Successful treatment of a massive pulmonary embolism using rivaroxaban in a patient with antithrombin III deficiency.

We report a case of acute massive pulmonary embolism in a patient with antithrombin III deficiency. The patient was treated with rivaroxaban. The patient responded well to the therapy, and contrast-enhanced computed tomography showed nearly complete disappearance of the pulmonary embolism. Patients with low antithrombin III activity may have resistance to heparin therapy, leading to insufficient anticoagulation during the acute phase of thromboembolism. This case suggests that direct oral anticoagulants, such as rivaroxaban, may be effective first-line agents for treating venous thromboembolism in patients with antithrombin III deficiency. <Learning objective: Recently, direct oral anticoagulants represent a novel treatment option for venous thromboembolism with several practical advantages over conventional therapy. Antithrombin-III deficiency may lead to insufficient anticoagulation during the acute phase of thromboembolism. The present case suggests that rivaroxaban is a direct Factor Xa inhibitor and does not require cofactors such as antithrombin-III, thus it is suitable for anticoagulation therapy in patients with low antithrombin-III activity.>.