Fondaparinux-Associated Heparin-Induced Thrombocytopenia

Abstract

Heparin-induced thrombocytopenia (HIT) is an immune-mediated clinical syndrome of thrombocytopenia and thrombosis occurring after exposure to heparin. HIT most commonly occurs after exposure to unfractionated heparin but has also been reported with low-molecular-weight heparin. To date, there have been very few reports of HIT with the pentasaccharide fondaparinux, and some have proposed fondaparinux as a treatment for HIT. This article presents two cases of HIT associated with fondaparinux use.

Spontaneous heparin-induced thrombocytopenia syndrome: 2 new cases and a proposal for defining this disorder

“…To date, 6 relatively well-documented cases of HIT following fondaparinux thromboprophylaxis have been reported, [8][9][10][11][12] without any apparent preceding heparin exposure. Notably, 5 of the 6 patients had preceding orthopedic surgery (all but 1 post-knee replacement), raising the possibility that fondaparinux could be an innocent bystander, ie, the orthopedic surgery itself could have been the trigger of the subsequent anti-PF4/heparin immune response.…”

“…We also suggest that the existence of spontaneous HIT syndrome following orthopedic surgery confounds interpretation of fondaparinux-associated HIT reported in that patient population. [8][9][10][11][12] Study design Patient …”

Fondaparinux‐associated heparin‐induced thrombocytopenia

“…Cases that did not meet these criteria, but where fondaparinux seemed to be the likely cause, were categorized as possible fondaparinux‐associated HIT. This happened in only two cases; the first patient developed thrombocytopenia 10 d after initiation of fondaparinux and nadir platelet count within 24 h of initiation of UFH, whereas the second patient developed thrombocytopenia 7–10 d after initiation of fondaparinux and three daily doses of LMWH .…”

Suspicion of heparin-induced thrombocytopenia in internal medicine: How appropriate is the ordering of anti-PF4/heparin antibody testing?

“…Inclusion criteria were the use of UFH, LMWH, or fondaparinux (as there are few reports on isolated cases of HIT associated with fondaparinux [15][16][17]), and hospitalization for a minimum of 5 days. Exclusion criteria were the absence of thrombocytopenia or of platelet count fall potentially corresponding to an ordering error and patients transferred from other hospitals (drug lists not always available).…”