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Capillary blood samples are generally assumed as unsuitable for coagulation testing since it is recognized that contamination with tissue factor and dilution with tissue fluid affects the coagulation assay. However, limited data is available about coagulations assays in which capillary blood sampling is compared to the standard venous blood withdrawal method. The aim of this study was to perform a method comparison between capillary and venous blood sampling for routine coagulation assays.Both venous and capillary (finger stick) blood samples were collected from 188 healthy volunteers and patients. In citrate plasma, International Normalized Ratio (INR), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, and D-dimer were measured according to routine protocols using the ACL-TOP 750 LAS (Werfen) coagulation analyzer. Regression analysis was performed and the mean relative difference between capillary and venous sampling was reflected to the total allowable error (TEa).Strong correlations and acceptable variations, using the TEa as decision limit, were found for INR, PT, TT, fibrinogen, and D-dimer between capillary and venous sampling. However, capillary sampling resulted in significant shorter APTT values when using the standard APTT-SP Liquid reagent with a mean bias of -10.4% [95% CI -12.4 to -8.4].Based on these results, capillary blood sampling proved to be an alternative blood withdrawal method for routine coagulation assays, with the exception of APTT, if a venipuncture is unavailable or undesired.

Factor X deficiency ranks among the rarest coagulopathies and has a variable presentation spectrum. We intend to present a proposal for anesthesia protocol for individuals with the coagulopathy. The excision of an ovarian neoplasm was proposed for a 26-year-old, female, ASA II patient, with congenital Factor X deficiency. Physical examination and lab tests were normal, except for Prothrombin Time (PT) 22.1s (VR: 8-14s), International Normalized Ratio (INR) 1.99 (VR: 0.8-1.2) and Activated Partial Thromboplastin Time (aPTT) 41.4s (VR: 25-37s). We concluded that a history of bleeding should always be investigated, along with a pre-anesthetic coagulation study.

Background Fermentation may alter the bioavailability of certain compounds, which may affect their efficacy and pharmacological responses. This study investigated the antiplatelet effects of red ginseng extract (RGE) and fermented red ginseng extract (FRG). Methods A rodent model was used to evaluate the antiplatelet and antithrombotic effects of the extracts. Rats were orally fed with human equivalent doses of the extracts for 1 week and examined for various signaling pathways using standard in vivo and ex vivo techniques. Light transmission aggregometry was performed, and calcium mobilization, dense granule secretion, integrin αIIbβ3-mediated signaling molecules, cyclic nucleotide signaling events, and various protein molecules were evaluated ex vivo in collagen-stimulated washed platelets. Furthermore, antithrombotic properties were evaluated using a standard acute pulmonary thromboembolism model, and the effects on hemostasis were investigated using rat and mice models. Results Both RGE and FRG significantly inhibited platelet aggregation, calcium mobilization, and dense granule secretion along with integrin-mediated fibrinogen binding and fibrinogen adhesion. cAMP levels were found to be elevated in RGE-treated rat platelets. Ginseng extracts did not exert any effect on prothrombin time and activated partial thromboplastin time. RGE-treated mice showed significantly better survival under thrombosis than FRG-treated mice, with no effects on hemostasis, whereas FRG-treated mice exhibited a slight increment in bleeding time. Conclusion Both extracts, especially RGE, are remarkable supplements to maintain cardiovascular health and are potential candidates for the treatment and prevention of platelet-related cardiovascular disorders.

BACKGROUND: Pulmonary vascular microthrombi are a proposed mechanism of COVID-19 respiratory failure. We hypothesized that early administration of tissue plasminogen activator (tPA) followed by therapeutic heparin would improve pulmonary function in these patients. RESEARCH QUESTION: Does tPA improve pulmonary function in severe COVID-19 respiratory failure, and is it safe? STUDY DESIGN AND METHODS: Adults with COVID-19-induced respiratory failure were randomized from May14, 2020 through March 3, 2021, in two phases. Phase 1 (n = 36) comprised a control group (standard-of-care treatment) vs a tPA bolus (50-mg tPA IV bolus followed by 7 days of heparin; goal activated partial thromboplastin time [aPTT], 60-80 s) group. Phase 2 (n = 14) comprised a control group vs a tPA drip (50-mg tPA IV bolus, followed by tPA drip 2 mg/h plus heparin 500 units/h over 24 h, then heparin to maintain aPTT of 60-80 s for 7 days) group. Patients were excluded from enrollment if they had not undergone a neurologic examination or cross-sectional brain imaging within the previous 4.5 h to rule out stroke and potential for hemorrhagic conversion. The primary outcome was Pao2 to Fio2 ratio improvement from baseline at 48 h after randomization. Secondary outcomes included Pao2 to Fio2 ratio improvement of > 50% or Pao2 to Fio2 ratio of ≥ 200 at 48 h (composite outcome), ventilator-free days (VFD), and mortality. RESULTS: Fifty patients were randomized: 17 in the control group and 19 in the tPA bolus group in phase 1 and eight in the control group and six in the tPA drip group in phase 2. No severe bleeding events occurred. In the tPA bolus group, the Pao2 to Fio2 ratio was significantly (P < .017) higher than baseline at 6 through 168 h after randomization; the control group showed no significant improvements. Among patients receiving a tPA bolus, the Pao2 to Fio2 ratio at 48 h (16.9% [interquartile range (IQR), -8.3% to 36.8%] vs 29.8% [IQR, 4.5%-88.7%]; P = .11), the composite outcome (11.8% vs 47.4%; P = .03), VFD (0.0 [IQR, 0.0-9.0] vs 12.0 [IQR, 0.0-19.0]; P = .11), and in-hospital mortality (41.2% vs 21.1%; P = .19) did not reach statistically significant differences when compared with those of control participants. The patients who received a tPA drip did not experience benefit. INTERPRETATION: The combination of tPA bolus plus heparin is safe in severe COVID-19 respiratory failure. A phase 3 study is warranted given the improvements in oxygenation and promising observations in VFD and mortality. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT04357730; URL: www.clinicaltrials.gov.

Background and Aims Standard coagulation tests such as prothrombin time, activated partial thromboplastin time, and international normalized ratio are determined by liver-synthesized coagulation factors. Despite an increased international normalized ratio, patients with cirrhosis are in a “rebalanced” state of hemostasis as the concomitant effect of reduced protein C, protein S, and thrombomodulin is not evaluated in standard coagulation tests. The cell-based model of hemostasis indicates additional mechanisms such as systemic inflammation, sepsis, and organ failures tip the delicate coagulation balance to an anticoagulant type in acute-on-chronic liver failure. In acute liver failure, thrombin generation and platelet function remain intact despite a marked prolongation in prothrombin time. We aimed to explain the principles, application, and utility of viscoelastic tests such as thromboelastography, rotational thromboelastometry, and Sonoclot. Methods We reviewed the available literature from MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trial with the search terms 'coagulation', 'cirrhosis', 'acute-on-chronic liver failure', 'thromboelastography', 'thromboelastometry' and 'sonoclot' for cross sectional studies, cohort studies and randomized trials Results The point-of-care viscoelastic tests provide actionable targets for correcting the coagulation defect in a patient with bleeding and provide evidence-based algorithms for use in liver disease. A limitation of these tests is the inability to assess vessel injury and endothelial elements. Conclusion Global coagulation tests provide a comprehensive estimate of coagulation in vitro; however, their use has only been validated in the setting of liver transplantation. Newer guidelines for hemostatic resuscitation are now accepting these POC tests, but additional data are required to validate their use as standard of care.

BACKGROUND Milvexian (BMS-986177/JNJ-70033093) is an orally bioavailable factor XIa (FXIa) inhibitor currently in phase 2 clinical trials. OBJECTIVES To evaluate in vitro properties and in vivo characteristics of milvexian. METHODS In vitro properties of milvexian were evaluated with coagulation and enzyme assays, and in vivo profiles were characterized with rabbit models of electrolytic-induced carotid arterial thrombosis and cuticle bleeding time (BT). RESULTS Milvexian is an active-site, reversible inhibitor of human and rabbit FXIa (Ki 0.11 and 0.38 nM, respectively). Milvexian increased activated partial thromboplastin time (APTT) without changing prothrombin time and potently prolonged plasma APTT in humans and rabbits. Milvexian did not alter platelet aggregation to ADP, arachidonic acid, or collagen. Milvexian was evaluated for in vivo prevention and treatment of thrombosis. For prevention, milvexian 0.063 + 0.04, 0.25 + 0.17, and 1 + 0.67 mg/kg+mg/kg/h preserved 32 ± 6*, 54 ± 10*, and 76 ± 5%* of carotid blood flow (CBF) and reduced thrombus weight by 15 ± 10*, 45 ± 2*, and 70 ± 4%*, respectively (*p

Background Factor XI (FXI) inhibition offers the promise of hemostasis-sparing anticoagulation for the prevention and treatment of thromboembolic events. Abelacimab (MAA868) is a novel fully human monoclonal antibody that targets the catalytic domain and has dual activity against the inactive zymogen Factor XI and the activated FXI. Objectives To investigate the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of single dose intravenous and multiple dose subcutaneous administration of abelacimab in healthy volunteers and patients with atrial fibrillation, respectively. Patients/methods In study ANT-003, healthy volunteers were administered single intravenous doses of abelacimab (30 to 150 mg) or placebo. The ANT-003 study also included a cohort of obese but otherwise healthy subjects. In study ANT-004, patients with atrial fibrillation were administered monthly subcutaneous doses of abelacimab (120 mg and 180 mg), or placebo, for 3 months. Key PK and PD parameters, including activated partial thromboplastin time (aPTT) and free FXI levels, as well as anti-drug antibodies (ADA) were assessed. Results Following intravenous administration of abelacimab, the terminal elimination half-life ranged from 25 to 30 days. One hour after the start of the intravenous infusion greater than 99% reductions in free FXI levels were observed. Following once monthly subcutaneous administration, marked reductions from baseline in free FXI levels were sustained. Parenteral administration of abelacimab demonstrated a favorable safety profile with no clinically relevant bleeding events. Conclusions Intravenous and multiple subcutaneous dose administration of abelacimab were safe and well tolerated. The safety, PK, and PD data from these studies support the clinical development of abelacimab.

