Levine, Robert L., Hergenroeder, Georgene W., Francis, John L., Miller, Charles C., Hursting, Marcie J.
funding text
This study was supported by a grant from GlaxoSmithKline. Dr. Levine and Dr. Francis have received grant support and consultancy fees from GlaxoSmithKline. Dr. Hursting has received consultancy fees from GlaxoSmithKline. Ms. Hergenroeder and Dr. Miller have no conflicts of interest related to this 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 +/- A 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.