Anticoagulation Options for Coronavirus Disease 2019 (COVID-19)-Induced Coagulopathy

As the coronavirus disease 2019 (COVID-19) pandemic is evolving, coagulopathy induced by the disease and its severe complications are raising concerns in the medical community. Because coagulopathy caused by COVID-19 has been difficult to control, it is important to have a better understanding of what therapies have been studied thus far and what therapies have demonstrated better outcomes for hospitalized patients. This review is focused on literature, research, and expert clinical judgments published in 2020 with a few references to articles published earlier. The review introduces the interim guidelines of the International Society of Thrombosis and Haemostasis (ISTH) for management of COVID-19-induced coagulopathy, discusses the efficacy of these guidelines in clinical settings, and summarizes the response of the scientific community to these guidelines and their clinical implications. Due to the failure of patients to respond to the prophylactic doses of heparin recommended by ISTH, higher doses of heparin may be necessary to achieve adequate anticoagulation. Patients' resistance to prophylactic doses of heparin could be due to low levels of anti-thrombin and high levels of fibrinogen, which would reinforce the use of therapeutic doses of heparin in the early stages of hospitalization. The review also compares low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) as anticoagulant choices for COVID-19 patients. Given the complications specific to COVID-19, UFH may be a better choice of anticoagulant. Outpatient anticoagulation options are also reviewed. Changing qualified patients from vitamin K antagonists (VKA) to direct-acting oral anticoagulant (DOAC) for the convenience of less frequent monitoring may be appropriate. New anticoagulant, nafamostat, used in Japan is also discussed as a possible potentiate for heparin therapy.