The Primary Prevention of Venous Thromboembolism in Patients with COVID-19 in Japan: Current Status and Future Perspective.

Coronavirus disease 2019 (COVID-19) has become a huge threat worldwide as a pandemic, which could also cause venous thromboembolism (VTE), including pulmonary embolism (PE). On the basis of the concept of the high risk for VTE in patients with COVID-19, some studies reported the potential benefit of anticoagulation for the primary prevention of VTE. However, optimal strategies for the prevention of VTE in COVID-19 still remain unknown. Additionally, ethnic differences may have notable implications in the presentation of VTE. Very recently, in the Japanese Society of Phlebology and Japanese Society of Pulmonary Embolism Research, a questionnaire surveillance for COVID-19 and VTE was conducted, which revealed that the vast majority of the institutions did not have specific recommendations for the prevention of VTE with anticoagulation, the incidence rate of VTE was 0.6% (7/1243), and that of PE was 0.4% (5/1243). The current questionnaire surveillance has suggested that the management strategies for the prevention of VTE by anticoagulation in COVID-19 could widely vary according to institutions, and the number of patients diagnosed as VTE in COVID-19 in Japan was quite small compared with reports from other countries. Further studies, including cohort/registry-based studies, are warranted to confirm these results.