Prothrombin conversion and thrombin decay in patients with cirrhosis-role of prothrombin and antithrombin deficiencies.

BACKGROUND: Thrombin generation (TG) in the presence of thrombomodulin (TG-TM) in the plasma of patients with cirrhosis (PWC) is tilted toward a hypercoagulable phenotype. Low protein C and elevated factor VIII levels play a role, but other determinants, such as the prothrombin/antithrombin pair, must also be studied. OBJECTIVES: The objectives were (i) to quantitatively assess the subprocesses (prothrombin conversion and thrombin decay) and (ii) to understand the underlying mechanism by studying TG dynamics after prothrombin and antithrombin plasma level correction in PWC. METHODS: We studied TG-TM in plasma samples of 36 healthy controls (HCs) and 41 PWC with prothrombin and antithrombin levels of <70% and after their correction. We initiated coagulation with an intermediate picomolar concentration of tissue factor. We determined the overall thrombin potential, prothrombin conversion, and thrombin decay. RESULTS: TG-TM was increased in PWC compared with HC due to impaired thrombin inhibition. Indeed, thrombin decay capacity (min-1) decreased from 0.37 (0.35-0.40) in HC to 0.33 (0.30-0.37) in the Child-Turcotte-Pugh A (CTP-A; P = .09), 0.27 (0.26-0.30) in the CTP-B (P < .001), and 0.20 (0.19-0.20) in the CTP-C (P < .001) group. Concomitant correction of prothrombin and antithrombin increased endogenous thrombin potential with prothrombin conversion surpassing thrombin decay. By contrast, when we corrected only antithrombin, TG-TM was normalized and even consistent with a hypocoagulable phenotype in the CTP-C group. CONCLUSION: Our results highlight that in PWC, hypercoagulability (evidenced in the presence of TM) is due to impaired thrombin decay, whereas low prothrombin levels do not translate into decreased prothrombin conversion, likely due to altered TM-activated protein C negative feedback.

Antithrombin Levels and Heparin Responsiveness during Venoarterial Extracorporeal Membrane Oxygenation: A Prospective Single-center Cohort Study.

BACKGROUND: Unfractionated heparin, administered during venoarterial extracorporeal membrane oxygenation to prevent thromboembolic events, largely depends on plasma antithrombin for its antithrombotic effects. Decreased heparin responsiveness seems frequent on extracorporeal membrane oxygenation; however, its association with acquired antithrombin deficiency is poorly understood. The objective of this study was to describe longitudinal changes in plasma antithrombin levels during extracorporeal membrane oxygenation support and evaluate the association between antithrombin levels and heparin responsiveness. The hypothesis was that extracorporeal membrane oxygenation support would be associated with acquired antithrombin deficiency and related decreased heparin responsiveness. METHODS: Adults receiving venoarterial extracorporeal membrane oxygenation were prospectively included. All patients received continuous intravenous unfractionated heparin using a standardized protocol (target anti-Xa 0.3 to 0.5 IU/ml). For each patient, arterial blood was withdrawn into citrate-containing tubes at 11 time points (from hour 0 up to day 7). Anti-Xa (without dextran or antithrombin added) and antithrombin levels were measured. The primary outcome was the antithrombin plasma level. In the absence of consensus, antithrombin deficiency was defined as a time-weighted average of antithrombin less than or equal to 70%. Data regarding clinical management and heparin dosage were collected. RESULTS: Fifty patients, including 42% postcardiotomy, were included between April 2020 and May 2021, with a total of 447 samples. Median extracorporeal membrane oxygenation duration was 7 (interquartile range, 4 to 12) days. Median antithrombin level was 48% (37 to 60%) at baseline. Antithrombin levels significantly increased throughout the follow-up. Time-weighted average of antithrombin levels was 63% (57 to 73%) and was less than or equal to 70% in 32 (64%) of patients. Overall, 45 (90%) patients had at least one antithrombin value less than 70%, and 35 (70%) had at least one antithrombin value less than 50%. Antithrombin levels were not significantly associated with heparin responsiveness evaluated by anti-Xa assay or heparin dosage. CONCLUSIONS: Venoarterial extracorporeal membrane oxygenation support was associated with a moderate acquired antithrombin deficiency, mainly during the first 72 h, that did not correlate with heparin responsiveness.

