Fibrinolytic Dysregulation Contributes to the Hypercoagulable State in Pulmonary Embolism Patients

Abstract Introduction: The multifactorial and complex pathophysiology of pulmonary embolism (PE) involves dysregulation of hemostatic system including fibrinolytic imbalance, endothelial compromise and generation of thrombotic mediators, along with cellular defects and hemodynamic derangement. It is estimated that 6000 cases of pulmonary embolism and DVT are reported yearly of which 1000 result in death. PE evolves from a pre-existing venous thrombus, obstructing pulmonary artery leading to pulmonary failure. The progression of clot formation results in increase in right ventricular pressure, systemic hypoperfusion, hypoxemia ischemia and eventually multi organ failure. Fibrinolytic dysregulation and generation of procoagulant mediators result in increased clot burden and lead to adverse outcomes. Profiling of the component of the fibrinolytic system for such mediators as the activators and inhibitors of fibrinolysis, vWF and cellular microparticles may provide additional insights into the pathogenesis of PE. The purpose of this study is to profile plasma samples from PE patients for various mediators of hemostatic dysregulation which contribute to the fibrinolytic dysregulation in PE patients. Material & Method: Seventy-eight patients of 18 years or older age, were included in this study through enrolment conducted in conjunction with an ongoing IRB approved project by the pulmonary embolism response team (PERT) registry. Diagnosis of PE was confirmed by computed tomography (CT), angiography or ventilation perfusion imaging. Blood samples were drawn with in 24 hours of confirmed diagnosis of acute PE in 3.2% sodium citrate tubes at the time of diagnosis, processed for platelet poor plasma and frozen. Control plasma samples were obtained from 50 healthy individuals. Both the patient and control plasma samples were analyzed for D-Dimer, PAI-1 antigen, tPA, TAFI-a, protein C, alpha-2 antiplasmin, microparticles and vWF using ELISA methods (Hypen Biomedical, Franklin, Ohio). A functional PAI-1 chromogenic substrate method and an ELISA based uPA antigen method was used (Biomedica, Halifax, Nova Scotia, Canada). Circulating levels of each of the individual biomarkers were compared to normal plasma, descriptive statistics including non-parametric Mann-Whitney t-test and spearman correlation coefficient analysis was carried out by using GraphPad Prism software. Percent Increase from the normal mean was calculated for each individual parameter. p value <0.05 was considered statistically significant. Result: In comparison to normal group, the PE patients exhibited varying levels of increase in the D-Dimer, tPA, uPA, PAI-1 antigen, PAI-1 functional, TAFI antigen, microparticles and vWF, whereas decreased levels were noted for protein C and alpha-2 antiplasmin as shown on Figure 1. D-Dimer showed the most pronounced increase (368.2-fold) followed by tPA (165.9-fold), PAI-1 antigen (3.91-fold), microparticles (2.14-fold), vWF (1.83-fold), uPA (0.5-fold), TAFI antigen (0.40-fold) and PAI-1 functional (0.34-fold). In correlation analysis, D-Dimer negatively correlated with TAFI antigen (r= -0.3106) and alpha-2 antiplasmin (r= -0.3056), functional PAI-1 levels positively correlated with tPA (r= 0.3117) and protein C (r= 0.4059), tPA negatively correlated with TAFI antigen (r= -0.4601), alpha-2 antiplasmin (r= -0.2460) and positively correlated with microparticles (r= 0.2456) , TAFI antigen positively correlated with protein C (r= 0.3612), alpha-2 antiplasmin (r= 0.3899) and negatively correlated with microparticles (r= -0.2470) whereas protein C showed a negative correlation with vWF (r= -0.2838). Conclusion: The markedly increased D-Dimer levels suggest increase clot burden in PE patients. tPA antigen is also markedly increased, whereas the uPA showed modest increase which may suggest compensatory upregulation, PAI-1 antigen levels were much higher in comparison to PAI-1 functional activity, suggesting consumption of this inhibitor. Decreased alpha-2 antiplasmin and protein C levels also suggest consumption. Increased TAFI antigen contribute to the clot resistant to fibrinolysis. Cellular consumption and endothelial dysfunction results in increased in vWF and microparticles promoting thrombogenesis. Measurement of these biomarkers may be useful in the understanding of the pathogenesis, risk stratification and clinical management of PE patients. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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Biomarkers of Hemostatic Activation and Inflammation Are Associated with Altered Coagulation Parameters in Sepsis Patients

