Pulmonary embolism in patients with COVID-19 pneumonia on adequate oral anticoagulation.

Thrombotic complications are common in patients with severe COVID-19 pneumonia with important consequences on the diagnostic and therapeutic management. We report a consecutive series of five patients on long-term oral anticoagulation therapy who presented to our hospital for severe COVID-19 pneumonia associated with segmental acute pulmonary embolism despite adherence to therapy and with an adequate anticoagulant range at the time of the event. Four patients were receiving a direct oral anticoagulant (two with edoxaban, one with rivaroxaban and one with apixaban) and one patient a vitamin K antagonist. No significant thrombotic risk factors, active cancer, or detectable venous thromboembolism were present. In all cases, elevated d-dimer and fibrinogen levels with a parallel rise in markers of inflammation were documented. The combination of these findings seems to support the hypothesis that considers the local vascular damage determined by severe viral infection as the main trigger of thrombi detected in the lungs, rather than emboli from peripheral veins.