Functional Fibrinogen Levels Research Articles

A single-center, retrospective analysis to compare measurement of fibrinogen using the TEG6 analyzer to the Clauss measurement in children undergoing heart surgery.

Newer generation viscoelastic tests, TEG6s, offer point-of-care hemostatic therapy in adult patients. However, their efficacy in estimating fibrinogen levels in pediatric patients undergoing cardiac surgery is not well established. This study evaluates TEG6s for estimating fibrinogen levels in pediatric cardiac surgery patients and its predictive capability for post-bypass hypofibrinogenemia. A single-center, retrospective study on pediatric patients (under 18 years) who underwent cardiac surgery with cardiopulmonary bypass from August 2020 and November 2022. Blood samples for estimated whole blood functional fibrinogen level via TEG6s (Haemonetics Inc.) and concurrent laboratory-measured plasma fibrinogen via von Clauss assay were collected at pre- and post-cardiopulmonary bypass. Paired data for TEG6s estimated functional fibrinogen levels and plasma fibrinogen were analyzed for 432 pediatric patients pre-bypass. It was observed that functional fibrinogen consistently overestimated plasma fibrinogen across all age groups with a mean difference of 138 mg/dL (95% confidence interval [CI]: 128-149 mg/dL). This positive bias in the pre-bypass data was confirmed by Bland-Altman analysis. Post-bypass, functional fibrinogen estimates were comparable to plasma fibrinogen in all patient groups with a mean difference of -6 mg/dL (95% CI: -20-8 mg/dL) except for neonates, where functional fibrinogen levels underestimated plasma fibrinogen with a mean difference of -38 mg/dL (95% CI: -64 to -12 mg/dL). The predictive accuracy of functional fibrinogen for detecting post-bypass hypofibrinogenemia (plasma fibrinogen ≤250 mg/dL) demonstrated overall fair accuracy in all patients, indicated by an area under the curve of 0.73 (95% CI: 0.65-0.80) and good accuracy among infants, with an area under the curve of 0.80 (95% CI: 0.70-0.90). Similar performance was observed in predicting critical post-bypass hypofibrinogenemia (plasma fibrinogen ≤200 mg/dL). Based on these analyses, optimal cutoffs for predicting post-bypass hypofibrinogenemia were established as a functional fibrinogen level ≤270 mg/dL and MAFF ≤15 mm. This study demonstrates that whole blood functional fibrinogen, as estimated by TEG6s, tends to overestimate baseline plasma fibrinogen levels in pediatric age groups but aligns more accurately post-cardiopulmonary bypass, particularly in neonates and infants, suggesting its potential as a point-of-care tool in pediatric cardiac surgery. However, the variability in TEG6s performance before and after bypass highlights the need for careful interpretation of its results in clinical decision-making. Despite its contributions to understanding TEG6s in pediatric cardiac surgery, the study's design and inherent biases warrant cautious application of these findings in clinical settings.

Post-Marketing Observational Study of the Safety and Efficacy of Fibrinogen Concentrate in Congenital Fibrinogen Deficiency in Patients of All Ages

Background and Significance: Congenital fibrinogen deficiency (CFD) is a rare coagulation disorder characterized by a lack or low levels of functional fibrinogen leading to inadequate clot formation. Patients with CFD may experience severe or frequent bleeding episodes (BEs), either spontaneously or following trauma or surgery. Human fibrinogen concentrate (HFC; Fibryga® [Octapharma]) can restore hemostasis, and its efficacy and safety has been demonstrated in interventional clinical studies of adult and pediatric patients. The primary objective of this planned observational study is to collect real-world evidence to further assess the safety profile of this HFC, in patients of all ages with congenital fibrinogen deficiency, by characterizing the risks of thrombosis and anaphylaxis following its administration for treatment of bleeding (Figure 1). The observational data collected in this study will provide a more comprehensive safety profile of this HFC in patients of all ages following its marketing authorization. Study Design and Methods: FORMA-07 (NCT03793426) is a prospective, non-interventional, multicenter, observational, post-marketing study. Patients of all ages with a documented diagnosis of CFD (i.e., congenital afibrinogenemia or hypofibrinogenemia) requiring on demand HFC for BE treatment are eligible for inclusion (Table 1). Exclusion criteria include other coagulation disorders, history of anti-fibrinogen inhibitors, and participation in concurrent clinical studies. This study will examine a highly purified, plasma derived, double virus inactivated/eliminated, lyophilized HFC, which will be used according to individual country approval and labelling, and individually dosed as per the locally approved package insert. Independent ethical committee approval will be sought prior to study start and freely given, written informed consent obtained from all participants, or legal guardians in the case of pediatric patients. This study will be conducted in accordance with the ethical principles laid down in the Declaration of Helsinki. The primary endpoint is the incidence of thromboembolic adverse drug reactions (ADRs) . Serious ADRs, ADRs of special interest (including thromboembolic events and anaphylaxis), and thromboembolic monitoring using the Wells Score will be documented. Hemostatic efficacy will be assessed as a secondary endpoint by the study investigator using a robust 4-point objective scale from 2 to 24 hours following treatment. FORMA-07 is ongoing and actively enrolling patients of all ages with CFD. The study aims to enroll ~25 patients over 7 years, collecting data from 105 BEs (≥10 major BEs in 10 patients). Results of HFC safety and efficacy will be continually monitored throughout the study. Completion is expected Q4 2027.

