key: cord-0963326-9m2wtmuc
authors: Vlot, E.A.; Van den Dool, E.J.; Hackeng, C.M.; Sohne, M.; Noordzij, P.G.; Van Dongen, E.P.A.
title: Anti Xa activity after high dose LMWH thrombosis prophylaxis in covid 19 patients at the intensive care unit
date: 2020-07-22
journal: Thromb Res
DOI: 10.1016/j.thromres.2020.07.035
sha: 32ea21aa0d3b8e71c433b6917bf6d1616a5c2886
doc_id: 963326
cord_uid: 9m2wtmuc

INTRODUCTION: Coagulopathy in Coronavirus disease 2019 (covid-19) has been demonstrated by an increase in D-dimer, prothrombin time (PT), fibrinogen and factor VIII. Venous thromboembolic events are a common abnormality in patients with covid-19. We evaluate the results of intensive care unit (ICU) thrombosis prophylaxis of 5700 international unit (IU) nadroparin low molecular weight heparin (LMWH) twice daily. METHODS: After introduction of this high-dose pharmacological thrombosis prophylaxis twice weekly anti-factor Xa (anti Xa) concentrations and results from routine laboratory and viscoelastic hemostatic tests in 16 ICU covid-19 patients were evaluated. RESULTS: During one week, median peak anti Xa activities were 0.38 [0.16–0.45] and 0.38 [0.20–0.58] at time point 1 and 2 respectively. Laboratory coagulation tests showed PT, AT and platelet count (PltC) values within normal range and markedly increased D-dimer and fibrinogen levels. Viscoelastic tests showed a maximum clot strength just above normal reference value, while fibrin clot strength was strongly increased. The overall contribution of fibrin to clot strength was high with 71 [56–85]%. CONCLUSION: Anti Xa activity was within the target range of pharmacodynamic endpoint for covid-19 patients but viscoelastic tests still demonstrated a procoagulant pattern.

J o u r n a l P r e -p r o o f of viscoelastic hemostatic assays has been the focus of research in management of coagulopathy after cardiovascular surgery, other major surgery and trauma [7] . To investigate if viscoelastic testing might have a role in understanding the coagulopathy in the group of covid-19 patients, thromboelastography (TEG) assay was performed.

Here we report anti Xa levels in ICU patients diagnosed with covid-19 upon this high-dose pharmacological thrombosis prophylaxis. In addition, results from routine laboratory and viscoelastic hemostatic tests are reported.

Data were obtained over a follow-up period of one week and comprised in total 16 ICU patients on mechanical ventilation. Five patients were admitted directly from the emergency department, two patients were transferred from other ICUs in the country, and the remaining 9 patients were admitted from the covid hospital wards. Data regarding medical history, medication use before hospital admission and laboratory data were collected from electronic patient files. Local Medical Research Ethics Committee approval was obtained with a waiver for patient informed consent due to the observational nature of the study.

For coagulation testing whole blood was sampled in 3.2% sodium citrate tubes (BD Vacutainer), performed at the hospital clinical chemistry laboratory. Daily performed coagulation analyses included PT, activated partial thromboplastine time (aPTT), D-dimer, fibrinogen, antithrombin activity (AT) and PltC. Blood sampling for anti Xa activity was performed twice a week with a measurement taken around 4 hours after dosing (peak anti-Xa). 

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