Abstract Number: PB0230
Meeting: ISTH 2021 Congress
Background: During the first wave of COVID-19 infections, a significantly higher incidence of thrombo-embolic events (TE) was reported. This led to some international guidelines favouring the administration of a higher dose of low molecular weight heparin (LMWH) as a prophylactic anticoagulation strategy. Despite switching to a dose of 100 IU/kg tinzaparin in COVID-19 infected patients in our intensive care unit (ICU), we still experienced several ischemic events.
Aims: To establish if anti-Xa plasma levels can determine the development of TE in COVID-19 infected ICU patients.
Methods: After obtaining ethical approval, we retrospectively collected data on anti-Xa levels from all COVID-19 infected ICU patients, treated once daily with tinzaparin, on 2 random dates in November 2020 in UZ Brussel. Samples were obtained 4 hours after injection, as required to measure reliable peak levels. We investigated whether these patients developed a TE within 14 days following sample collection.
Results: We analysed 32 anti-Xa plasma levels from 24 patients, 19 from patients receiving a high prophylactic dose of tinzaparin (median dose=103 IU/kg) and 13 from patients receiving a therapeutic dose (median dose=177 IU/kg). None of the patients in the therapeutic group developed a TE within 14 days, in contrast with 6 patients in the high prophylactic group (Figure 1). All patients with anti-Xa levels below 0.23 IU/mL (n=4) developed a TE, as opposed to only 2 out of 15 with higher levels. However, due to a wide range in anti-Xa levels and a small sample size, there was no statistically significant difference in anti-Xa levels in patients with and without TE (p-value=0.123).
Conclusions: Anti-Xa peak levels below 0.23 IU/mL might predict TE within 14 days in COVID-19 infected ICU patients receiving a high prophylactic dose of LMWH. After validation in larger patient groups, this could lead to integration of systematic anti-Xa level monitoring in future COVID-19 guidelines.
To cite this abstract in AMA style:Van Lancker R, Demeester S, Jochmans K, Mekeirele M. Anticoagulation with Tinzaparin in COVID-19 Patients in ICU: Are Low Anti-Xa Levels Associated with the Development of Thrombo-embolic Events? [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/anticoagulation-with-tinzaparin-in-covid-19-patients-in-icu-are-low-anti-xa-levels-associated-with-the-development-of-thrombo-embolic-events/. Accessed November 29, 2023.
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