The objective of this trial is to demonstrate the clinical utility of fixed-dose SC Desirudin for the prophylaxis of thrombosis as an alternative to heparin-based anticoagulation.

Hospitalized patients who require DVT prophylaxis and who are not good candidates for heparin-based anti-coagulation were eligible.

Inclusion Criteria:

1. Provide written informed consent before initiation of any study related procedures.
2. Be at least 18 years of age.
3. Patients requiring anticoagulation for the prophylaxis of thrombosis.
4. In the opinion of the Investigator, an alternative to heparin-based anticoagulant therapies is desirable.

Exclusion Criteria:

1. Confirmed pregnancy (if woman of child-bearing potential) (urine or serum pregnancy test).
2. Intracranial neoplasm, arteriovenous malformation or aneurysm.
3. Severe renal insufficiency (chronic or acute) with a GFR of < or equal to 30 mL/min as determined by measured or estimated creatinine clearance using Cockroft-Gault method or by estimated GFR using the MDRD formula.
4. Known allergy to desirudin or hirudin-derived drugs, or known sensitivity to any component of the product
5. Participation in other clinical research studies involving the evaluation of other investigational or FDA-approved drugs or devices within 30 days of enrollment (participation in observational studies of FDA-approved products is acceptable).
6. Refusal to undergo blood transfusion should it become necessary
7. Active bleeding or irreversible coagulation abnormality.
8. Uncontrolled hypertension defined as a blood pressure > or equal to 180/110 mmHg.
9. Patients requiring anticoagulation for left-ventricular assist device, intra-aortic balloon pump, veno-venous ultra filtration or ECMO.
10. Any other disease or condition which, in the judgment of the Investigator, would place a patient at undue risk by being enrolled in the trial, or cause inability to comply with the trial.