From the Guidelines
Argatroban and heparin have similar efficacy and safety profiles in patients undergoing extracorporeal membrane oxygenation (ECMO), but the choice between them should be based on individual patient factors, such as heparin-induced thrombocytopenia (HIT) or renal impairment, with argatroban being preferred in these situations. The most recent and highest quality study, a propensity-score matched observational noninferiority study by Fisser et al., 2021 [@49@], found that argatroban was noninferior to unfractionated heparin (UFH) regarding bleeding and thrombosis in patients undergoing ECMO. Key points to consider when choosing between argatroban and heparin include:
- Argatroban is a direct thrombin inhibitor that does not interact with platelet factor 4, making it safe for patients with HIT or a history of HIT.
- The typical starting dose for argatroban is 0.2 mg/kg/min as a continuous IV infusion, adjusted to maintain the aPTT at 1.5-3 times baseline, as seen in a study by Beiderlinden et al., 2019 [@50@].
- Heparin, either unfractionated (UFH) or low molecular weight (LMWH), is the standard anticoagulant for most other situations requiring anticoagulation, with UFH being dosed at 80 units/kg bolus followed by 18 units/kg/hr infusion.
- Argatroban is also preferred in patients with significant renal impairment who need anticoagulation, as it is hepatically cleared, while heparin requires dose adjustment in renal failure.
- For patients transitioning to warfarin, argatroban significantly elevates the INR, requiring careful monitoring during the transition period. In terms of monitoring, both argatroban and heparin require regular monitoring of aPTT, with argatroban also requiring monitoring of liver function tests due to its hepatic clearance, as noted in a study by Dingman et al., 2020 [@77@]. Overall, the choice between argatroban and heparin should be based on individual patient factors, with argatroban being preferred in patients with HIT or renal impairment, and heparin being preferred in most other situations.
From the Research
Comparison of Argatroban and Heparin
- Argatroban is a synthetic direct thrombin inhibitor used as an alternative anticoagulation in patients with heparin-induced thrombocytopenia (HIT) 1, 2, 3.
- Heparin, on the other hand, is a commonly used anticoagulant that can cause HIT, a serious adverse effect characterized by platelet-activating heparin-dependent antibodies 1.
- Unfractionated heparins seem to induce HIT more often than low molecular weight heparins 1.
- Argatroban is mainly eliminated by the liver, making it a preferable option for patients with renal impairment 1, 3.
- In contrast, heparin is not suitable for patients with HIT, and its use should be discontinued immediately upon diagnosis 1, 2.
Efficacy and Safety
- Argatroban has been shown to be effective in managing HIT, with a low risk of bleeding complications 2, 4, 5.
- Fondaparinux, another anticoagulant, has been used off-label for HIT treatment and has been found to be effective and safe, with no HIT-specific complications reported in fondaparinux-treated patients 4, 5.
- Heparin, however, is associated with a higher risk of thrombosis and bleeding complications in patients with HIT 1, 2.
Monitoring and Dosing
- Activated partial thromboplastin time (aPTT) is sufficient to monitor argatroban treatment in most cases 1, 3.
- Argatroban dosing requires careful management, especially in patients with hepatic and renal failure 3.
- Fondaparinux has been used at prophylactic doses in some patients with suspected HIT, with similar effectiveness and safety as argatroban and danaparoid 4.