What is the management of Heparin-Induced Thrombocytopenia (HIT) in the Intensive Care Unit (ICU)?

From the Guidelines

Management of heparin-induced thrombocytopenia (HIT) in the ICU requires immediate discontinuation of all heparin products and initiation of a non-heparin anticoagulant, such as argatroban or lepirudin, as recommended by the American College of Chest Physicians evidence-based clinical practice guidelines 1. The choice of non-heparin anticoagulant depends on the patient's renal function, with argatroban preferred in renal dysfunction 1.

• Key considerations in managing HIT include:
  • Monitoring platelet counts daily until recovery begins
  • Avoiding the use of warfarin until platelet counts recover to >150,000/μL
  • Overlapping warfarin with a non-heparin anticoagulant for at least 5 days with an INR >2.0
  • Continuing anticoagulation for 1-3 months after isolated HIT and 3-6 months if thrombosis occurred
• The American College of Chest Physicians recommends the use of nonheparin anticoagulants, such as lepirudin, argatroban, and danaparoid, over the further use of heparin or low-molecular-weight heparin (LMWH) or initiation/continuation of a vitamin K antagonist (VKA) in patients with HIT with thrombosis (HITT) or isolated HIT 1.
• In patients with a past history of HIT who have acute thrombosis (not related to HIT) and normal renal function, fondaparinux at full therapeutic doses may be used until transition to a VKA can be achieved 1.

From the FDA Drug Label

Argatroban is a direct thrombin inhibitor indicated: (1) For prophylaxis or treatment of thrombosis in adult patients with heparin-induced thrombocytopenia (HIT) The dose for heparin-induced thrombocytopenia without hepatic impairment is 2 mcg/kg/min administered as a continuous infusion Discontinue heparin therapy and obtain a baseline aPTT before administering Argatroban After the initial dose of Argatroban, the dose can be adjusted as clinically indicated

The management of heparin-induced thrombocytopenia (HIT) in ICU patients involves discontinuing heparin therapy and administering Argatroban at an initial dose of 2 mcg/kg/min as a continuous infusion. The dose can be adjusted as clinically indicated after obtaining a baseline aPTT. It is essential to monitor therapy and follow dosage adjustments recommendations, especially in patients with hepatic impairment 2. Key considerations include:

• Discontinuing all parenteral anticoagulants before administering Argatroban
• Adjusting dosing in patients with moderate or severe hepatic impairment
• Monitoring for signs of hemorrhage, as Argatroban can increase the risk of bleeding

From the Research

Management of Heparin-Induced Thrombocytopenia in ICU

• The management of heparin-induced thrombocytopenia (HIT) in the ICU involves immediate cessation of heparin and initiation of alternative anticoagulation therapy 3, 4.
• A high index of clinical suspicion is necessary to diagnose HIT, followed by an accurate clinical scoring assessment using the 4Ts 3.
• Laboratory testing must be undertaken to rule out HIT or establish the diagnosis, and alternative anticoagulation choices should be considered 3, 4.
• Parenteral thrombin inhibitors (argatroban, bivalirudin), parenteral factor Xa inhibitors (danaparoid, fondaparinux), and direct oral anticoagulants (DOACs) are potential treatment options for HIT 4, 5.
• Argatroban has been shown to have superior outcomes in the management of HIT, with shorter hospitalization length and lower rates of hemorrhagic events, thromboembolic events, and mortality 6.

Diagnosis and Treatment

• The diagnosis of HIT is based on clinical suspicion, laboratory testing, and demonstration of heparin-dependent platelet activation 7.
• The main symptom of HIT is the sudden onset of thrombocytopenia, involving a drop in the platelet count to less than 50% of the basal level, with or without the appearance of thrombotic complications 7.
• Once the diagnosis of HIT has been confirmed serologically or there is a high level of suspicion of HIT, heparin must be suspended and treatment with an alternative anticoagulant should be considered 7.

Alternative Anticoagulation Therapy

• Argatroban, lepirudin, desirudin, bivalirudin, and danaparoid are commonly used to manage HIT-related complications 6.
• Fondaparinux has been increasingly used for off-label treatment of HIT, and evidence for the use of DOACs has emerged 4, 5.
• However, the use of DOACs in acute HIT should be reserved for clinically stable patients without severe thrombotic complications, and fondaparinux is contraindicated in severe renal insufficiency 4, 5.