Thrombin Generation Assay and by-Passing Therapies in Patients with Inhibitors,

Abstract Abstract 3322 No routine test is available for monitoring bypassing agent therapy in patients with inhibitors. General clotting tests such as PT, aPTT and factor activities do not reflect overall thrombin generation and are insensitive to hypercoagulation and hypocoagulation. In this study, we aimed to investigate the importance of thrombin generation assay (TGA) in monitoring hemostasis during factor supplementation in hemophilia patients with and without inhibitor. Study group consisted of 39 patients (27 hemophilia A, 8 hemophilia B, one vWD-3, two FVII def. and one FX def.). All patients were male. Seven out of 27 hemophilia A patients had an inhibitor. The mean age was 17±9.7 years (range: 3–55). A total of 59 (inhibitor positive=19) bleeding episodes and/or surgical interventions were evaluated. Acute bleeding episodes were classified as acute hemarthrosis (n=21), soft tissue hemorrhages (n=6), oral /nasal hemorrhages (n=7), hematuria (n=2) or GIT hemorrhages (n=3). Twenty major or minor surgical interventions were classified as radioisotope synovectomy (n=11), teeth extractions (n=2), circumcision (n=1), port-a-cath removal (n=1); hemorrhoid operation (n=1) or open synovectomy and arthroplasty n=4). rFVIIa and aPCC therapies were administered to inhibitor-positive patients. PPP was always prepared within 30 min of venipuncture. PT, aPTT and FVIII activities were measured in plasma from citrated blood samples taken before treatment of patients for bleeding or for surgery preparation. Before TGA test, aliquoted PPP was stored for 3 months at −80°C, and all samples were assessed together. Lab parameters were evaluated at basal levels and after 1 hour of factor therapy. These tests were repeated when clinical hemostasis was obtained within 24 hours of the post-op period. PT, aPTT, FVIII activities were assessed by Siemens kits with CA-1500 (Sysmex–Siemens). The Calibrated Automated Thrombogram (CAT; Thrombinoscope BV, Maastricht, The Netherlands) method was used for the TGA. No difference was found between 1th and 24th hour clinical responses after rFVIIa and aPCC treatment (P= 0.96) in hemophilic patients with inhibitor. Basal, first hour and 24th hour TGA lag time values were significantly shorter in hemophilic patients with inhibitor than in inhibitor-free patients (P= <.01). Basal TGA parameters (ETP, peak thrombin height, and time to peak values were significantly better in hemophilic patients without inhibitor than in those with inhibitor (P= <.01). No difference was found between the first hour and 24th hour TGA parameter values between hemophilic patients without/with inhibitor after factor therapy. TGA lag time values measured 24 hours post-event were significantly shorter in rFVIIa than aPCC treatment in hemophilic patients with inhibitor (P=.04). First hour ETP and first hour and 24 hour peak thrombin height were significantly higher in aPCC than rFVIIa treatment in hemophilic patients with inhibitor (P=.01). First hour TEG parameter (R, K and alpha angle degree) values were found significantly in aPCC (12 episodes)than rFVIIa treatment (7 episodes) (P=.03). First hour and 24th hour INR values were significantly shorter in rFVIIa than aPCC (P= <.01). No association was found between first hour clinical responses and TGA parameters after inhibitor bypassing agent treatment. In this study, before and after bleeding episode treatment/surgery prophylaxis, basal, 1st and 2–24th hours lag time values of inhibitor-positive patients were significantly smaller than inhibitor-negative patients. Basal TGA parameters such as ETP, peak thrombin height, and time to peak thrombin values of hemophilic patients without inhibitor were significantly better than those of hemophilic patients with inhibitor. When hemophilic patients with or without inhibitor were evaluated for accurate clinic responses at 24 hours after factor replacement treatment, the clinical response was significantly better in the inhibitor-negative group. As a conclusion, for monitoring hemostasis in inhibitor patients related severe bleeding and major operations, TGA test may be used for most rational using of by-passing therapies. Disclosures: Kavakli: NovoNordisk: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Baxter: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

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Factor VIII Efficacy and Tissue Factor Levels in Hemophilia A Patients Undergoing Total Knee Replacement.