Hemostatic system in Takotsubo patients at long-term follow-up: A hidden activation?

BackgroundTakotsubo cardiomyopathy (TTS) has long been considered a benign condition, despite recurrent events and long-term adverse outcomes are often reported. Endothelial damage, blood hyperviscosity, and platelet activation described in acute phase persist in long-term follow-up; however, TTS pathophysiology is still not fully understood. Here, we explored the hemostatic system at a median of 3.1 years after TTS to uncover additional long-lasting changes in these patients. MethodsWe assessed hemostatic parameters in women with TTS (n = 23) or coronary artery disease (CAD; n = 31) and in control women (n = 26) age-matched, by thromboelastographic analysis, prothrombin time (PT) and partial thromboplastin time (aPTT) coagulation assays and microparticle exposing Tissue Factor (MP-TF). Functional fibrinogen and fibrin polymerization were analyzed by Clauss method and spectrophotometry, respectively. Platelet reactivity was evaluated by light transmission aggregometry, whereas plasminogen activator inhibitor-1 (PAI-1) and brain-derived neurotrophic factor (BDNF) were measured by ELISA kit. ResultsCompared with control subjects, TTS patients exhibit an accelerated clot formation, higher percentage of fibrin polymerization and higher PAI-1 levels. Compared with CAD, TTS patients showed sustained residual platelet activation but decreased functional fibrinogen, fibrin polymerization and MP-TF levels, prolonged aPTT and a marked BDNF increase. ConclusionsThe long-term activation of hemostatic system observed in TTS patients compared to control subjects suggests a persistent humoral abnormality that may be related to the propensity for TTS recurrence. The higher residual platelet activity observed in TTS than in CAD patients invites investigation on TTS-tailored antiplatelet therapy potentially needed to prevent TTS adverse outcomes.

Levels of Fibrinogen Variants Are Altered in Severe COVID-19.

Background Fibrinogen variants as a result of alternative messenger RNA splicing or protein degradation can affect fibrin(ogen) functions. The levels of these variants might be altered during coronavirus disease 2019 (COVID-19), potentially affecting disease severity or the thrombosis risk. Aim To investigate the levels of fibrinogen variants in plasma of patients with COVID-19. Methods In this case-control study, we measured levels of functional fibrinogen using the Clauss assay. Enzyme-linked immunosorbent assays were used to measure antigen levels of total, intact (nondegraded Aα chain), extended Aα chain (α E ), and γ' fibrinogen in healthy controls, patients with pneumococcal infection in the intensive care unit (ICU), ward patients with COVID-19, and ICU patients with COVID-19 (with and without thrombosis, two time points). Results Healthy controls and ward patients with COVID-19 ( n = 10) showed similar fibrinogen (variant) levels. ICU patients with COVID-19 who later did ( n = 19) or did not develop thrombosis ( n = 18) and ICU patients with pneumococcal infection ( n = 6) had higher absolute levels of functional, total, intact, and α E fibrinogen than healthy controls ( n = 7). The relative α E fibrinogen levels were higher in ICU patients with COVID-19 than in healthy controls, while relative γ' fibrinogen levels were lower. After diagnosis of thrombosis, only the functional fibrinogen levels were higher in ICU patients with COVID-19 and thrombosis than in those without, while no differences were observed in the other fibrinogen variants. Conclusion Our results show that severe COVID-19 is associated with increased levels of α E fibrinogen and decreased relative levels of γ' fibrinogen, which may be a cause or consequence of severe disease, but this is not associated with the development of thrombosis.

The qLabs® FIB system, a novel point-of-care technology for a rapid and accurate quantification of functional fibrinogen concentration from a single drop of citrated whole blood

Hypofibrinogenemia is often associated with excessive bleeding and requires immediate treatment. The qLabs FIB® is a handheld and easy-to-use point-of-care (POC) device designed for the rapid measurement of functional fibrinogen concentration from a single drop of citrated whole blood. The aim of this study was to evaluate the analytical performances of the qLabs FIB system.Fibrinogen concentrations from 110 citrated whole blood specimen were measured by both the qLabs FIB and the Clauss laboratory reference methods (STA®-Liquid Fib assay on STA-R® Max from Stago). A three-laboratories comparison study was conducted to assess reproducibility and repeatability of the qLabs FIB using plasma quality control material. In addition, single-site assays were conducted to assess the repeatability from citrated whole blood specimen covering the qLabs FIB reportable range.A very strong correlation between the qLabs FIB and the Clauss laboratory reference method was observed (r = 0.95). Using a clinical cut-off value of 2.0 g/L, the area under the receiver operating characteristic curve (ROC) of citrated whole blood was 0.99 and sensibility and specificity were 100 % and 93.5 %, respectively. Percent CVs for reproducibility and repeatability assessed from quality control material, were both <5 %. Repeatability assessed from citrated whole blood specimen showed a CV of 2.6 to 6.5 %.In conclusion, the qLabs FIB system enables a rapid and reliable measurement of functional fibrinogen levels from citrated whole blood and exhibits a strong prediction power at the 2 g/L clinical cut-off when compared to the Clauss laboratory reference. Further clinical studies should demonstrate its ability to quickly confirm the diagnosis of acquired hypofibrinogenemia and help identify patients who may benefit from targeted hemostatic treatment.