Blood ◽

10.1182/blood-2019-130420 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2401-2401

Author(s):

Emily Bontekoe ◽

Matthew T. Rondina ◽

Debra Hoppensteadt ◽

Elizabeth Middleton ◽

Antoinette Blair ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Inflammatory Response ◽

Sepsis Group ◽

P Value ◽

Plasma Samples ◽

Pronounced Increase ◽

Coagulation Parameters ◽

Simultaneous Activation ◽

Pai 1 ◽

D Dimer

Background : Sepsis is characterized by a simultaneous activation of inflammation and hemostasis in response to microbial infection. This systemic inflammatory response is due to the release of pro-inflammatory cytokines, pro-coagulants and adhesion molecules from immune cells and/or damaged endothelial tissue. Simultaneous activation of coagulation and fibrinolysis leads to consumption coagulopathy and severe vascular dysfunction. Profiling of biomarkers of hemostatic activation and inflammation along with the measurement of coagulation parameters has provided useful data in the understanding of the pathogenesis of sepsis. This study was designed to profile biomarkers of hemostatic activation, inflammation and endothelial dysfunction along with the measurement of coagulation parameters in a defined clinically confirmed sepsis population in conjunction with an IRB approved clinical trial. Materials & Methods: Citrated blood samples were collected from sepsis patients with suspected or confirmed infection, and organ dysfunction as defined by a SOFA ³ baseline. Plasma samples from septic shock patients were collected in citrated tubes within 72 hours of ICU admission under an IRB approved protocol in conjunction with an ongoing trial at the University of Utah and Veteran's Affair FFC Health Care System VAMC. Normal controls were comprised of commercially available 25 male and 25 female citrated plasma samples (George King Biomedical, Overland Park, Kansas City). Such biomarkers as CRP, PAI-1, D-Dimer, vWF and microparticle tissue factor complex (MP-TF) were measured using a commercially available sandwich ELISA methods. Nitric oxide (NO) levels were measured using a commercially available Griess reaction based colorimetric method. PT/INR, aPTT and fibrinogen measurements were based on clot based assays. All results were compiled as mean ± SD and SEM. Correlation analysis was carried out to determine relevance between different parameters. Results: Most of the biomarkers of hemostatic activation and inflammation were elevated in patients with sepsis as shown on table 1a, CRP (66 fold) and D-Dimer (23 fold) showed the most pronounced increase in comparison to the control. Other parameters also showed increase levels including MP-TF (5.3 fold), PAI-1 (3.5 fold), vWF (3.1 fold) and NO (3.0 fold). Clotting parameters such as PT/INR (2.0 fold), aPTT (2.5 fold) and fibrinogen (2.0 fold) were also significantly elevated in the sepsis patients. These differences were significant (p value ≤0.0009) for all of the parameters except for NO (p value 0.0937) and fibrinogen (p value 0.4694). As shown on table 1b, there was no correlation between various biomarkers and fibrinogen in the sepsis patients. Summary & Conclusion: In comparison to the control group, the sepsis patients showed wide variations in all of the parameters investigated in this study. The marked prolongation of PT and aPTT are suggestive of both the extrinsic and intrinsic pathway defects and consumption of clotting factors. The aPTT data showed wider scatter in comparison to PT data. The fibrinogen levels were also elevated and nearly 1/3 of the patients showed >1000 mg/dL levels. The markedly higher level of CRP in the sepsis group are indicative of severe inflammatory response. Marked elevation of D-Dimer is indicative of endogenous fibrin formation and its consumption consistent with activation of secondary fibrinolysis. MP-TF, vWF and PAI-1 were also increased in the sepsis patients suggesting marked endothelial dysfunction. This is consistent with increased NO levels which may be due to induction of iNOS in the endothelial lining of sepsis patients. These results further underscore the multifactorial pathophysiology of sepsis which results in the dysregulation of hemostasis, upregulation of inflammatory responses and generalized endothelialopathy. Profiling of the biomarkers included in this study and coagulation parameters may be helpful in the risk stratification and clinical management of patients with sepsis and related disorders. Disclosures No relevant conflicts of interest to declare.