Blood ◽

10.1182/blood.v104.11.4029.4029 ◽

2004 ◽

Vol 104 (11) ◽

pp. 4029-4029

Author(s):

Wolfgang Wegert ◽

Manuela Krause ◽

Inge Scharrer ◽

Ulla Stumpf ◽

Andreas Kurth ◽

...

Keyword(s):

Total Knee Replacement ◽

Plasma Levels ◽

Thrombin Generation ◽

Hemophilia A ◽

Lag Time ◽

Major Surgery ◽

Plasma Samples ◽

Time To Peak ◽

Thrombin Generation Assay ◽

Total Knee

Abstract The changes of tissue factor (TF) blood levels in patients undergoing major surgery has been reported presenting controversial data. Whether this TF is hemostatically active or if it interacts with other coagulation factors, e.g. FVIII, is still unclear, making thrombotic risk and complications assessment for even more difficult. We analyzed plasma samples from four male patients aged 27–55 with severe hemophilia A without inhibitory antibodies, undergoing total knee replacement, which all gave informed consent. Initial FVIII doses before intervention was 75–80 U/kg. Treatment following intervention was targeted at 100 % FVIII serum levels. None received heparin. No bleeding events occurred during the observation period. The samples were taken at these timepoints (TP): 1. before preoperative FVIII substitution, 2. at the time of first incision (intervention start), 3. at circulation arrest release + 90 s after prosthesis implantation, 4. final suture (intervention end), 5. 24 h and 6. 48 h after intervention to assay procedurally induced TF production. Coagulation analyses were carried out using a fluorometric thrombin generation assay (TGA) in platelet rich plasma (PRP), RoTEG (rotation thrombelastography) in whole blood and a TF ELISA for the plasma samples’ TF levels. Both clotting function tests were started using TF diluted 1:100.000 and calcium chloride 16,7 mM (final conc.). TGA parameters were ETP, PEAK (maximum thrombin generation velocity), TIME TO PEAK, LAG TIME. TGA parameters directly related to thrombin activity (ETP; PEAK) showed no change during the intervention, but a sharp decrease 24 h later with a partial recovery 48 h later. TGA time marks (TIME TO PEAK, LAG TIME) changed in an inverse way, except for the difference from LAG TIME and TIME TO PEAK, which shortened continously after circulation arrest removal. RoTEG was characterized using 4 parameters: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF) and clot formation rate (CFR). After preoperative FVIII substitution, CT decreased by 10 % and CFT by 50 % in 48 h. MCF stayed unchanged during the intervention and the following 24 h, but increased by 20 % at 48 h. CFR increased by 10 % during intervention, and by 20 % from 24 to 48 h. TF ELISA showed preoperative TF plasma levels from 11 to 271 pg/ml. After release of circulation arrest (TP 3) TF concentration increased sharply (4 times the initial value), which was not detectable in the samples taken at TPs 2 and 4. TF levels further increased at TPs 5 and 6 to 170 % and 317 % resp. Altogether, TF plasma levels elevated after major surgery seem to correspond to a potential risk factor for postoperative thrombosis, especially when elevation is induced after intervention. However, functional coagulation assays do not change uniformly, as the thrombin generation assay reflects no marked changes under intervention, but in the period after(24–48 h). Changes in the RoTEG whole blood clotting assay are not dramatic but indicate a thrombophilic shift in coagulation balance also pronouned at 24–48h, too. These results demonstrate that increased coagulability after orthopedic surgery detected using functional clotting assays correlates with increased TF levels, but further studies must be performed to prove this relation in healthy individuals.

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Association rate constants rationalise the pharmacodynamics of apixaban and rivaroxaban

Thrombosis and Haemostasis ◽

10.1160/th14-10-0877 ◽

2015 ◽

Vol 114 (07) ◽

pp. 78-86 ◽

Cited By ~ 24

Author(s):

Georges Jourdi ◽

Virginie Siguret ◽

Anne Céline Martin ◽

Jean-Louis Golmard ◽

Anne Godier ◽

...