Potential for prolongation of fibrinogen concentrates post-reconstitution

Background and objectivesReconstituted fibrinogen concentrate is considered stable for 8–24 h based on product monographs. Given the long half-life of fibrinogen in vivo (3–4 days), we hypothesized that reconstituted sterile fibrinogen protein would remain stable longer than 8–24 h. Extending the expiry date for reconstituted fibrinogen concentrate could decrease wastage and facilitate reconstitution in advance to minimize turnaround times. We performed a pilot study to define the stability of reconstituted fibrinogen concentrates over time. Materials and methodsReconstituted Fibryga® (Octapharma AG) from 64 vials was stored in the temperature-controlled refrigerator (4 °C) for up to 7 days with functional fibrinogen concentration measured serially using the automated Clauss method. The samples were frozen, then thawed and diluted with pooled normal plasma in order for them to be batch tested. ResultsReconstituted fibrinogen samples stored in the refrigerator showed no significant reduction in functional fibrinogen concentration for the entire 7-day study period (p = 0.63). Duration of initial freezing had no detrimental effect on functional fibrinogen levels (p = 0.23). ConclusionFibryga® can be stored at 2–8 °C post-reconstitution for up to one week with no loss in functional fibrinogen activity based on Clauss fibrinogen assay. Further studies with other fibrinogen concentrate formulations and clinical in vivo studies may be warranted

Impact of Genetic and Post-Translational Modifications on Structure and Function of Fibrinogen

Introduction: Fibrinogen is a highly heterogeneous protein that is a result of several types of alteration, including genetic polymorphisms, alternative mRNA processing, posttranslational modifications, proteolytic cleavage and environmental factors. The different combinations of these alternations cause a formation of abnormal variants of fibrinogen that may affect the molecule. Fibrinogen is more vulnerable to oxidative stress than other plasmatic proteins. The oxidative post-translational modifications can be caused by different reactive oxygen species (ROS) and change the spatial structure, thus, impaired protein function. Here, we characterized 48 patients, belonging to 30 unrelated families, with fibrinogen mutation. This study aims to understand the behavior of these alternated fibrinogens in blood coagulation. Methods: We investigated these fibrinogens using a wide range of biochemical procedures, including fibrin polymerization, fibrinolysis, fibrinopeptides (Fps) release measurement, tandem mass spectrometry, thromboelastography, protein modeling, and scanning electron microscopy (SEM). Results: Dysfibrinogenemia was diagnosed in 35 cases, mostly in exon 2 of FGA gene, around thrombin cleavage site in N-termini of Aα chain. Hypofibrinogenemia was found in 13 remaining cases. Novel mutations were identified in 7 cases - heterozygous missense BβY416C and BβA68S, homozygous nonsense BβY345*, heterozygous nonsense BβW403*, heterozygous missense FGG c.8G>A, heterozygous missense γT34A, and heterozygous missense γG284E mutations. All patients had decreased levels of functional and/or plasmatic fibrinogen. Functional tests showed abnormal fibrin development in all patients with lower maximal absorbance. Moreover, fibrinopeptide cleavage measurements revealed differences between the release of Fps in patients with mutation in position close or in the binding site od thrombin. The results obtained from SEM were significantly different in fiber thicknesses or average number of fibers per 1µm2. Homology modeling showed the impaired protein structure of BβA68S and γG284E. Mass spectrometry detected several post-translational oxidations of fibrinogen. Conclusion: The results indicate that detected post-translational modifications, induced very likely by ROS, may affect the overall clottability of fibrinogen and clot morphology. Consequently, our study demonstrates that the identification, characterization, and modeling of novel fibrinogen variants brings new knowledge to fibrinogen domain structures and interactions that influence the assembly, secretion and function of this molecule. This work was supported by the project of the Ministry of Health, Czech Republic (00023736).

Diagnostic Value of Aortic Dissection Risk Score, Coagulation Function, and Laboratory Indexes in Acute Aortic Dissection.

