**1. Introduction**

SARS-CoV-2 causing coronavirus disease (COVID-19) is a proinflammatory and prothrombogenic virus with a high mutation rate, producing active infection of variable duration in various organs and systems [1, 2]. The disease is highly heterogeneous in its manifestations and, although in most cases resolve asymptomatically or mildly, it can lead to severe symptoms and even death [3, 4]. In hospitalised patients with COVID-19, due to the procoagulant state and the increased risk of thromboembolic events, the use of anticoagulation for prophylactic purposes is recommended [5], and heparin is of great benefit in the treatment and prevention of venous and arterial micro- and macro-thrombosis [6]. Given reports of excess thrombotic risk, dose-escalating anticoagulation strategies have been incorporated into some COVID-19 clinical guidelines [7]. However, the effectiveness and safety of therapeutic/intermediate/prophylactic anticoagulation doses in COVID-19 are uncertain and remain under study [8].