Objectives : The COVID-19 pandemic has been associated with cases of refractory acute respiratory distress syndrome (ARDS) sometimes requiring support with extracorporeal membrane oxygenation (ECMO). Bivalirudin can be used for anticoagulation in patients on ECMO support, but its efficacy and safety in patients with COVID-19 is unknown. We set out to compare the pharmacologic characteristics and dosing requirements of bivalirudin in patients requiring ECMO support for ARDS due to COVID-19 versus ARDS from other etiologies. Design and Setting : This retrospective case control study was performed at Indiana University Health Methodist Hospital in Indianapolis, IN. Participants : Patients were included if they were on veno-venous (VV) ECMO support between June 2019 and June 2020 and divided into two groups: ARDS secondary to COVID-19 and those with ARDS from another etiology (Non-COVID). Interventions : Patient demographics such as age, sex, weight, chronic comorbid conditions, baseline antiplatelet and anticoagulant use, antiplatelet use during ECMO, and need for renal replacement therapy were collected and compared between groups. Time to activated partial thromboplastin time (aPTT) goal, percentage of time at aPTT goal, bivalirudin rates, total bivalirudin requirements, total duration on bivalirudin, total duration on ECMO, mortality, and complications associated with ECMO were collected and compared between groups. Measurements and Main Results : A total of forty-two patients met inclusion criteria (n = 19 COVID-19, n = 23 Non-COVID). However, percentage of aPTTs at goal were maintained more consistently in patients with COVID-19 versus non-COVID (86% vs. 74%: p < 0.01). Higher median (IQR) daily rates (3.1 mCg/kg/min (2.3-5.2) vs. 2.4 mCg/kg/min (1.7-3.3): p = 0.05) and higher median (IQR) maximum rates of bivalirudin (5 mCg/kg/min (3.7-7.5) vs. 3.8 mCg/kg/min (2.5-5): p = 0.03) were required in the COVID-19 group versus the non-COVID group. Time to goal aPTT was similar between groups. There was no difference in complications associated with anticoagulation as demonstrated by similar rates of bleeding and thrombosis between both groups. Conclusions : Patients on ECMO with ARDS from COVID-19 require more bivalirudin overall and higher rates of bivalirudin to maintain goal aPTTs compared to patients without COVID-19. However, COVID-19 patients more consistently maintain goal aPTT. Future randomized trials are needed to support efficacy and safety of bivalirudin for anticoagulation of COVID-19 patients on ECMO.

Pulmonary endarterectomy (PEA) is the main treatment for chronic thromboembolic pulmonary hypertension (CTEPH). Postoperative unfractionated heparin dosing can be monitored by activated partial thromboplastin time (APTT) or by anti-factor Xa activity (anti-Xa). In pseudo heparin resistance, APTT response to heparin is blunted due to elevated Factor VIII (FVIII) which can underestimate anticoagulation. We examined possible pseudo heparin resistance after PEA and assessed the impact of FVIII. APTT response to heparin before and after operation was determined in 13 PEA patients anticoagulated with unfractionated heparin. APTT and anti-Xa concordance was analyzed from paired postoperative samples, and antithrombin, fibrinogen and FVIII levels were measured. Single-cell RNA sequencing was used to characterize FVIII gene expression in PEA specimens of 5 patients. APTT response to heparin was blunted after PEA. APTT and anti-Xa were discordant in 36% of postoperative samples and most common discordant patterns were subtherapeutic APTT with therapeutic (16%) or supratherapeutic (11%) anti-Xa. Overall, APTT underestimated anticoagulation relative to anti-Xa in one-third of the samples. FVIII levels were elevated before surgery, increased substantially 1 and 3 days (median 4.32 IU/mL) after PEA, and were higher in discordant than concordant samples. Single-cell RNA sequencing showed FVIII gene expression in PEA specimen endothelial cells. Pseudo heparin resistance is common after PEA likely due to highly elevated postoperative FVIII levels indicating that anti-Xa reflects postoperative heparinization better than APTT in these patients. FVIII production by the pulmonary artery endothelium may participate in local prothrombotic processes important for CTEPH pathogenesis.

Background Anticoagulation therapy management during venoarterial extracorporeal membrane oxygenation (ECMO) is particularly difficult in postcardiotomy shock patients given a significant bleeding risk. We sought to determine the effect of anticoagulation treatment on bleeding and thrombosis risk for postcardiotomy shock patients on ECMO. Methods We retrospectively reviewed patients who received ECMO for postcardiotomy shock from July 2007 through July 2019. Characteristics of patients who had bleeding and thrombosis were investigated, and risk factors were assessed by multilevel logistic regression. Results Of the 152 patients who received ECMO for postcardiotomy shock, 33 (23%) had 40 thrombotic events and 64 (45%) had 86 bleeding events. Predictors of bleeding were intraoperative packed red blood cell transfusion (odds ratio [OR] 1.05; 95% confidence interval [CI], 1.01 to 1.09), platelet transfusion (OR 1.10; 95% CI, 1.05 to 1.16), international normalized ratio (OR 1.18; 95% CI, 1.02 to 1.37), and activated partial thromboplastin time greater than 60 seconds (OR 2.32; 95% CI, 1.14 to 4.73). Predictors of thrombosis were anticoagulant use (OR 0.39; 95% CI, 0.19 to 0.79), surgical venting (OR 3.07; 95% CI, 1.29 to 7.31), hemoglobin (OR 1.38; 95% CI, 1.06 to 1.79), and central cannulation (OR 2.06; 95% CI, 1.03 to 4.11). The daily predicted probability of thrombosis was between 0.075 and 0.038 for patients who did not receive anticoagulation and decreased to between 0.030 and 0.013 for patients who received anticoagulation treatment at activated partial thromboplastin times between 25 and 80 seconds. Conclusions Anticoagulation therapy can reduce thromboembolic events in postcardiotomy shock patients on ECMO, but bleeding risk may outweigh this benefit at activated partial thromboplastin times greater than 60 seconds.

Background: Coronavirus disease 2019 (COVID-19) pandemic continues to escalate intensively worldwide. Massive studies on general populations with SARS-CoV-2 infection have revealed that pre-existing comorbidities were a major risk factor for the poor prognosis of COVID-19. Notably, 49–75% of COVID-19 patients had no comorbidities, but this cohort would also progress to severe COVID-19 or even death. However, risk factors contributing to disease progression and death in patients without chronic comorbidities are largely unknown; thus, specific clinical interventions for those patients are challenging. Methods: A multicenter, retrospective study based on 4806 COVID-19 patients without chronic comorbidities was performed to identify potential risk factors contributing to COVID-19 progression and death using LASSO and a stepwise logistic regression model. Results: Among 4806 patients without pre-existing comorbidities, the proportions with severe progression and mortality were 34.29% and 2.10%, respectively. The median age was 47.00 years [interquartile range, 36.00–56.00], and 2162 (44.99%) were men. Among 51 clinical parameters on admission, age ≥ 47, oxygen saturation < 95%, increased lactate dehydrogenase, neutrophil count, direct bilirubin, creatine phosphokinase, blood urea nitrogen levels, dyspnea, increased blood glucose and prothrombin time levels were associated with COVID-19 mortality in the entire cohort. Of the 3647 patients diagnosed with non-severe COVID-19 on admission, 489(13.41%) progressed to severe disease. The risk factors associated with COVID-19 progression from non-severe to severe illness were increased procalcitonin levels, SpO2 < 95%, age ≥ 47, increased LDH, activated partial thromboplastin time levels, decreased high-density lipoprotein cholesterol levels, dyspnea and increased D-dimer levels. Conclusions: COVID-19 patients without pre-existing chronic comorbidities have specific traits and disease patterns. COVID-19 accompanied by severe bacterial infections, as indicated by increased procalcitonin levels, was highly associated with disease progression from non-severe to severe. Aging, impaired respiratory function, coagulation dysfunction, tissue injury, and lipid metabolism dysregulation were also associated with disease progression. Once factors for multi-organ damage were elevated and glucose increased at admission, these findings indicated a higher risk for mortality. This study provides information that helps to predict COVID-19 prognosis specifically in patients without chronic comorbidities.

Background This study evaluated E-selectin inhibition with GMI-1271 (Uproleselan [GMI]) alone and in combination with the standard of care low-molecular-weight heparin (LMWH) to improve vein recanalization, decrease vein wall inflammation and protect against adverse bleeding in a primate model. We sought to examine this novel treatment of venous thrombosis. Methods Using a well-documented primate animal model, iliac vein thrombosis was induced by balloon occlusion of the iliac vein for 6 hours. Starting on day 2 after thrombosis, animals began treatment in two phases. In phase one, nontreated controls received no treatment (n = 5) vs animals treated with the E-selectin inhibitor GMI, 25 mg/kg, subcutaneous (SC), once daily (n = 4) for 21 days (previously published data). In phase two, animals were treated with GMI plus a combination of LMWH 1.5 mg/kg or 40 mg (GMI + LMWHc) SC once daily (n = 8) for 19 days; and animals treated with LMWH 1.5 mg/kg or 40 mg (LMWHc) SC once daily (n = 6) for 19 days. Animals were evaluated by magnetic resonance venography for vein recanalization and inflammation by gadolinium extravasation, duplex ultrasound, coagulation tests (thromboelastography, bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen) and complete blood count at baseline, days 2, 7, 14, and 21 at euthanasia. Statistical analysis included using unpaired t test with Welch's correction for direct comparisons and one-way analysis of variance for comparison between the groups. Results Percent vein recanalization by magnetic resonance venography was highest in the GMI alone group followed by GMI + LMWHc, both significantly different from control. On ultrasound examination, animals treated with GMI alone had no decrease in open vein lumen by day 21, whereas decreases were observed in groups GMI + LMWHc (–26%), LMWHc (–27%), and controls (–80%). Vein wall inflammation decreased significantly in all treated groups. Intimal fibrosis and intimal thickness was best preserved in the GMI alone group. An analysis of total vein wall collagen revealed a trend in all treatment groups of decreasing vein wall collagen. No clinically significant bleeding events were noted in any group. The LMWH groups trended to have prolonged coagulation test values, whereas E-selectin inhibition with GMI did not cause clinically significant changes in coagulation measures. Conclusions Treatment with E-selectin inhibition results in improved vein recanalization, a decrease in vein wall inflammation and vein wall intimal thickness and fibrosis, with no changes in markers of coagulation. E-selectin inhibition with GMI alone is superior to E-selectin inhibition combined with LMWH, LMWH alone, and no treatment in this deep vein thrombosis model of iliac vein thrombosis.

