Multi-Center Single Arm Trial to Determine The Effectiveness of Warfarin Therapy Duration For Heparin-Induced Thrombocytopenia (HIT)

Inclusion criteria: * Patient must be able to provide an informed consent * Patient older than 18 years' old * Patient with suspected diagnosis of HIT, need 2 of the following: have a fall in platelet count of \> 30% from a baseline prior to heparin/LMWH Platelet factor 4 (PF4) ELISA positive Develop skin lesions secondary to subcutaneous heparin With T score more than 4 For those less than 4 we will use serotonin release assay-SRA * Patient received the bridging therapy of non-heparin anticoagulant * Patient is receiving the standard of care treatment for HIT * Patient is willing to be followed up for by one of the physicians listed in the delegation log * The Primary physician responsible for the patient is agreeing for the patient to participate * Patients are not involved in a clinical trial for HIT management Exclusion Criteria: * Patient is unable to sign an informed consent * Patient doesn't have a confirmed diagnosis of HIT * Patient Does not have Pulmonary embolus * Patient does is not on Warfarin for other indications * Patient is a known case of hypercoagulable disorder * Patient is not willing to come back for follow up * Patient is critically ill or has a life expectancy of less than 3 months * Pregnancy that is in First trimester. * Multi-system organ failure or estimated survival of less than 30 days * Uncontrolled hypertension defined as a blood pressure \>180/110 mm Hg