Keyword(s):

Thrombin Generation ◽

Factor Xa ◽

Lag Time ◽

Lower Sensitivity ◽

Association Rate ◽

Time To Peak ◽

Thrombin Generation Assay ◽

Direct Inhibitors ◽

Association Rate Constants ◽

Kinetics Of

SummaryRivaroxaban and apixaban are selective direct inhibitors of free and prothrombinase-bound factor Xa (FXa). Surprisingly prothrombin time (PT) is little sensitive to clinically relevant changes in drug concentration, especially with apixaban. To investigate this pharmacodynamic discrepancy we have compared the kinetics of FXa inhibition in strictly identical conditions (pH 7.48, 37 °C, 0.15 M). KI values of 0.74 ± 0.03 and 0.47 ± 0.02 nM and kon values of 7.3 ± 1.6 106 and 2.9 ± 0.6 107 M-1 s-1 were obtained for apixaban and rivaroxaban, respectively. To investigate if these constants rationalise the inhibitor pharmacodynamics, we used numerical integration to evaluate impact of FXa inhibition on thrombin generation assay (TGA) and PT. Simulation predicted that in TGA triggered with 20 pM tissue factor, 100 ng/ml apixaban or rivaroxaban increased 1.8– or 3.0-fold the lag time and 1.4– or 2.0-fold the time to peak, whilst decreasing 1.2– or 3.1-fold the maximum thrombin and 1.7– or 3.5-fold the endogenous thrombin potential. These numbers were consistent with those obtained through the corresponding TGA triggered in plasma spiked with apixaban or rivaroxaban. Simulated PT ratios were also consistent with the corresponding plasma PT: markedly less sensitive to apixaban than to rivaroxaban. Analogous differences in TGA and PT were obtained irrespective of the drug amount added. We concluded that kon values for FXa of apixaban and rivaroxaban rationalise the unexpected lower sensitivity of PT and TGA to the former.

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Thrombin Generation Assay in Plasma from Hemophilia a Patients with or without Inhibitors on Concizumab Prophylaxis: Spiking with rFVIIa or aPCC

Blood ◽

10.1182/blood-2019-122301 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3639-3639

Author(s):

Marianne Kjalke ◽

Mads Kjelgaard-Hansen ◽

Søren Andersen ◽

Ida Hilden

Keyword(s):

