Direct thrombin inhibitors are not dependent on antithrombin for anticoagulation effect.
There is increasing interest in using direct thrombin inhibitors (DTIs) as an alternative to UNFH for ECMO anticoagulation. DTIs have been used in both pediatric and adult ECMO patients with HIT or heparin resistance. [1-5] DTIs are not dependent on antithrombin for anticoagulation effect. Currently, there are two commercially available intravenous DTIs, argatroban and bivalirudin. Bivalirudin has a relatively short elimination half-life of 25 to 30 minutes, making it an ideal anticoagulant for patients at high risk of bleeding. 
 Nagle EL, Dager WE, Duby JJ, et al. Bivalirudin in pediatric patients maintained on extracorporeal life support. Pediatric Crit Care Med 2013
 Ranucci M, Ballotta A, Kandil H, et al. Bivalirudin-based versus conventional heparin anticoagulation for postcardiotomy extracorporeal membrane oxygenation. Critical Care 2011
 Phillips MR, Khoury AI, Ashton RF, Cairns BA, Charles AG. The dosing and monitoring of argatroban for heparin-induced thrombocytopenia during extracorporeal membrane oxygenation: a word of caution. Anaesthesia and Intensive Care 2014
 Beiderlinden M, Treschan T, Gorlinger K, Peters J. Argatroban in extracorporeal membrane oxygenation. Artificial Organs 2007
 Young G, Yonekawa KE, Nakagawa P, Nugent DJ. Argatroban as an alternative to heparin in extracorporeal membrane oxygenation circuits. Perfusion 2004
 Gladwell TD. Bivalirudin: a direct thrombin inhibitor. Clin Ther 2002