A Prospective Study on the Incidence and Clinical Relevance of Heparin-Induced Antibodies in Patients after Vascular Surgery

• Published in: Thrombosis research 2000-03, Vol.97 (6), p.387-393
• Main Authors: Lindhoff-Last, Edelgard, Eichler, Petra, Stein, Martina, Plagemann, Judith, Gerdsen, Frank, Wagner, Richard, Ehrly, Albert M., Bauersachs, Rupert
• Format: Article
• Language: English
• Subjects: Aged; Antibodies - analysis; Antibodies - drug effects; Anticoagulants - adverse effects; Anticoagulants - therapeutic use; Biological and medical sciences; Enzyme-Linked Immunosorbent Assay; Female; Germany - epidemiology; Heparin - adverse effects; Heparin - therapeutic use; Heparin-induced antibodies; Heparin-induced thrombocytopenia; Humans; Incidence; Male; Medical sciences; Middle Aged; Platelet Activation - drug effects; Platelet Factor 4 - analysis; Platelet Factor 4 - drug effects; Prospective Studies; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Thrombocytopenia - chemically induced; Thrombocytopenia - epidemiology; Thrombocytopenia - immunology; Time Factors; Vascular Diseases - blood; Vascular Diseases - surgery; Vascular surgery
• ISSN: 0049-3848; 1879-2472
• 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.