractant protein-1, myeloperoxidase, plasminogen activator inhibitor-1, and serum amyloid A. There are many pathophysiological aspects of AF that are linked to these inflammatory biomarkers, including atrial structural remodeling and atrial dilatation, increased atrial myocyte expression, fluctuations in calcium cycling, cardiac remodeling promotion, increased cardiac myocyte proliferation and terminal differentiation, production of several MMPs, the pathogenesis of atherosclerosis and cardiomyocyte apoptosis, an increased degree of fibrosis in atrial myocardium, and the progression and development of atherogenesis and atherothrombosis. The present review article aims to provide an updated overview and focus on the basic role of different biomarkers of inflammation in the pathophysiological aspects of the pathogenesis of AF.

Analysis of the clinical characteristics of tigecycline-induced hypofibrinogenemia

Knowledge regarding the association between hypofibrinogenemia and tigecycline is based mainly on case reports. However, the clinical features of tigecycline-induced hypofibrinogenemia are unclear. We collected 20 patients (16 males and 4 females) with tigecycline-induced hypofibrinogenemia by searching the Chinese and English databases from June 2005 to May 2021, with a median age of 63.5 years (range 39∼90 years). Hypofibrinogenemia developed at a median of 9 days (range 2∼35 days). Most patients had no typical clinical manifestations, and only a few patients had bleeding and ecchymosis. Fibrinogen levels gradually decreased from 3.98 ± 2.05 g/L to 0.87 ± 0.45 g/L (P = 0.000), and the activated partial thromboplastin time (APTT) increased from 38.26 ± 8.80 s to 83.43 ± 47.23 s (P = 0.002). Fibrinogen levels in all patients recovered to the normal range within a median of 4 days (range 1∼12 days) after tigecycline cessation. Our results suggest that fibrinogen levels should be closely monitored in patients treated with tigecycline, specifically patients who may have renal insufficiency or patients with long-term use.

Weight-adjusted dosing of fibrinogen concentrate and cryoprecipitate in the treatment of hypofibrinogenaemic bleeding adult cardiac surgical patients: a post hoc analysis of the Fibrinogen Replenishment in cardiac surgery randomised controlled trial

Background

Hypofibrinogenaemia is associated with excessive bleeding after cardiac surgery. Our aim was to compare the efficacy and safety of weight-adjusted vs empiric dosing of fibrinogen replacement in cardiac surgery.

Methods

In the Fibrinogen Replenishment in Cardiac Surgery (FIBRES) RCT, patients (n=735) received fibrinogen concentrate (4 g) or cryoprecipitate (10 units). In this post-hoc analysis, patients were grouped into quartiles based on increasing weight-adjusted dosing. Generalised estimating equations were used to account for hospital site, age, sex, surgical complexity, urgency, and critical preoperative status. The primary outcome was the number of units of red blood cells transfused within 24 h of cardiopulmonary bypass. Secondary outcomes included allogeneic blood components within 24 h, tamponade or major bleeding, and thromboembolic complications, ischaemic complications, or both within 28 days of cardiopulmonary bypass.

Results

The median weight-adjusted doses were 52 mg kg-1 of fibrinogen concentrate (inter-quartile range [IQR], 45-61; n=372) and 1.30 units per 10 kg of cryoprecipitate (IQR, 1.11-1.54; n=363). When patients were divided into quartiles of lowest to highest weight-adjusted dosing, no differences were seen in the primary outcome of red blood cell units transfused within 24 h of cardiopulmonary bypass between the lowest and highest quartiles in either the fibrinogen group (adjusted relative risk [RR]=0.90; 95% confidence interval [CI], 0.71-1.13; P=0.36) or the cryoprecipitate group (adjusted RR=1.04; 95% CI, 0.76-1.43; P=0.80). Results were similar for all secondary outcomes.

Conclusion

Outcomes for the lowest and highest weight-adjusted doses of fibrinogen replacement were comparable. Weight-adjusted dosing does not appear to offer advantages over empiric dosing in this context.

Clinical trial registration

NCT03037424.

Suppression of fibrin(ogen)-driven pathologies in disease models through controlled knockdown by lipid nanoparticle delivery of siRNA

