Antithrombotic treatment in COVID-19 – from theory to practical approach

Abstract

Although initially considered a strictly respiratory pathology, the novel coronavirus disease-19 (COVID-19) has emerged as a significant prothrombotic trigger, inducing hypercoagulable status and increased risk of thrombotic events. This is due to a plethora of mechanisms, either from inflammation-induced endothelial dysfunction, overexpression of procoagulant molecules doubled by down-regulation of physiological antithrombotic pathways, or from an exagerated response to otherwise normal procoagulant stimuli. This complex association of factors define the concept of immunothrombosis, which can be influenced by several antithrombotic medications. Despite the lack of an „universal” guideline, the general consensus is to recommend antithrombotic treatment in COVID-19 patients, but its administration should take into account the patient’s clinical status, comorbidities or the other previous indications for antithrombotic treatment. This precaution is due to the multiple drug interactions with antivirals or other molecules used in COVID-19. Concerning anticoagulant treatment, heparins are the optimal choice, compared to antivitamins K and direct oral anticoagulants (DOACs), because they exhibit the most protective effects doubled by the least interactions with other substances. Hospitalized patients should receive prophylactic doses of anticoagulation, but not for the prevention of arterial thrombosis, unless they have a previous indication such as atrial fibrillation or prosthetic valve. It is generally recommended that patients on chronic anticoagulant or antiplatelet therapy for other conditions will continue their prescribed medication, here including special categories such as pregnant women. However, non-hospitalized patients with mild forms of the disease should not be initiated anticoagulant and antiplatelet therapy unless they have other indication. Continuation of prophylaxis after discharge is a matter of debate, the existing data suggesting it may be considered in those patients at high risk for venous thromboembolism (VTE) and/or who had a moderate-severe form of the disease, always assessing the bleeding risk. Further data from extensive studies are required in order to standardize the antithrombotic approach in COVID-19 patients.