Purpose The study objective was to explore whether prophylaxis with vitamin K1 improves abnormal coagulation function–associated cefoperazone-sulbactam in patients treated in the long term with low-dose aspirin. Methods This retrospective, observational study assessed patients treated with long-term low-dose aspirin in a naval military hospital in China from 2004 to 2018, including all patients treated concurrently with cefoperazone-sulbactam with or without vitamin K1. Differences in the coagulation index were analyzed statistically before and after receipt of cefoperazone-sulbactam. Findings The cohort included 227 patients. After cefoperazone-sulbactam treatment, the mean (SD) prothrombin time (PT) was 14.07 (3.07) seconds, activated partial thromboplastin time (aPTT) was 35.15 (4.78) seconds, and international normalized ratio (INR) was 1.49 (0.49) in the cefoperazone-sulbactam group, which was significantly higher than the PT of 11.55 (1.29), aPTT of 31.37 (2.20), and INR of 1.12 (0.35) before cefoperazone-sulbactam treatment. No significant difference was in the cefoperazone-sulbactam plus vitamin K1 group. In addition, no significant difference was found in the thrombin time or fibrinogen level between before and after cefoperazone-sulbactam treatment in both groups. The mean (SD) platelet counts of the 2 groups were 197.34 (71.82) × 109/L and 187.75 (72.66) × 1 09/L after cefoperazone-sulbactam treatment, respectively, which was significantly lower than 231.77 (77.05) × 109/L and 232.08 (84.48) × 109/L before cefoperazone-sulbactam treatment. There were greater proportions of coagulation disorders (prolongation of PT, aPTT, INR, and bleeding) after cefoperazone-sulbactam treatment in the cefoperazone-sulbactam group compared with that in the cefoperazone-sulbactam plus vitamin K1 group. Implications Results indicate that, after adding cefoperazone-sulbactam to the regimens of patients receiving long-term low-dose aspirin, therapy contributed to remarkable increase in abnormal coagulation function and coagulation disorders. Prophylaxis with vitamin K1 decreased the risk of these abnormalities in blood coagulation parameters associated with cefoperazone-sulbactam in patients taking long-term aspirin.

Introduction Continuous intravenous unfractionated heparin (UFH) is a mainstay of therapeutic anticoagulation in the acute setting. The two most common laboratory tests for monitoring UFH are the activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) heparin assay. We reviewed the available evidence to evaluate if the choice of monitoring test for UFH therapy is associated with a difference in the clinical outcomes of bleeding, thrombosis, or mortality. Materials and methods MEDLINE, Cochrane database, and conference abstracts from the Society of Critical Care Medicine, the American Society of Hematology, and the American College of Clinical Pharmacy were searched for all studies comparing aPTT and anti-Xa monitoring for therapeutic UFH that evaluated outcomes for bleeding, thrombotic events, or mortality. Risk of bias was assessed with the Cochrane Risk of Bias Tool and Newcastle Ottawa Scale. Pooled relative risk ratios were calculated using an inverse variance-weighted random-effects model. Results Ten studies (n = 6677) were included for analysis. The use of anti-Xa compared to aPTT was not associated with an increased risk of bleeding (RR 1.03; 95% CI 0.8–1.22 I2 = 4%) or an increased risk of thrombotic events (RR 0.99; 95% CI 0.76–1.30, I2 = 3%). There was no difference in mortality within individual studies but the data were not suitable for pooled analysis. Conclusions Pooled data comparing aPTT vs. anti-Xa for monitoring therapeutic UFH did not suggest differences in the outcomes of bleeding or thrombosis.

Background Effective inhibition of thrombosis without generating bleeding risks is a major challenge in medicine. Accumulating evidence suggests that this can be achieved by inhibition of coagulation factor XII (FXII), as either its knock-out or inhibition in animal models efficiently reduced thrombosis without affecting normal hemostasis. Based on these findings, highly specific inhibitors for human FXII(a) are under development. However, currently, in vivo studies on their efficacy and safety are impeded by the lack of an optimized animal model expressing the specific target, that is, human FXII. Objective The primary objective of this study is to develop and functionally characterize a humanized FXII mouse model. Methods A humanized FXII mouse model was generated by replacing the murine with the human F12 gene (genetic knock-in) and tested it in in vitro coagulation assays and in in vivo thrombosis models. Results These hF12\(^{KI}\) mice were indistinguishable from wild-type mice in all tested assays of coagulation and platelet function in vitro and in vivo, except for reduced expression levels of hFXII compared to human plasma. Targeting FXII by the anti-human FXIIa antibody 3F7 increased activated partial thromboplastin time dose-dependently and protected hF12\(^{KI}\) mice in an arterial thrombosis model without affecting bleeding times. Conclusion These data establish the newly generated hF12\(^{KI}\) mouse as a powerful and unique model system for in vivo studies on anti-FXII(a) biologics, supporting the development of efficient and safe human FXII(a) inhibitors.

BACKGROUND Liver cirrhosis is associated with immune deficiency, which causes these patients to be susceptible to various infections, including cryptococcus infection. Mortality in cirrhotic patients with cryptococcosis has increased. The present study was to explore the risk factors of mortality and the predictive ability of different prognostic models. METHODS Forty-seven cirrhotic patients with cryptococcosis at a tertiary care hospital were included in this retrospective study. Data on demographics, clinical parameters, laboratory exams, diagnostic methods, medication during hospitalization, severity scores and prognosis were collected and analyzed. Student's t test and Mann-Whitney test were used to compare characteristics of survivors and non-survivors at a 90-day follow-up and cerebrospinal fluid (CSF) manifestations of cryptococcal meningitis. Multivariate Cox regression analysis was used to identify the independent risk factors for mortality. Kaplan-Meier curves were used to analyze patient survival. Receiver operating characteristic (ROC) curves were used to evaluate the different prognostic factors. RESULTS The 30- and 90-day survival rates were 93.6% and 80.9%, respectively, in cirrhotic patients with cryptococcosis. Cryptogenic liver diseases [hazard ratio (HR) = 7.567, 95% confidence interval (CI): 1.616-35.428, P = 0.010], activated partial thromboplastin time (APTT) (HR = 1.117, 95% CI: 1.016-1.229, P = 0.022) and Child-Pugh score (HR = 2.146, 95% CI: 1.314-3.504, P = 0.002) were risk factors for 90-day mortality in cirrhotic patients with cryptococcosis. Platelet count (HR = 0.965, 95% CI: 0.940-0.991, P = 0.008) was a protective factor. APTT (HR = 1.120, 95% CI: 1.044-1.202, P = 0.002) and Child-Pugh score (HR = 1.637, 95% CI: 1.086-2.469, P = 0.019) were risk factors for 90-day mortality in cirrhotic patients with cryptococcal meningitis. There was significant difference in the percentage of lymphocytes in CSF between survivors and non-survivors [60.0 (35.0-75.0) vs. 95.0 (83.8-97.2), P < 0.001]. The model of end-stage liver disease-sodium (MELD-Na) score was more accurate for predicting 30-day mortality both in patients with cryptococcosis [area under curve (AUC): 0.826, 95% CI: 0.618-1.000] and those with cryptococcal meningitis (AUC: 0.742, 95% CI: 0.560-0.924); Child-Pugh score was more useful for predicting 90-day mortality in patients with cryptococcosis (AUC: 0.823, 95% CI: 0.646-1.000) and those with cryptococcal meningitis (AUC: 0.815, 95% CI: 0.670-0.960). CONCLUSIONS These results showed that cryptogenic liver diseases, APTT and Child-Pugh score were associated with mortality in cirrhotic patients with cryptococcosis and cryptococcal meningitis. MELD-Na score was important for predicting 30-day mortality, and Child-Pugh score was critical for predicting 90-day mortality.

Background Coagulation factor XI (FXI) contributes to the development of thrombosis but appears to play a minor role in hemostasis and is, therefore, an attractive anticoagulant drug target. Objectives To evaluate the safety, pharmacokinetic and pharmacodynamic properties of BAY 2433334, an orally administered small molecule targeting activated FXI (FXIa), in healthy men. Patients/methods This phase 1 study was conducted in two parts. In part 1, 70 volunteers were randomized 4:1 to receive a single oral dose of BAY 2433334 (5-150 mg as oral solution or immediate-release tablets) or placebo. In part 2, 16 volunteers received a single oral dose of five BAY 2433334 5 mg tablets with or without a high-calorie breakfast in a randomized crossover study design. Adverse events, pharmacokinetic parameters and pharmacodynamic parameters were assessed up to 72 hours after drug administration. Volunteers were followed up after 7-14 days. Results BAY 2433334 demonstrated favorable safety and tolerability with a dose-dependent increase in exposure and a terminal half-life of 14.2-17.4 hours. A high-calorie breakfast reduced mean maximum plasma concentration and exposure by 31% and 12.4%, respectively. BAY 2433334 was associated with a dose-dependent inhibition of FXIa activity and an increase in activated partial thromboplastin time. Bleeding times in volunteers who had received BAY 2433334 were similar to those in volunteers who had received placebo. Conclusions These data indicate that BAY 2433334 is a promising development candidate for once-daily oral anticoagulation; it is being evaluated in phase 2 dose-finding studies in patients at risk of thrombosis.

