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

摘要

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 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.