Objective This study was aimed at studying the diagnostic value of aortic dissection (AD) risk score, coagulation function, and laboratory indicators in acute aortic dissection (AAD). Methods In this retrospective study, 57 patients with AAD and 57 with an acute coronary syndrome (ACS). During the same period, 50 healthy subjects were selected as the control group admitted to our institution which were assessed for eligibility and recruited. They were assigned to an AD group (AAD patients) and an ACS group (ACS patients). The AD risk scores, coagulation function indexes, and laboratory indexes of the two groups were compared. With digital subtraction angiography- (DSA-) based diagnosis result as the gold standard, the receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of various indexes for AD, and the sensitivity, specificity, and optimal diagnostic value (Youden index) of the diagnostic indexes were calculated. Additionally, the overall blood clot formation strength (MA), clotting factor function (R), platelet function (MAp), and functional fibrinogen (MAf) levels were evaluated. Results AAD risk, AD screening, early diagnosis of AAD, fibrinogen degradation products (FDP), fibrinogen (Fib), prothrombin time (PT), activated partial thromboplastin time (APTT), tenascin C (TN-C), D-dimer (D-D), and N-terminal B-type natriuretic peptide precursor (NT-proBNP) in the three groups were statistically different (P < 0.05). Further pairwise comparisons showed that the AD patients got higher scores of AAD risk, AD screening, and early diagnosis of AAD versus ACS patients (P < 0.05). AD was associated with lower levels of fibrinogen degradation products (FDP) and fibrinogen (Fib), shorter prothrombin time (PT), and activated partial thromboplastin time (APTT) versus ACS (P < 0.05). AD also resulted in higher levels of tenascin C (TN-C), D-dimer (D-D), and N-terminal B-type natriuretic peptide precursor (NT-proBNP) versus ACS (P < 0.05). The three risk scores, various laboratory indicators, and various coagulation function indicators were of high diagnostic values for the diagnosis of AAD (AUC > 0.9, P < 0.05). The sensitivity of the AD screening scale and TN-C expression level to the diagnosis of AAD was up to 100%, and the specificity of TN-C expression level was up to 98.25%. The influencing factors of AAD included Fib, FDP, PT, APTT, D-D, TN-C, and NT-proBNP. MA, MAf, and MAp displayed the same trend and reached the lowest point at T2. R was the opposite and reached the highest point at T2. At T4, a higher Map and a lower MAf were found than before surgery, and R and MA returned to preoperative levels. The positive detection rate of ACS by CT scan was positively correlated with the degree of stenosis (r = 0.814, P < 0.05). Conclusion AD screening scale, TN-C, and FDP are of the highest diagnostic value in the risk score of AD, laboratory indicators, and coagulation function. It has implications for the diagnosis of ADD.

Clinical features and genetic defect in six index patients with congenital fibrinogen disorders: Three novel mutations with one common mutation in Taiwan's population.

Congenital fibrinogen disorders (CFDs) are caused by mutations in fibrinogen-encoding genes, FGA, FGB, and FGG, which lead to quantitative or qualitative abnormalities of fibrinogen. Although the diagnosis of CFDs is based on antigenic and functional level of fibrinogen, few genotypes are clearly correlated with phenotype. In this study, we investigated all of the referred patients diagnosed as CFDs in Taiwan's population between 1995 and 2020. Clinical features, laboratory data and genetic defects were analysed. Functional fibrinogen level was determined by the Clauss method. Antigenic fibrinogen was measured by an enzyme-linked immunosorbent assay. Fibrinogen genes were assessed for mutations by polymerase chain reaction and sequencing. A total of 18 patients from six unrelated families with CFDs were identified. One patient from a consanguineous family was diagnosed as afibrinogenemia type 1A with a novel homozygous frameshift mutation in FGB exon 4. The other five (83.3 %) index patients were all diagnosed as dysfibrinogenemia type 3A caused by two novel and one known mutation. Six (33.3 %) patients from three families had a novel mutation in FGB exon 8. The clinical features and laboratory data were highly variable among these patients with the same mutation. Three novel mutations of CFDs causing afibrinogenemia and dysfibrinogenemia were identified. The point mutation in FGB exon 8 is also a common mutation in Taiwan's population. Considerable phenotypic variability among the patients with an identical mutation was observed.

Thrombogenicity markers for early diagnosis and prognosis in COVID-19: a change from the current paradigm?

Standard biomarkers have been widely used for COVID-19 diagnosis and prognosis. We hypothesize that thrombogenicity metrics measured by thromboelastography will provide better diagnostic and prognostic utility versus standard biomarkers in COVID-19 positive patients. In this observational prospective study, we included 119 hospitalized COVID-19 positive patients and 15 COVID-19 negative patients. On admission, we measured standard biomarkers and thrombogenicity using a novel thromboelastography assay (TEG-6s). In-hospital all-cause death and thrombotic occurrences (thromboembolism, myocardial infarction and stroke) were recorded. Most COVID-19 patients were African--Americans (68%). COVID-19 patients versus COVID-19 negative patients had higher platelet-fibrin clot strength (P-FCS), fibrin clot strength (FCS) and functional fibrinogen level (FLEV) (P ≤ 0.003 for all). The presence of high TEG-6 s metrics better discriminated COVID-19 positive from negative patients. COVID-19 positive patients with sequential organ failure assessment (SOFA) score at least 3 had higher P-FCS, FCS and FLEV than patients with scores less than 3 (P ≤ 0.001 for all comparisons). By multivariate analysis, the in-hospital composite endpoint occurrence of death and thrombotic events was independently associated with SOFA score more than 3 [odds ratio (OR) = 2.9, P = 0.03], diabetes (OR = 3.3, P = 0.02) and FCS > 40 mm (OR = 3.4, P = 0.02).This largest observational study suggested the early diagnostic and prognostic utility of thromboelastography to identify COVID-19 and should be considered hypothesis generating. Our results also support the recent FDA guidance regarding the importance of measurement of whole blood viscoelastic properties in COVID-19 patients. Our findings are consistent with the observation of higher hospitalization rates and poorer outcomes for African--Americans with COVID-19.

A Novel Nonsense Mutation in FGB (c.1421G>A; p.Trp474Ter) in the Beta Chain of Fibrinogen Causing Hypofibrinogenemia with Bleeding Phenotype.

