Patients with COVID-19 have a coagulopathy and high thrombotic risk. In a cohort of 69 intensive care unit (ICU) patients we investigated for evidence of heparin resistance in those that have received therapeutic anticoagulation. 15 of the patients have received therapeutic anticoagulation with either unfractionated heparin (UFH) or low molecular weight heparin (LMWH), of which full information was available on 14 patients. Heparin resistance to UFH was documented in 8/10 (80%) patients and sub-optimal peak anti-Xa following therapeutic LMWH in 5/5 (100%) patients where this was measured (some patients received both anticoagulants sequentially). Spiking plasma from 12 COVID-19 ICU patient samples demonstrated decreased in-vitro recovery of anti-Xa compared to normal pooled plasma. In conclusion, we have found evidence of heparin resistance in critically unwell COVID-19 patients. Further studies investigating this are required to determine the optimal thromboprophylaxis in COVID-19 and management of thrombotic episodes.
Keywords Thrombosis • Intensive care • COVID-19 • Heparin
Highlights• Heparin resistance with unfractionated heparin or suboptimal anti-Xa peak with low molecular weight heparin appeared common in COVID-19 intensive care unit patients that received therapeutic anticoagulation. • In-vitro spiking of COVID-19 samples from patients in intensive care unit with low molecular weight heparin failed to recover the anti-Xa level as would have been predicted. • COVID-19 patients have high factor VIII and fibrinogen with low antithrombin which could contribute to the picture seen. • Further studies are needed to confirm our findings and also describe the mechanism of heparin resistance in these patients as well as optimal management of thrombosis in COVID-19.
Introduction
Patients with COVID‐19 are known to have a coagulopathy with a thrombosis risk. It is unknown whether this is due to a generalized humoral prothrombotic state or endothelial factors such as inflammation and dysfunction. The aim was to further characterize thrombin generation using a novel analyser (ST Genesia, Diagnostica Stago, Asnières, France) and a panel of haematological analytes in patients with COVID‐19.
Methods
Platelet poor plasma of 34 patients with noncritical COVID‐19 was compared with 75 patients with critical COVID‐19 (as defined by WHO criteria) in a retrospective study by calibrated automated thrombography and ELISA. Patients were matched for baseline characteristics of age and gender.
Results
Critical patients had significantly increased fibrinogen, CRP, interleukin‐6 and D‐dimer compared to noncritical patients. Thrombin generation, in critical patients, was right shifted without significant differences in peak, velocity index or endogenous thrombin potential. Tissue plasminogen activator (tPA), tissue factor pathway inhibitor (TFPI) and vascular endothelial growth factor (VEGF) were significantly increased in the critical versus noncritical patients. Critically ill patients were on haemodiafiltration (31%; heparin used in the circuit) or often received escalated prophylactic low‐molecular weight heparin.
Conclusion
These results confirm increased fibrinogen and D‐dimer in critical COVID‐19‐infected patients. Importantly, disease severity did not increase thrombin generation (including thrombin‐antithrombin complexes and prothrombin fragment 1 + 2) when comparing both cohorts; counter‐intuitively critical patients were hypocoaguable. tPA, TFPI and VEGF were increased in critical patients, which are hypothesized to reflect endothelial dysfunction and/or contribution of heparin (which may cause endothelial TFPI/tPA release).
Dyspnea is a common symptom in ED patients contributing substantially to ED, hospital, and ICU workload. It is also associated with significant mortality. There are a wide variety of causes however chronic disease accounts for a large proportion.
To cite this article: van Hylckama Vlieg A, Baglin CA, Luddington R, MacDonald S, Rosendaal FR, Baglin TP. The risk of a first and a recurrent venous thrombosis associated with an elevated D-dimer level and an elevated thrombin potential: results of the THE-VTE study. J Thromb Haemost 2015; 13: 1642-52.