BACKGROUND Coagulation factor IX (FIX) is a serine protease zymogen involved in the intrinsic blood coagulation pathway, and its deficiency causes hemophilia B. Zebrafish has three f9 genes, and the ortholog to human F9 is unknown. OBJECTIVE To identify the zebrafish ortholog to F9 using sequence analysis and piggyback knockdown technology. METHODS Gene and protein sequence analysis for three f9 genes, f9a, f9b, and f9l, present in the zebrafish genome was performed. In vivo and in vitro assays after knockdown of each gene and immunodepletion using specific antibodies were carried out. RESULTS Sequence analysis revealed that f9a and f9b are similar to human F9, whereas f9l is similar to human F10. RNA analysis showed an age-dependent increase in expression of all three genes. Zebrafish f9a gene knockdown and Fixa immunodepletion prolonged kinetic partial thromboplastin time (kPTT), whereas f9l knockdown and Fixl immunodepletion prolonged kPTT, kinetic prothrombin time, and kinetic Russell viper venom activation time. Laser-assisted venous thrombosis increased time to occlusion after f9a and f9l knockdown and antibody inhibition of Fixa and Fixl. Further, analysis of plasma proteins by mass spectrometry and immunohistochemistry detected all three proteins. CONCLUSIONS Our findings suggest that zebrafish f9a has functional activity similar to human F9. Fixl is functionally similar to Fx. The age-dependent increases of these factors are comparable to those observed in mice and humans. Thus, the zebrafish model could be used to study factors involved in increasing f9a expression during aging. It could also be used to test whether normal human Factor IX and Factor IX Leyden promoter work in zebrafish background.

Introduction Combining an antiplatelet drug, clopidogrel, with the direct oral Factor Xa inhibitor, apixaban, could provide an effective antithrombotic strategy in dogs. Thus, a limited 3 + 3 phase I dose-escalation clinical trial in healthy dogs was conducted to evaluate bleeding (primary end-point) and pharmacodynamic (PD)/pharmacokinetic (PK) parameters (secondary end-point). Animals Eleven beagle dogs, median body weight 10.2 kg (9.7–10.9 kg), were enrolled. Methods Four doses of apixaban (three dogs/dose) administered for eight days. Clopidogrel dose was fixed at 18.75 mg per os (PO) q 24 h with escalation of apixaban dose at 5 mg PO q 12 h, 5 mg PO q 8 h, 10 mg PO q 12 h, and 10 mg PO q 8 h. Laboratory testing included fecal occult blood, coagulation parameters, Factor X activity, apixaban concentration, platelet aggregometry, and thromboelastography on days 1, 3, and 8. Results Evidence of bleeding was not observed at any dosage. Dose-dependent changes in PD/PK parameters between baseline and 3 h post-medication were observed including a prolongation of prothrombin time, a prolongation of activated partial thromboplastin time, a decrease of Factor X activity level, and increased apixaban concentration. Conclusions The combination of apixaban at a dosage range of approximately 0.5 mg/kg PO q 12 h to 1 mg/kg PO q 8 h and clopidogrel at approximately 1.8 mg/kg PO q 24 h did not cause bleeding over a one-week period in healthy dogs. Clinically relevant changes in PD/PK data occur at all dosage levels. This study provides a starting point for longer-term clinical trials to determine safety and efficacy.

Introduction Bed bugs are hematophagous insects that can be problematic in some urban emergency departments. The objective was to determine if red blood cell (RBC) and coagulation indices of bed bug–infested emergency department (ED) patients differed from those of noninfested control patients. Methods A chart review from a single health system was performed for ED patients between February 1, 2011, and February 1, 2017. Bed bug–infested patients were matched to noninfested control patients on the basis of age, sex, and the presenting ED. Variables were analyzed with the t-test and Pearson χ2 test and were modeled with multivariable logistic regression. Results The study had 332 bed bug–infested patients and 4952 controls. Infested patients had lower hemoglobin (11.7 g/dL vs 12.8 g/dL), hematocrit (35.0% vs 37.9%), RBC counts (4.1 × 109/L vs 4.4 × 109/L), mean corpuscular volume (86.0 vs 87.5 fL/cell), and mean corpuscular hemoglobin concentrations (33.2 vs 33.7 g/dL) and higher RBC distribution width-coefficient of variation (RDW-CV) (15.2% vs 14.2%) than noninfested patients (all P ≤ .003). Infested patients were more likely to be anemic (59.5% vs 36.9%) and to have severe anemia (4.4% vs 0.7%) (P Conclusion Bed bug infestated patients in the ED are associated with anemia.

Summary Dabigatran is an orally administrated anticoagulant that directly inhibits thrombin. However, the drug can affect routine coagulation tests such as prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT), as well as haemostasis assays, (e.g., clot-based coagulation factor assays). There are limited data on the effect of dabigatran on some fibrinogen measurements and on D-dimer assays, both important components in the laboratory assessment of disseminated intravascular coagulation (DIC). The objectives of this study were: (1) to determine the effects of various concentrations of dabigatran on fibrinogen and D-Dimer assays; and (2) to compare the von Clauss method of fibrinogen measurement using two reagents with differing thrombin concentrations (35 UNIH/mL and 100 UNIH/mL) and PT-derived fibrinogen measurement in the presence of the drug. Aliquots of pooled normal plasma were spiked with different concentrations of dabigatran to reflect in vivo on-therapy levels as well as levels observed in cases of massive accumulation of the drug. Of the routine coagulation assays, in ascending order of sensitivity to dabigatran were PT, APTT and TT. The von Clauss method of measuring fibrinogen using a reagent with low thrombin concentration was affected even at drug levels corresponding to in vivo trough concentrations, whereas the reagent with higher thrombin concentration was only affected at drug levels that were above observed peak concentrations in patients taking 150 mg of the drug twice daily. PT-derived fibrinogen was affected at approximately in vivo peak drug concentrations. The D-dimer assay was affected only at drug concentrations well above peak drug levels. Attempts at in vitro neutralisation of the drug with DOAC-Stop resulted in ‘correction’ of some of these measurements depending on drug concentration. Like the routine coagulation assays, there is a dabigatran concentration dependent effect on the accuracy of fibrinogen and D-dimer assays. Falsely low fibrinogen results due to dabigatran may confound the assessment of DIC and diagnostic laboratories need to evaluate the performance of their own reagents.

Introduction Unfractionated heparin (UFH) therapy is monitored by using the anti-activated factor X (anti-Xa) activity, or the activated partial thromboplastin time (APTT), which remains the most widely used assay. One of the main advantages of anti-Xa relies on its hypothesized standardization, with a unique therapeutic range (0.30-0.70 IU/ml) for all reagents, whereas APTT is influenced by numerous preanalytical and analytical parameters not related to the anticoagulant activity of UFH. Methods The aim of this study was to compare the anti-Xa-correlated APTT therapeutic ranges calculated using different combinations of APTT (n = 4) and anti-Xa reagents (n = 4) in frozen citrated plasmas from 87 inpatients on UFH. Results The median APTT ratio ranged from 2.19 for the less sensitive to 3.23 for the most sensitive reagent, whereas the median anti-Xa activity was between 0.37 IU/ml and 0.57 IU/ml. The APTT therapeutic ranges calculated to correlate with anti-Xa activities between 0.30 and 0.70 IU/ml were found to be highly different from one combination of APTT reagent and analyzer to another. The same applied to the therapeutic range of a single APTT reagent calculated using different anti-Xa assays performed on the same analyzer, leading to a lack of agreement as to whether a sample was classified as subtherapeutic, therapeutic or supratherapeutic in 8.0% to 23.0% of the patients, with kappa coefficients between 0.908 and 0.753. Conclusions These results suggest that the APTT therapeutic range calculated to correlate with anti-Xa activities between 0.30 and 0.70 IU/ml is influenced not only by the APTT reagent, but also by the anti-Xa reagent used for calculation.

The present study evaluated the in vitro and in vivo potential toxicological effects, and the in vitro anticoagulant action of Licania rigida Benth crude leaf extract (CELR) and ethyl acetate fraction (AFLR). The in vitro toxicity was assessed by means of the MTT assay using mouse fibroblasts (3T3) and human embryonic kidney cells (HEK-293), while the acute oral toxicity test employed Wistar rats. No apparent toxicity was observed after exposure to the extracts. Regarding the anticoagulant capacity, the activated partial thromboplastin time (aPTT) and prothrombin time (PT) tests demonstrated the extracts’ anticoagulant potential at a concentration of 50 µg/mL. However, only AFLR inhibited 100% of the thrombin IIa factor at a concentration of 100 µg/mL, which corresponds to the extrinsic coagulation pathway in comparison to heparin (control). Although both CELR and AFLR exhibited anticoagulant and non-toxic effects, further studies are required to validate their phytotherapeutic applications.

Acquires hemophilia A (AHA) is rare bleeding condition commonly associated with malignancy, autoimmune disease, or pregnancy. We report a case of a 69‐year‐old gentleman who developed bleeding symptoms after receiving COVID‐19 vaccine. Laboratory testing showed isolated prolongation of the activated partial thromboplastin time, and normal von Willebrand factor. Further testing confirmed the presence of factor VIII inhibitor. To date, no cases of AHA have been reported after exposure to COVID‐19 vaccine. There have been two cases of AHA following seasonal flu and H1N1 vaccination, as well as two cases of AHA following COVID‐19 infection. We present a summary of these cases and review of literature of autoimmune reactions following vaccination.