Thrombin Generation ◽

Significant Contribution ◽

Hemophilia A ◽

Employment Equity ◽

Breakthrough Bleeding ◽

Thrombin Generation Assay ◽

Bleeding Episodes ◽

Equity Ownership ◽

Bypassing Agents

Introduction: Concizumab is a humanized monoclonal antibody that inhibits tissue factor pathway inhibitor (TFPI). Concizumab is currently in clinical development as a subcutaneous prophylactic therapy for hemophilia A and B patients with and without inhibitors. Breakthrough bleeding episodes experienced by inhibitor patients while on concizumab prophylaxis may be treated with the bypassing agents recombinant activated factor VII (rFVIIa; NovoSeven®) or activated prothrombin complex concentrate (aPCC; FEIBA®). Aim: To investigate the in vitro effect of rFVIIa and aPCC on hemophilia A plasma containing concizumab using a thrombin generation assay and pooled plasma spiked with concizumab or samples from patients treated prophylactically with concizumab. Methods: Pooled hemophilia A plasma was spiked with concizumab at 1, 3 and 10 nM and patient plasma samples from explorer4 (n=16; hemophilia with inhibitors; NCT03196284) and explorer5 (n=30; hemophilia A; NCT03196297) before and during concizumab prophylaxis at steady state exposure levels were assessed. Samples were spiked with rFVIIa (25 or 75 nM) or aPCC (0.25, 0.5 or 1 U/mL), and analyzed using a thrombin generation assay initiated with tissue factor (PPP-Low, Thrombinoscope). The effects of rFVIIa or aPCC in the absence or presence of concizumab were compared using ANOVA methodology. Results: Addition of rFVIIa or aPCC to hemophilia A plasma with or without inhibitors increased peak thrombin generation both in the absence and presence of concizumab. A significant additional effect of rFVIIa and aPCC was observed for all concizumab concentrations spiked to the plasma pool. Overall, the effects of the combination of concizumab and rFVIIa or aPCC were mainly additive; however, a small but statistically significant drug-drug interaction was observed for rFVIIa (25 nM or 75 nM) and aPCC (0.5 U/ml or 1 U/mL) in the presence of 10 nM concizumab. At this concizumab concentration, the additive effect of aPCC corresponded to 68% of the total observed effect and the additive effect of rFVIIa to 85% of the total observed effect. At lower concizumab concentrations (1 and 3 nM), statistically significant drug-drug effects were only observed in combination with aPCC. No excessive thrombin generation above the level obtained with 1 IU/mL recombinant factor VIII (rFVIII) was observed at 1 nM concizumab combined with either rFVIIa (25 and 75 nM) or aPCC 0.5 U/mL. However, addition of 1 U/mL aPCC to 1 nM concizumab resulted in a thrombin peak modestly above the upper 95% confidence interval of the rFVIII range. In the experiments using plasma from patients treated with concizumab, the increase in thrombin peak upon addition of rFVIIa was within or below the range observed by spiking with 1 IU/mL rFVIII. The increase in thrombin peak upon addition of aPCC was within or above the rFVIII range. The effects of concizumab and rFVIIa or aPCC were mainly additive; however, a small, statistically significant contribution caused by drug-drug interaction was observed for concizumab and rFVIIa (75 nM) in both plasma from patients with and without inhibitors, and for 1 U/mL aPCC in plasma from patients with inhibitors. The additive effects of concizumab and rFVIIa corresponded to between 60% (25 nM rFVIIa, plasma without inhibitors) and 75% (75 nM rFVIIa, inhibitor plasma), and the additive effects of concizumab and 1 U/mL aPCC corresponded to 77% of the total observed effects. Conclusions: Addition of rFVIIa or aPCC to hemophilia A plasma with or without inhibitors increased peak thrombin generation as expected both in the absence and presence of concizumab. Thus, the bypassing agents function as expected in plasma containing concizumab. The effects of concizumab and rFVIIa or aPCC were mainly additive. A small but statistically significant contribution was synergistic in accordance with the concizumab mechanism of action (Hilden I et al, Blood, 2012). These in vitro results support the concomitant use of bypassing agents to treat breakthrough bleeding episodes in hemophilia with inhibitor patients on concizumab prophylactic treatment. Disclosures Kjalke: Novo Nordisk A/S: Employment, Honoraria. Kjelgaard-Hansen:Novo Nordisk A/S: Employment, Equity Ownership. Andersen:Novo Nordisk A/S: Employment, Equity Ownership, Honoraria. Hilden:Novo Nordisk A/S: Employment, Equity Ownership, Patents & Royalties.

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FEIBA® and Novoseven® Neutralize the Anticoagulant Effects of a Novel Small Molecule FXIa Inhibitor BMS-986177/JNJ-70033093 in Human Plasma and Whole Blood in Vitro

Blood ◽

10.1182/blood-2020-136378 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 10-11

Author(s):

Matthew W Bunce ◽

Zheng Huang Devine ◽

Madhu Chintala

Keyword(s):