Fibrinogen plays a pathologic role in multiple diseases. It contributes to thrombosis and modifies inflammatory and immune responses, supported by studies in mice expressing fibrinogen variants with altered function or with a germline fibrinogen deficiency. However, therapeutic strategies to safely and effectively tailor plasma fibrinogen concentration are lacking. Here, we developed a strategy to tune fibrinogen expression by administering lipid nanoparticle (LNP)-encapsulated small interfering RNA (siRNA) targeting the fibrinogen α chain (siFga). Three distinct LNP-siFga reagents reduced both hepatic Fga messenger RNA and fibrinogen levels in platelets and plasma, with plasma levels decreased to 42%, 16%, and 4% of normal within 1 week of administration. Using the most potent siFga, circulating fibrinogen was controllably decreased to 32%, 14%, and 5% of baseline with 0.5, 1.0, and 2.0 mg/kg doses, respectively. Whole blood from mice treated with siFga formed clots with significantly decreased clot strength ex vivo, but siFga treatment did not compromise hemostasis following saphenous vein puncture or tail transection. In an endotoxemia model, siFga suppressed the acute phase response and decreased plasma fibrinogen, D-dimer, and proinflammatory cytokine levels. In a sterile peritonitis model, siFga restored normal macrophage migration in plasminogen-deficient mice. Finally, treatment of mice with siFga decreased the metastatic potential of tumor cells in a manner comparable to that observed in fibrinogen-deficient mice. The results indicate that siFga causes robust and controllable depletion of fibrinogen and provides the proof-of-concept that this strategy can modulate the pleiotropic effects of fibrinogen in relevant disease models.

Real-life experiences with goal-directed prohemostatic therapy with fibrinogen concentrate, prothrombin complex concentrate, and recombinant factor VIIa: a retrospective study of 287 consecutive patients

The Danish Capital Region Blood Bank operates a 24/7 on-call service staffed with physicians specialized in hemostatic management to guide clinicians in hemostatic resuscitation, including administration of prohemostatic therapy (PHT). The outcome of patients who receive PHT as part of hemostatic resuscitation remains unanswered. The objective of this study was therefore to investigate clinical outcome of patients receiving PHT managed by the on-call service. We identified 287 patients who received PHT during 2015-16, of which 161 (59%) received fibrinogen concentrate (FC), 111 (39%) received prothrombin complex concentrate (PCC), and 15 (5%) received recombinant factor VIIa (rFVIIa) as the first product. Patients were critically ill with a 30-day mortality of 31%. Among FC recipients, cardiothoracic admission, non-trauma, and antithrombotics predicted survival. FC recipients had lower platelet count and thrombelastography clot strengths than the other PHT groups and within the group, these factors predicted mortality. The symptomatic thromboembolic event (TE) rate at 30 days was 5%. For PCC recipients, vitamin K antagonists predicted survival, while rivaroxaban predicted mortality. TE rate was 2%. We did not identify factors associated with survival in the small group of rFVIIa recipients. TE rate was 13%. In summary, trauma and coagulopathy predicted mortality in patients who received FC and our data suggest that optimization of PHT algorithms may be possible. Outcome of patients who received PCC was comparable to results reported elsewhere and its use may be safe in a setting as reported here. Recombinant FVIIa was rarely used but had the highest incidence of arterial thromboembolism.

Gastrointestinal bleeding after endoscopic mucosal resection in a case of Peutz-Jeghers syndrome with hypofibrinogenemia: A case report

BACKGROUD

Peutz-Jegers syndrome (PJS) is an autosomal dominant hereditary disorder characterized by hamartomatous polyposis of the entire gastrointestinal tract. Fibrinogen (Fbg) is synthesized by the liver, and hypofibrinogenemia is often asymptomatic and manifests with bleeding after trauma or invasive surgical procedures. Here, we present a case of a pediatric patient with PJS and hypofibrinogenemia who manifested with gastrointestinal bleeding after endoscopic mucosal resection (EMR) of small intestinal polyps.

CASE PRESENTATION

An 11-year-old boy with PJS was referred to our hospital. Since his mother was diagnosed with PJS, with black pigments being observed on his lips, mouth, and limbs, he underwent upper and lower gastrointestinal endoscopy at the age of 8 years at a previous hospital. EMR for duodenal polyp was performed, and the pathological findings were consistent with hamartoma. His Fbg level was 117 mg/dl at the time, with no post-bleeding being detected after EMR. The small intestine was not assessed at the prior facility and was left neglected for three years. At our hospital, small intestine fluoroscopy was performed and revealed a polyp in the jejunum, and abdominal computed tomography showed two polyps and intussusception. On double-balloon enteroscopy, the resected polyps were hamartoma with diameters of 20 and 30 mm. The patient's Fbg level was 107 mg/dl. The day after EMR, he had melena and black stools. He was diagnosed with post-EMR bleeding and started to stop eating, and hemostatic agents were given. His hemoglobin level dropped to 9.2 g/dl the next day. Genetic testing for congenital Fbg deficiency revealed a heterozygous pathogenic variant in fibrinogen gamma chain Exon 10. Therefore, he was diagnosed with concurrent hypofibrinogenemia and PJS.

CONCLUSION

To the best of our knowledge, this is the first reported case with concurrent PJS and hypofibrinogenemia. In patients with PJS, hypofibrinogenemia should be considered as one of the risk factors of postoperative bleeding during polypectomy, and appropriate prophylactic measures should be taken.