The thromboelastography trace provides a graphical and numerical representation of the viscoelastic changes associated with fibrin polymerization. When used with whole blood, the shape of this trace is a composite of the effects of white and red cell content and composition, platelet number and function, fibrinogen concentration, as well as coagulation protein function and balance. The trace is also influenced by pharmacological agents such as anticoagulants, antiplatelet therapy, and coagulation factor supplementation. As such the main role of this technology has been as a point-of-care device to guide transfusion of blood components. Recently the technology has moved from the cardiac and hepatic surgical settings, where most of the early work was focused, into other areas of hemostatic monitoring. New applications for pharmaceutical monitoring and patient screening are being explored. This review gives a broad overview of the applications of the technology. In particular it considers the factors that most influence the characteristics of the trace, be they preanalytical, analytical, or clinical.
Background Direct oral anticoagulants (DOACs) are prescribed for atrial fibrillation (AF) and venous thromboembolism (VTE) and both occur more frequently in obese patients. Outcomes from DOAC trials included few individuals ≥ 120 kg leading to uncertainty whether high body weight (BW) reduces DOAC concentrations.
Objectives This article investigates the relationship between factor Xa (FXa) inhibitor concentrations, BW, and renal function, and compares them in high BW patients with unselected populations.
Methods Consecutive patients in two United Kingdom centers, weighing ≥ 120 kg receiving 5 mg twice daily apixaban or 20 mg once daily rivaroxaban for AF or VTE were prospectively included. Peak or trough concentrations were measured using specific chromogenic assays, expressed in mean or median (5th–95th percentiles). On-therapy range was the interval from the 5th percentile trough concentration to the 95th percentile peak concentration.
Results One hundred patients were included; age range: 23 to 78 years, 31% were women, 58% had AF, creatinine clearance range: 67 to 474 mL/min. Median BW was 139 kg, and 84% had body mass index (BMI) ≥ 40 kg/m2. DOAC peak and trough concentrations varied from 44 to 727 and 14 to 299 ng/mL, respectively. There was no linear relationship between FXa inhibitor concentrations at peak or trough and BW or BMI, and creatinine clearance. Apixaban troughs in AF and rivaroxaban peaks in VTE were lower than in unselected populations. However, only two trough concentrations were below the expected range, and 109/116 were within the on-therapy range.
Conclusion These data indicated that obese or high BW patients generally achieve therapeutic FXa inhibitor concentrations. However, further investigations assessing clinical outcomes are required.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Introduction
There is an unmet need to characterize the diagnosis and management of patients with an unclassified bleeding disorder (UBD).
Methods
Retrospective review of registered patients with UBD at our centre. Assessment including rotational thromboelastometry (ROTEM) and thrombin generation (TG) were used.
Results
A total of 124 patients were identified; 91% female. Mean age of presentation was 38.3 years. Mean bleeding score was 8.8 (standard deviation [SD] 3.8); 6.6 in men (SD 1.4) and 9.7 in women (SD 3.3), which was significantly different (P < .05). In women, after deduction of scores for menorrhagia and postpartum haemorrhage, the mean score was 6.4 which was not significantly different to the male score (P = .11). Twenty‐three percent of patients have been transfused, 61% women had treatment for menorrhagia and 17% for epistaxis. TxA and desmopressin were effective at preventing bleeding in 69 procedures and 13 deliveries. TG revealed 26% patients with a long lag time and 19% with a decreased endogenous thrombin potential but no diagnostic pattern was seen. ROTEM (NATEM) was unable to characterize patients; 9% had a prolonged clot time or maximum lysis. ThromboGenomics was normal in 45 tested patients.
Conclusions
We provide data which shows the bleeding score is biased towards gynaecological bleeding but which remains elevated even when the bleeding score is deducted. Tranexamic acid and desmopressin are effective as haemostatic prophylaxis but there is an urgent need for clinical trials. In conclusion, we describe the use of the bleeding score in these patients and phenotype, diagnosis (including ThromboGenomic testing) and management with practice recommendations.
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