title: Management of the multiple phases of heparin-induced thrombocytopenia.
abstract: The clinical course of heparin-induced thrombocytopenia (HIT) may be separated into five sequential phases: 1. suspected HIT, 2. acute HIT, 3. subacute HIT A, 4. subacute HIT B, and 5. remote HIT. Each phase confronts the clinician with a unique set of management questions. In this review, the phases of HIT are defined and key management questions associated with each phase are discussed. Among patients with Suspected HIT, I use the 4Ts score to determine which patients have a sufficiently high probability of HIT to justify discontinuation of heparin and initiation of a non-heparin parenteral anticoagulant. An algorithm for selecting an appropriate non-heparin anticoagulant based on the patient's clinical stability, renal and hepatic function, drug availability, and physician comfort is provided. In patients with Acute HIT, I generally avoid prophylactic platelet transfusion and inferior vena cava filter insertion because of a potential increased risk of thrombosis. I perform 4-limb screening compression ultrasonography. In patients with symptomatic thromboembolism or asymptomatic proximal deep-vein thrombosis, I treat with anticoagulation for three months. In patients without thrombosis, I discontinue anticoagulation upon platelet count recovery. I do not transition patients to an oral anticoagulant until platelet count recovery (i. e. Subacute HIT A). I increasingly choose direct oral anticoagulants over vitamin K antagonists in this setting because of their greater convenience and safety. In Subacute HIT B and Remote HIT, I use heparin for cardiovascular surgery, whereas I use bivalirudin in patients with Acute HIT and Subacute HIT A in whom surgery cannot be delayed.
authors.affiliation: Adam Cuker, MD, MS, Penn Comprehensive Hemophilia and Thrombosis Program, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA, Tel.: +1 215 615 6555, Fax: +1 215 615 6599, E-mail: adam.cuker@uphs.upenn.edu.
authors.forename: Adam
authors.initials: A
authors.lastname: Cuker
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use*; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D010976:Platelet Count; D013921:Thrombocytopenia / Q000139:chemically induced / Q000628:therapy*; D013927:Thrombosis
chemical_list: D000925:Anticoagulants; D006493:Heparin
keywords: Heparin-induced thrombocytopenia; management; treatment