Post-thrombotic Syndrome & Predictors of Recurrence in Catheter-related Thrombosis

Inclusion Criteria: * Upper extremity venous thrombosis associated with an indwelling catheter documented by ultrasound, CT or venography * Current hematologic or solid tumor malignancy undergoing chemotherapy, surgery, radiation or hormonal therapy for malignancy. * \>18 years of age * Platelet count \>50,000 * Creatinine clearance \>30 ml/min * Ability to provide informed consent Exclusion Criteria: * Underlying medical condition or chemotherapy requiring long-term anticoagulation * Known underlying higher risk thrombophilias including antiphospholipid antibody syndrome, antithrombin, protein C or protein S deficiencies, or homozygosity or compound heterozygosity for prothrombin G20210A or Factor V R506Q mutations. * Inability to remove venous catheter * Anticipated replacement of central venous catheter within 3 months * Major bleeding or clinically relevant non-major bleeding in the preceding 60 days * Participation in another clinical trial that requires anticoagulation * Use of anticoagulant other than low-molecular weight heparin * Treatment with thrombolysis * Catheter removal \>1 month prior to enrollment