Congenital hypofibrinogenemia is a rare bleeding disorder characterized by a proportional decrease of functional and antigenic fibrinogen levels. Hypofibrinogenemia can be considered the phenotypic expression of heterozygous loss of function mutations occurring within one of the three fibrinogen genes (FGA, FGB, and FGG). Clinical manifestations are highly variable; most patients are usually asymptomatic, but may appear with mild to severe bleeding or thrombotic complications. We have sequenced all exons of the FGA, FGB, and FGG genes using the DNA isolated from the peripheral blood in two unrelated probands with mild hypofibrinogenemia. Coagulation screening, global hemostasis, and functional analysis tests were performed. Molecular modeling was used to predict the defect of synthesis and structural changes of the identified mutation. DNA sequencing revealed a novel heterozygous variant c.1421G>A in exon 8 of the FGB gene encoding a Bβ chain (p.Trp474Ter) in both patients. Clinical data from patients showed bleeding episodes. Protein modelling confirmed changes in the secondary structure of the molecule, with the loss of three β sheet arrangements. As expected by the low fibrinogen levels, turbidity analyses showed a reduced fibrin polymerisation and imaging difference in thickness fibrin fibers. We have to emphasize that our patients have a quantitative fibrinogen disorder; therefore, the reduced function is due to the reduced concentration of fibrinogen, since the Bβ chains carrying the mutation predicted to be retained inside the cell. The study of fibrinogen molecules using protein modelling may help us to understand causality and effect of novel genetic mutations.

Efficacy and Safety of Human Fibrinogen Concentrate for the Treatment of Patients with Congenital Fibrinogen Deficiency: Combined Results of the FORMA-02 and FORMA-04 Clinical Trials

Introduction: Congenital fibrinogen deficiency (CFD) is a rare disorder which results from a complete lack (afibrinogenemia) or low levels (hypofibrinogenemia) of functional fibrinogen. Treatment with human fibrinogen concentrate (HFC) can treat bleeding episodes and prevent blood loss in surgical treatment in patients with CFD. Herein we report combined data from two clinical studies on the efficacy and safety of HFC for the treatment of bleeding episodes (BEs) and surgical prophylaxis in adult, adolescent and pediatric patients. Methods: Both FORMA-02 and FORMA-04 were multinational, multicenter, prospective, open-label, uncontrolled Phase 3 studies for the use of HFC in adult and pediatric patients with CFD. They reported the hemostatic efficacy and safety of human fibrinogen concentrate (HFC: Fibryga® Octapharma) for on-demand treatment of BEs and surgical prophylaxis using objective criteria. Efficacy was assessed by the trial investigators and adjudicated by an independent data monitoring and end-point adjudication committee (IDMEAC). All adverse events (AEs) and serious AEs were recorded. Results: The two studies included a total of 39 patients who received HFC. The median (range) age across both studies was 17 (1-54) years, with 14 pediatric (aged 0-11), 6 adolescent (aged 12-18) and 19 adult patients (aged &amp;gt;18). Treatment of Bleeding Events 32 patients received HFC for the treatment of 99 bleeding events (BEs), 97 minor and 4 major. Of these, 72 were spontaneous, and 27 were due to trauma. 10 BEs occurred in pediatric patients (8 minor, 2 major), and 89 in adult/adolescents (87 minor, 2 major). The mean (±SD) total dose per BE was 65.51 mg/kg (±26.47) for adult/adolescent patients (ages 12-54) and 93.78 (±64.60) for pediatric patients (ages 0-11). Investigator-assessed and IDMEAC rated hemostatic efficacy are shown in Table 1. Overall hemostatic efficacy was rated as success (rating of excellent or good) for 99.0% of BEs by the IDMEAC. Treatment efficacy results were comparable when analyzed by age subgroup of adult (≥18 years), adolescent (&amp;gt;12-&amp;lt;18 years) and in two groups of pediatric patients (&amp;lt;6 years and 6-12 years). Surgical prophylaxis A total of 12 patients received HFC across 15 surgeries (13 minor and 2 major), 3 in pediatric patients (major: splenectomy; minor: circumcision and pulpectomy), and 12 in adults/adolescents (major: eye enucleation with socket reconstruction; minor: knee radioisotope synovectomy [n=2], dental extraction [n=3], circumcision [n=2], excision of circumcision scar bud, root canal operation, skin biopsy, and debridement of superficial necrosis). Mean (±SD) loading dose administered prior to surgery was 77.39 (±20.22) in adult/adolescent patients and 78.50 mg/kg (±27.96) for pediatric patients. Seven surgeries required multiple infusions, with the two major surgeries requiring 5 and 7 maintenance infusions, and the five minor surgeries requiring median (range) 3 (1-4) maintenance infusions. Intra- and post-operative hemostatic efficacy for all surgeries is shown in Table 1. Overall hemostatic efficacy of all the procedures was rated 100% successful by both the investigator and IDMEAC assessment. Safety A total of 101 AEs occurred in 23 patients (59.0%), including 16 serious AEs in 6 patients. Of these, 5 AEs in 4 patients were considered to be possibly related to treatment. These included a mild skin reaction (itchiness and redness), ischemia due to digital microthrombi, peripheral phlebitis of the upper limbs, and a portal vein thrombosis following splenectomy. No allergic/hypersensitivity reactions or deaths were observed during either of the studies. Conclusions: HFC treatment was shown to be efficacious for on-demand treatment of BEs and perioperative prophylaxis in this rare CFD population, across two Phase 3 clinical trials. Efficacy was comparable for adult, adolescent and pediatric patients. A favorable safety profile was seen for the treatment of patients with congenital afibrinogenemia with HFC. Disclosures Djambas Khayat: Octapharma: Research Funding. Kruzhkova:Octapharma: Current Employment. Solomon:Octapharma: Current Employment. Schwartz:Octapharma: Current Employment. Peyvandi:Octapharma: Research Funding. OffLabel Disclosure: On label use: Fibryga for treatment of bleeding episodes Off label use: Use of Fibryga as surgical prophylaxis in the US

