Heparin-induced thrombocytopenia in patients with ventricular assist devices: are new prevention strategies required?
Heparin-induced thrombocytopenia (HIT) is caused by platelet-activating antiplatelet factor 4/heparin antibodies. However, clinical HIT (thrombocytopenia or thrombosis, or both) develops in only a minority of patients who form antibodies. It is difficult to distinguish HIT from non-HIT thrombocytopenia in patients after ventricular assist device (VAD) implantation. Further, the risks of heparin-induced immunization and clinical HIT approach 65% and 10%, respectively, in this patient population, with a particularly high risk of cerebrovascular ischemia/infarction. Given the apparent high risk of HIT and its complications, and the diagnostic challenges, we suggest that the VAD patient population be evaluated using alternative, nonheparin agents for routine postimplantation anticoagulation.
Warkentin
Theodore E
TE
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. twarken@mcmaster.ca
Greinacher
Andreas
A
Koster
Andreas
A
D000917:Antibody Formation; D000925:Anticoagulants / Q000009:adverse effects; D001323:Autoantibodies; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000379:methods; D002648:Child; D006353:Heart-Assist Devices; D006493:Heparin / Q000009:adverse effects* / Q000097:blood / Q000276:immunology; D006801:Humans; D007238:Infarction / Q000517:prevention & control; D008954:Models, Biological; D010978:Platelet Factor 4 / Q000276:immunology; D012307:Risk Factors; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000517:prevention & control*; D013927:Thrombosis / Q000139:chemically induced / Q000517:prevention & control
D000925:Anticoagulants; D001323:Autoantibodies; D010978:Platelet Factor 4; D006493:Heparin