Increased risk of dialysis circuit clotting in hemodialysis patients with COVID-19 is associated with elevated FVIII, fibrinogen and D-dimers.

INTRODUCTION: Severe COVID-19 infections increase the risk of thrombotic events and Intensive Care Units reported increased extracorporeal circuit clotting (ECC) in COVID-19 patients with acute kidney injury. We wished to determine whether hemodialysis (HD) patients with COVID-19 also have increased risk of circuit clotting. METHODS: We reviewed coagulation studies and HD records, 4 weeks before and after COVID-19 polymerase chain reaction detection in HD patients between April 2020 and June 2021. FINDINGS: Sixty-eight (33.5%) of 203 HD patients with COVID-19, 65% male, mean age 64.9 ± 15.3 years, experienced some circuit clotting, and no clotting recorded prior to positive test results. In those who experienced ECC, prothrombin, activated partial thromboplastin or thrombin times were not different, whereas median factor VIII (273 [168-419] vs. 166 [139-225] IU/dl, p < 0.001), D-dimers (2654 [1381-6019] vs. 1351 [786-2334] ng/ml, p < 0.05), and fibrinogen (5.6 ± 1.4 vs. 4.9 ± 1.4 g/L, p < 0.05) were greater. Antithrombin (94 [83-112] vs. 89 [84-103] IU/dl), protein C (102 [80-130] vs. 86 [76-106] IU/dl), protein S (65 [61-75] vs. 65 [52-79] IU/dl) and platelet counts (193 [138-243] vs. 174 [138-229] × 109 /L) did not differ. On multivariable logistic analysis, circuit clotting was associated with log factor VIII (odds ratio [OR] 14.8 (95% confidence limits [95% CL] 1.12-19.6), p = 0.041), fibrinogen (OR 1.57 [95% CL 1.14-21.7], p = 0.006) and log D dimer (OR 4.8 [95% CL 1.16-12.5], p = 0.028). DISCUSSION: Extracorporeal circuit clotting was increased within 4 weeks of testing positive for COVID-19. Clotting was associated with increased factor VIII, fibrinogen and D-dimer, suggesting that the risk of circuit clotting was related to the inflammatory response to COVID-19.

Factor VIIa-AT Complex Is an Independent Prognostic Marker of Disseminated Intravascular Coagulation.

OBJECTIVE: The factor VIIa-Antithrombin (VIIa-AT) complex is a relatively new biomarker associated with the activation of the extrinsic coagulation pathway. Since disseminated intravascular coagulation (DIC) is primarily driven by issue factor (TF)-induced extrinsic coagulation activation, the plasma level of factor VIIa-AT, via its role as an activation marker of the extrinsic pathway, could be a potential marker for DIC. The clinical significance of extrinsic coagulation markers, including factor VIIa-AT, in DIC was investigated. METHODS: The extrinsic coagulation markers, including factor VIIa-AT, TF, factor VII, and antithrombin (AT), were measured in 148 patients clinically suspicious for DIC. Multiple linear regression and Cox proportional-hazard analysis were conducted to evaluate both contributing factors and the prognostic power of the markers. RESULTS: The factor VIIa-AT complex, factor VII, and AT levels were significantly lower in the overt-DIC group and gradually decreased according to the severity of DIC based on the DIC scores. On the contrary, TF was significantly higher in the overt-DIC group. The factor VII level was revealed as a significant independent contributor to the factor VIIa-AT level. Upon multivariable Cox proportional-hazard analysis, the factor VIIa-AT complex showed the highest hazard ratio (3.41; 95% confidence interval 1.11-10.44). CONCLUSION: The factor VIIa-AT complex reflects the severity of DIC and is an independent prognostic factor of DIC. Our findings hint at the potential of the factor VIIa-AT complex to be used as a complementary marker to well-established biomarkers such as AT.

Direct Oral Anticoagulants Plasma Levels in Patients with Atrial Fibrillation at the Time of Bleeding: A Pilot Prospective Study.

