Inclusion Criteria:  Adult (age 18 or older) Documented SCD New or pre-existing CVC planned for long term use (at least 6 months) Able to provide written consent  Exclusion Criteria:  Contra-indication to prophylactic dose anticoagulation or active bleeding at discretion of treating physician Already on anticoagulation (prophylactic or therapeutic dose) for an indication other than CVC thromboprophylaxis Previous VTE within the past 3 months Pregnant, within 6 weeks post-partum, or active breast feeding Creatinine clearance <30mL/min (as calculated by Cockcroft-Gault equation[67]) Acute hepatitis or chronic active hepatitis Cirrhosis with Child-Pugh score B or C Platelet count < 50 x109/L Weight <40kg Uncontrolled HTN (systolic blood pressure > 170mmhg, or diastolic blood pressure> 100mmhg) despite antihypertensive treatment On palliative care On dual antiplatelet therapy, or high dose single agent aspirin > 325mg/day On combined P-glycoprotein and strong cytochrome P450 3A4 inhibitors (including but not limited to ketoconazole and protease inhibitors) On combined P-glycoprotein and strong cytochrome P450 3A4 inducers (including but not limited to rifampin, phenytoin, phenobarbital, carbamazepine, and st. john's wort) Active cancer or treatment for cancer excluding basal cell carcinoma Known allergy to study drug Strong indication for thromboprophylaxis at discretion of treating physician Significant medical condition that confers an unacceptable risk to participating in the study, and/or that could confound the interpretation of the study data.