Human Plasma ◽

Whole Blood ◽

Thrombin Generation ◽

Hemophilia A ◽

Lag Time ◽

Publicly Traded ◽

Routine Prophylaxis ◽

Control And Prevention ◽

Bleeding Episodes

Background: FXIa inhibition is a promising antithrombotic drug target. BMS-986177/JNJ-70033093 (BMS-177/JNJ-3093) is a novel small molecular inhibitor of FXIa currently in Phase II clinical trials with the potential for reduced bleeding risk as compared to the currently approved oral anticoagulantsHowever, reversal of anticoagulation may still be required in patients who have uncontrolled or life-threatening bleeding or need an urgent surgical procedure. Aim: To evaluate the ability of nonspecific reversal agents (NSRAs) FEIBA®, NovoSeven®, Kcentra®, Profilnine®, BeneFix®, Novoeight®, and Cyklokapron® to neutralize the anticoagulation of BMS-177/JNJ-3093 in the activated partial thromboplastin time (aPTT), thromboelastography (TEG) and thrombin generation assay (TGA) in vitro using human plasma or whole blood. Method: aPTT and TEG were performed in human plasma and whole blood, respectively, using standard assay procedures. TGA was performed in human plasma using diluted kaolin aPTT reagent (1:10,000). JNJ-3093 was evaluated at different concentrations (0.3 -10 µM) to cover the anticipated exposures in the Phase II clinical trials. The NSRAs were evaluated at the anticipated concentrations according to the dosing information in their respective labels. Results: BMS-177/JNJ-3093 produced concentration dependent increases in aPTT (up to 4.4x at 10 μM); prolongations of lag time in TEG (2.6X); prolongations of lag time (3X) as well as reductions in peak thrombin generation (70%) in TGA. FEIBA® effectively neutralized the anticoagulant effects of JNJ-3093 in aPTT, TEG and TGA. NovoSeven® neutralized the BMS-177/JNJ-3093-induced prolongations in aPTT, prolongations in lag time in TEG and TGA assays and partially restored the peak thrombin generation in TGA. In contrast, all other NSRAs tested had negligible effects or did not show neutralization of anticoagulation induced by BMS-177/JNJ-3093 in the referenced assays Conclusion: These results demonstrate that FEIBA® and NovoSeven® can effectively neutralize the anticoagulant effects of BMS-177/JNJ-3093 in vitro. A clinical study is required to determine if these agents can reverse the anticoagulant effects of BMS-177/JNJ-3093 in patients. Table Disclosures Bunce: Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Huang Devine:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Chintala:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. OffLabel Disclosure: FEIBA: hemophilia A and B patients with inhibitors for: control and prevention of bleeding episodes; use around the time of surgery; routine prophylaxis to prevent or reduce the frequency of bleeding episodes NovoSeven: Treatment of bleeding and prevention of bleeding for surgeries and procedures in adults and children with hemophilia A or B with inhibitors, congenital Factor VII (FVII) deficiency, and Glanzmanns thrombasthenia with a decreased or absent response to platelet transfusions; treatment of bleeding and prevention of bleeding for surgeries and procedures in adults with acquired hemophilia Kcentra: urgent reversal of acquired coagulation factor deficiency induced by vitamin K antagonist therapy in adult patients with need for urgent surgery/invasive procedure or acute major bleeding Profilnine: prevention and control of bleeding in patients with Factor IX deficiency due to hemophilia B BeneFix: control and prevention of bleeding episodes or peri-operative management in adult and pediatric patients with hemophilia B Novoeight: for use in adults and children with hemophilia A for control and prevention of bleeding, perioperative management, and routine prophylaxis to prevent or reduce the frequency of bleeding episodes Cyklokapron: patients with hemophilia for short-term use to reduce or prevent hemorrhage and reduce the need for replacement therapy during and following tooth extraction)

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Factor VIII Supplementation Improves Recombinant VIIa Initiated Thrombin Generation in Hemophilia A Inhibitor Patient Plasmas

Blood ◽

10.1182/blood.v118.21.28.28 ◽

2011 ◽

Vol 118 (21) ◽

pp. 28-28

Author(s):

Bhavya Doshi ◽

Courtney Cox ◽

Bagirath Gangadharan ◽

Christopher B Doering ◽

Shannon L. Meeks

Keyword(s):