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A Comparative Analysis of D-Dimer Assays in Patients with Clinically Suspected Pulmonary Embolism

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649595 ◽

1993 ◽

Vol 70 (03) ◽

pp. 408-413 ◽

Cited By ~ 43

Author(s):

Edwin J R van Beek ◽

Bram van den Ende ◽

René J Berckmans ◽

Yvonne T van der Heide ◽

Dees P M Brandjes ◽

...

Keyword(s):

Pulmonary Embolism ◽

Comparative Analysis ◽

High Probability ◽

Pulmonary Emboli ◽

Plasma Samples ◽

Suspected Pulmonary Embolism ◽

Lung Scan ◽

D Dimer

SummaryTo avoid angiography in patients with clinically suspected pulmonary embolism and non-diagnostic lung scan results, the use of D-dimer has been advocated. We assessed plasma samples of 151 consecutive patients with clinically suspected pulmonary embolism. Lung scan results were: normal (43), high probability (48) and non-diagnostic (60; angiography performed in 43; 12 pulmonary emboli). Reproducibility, cut-off values, specificity, and percentage of patients in whom angiography could be avoided (with sensitivity 100%) were determined for two latex and four ELISA assays.The latex methods (cut-off 500 μg/1) agreed with corresponding ELISA tests in 83% (15% normal latex, abnormal ELISA) and 81% (7% normal latex, abnormal ELISA). ELISA methods showed considerable within- (2–17%) and between-assay Variation (12–26%). Cut-off values were 25 μg/l (Behring), 50 μg/l (Agen), 300 μg/l (Stago) and 550 μg/l (Organon). Specificity was 14–38%; in 4–15% of patients angiography could be avoided.We conclude that latex D-dimer assays appear not useful, whereas ELISA methods may be of limited value in the exclusion of pulmonary embolism.

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Pulmonary Vessel Obstruction Does Not Correlate with Severity of Pulmonary Embolism

Journal of Clinical Medicine ◽

10.3390/jcm8050584 ◽

2019 ◽

Vol 8 (5) ◽

pp. 584 ◽

Cited By ~ 2

Author(s):

Marianne Lerche ◽

Nikolaos Bailis ◽

Mideia Akritidou ◽

Hans Jonas Meyer ◽

Alexey Surov

Keyword(s):

Pulmonary Embolism ◽

Statistical Significance ◽

Pulmonary Arteries ◽

Severity Index ◽

Clinical Severity ◽

Pulmonary Vessel ◽

Wells Score ◽

Clot Burden ◽

Spearman’S Correlation ◽

D Dimer

The aim of the present study was to analyze possible relationships between pulmonary vessel obstruction and clinically relevant parameters and scores in patients with pulmonary embolism (PE). Overall, 246 patients (48.8% women and 51.2% men) with a mean age of 64.0 ± 17.1 years were involved in the retrospective study. The following clinical scores were calculated in the patients: Wells score, Geneva score, and pulmonary embolism severity index (PESI) score. Levels of D-dimer (µg/mL), lactate, pH, troponin, and N-terminal natriuretic peptide (BNP, pg/mL) were acquired. Thrombotic obstruction of the pulmonary arteries was quantified according to Mastora score. The data collected were evaluated by means of descriptive statistics. Spearman’s correlation coefficient was used to analyze associations between the investigated parameters. P values < 0.05 were taken to indicate statistical significance. Mastora score correlated weakly with lactate level and tended to correlate with D-dimer and BNP levels. No other clinical or serological parameters correlated significantly with clot burden. Thrombotic obstruction of pulmonary vessels did not correlate with clinical severity of PE.

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The Value of D-Dimer in Patients with Increased C-Reactive Protein Suspected of Pulmonary Embolism.

