title: Assessment of HIT antibody complex in hip fracture patients receiving enoxaparin or unfractionated heparin.
abstract: Thromboembolic disease is a common complication of hip fracture in the elderly. Anticoagulants represent a standard of care in preventing postoperative thrombotic complications following surgical fixation. We asked whether levels of antibody to heparin-platelet factor 4 (PF4) complex were differentially present in unfractionated heparin (UFH) versus Enoxaparin, following hip fracture and whether one particular subtype of antibodies was more prevalent. Plasma samples from elderly patients sustaining a hip fracture treated with either enoxaparin or UFH were collected pre- and postoperatively and analyzed using enzyme-linked immunosorbent assay (ELISA) sandwich method for the prevalence of antiheparin-PF4 antibodies and later subtyped. The prevalence of antiheparin-PF4 antibodies was higher in the UFH group especially on postoperative day 7. Patients treated with UFH showed a greater prevalence of antiheparin-PF4 antibodies and a greater prevalence of immunoglobulin G (IgG) subtype. Heparin and enoxaparin are capable of generating heparin-induced thrombocytopenia (HIT) antibodies in elderly patients undergoing orthopedic surgery but perhaps not to the same extent. When comparing low-molecular-weight heparin (LMWH) with UFH, the incidence of new antiheparin-PF4 antibody production is higher in patients treated with UFH.
authors.affiliation: Loyola University Chicago Stritch School of Medicine, 2160 S First Ave, Maywood, IL, USA.
authors.forename: Justin W
authors.initials: JW
authors.lastname: Griffin
authors.forename: William J
authors.initials: WJ
authors.lastname: Hopkinson
authors.forename: Michael R
authors.initials: MR
authors.lastname: Lassen
authors.forename: Indermohan
authors.initials: I
authors.lastname: Thethi
authors.forename: Evangelos
authors.initials: E
authors.lastname: Litinas
authors.forename: Jawed
authors.initials: J
authors.lastname: Fareed
mesh_terms: D000368:Aged; D000906:Antibodies / Q000276:immunology*; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use; D017984:Enoxaparin / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006493:Heparin / Q000009:adverse effects / Q000276:immunology* / Q000627:therapeutic use; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects / Q000627:therapeutic use*; D006620:Hip Fractures / Q000188:drug therapy* / Q000276:immunology / Q000601:surgery; D006801:Humans; D008297:Male; D010978:Platelet Factor 4 / Q000276:immunology*; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D013927:Thrombosis / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control; D020246:Venous Thrombosis / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control
chemical_list: D000906:Antibodies; D000925:Anticoagulants; D017984:Enoxaparin; D006495:Heparin, Low-Molecular-Weight; D010978:Platelet Factor 4; D006493:Heparin