Factor Viii ◽

Thrombin Generation ◽

Hemophilia A ◽

Conflicts Of Interest ◽

Factor Viia ◽

Treatment Options ◽

Lag Time ◽

Time To Peak ◽

Fviii Inhibitor

Abstract Abstract 28 Hemophilia A is an X-linked recessive disorder that is caused by a deficiency or defect of factor VIII (fVIII) coagulant protein. Approximately 20–30% of patients with severe hemophilia A develop antibodies (Abs) against fVIII (inhibitors) following fVIII replacement therapy, which makes bleeding episodes more difficult to control. Patients with inhibitors are treated with fVIII-bypassing agents such as recombinant factor VIIa (rfVIIa) or activated prothrombin-complex concentrate. However for unknown reasons, some patients display poor hemostatic response to bypass therapy and improved treatment options are needed. Thrombin generation assays provide an in vitro methodology for monitoring bypass therapy in hemophilia (Turecek PL et al. Pathophysiol Haemost Thromb 2003; Varadi K et al. Haemophilia 2004). Recently, it was demonstrated by us and others that combination of fVIII and by-passing agents potentiates in vitro thrombin production in hemophilia A inhibitor plasma (Klintman J et al. Br J Haematol 2010). In our study we investigated the potentiation fVIII confers to fVIIa initiated in vitro thrombin generation using a panel of anti-fVIII Abs with known epitopes. We showed that kinetics of inhibition and Ab epitope were the dominant factors influencing ability of fVIII to potentiate in vitro thrombin production. Specifically, monoclonal Abs targeting only 2 of 11 epitopes, 1 of 3 non-overlapping A2 epitopes and 1 of 2 non-overlapping C2 epitopes, inhibited thrombin generation in a manner that could not be recovered by fVIII supplementation. Here, we analyzed in vitro thrombin generation in epitope-mapped plasmas from 10 patients with hemophilia A and long-standing inhibitors after addition of fVIIa alone or in conjunction with fVIII. Methods: FVIII inhibitor plasmas from 10 patients with hemophilia A were obtained as part of an IRB approved study at the Emory Comprehensive Hemophilia Center. FVIII inhibitor titers and inhibitor kinetics were determined using a modified Bethesda assay. Samples were classified as having type II inhibitors if undiluted plasma resulted in incomplete inhibition of residual fVIII activity (Meeks SL et al. Blood 2007). Thrombin generation assays were carried out in the presence of 2.25 μg/ml recombinant fVIIa in the presence or absence of 1 U/ml recombinant full-length fVIII using reagents purchased from DiaPharma (West Chester, OH). The parameters analyzed include endogenous thrombin potential (area under thrombin generation curve), peak thrombin concentration, time to peak thrombin, lag time (time to 1/6th of peak thrombin) and index velocity (Vi-peak thrombin divided by time to peak minus lag time). Domain specific epitope mapping was carried out using direct ELISA and human/porcine domain hybrid fVIII proteins. Results: Domain mapping of the Abs in the plasmas identified 2 plasmas with predominantly anti-A2 Abs, 4 with predominantly anti-C2 Abs, 2 with both anti-A2 and anti-C2 Abs, and 2 with antibodies that were porcine fVIII cross-reactive (see Table). Plasmas with inhibitor titers less than 25 BU/ml were more responsive to fVIII supplementation with 6 of 7 having increased thrombin generation. Plasmas harboring even trace anti-A2 Abs were more resistant to increased thrombin generation with fVIII supplementation than plasmas with anti-C2 Abs alone. Conclusion: This study suggests a more favorable response to fVIII supplementation of rfVIIa may be predicted by the presence of anti-C2 Abs or inhibitory titers less than 25 BU/ml. In conjunction with our previous monoclonal Ab data, further mapping of epitopes within the fVIII A2 and C2 domains may help improve the ability to predict positive responses to fVIII supplementation of by-passing agents.PatientInhibitor Titer (BU/ml)DomainFVIII InhibitorThrombin Generation (fVIII + fVIIa vs. fVIIa)122A2Type IIIncreased242A2Type IIEqual384C2, small A2Type IEqual47C2Type IIncreased58C2Type IIIncreased620C2Type IEqual78C2Type IIncreased842C2, small A2Type IEqual922Porcine cross-reactiveType IIIncreased105.2Porcine cross-reactiveType IIncreased Disclosures: No relevant conflicts of interest to declare.