Blood ◽

10.1182/blood.v114.22.5056.5056 ◽

2009 ◽

Vol 114 (22) ◽

pp. 5056-5056

Author(s):

Claire Siemes ◽

Paul Berendes ◽

Frans van der Straaten ◽

Ton Cleophas ◽

Mark-David Levin

Keyword(s):

Pulmonary Embolism ◽

Conflicts Of Interest ◽

Area Under The Curve ◽

Roc Curves ◽

Serum Levels ◽

C Reactive Protein ◽

Reactive Protein ◽

Interaction Term ◽

Pulmonary Embolisms ◽

D Dimer

Abstract Abstract 5056 OBJECTIVE To investigate the relation between elevated levels of C-reactive protein (CRP) and D-dimer, and to study whether D-dimer levels can be interpreted in relation to elevated levels of CRP in the prediction of a pulmonary embolism in order to increase its specificity without decline in sensitivity. METHODS Between august 2004 and april 2007 (33 months) serum levels of C-reactive protein (mmol/L) and D-dimer (mmol/L) were cross-sectionally collected and pulmonary embolisms on CT-angiograms were scored within 48 hours. The study was devided into three parts. First, characteristics of excluded persons were studied. Second, the correlation between CRP and D-dimer level was considered in those with a defined (i.e. values with < and > symbols excluded) biomarker level. Finally, the effect of CRP level on the sensitivity of D-dimer for pulmonary embolisms was examined. RESULTS CRP and D-dimer levels were positively correlated ( r = 0.37; p < 0.001), and both were increased in persons with a pulmonary embolism (CRP: p = 0.02; D-dimer: p < 0.001). 14 % of variability in D-dimer level was explained by CRP level. Median D-dimer levels were increased in the pulmonary embolism (PE) group, however, the increase in D-dimer level by CRP quartile as was found in the non-PE was not seen in de PE-group. Adding the interaction term of CRP and D-dimer to the statistical model showed some influence on the area under the curve (AUC). Nevertheless, this was not significantly different from the model with only D-dimer levels. However, when stratified for CRP quartile, ROC-curves of the predictive effect of D-dimer on pulmonary embolisms showed a decrease in AUC by increment of CRP quartile. CONCLUSION CRP and D-dimer are positively correlated, and both predictive of PE. The predictive value of D-dimer for PE declines by increment of CRP, although this seems to be safely for a broader range of accompanied CRP levels. Disclosures No relevant conflicts of interest to declare.

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Relationship of Markers of Inflammation, Infection and Endothelial Function to Mortality and Severity of Coagulopathy in Patients with Sepsis-Associated DIC

Blood ◽

10.1182/blood-2018-99-115302 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2495-2495

Author(s):

Debra Hoppensteadt ◽

Amanda Walborn ◽

Matthew T. Rondina ◽

Jawed Fareed

Keyword(s):

Endothelial Function ◽

Protein C ◽

Conflicts Of Interest ◽

Interleukin 10 ◽

Response To Treatment ◽

Necrosis Factor Alpha ◽

Multiple Systems ◽

Markers Of Inflammation ◽

Prediction Of Mortality ◽

Pai 1

Abstract Background: Sepsis-associated disseminated intravascular coagulation (DIC) is a complex clinical scenario involving derangement of many processes, including hemostasis. Assessment of markers of these other aspects of disease, including inflammation, immunity, endothelial function, and endogenous anticoagulants may provide insight into DIC pathophysiology and lead to improved methods for assessment of patient condition and response to treatment. This study was designed to measure biomarkers representative of multiple systems involved in DIC development in a cohort of patients with sepsis and DIC and determine the association of these biomarkers with disease severity and mortality. Materials and Methods: Citrated plasma samples were prospectively collected from 102 patients with sepsis and suspected DIC at ICU admission (day 0) and again serially on ICU days 4 and 8 under an IRB approved protocol. DIC score was determined using the ISTH scoring algorithm (e.g. platelet count, PT/INR, fibrinogen, and D-Dimer). Plasma from healthy individuals was purchased from a commercial laboratory (George King Biomedical, Overland, KS). . CD 40 Ligand (CD40L), Plasminogen inhibitor 1 ( PAI-1), nucleosomes, Procalcitonun (PCT), Microparicle Tissue Factor (MP-TF), and Prothrombin Fragment 1.2 (F1.2) were measured using commercially available ELISA kits. Protein C activity was measured using a clot-based assay. Interleukin 6 (IL-6), Interleukin 8 (IL-8), Interleukin 10 (IL-10) , Tumor Necrosis Factor Alpha (TNFα) , Monocyte Chemoattractant protein 1 (MCP-1) were measured using a biochip technology. Results: Significant differences in levels of Protein C (p=0.009), PCT (p=0.0005), IL-6 (p=0.019), IL-8 (p= 0.015), and PAI-1 (p=0.015) were observed between survivors and non-survivors (Table 1). Significant variation of Protein C (p=0.002), nucleosomes (p=0.05), PCT (P<0.001), IL-6 (p=0.001), IL-8 (p=0.003), IL-10 (p=0.011), TNFα (p=0.021), and MCP-1 (p=0.21), were observed based on severity of DIC score. Conclusion: Markers from multiple systems perturbed in DIC were associated with mortality suggesting that while these systems may not be routinely evaluated in the course of patient care, dysfunction of these system contribute significantly to mortality. In addition, numerous inflammatory cytokines showed an association with DIC score. This study suggests that the measurement of additional markers in sepsis-associated DIC may be of value in the prediction of mortality and may be helpful in guiding treatment for these patients. Disclosures No relevant conflicts of interest to declare.