ABSTRACT: Patients with atrial fibrillation (AF) on long-term direct oral anticoagulants (DOACs) may be at higher risk of bleeding because of higher anti-Xa or anti-IIa levels. However, there is no postmarketing study investigating these DOAC plasma levels at the time of bleeding. The aim of this study was to evaluate DOAC levels at the time of a bleeding emergency. We analyzed 5440 patients examined at our Emergency Department in from April 1, 2019, to September 30, 2019. During this period, we prospective identified 105 consecutive patients with bleeding while on long-term antithrombotic therapy; 49 patients had AF on DOACs. We compared DOAC levels in patients who bled against a control sample of 55 patients who tolerated long-term high dose DOAC therapy without any emergency. Samples of these patients were tested with drug-specific anti-Xa chromogenic analysis (rivaroxaban and apixaban) and with Hemoclot Thrombin Inhibitor assay (dabigatran). Dabigatran-treated patients who bled had significantly higher anti-IIa levels when compared with trough (261.4 ± 163.7 vs. 85.4 ± 57.2 ng/mL, P < 0.001) and peak samples of controls (261.4 ± 163.7 vs. 138.8 ± 78.7 ng/mL, P < 0.05). Similarly, there were significantly higher anti-Xa levels in rivaroxaban-treated and apixaban-treated patients with bleeding compared with trough control samples (rivaroxaban: 245.9 ± 150.2 vs. 52.5 ± 36.4 ng/mL, P <0.001 and apixaban: 311.8 ± 142.5 vs. 119.9 ± 81.7 ng/mL, P < 0.001), as well as in apixaban-treated patients when compared with peak control samples (311.8 ± 142.5 vs. 210.9 ± 88.7 ng/mL, P < 0.05). Finally, rivaroxaban anti-Xa levels in patients who bled tended to be higher compared with peak control samples (245.9 ± 150.2 vs. 177.6 ± 38.6 ng/mL, P = 0.13). This observational study showed a significant difference in anti-IIa and anti-Xa plasma levels in patients with AF with bleeding complications compared with those who tolerated long-term high-dose DOAC therapy without bleeding complications.

Combination of serum paraoxonase/arylesterase 1 and antithrombin-III is a promising non-invasion biomarker for discrimination of AFP-negative HCC versus liver cirrhosis patients.

OBJECTIVE: α-fetoprotein is often used in the diagnosis of hepatocellular carcinoma (HCC). However, there are currently less efficient and highly specific biomarkers to distinguish AFP-negative HCC from liver cirrhosis (LC) patients. PATIENTS AND METHODS: We retrospectively analyzed the data of patients who were treated in our hospitals. iTRAQ coupled with mass spectrometry was used to identify candidate serum proteins in a discovery set (n = 36) including AFP-negative HCC and LC patients. After Western blot detection, potential serum biomarkers were confirmed using ELISA in a validation set (n = 90). The diagnostic performance of the selected proteins was assessed using receiver operating characteristic (ROC). RESULTS: PON1 and ATIII were selected as target proteins and were significantly higher in LC than those in AFP-negative HCC patients as validated by Western blot and ELISA, which was consistent with the result of iTRAQ. The AUC was 0.848 as PON1 and ATIII were combined (sensitivity: 80.0%; specificity: 73.3%), and performed much better than that of a single biomarker. CONCLUSION: These findings suggest that PON1 and ATIII have the potential to serve as effective biomarkers for distinguishing AFP-negative HCC from cirrhosis.

Functional Characterization of Antithrombin Mutations by Monitoring of Thrombin Inhibition Kinetics.

Inactivation of thrombin by the endogenous inhibitor antithrombin (AT) is a central mechanism in the regulation of hemostasis. This makes hereditary AT deficiency, which is caused by SERPINC1 gene mutations, a major thrombophilic risk factor. Aim of this study was to assess to what extent AT mutations impair thrombin inhibition kinetics. The study population included 36 thrombophilic patients with 19 different mutations and mean AT levels of 65% in a thrombin-based functional assay, and 26 healthy controls. To assess thrombin inhibition kinetics, thrombin (3.94 mU/mL final concentration) was added to citrated plasma. Subsequently, endogenous thrombin inhibition was stopped by addition of the reversible thrombin inhibitor argatroban and the amount of argatroban-complexed thrombin quantified using an oligonucleotide-based enzyme capture assay. The plasma half-life of human thrombin was significantly longer in patients with AT mutations than in the controls (119.9 versus 55.9 s). Moreover, it was disproportionately prolonged when compared with preparations of wild type AT in plasma, in whom a comparable thrombin half-life of 120.8 s was reached at a distinctly lower AT level of 20%. These findings may help to better understand the increased thrombotic risk of SERPINC1 mutations with near normal AT plasma levels in functional assays.

