Heparin-platelet factor 4 antibodies in intensive care patients: an observational seroprevalence study.

Abstract

Heparin-platelet factor 4 (PF4) antibodies mediate heparin-induced thrombocytopenia (HIT) and, irrespective of thrombocytopenia, are associated with poorer outcomes in some patients. The prevalence of heparin-PF4 antibodies, including platelet-activating ones, in patients in the medical, neurotrauma, or shock-trauma intensive care unit (ICU) remains unclear. In this single-center, observational study, heparin-PF4 antibodies (IgG/A/M) were measured by ELISA in 185 adults (median APACHE II score, 16) admitted to the medical (n = 27), neurotrauma (n = 96), or shock-trauma (n = 62) ICU and after 7 +/- 2 days. Seropositive patients and heparin-treated patients with unexplained, new-onset thrombocytopenia were also tested for platelet-activating antibodies using a serotonin release assay (SRA). Of 185 patients, seropositivity occurred in 20 patients (10.8%; 95% CI 6.7-16.2%) at admission and 54 (29.2%, 95% CI 22.8-36.3%) after 7 days (P < 0.001). Platelet-activating antibodies occurred in 4 seropositive patients at admission and 9 seropositive patients after 7 days (including in 1 patient at each assessment), each without thrombocytopenia or new thrombosis. Of 12 seropositive patients with platelet-activating antibodies, 6 had an ELISA optical density (OD) >1.0. ELISA-positive, SRA-negative, suspected HIT occurred in 1 patient. Heparin-PF4 antibodies are present in 10.8% of medical, neurotrauma, or shock-trauma ICU patients at admission and increase significantly to 29.2% within 7 days. Approximately 17-20% of seropositive ICU patients, often those with an ELISA OD >1.0, have platelet-activating heparin-PF4 antibodies.

• Authors: Robert L Levine, Georgene W Hergenroeder, John L Francis, Charles C Miller, Marcie J Hursting
• Journal: Journal of thrombosis and thrombolysis (J Thromb Thrombolysis) Vol. 30 Issue 2 Pg. 142-8 (Aug 2010) ISSN: 1573-742X [Electronic] Netherlands
• PMID: 19911252 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies
• Anticoagulants
• Platelet Factor 4
• Heparin

Topics

• APACHE
• Antibodies (blood)
• Anticoagulants (immunology)
• Critical Care
• Enzyme-Linked Immunosorbent Assay
• Female
• Heparin (immunology)
• Hospital Mortality
• Humans
• Intensive Care Units
• Length of Stay
• Male
• Middle Aged
• Platelet Activation (immunology)
• Platelet Factor 4 (immunology)
• Prospective Studies
• Seroepidemiologic Studies
• Texas (epidemiology)
• Thrombocytopenia (blood, epidemiology, immunology, mortality)
• Time Factors
• Treatment Outcome