Breakthrough venous thromboembolic events in five patients with COVID‐19 on direct oral anticoagulants

What is known and objective Coronavirus disease 2019 (COVID‐19) is associated with increased risk of venous thromboembolism (VTE). Guidance for VTE prophylaxis continues to evolve, including addressing direct oral anticoagulants (DOACs) continued upon hospitalization. Case summaries We present 5 patients hospitalized for COVID‐19 while on DOACs. Four patients had atrial fibrillation and had a previous VTE. Four patients developed acute VTE and one developed stroke‐like symptoms. Monitoring D‐dimer assisted with the detection of VTE. Three patients died, and two were discharged alive. What is new and conclusion Therapeutic failure with DOACs appears to be commonplace in COVID‐19. Further research is needed to determine whether there is an underlying cause to this association. Heparin‐based therapies possess anticoagulant and anti‐inflammatory properties which may be preferred over direct oral anticoagulants (DOACS) in COVID‐19. D‐dimers are often used to supplement the evaluation of venous thromboembolism (VTE) prophylaxis. This case series describes a high incidence of breakthrough VTE in patients on DOACs.