Heparin-induced thrombocytopenia: a review of concepts regarding a dangerous adverse drug reaction

Abstract

Heparin is a natural agent with antithrombotic action, commercially available for therapeutic use as unfractionated heparin and low molecular weight heparin. Heparin-induced thrombocytopenia (HIT) is a serious adverse reaction to heparin that promotes antibody-mediated platelet activation. HIT is defined as a relative reduction in platelet count of 50% (even when the platelet count at its lowest level is above>150 x 10(9)/L) occurring within five to 14 days after initiation of the therapy. Thrombocytopenia is the main feature that directs the clinical suspicion of the reaction and the increased risk of thromboembolic complications is the most important and paradoxical consequence. The diagnosis is a delicate issue, and requires a combination of clinical probability and laboratory tests for the detection of platelet activation induced by HIT antibodies. The absolute risk of HIT has been estimated between 1% and 5% under treatment with unfractionated heparin, and less than 1% with low molecular weight heparin. However, high-quality evidence about the risk of HIT from randomized clinical trials is scarce. In addition, information on the frequency of HIT in developing countries is not widely available. This review aims to provide a better understanding of the key features of this reaction and updated information on its frequency to health professionals and other interested parties. Knowledge, familiarity, and access to therapeutic options for the treatment of this adverse reaction are mandatory to minimize the associated risks, improving patient safety.

Heparinized and Saline Solutions in the Maintenance of Arterial and Central Venous Catheters After Cardiac Surgery

“…Heparin, even with low dose, can cause thrombocytopenia and bleeding ( 8 - 10 ). The absolute risk of heparin-induced thrombocytopenia (HIT) with unfractionated heparin is 1% - 5% ( 11 , 12 ).…”

Heparina para desobstrução de cateter venoso central de inserção periférica no recém‐nascido: estudo in vitro

“…The action mechanism of the heparin depends on its binding to a plasma cofactor, the antithrombin, thereby inactivating thrombin (factor IIa) and the activated coagulation factor X, preventing the conversion of prothrombin into thrombin, and of fibrinogen into fibrin. 21 The advantages of SLMWH include: no interference of diet or medications on its action mechanism and minimum monitoring; when compared to unfractionated heparin, it does not show increased risk of bleeding, and it reduces the incidence of heparin-induced thrombocytopenia when used alone. 22 …”

“…O mecanismo de ação da heparina depende da ligação de um cofator do plasma, a antitrombina, que inativa a trombina (fator IIa) e o fator de coagulação X ativado e previne a conversão da protrombina em trombina e do fibrinogênio em fibrina. 21 As vantagens HSBPM incluem: não interferência da dieta ou medicamentos sobre seu mecanismo de ação; monitoração mínima; quando comparada à heparina não fracionada, não apresenta maior risco de sangramento e diminui a incidência de trombocitopenia induzida por heparina quando em uso isolado. 22 …”

Identification of potential targets for an anticoagulant pectin

“…ACCEPTED MANUSCRIPT 12 bruises, contact dermatitis, urticarial, and necrosis of epithelial tissue, to name a few [12,13,[34][35][36]. In this regard, the search for alternative medication is indispensable.…”