A prospective study on the incidence and clinical relevance of heparin-induced antibodies in patients after vascular surgery

Thromb Res. 2000 Mar 15;97(6):387-93. doi: 10.1016/s0049-3848(99)00198-x.


The heparin-platelet factor 4-antibody assay, polyanion-platelet factor 4-antibody assay and heparin-induced platelet activation test are used for laboratory diagnosis of the immune form of heparin-induced thrombocytopenia. Fifty consecutive patients receiving heparin treatment for more than 5 days after vascular surgery were prospectively screened for heparin-induced thrombocytopenia antibodies, thrombocytopenia (daily platelet counts), deep-vein thrombosis (color-coded duplex sonography), and arterial reocclusion (clinical assessment). None of the patients developed thrombocytopenia or thrombosis in association with formation of heparin-induced thrombocytopenia antibodies. Despite the absence of clinical evidence of heparin-induced thrombocytopenia, many patients formed heparin-induced thrombocytopenia antibodies: 34% of the patients were positive in the heparin-platelet factor 4-antibody assay, 28% in the polyanion-platelet factor 4-antibody assay, 14% in the heparin-induced platelet activation test, and 54% with any of these tests. Patients predominantly developed IgM (24%) and IgA antibodies (16%), whereas IgG antibodies were found in 12% of patients. Whereas the majority of patients with positive ELISA assays had IgM and IgA antibodies, patients with a positive functional assay (heparin-induced platelet activation test) predominantly had IgG antibodies. We conclude that a high percentage of patients develop heparin-induced antibodies after vascular surgery without any clinical symptoms of heparin-induced thrombocytopenia. None of the assays therefore is predictive of the clinical manifestation of heparin-induced thrombocytopenia in asymptomatic patients. Therefore, the diagnostic specificity of both antigen and activation assays for heparin-induced thrombocytopenia appears to be relatively low in the vascular surgery patient population.

MeSH terms

  • Aged
  • Antibodies / analysis
  • Antibodies / drug effects*
  • Anticoagulants / adverse effects*
  • Anticoagulants / therapeutic use
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Germany / epidemiology
  • Heparin / adverse effects*
  • Heparin / therapeutic use
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Platelet Activation / drug effects
  • Platelet Factor 4 / analysis
  • Platelet Factor 4 / drug effects
  • Prospective Studies
  • Thrombocytopenia / chemically induced*
  • Thrombocytopenia / epidemiology
  • Thrombocytopenia / immunology
  • Time Factors
  • Vascular Diseases / blood
  • Vascular Diseases / surgery*


  • Antibodies
  • Anticoagulants
  • Platelet Factor 4
  • Heparin