Polymeric Materials for Hemostatic Wound Healing

Hemorrhage is one of the greatest threats to life on the battlefield, accounting for 50% of total deaths. Nearly 86% of combat deaths occur within the first 30 min after wounding. While external wound injuries can be treated mostly using visual inspection, abdominal or internal hemorrhages are more challenging to treat with regular hemostatic dressings because of deep wounds and points of injury that cannot be located properly. The need to treat trauma wounds from limbs, abdomen, liver, stomach, colon, spleen, arterial, venous, and/or parenchymal hemorrhage accompanied by severe bleeding requires an immediate solution that the first responders can apply to reduce rapid exsanguinations from external wounds, including in military operations. This necessitates the development of a unique, easy-to-use, FDA-approved hemostatic treatment that can deliver the agent in less than 30 s and stop bleeding within the first 1 to 2 min at the point of injury without application of manual pressure on the wounded area.

Congenital Afibrinogenemia and Hypofibrinogenemia: Laboratory and Genetic Testing in Rare Bleeding Disorders with Life-Threatening Clinical Manifestations and Challenging Management

Congenital fibrinogen disorders are rare pathologies of the hemostasis, comprising quantitative (afibrinogenemia, hypofibrinogenemia) and qualitative (dysfibrinogenemia and hypodysfibrinogenemia) disorders. The clinical phenotype is highly heterogeneous, being associated with bleeding, thrombosis, or absence of symptoms. Afibrinogenemia and hypofibrinogenemia are the consequence of mutations in the homozygous, heterozygous, or compound heterozygous state in one of three genes encoding the fibrinogen chains, which can affect the synthesis, assembly, intracellular processing, stability, or secretion of fibrinogen. In addition to standard coagulation tests depending on the formation of fibrin, diagnostics also includes global coagulation assays, which are effective in monitoring the management of replacement therapy. Genetic testing is a key point for confirming the clinical diagnosis. The identification of the precise genetic mutations of congenital fibrinogen disorders is of value to permit early testing of other at risk persons and better understand the correlation between clinical phenotype and genotype. Management of patients with afibrinogenemia is particularly challenging since there are no data from evidence-based medicine studies. Fibrinogen concentrate is used to treat bleeding, whereas for the treatment of thrombotic complications, administered low-molecular-weight heparin is most often. This review deals with updated information about afibrinogenemia and hypofibrinogenemia, contributing to the early diagnosis and effective treatment of these disorders.

Coagulopathies in Intensive Care Medicine: Balancing Act between Thrombosis and Bleeding

Patient Blood Management advocates an individualized treatment approach, tailored to each patient's needs, in order to reduce unnecessary exposure to allogeneic blood products. The optimization of hemostasis and minimization of blood loss is of high importance when it comes to critical care patients, as coagulopathies are a common phenomenon among them and may significantly impact morbidity and mortality. Treating coagulopathies is complex as thrombotic and hemorrhagic conditions may coexist and the medications at hand to modulate hemostasis can be powerful. The cornerstones of coagulation management are an appropriate patient evaluation, including the individual risk of bleeding weighed against the risk of thrombosis, a proper diagnostic work-up of the coagulopathy's etiology, treatment with targeted therapies, and transfusion of blood product components when clinically indicated in a goal-directed manner. In this article, we will outline various reasons for coagulopathy in critical care patients to highlight the aspects that need special consideration. The treatment options outlined in this article include anticoagulation, anticoagulant reversal, clotting factor concentrates, antifibrinolytic agents, desmopressin, fresh frozen plasma, and platelets. This article outlines concepts with the aim of the minimization of complications associated with coagulopathies in critically ill patients. Hereditary coagulopathies will be omitted in this review.

The emergency department evaluation and management of massive hemoptysis

INTRODUCTION

Massive hemoptysis is a life-threatening emergency that requires rapid evaluation and management. Recognition of this deadly condition, knowledge of the initial resuscitation and diagnostic evaluation, and communication with consultants capable of definitive management are key to successful treatment.

OBJECTIVE

The objective of this narrative review is to provide an evidence-based review on the management of massive hemoptysis for the emergency clinician.

DISCUSSION

Rapid diagnosis and management of life-threatening hemoptysis is key to patient survival. The majority of cases arise from the bronchial arterial system, which is under systemic blood pressure. Initial management includes patient and airway stabilization, reversal of coagulopathy, and identification of the source of bleeding using computed tomography angiogram. Bronchial artery embolization with interventional radiology has become the mainstay of treatment; however, unstable patients may require advanced bronchoscopic procedures to treat or temporize while additional information and treatment can be directed at the underlying pathology.

CONCLUSION

Massive hemoptysis is a life-threatening condition that emergency clinicians must be prepared to manage. Emergency clinicians should focus their management on immediate resuscitation, airway preservation often including intubation and isolation of the non-bleeding lung, and coordination of definitive management with available consultants including interventional radiology, interventional pulmonology, and thoracic surgery.

