Venous thromboembolism in the era of COVID-19

Coronavirus disease 2019 (COVID-19) does not only affect the respiratory system but appears to be a systemic disease. Venous thromboembolism is a common manifestation in hospitalized patients with COVID-19 with a reported incidence that is significantly higher compared to other acute viral infections. The pathophysiology mechanisms have not been fully explored and autopsy studies might enhance our understanding on this topic. Microthrombi formation occurs mainly in the pulmonary vasculature but can also occur in other organs. The high inflammatory burden related to COVID-19 seems to be associated with the coexisting coagulopathy. Concomitant manifestations of COVID-19, such as severe pneumonia, which has similar clinical presentation with pulmonary embolism (PE), and barriers related to strict isolation protocols are the two main reasons why PE diagnosis might be more challenging in patients with COVID-19. Medical societies have published guidance reports suggesting the administration of prophylactic anticoagulant therapy in hospitalized patients with COVID-19, but several questions regarding the optimal acute and long-term treatment of these patients remain unanswered.