Impact of Dabigatran Treatment on Rotation Thromboelastometry.

A rapid and reliable assessment of the dabigatran effect is desirable in dabigatran treated patients with uncontrolled bleeding or before acute surgery. The aim of this study was to study the anticoagulant effects of dabigatran in patients with atrial fibrillation (AF) as assessed by the whole blood assays ROTEM, and how data from these methods correlate to plasma dabigatran concentrations measured by Hemoclot. ROTEM was performed with ROTEM Gamma (Pentapharm GmbH, Munich, Germany). The assays used in our study were Ex-tem and In-tem assay. Plasma dabigatran concentrations were determined by hemoclot thrombin inhibitor assay (Hyphen BioMed, France) at trough and post-dose in 27 patients on dabigatran 150 mg BID. Median plasma dabigatran concentrations at trough were 74 ng/mL (11.2-250) and post-dose (2 h after ingestion) 120 ng/mL (31-282). The ROTEM clotting time (CT) and maximum clot firmnes (MCF) correlated strongly with dabigatran concentrations when activated with the reagents Ex-tem (p < 0.0001) and In-tem (p < 0.0001). In summary, in our study, we have found that the ROTEM variable CT and MCF, when activated with triggers Ex-tem and In-tem, has a strong and highly significant correlation with the plasma dabigatran concentration in a real-life population of AF-patients and could thereby be an alternative to estimate dabigatran concentration in emergency situations. However, additional studies are needed to further validate these findings.

Specific Point-of-Care Testing of Coagulation in Patients Treated with Dabigatran.

BACKGROUND AND PURPOSE: Accurate and rapid assessment of coagulation status is necessary to guide thrombolysis or reversal of anticoagulation in stroke patients, but commercially available point-of-care (POC) assays are not suited for coagulation testing in patients treated with direct oral anticoagulants (DOACs). We aimed to evaluate the direct thrombin monitoring (DTM) test card by Helena Laboratories (Texas, United States) for anti-IIa-specific POC coagulation testing, hypothesizing that its POC-ecarin clotting time (POC-ECT) accurately reflects dabigatran plasma concentrations. METHODS: A prospective single-center diagnostic study (ClinicalTrials.gov-identifier: NCT02825394) was conducted enrolling patients receiving a first dose of dabigatran and patients already on dabigatran treatment. Blood samples were collected before drug intake and 0.5, 1, 2, 8, and 12 hours after intake. POC-ECT was performed using whole blood (WB), citrated blood (CB), and citrated plasma (CP). Dabigatran plasma concentrations were determined by mass spectrometry. RESULTS: In total, 240 blood samples from 40 patients contained 0 to 275 ng/mL of dabigatran. POC-ECT with WB/CB/CP ranged from 20 to 186/184/316 seconds. Pearson's correlation coefficient showed a strong correlation between dabigatran concentrations and POC-ECT with WB/CB/CP (R2 = 0.78/0.90/0.92). Dabigatran concentrations >30 and >50 ng/mL (thresholds for thrombolysis, surgery, and reversal therapy according to clinical guidelines) were detected by POC-ECT with WB/CB/CP (>36/35/45 and >43/45/59 seconds) with 95/97/97 and 96/98/97% sensitivity, and 81/87/94 and 74/60/91% specificity. CONCLUSION: This first study evaluating DOAC-specific POC coagulation testing revealed an excellent correlation of POC-ECT with actual dabigatran concentrations. Detecting clinically relevant dabigatran levels with high sensitivity/specificity, the DTM assay represents a suitable diagnostic tool in acute stroke, hemorrhage, and urgent surgery.

