Significance of Antibodies to Heparin/Platelet Factor 4 Complex in Vein Graft Patency and Potential Role of Argatroban for Prevention of Vein Graft Occlusion

Inclusion Criteria: 1. Patients scheduled for CABG (males or non-pregnant females) 2. \> 18 years old with at least one vein graft planned 3. Able to provide written informed consent Exclusion Criteria: 1. Patients who, in the investigator's or attending surgeon's opinion, are unsuitable for anticoagulation due to their clinical status 2. Documented history of allergy to iodinated contrast media, warfarin, or argatroban 3. Chronic renal impairment with CrCl\<60 ml/min 4. Recent bleeding episode 5. Congestive Heart Failure (EF\< 30%) 6. Bleeding diathesis or known thrombophilic disorder 7. Atrial fibrillation or other condition requiring anticoagulation at the time of enrollment 8. Documented history of heparin induced thrombocytopenia 9. Clinical suspicion of HIT at the time of randomization, defined as 50% decrease in Platelet count from last heparin exposure or Platelet count \<100,000/ml 10. Hepatic dysfunction (defined as LFTs \> 3 times the upper limit of normal) 11. Patients with a history of bleeding complications post-CABG 12. Hemorrhagic stroke 13. Gastrointestinal bleeding 14. Requirement for fresh frozen plasma 15. Recent central nervous system or ophthalmic surgery 16. Aneurysm 17. History of psychosis or senility 18. Malignant hypertension 19. Clinically significant pericarditis or pericardial effusion 20. Bacterial endocarditis 21. Hematocrit \< 24% 22. Valve replacement or repair at time of CABG 23. Subjects with signs or symptoms of possible Transient Ischemic Attack or stroke