Superwarfarins are second generation anticoagulants that work as highly potent vitamin K antagonist, used in many chemical poisons as rodenticide. Superwarfarins currently constitute variety of examples like Brodifacoum, Difenacoum, Bromadiolone, and Flocoumafen. With the increase usage of these compounds a lot of poisoning cases has been reported worldwide, most of these poisoning cases occur either by accidental exposure or suicidal attempts. Poisoning routes are inhalational, trans-cutaneous and oral routes. Most of the cases present clinically with skin bleeding, hematuria, epistaxis, digestive tract bleeding, and rarely intracranial bleeding. We report a 49-year-old man with a Bromadiolone poisoning that led to massive intracranial hemorrhage and treated for several months with vitamin K1 agonist. His first clinical presentation was altered level of consciousness, right sided Hemiplegia, left sided hemiparesis, headache, and recurrent vomiting, with history of gross hematuria, hematochezia, and epistaxis, which had been persistent over the last 10 days prior to his presentation. On physical examination Glasgow Coma Scale (GCS) was 14/15 (confused), cranial nerves were intact except flatten right nasolabial fold and mild mouth drop, deep Tendon reflexes were brisk reflexes (+3) all over, power showed right sided hemiplegia (0/5), and left sided hemiparesis (4/5). Prothrombin Time (PT), activated Partial Thromboplastin Time (aPTT), and the International Normalized Ratio (INR) was prolonged and high, respectively. In conclusion, Superwarfarin toxicity should be suspected in cases of unknown etiology of coagulopathy, with increased INR of more than six and increased coagulation profile time PT, and aPTT which is not responding to FFP treatment.

Background Limited information exists regarding the factor IX (FIX) coagulant activity (FIX:C) measured by different assays following FIX‐Padua gene therapy. Objective Assess for the first time FIX:C in five commonly used coagulation assays in plasma samples from hemophilia B subjects receiving FIX‐Padua gene transfer. Methods FIX:C was compared between central (n = 1) and local laboratories (n = 5) in the study, and across four commonly used FIX:C one‐stage assays and one FIX:C chromogenic assay. For comparison, samples of pooled congenital FIX‐deficient plasma spiked with purified recombinant human FIX (rHFIX)‐Padua protein or rHFIX (nonacog alfa) to obtain FIX:C concentrations from ~20% to ~40% were tested. Results FIX:C results at local laboratories strongly correlated with central laboratory results. However, absolute values at the central laboratory were consistently lower than those at local laboratories. Across five different FIX:C assays, a consistent pattern of FIX:C was observed for subjects receiving fidanacogene elaparvovec‐expressed gene transfer. Use of Actin FSL activated partial thromboplastin time (APTT) reagent in the central laboratory resulted in lower FIX:C values compared with other APTT reagents tested. The chromogenic assay determined lower FIX:C than any of the one‐stage assays. The rHFIX‐Padua protein–spiked samples showed similar results. In contrast, FIX:C results for rHFIX‐nonacog alfa measured within 25% of expected for all one‐stage assays and below 25% in the chromogenic assay. Conclusions Assay‐based differences in FIX:C were observed for fidanacogene elaparvovec transgene product and rHFIX‐Padua protein, suggesting the variable FIX:C determined with different assay reagents is inherent to the FIX‐Padua protein and is not specific to gene therapy–derived FIX‐Padua.

Summary Background There are no approved treatments for vaso-occlusive crises in sickle cell disease. Sevuparin is a novel non-anticoagulant low molecular weight heparinoid, with anti-adhesive properties. In this study, we tested whether sevuparin could shorten vaso-occlusive crisis duration in hospitalised patients with sickle cell disease. Methods We did a multicentre, double-blinded, placebo-controlled, phase 2 study in 16 public access clinical hospitals in the Netherlands, Lebanon, Turkey, Bahrain, Oman, Saudi Arabia, and Jamaica. Patients aged 12–50 years with a diagnosis of sickle cell disease (types HbSS, HbSC, HbSβ0-thalassaemia, or HbSβ+-thalassaemia) on a stable dose of hydroxyurea, hospitalised with vaso-occlusive crisis for parenteral opioid analgesia with a projected stay of more than 48 h were included in the study. Patients were randomly assigned (1:1) using a computer-generated randomisation scheme to receive sevuparin (18 mg/kg per day) or placebo (NaCl, 0·9% solution) intravenously for 2–7 days until vaso-occlusive crisis resolution. All individuals involved in the trial were masked to treatment allocation. The analysis was done in the intention-to-treat population. The primary endpoint was time to vaso-occlusive crisis resolution defined as freedom from parenteral opioid use (in preceding 6–10 h); and readiness for discharge as judged by the patient or physician. The trial is registered with ClinicalTrials.gov , NCT02515838 . Findings Between Oct 7, 2015, and Feb 10, 2019, 144 patients were randomly assigned and administered sevuparin (n=69) or placebo (n=75). The median age was 22·2 years (range 12·2–33·6), 104 (72%) 144 were adults (18 years or older), and 90 (63%) were male and 54 (37%) were female. The intention-to-treat analysis for the primary endpoint showed no significant difference in median time to vaso-occlusive crisis resolution between the sevuparin and placebo groups (100·4 h [95% CI 85·5–116·8]) vs 86·4 h [70·6–95·1]; hazard ratio 0·89 [0·6–1·3]; p=0·55). Serious adverse events occurred in 16 (22%) of 68 patients in the sevuparin group and in 21 (22%) of patients in the placebo group. The most frequent treatment-emergent adverse events were pyrexia (17 [25%] in the sevuparin group vs 17 [22%] in the placebo group), constipation (12 [18%] vs 17 [22%]), and decreased haemoglobin (18 [26%] vs 9 [12%]). There were no deaths in the sevuparin group and there was one (1%) death in the placebo group after a hyper-haemolytic episode due to alloimmunisation. Interpretation This result, as well as the results seen in other clinical studies of inhibitors of adhesion in sickle cell disease, suggest that selectin-mediated adhesion might be important in the initiation, but not maintenance of vaso-occlusion, indicating that strategies to treat vaso-occlusive crises differ from strategies to prevent this complication. Funding Modus Therapeutics.

This study aimed to isolate, characterize chemical-structurally and evaluate the effects of polysaccharides from Caesalpinia (Libidibia) ferrea stem barks in the haemostatic system. The deproteinated-polysaccharide extract (PE-Cf) after being fractionated by ion exchange chromatography-DEAE-cellulose resulted in three fractions (FI, FII, FIII) containing total carbohydrates (14.3–38%), including uronic acid (5–16%), and polyphenols (0.94–1.7 mg/g GAE). The polysaccharide fractions presented polydisperse profile in polyacrylamide gel electrophoresis (detected by Stains-All) and molecular masses (9.5 × 104 Da–1.5 × 105 Da) identified by gel permeation chromatography. FT-IR showed absorption bands (1630 cm−1, 1396–1331 cm−1), indicative of uronic acid, and a band at 1071 cm−1, typical of COO− groups of galacturonic acid. The NMR spectra of C. ferrea polysaccharides revealed a central core composed mainly by 5-linked α-Araf and minority components as α-Rhap and α-GalAp. UV spectra of fractions revealed discrete shoulders at 269–275 nm, characteristic of polyphenolic compounds. In vitro, polysaccharides inhibited the intrinsic and/or common coagulation pathway (aPTT test) (2.0–3.7 fold) and the platelet aggregation induced by 3 μM adenosine diphosphate (25–48%) and 5 μg/mL collagen (24%), but not that induced by arachidonic acid. In vivo, the polysaccharides inhibited (36–69%) venous thrombosis induced by hypercoagulability and stasis, showing discrete hemorrhagic effect. In conclusion, the polysaccharides of C. ferrea barks, containing arabinose, galactose, rhamnose and uronic acid, possess anticoagulant, antiplatelet and antithrombotic properties of low hemorrhagic risk, suggesting potential applicability in thromboembolic disorders.

A wide variety of animal models on thrombosis and hemostasis are used in thrombosis and hemostasis research for the preclinical assessment of hemostatic agents. While the vertebrate coagulome is highly conserved, human and animal plasmas differ considerably when evaluated in coagulation assays such as prothrombin time (PT), activated partial thromboplastin time (APTT), and calibrated automated thrombography (CAT). Here, we have aimed to provide a reference framework for the evaluation of coagulation assays and inhibition of activated human FXa (hFXa) in various animal plasmas. To do so, a side-by-side evaluation of the extrinsic and intrinsic pathway of coagulation was performed by means of PT, APTT, and CAT measurements on (diluted) pooled plasmas from goats, pigs, rabbits, rats, mice, and humans. Plasma anti-FXa activity was assessed by determining the rate of recombinant hFXa inhibition through chromogenic activity analyses and immunoblotting. In general, rabbit, rat, and mouse plasmas exhibited robust clotting upon stimulation of both the extrinsic and intrinsic pathway, produced more thrombin during CAT upon plasma dilution, and displayed relatively high hFXa inhibitory activities. By comparison, goat, porcine, and human plasma displayed a similar profile in PT and APTT assays, produced less thrombin during CAT upon plasma dilution, and displayed comparable hFXa inhibitory activities. In conclusion, the observed differences in clotting parameters and anti-hFXa activity point to a higher anticoagulant threshold in plasma from rabbits, rats, and particularly in mice relative to human, goat, and porcine plasma. Finally, rat plasma was found to be more relevant to the preclinical assessment of human FX(a) in comparison to murine plasma.