Prognostic Value of Antithrombin Levels in COVID-19 Patients and Impact of Fresh Frozen Plasma Treatment: A Retrospective Study

Objective: The defective interplay between coagulation and inflammation may be the leading cause of intravascular coagulation and organ dysfunction in coronavirus disease-19 (COVID-19) patients. Abnormal coagulation profiles were reported to be associated with poor outcomes. In this study, we assessed the prognostic values of antithrombin (AT) activity levels and the impact of fresh frozen plasma (FFP) treatment on outcome. Materials and Methods: Conventional coagulation parameters as well as AT activity levels and outcomes of 104 consecutive critically ill acute respiratory distress syndrome (ARDS) patients with laboratory-confirmed COVID-19 disease were retrospectively analyzed. Patients with AT activity below 75% were treated with FFP. Maximum AT activity levels achieved in those patients were recorded. Results: AT activity levels at admission were significantly lower in nonsurvivors than survivors (73% vs. 81%). The cutoff level for admission AT activity was 79% and 58% was the lowest AT for survival. The outcome in those patients who had AT activity levels above 75% after FFP treatment was better than that of the nonresponding group. As well as AT, admission values of D-dimer, C-reactive protein, and procalcitonin were coagulation and inflammatory parameters among the mortality risk factors. Conclusion: AT activity could be used as a prognostic marker for survival and organ failure in COVID-19-associated ARDS patients. AT supplementation therapy with FFP in patients with COVID-19-induced hypercoagulopathy may improve thrombosis prophylaxis and thus have an impact on survival.

The Effect of Direct Oral Anticoagulants on Antithrombin Activity Testing Is Abolished by DOAC-Stop in Venous Thromboembolism Patients.

CONTEXT.­: Direct oral anticoagulants (DOACs) may cause false negative results of antithrombin (AT) deficiency screening. OBJECTIVE.­: To evaluate the impact of DOAC-Stop, an agent reversing in vitro effects of DOACs, on AT testing in anticoagulated patients. DESIGN.­: We assessed 130 venous thromboembolism patients aged 46.7 ± 13.5 years. Blood samples were collected 2 to 27 hours after DOAC intake from 49 patients on rivaroxaban, 54 on apixaban, and 27 on dabigatran. Antithrombin activity was assessed using the activated factor X (FXa)-based and the activated factor II (FIIa)-based method twice, before and after DOAC-Stop treatment, together with plasma DOAC levels using coagulometric assays. RESULTS.­: The use of DOAC-Stop did not influence AT activity measured using the FIIa-based assay, whereas there was a marked decrease in AT activity determined using the FXa-based assay (ΔAT = 16.9%; 95% CI, 12.9%-19.1%). The AT-FIIa assay revealed decreased AT level (<79%) in all 10 (7.7%) genetically confirmed AT-deficient patients treated with rivaroxaban or apixaban (n = 5 each), whereas the AT-FXa assay showed decreased AT activity (<83%) in 2 subjects on rivaroxaban and 1 on apixaban with low plasma DOAC concentrations (<90 ng/mL). After DOAC-Stop median AT-FXa activity lowered from 83.5% (interquartile range, 66%-143%) to 65.5% (interquartile range, 57%-75%; P = .005; ΔAT = 18%) in AT-deficient patients, without any false negative results. The ΔAT in the FXa-based assay correlated with rivaroxaban and apixaban concentrations in the AT-deficient patients (r = 0.99, P < .001). CONCLUSIONS.­: Application of DOAC-Stop enables reliable evaluation of AT deficiency screening in patients taking rivaroxaban or apixaban and tested using the FXa-based method.

Characteristics Behaviors of Coagulation and Fibrinolysis Markers in Acquired Thrombotic Thrombocytopenic Purpura.