Tigecycline Interferes with Fibrinogen Polymerization Independent of Peripheral Interactions with the Coagulation System.

Tigecycline offers broad anti-bacterial coverage for critically ill patients with complicated infections. A described but less researched side effect is coagulopathy. The aim of this study was to test whether tigecycline interferes with fibrinogen polymerization by peripheral interactions. To study the effect of unmetabolized tigecycline, plasma of healthy volunteers were spiked with increasing concentrations of tigecycline. In a second experimental leg, immortalized human liver cells (HepG2) were treated with the same concentrations to test an inhibitory effect of hepatic tigecycline metabolites. Using standard coagulation tests, only the activated thromboplastin time in humane plasma was prolonged with increasing concentrations of tigecycline. Visualization of the fibrin network using confocal live microscopy demonstrated a qualitative difference in tigecycline treated experiments. Thrombelastometry and standard coagulation tests did not indicate an impairment of coagulation. Although the discrepancy between functional and immunologic fibrinogen levels increased in cell culture assays with tigecycline concentration, fibrinogen levels in spiked plasma samples did not show significant differences determined by functional versus immunologic methods. In our in vitro study, we excluded a direct effect of tigecycline in increasing concentrations on blood coagulation in healthy adults. Furthermore, we demonstrated a rapid loss of mitochondrial activity in hepatic cells with supra-therapeutic tigecycline dosages.

Prospective Longitudinal Evaluation of Coagulation with Novel Thromboelastography Technology in Patients After Subarachnoid Hemorrhage: A Pilot Study

There is limited knowledge of whether hypercoagulability is present after subarachnoid hemorrhage (SAH) or about its timing of onset, duration, and severity. To conduct a pilot new-generation thromboelastography (TEG) technology (TEG6s)-based and conventional coagulation test-supported longitudinal assessment of coagulation in patients with SAH. We prospectively enrolled patients with nontraumatic SAH on admission from May 2015 to May 2016. We performed TEG6s measurements and conventional coagulation tests on days 1, 2, 3, 5, 7, 10, and 14 and compared them with TEG6s parameters in healthy volunteers. We studied 14 patients and 72 TEG6s measurements. Of these patients, 10 (71.4%) were admitted to the intensive care unit. Mean age was 57.5 (±14.5) years, Acute Physiology and Chronic Health Evaluation III score 58.2 (±26.6), length of hospital stay was 23 (±11.7) days, and mortality was 14.3%. At baseline, conventional coagulation tests were within normal range. However, TEG6s parameters already showed increased coagulability. Thereafter, alpha angle, reaction time, functional fibrinogen level, and maximum amplitude rapidly and significantly increased (P < 0.01) compared with healthy controls. Ten (71.4%) patients demonstrated a >20% increase in coagulability based on TEG6s parameters from their baseline. Moreover, TEG6s hypercoagulability peaked at day 10 and only showed an initial partial decline towards normal by day 14. Similarly, platelet counts and fibrinogen levels increased over this period (P < 0.01) CONCLUSIONS: Using TEG6s technology, we found significant and progressive hypercoagulability in 70% of patients, with an early dominant contribution from hyperfibrinogenemia and increased fibrin formation and partial contribution from thrombocytosis, beginning on the first day, increasing to peak values by day 10, and then partly declining toward normal by day14.

Point-of-Care Fibrinogen Testing in Pregnancy.

Agreement between estimated fibrinogen concentration via thromboelastography and traditional assays is not established in the parturient. We therefore recruited 56 parturients and performed Clauss and functional fibrinogen level (FLEV) tests. Mean difference of measurements was 36.8 mg/dL (95% CI, 21.8-51.9) with a standard deviation of 52.8 mg/dL. Calculated limits of agreement were 140.2 mg/dL (95% CI, 166.3-114.6) and -66.6 mg/dL (95% CI, -40.8 to -92.5), within the maximum allowable difference of 165 mg/dL. We therefore conclude that while most measurements fell within the limits of agreement, more work is needed to clearly define the role of this test in the obstetric population.

Severe traumatic brain injury is associated with a unique coagulopathy phenotype.

