ABRIDGE: Low Molecular Weight Heparin in Bridging Patients After Mechanical Valve Replacement

Patients meeting all the following will be considered for enrollment.

1. Male or non-pregnant female (negative pregnancy test is required for women of child bearing potential) ≥ 18 of age who are able to provide informed consent and able to self-administer enoxaparin.
2. Body weight ≥ 45kg and ≤ 150kg.

3. Patients who are post prosthetic mechanical valve surgery and will need oral anticoagulation after discharge from the hospital.

   • One who has undergone valve replacement with mechanical prosthesis in the mitral position.
   • One who has undergone valve replacement with mechanical prosthesis in the aortic position.
   • One who has undergone valve replacement with mechanical prosthesis in the tricuspid position.

Exclusion Criteria:

Patients with any of the following will not be eligible for enrollment in the study:

1. Contraindication or sensitivity to unfractionated heparin/ low molecular weight heparin: history of heparin associated thrombocytopenia, heparin induced thrombocytopenia, or heparin induced thrombotic thrombocytopenia syndrome;
2. History of, or current, cardiogenic shock;
3. Active endocarditis (requiring > 4 weeks of antibiotics);
4. Active bleeding or bleeding diathesis;
5. History of gastrointestinal bleeding and /or endoscopically verified ulcer disease within the last three months;
6. Known proliferative diabetic retinopathy or history of intraocular bleeding;
7. Ischemic stroke in the previous three months or any hemorrhagic stroke, known brain tumor, intracranial aneurysm or intracranial AV malformation;

8. Renal insufficiency (cr clearance \< 30 cc/min), cr clearance calculation:

   Women = 0.85 x (140 - age) x body weight (kg) / 72 x serum creat (mg/dl), Men = (140 - age) x body weight (kg) / 72 x serum creat (mg/dl), or patient with a renal transplant;

9. Anemia (Hgb \< 8 gm/dl);
10. Thrombocytopenia (platelet count \< 100 x 109/L);
11. Liver disease demonstrated by ALT > 144u/L
12. Uncontrolled hypertension (systolic blood pressure >180mmHg or diastolic blood pressure >100mmHg);
13. Life expectancy less than 6 months;
14. Moderate pericardial effusion as diagnosed by echo;
15. Concomitant use of clopidogrel, or cyclooxygenase 1 or 2 inhibitors or use within seven days;

Non- medical exclusion

1. Patients unable or unwilling to provide consent.
2. Patients unable or unwilling to have follow-up echocardiogram.