Heparin-Induced Thrombocytopenia

This chapter provides a comprehensive overview of Heparin-Induced Thrombocytopenia (HIT), a critical and often challenging complication of heparin therapy. Emphasizing both the epidemiology and pathophysiology of HIT, the chapter delves into the nuances of its two types: Type I (non-immune response) and Type II (immune-mediated). Key factors influencing HIT, such as heparin type, duration of exposure, and patient-specific variables like age and surgical history, are examined in detail. The chapter highlights the complex immune response involving platelet factor 4 (PF4) and heparin complexes, leading to platelet activation and thrombocytopenia. Diagnostic strategies, including clinical scoring systems like the 4T’s and laboratory assays (immunoassays and functional assays), are thoroughly discussed. The management section offers insights into various treatment strategies, ranging from the immediate cessation of heparin to the use of alternative anticoagulants such as Argatroban, Bivalirudin, and Direct Oral Anticoagulants (DOACs). Special focus is given to the challenges of re-exposing patients to heparin post-HIT and the potential of emerging therapies. This chapter serves as a vital resource for healthcare professionals, offering a blend of clinical insight and evidence-based practices for the effective management of HIT.