Traumatic brain injury (TBI) patients present on a spectrum from hypocoagulability to hypercoagulability, depending on the injury complexity, severity, and time since injury. Prior studies have found a unique coagulopathy associated with TBI using conventional coagulation assays such as INR; however, few studies have assessed the association of TBI and coagulopathy using viscoelastic assays that comprehensively evaluate the coagulation in whole blood. This study aims to reevaluate the TBI-specific trauma-induced coagulopathy using arrival thrombelastography. Because brain tissue is high in key procoagulant molecules, we hypothesize that isolated TBI is associated with procoagulant and hypofibrinolytic profiles compared with injuries of the torso, extremities, and polytrauma, including TBI. Data are from the prospective Trauma Activation Protocol study. Activated clotting time (ACT), angle, maximum amplitude (MA), 30-minute percent lysis after MA (LY30), and functional fibrinogen levels (FFLEV) were recorded. Patients were categorized into isolated severe TBI (I-TBI), severe TBI with torso and extremity injuries (TBI + TORSO/EXTREMITIES), and isolated torso and extremity injuries (I-TORSO/EXTREMITIES). Poisson regression was used to adjust for multiple confounders. Overall, 572 patients (48 I-TBI, 45 TBI + TORSO/EXTREMITIES, 479 I-TORSO/EXTREMITIES) were included in this analysis. The groups differed in INR, ACT, angle, MA, and FFLEV but not in 30-minute percent lysis. When compared with I-Torso/Extremities, after adjustment for confounders, severe I-TBI was independently associated with ACT less than 128 seconds (relative risk [RR], 1.5; 95% confidence interval [CI], 1.1-2.2), angle less than 65 degrees (RR, 2.2; 95% CI, 1.4-3.6), FFLEV less than 356 (RR, 1.7; 95% CI, 1.2-2.4) but not MA less than 55 mm, hyperfibrinolysis, fibrinolysis shutdown, or partial thromboplastin time (PTT) greater than 30. Severe I-TBI was independently associated with a distinct coagulopathy with delayed clot formation but did not appear to be associated with fibrinolysis abnormalities. Low fibrinogen and longer ACT values associated with I-TBI suggest that early coagulation factor replacement may be indicated in I-TBI patients over empiric antifibrinolytic therapy. Mechanisms triggering coagulopathy in TBI are unique and warrant further investigation. Retrospective cohort study, prognostic, level III.

Molecular and Clinical Aspects of Aα Dysfibrinogenemia in 25 Patients from the Czech Republic

Fibrinogen is a 340 kDA glycoprotein that plays a vital role in the hemostasis. The three pairs of polypeptide chains (Aα, Bβ and γ) form a heterodimer structure of fibrinogen, each chain is encoded by a distinct gene (FGA, FGB and FGG). Congenital dysfibrinogenemia is a rare qualitative disorder characterized by structural alterations in fibrinogen molecule resulting in its defective function. The clinical manifestation of majority cases is asymptomatic (50%); about 30% are associated with bleeding tendencies and only some cases are thrombotic (20%).In this study, we evaluated 25 patients with heterozygous missense mutations in exon 2 of FGA gene from 13 unrelated families, all with low levels of functional fibrinogen and prolonged clotting time. All mutations were located around thrombin cleavage site at N-terminus of a fibrinogen Aα chain. Mutation Aα G13E was found in 6 families (13 patients), Aα R16H in 4 families (6 patients), Aα R16C in 1 family (4 patients), and Aα R19G in 1 family (2 patients). Correlations between the genotype and phenotype were studied by fibrin polymerization, fibrinolysis, kinetics of fibrinopeptides release, and electron and confocal microscopy. The viscoelastic properties of fibrin clots were measured. All mutations caused a delay or absence of fibrinopeptide A release and prolonged fibrin polymerization. Clinical phenotypes of mutations were, unexpectedly and importantly, highly heterogeneous. Out of 25 patients 17 were asymptomatic, 7 had the bleeding tendencies and 1 patient had thrombosis. One woman with Aα G13E had 2 spontaneous abortions and 3 pregnant women with Aα G13E, Aα R16C and Aα R19G mutations suffered for hemorrhages or postpartum bleeding. Eventually, all had successful delivery under provided care with a hematologist. Small surgeries were performed to patients with Aα R16H supplied with fibrinogen concentrates and antifibrinolytics. Our observations show that the patients should be carefully treated based both on the results of the laboratory analyzes and personal and family history.This work was supported by the project of the Ministry of Health, Czech Republic, for conceptual development of research organization 00023736, by Grant from the Academy of Sciences, Czech Republic nr. P205/12/G118, and by ERDF OPPK CZ.2.16/3.1.00/24001. DisclosuresNo relevant conflicts of interest to declare.

