A prospective study on the incidence and clinical relevance of heparin-induced antibodies in patients after vascular surgery.
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.
Lindhoff-Last
E
E
Medical Department of Internal Medicine, University Hospital Frankfurt, Frankfurt, Germany. Lindhoff-Last@em.uni-frankfurt.de
Eichler
P
P
Stein
M
M
Plagemann
J
J
Gerdsen
F
F
Wagner
R
R
Ehrly
A M
AM
Bauersachs
R
R
D000368:Aged; D000906:Antibodies / Q000032:analysis / Q000187:drug effects*; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005858:Germany / Q000453:epidemiology; D006493:Heparin / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects; D010978:Platelet Factor 4 / Q000032:analysis / Q000187:drug effects; D011446:Prospective Studies; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000453:epidemiology / Q000276:immunology; D013997:Time Factors; D014652:Vascular Diseases / Q000097:blood / Q000601:surgery*
D000906:Antibodies; D000925:Anticoagulants; D010978:Platelet Factor 4; D006493:Heparin