THromboprophylaxis In Sickle Cell Disease With Central Venous Catheters (THIS)

Inclusion Criteria: 1. Adult (age 18 or older) 2. Documented SCD 3. New or pre-existing CVC planned for long term use (at least 6 months) 4. Able to provide written consent Exclusion Criteria: 1. Contra-indication to prophylactic dose anticoagulation or active bleeding at discretion of treating physician 2. Already on anticoagulation (prophylactic or therapeutic dose) for an indication other than CVC thromboprophylaxis 3. Previous VTE within the past 3 months 4. Pregnant, within 6 weeks post-partum, or active breast feeding 5. Creatinine clearance \<30mL/min (as calculated by Cockcroft-Gault equation\[67\]) 6. Acute hepatitis or chronic active hepatitis 7. Cirrhosis with Child-Pugh score B or C 8. Platelet count \< 50 x109/L 9. Weight \<40kg 10. Uncontrolled HTN (systolic blood pressure \> 170mmhg, or diastolic blood pressure\> 100mmhg) despite antihypertensive treatment 11. On palliative care 12. On dual antiplatelet therapy, or high dose single agent aspirin \> 325mg/day 13. On combined P-glycoprotein and strong cytochrome P450 3A4 inhibitors (including but not limited to ketoconazole and protease inhibitors) 14. On combined P-glycoprotein and strong cytochrome P450 3A4 inducers (including but not limited to rifampin, phenytoin, phenobarbital, carbamazepine, and st. john's wort) 15. Active cancer or treatment for cancer excluding basal cell carcinoma 16. Known allergy to study drug 17. Strong indication for thromboprophylaxis at discretion of treating physician 18. Significant medical condition that confers an unacceptable risk to participating in the study, and/or that could confound the interpretation of the study data.