A blood clot in the veins, also known as deep venous thrombosis (DVT), is one of the most common complications after surgery. This may result in death if a clot breaks off and travel to the lungs; this is referred to as pulmonary embolism (PE). After heart surgery the incidence of DVT ranges from 20-48% and following lung surgery the incidence is 19-26%. In order to decrease the likelihood of this complication, patients receive by injection a blood thinning medicine. Heparin is the usual medicine used for this purpose following heart and lung surgery. Recently there have been reports that other medicines may be more effective than heparin for this purpose. Also there have been reports that some patients develop antibodies to heparin. When this occurs, this may prevent the heparin from being effective and may even promote the formation of blood clots. Antibodies to heparin may be present more often following heart and lung surgery than other types of surgery. There is a new medicine called desirudin (Iprivask), which may be used instead of heparin to prevent blood clots following heart and lung surgery. Desirudin is currently approved by the FDA to prevent blood clots following hip surgery. The purpose of this study is to compare desirudin with heparin for the prevention of vein clots after heart and lung surgery.

Inclusion Criteria:

• Patients who are scheduled for elective Cardiac or Thoracic Surgery.
• Age > 18 years of age.

Exclusion Criteria:

• Patients with a clinical suspicion or a documented history of DVT/PE
• Patients who may require anticoagulation during the post-op period. (i.e. Patients with a history of A-fib, scheduled for a MAZE procedure or placement of a mechanical valve, or those on Coumadin/IV heparin preoperatively)
• Patients who have a history of HIT or if there is a suspicion of the patient having HIT pre-operatively.
• Documented allergy to heparin, desirudin, or lepirudin
• Patients with a history of coagulation disorder
• Platelet count< 100 X109 /dl
• Active bleeding
• Serum Creatinine ≥ 1.5 mg/dl or CrCl ≤ 30 ml/min
• Patients with a baseline coagulopathy (INR > 1.5 or aPTT > 45 sec)
• Patients with liver disease
• Pregnancy
• Patients who require ventricular assist devices before or after surgery

The study size was small and a surrogate end point was the primary outcome. The study was not powered to show statistical differences in clinical outcomes. Many patients received both desirudin and heparin during the study.