Anticoagulation in coronavirus disease 2019 (COVID-19): confirmed and controversial aspects

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with a high risk of microvascular immunothrombosis as well as symptomatic and incidental thromboembolisms, predominantly in the venous system but also in the arterial system. This explains among other things the high cardiovascular morbidity and mortality of the patients. The present state of knowledge on the pathophysiology of immunothrombosis and the strategies of anticoagulation in patients with coronavirus disease 2019 (COVID-19) are summarized and illuminated in this article. According to the current guidelines moderately to severely ill patients who are being treated in hospital should receive thrombosis prophylaxis with low molecular weight or unfractionated heparin or alternatively with fondaparinux, as long as there is no clearly increased risk of bleeding. Apart from the established indications for treatment, an intensified or therapeutic dose prophylaxis should be considered very cautiously in these critically ill patients, also due to the increased bleeding complications. The routine continuation of prophylactic anticoagulation after discharge from hospital is currently not recommended.