Role of thromboelastography in the evaluation of septic shock patients with normal prothrombin time and activated partial thromboplastin time

Coagulopathy is frequent in septic shock and plays a key role in multiple organ dysfunction. The aim of this study is to investigate application values of thromboelastography (TEG) for outcome in septic shock patients with a normal value of prothrombin time (PT) and active partial thromboplastin time (aPTT). Prospective observational study using 1298 consecutive septic shock patients with TEG at admission was conducted at the emergency department (ED) of a tertiary care hospital in South Korea between 2016 and 2019. After excluding overt-disseminated intravascular coagulation (DIC) defined by scoring system, we included patients with a normal value of international normalized ratio ≤ 1.3 and aPTT ≤ 34 s. The primary outcome was 28-day mortality. 893 patients were included and 129 patients with overt DIC were excluded. Of the 764 remaining patients, 414 (54.2%) patients showed normal PT and aPTT (28-day mortality rate, 11.4%). TEG values such as reaction time, kinetic time (K), alpha angle (α), maximum amplitude (MA) and lysis index (LY 30) showed no significant mean difference between the survivor and non-survivor groups. However, hypocoagulable TEG values such as α < 53° (12.0% vs. 23.4%; p = 0.039), and MA < 50 mm (6.3% vs. 21.3%; p = 0.002) were significantly higher in the non-survived group. In multivariate analysis, hypocoagulable state (defined as K > 3 and α < 53 and MA < 50) was independent factors associated with increased risk of death (OR 4.882 [95% CI, 1.698–14.035]; p = 0.003). In conclusion, septic shock patients with normal PT and aPTT can be associated with impaired TEG profile, such as hypocoagulability, associated with increased mortality.

Fibrinogen Activates PAK1/Cofilin Signaling Pathway to Protect Endothelial Barrier Integrity

INTRODUCTION

We recently demonstrated that fibrinogen stabilizes syndecan-1 on the endothelial cell (EC) surface and contributes to EC barrier protection, though the intracellular signaling pathway remains unclear. P21 (Rac1) activated kinase 1 (PAK1) is a protein kinase involved in intracellular signaling leading to actin cytoskeleton rearrangement and plays an important role in maintaining endothelial barrier integrity. We therefore hypothesized that fibrinogen binding to syndecan-1 activated the PAK1 pathway.

METHODS

Primary human lung microvascular endothelial cells were incubated in 10% lactated Ringers (LR) solution or 10% fibrinogen saline solution (5 mg/mL). Protein phosphorylation was determined by Western blot analysis and endothelial permeability measured by fluorescein isothiocyanate (FITC)-dextran. Cells were silenced by siRNA transfection. Protein concentration was measured in the lung lavages of mice.

RESULTS

Fibrinogen treatment resulted in increased syndecan-1, PAK1 activation (phosphorylation), cofilin activation (dephosphorylation), as well as decreased stress fibers and permeability when compared with LR treatment. Cofilin is an actin-binding protein that depolymerizes F-actin to decrease stress fiber formation. Notably, fibrinogen did not influence myosin light chain activation (phosphorylation), a mediator of EC tension. Silencing of PAK1 prevented fibrinogen-induced dephosphorylation of cofilin and barrier integrity. Moreover, to confirm the in vitro findings, mice underwent hemorrhagic shock and were resuscitated with either LR or fibrinogen. Hemorrhage shock decreased lung p-PAK1 levels and caused significant lung vascular leakage. However, fibrinogen administration increased p-PAK1 expression to near sham levels and remarkably prevented the lung leakage.

CONCLUSION

We have identified a novel pathway by which fibrinogen activates PAK1 signaling to stimulate/dephosphorylate cofilin, leading to disassembly of stress fibers and reduction of endothelial permeability.

Fibrinogen reconstitution after therapeutic apheresis: Comparison of double-filtration plasmapheresis, plasma exchange, and immunoadsorption

BACKGROUND

Fibrinogen reconstitution after therapeutic apheresis has been poorly studied. Apheresis modalities, for example, plasma exchange (PE), double-filtration plasmapheresis (DFPP), or selective immunoadsorption (IA), may have different impacts.

METHODS

We retrospectively investigated therapeutic apheresis sessions performed at our center across four modalities (PE, DFPP, and IA with or without plasma filtration). Fibrinogen levels were assessed at the beginning and end of each apheresis session, and immediately before the subsequent session. We adjusted measurements on hematocrit values to account for hemoconcentration.

RESULTS

Between January 10, 2016 and March 2, 2020, we included 90 patients for a total of 754 apheresis sessions (PE: 35; DFPP: 351; IA only: 109; IA + plasma filtration: 259). Each patient received a median of five sessions (1Q 3; 3Q 9); median plasma volume treated was 5.5 L (1Q 4.3 L; 3Q 7.0 L). Within a session, DFPP and PE induced a significantly greater depletion of fibrinogen than both IA modalities, even after adjustment for the treated plasma volume. Median fibrinogen reconstitution was 0.8 (0.4-1.2) g/L (median time between sessions: 38 hours). In multivariate analysis, fibrinogen reconstitution was significantly associated with intersession time (+0.66 g/L/log-hour P < .001), apheresis modality (ANOVA; P < .001), initial fibrinogen concentration (+0.15 g/L per gram of fibrinogen; P < .001), and the last fibrinogen concentration from the previous apheresis session (-0.14 g/L per gram of fibrinogen; P < .001). In a model that considered hemoconcentration, the results were unchanged.

