Heparin-induced thrombocytopenia.
Heparin is widely used for the prevention and treatment of thrombotic and particularly cardiovascular disorders. Unfortunately, 0.5 to 3.0% of patients given heparin develop an immune reaction, commonly termed Type II heparin-induced thrombocytopenia (HIT). This is characterized by a moderate thrombocytopenia and in some patients, a venous or arterial thrombosis. This frequently leads to disastrous sequelae, such as limb amputation and death. The pathophysiological basis of this serious adverse drug reaction is the production of an immunoglobulin G antibody that reacts with an antigenic complex consisting of heparin and platelet factor 4. A significant risk factor for the development of HIT is recent surgery, and the frequency of developing an antiheparin-platelet factor 4 or HIT antibody is particularly high in cardiac surgery patients, although surprisingly, only a few of these patients actually develop the clinical syndrome of HIT. This review will discuss the frequency, pathophysiology, clinical features, diagnosis and management of HIT.
Chong
Beng H
BH
Department of Medicine, St George Clinical School and Centre of Vascular Research, University of New South Wales, Sydney, New South Wales, USA. beng.chong@unsw.edu.au
Chong
James J H
JJ
D000925:Anticoagulants / Q000009:adverse effects*; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D010978:Platelet Factor 4 / Q000502:physiology; D012307:Risk Factors; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000175:diagnosis / Q000628:therapy
D000925:Anticoagulants; D010978:Platelet Factor 4; D006493:Heparin