Heparin-induced thrombocytopenia in intensive care patients

OBJECTIVE: To summarize new information on frequency of heparin-induced thrombocytopenia (HIT) in patients treated in intensive care units (ICU), developments in the interpretation of assays for detecting anti-PF4/heparin antibodies, and treatment of HIT patients. STUDY SELECTION: All data on the frequency of laboratory-confirmed HIT in ICU patients were included; for laboratory testing of HIT and treatment of patients, this review focuses on recent data that became available in 2005 and 2006. DATA EXTRACTION AND SYNTHESIS: HIT is a potentially life-threatening adverse effect of heparin treatment caused by platelet-activating antibodies of immunoglobulin G class usually recognizing complexes of platelet factor 4 and heparin. HIT is more often caused by unfractionated heparin than low-molecular-weight heparin and is more common in postsurgical than in medical patients. In the ICU setting, HIT is uncommon (0.3-0.5%), whereas thrombocytopenia from other causes is very common (30-50%). For laboratory diagnosis of HIT antibodies, both antigen assays and functional (platelet activation) assays are available. Both tests are very sensitive (high negative predictive value) but specificity is problematic, especially for the antigen assays, which also detect nonpathogenic immunoglobulin M and immunoglobulin A class antibodies. Detection of immunoglobulin M or immunoglobulin A antibodies could potentially lead to adverse events such as bleeding if a false diagnosis of HIT prompts replacement of heparin by an alternative anticoagulant. For treatment of HIT, three alternative anticoagulants are approved: the direct thrombin inhibitors, lepirudin and argatroban, and the heparinoid, danaparoid (not approved in the United States). Recent data indicate that the approved dosing regimens of the direct thrombin inhibitors are too high, especially in ICU patients. CONCLUSIONS: HIT affects <1% of ICU patients even though 30-50% develop thrombocytopenia. The choice of the optimal alternative anticoagulant depends on patient characteristics. Many ICU patients require lower doses of alternative anticoagulant than those recommended by the manufacturer.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Critical-care review of HIT laboratory testing, antigen/functional assays, and treatment with lepirudin, argatroban, or danaparoid; notes that manufacturer-recommended dosing of direct thrombin inhibitors is too high for ICU patients.

Leech-derived molecules this paper discusses, each with a full profile in the ASH compound registry:

Explore how this research connects to clinical practice

More peer-reviewed studies in Drug Development.

• Novel Leech Antimicrobial Peptides — Hirunipins — Kumar et al. (2025)
• Medicinal Leech Genome Assembly — Anticoagulant Gene Catalog — Kvist et al. (2020)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• Hirudotherapy in Medicine and Dentistry — Jha K et al. (2015)
• Medicinal leech therapy (hirudotherapy): a brief overview — Singh A (2010)
• HIRUDOTHERAPY IN PRESBYACUZIS PRAECOX IN CLEAN-UP WORKERS AFTER THE CHORNOBYL ACCIDENT DURING THE POST-CATASTROPHE YEARS — Zabolotnyi D, Mishchanchuk N (2019)
• Investigation of oxidant-antioxidant status in patients treated with hirudotherapy: an experimental study — Sarikan I, Savas H (2024)
• Leech therapeutic applications — Abdualkader A et al. (2013)
• Non-Occlusive Mesenteric Ischemia Due to Hirudotherapy: A Case Report — Akalın Ç, Ekmen N (2020)
• Leech therapy: a history — Hyson J (2005)

Browse all ASH-analysed research →