CONCLUSIONS

We demonstrate that fibrinogen reconstitution was highly variable between patients and apheresis sessions. Apheresis modalities had a significant impact on fibrinogen reconstitution, regardless of hemoconcentration.

The role of cryoprecipitate in human and canine transfusion medicine

OBJECTIVE

To evaluate the current role of cryoprecipitate in human and canine transfusion medicine.

DATA SOURCES

Human and veterinary scientific reviews and original studies found using PubMed and CAB Abstract search engines were reviewed.

HUMAN DATA SYNTHESIS

In the human critical care setting, cryoprecipitate is predominantly used for fibrinogen replenishment in bleeding patients with acute traumatic coagulopathy. Other coagulopathic patient cohorts for whom cryoprecipitate is recommended include those undergoing cardiovascular or obstetric procedures or patients bleeding from advanced liver disease. Preferential selection of cryoprecipitate versus fibrinogen concentrate (when available) is currently being investigated. Also a matter of ongoing debate is whether to administer this product as part of a fixed-dose massive hemorrhage protocol or to incorporate it into a goal-directed transfusion algorithm applied to the individual bleeding patient.

VETERINARY DATA SYNTHESIS

Although there are sporadic reports of the use of cryoprecipitate in dogs with heritable coagulopathies, there are few to no data pertaining to its use in acquired hypofibrinogenemic states. Low fibrinogen in dogs (as in people) has been documented with acute traumatic coagulopathy, advanced liver disease, and disseminated intravascular coagulation. Bleeding secondary to these hypocoagulable states may be amenable to cryoprecipitate therapy. Indications for preferential selection of cryoprecipitate (versus fresh frozen plasma) remain to be determined.

CONCLUSIONS

In the United States, cryoprecipitate remains the standard of care for fibrinogen replenishment in the bleeding human trauma patient. Its preferential selection for this purpose is the subject of several ongoing human clinical trials. Timely incorporation of cryoprecipitate into the transfusion protocol of the individual bleeding patient with hypofibrinogenemia may conserve blood products, mitigate adverse transfusion-related events, and improve patient outcomes. Cryoprecipitate is readily available, effective, and safe for use in dogs. The role of this blood product in clinical canine patients with acquired coagulopathy remains unknown.

Managing the coagulopathy associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has allowed for significant surgical advancements, but accompanying risks can be significant and must be expertly managed. One of the foremost risks is coagulopathic bleeding. Increasing levels of bleeding in cardiac surgical patients at the time of separation from CPB are associated with poor outcomes and mortality. CPB-associated coagulopathy is typically multifactorial and rarely due to inadequate reversal of systemic heparin alone. The components of the bypass circuit induce systemic inflammation and multiple disturbances of the coagulation and fibrinolytic systems. Anticipating coagulopathy is the first step in managing it, and specific patient and procedural risk factors have been identified as predictors of excessive bleeding. Medication management pre-procedure is critical, as patients undergoing cardiac surgery are commonly on anticoagulants or antiplatelet agents. Important adjuncts to avoid transfusion include antifibrinolytics, and perfusion practices such as red cell salvage, sequestration, and retrograde autologous priming of the bypass circuit have varying degrees of evidence supporting their use. Understanding the patient's coagulation status helps target product replacement and avoid larger volume transfusion. There is increasing recognition of the role of point-of-care viscoelastic and functional platelet testing. Common pitfalls in the management of post-CPB coagulopathy include overdosing protamine for heparin reversal, imperfect laboratory measures of thrombin generation that result in normal or near-normal laboratory results in the presence of continued bleeding, and delayed recognition of surgical bleeding. While challenging, the effective management of CPB-associated coagulopathy can significantly improve patient outcomes.

Transfusion in Pediatric Patients: Review of Evidence-Based Guidelines

Children require transfusion of blood components for a vast array of medical conditions, including acute hemorrhage, hematologic and nonhematologic malignancies, hemoglobinopathy, and allogeneic and autologous stem cell transplant. Evidence-based literature on pediatric transfusion practices is limited, particularly for non-red blood cell products, and many recommendations are extrapolated from studies in adult populations. Recognition of these knowledge gaps has led to increasing numbers of clinical trials focusing on children and establishment of pediatric transfusion working groups in recent years. This article reviews existing literature on pediatric transfusion therapy within the larger context of analogous data in adult populations.