INTRODUCTIONS: Patients with acquired thrombotic thrombocytopenic purpura (TTP) show no severe abnormalities in coagulation or fibrinolysis. However, the exact extent of the abnormalities is unclear. MATERIALS AND METHODS: This study analyzed 138 patients with acquired TTP and 46 patients with septic disseminated intravascular coagulation (DIC) who were included in a Japanese registry. Complete blood cell counts and 8 coagulation or fibrinolysis parameters were compared between the 2 groups. RESULTS: Platelet counts in the acquired TTP group were significantly lower than those in the septic DIC group (P < .001). The international normalized ratio of prothrombin time and the activated partial thromboplastin time in the septic DIC group were significantly higher and longer, respectively, than those in the acquired TTP group (P < .01). The antithrombin (AT) values were significantly lower in the septic DIC group than in the acquired TTP group (P < .001), the latter of which were almost normal. Although both groups revealed elevations of fibrinogen degradation product (FDP) and D-dimer, these levels were significantly higher in the septic DIC group than in the acquired TTP group (P < .001). Of 138 patients with acquired TTP, 25 (18.1%) were diagnosed with septic DIC by the diagnostic criteria of the Japanese Ministry Health, Labour and Welfare, and 78 (56.5%) by those of the Japanese Association of Acute Medicine. Receiver operating characteristic curve analysis showed that acquired TTP could be diagnosed based on severe thrombocytopenia (<20 × 109/L), normal AT level (>87%), and mildly elevated FDP (<23 µg/mL). CONCLUSIONS: Our results indicate that 3 routine laboratory tests could differentiate between acquired TTP and septic DIC.

Recurrent miscarriage is not associated with a higher prevalence of inherited and acquired thrombophilia.

PROBLEM: Although not being recommended in guidelines, many physicians perform routine screening for thrombophilia in RM patients suspecting a higher prevalence in these patients. The aim of this study was to analyze the prevalence of inherited and acquired thrombophilia in a large cohort of RM patients. METHOD OF STUDY: Within a multicenter case-control study, n = 820 RM patients and n = 141 controls were included. The prevalence of inherited and acquired thrombophilia including deficiency of protein C/S and antithrombin, elevation of factor VIII activity, APC resistance including mutation in the factor V Leiden gene, mutation in the prothrombin gene and antiphospholipid antibodies were assessed. Further, we performed a meta-analysis of the prevalence of thrombophilia in RM patients including studies between 01/2000 and 01/2020. RESULTS: An antiphospholipid syndrome (APLS) was only present in RM patients. Increased factor VIII concentration was significantly more prevalent in controls (RM vs controls: 5.8% vs 11.0%). None of the other thrombophilia did differ significantly between RM patients and controls. The meta-analysis revealed no significant difference in the occurrence of these thrombophilia between RM patients and controls. CONCLUSION: The prevalence of inherited thrombophilia does not differ between RM patients and controls. When analyzing rare events like thrombophilia, a high number of patients are needed to obtain reliable results, which might explain contradictory findings in previous studies analyzing small cohorts of RM patients. Despite being less prevalent than previously described, we still recommend screening for APLS as it is associated with severe pregnancy complications.

Thromboelastography clot strength profiles and effect of systemic anticoagulation in COVID-19 acute respiratory distress syndrome: a prospective, observational study.

OBJECTIVE: Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) infection may yield a hypercoagulable state with fibrinolysis impairment. We conducted a single-center observational study with the aim of analyzing the coagulation patterns of intensive care unit (ICU) COVID-19 patients with both standard laboratory and viscoelastic tests. The presence of coagulopathy at the onset of the infection and after seven days of systemic anticoagulant therapy was investigated. PATIENTS AND METHODS: Forty consecutive SARS-CoV-2 patients, admitted to the ICU of a University hospital in Italy between 29th February and 30th March 2020 were enrolled in the study, providing they fulfilled the acute respiratory distress syndrome criteria. They received full-dose anticoagulation, including Enoxaparin 0.5 mg·kg-1 subcutaneously twice a day, unfractionated Heparin 7500 units subcutaneously three times daily, or low-intensity Heparin infusion. Thromboelastographic (TEG) and laboratory parameters were measured at admission and after seven days. RESULTS: At baseline, patients showed elevated fibrinogen activity [rTEG-Ang 80.5° (78.7 to 81.5); TEG-ACT 78.5 sec (69.2 to 87.9)] and an increase in the maximum amplitude of clot strength [FF-MA 42.2 mm (30.9 to 49.2)]. No alterations in time of the enzymatic phase of coagulation [CKH-K and CKH-R, 1.1 min (0.85 to 1.3) and 6.6 min (5.2 to 7.5), respectively] were observed. Absent lysis of the clot at 30 minutes (LY30) was observed in all the studied population. Standard coagulation parameters were within the physiological range: [INR 1.09 (1.01 to 1.20), aPTT 34.5 sec (29.7 to 42.2), antithrombin 97.5% (89.5 to 115)]. However, plasma fibrinogen [512.5 mg·dl-1 (303.5 to 605)], and D-dimer levels [1752.5 ng·ml-1 (698.5 to 4434.5)], were persistently increased above the reference range. After seven days of full-dose anticoagulation, average TEG parameters were not different from baseline (rTEG-Ang p = 0.13, TEG-ACT p = 0.58, FF-MA p = 0.24, CK-R p = 0.19, CKH-R p  = 0.35), and a persistent increase in white blood cell count, platelet count and D-dimer was observed (white blood cell count p < 0.01, neutrophil count p = 0.02, lymphocyte count p < 0.01, platelet count p = 0.13 < 0.01, D-dimer levels p= 0.02). CONCLUSIONS: SARS-CoV-2 patients with acute respiratory distress syndrome show elevated fibrinogen activity, high D-dimer levels and maximum amplitude of clot strength. Platelet count, fibrinogen, and standard coagulation tests do not indicate a disseminated intravascular coagulation. At seven days, thromboelastographic abnormalities persist despite full-dose anticoagulation.