Background Activated coagulation factor XIa (FXIa) is an impurity and primary source of procoagulant activity in thrombosis‐implicated immune globulin (IG) products. Several assays, of varying quality and precision are used to assess FXIa‐like procoagulant activity in units relevant to their respective principles. Objectives To advance unified reporting, we sought to employ the World Health Organization reference reagents (RRs) to present the results of differing methodologies in units of FXIa activity and rank the sensitivity and robustness of these methodologies. Methods RR 11/236 served as a calibrator in several FXIa‐sensitive blood coagulation tests: two commercial chromogenic FXIa assays (CAs); a nonactivated partial thromboplastin time (NaPTT); an in‐house fibrin generation (FG) assay; an in‐house thrombin generation (TG) assay; and an assay for FXIa‐ and kallikrein‐like proteolytic activities based on cleavage of substrate SN13a. Some assays were tested in either normal or FXI‐deficient plasma. Results Each method demonstrated a sigmoidal dose‐response to RRs. NaPTT was the least sensitive to FXIa and the least precise; our in‐house TG was the most sensitive; and the two CAs were the most precise. All methods, except for SN13a, which is less specific for thrombotic impurities, gave comparable (within 20% difference) FXIa activity assignments for IG lots. Conclusions Purified FXIa reference standards support quantitation of FXIa levels in IG products in all tested assay methodologies. This should help to standardize the measurement of thrombotic potentials in IG products and prevent products exhibiting high procoagulant activity from distribution for patient use. Further research is needed to address the effect of IG product‐specific matrixes on assay performance.

Highlights • Non-severe COVID-19 patients have abnormal laboratory investigations. • Patients with prolonged pretreatment APTT have a longer isolation length. • Patients with elevated eosinophils after treatment have a shorter isolation length. • A nomogram could help to predict isolation probability at 11-, 16- and 21-day., Background Majority coronavirus disease 2019 (COVID-19) patients are classified as mild and moderate (non-severe) diseases. We aim to develop a model to predict isolation length for non-severe patients. Methods Among 188 non-severe patients, 96 patients were enrolled as training cohort to identify factors associated with isolation length via Cox regression model and develop a nomogram. Other 92 patients formed as validation cohort to validate nomogram. Concordance index (C-index), area under the curve (AUC) and calibration curves were used to evaluated nomogram. Results Increasing absolute eosinophil count (AEC) after admission was correlated with shorter isolation length (P = 0.02). Baseline activated partial thromboplastin time (APTT) > 30 s was correlated with longer isolation length (P = 0.03). A nomogram to predict isolation probability at 11-, 16- and 21-day was developed and validated. The C-indices of training and validation cohort were 0.604 and 0.682 respectively. Both cohorts showed a good discriminative ability (AUC, 11-day: 0.646 vs 0.730; 16-day: 0.663 vs 0.750; 21-day: 0.711 vs 0.783; respectively) and calibration power. Conclusions Baseline APTT and dynamic change of AEC were two significant factors associated with isolation length of non-severe patients. Nomogram could predict isolation probability for each patient to estimate appropriate quarantine length.

Essentials Prekallikrein (PK) deficiency is a recessive trait with isolated aPTT prolongation. KLKB1 c.451dupT is common in Nigerians (7/600 alleles) and absent in a European group (0/600). To date, all genotyped PK-deficient patients of African ancestry were homozygous for 451dupT. Diagnostics of isolated aPTT prolongation in African descendants should include PK testing. ABSTRACT: Background Severe prekallikrein deficiency (PK deficiency) is an autosomal-recessive condition thought to be very rare. Recently we reported that the previously unnoticed variant c.451dupT, p.Ser151Phefs*34 in KLKB1, which is listed in databases aggregating genome data, causes PK deficiency and is common in Africans according to gnomAD (allele frequency 1.43%). Patients/Methods The most common African (c.451dupT) and European (c.1643G>A, p.Cys548Tyr) PK deficiency causing KLKB1 variants were analyzed in two population-based collectives of 300 Nigerian and 300 German subjects. Genome databases were evaluated for variant frequencies and ethnicity of the subjects. The geographic origin of PK-deficient cases due to 451dupT was assessed. Results Two of five patients with PK deficiency caused by homozygous 451dupT were African, one African American, one from Oman, and one of unknown origin. The frequency of 451dupT was 1.17% in the Nigerian collective (7/600 alleles); none had Cys548Tyr. Subjects with 451dupT were found among different Nigerian ethnicities. Both variants were absent in the European collective. Database research was compatible with these findings, even though mainly data of African Americans (451dupT: 1.12%-1.78%) was accessible. A relevant number of non-American Africans are included only in the 1000Genomes collective: 451dupT frequency was 1.29% in native Africans and 1.56% in African Caribbeans. Conclusions This study underlines the higher prevalence of PK deficiency among people with African descent compared to Europeans. In order to avoid delay of necessary surgical procedures in patients of African origin, diagnostic algorithms for isolated, unexplained, activated partial thromboplastin time prolongation in these subjects should include PK deficiency screening.

Background Several routine coagulation tests have been developed to give insight in the coagulation pathway. The laboratory diagnostical process consists of 3 phases, the pre-analytical, analytical and post-analytical phase; however, the pre-analytical phase is most sensitive to errors. The amount of time blood is stored, can affect the measurements of these coagulation tests and result in an incorrect conclusion. Therefore, we performed experiments to determine the maximal storage time, centrifuged blood samples can be reliably measured. Methods Citrated whole blood from hospital patients, who were tested for routine coagulation, was collected in 2.7 mL citrate tubes. These whole blood samples were centrifuged and the plasma was stored on top of the cell pellet at room temperature. After 2 h, 4 h, 6 h, 12 h and 24 h, the prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin activity, D-dimer concentration and thrombin time were measured using Sysmex CS2100 coagulation analysers. Results and conclusion Analytical evaluation of routine coagulation tests resulted in various significant differences and large variations between the various time intervals. Our results indicated that the PT and INR can be measured up till 24 h of storage. Centrifuged blood for measuring the fibrinogen concentration, antithrombin activity, D-dimer concentration and thrombin time can be stored up to 4 h, while 2 h of storage might already be too long for obtaining reliable aPTT measurements.

The present work deals with the extraction and purification of chondroitin sulfate/dermatan sulfate from skin (CSG) and bone (CBG) of corb (Sciaena umbra). Electrophoresis of these polymers in barium acetate buffer on cellulose acetate revealed two fractions similar to dermatan sulfate and chondroitin sulfate. The in vivo anticoagulant activity of both chondroitin sulfate/dermatan sulfate (CS/DS) were evaluated, at 25 and 75 mg kg−1 of body weight (b.w), using activated partial thromboplastin time (aPTT), prothrombine time (TT) and thrombin time (PT) tests. Results showed that aPTT of CSG and CBG at 75 mg kg−1 of b.w were prolonged by 1.59 and 1.48-fold respectively, compared with the control. Further, toxicity studies on liver performed by the catalytic activity of transaminases in plasma, oxidative stress markers and hepatic morphological changes demonstrated that CSG and CBG at both doses are not toxics. In summary, the higher activity and lower toxicity of both CS/DS, especially at 25 mg kg−1 of b.w, recommended these compounds as a better drug candidate.

Background Direct oral anticoagulants targeting factor Xa (DXaIs) are administered as prophylaxis for various venothrombotic diseases without routine monitoring required. However, assessment of their anticoagulant effects is necessary to prevent severe events, including major bleeding and/or refractory thrombosis. Objectives We examined the correlation of ratio of inhibited thrombin generation (RITG), determined using a novel assay based on dilute prothrombin time (dPT), with coagulant markers and laboratory test results to show drug effects. In addition, RITG usefulness as a confirmation test for DXaI therapy was investigated. Methods Citrated plasma samples were obtained from patients treated with rivaroxaban (n = 882), apixaban (n = 1214), or edoxaban (n = 820) at 4 different institutions in Japan. Laboratory tests, including prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer, and plasma concentrations of DXaIs, were conducted, with drug concentrations divided into peak and trough groups, within and after 5 h of administration. Results In each DXaI group, RITG was positively correlated with PT, APTT, and drug concentration, and negatively with D-dimer. RITG fluctuation during the peak and trough periods reflected the anticoagulant activity characteristic of each DXaI, which was different from blood concentration fluctuations. RITG showed a significant decrease in cases with thrombosis, while that was increased in those with hemorrhage. Conclusion We developed RITG, a novel measurement method based on dPT. RITG represents residual coagulation ability in plasma samples, and is useful for assessment of bleeding and thrombotic tendencies in DXaI patients. RITG can be utilized to confirm the effectiveness of oral anticoagulation therapy with DXaI agents.

This study investigates conformational aspects of ulvans (F2) and their polycarboxyl derivatives obtained through periodate–chlorite oxidation (C3) followed by DEAE-Sephacel fractioning (C3b and C3c). Size exclusion chromatography coupled with laser light scattering and viscometric detection, in addition to circular dichroism (CD) and molecular modeling analyses, suggested that F2 had a compact sphere conformation with a helical motif as secondary structure. In contrast, all the polycarboxyl ulvans showed a random coil conformation, although C3c (NaSO3− 21.0%; COO− 1.81 mmol·g−1; Mw 18 kg·mol−1) had a more rigid and constrained backbone than C3 (NaSO3− 21.0%; COO− 1.81 mmol·g−1; Mw 49 kg·mol−1), largely due to its higher sulfate and carboxyl content. Despite the higher ionic character of C3c, its anticoagulant activity (ACA), determined by activated partial thromboplastin time (APTT) assay, was not improved compared to that of C3. Moreover, C3b (NaSO3− 14.1%; COO− 1.23 mmol·g−1; Mw 8.1 kg·mol−1) had higher activity than F2 (NaSO3− 20.6.%; COO− 0.36 mmol·g−1; Mw 123 kg·mol−1), even with its lower sulfate content and molar mass. These results suggest that the ACA of polycarboxyl ulvans relies on carboxyl and sulfate content and may depend, in addition, on a proper flexible conformation.