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Role of a thrombin generation assay in the prediction of infection severity

Scientific Reports ◽

10.1038/s41598-021-86915-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Boaz Elad ◽

Gilat Avraham ◽

Naama Schwartz ◽

Adi Elias ◽

Mazen Elias

Keyword(s):

Hospital Mortality ◽

Thrombin Generation ◽

Systemic Infection ◽

Lag Time ◽

Peak Height ◽

Clinical Tool ◽

Time To Peak ◽

Thrombin Generation Assay ◽

Failure Assessment

AbstractThrombin plays a central role in sepsis pathophysiology. The correlation of thrombin generation (TG) assays with infection severity and prognosis, and whether it can be used as a clinical tool, have been poorly explored and are the subjects of our research. We recruited 130 patients with systemic infection between 2016 and 2019. Patients were divided according to infection severity by using the sequential organ failure assessment (SOFA) and quickSOFA (qSOFA) scores. The hemostatic state was analyzed by Calibrated Automated Thrombogram. The primary end points were TG values and the secondary end point was in-hospital mortality. Patients with qSOFA ≥ 2 had a longer lag time (5.6 vs. 4.6 min) and time to peak (8 vs. 6.9 min) than those with lower scores (p = 0.014 and 0.01, respectively). SOFA ≥ 2 had a longer lag time (5.2 vs. 4.3 min), time to peak (7.5 vs. 6.7 min) and lower endogenous thrombin potential (ETP) (1834 vs. 2015 nM*min), p = 0.008, 0.019, and 0.048, respectively. Patients who died (11) had lower ETP (1648 vs. 1928 nM*min) and peak height (284 vs. 345 nM), p = 0.034 and 0.012, respectively. In conclusion TG assays may be a valuable tool in predicting infection severity and prognosis.

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The in vitro addition of idarucizumab to plasma samples from patients increases thrombin generation

Scientific Reports ◽

10.1038/s41598-021-85318-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mojca Božič Mijovski ◽

Rickard E. Malmström ◽

Nina Vene ◽

Jovan P. Antovic ◽

Alenka Mavri

Keyword(s):

Thrombin Generation ◽

Ex Vivo ◽

Lag Time ◽

Plasma Samples ◽

Blood Samples ◽

Time To Peak ◽

Thrombin Generation Assay ◽

Coagulation Tests ◽

Before And After

AbstractDabigatran interferes with many coagulation tests. To overcome this obstacle the use of idarucizumab as an in vitro antidote to dabigatran has been proposed. The aim of this study was to test the effect of idarucizumab as an in vitro antidote to dabigatran in ex vivo plasma samples from routine clinical patients examined by a thrombin generation assay (TGA). From 44 patients with atrial fibrillation five blood samples were collected. Thrombin generation was measured in all samples before and after the addition of idarucizumab. When idarucizumab was added to baseline plasma (no dabigatran), it caused a significantly shorter Lag Time and Time to Peak Thrombin, and a higher Peak Thrombin and Endogenous Thrombin Potential (ETP) of TGA. Similar results were obtained when idarucizumab was added to dabigatran-containing plasma, with TGA parameters comparable to baseline + idarucizumab plasma, but not to baseline plasma. In summary, our study showed that in vitro addition of idarucizumab to plasma samples from patients increases thrombin generation. The use of idarucizumab to neutralize dabigatran in patient plasma samples as well as the clinical relevance of in vitro increased thrombin generation induced by idarucizumab needs further investigation.

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Abstract P683: Thrombin Generation in Plasma of Stroke Patients With Atrial Fibrillation

Stroke ◽

10.1161/str.52.suppl_1.p683 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Sarina Falcione ◽

Gina Sykes ◽

Joseph Kamtchum Tatuene ◽

Danielle Munsterman ◽

Twinkle Joy ◽

...