Paradoxical pulmonary hemorrhage associated with hemocoagulase batroxobin in a patient with hemoptysis: A CARE-compliant case report

RATIONAL

Hemocoagulase, a hemostatic, is used in patients with trauma, gastrointestinal bleeding, or pulmonary hemorrhage or those undergoing surgery. However, paradoxical bleeding after hemocoagulase administration is not considered a clinically significant adverse effect. Here, we report a case of paradoxical pulmonary hemorrhage associated with hypofibrinogenemia after administration of the hemocoagulase batroxobin in a patient with hemoptysis.

PATIENT CONCERNS

An 86-year-old woman complained of hemoptysis during hospitalization with organophosphate poisoning. Hemocoagulase was administered to manage bleeding; however, bleeding signs, such as hemoptysis, massive epistaxis, and ecchymosis, recurred.

DIAGNOSES

The patient was diagnosed with acquired hypofibrinogenemia on the basis of the reduced plasma fibrinogen level after hemocoagulase administration and lack of other causes of bleeding.

INTERVENTION

Hemocoagulase administration was discontinued, and fibrinogen-containing plasma products were administered.

OUTCOMES

The plasma fibrinogen level normalized and bleeding signs did not recur.

LESSONS

It is necessary to measure plasma fibrinogen levels regularly in patients undergoing hemocoagulase administration and discontinue its administration when acquired hypofibrinogenemia is detected.

Fibrinogen Albumin Ratio and Ischemic Stroke During Venoarterial Extracorporeal Membrane Oxygenation

Fibrinogen is a clotting factor and a major determinant of platelet aggregation. Albumin, on the other hand, inhibits platelet function and thrombus formation. Taken together, an elevated fibrinogen albumin ratio (FAR) has been described as a marker of disease severity during prothrombotic conditions. We evaluated the association of FAR and ischemic stroke during venoarterial extracorporeal membrane oxygenation (VA ECMO) support. A single center, retrospective study was performed including all adult patients placed on VA ECMO. FAR was calculated from fibrinogen and albumin measurements in the first 24 hours of VA-ECMO initiation. Patients were categorized into high (≥125) and low (<125) FAR groups and the risk of eventual ischemic stroke was determined. There were 201 patients who underwent VA ECMO placement and 157 had a FAR. They were 56 ± 14 years old and 66 (42%) had a high FAR. Patients with a high FAR had lower survival free from an ischemic stroke during VA ECMO (log rank p < 0.001; adjusted hazard ratio 5.51; 95% CI: 1.8-16.5). In tertile analysis, the level of FAR was associated with an incrementally higher likelihood of eventual ischemic stroke (log rank p = 0.004). Those with a high FAR had greater mean platelet volume (10.8[10.4-12] vs. 10.5[10.2-11.9]fl, p = 0.004). An elevated FAR during the first 24 hours of VA ECMO placement is associated with a greater risk of a subsequent ischemic stroke. Our findings suggest that assessment of FAR soon after VA ECMO placement may assist with early stratification of patients at risk for an ischemic stroke.

Hypofibrinogenemia induced by high-dose tigecycline-case report and review of literature

RATIONALE

Extensive off-label use may affect the safety profile of tigecycline. Tigecycline-associated hypofibrinogenemia is potentially life threatening, although the frequency of life-threatening reactions is unknown and their incidence is easily overlooked. We report a case of 2 instances of treatment with high-dose tigecycline, each of which presented with hypofibrinogenemia.

PATIENT CONCERNS

An 86-year-old male patient was treated twice with high-dose tigecycline and presented with hypofibrinogenemia both times. The decrease in fibrinogen occurred within 3 to 7 days of tigecycline treatment. Other coagulation parameters had slightly prolonged values.

DIAGNOSES

Coagulopathy and hypofibrinogenemia.

INTERVENTIONS

We discontinued the tigecycline.

OUTCOMES

The fibrinogen level normalized within 5 days after the withdrawal of tigecycline. Following 80 days of hospitalization, the patient was transferred to the rehabilitation hospital for further treatment.

LESSONS

We suggest routine strict monitoring of coagulation parameters, particularly fibrinogen. Attention should be paid to below-normal fibrinogen levels due to increased bleeding risk and severity of reaction at fibrinogen levels below 1 g/L.

COVID-19 Associated Coagulopathy and Implications for its Treatment

The SARS-CoV-2 coronavirus (COVID-19) pandemic is due to lack of prior immunity and there is no certain management, regarding the complications of this viral illness. The target organ for COVID-19 infection are the lungs. Patients may develop acute lung injury that can be complicated by acute respiratory failure, as well as multiorgan failure. The pathophysiology of COVID-19 infection is characterized with inflammatory changes, associated with coagulopathy. Recent data suggests diffuse bilateral pulmonary inflammation observed in COVID-19 infection that is related to a novel pulmonary-specific vasculopathy, defined as pulmonary intravascular coagulopathy (PIC), distinct from disseminated intravascular coagulopathy (DIC). The coagulopathy associated with COVID-19 is distinguished by initial elevation of D-dimer and fibrin/fibrinogen degradation products. Abnormalities in prothrombin time (PT), partial thromboplastin time (APTT) and platelet counts are not common in the early stages of the infection. This suggests the early screening measurement of D-dimer and fibrinogen. The implications for COVID-19-associated-coagulopathy is the established thromboembolic prophylaxis and standard management for sepsis-induced coagulopathy or DIC. High levels of D-dimer are a marker of higher mortality risk. However, current studies do not show the common use of full therapeutical doses of anticoagulants, unless there are other clinical indications. Bleeding in COVID-19 infection is uncommon, even when a laboratory constellation for DIC is present. However, if it occurs, standard guidelines for DIC management should be followed.