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Dysregulation of Hemostatic Biomarkers, Inflammatory Biomarkers, and Alteration of Cellular Indices As Predictors of Adverse Outcomes in Pulmonary Embolism Patients

Blood ◽

10.1182/blood-2019-126876 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2408-2408

Author(s):

Iman Darwish ◽

Yevgeniy Brailovsky ◽

Amir Darki ◽

Debra Hoppensteadt ◽

Brett Slajus ◽

...

Keyword(s):

Pulmonary Embolism ◽

Patient Outcomes ◽

White Cell ◽

Inflammatory Biomarkers ◽

Positive Trend ◽

Pronounced Increase ◽

Lymphocyte Ratio ◽

Cell Counts ◽

All Cause Mortality ◽

D Dimer

Background: Pulmonary Embolism (PE) is a condition that affects a multitude of individuals worldwide. The pathophysiology of PE is multifactorial and complex. Measuring levels of biomarkers in PE patient plasma may be predictive of patient outcomes in terms of survival, and such biomarkers could be correlated to other parameters such as white cell counts and their ratios. Adhesion molecules, such as selectins, have been predicted to play a role in the pathophysiology of PE, however their relationship to other cellular parameters is not fully explored. P-selectin is found on platelets, and is involved in the gathering of platelets in thrombotic states. Meanwhile, E and L-selectin contribute to cellular rolling that occurs in states of inflammation. White blood cell counts are routinely obtained from patient blood analysis. Selectins, including Platelet (P), Endothelial (E), and Leukocyte (L) Selectins may possess relationships to the white cell profiles including neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), platelet-neutrophil ratio (PNR), lymphocyte-monocyte ratio (LMR), and monocyte-neutrophil ratio (MNR). Selectins can also be correlated to total platelet and white cell counts. Mortality outcomes in PE patients may be associated with altered levels of hemostatic and inflammatory biomarkers such as selectins. Materials and Methods: Blood samples were acquired from 100 patients diagnosed with acute PE between March 2016 and June 2019 at Loyola University Medical Center in Maywood, IL. Enzyme Linked Immunosorbent Assays (ELISA) were used to quantify levels of P, E, and L selectins in the plasma of PE patients. Other coagulation and inflammatory biomarkers, including Tumor Necrosis Factor Alpha (TNFa), D-dimer, Plasminogen Activating Inhibitor-1 (PAI-1), Matrix Metalloprotease-9 (MMP-9), C-Reactive Protein (CRP), micro particles, and alpha-2-antiplasmin were also quantified. Patient chart review was conducted assessing for levels of platelets, neutrophils, lymphocytes, and monocytes. Appropriate cellular ratios were calculated. Patient outcomes in the form of mortality were noted. Spearman non-parametric analysis and Wilcoxon-Mann-Whitney Tests were conducted using Graphpad PRISM software. Results: All of the biomarkers studied exhibited an increase in PE patient plasma, ranging from 2 fold to 34.6 fold increase, with the exception of alpha-2-antiplasmin, E-selectin, and L-selectin, as shown in Table 1. D-dimer, MMP-9, and CRP show the most pronounced increase in PE patients. No statistically significant correlations were noted between P, E, and L-selectins and NLR, PLR, PNR, LMR, or MNR. P-selectin was positively correlated with platelet count (r=.22, p=.032, 95% CI=0.01293 to 0.4084, n=95). L-selectin was not found to be significantly correlated with white count, but a positive trend was still evident (r=.13, p=.22, CI= -0.08329 to 0.3250, n=95). Within the patient pool, 12% of patients were deceased, while 88% survived. L-selectin and all-cause mortality were significantly correlated at an alpha level of .05 (p=.04). Conclusion: These studies demonstrate the marked dysregulation of hemostatic and inflammatory biomarkers associated with alterations of cellular indices. In particular, P and L selectin demonstrated some relationship to platelets and white count. L-selectin levels are significantly correlated to all-cause mortality. Measuring levels of L-selectin in PE patients may provide insight into mortality outcomes for pulmonary embolism patients. Our results are suggestive of the positive predictive value of L-selectin in PE patients. Profiling of various biomarkers, in particular selectins, may be helpful in the risk stratification of PE patients. Adding such a parameter to patient analysis may provide better prognostic information, which may be helpful in their clinical management. Disclosures No relevant conflicts of interest to declare.

