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College of Pharmacy

HelixTalk Episode #80 - HIT Me With Your Best Shot: A Brief Review of Heparin-Induced Thrombocytopenia (HIT)

Date posted: June 26, 2018, 6:00 am

In this episode, we will review the diagnosis and treatment of heparin-induced thrombocytopenia (HIT).

Key Concepts

  1. The 4T score is used to stratify the suspicion of HIT in a patient with thrombocytopenia.  The 4T score can rule out HIT but cannot confirm the diagnosis.
  2. The HIT IgG antibody can rule out HIT but has a high false positive rate.  To confirm the diagnosis of HIT, a functional assay (SRA or HIPA) must be positive.
  3. Argatroban is the drug of choice for HIT.  Fondaparinux is becoming more commonly used but cannot be used in those with severe renal impairment.  Many other therapies recommended by the CHEST guidelines are no longer on the market in the United States.
  4. Patients with confirmed HIT will require full anticoagulation as an outpatient for 4 weeks (if no thrombi occurred) or 3 months (if a thrombus developed secondary to HIT).

References

  1. Linkins LA, Dans AL, Moores LK, et al. Treatment and prevention of heparin-induced thrombocytopenia: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012 Feb;141(2 Suppl):e495S-e530S. doi: 10.1378/chest.11-2303.
  2. Salter BS, Weiner MM, Trinh MA, et al. Heparin-Induced Thrombocytopenia: A Comprehensive Clinical Review. J Am Coll Cardiol. 2016 May 31;67(21):2519-32. doi: 10.1016/j.jacc.2016.02.073.