Haematological manifestations, mechanisms of thrombosis and anti-coagulation in COVID-19 disease: A review

Coronavirus-19 disease (COVID-19), a zoonosis, was first reported in the city of Wuhan, province of Hubei, China in December 2019. The disease is caused by the Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2). As of 12th of May 2020, 4,256,022 confirmed cases affecting 212 countries with 287,332 deaths have been reported. The common symptoms reported in patients with COVID-19 are fever, dry cough, dyspnoea and gastrointestinal symptoms such as vomiting and diarrhoea. Non-survivors often succumb due to widespread pulmonary intravascular coagulopathy, arterial and venous thromboembolism, disseminated intravascular coagulopathy (DIC), secondary hemophagocytic lymphohistiocytosis (sHLH), and multiorgan dysfunctional syndrome (MODS). All hospitalised patients should be monitored closely for thrombotic events. Patients who develop bleeding episodes should be managed according to standard DIC guidelines. The main objectives of this review are 1) to provide a succinct background of this novel disease 2) discuss the haematological presentations and mechanisms of thrombosis 3) emphasize the role of anti-coagulation prophylaxis 4) explore the management of coagulopathy 5) provide insight on management of patients with COVID-19 disease and pre-existing bleeding disorders.

Trauma of major surgery: A global problem that is not going away

Globally, a staggering 310 million major surgeries are performed each year; around 40 to 50 million in USA and 20 million in Europe. It is estimated that 1–4% of these patients will die, up to 15% will have serious postoperative morbidity, and 5–15% will be readmitted within 30 days. An annual global mortality of around 8 million patients places major surgery comparable with the leading causes of death from cardiovascular disease and stroke, cancer and injury. If surgical complications were classified as a pandemic, like HIV/AIDS or coronavirus (COVID-19), developed countries would work together and devise an immediate action plan and allocate resources to address it. Seeking to reduce preventable deaths and post-surgical complications would save billions of dollars in healthcare costs. Part of the global problem resides in differences in institutional practice patterns in high- and low-income countries, and part from a lack of effective perioperative drug therapies to protect the patient from surgical stress. We briefly review the history of surgical stress and provide a path forward from a systems-based approach. Key to progress is recognizing that the anesthetized brain is still physiologically ‘awake’ and responsive to the sterile stressors of surgery. New intravenous drug therapies are urgently required after anesthesia and before the first incision to prevent the brain from switching to sympathetic overdrive and activating secondary injury progression such as hyperinflammation, coagulopathy, immune activation and metabolic dysfunction. A systems-based approach targeting central nervous system-mitochondrial coupling may help drive research to improve outcomes following major surgery in civilian and military medicine.

Predictor parameters for poor prognosis in patients with sudden sensorineural hearing loss: fibrinogen to albumin ratio vs C-reactive protein to albumin ratio

Introduction

Prognosis of sudden sensorineural hearing loss may be predicted using several parameters of laboratory blood analysis.

Objective

To identify and investigate the most significant indicator parameters related to the poor prognosis of sudden sensorineural hearing loss.

Methods

Eighty-eight patients were included, and three groups were constituted: non-recovery group with14 patients, recovery group with 33 patients and control group with 41 individuals. We compared fibrinogen-to-albumin ratio, C-reactive protein-to-albumin ratio, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, white blood cell and hemoglobin of the groups. Then, we investigated the most significant indicator parameters related to the poor prognosis of sudden hearing loss.

Results

The mean hemoglobin, mean platelet-lymphocyte ratio and median white blood cell values did not significantly differ among three groups (p = 0.36, p = 0.86 and p = 0.79, respectively). A significant difference of median fibrinogen-albumin ratio, C-reactive protein-albumin ratio, neutrophil-to-lymphocyte ratio was evident among three groups (p < 0.001, p = 0.003 and p = 0.002, respectively). Median fibrinogen-albumin ratio, C-reactive protein-albumin ratio and neutrophil-to-lymphocyte ratio values were significantly greater in the non-recovery group, compared with the controls (p < 0.001, p = 0.003 and p = 0.005, respectively). Median fibrinogen-to-albumin ratio, C-reactive protein-to-albumin ratio and neutrophil-to-lymphocyte ratio were significantly greater in the recovery group, compared with the controls (p < 0.001, p = 0.013 and p = 0.005, respectively). Moreover, the median fibrinogen-albumin ratio was significantly greater in the non-recovery group compared with the recovery group (p = 0.017). However, no statistically significant difference of median C-reactive protein-albumin ratio, neutrophil-to-lymphocyte was evident between the non-recovery and recovery groups (p = 0.15).