Keyword(s):

Atrial Fibrillation ◽

Ischemic Stroke ◽

Thrombin Generation ◽

Thrombus Formation ◽

Lag Time ◽

Thrombin Time ◽

Stroke Patients ◽

Time To Peak ◽

Generation Capacity

Background and Purpose: Thrombus formation is central to pathophysiology of stroke in patients with atrial fibrillation. Whether factors in plasma contribute to thrombus generation in patients with atrial fibrillation remains unclear. In this study we sought to determine whether plasma contributes to thrombin generation in patients with atrial fibrillation. Methods: There were 78 acute ischemic strokes with atrial fibrillation and 37 non-stroke controls. Plasma thrombin generation was measured by thrombin generation assay, resulting lag time, peak thrombin, time to peak and area under the curve was assessed. Thrombin generation capacity was compared in stroke patients with atrial fibrillation to non-stroke controls. The relationship to anticoagulation was assessed. In vitro, the effect of anticoagulation on plasma thrombin generation was determined. Results: Thrombin generation capacity was increased (shorter lag time and time to peak) in ischemic stroke patients with atrial fibrillation compared to non-stroke atrial-fibrillation controls (p<0.05 and p<0.01, respectively). Anticoagulation decreased plasma induced thrombin generation. Ischemic stroke patients with atrial fibrillation treated with anticoagulation (DOAC or warfarin) had lower plasma induced thrombin generation compared to atrial-fibrillation patients not on anticoagulation (p<0.05). Thrombin generation by plasma could be further reduced by DOAC in an in-vitro assay. Conclusions: Stroke patients with atrial fibrillation have a higher plasma induced thrombin generation compared to atrial fibrillation controls. Factors in plasma such as leukocyte derived tissue factor likely contribute to thrombus formation in patients with atrial fibrillation. As such, components in plasma may represent new targets to reduce thrombus formation and stroke risk in patients with atrial fibrillation.

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Liraglutide in polycystic ovary syndrome: a randomized trial, investigating effects on thrombogenic potential

Endocrine Connections ◽

10.1530/ec-16-0113 ◽

2017 ◽

Vol 6 (2) ◽

pp. 89-99 ◽

Cited By ~ 10

Author(s):

Malin Nylander ◽

Signe Frøssing ◽

Caroline Kistorp ◽

Jens Faber ◽

Sven O Skouby

Keyword(s):

Thrombin Generation ◽

Polycystic Ovary ◽

Plasminogen Activator Inhibitor ◽

Lag Time ◽

Plasminogen Activator Inhibitor 1 ◽

Cvd Risk ◽

Ovary Syndrome ◽

Time To Peak ◽

Thrombogenic Potential ◽

Activator Inhibitor

Polycystic ovary syndrome (PCOS) is associated with increased risk of venous thromboembolism (VTE) and cardiovascular disease (CVD) in later life. We aimed to study the effect of liraglutide intervention on markers of VTE and CVD risk, in PCOS. In a double-blind, placebo-controlled, randomized trial, 72 overweight and/or insulin-resistant women with PCOS were randomized, in a 2:1 ratio, to liraglutide or placebo 1.8 mg/day. Endpoints included between-group difference in change (baseline to follow-up) in plasminogen activator inhibitor-1 levels and in thrombin generation test parameters: endogenous thrombin potential, peak thrombin concentration, lag time and time to peak. Mean weight loss was 5.2 kg (95% CI 3.0–7.5 kg, P < 0.001) in the liraglutide group compared with placebo. We detected no effect on endogenous thrombin potential in either group. In the liraglutide group, peak thrombin concentration decreased by 16.71 nmol/L (95% CI 2.32–31.11, P < 0.05) and lag time and time to peak increased by 0.13 min (95% CI 0.01–0.25, P < 0.05) and 0.38 min (95% CI 0.09–0.68, P < 0.05), respectively, but there were no between-group differences. There was a trend toward 12% (95% CI 0–23, P = 0.05) decreased plasminogen activator inhibitor-1 in the liraglutide group, and there was a trend toward 16% (95% CI −4 to 32, P = 0.10) reduction, compared with placebo. In overweight women with PCOS, liraglutide intervention caused an approximate 5% weight loss. In addition, liraglutide affected thrombin generation, although not significantly differently from placebo. A concomitant trend toward improved fibrinolysis indicates a possible reduction of the baseline thrombogenic potential. The findings point toward beneficial effects of liraglutide on markers of VTE and CVD risk, which should be further pursued in larger studies.

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