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STUDY OF THE PLASMA COMPONENT OF THE BLOOD AGGREGATION REGULATORY SYSTEM IN SUBJECTS IN THE EXPERIIMENT WITH 120-DAY ISOLATION INSIDE PRESSURIZED MODULE SIRIUS-19

Aerospace and Environmental Medicine ◽

10.21687/0233-528x-2021-55-1-59-62 ◽

2021 ◽

Vol 55 (1) ◽

pp. 59-62

Author(s):

D.S. Kuzichkin ◽

◽

А.А. Markin ◽

О.А. Zhuravleva ◽

Z.А. Krivitsina ◽

...

Keyword(s):

Protein C ◽

Antithrombin Iii ◽

Regulatory System ◽

Activated Partial Thromboplastin Time ◽

Thrombin Time ◽

Plasma Samples ◽

Plasma Component ◽

Aggregation Parameters ◽

Aggregation Control ◽

D Dimer

Citrate plasma samples gathered 31 days prior to, on days 37, 63, 120 in and on days 7 and 14 after isolation (project Sirius-19) were analyzed for blood aggregation parameters including fibrinogen (FBG), D-dimer (DD), plasminogen (PG), antithrombin III (АТ3), protein C (PC) and α2-antiplasmin (AP), thrombin time (TT), activated partial thromboplastin time (APTT), and prothrombin time (PT). DD was lowered in all samples gathered during isolation. The complex of isolation factors combined with physical exercise reduced levels of fibrin formation and fibrinolysis. However, after isolation the procoagulent activity showed an increase manifested by elevated DD and reduced APTT. Appears that in the absence of insertion and reentry effects (redistribution of body fluids in microgravity) and high psychophysiological stresses it is the appropriate use of physical countermeasures that ensures plasma efficiency within the blood aggregation control system, and good body tolerance of the spaceflight factors.

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Ex vivo effects of low-dose rivaroxaban on specific coagulation assays and coagulation factor activities in patients under real life conditions

Thrombosis and Haemostasis ◽

10.1160/th12-04-0228 ◽

2013 ◽

Vol 109 (01) ◽

pp. 127-136 ◽

Cited By ~ 41

Author(s):

Christian Hesse ◽

Gertrud Stratmann ◽

Edelgard Lindhoff-Last ◽

Helen Mani

Keyword(s):

