COVID-19 is an
infection induced by the SARS-CoV-2 coronavirus, and severe forms can lead to
acute respiratory distress syndrome (ARDS) requiring intensive care unit (ICU) management. Severe forms are associated with coagulation changes, mainly characterized by an increase in
D-dimer and
fibrinogen levels, with a higher risk of
thrombosis, particularly
pulmonary embolism. The impact of
obesity in severe
COVID-19 has also been highlighted.In this context, standard doses of
low molecular weight heparin (
LMWH) may be inadequate in ICU patients, with
obesity, major
inflammation, and
hypercoagulability. We therefore urgently developed proposals on the prevention of
thromboembolism and monitoring of hemostasis in hospitalized patients with COVID-19.Four levels of thromboembolic risk were defined according to the severity of
COVID-19 reflected by
oxygen requirement and treatment, the body mass index, and other risk factors. Monitoring of hemostasis (including
fibrinogen and
D-dimer levels) every 48 h is proposed. Standard doses of
LMWH (e.g.,
enoxaparin 4000 IU/24 h SC) are proposed in case of intermediate thrombotic risk (BMI < 30 kg/m2, no other risk factors and no ARDS). In all obese patients (high thrombotic risk), adjusted prophylaxis with intermediate doses of
LMWH (e.g.,
enoxaparin 4000 IU/12 h SC or 6000 IU/12 h SC if weight > 120 kg), or
unfractionated heparin (UFH) if
renal insufficiency (200 IU/kg/24 h, IV), is proposed. The thrombotic risk was defined as very high in obese patients with ARDS and added risk factors for
thromboembolism, and also in case of
extracorporeal membrane oxygenation (ECMO), unexplained
catheter thrombosis, dialysis filter
thrombosis, or marked inflammatory syndrome and/or
hypercoagulability (e.g.,
fibrinogen > 8 g/l and/or D-dimers > 3 μg/ml). In ICU patients, it is sometimes difficult to confirm a diagnosis of
thrombosis, and curative
anticoagulant treatment may also be discussed on a probabilistic basis. In all these situations, therapeutic doses of
LMWH, or UFH in case of
renal insufficiency with monitoring of anti-Xa activity, are proposed.In conclusion, intensification of
heparin treatment should be considered in the context of
COVID-19 on the basis of clinical and biological criteria of severity, especially in severely ill ventilated patients, for whom the diagnosis of
pulmonary embolism cannot be easily confirmed.