Abstract
Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse effect of heparin therapy and is strongly associated with venous and arterial thrombosis. HIT should be recognized as a clinicopathologic syndrome in which clinical events (thrombocytopenia and thromboembolism) are attributed to platelet-activating antibodies (HIT Abs) that recognize platelet factor 4/heparin complexes. eTypicalf HIT occurs 5 to 14 days after heparin administration. Some patients develop HIT several days after heparin discontinuation (delayed-onset) or soon after the re-administration of heparin (rapid-onset), because of residual circulating HIT Abs due to recent heparin treatment. Thromboembolic events occur in 25 to 50% of HIT patients and the thrombotic death rate can reach 5%, if the diagnosis is delayed and/or patients are treated inappropriately. Therefore, all heparin administration including heparin flushes should be discontinued and substituted with a thrombin inhibitor such as argatroban, which was recently approved by the Japanese regulatory agency for HIT treatment. To investigate the incidence of HIT in acute stroke patients treated with heparin, we have conducted retrospective and multicenter, prospective cohort studies. Our results suggest that the incidence of HIT in Japan may be similar or slightly lower than that in Western countries. HIT diagnosis should be included in the medical management of stroke patients to avoid further complications.
