Overview of Current Evidence on the Impact of the Initial High Dose of the Direct Factor Xa Inhibitor Rivaroxaban on Thrombus Resolution in the Treatment of Venous Thromboembolism

Incomplete thrombus resolution in patients with venous thromboembolism (VTE) may increase the risk of recurrent thromboembolic events and other complications, such as post-thrombotic syndrome. Various options exist for thrombus resolution, including systemic thrombolytic agents, catheter-directed thrombolysis, and traditional anticoagulants such as heparins or vitamin K antagonists (VKAs). Data are accumulating on the use of non-VKA oral anticoagulants, such as rivaroxaban, and these may provide greater thrombus resolution compared with VKAs. Data from the phase III rivaroxaban studies presented here show that a 21-day intensive dosing regimen of rivaroxaban 15 mg twice daily is effective during the acute treatment phase for VTE, with similar recurrence rates and thrombus resolution to standard anticoagulation. Pooled analyses of phase III studies have also indicated that rivaroxaban 20 mg once daily monotherapy for up to 12 months after this initial intensive treatment period may provide effective prevention of recurrent VTE and a reduction in the risk of major bleeding, irrespective of clot burden. Four case studies from the Darmstadt Academic Teaching Hospital, Germany, and Gunma University Hospital, Japan, are also provided. Further clinical studies and real-world data may improve our understanding of initial intensive dose regimens, and assess the full significance of thrombus burden in VTE.