Introduction Different coagulation indices for direct oral anticoagulants (DOACs) exist in clinical practice, but limited data are available for the diagnostic power of these indices. This review and meta-analysis aims to explore the diagnostic value of coagulation indices for DOACs. Materials and methods PubMed, Web of Science, EMBASE, Clinical Trials.gov , and the Cochrane Library were searched from inception of each database to 15 February 2020. Studies reporting a relationship between coagulation indices and the gold standard (liquid chromatography/tandem mass spectrometry) were included in the analysis. Results Sixteen articles from 9169 citations evaluating the performance of coagulation indices were included in this review. A total of 236, 273, 273 rivaroxaban samples were included to assess the diagnostic power of anti-Xa activity (AXA), prothrombin time (PT), combined PT and activated partial thromboplastin time, respectively. A total of 268 dabigatran samples were included to assess the diagnostic performance of diluted thromboplastin time (dTT). AXA calibrated by rivaroxaban showed a sensitivity of 0.98 (95% confidence interval (CI): 0.91–0.99) and a specificity of 0.98 (95% CI: 0.94–0.99) at the threshold of 30 ng/mL. For dabigatran, the combined sensitivity of dTT was 0.76 (95% CI: 0.66–0.84) and combined specificity was 0.97 (95% CI: 0.92–0.99). Conclusions DOAC-specific calibrated AXA was a good index to indicate concentration for rivaroxaban and apixaban. More studies on edoxaban and betrixaban are in need. Diluted TT, thrombin inhibitor assay, and ecarin-based assays were potential to measure dabigatran concentration. Due to the limited data, results should be validated in the future.

This guidance focuses on methodological aspects of lupus anticoagulant (LA) testing, as well as interpretation of results for clinicians. The main changes in how to test for LA compared with the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee 2009 guidelines, in the preanalytical phase are more detailed recommendations on how to handle testing in anticoagulated patients, and the timing of testing. Also, routine coagulation tests are advised to obtain more information on the coagulation background of the patient, and when necessary, anti-Xa activity measurement for heparins or specific assays for direct oral anticoagulants should be performed. The three-step procedure with two test systems (diluted Russell's viper venom time and activated partial thromboplastin time [aPTT]) is essentially not changed. Silica remains the preferable activator in the aPTT assays, but ellagic acid is not excluded. We advise simultaneous performance of the mixing and confirmatory step, in each sample with a prolonged screening test. The confirmatory step can also be performed on a mixture of patient plasma and normal pooled plasma. Cutoff values should be established in-house on at least 120 normals, with transference of the manufacturer's cutoffs as an alternative. Reporting of results has not been changed, although more attention is focused on what clinicians should know. Patient selection for LA testing has been expanded.

Highlights • COVID-19 spread rapidly around the world. • Assessed the abnormal coagulation parameters in infected patients. • Coagulopathy could be considered as a risk factor for disease severity and mortality of COVID-19. • Help clinicians to identify the incidence of poor outcomes in COVID-19 patients., Background To figure out whether abnormal coagulation parameters are associated with disease severity and poor prognosis in patients with 2019 Corona Virus Disease (COVID-19). Methods A systematic literature search was conducted using the databases PubMed, Embase, and Web of sciences until April 25, 2020. We included a total of 15 studies with 2277 patients. Platelet count (PLT), prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer (D-D) and fibrinogen (FIB) were collected and analyzed. The statistical results were expressed the effect measure by mean difference (MD) with the related 95% confidence interval (CI). Results The PLT level of severe patients was lower than that of mild patients, while the levels of PT, D-D and FIB were higher than those of mild patients (P 0.05). Compared to Non-ICU patients, PT of ICU patients was significantly longer (P 0.05). The funnel plot and Egger's Regression test demonstrated that there was no publication bias. Conclusions Our data support the notion that coagulopathy could be considered as a risk factor for disease severity and mortality of COVID-19, which may help clinicians to identify the incidence of poor outcomes in COVID-19 patients.

International audience; The present study was undertaken to establish a distinct relationship between blue crab chitosan (Cs) acetylation degree (AD) and molecular weight (Mw) and its structural features, thermal properties and bioactivity. Therefore, chitosans with different AD were prepared and Cellulase was used to produce Cs derivatives with decreasing Mw. Results clearly display a decrease of the ordered structure of Cs, with the increase of AD and the decrease of Mw. Thermal stability/degradation screening disclose a greater thermal resistance for Cs with lower AD and higher Mw. The anti-adhesive potential of Cs was, additionally, studied, as function of AD and Mw. The effectiveness of Cs in preventing biofilm adhesion was strongly influenced by its AD and Mw, with the lowest inhibition values for higher AD and lower Mw. Interestingly, the effectiveness of Cs in disrupting pre-formed biofilms increased with decreasing Mw. Moreover, Cs derivatives were found to be advantageously efficient in prolonging human blood clotting times, based on data of activated partial thromboplastin time, Quick time and thrombin time assays, typically for the intrinsic coagulation pathway. Accordingly, depending on the predicted application of Cs, either in food, biomedical and pharmaceutical industries, AD and Mw are critical traits to be inevitably reflected on.

Introduction One of the main advantages of using anti-Xa instead of activated partial thromboplastin time in monitoring of unfractionated heparin (UFH) therapy relies on its hypothesized standardization, with a unique therapeutic range defined to be 0.30 to 0.70 IU/mL. The aim of the present study was to compare the inter-reagent agreement of anti-Xa activity. Methods Citrate tubes were obtained from 104 inpatients on UFH. Plasma samples were stored frozen in aliquots at -70°C before being shipped to three accredited coagulation laboratories to be evaluated for anti-Xa activity using their routine assay(s). Pooled normal plasmas spiked with dilutions of the 6th International Standard of UFH to achieve anti-Xa activities up to 1.0 IU/mL were evaluated using the same techniques. Results In the plasmas from patients on UFH, the median anti-Xa activity ranged from 0.37 IU/mL with one reagent to 0.57 IU/mL with another; results were in between (0.45 IU/mL) using two other reagents. Comparisons of results obtained using the different reagents demonstrated unacceptable bias up to 0.24 IU/mL between some reagents (41% difference). The concordance as whether anti-Xa activities measured using different reagents were within or outside the therapeutic range was between 0.411 and 0.939 (kappa). Similar discrepancy was demonstrated for anti-Xa activities when evaluating normal plasma spiked with the International Standard. A discrepancy of the same order of magnitude was demonstrated in the 2017 External Quality Assessment Program provided by the External Quality Control in Assays and Tests exercises. Conclusions The reported discrepancy between test results obtained using different anti-Xa assays clearly suggests a lack of standardization of that assay with potentially significant impact on the patients' anticoagulation.

Purpose To assess safety and efficacy of a modified rapid hemostasis protocol for distal transradial access (TRA). Materials and Methods A single-center retrospective study of patients undergoing percutaneous image-guided procedures from a distal TRA with rapid deflation hemostasis protocol was performed. Between March 2017 and August 2019, 593 procedures in 434 patients were performed. Mean patient age was 63.5 y (range, 18–94 y). Results The most common procedures were transarterial chemoembolization (218; 36.8%), abdominal and pelvic embolization (116; 19.6%), yttrium-90 mapping (115; 19.4%), yttrium-90 administration (84; 14.2%), and diagnostic angiography (44; 7.4%). Mean (range) values for clotting parameters were international normalized ratio 1.2 (0.9–3.2), partial thromboplastin time 33.5 s (26–44 s), and platelets 23.4 × 109/L (37–552 × 109/L). A hematoma developed in 7 (1.2%) patients. No radial artery occlusions were encountered during follow-up. Nursing intensity was defined as the number of minutes after the procedure required for assessing and managing the access site for bleeding. The mean nursing intensity was 25.1 min (range, 25–40 min). Conclusions The rapid deflation hemostasis protocol for distal TRA at the anatomical snuffbox was feasible and safe. No significant difference or association was found between hematoma formation and clotting parameters after the procedure or type of vascular access equipment used.

BACKGROUND: The severe inflammatory state secondary to COVID-19 leads to a severe derangement of hemostasis that has been recently described as a state of disseminated intravascular coagulation (DIC) and consumption coagulopathy, defined as decreased platelet count, increased fibrin(ogen) degradation products such as D-dimer, as well as low fibrinogen. AIMS: Whole blood from 24 patients admitted at the intensive care unit because of COVID-19 was collected and evaluated with thromboelastography by the TEG point-of-care device on a single occasion and six underwent repeated measurements on two consecutive days for a total of 30 observations. Plasma was evaluated for the other parameters of hemostasis. RESULTS: TEG parameters are consistent with a state of hypercoagulability as shown by decreased values, and increased values of K angle and MA. Platelet count was normal or increased, prothrombin time and activated partial thromboplastin time were near(normal). Fibrinogen was increased and D-dimer was dramatically increased. C-reactive protein was increased. Factor VIII and von Willebrand factor (n = 11) were increased. Antithrombin (n = 11) was marginally decreased and protein C (n = 11) was increased. CONCLUSION: The results of this cohort of patients with COVID-19 are not consistent with acute DIC, rather they support hypercoagulability together with a severe inflammatory state. These findings may explain the events of venous thromboembolism observed in some of these patients and support antithrombotic prophylaxis/treatment. Clinical trials are urgently needed to establish the type of drug, dosage, and optimal duration of prophylaxis.

