This will be a prospective cohort study of patients who present with an acute upper limb thrombosis in the setting of a central venous catheter. The total study duration will be 12 weeks, with one follow up telephone visit at 6 months. All patients will be treated with rivaroxaban at a dose of 15 mg orally twice daily for three weeks, followed by 20 mg daily. Anticoagulation will continue for three months regardless of the length of time the catheter is in place. Continuation of anticoagulation beyond this time period is at the discretion of the investigators.