Protein C ◽

Low Dose ◽

Ex Vivo ◽

Coagulation Factor ◽

Protein S ◽

Plasma Samples ◽

Lupus Anticoagulants ◽

Coagulation Assays ◽

Administration Time ◽

D Dimer

SummaryGlobal coagulation assays display variable effects at different concentrations of rivaroxaban. The aim of this study is to quantify the ex vivo effects of low-dose rivaroxaban on thrombophilia screening assays and coagulation factor activities based on the administration time, and to show how to mask possible interferences. Plasma samples from 40 patients receiving rivaroxaban 10 mg daily were investigated to measure activities of clotting factor II, V, VII, VIII, IX, XI, XII and XIII; protein C- and protein S-levels; lupus anticoagulants; anticardiolipin IgG and IgM; D-dimer, heparin-platelet factor 4 (HPF4) antibodies and screening tests for von Willebrand disease (VWD). Two hours after rivaroxaban administration, the activities of clotting factors were significantly decreased to different extents, except for factor XIII. Dilution of plasma samples resulted in neutralisation of these interferences. The chromogenic protein C activity assay was not affected by rivaroxaban. Depending on the timing of tablet intake in relation to blood sampling protein S activity was measured falsely high when a clotting assay was used. False-positive results for lupus anticoagulants were observed depending on the assay system used and the administration time of rivaroxaban. ELISA-based assays such as anticardiolipin IgG and IgM, D-dimer, HPF4-antibodies and the turbidimetric assays for VWD were not affected by rivaroxaban. Specific haemostasis clotting tests should be performed directly prior to rivaroxaban intake. Assay optimisation in the presence of rivaroxaban can be achieved by plasma dilution. Immunologic assays are not influenced by rivaroxaban, while chromogenic assays can be used, when they do not depend on factor Xa.

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D-Dimer As a Prognostic Biomarker for Venous Thromboembolism after Hematopoietic Cell Transplantation

Blood ◽

10.1182/blood-2019-127862 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3645-3645

Author(s):

Ang Li ◽

Qian Vicky Wu ◽

Gary Schoch ◽

Madeline Kesten ◽

Emily Pao ◽

...

Keyword(s):

Cohort Study ◽

Venous Thromboembolism ◽

Prognostic Biomarker ◽

Clinical Suspicion ◽

Plasma Samples ◽

Post Transplant ◽

C Statistic ◽

History Of ◽

Pai 1 ◽

D Dimer

Introduction: D-dimer has been well characterized as a prognostic biomarker for venous thromboembolism (VTE) in both the general population and cancer patients. However, it is unclear if D-dimer has prognostic value after hematopoietic transplantation (HCT) in the context of regimen-related toxicity, immune dysregulation, and infectious complications. In the current study, we examined the utility of biomarkers of coagulation activation and fibrinolysis (D-dimer, PAI-1, and TPA) as prognostic and diagnostic biomarkers for VTE post-transplant. Methods: We performed a prospective cohort study of adult allogeneic or autologous HCT recipients over 4 years at the Fred Hutchinson Cancer Research Center. Plasma samples were collected weekly from pre-transplant to discharge from HCT. Plasma samples were rapidly thawed and concentrations of D-dimer, PAI-1 activity, and TPA antigens were tested by commercially available immunoassays. VTE was defined as radiology confirmed pulmonary embolism (PE), lower extremity (LE) or upper extremity (UE) deep vein thrombosis (DVT) within 1 year after the date of transplant. This outcome was abstracted through a combination of ICD codes and individual patient record review. Cumulative incidence was estimated using the Kaplan Meier failure method. We used the Cox regression model to determine the association between baseline biomarkers and the development of VTE. The prediction accuracy of the model was assessed by the Harrell's C statistic. To explore the utility of D-dimer testing post-transplant, we selected all patients that had clinical suspicion for VTE, underwent radiographic evaluation (chest computed tomography or compression ultrasound), and had available sample for D-dimer testing within a two-week window. We defined the age-adjusted threshold as 500 ng/mL if at or below age 50 and 10 times the age if above age 50. We also repeated the analysis using a higher cut-off of 1000 ng/mL. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were generated from the 2x2 table. Results: We identified 112 HCT adult recipients (97 allogeneic and 15 autologous) who were enrolled in the prospective cohort study and provided baseline plasma samples for biomarker testing. Patients had a mean age of 48, were predominately male and white, and had acute myeloid leukemia (AML) as the most common diagnosis (Table 1). Approximately 8% (9 patients) had a history of prior VTE. During the 1-year follow-up period, a total of 8 patients developed VTE (3 PE, 3 LE-DVT, 2 UE-DVT) with a cumulative incidence of 11.8% (5.8-23.2) by 12 months. There was no association between baseline TPA and PAI-1 and VTE; however, baseline D-dimer was associated with VTE with a HR of 1.91 (p=0.007) in the unadjusted model and a HR of 1.95 (p=0.007) in the model adjusted for history of VTE (Table 2). The predictive model with baseline D-dimer and history of VTE had a Harrell's C statistic of 0.75 for discrimination. For the exploratory analysis of the D-dimer post-transplant, we used a subset of 21 patients that had clinical suspicion of VTE, radiology confirmation, and available plasma sample for D-dimer testing. The sensitivity and NPV for both age-adjusted cut-off and 1000 ng/mL were 100%; however, the sample size was small (Table 3). Conclusions: In this cohort study, we found that baseline D-dimer, but not PAI-1 or TPA, was associated with the development of VTE during the first-year post-transplant. A multivariable model with D-dimer and history of VTE had a modest discrimination for VTE prediction. Similar to many clinical settings, D-dimer testing post-transplant may aid clinicians with prediction and diagnosis of VTE. Larger cohort is needed for validation of the findings. Disclosures No relevant conflicts of interest to declare.