Coagulation profile of COVID-19 patients admitted to the ICU: An exploratory study.

BACKGROUND: Coagulation abnormalities in COVID-19 patients have not been addressed in depth. OBJECTIVE: To perform a longitudinal evaluation of coagulation profile of patients admitted to the ICU with COVID-19. METHODS: Conventional coagulation tests, rotational thromboelastometry (ROTEM), platelet function, fibrinolysis, antithrombin, protein C and S were measured at days 0, 1, 3, 7 and 14. Based on median total maximum SOFA score, patients were divided in two groups: SOFA ≤ 10 and SOFA > 10. RESULTS: Thirty patients were studied. Some conventional coagulation tests, as aPTT, PT and INR remained unchanged during the study period, while alterations on others coagulation laboratory tests were detected. Fibrinogen levels were increased in both groups. ROTEM maximum clot firmness increased in both groups from Day 0 to Day 14. Moreover, ROTEM-FIBTEM maximum clot firmness was high in both groups, with a slight decrease from day 0 to day 14 in group SOFA ≤ 10 and a slight increase during the same period in group SOFA > 10. Fibrinolysis was low and decreased over time in all groups, with the most pronounced decrease observed in INTEM maximum lysis in group SOFA > 10. Also, D-dimer plasma levels were higher than normal reference range in both groups and free protein S plasma levels were low in both groups at baseline and increased over time, Finally, patients in group SOFA > 10 had lower plasminogen levels and Protein C ​​than patients with SOFA <10, which may represent less fibrinolysis activity during a state of hypercoagulability. CONCLUSION: COVID-19 patients have a pronounced hypercoagulability state, characterized by impaired endogenous anticoagulation and decreased fibrinolysis. The magnitude of coagulation abnormalities seems to correlate with the severity of organ dysfunction. The hypercoagulability state of COVID-19 patients was not only detected by ROTEM but it much more complex, where changes were observed on the fibrinolytic and endogenous anticoagulation system.

Effect of Dabigatran on Clotting Time in the Clotpro Ecarin Clotting Assay: A Prospective, Single-Arm, Open-Label Study.

Routine coagulation tests do not enable rapid, accurate determination of direct oral anticoagulant (DOAC) therapy. The ecarin clotting assay (ECA), performed on the ClotPro viscoelastic testing device, may enable sensitive and specific detection of dabigatran. We assessed the association between trough plasma dabigatran concentration and clotting time (CT) in the ClotPro ECA, in patients with non-valvular atrial fibrillation (NVAF). Each patient provided a single venous blood sample, ∼1 hour before dabigatran dosing. The study included 118 patients, of whom 64 were receiving dabigatran 110 mg twice daily and 54 were receiving 150 mg twice daily. ECA CT was moderately correlated with trough plasma dabigatran concentration (r = 0.80, p < 0.001). Slight trends toward increased plasma dabigatran concentration and prolonged ECA CT were apparent with 150 mg versus the 110 mg dose (differences not statistically significant). Individuals with creatinine clearance below 50 mL/minute had significantly higher plasma dabigatran concentrations and significantly prolonged ECA CT versus those with creatinine clearance ≥50 mL/minute. In conclusion, this preliminary study has demonstrated that CT in the ClotPro ECA reflects the plasma concentration of dabigatran in patients with NVAF. The ECA could potentially be used to assess the impact of dabigatran on a patient's coagulation status.

