Anzeige
Anzeige

Archive

Clinical features of heparin-induced thrombocytopenia including risk factors for thrombosis A retrospective analysis of 408 patients

Journal: Thrombosis and Haemostasis
ISSN: 0340-6245
DOI: https://doi.org/10.1160/TH04-12-0825
Issue: 2005: 94/1 (July) pp. 1-232
Pages: 132-135

Clinical features of heparin-induced thrombocytopenia including risk factors for thrombosis A retrospective analysis of 408 patients

Andreas Greinacher1 , Beate Farner1 , Hartmut Kroll2 , Thomas Kohlmann³, Theodore E. Warkentin4 , Petra Eichler1
1 Institut für Immunologie und Transfusionsmedizin, Ernst-Moritz-Arndt-Universität Greifswald, Germany 2 Institut für Klinische Immunologie und Transfusionsmedizin, Justus-Liebig-Universität Giessen, Germany 3 Institut für Community Medicine, Ernst-Mori

Summary

Immune mediated heparin induced thrombocytopenia (HIT) is a prothrombotic adverse effect of heparin. However, only a subgroup of patients with HIT develops thromboembolic complications. We aimed to identify risk factors for developing HITassociated thrombosis.We analyzed a registry of patients with clinical suspicion of HIT who tested positive using a sensitive functional assay.Patient information was obtained by a standardized questionnaire. By multivariate analysis the association of age, gender, type of patient population, and magnitude of the platelet count decline with the frequency, type (venous or arterial), and temporal pattern of thrombotic events was assessed. In 408 HIT patients we observed predominance of venous thrombosis (2.4:1), with 40% of patients developing a pulmonary embolism. However, in the subgroup of post-cardiovascular surgery patients there was predominance of arterial thrombosis (1:8.5). The type of arterial thrombosis (limb artery thrombosis > thrombotic stroke > myocardial infarction) was the converse of that observed with typical atherothrombotic clots in non-HIT populations. In 59.8% of patients HIT-related thrombosis manifested either on the same day a platelet count decrease >50% was documented (26.3%) or before the decrease in platelet counts (33.5%).The most important risk factors for thrombosis were orthopedic/trauma surgery and the magnitude of platelet count decrease. HIT-associated thrombosis occurs in a considerable proportion of patients before platelet counts decrease by more than 50%.