Comparison of Bleeding Risk Between Rivaroxaban and Apixaban: The Pilot Study

This vanguard pilot study compares rivaroxaban and apixaban, two of the new oral blood thinners for the treatment of blood clots. Half of the patients will receive apixaban and half will receive rivaroxaban. The main objective is to determine the feasibility of patient recruitment and resources required to follow enrolled patients and inform for a larger, multi-centered trial and to assess which one is safer.

Inclusion Criteria: * Confirmed newly diagnosed acute VTE (proximal lower extremity deep vein thrombosis and segmental or greater pulmonary embolism) * Age ≥ 18 years old * Written informed consent Exclusion Criteria: * Any contraindication for anticoagulation such as active bleeding * Clinically significant liver disease or alanine aminotransferase (ALT) levels ≥ 3 times the upper limit of normal range * Creatinine clearance \< 30 ml/min calculated with the Cockcroft-Gault formula (29) * Known allergies to either apixaban or rivaroxaban * Pregnancy * Use of contraindicated medications with apixaban or rivaroxaban * Active malignancy in the last 6 months (excluding localized skin malignancy) * No private insurance coverage for the study drug or not willing to pay for study drug