Heparin Induced Thrombocytopenia (HIT)

Author

Tanya YatskivFollow

Date of Award

Winter 12-15-2023

Document Type

Dissertation

Degree Name

Doctor of Medical Science (DMSc)

Department

Department of Physician Assistant Medicine

First Advisor

Lauren Myers, PA-C

Second Advisor

Nicholas Barber, MD

Third Advisor

Kristy Asbell, PA-C

Abstract

Introduction:

Heparin was first discovered in 1915 and is still widely used to this day.1 In 1958 however, it was noted that a small percentage of recipients of heparin develop antibodies to the drug which cause a mild to moderate thrombocytopenia and can progress the patient into a severe prothrombotic state.2 The prothrombotic state can be detrimental due to venous and arterial thromboembolisms that lead to life and limb-threatening manifestations. The mechanism of the thrombocytopenia and immune reaction was not identified until 1973.2 The adverse drug effect is induced by platelet-activating antibodies against platelet factor 4 (PF4) and heparin.3 These antibodies can occur without clinical complications in some patients, however, a percentage of those have identified thrombosis. Heparin induced thrombocytopenia (HIT) is estimated to occur in about 5% of patients that receive heparin and has an overall mortality rate of 30%.4 The incidence rate is increased in patients that pose certain risk factors. Some of the risk factors include receiving unfractionated heparin (UFH) over low-molecular-weight heparin (LMWH), age extremes, being female, and those who are recipients of heparin due to surgery such as coronary artery bypass graft (CABG) or hip arthroscopy5 as opposed to a medical or obstetric reason. Due to the potential detrimental effects of HIT, it is important to recognize the disease and discontinue any heparin-related products while also administering an alternative anticoagulant.

HIT can be divided into 2 types. The first type, formerly called HIT type I, is benign, nonthrombotic and not linked to the immune system. The second, formerly called HIT type II, refers to the classic immune-mediated prothrombotic disease. Typically, in clinical settings, HIT is referring to the immune-mediated type and will be the focus of this article.

Recommended Citation

Yatskiv, Tanya, "Heparin Induced Thrombocytopenia (HIT)" (2023). Doctor of Medical Science (DMSc). 17.
https://digitalcommons.georgefox.edu/dmsc/17