Background and aims The increased risk of cardiovascular disease under hypercholesterolemia is due to associations between oxidized low-density lipoprotein (ox-LDL) and lipoprotein-associated phospholipase A2 (Lp-PLA2) and between ox-LDL and coagulant profiles. We investigated the impact of different ox-LDL levels on coagulation time and plasma metabolomes in subjects with borderline hypercholesterolemia. Methods and results One hundred thirty-one subjects with borderline hypercholesterolemia (serum cholesterol ≥200 mg/dL) were divided into low ox-LDL (n = 66) and high ox-LDL (n = 65) groups. After adjusting for confounding factors, the high ox-LDL group exhibited a significantly decreased activated partial thromboplastin time (aPTT) and prothrombin time (PT) and increased Lp-PLA2 activity. Compared to the low ox-LDL group, the high ox-LDL group exhibited significantly increased intensities of 17 lysophosphatidylcholines (lysoPCs) and 7 lysophosphatidylethanolamines (lysoPEs). Ox-LDL was inversely correlated with aPTT and PT and positively correlated with Lp-PLA2 activity. Positive correlations were also found among ox-LDL, Lp-PLA2 activity, lysoPCs, and lysoPEs. LysoPCs and lysoPEs were inversely correlated with PT and aPTT. The identified plasma metabolites, including amino acids, fatty acid amides, acylcarnitines, and lysophospholipids, were significantly upregulated in the high ox-LDL group. Conclusion High ox-LDL levels may be involved in the development of a procoagulant state in subjects with borderline hypercholesterolemia by increasing Lp-PLA2 activity and lysoPC and lysoPE levels.

There is an inter-relationship between thrombosis and inflammation. Previously, we have shown the importance of P-selectin in thrombogenesis and thrombus resolution in many preclinical animal models. The role of E-selectin has been explored in rodent models and in a small pilot study of clinical calf vein deep venous thrombosis. The purpose of this study was to determine the role of E-selectin in thrombosis in a primate model of proximal iliac vein thrombosis, a model close to the human condition.Iliac vein thrombosis was induced with a well-characterized primate model. Through a transplant incision, the hypogastric vein and iliac vein branches were ligated. Thrombus was induced by balloon occlusion of the proximal and distal iliac vein for 6 hours. The balloons were then deflated, and the primates recovered. Starting on postocclusion day 2, animals were treated with the E-selectin inhibitor GMI-1271, 25 mg/kg subcutaneously, once daily until day 21 (n = 4). Nontreated control animals received no treatment (n = 5). All animals were evaluated by magnetic resonance venography (MRV); evaluation of vessel area by ultrasound, protein analysis, hematology (complete blood count), and coagulation tests (bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen, and thromboelastography) were performed at baseline, day 2, day 7, day 14, and day 21 with euthanasia. In addition, platelet function and CD44 expression on leukocytes were determined.E-selectin inhibition by GMI-1271 significantly increased vein recanalization by MRV vs control animals on day 14 (P .05) and day 21 (P .0001). GMI-1271 significantly decreased vein wall inflammation by MRV with gadolinium vein wall enhancement vs control also on day 14 (P .0001) and day 21 (P .0001). The thromboelastographic measure of clot strength (maximum amplitude) showed significant decreases in animals treated with GMI-1271 vs controls at day 2 (P .05) and day 7 (P .05). Animals treated with GMI-1271 had significant vessel area increase by day 21 vs controls (P .05) by ultrasound. Vein wall intimal thickening (P .001) and intimal fibrosis (P .05) scores were significantly decreased in GMI-1271-treated animals vs controls. Importantly, no significant differences in hematology or coagulation test results were noted between all groups, suggesting that E-selectin inhibition carries no bleeding potential. GMI-1271 did not affect platelet function or aggregation or CD44 expression on leukocytes. In addition, no episodes of bleeding were noted in either group.This study suggests that E-selectin modulates venous thrombus progression and that its inhibition will increase thrombus recanalization and decrease vein wall inflammation, without affecting coagulation. The use of an E-selectin inhibitor such as GMI-1271 could potentially change how we treat deep venous thrombosis.

Introduction Bivalirudin is an alternative to heparin anticoagulation in infants and children in the setting of extracorporeal life support (ECLS). While activated partial thromboplastin time (aPTT) is widely accepted as the standard test to monitor bivalirudin therapy, the usefulness of thromboelastometry (ROTEM) to monitor bivalirudin infusion in the setting of ECLS is unknown. Objective We aimed to assess the utility of ROTEM in monitoring hemostasis and bivalirudin effect in children on either extracorporeal membrane oxygenation (ECMO) or ventricular assist devices (VAD) compared to standard plasma based coagulation assays. Methods A retrospective study of children undergoing bivalirudin infusion for ECMO/VAD support from a tertiary care pediatric hospital (January 2017–June 2018) was performed. ROTEM assays for extrinsic (EXTEM) and intrinsic (INTEM) coagulation pathways, INTEM with heparinase (HEPTEM), fibrin formation (FIBTEM) with measurement of the clotting time (CT) and maximum clot firmness (MCF) were compared to routine hemostasis testing including: aPTT, aPTT Hepzyme (HPTT), prothrombin time (PT), fibrinogen and platelet count. Results One hundred and six blood samples from 18 children were tested. There was a strong positive correlation between HPTT and HEPTEM CT, and moderate correlation between aPTT and INTEM CT. The bivalirudin dose did not correlate with any test, but displayed strong age-dependence, with infants requiring higher doses of bivalirudin to maintain therapeutic targets. Excellent correlation was found between FIBTEM MCF values and fibrinogen, but FIBTEM overestimated fibrinogen level when platelet count was >300 × 109/L. Heparin-like effect was identified in 39% of specimens, and an improved correlation between aPTT and INTEM CT was observed in specimens without heparinoids. Conclusions In the setting of bivalirudin therapy, prolongation of CT on INTEM and HEPTEM showed moderate to strong correlation with aPTT and HPTT, and therefore, may provide a good alternative to these assays. In addition, HPTT and HEPTEM CT might be preferable for monitoring bivalirudin in the setting of ECLS due to frequent detection of heparin-like effect.

Introduction Pit viper bites are a source of significant morbidity and mortality. Pit viper bites can cause venom-induced consumptive coagulopathy (VICC), typically evaluated with laboratory-based conventional coagulation tests (CCTs). However, CCTs require a laboratory and average 1 h to conduct. Thromboelastography (TEG) provides real-time, point-of-care tests of coagulation that are fast and require no separate laboratory facilities, which could be advantageous in both hospital and austere settings. However, the relative efficacy of TEG versus CCTs was unclear, particularly at low venom concentrations. Therefore, the objectives of this study were to test human blood with various concentrations of pit viper venom using CCTs and TEG to determine dose-dependent changes, lowest observed effect concentration (LOEC), and sensitivity to detecting samples out of normal diagnostic range. Methods Blood samples from 20 volunteers were mixed with varying concentrations of western diamond back rattlesnake (Crotalus atrox) venom based on the mouse LD50IV (none, 0.5%, 1%, 2%, 33%, 66%, and 100% LD50IV). Samples were split and assessed with both CCTs including prothrombin time (PT), international normalized ratio (INR), partial thromboplastin time (PTT), fibrinogen, and D-dimer, along with TEG measures of reaction time (R), kinetic time (K), rate of clot formation (α-angle), and clot strength (MA). Data were analyzed as dose-dependent concentration-based changes in raw values and in percent of samples exceeding diagnostic thresholds using ANOVA and nonparametric statistics at the p Results All evaluations showed significant concentration-dependent changes, and 100% of samples exceeded diagnostic thresholds at 33%LD50IV and above, save D-dimer. At 0.5%LD50IV, R, K, α-angle, PT, and INR were significantly different from controls, and at 1%LD50IV, mean values exceeded diagnostic thresholds for R, K, α-angle, MA, PT, and INR, but not for PTT, D-dimer, or fibrinogen. At 2%LD50IV, 100% of samples were out of normal range for K, α-angle, and PT. Conclusion TEG is effective in coagulopathy evaluations of in vitro simulated pit viper envenomation. At low venom concentrations, TEG performed as well or better than the majority of CCTs. These findings provide empirical evidence supporting the use of TEG to rapidly and accurately evaluate VICC.

The efficacy of fresh frozen plasma (FFP) transfusion in enhancing thrombin generation in patients with cirrhosis and impaired conventional coagulation tests has not been sufficiently explored. Thus, we aimed to assess the effect of FFP transfusion on thrombin generation in these patients.Fifty-three consecutive patients receiving a standard dose of FFP to treat bleeding and/or before invasive procedures - if international normalized ratio (INR)/prothrombin time (PT) ratio were ≥1.5 - were prospectively enrolled. The primary endpoint was the amelioration of endogenous thrombin potential (ETP) with thrombomodulin (ETP-TM) after transfusion, which corresponds to the total amount of generated thrombin. INR/PT ratio and activated partial thromboplastin time (aPTT) were also assessed before and after transfusion.FFP enhanced ETP-TM by 5.7%, from 973 (731-1,258) to 1,028 (885-1,343 nM × min; p = 0.019). Before transfusion, evidence of normal or high ETP-TM was found in 94% of patients, even in those with bacterial infections. Only 1 (1.9%) patient had ETP-TM values reverting to the normal range after transfusion. Notably, no patients with low ETP-TM had bleeding. The median decrease in ETP-TM was 8.3% and the mean was 12.8% in 18 (34%) patients after transfusion (from 1,225 [1,071-1,537] to 1,124 [812-1,370] nM × min; p ≤0.0001). Similar responses to FFP transfusion were observed in patients with compensated and acute decompensated cirrhosis, acute-on-chronic liver failure, infection or shock. FFP significantly ameliorated INR and aPTT values (p0.0001), but in a minority of patients the values were reduced to less than the cut-off point of 1.5.FFP transfusion enhanced thrombin generation and ameliorated conventional coagulation tests to normal values in a limited number of patients, and slightly decreased thrombin generation in 34% of cases.Transfusion of fresh frozen plasma in patients with cirrhosis only slightly improves coagulation test values in a limited number of patients and even appears to worsen them in a third of cases. Transfusion for the purpose of preventing or treating bleeding events could cause inherent risks and costs without clear benefits.