Prevalence and risk of preexisting heparin-induced thrombocytopenia antibodies in patients with acute VTE

Theodore E. Warkentin, Bruce L. Davidson, Harry R. Büller, Alexander Gallus, Michael Gent, Anthonie W A Lensing, Franco Piovella, Martin H. Prins, Annelise E M Segers, John G. Kelton

Research output: Contribution to journalArticlepeer-review


Background: Some patients with acute VTE who may previously have been exposed to heparin products have unrecognized antibodies implicated in heparin-induced thrombocytopenia (HIT). Antibody prevalence and patient consequences upon exposure to heparin, low-molecular-weight heparin, and fondaparinux are uncertain. Methods: In this secondary analysis, we tested patients in the Matisse VTE studies at study entry for heparin-dependent antibodies and further tested patients with enzyme-linked immunosorbent assay (ELISA)-positive results for platelet-activating antibodies. We compared the risk of HIT (>50% fall in platelet count, heparin-dependent antibodies, no contradicting features) between patients treated with heparin (either unfractionated or low molecular weight [enoxaparin]) vs those who received fondaparinux. Comparison groups for thrombocytopenia occurrence comprised patients with ELISA-positive, platelet-activating, antibody-positive results; ELISA-positive, but platelet-activating antibody-negative results;and randomly selected antibody-negative results. Results: A total of 127 of 3,994 patients (3.2%) had ELISA-positive results at baseline, but only 14 (0.4%; 95% CI, 0.2%-0.6%) had platelet-activating antibodies. Among these 14, four treated with unfractionated or low-molecular-weight heparin developed HIT compared with zero of 10 fondaparinux-treated patients (OR, 95; 95% CI, 8-1,123; P

Original languageEnglish
Pages (from-to)366-373
Number of pages8
Issue number2
Publication statusPublished - Aug 1 2011

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine
  • Cardiology and Cardiovascular Medicine


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