Genetics, diagnosis and clinical features of congenital hypodysfibrinogenemia: a systematic literature review and report of a novel mutation

Background Hypodysfibrinogenemia is a rare disease characterized by decreased levels of a dysfunctional fibrinogen. It shares features with both hypo- and dysfibrinogenemia, although with specific molecular patterns and clinical phenotypes. Objectives To better define the genetics, the diagnosis and the clinical features of hypodysfibrinogenemia. Patients/Methods A systematic literature search led to 167 records. After removal of duplicates, abstract screening and full-text reviewing, 56 molecular and/or clinical studies were analyzed, including a novel FGB missense mutation in a woman with a mild bleeding phenotype. Results A total of 32 single causative mutations were reported, mainly in the COOH-terminal region of the γ or Aα chains at heterozygous or homozygous state. Seven additional hypodysfibrinogenemias were due to compound heterozygosity. The hypofibrinogenemic phenotypes were a result of an impaired assembly or secretion or an increased clearance of the fibrinogen variant, whereas the dysfibrinogenemic phenotype was mainly a result of a defective fibrin polymerization and an abnormal calcium or tPA binding. Among 51 identified index cases, a functional/antigenic fibrinogen ratio < 0.7 had a sensitivity of 86% for the diagnosis of hypodysfibrinogenemia. Eleven patients (22%) were asymptomatic at time of diagnosis, 23 (45%) had a mild bleeding phenotype with mainly obstetrical or gynecologic-related hemorrhage and 22 (43%) had experienced at least one thrombotic event, including 23 venous and eight arterial thromboses. Conclusions This first systematic review on hypodysfibrinogenemia shows the heterogeneity of causative mutations and that misdiagnosis could occur in relation to the functional and antigenic fibrinogen levels. Family studies reveal an incomplete segregation of the mutation with the clinical phenotype.

The effects of human plasma protein solution 5% on blood coagulation and chemistry, an experimental in-vitro study

Objective: The effect of different fluids used for resuscitation was studied in the literature in vitro and the results were different and not consistent. This study aims to study the in-vitro effect on coagulation of a newly used Human Plasma Protein (PP) solution 5% solution as a primary end point and its effect on blood SID and PH as secondary end points. Methods: In an experimental in-vitro study, different dilutions 10, 30 and 50% of PP 5% solution and fresh blood samples collected from volunteers, in which one cc of PP 5% is mixed to 9 cc of blood (10% dilution), 3 cc of PP 5% to 7 cc of Blood (30% dilution), and 2.5 cc of PP 5% to 2.5 cc of blood (50% dilution). Blood samples were analyzed for slandered Thrombo-Elastogram (TEG) and functional Fibrinogen level. TEG measurements included: r time, K time, α angle, ma (Maximum Amplitude), CI (Coagulation index), and LY 30 (lysis after 30 min of MA). Results: Reference figure below. Conclusion: The changes in coagulation induced by 30 and 50% dilution were significant. Changes in fibrinogen with extreme dilution of 50% do not indicate fibrinogen transfusion and haemoglobin level stay within the acceptable range and below transfusion trigger for healthy patients.

Impact of high dose vitamin C on platelet function.

AIMTo examine the effect of high doses of vitamin C (VitC) on ex vivo human platelets (PLTs).METHODSPlatelet concentrates collected for therapeutic or prophylactic transfusions were exposed to: (1) normal saline (control); (2) 0.3 mmol/L VitC (Lo VitC); or (3) 3 mmol/L VitC (Hi VitC, final concentrations) and stored appropriately. The VitC additive was preservative-free buffered ascorbic acid in water, pH 5.5 to 7.0, adjusted with sodium bicarbonate and sodium hydroxide. The doses of VitC used here correspond to plasma VitC levels reported in recently completed clinical trials. Prior to supplementation, a baseline sample was collected for analysis. PLTs were sampled again on days 2, 5 and 8 and assayed for changes in PLT function by: Thromboelastography (TEG), for changes in viscoelastic properties; aggregometry, for PLT aggregation and adenosine triphosphate (ATP) secretion in response to collagen or adenosine diphosphate (ADP); and flow cytometry, for changes in expression of CD-31, CD41a, CD62p and CD63. In addition, PLT intracellular VitC content was measured using a fluorimetric assay for ascorbic acid and PLT poor plasma was used for plasma coagulation tests [prothrombin time (PT), partial thrombplastin time (PTT), functional fibrinogen] and Lipidomics analysis (UPLC ESI-MS/MS).RESULTSVitC supplementation significantly increased PLTs intracellular ascorbic acid levels from 1.2 mmol/L at baseline to 3.2 mmol/L (Lo VitC) and 15.7 mmol/L (Hi VitC, P < 0.05). VitC supplementation did not significantly change PT and PTT values, or functional fibrinogen levels over the 8 d exposure period (P > 0.05). PLT function assayed by TEG, aggregometry and flow cytometry was not significantly altered by Lo or Hi VitC for up to 5 d. However, PLTs exposed to 3 mmol/L VitC for 8 d demonstrated significantly increased R and K times by TEG and a decrease in the α-angle (P < 0.05). There was also a fall of 20 mm in maximum amplitude associated with the Hi VitC compared to both baseline and day 8 saline controls. Platelet aggregation studies, showed uniform declines in collagen and ADP-induced platelet aggregations over the 8-d study period in all three groups (P > 0.05). Collagen and ADP-induced ATP secretion was also not different between the three groups (P > 0.05). Finally, VitC at the higher dose (3 mmol/L) also induced the release of several eicosanoids including thromboxane B2 and prostaglandin E2, as well as products of arachidonic acid metabolism via the lipoxygenases pathway such as 11-/12-/15-hydroxyicosatetraenoic acid (P < 0.05).CONCLUSIONAlterations in PLT function by exposure to 3 mmol/L VitC for 8 d suggest that caution should be exerted with prolonged use of intravenous high dose VitC.