Conclusion

Increased levels of fibrinogen-albumin ratio may be predictive for poor prognosis in patients with sudden sensorineural hearing loss.

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.

Neurological involvement of coronavirus disease 2019: a systematic review

Background

In December 2019, unexplained cases of pneumonia emerged in Wuhan, China, which were found to be secondary to the novel coronavirus SARS-CoV-2. On March 11, 2020, the WHO declared the Coronavirus Disease 2019 (COVID-2019) outbreak, a pandemic.

Objective

To clarify the neurological complications of SARS-CoV-2 infection including the potential mechanisms and therapeutic options.

Methods

We conducted a systematic literature search from December 01, 2019 to May 14, 2020 using multiple combinations of keywords from PubMed and Ovid Medline databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included articles with cases of COVID-19 where neurological involvement was evident.

Results

We were able to identify 82 cases of COVID-19 with neurological complications. The mean age was 62.3 years. 37.8% of the patients were women (n = 31). 48.8% of the patients (n = 40) had cerebrovascular insults, 28% (n = 23) had neuromuscular disorders, and 23% of the patients (n = 19) had encephalitis or encephalopathy.

Conclusions

Neurological manifestations of COVID-19 are not rare, especially large vessel stroke, Guillain–Barre syndrome, and meningoencephalitis. Moving forward, further studies are needed to clarify the prevalence of the neurological complications of SARS-CoV-2 infection, investigate their biological backgrounds, and test treatment options. Physicians should be cautious not to overlook other neurological diagnoses that can mimic COVID-19 during the pandemic.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09990-2) contains supplementary material, which is available to authorized users.

COVID-19 and its implications for thrombosis and anticoagulation

Severe acute respiratory syndrome coronavirus 2, coronavirus disease 2019 (COVID-19)-induced infection can be associated with a coagulopathy, findings consistent with infection-induced inflammatory changes as observed in patients with disseminated intravascular coagulopathy (DIC). The lack of prior immunity to COVID-19 has resulted in large numbers of infected patients across the globe and uncertainty regarding management of the complications that arise in the course of this viral illness. The lungs are the target organ for COVID-19; patients develop acute lung injury that can progress to respiratory failure, although multiorgan failure can also occur. The initial coagulopathy of COVID-19 presents with prominent elevation of D-dimer and fibrin/fibrinogen-degradation products, whereas abnormalities in prothrombin time, partial thromboplastin time, and platelet counts are relatively uncommon in initial presentations. Coagulation test screening, including the measurement of D-dimer and fibrinogen levels, is suggested. COVID-19-associated coagulopathy should be managed as it would be for any critically ill patient, following the established practice of using thromboembolic prophylaxis for critically ill hospitalized patients, and standard supportive care measures for those with sepsis-induced coagulopathy or DIC. Although D-dimer, sepsis physiology, and consumptive coagulopathy are indicators of mortality, current data do not suggest the use of full-intensity anticoagulation doses unless otherwise clinically indicated. Even though there is an associated coagulopathy with COVID-19, bleeding manifestations, even in those with DIC, have not been reported. If bleeding does occur, standard guidelines for the management of DIC and bleeding should be followed.

The effect of hematocrit, fibrinogen concentration and temperature on the kinetics of clot formation of whole blood

BACKGROUND

Dynamic mechanical analysis of blood clots can be used to detect the coagulability of blood.

OBJECTIVE

We investigated the kinetics of clot formation by changing several blood components, and we looked into the clot "signature" at its equilibrium state by using viscoelastic and dielectric protocols.

METHODS

Oscillating shear rheometry, ROTEM, and a dielectro-rheological device was used.

RESULTS

In fibrinogen- spiked samples we found the classical high clotting ability: shortened onset, faster rate of clotting, and higher plateau stiffness. Electron microscopy explained the gain of stiffness. Incorporated RBCs weakened the clots. Reduction of temperature during the clotting process supported the development of high moduli by providing more time for fiber assembly. But at low HCT, clot firmness could be increased by elevating the temperature from 32 to 37°C. In contrast, when the fibrinogen concentration was modified, acceleration of clotting via temperature always reduced clot stiffness, whatever the initial fibrinogen concentration. Electrical resistance increased continuously during clotting; loss tangent (D) (relaxation frequency 249 kHz) decreased when clots became denser: fewer dipoles contributed to the relaxation process. The relaxation peak (Dmax) shifted to lower frequencies at higher platelet count.

CONCLUSION

Increasing temperature accelerates clot formation but weakens clots. Rheometry and ROTEM correlate well.