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STUDY ON THE EFFECT OF UNFRACTIONATED (UFH) AND LOW MOLECULAR WEIGHT (LMWH) HEPARINS ON THE DETERMINATION OF PROTEIN C ACTIVITY

10.1055/s-0038-1644315 ◽

1987 ◽

Author(s):

N Sala ◽

J Fontcuberta

Keyword(s):

Protein C ◽

Plasma Samples ◽

Protamine Sulphate ◽

Vein Thrombosis ◽

Antigen Elisa ◽

Before And After ◽

Control Plasma ◽

Protein C Activity

In an attempt to see whether the presence of different heparins affected the determination of protein C activity (APC),this parameter was measured before and during treatment in 23 deep vein thrombosis patients that had been randomly treated with 3 different LMWH (Choay CY-216 and CY-222 and Kabi-2165) and UFH,for 10 days, Very low levels of APC (amidolytic assay that uses thrombin-thrombomodulin to activate the barium citrate eluted PC) were found in those patients receiving UFH and having an APTT more than 3 times that of control, as well as in those patients receiving LMWH CY-216 and having an APTT of only 8 to 10 seconds higher than that of control plasma, In patients receiving CY-222 and Kabi-2165, no significant differences were observed between APC levels before and during treatment, PC antigen (ELISA assay) was normal in all cases, In order to see if these low APC levels were due to interference of heparin with the assay and at which doses, control plasma pool was supplemented "in vitro" with 0 to 2.5 IU/ml (0 to 0,00252) of UFH and with 0 to 3 anti-Xa U/ml of LMWH CY-216, APTT, PCAg, APC and presence of ATI 11 in the barium citrate eluates (immunodiffusion), were determined in all plasma samples before and after treatment with protamine sulphate (PS) at 0,0032, The results showed that UFH, when not neutralized with PS, resulted in low APC values only at doses higher than 0,8 IU/ml, corresponding to an APTT of more than 3 times that of control plasma, LMWH CY-216 at doses above 1 anti-XaU/ml, corresponding to an APTT of only 10 seconds higher than that of control, also produced a gradual decrease in APC values, ATI 11 was clearly visualized in the barium citrate eluates of all those plasma samples having a low APC value, The addition of PS to all samples containing UFH resulted in a complete normalization of APC values, with almost normal AFTT values and disappearance of ATI 11 from the barium citrate eluates, On the contrary, addition of PS to plasma containing CY-216 resulted in low APC values and presence of ATI 11 in the eluates of those samples containing more than 4 antiXaU/ml, whose APTT still was about 10 seconds above that of control.It is concluded that at therapeutic doses not only UFH but also LMWH CY-216 interfere with the APC assay, probably through binding of hepar in-ATI 11 complexes to barium citrate and neutralization of the thrombin used to activate the barium citrate eluted PC, LMWH CY-222 and Kabi-2165, although increasing the APTT similarly to CY-216, do not seem to interfere with the APC assay, Protamine sulphate, at 0,0032 in plasma, completely abolishes the effect of UFH on APC assay but not that of LMWH CY-216, More studies are being performed to see if higher doses of PS can be used to neutralize the effect of this LMWH.

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