Diet-Dependent and Diet-Independent Hemorheological Alterations in Celiac Disease: A Case-Control Study.

INTRODUCTION: Hemorheology is the study of the flow properties of the blood and its elements, which, together with natural anticoagulants, are important determinants of cardiovascular events. This study aimed to assess hemorheological and natural anticoagulant profiles of patients with celiac disease (CeD) comprehensively. METHODS: Our study is a case-control study (registered under ISRCTN49677481) comparing patients with CeD with age- and sex-matched control subjects (1:1). We measured erythrocyte deformability (ED) at high (3-30 Pa) and low shears (0.3-3 Pa), erythrocyte aggregation, whole blood viscosity, plasma viscosity, and natural anticoagulants (protein C, protein S, and antithrombin activity). Adherence to gluten-free diet was estimated through dietary interview and urine gluten immunogenic peptide (urine GIP) detection. RESULTS: After matching, we analyzed the data of 100 study participants. ED at high shears was impaired in CeD (P < 0.05 for all shears, confirmed by random forest analysis) independently of findings on CeD-specific serological assessment and urine GIP detection but slightly dependently on dietary adherence (P = 0.025 for 30 Pa shear). ED at low shears seemed to be impaired only in urine GIP+ CeD patients (P < 0.05 for all comparisons with urine GIP- CeD patients and control subjects). All parameters describing erythrocyte aggregation and whole blood viscosity were shifted toward a prothrombotic direction in patients with CeD with poor dietary adherence compared with those with good dietary adherence. Plasma viscosity and activity of natural anticoagulants did not differ across groups. DISCUSSION: We observed diet-dependent and diet-independent prothrombotic hemorheological alterations in CeD, which can contribute to the elevated cardiovascular risk. The untoward metabolic changes during gluten-free diet, which can further aggravate hemorheological status, may indicate the implementation of prevention strategies.(Equation is included in full-text article.).

Therapeutic Drug Monitoring of Direct Oral Anticoagulants May Increase Their Benefit-Risk Ratio.

The attractiveness of direct oral anticoagulants (DOACs) over vitamin K antagonists, in addition to a better benefit-risk ratio, stems from the fact that no therapeutic drug monitoring is deemed necessary. This has been recently mitigated by the fact that increased dabigatran (D) plasma levels have been associated with hemorrhages, and is currently under scrutiny of the European Medicines Agency. We aimed to evaluate, in real conditions of use, whether patients with out-of-range DOAC blood concentrations (too high or too low) were associated with bleeding or thrombosis. Patients treated with D or rivaroxaban (R) were prospectively included in a hospital cohort. D and R plasma levels were measured by high-pressure liquid chromatography-tandem mass spectrometry-at the physician's demand. We defined concentration range as "expected" within the 95% confidence interval of the mean concentration obtained from pivotal trials, and "out of range" when concentrations were outside of that interval. A blind assessment of concentrations versus occurrence of bleeding or thrombosis was performed by means of univariate and multivariate analysis. Three hundred and twenty-two patients (mean age 78.5 years ± 13.1), treated with D or R were included consecutively. They had a mean CHA2DS2-VASc at 4.4 ± 1.7 and a mean HAS-BLED score at 1.7 ± 0.9. Irrespective of the DOAC prescribed, patients presenting with out-of-range concentrations had significantly more bleeding or thrombosis than patients with expected concentrations (P < 0.001). Patients with bleeding were more prone to have concentrations beyond the 95 percentile (N = 62, P < 0.001), whereas patients with thrombosis were more likely to have concentrations below the fifth percentile (N = 26, P < 0.05). The main risks associated with hemorrhages were abnormal concentrations, a high HAS-BLED score, the patient's age, and the creatinine blood level. For thrombosis, a concentration below the fifth percentile was the only risk factor that was significant in our cohort. While D and R under current recommendation have a better benefit-risk ratio than warfarin, their safe usage could be further optimized by some degree of therapeutic monitoring.